DE3991804C2 - Hip joint support - Google Patents

Abstract

The hip joint support consists of a rod (1) which can support a load equivalent to the maximum load on a patient's leg, connected at one end to the femur and at the other via a pviot (17,18) to the pelvic bone. The connection between the rod and femur is in the form of a shank (2) which is fitted into the femur in line with the axis of its diaphysis and set at an angle to the rod equal to that of the femur neck/diaphysis angle. - The length of the shank (2) inserted into the femur is equivalent to hold the length of the patient's femur, and it is fixed in place by a threaded surface. The shank is connected to the rod by a threaded joint which allows their positions to be adjusted. The pivot (17,18) can be in the form of a ball-and-socket joint or a two-way hinge.

Description

The invention relates to the field of medicine and especially surgery, orthopedics and traumatology and relates to an implantable hip joint distractor according to the preamble of claim 1.

In the human support and musculoskeletal system, this poses Hip joint an important and at the same time susceptible to damage Element that has to take a load that is more than corresponds to five times the weight of humans. In doing so the mobility of the femoral head in the hip joint pan the mobility of the lower extremity of the men bend or pull apart allow or pull away as well as when turning. The Winkelbe Thigh head movements in a healthy hip area steering are possible within very wide areas, namely the angle with respect to the bending is in the range from 120 to 150 °, with respect to the bending apart in the loading range from 10 to 15 °, in terms of pulling between 25 and 30 °, in terms of pulling away between 25 and 30 °, in relation to the external rotation between 60 and 80 ° and in Regarding the internal rotation between 40 and 70 °.

The angle when bending or unfolding it is the angle between the diaphyseal axis and the vertical axis of the human body in the sagittal level while the angle of pulling or pulling between the diaphyseal axis and the vertical axis of the Body lies in the frontal plane. The angle of rotation ent basically speaks the angle of rotation about the vertical Body axis. In this regard, all the angles mentioned reach in the physiological starting position of the thigh,  where the diaphyseal axis with respect to the vertical body peraxis lies at an angle of 87 °, its zero value.

In general, degenerative-dystrophic damage occurs hip joint compared to similar diseases other joints of the musculoskeletal system are much more common. The proportion of sufferers with Accordingly, coxarthrosis is very large and reaches at for example in Russia a share of 3 to 4% of ar viable population.

The coxarthrosis is with destructive changes in the hip articulated joint represents a particularly severe suffering, leads to incapacity for work and possibly also to incapacity ability to take care of itself in everyday life and calls constant pain.

The previously known treatment methods of pathological, destructive changes in the hip joint are described in con servative and surgical procedures divided. To the conservative treatment methods include the Heilgymna Stik without axial stress on the lower extremity, their Relief through extension while bedridden speed, the temporary gypsum immobilization, procedures, wel local blood circulation in the hip joint and overall stimulate extremity, massages, electrophoresis drive as well as methods of treatment with pharmaceutical Means.

In the best case it is with the conservative medicine drive possible, the further development of degenerative dystrophic processes, and only in their initial stages serve to delay. This fact is early diagnosis of coxarthrosis attributed even to him  experienced professionals is extremely difficult. For this The reason is very often degenerative in medical practice. second and third stage dystrophic processes act in which after x-ray examination of the sick Hip joint not only a significant narrowing of the Ge steering gap, but also a change in Contour of the femoral head and the acetabular cup is proven.

Surgical treatment procedures are currently due their better intensity and effectiveness compared to cons vative treatment methods clearly preferred. For this include osteotomy, arthrodesis, arthroplasty, bone arthroplasty, endoprosthesis of the joint surfaces, the operation of the soft tissues, the one-sided one putting endoprostheses, e.g. B. at the proximal end of the waiter femur or the acetabulum and the two sided, total replacement of the entire hip joint by Endo prostheses at the proximal end of the femur and the Acetabular cup, e.g. B. using hip joint Distraction devices.

Of all surgical treatment procedures of the Koxarthro se, whose goal is to restore the support and loading there are movement functions of the lower extremity a clear example of the use of full dentures worldwide given train. All other operations ver driving, like the osteotomy and arthrodesis, set one handles that serve to alleviate the complaints. In As a rule, such interventions only delay the course of the degenerative-dystrophic processes for a particular Time after which the use of a total endoprosthesis through orthopedic surgery.  

These surgical treatment methods consist of simultaneous, complete replacement of the resected end of the femur and the resected hip joint pan through an endoprosthesis from one opposite the body by indifferent material, such as plastic, metal or Ceramics.

When used in the body, endoprostheses lose through ab use and mechanical destruction make them operational speed. The lifespan of such endoprostheses is usually only half to a third of the lives maintenance of the sick. A new replacement of an endoprosthesis provides an engraving because of the lack of bone tissue of the problem, because when removing the endoprosthesis too a certain amount of biological material on the business the articulated joint must be removed, which in turn weaker attachment of the new prosthesis and the risk of complications from new surgical intervention fen brings with it. For this reason, the total opera tion using an artificial hip joint from the Orthopedic surgery is preferred in the elderly taken.

In addition, such surgical interventions are around extensive injuries and corresponding health issues hazards connected. The vital risk increases with cry aging particularly strongly as complications arise can complete removal of the Endopro make these necessary, whereby the lower extremity loses its functions permanently.

Surgical treatment methods are more promising, on the regenerative ability of the bone and cartilage pel tissue and in what are known as joint distraction  facilities are used to discharge the Hip joint while maintaining the support and movement properties of the lower extremity and mobility of the hip joint itself. The suitability of the Joint distraction device, an optimal position of the Femoral head inside the acetabular cup when open maintain the required joint space an important prerequisite for successful re manufacture of the joint.

There are currently two basic types of hip joint distraction ren, namely distractors that are only partially in the body the patient's implants, and distractors that are full are constantly implanted in the patient's body.

The use of joint distractors leads to a shortening increase in the length of bedriddenness. After the surgical The patient begins the operation after a short time the strain on the lower, operated limb. Through the Activation of muscle contractions becomes the lymphatic and Blood supply in the area of the damaged joint verb sert, rapid absorption of breakdown, hematoma and Edema products favored, the tissue renewal and the Ab improved the course of the regenerative processes, a recovery position of destroyed reflex connections enables the Ela Ensures the stability of the tape capsule apparatus and the Generation of synovial fluid intensified.

This stops the development of the degenerative-dystrophic Processes and the pain syndrome is eliminated; within the between the surfaces of the femoral head and the hip area steering joint free gap occurs an increase on bone tissue and the Hyalin cartilage cover layer of the Ge  directing up, so a natural, normal joint.

A hip joint distractor is already known (SU-A- 1 251 889), which has a rod attached to one end a device for attachment to the pelvic bone and on the other end to a device for fastening to the upper leg is articulated.

The device for attachment to the hipbone and the one Direction for attachment to the thigh are practical identical. Each of these facilities provides an arch comb, the pointed teeth of which on its concave Side are distributed, while on the convex side of the the combs are rigidly attached, the axes of which in Be tension on the comb ends run symmetrically. It runs the axis of the one intended for attachment to the hip bone NEN comb mounted radially and the axis of the on Attach the comb provided on the thigh Sleeve in its radial plane at an acute angle to the Radius. The rod itself is at one end in the on the Be The sleeve attached to the hip leg is attached to the crest axially adjustable housed. At the other end of the bar a ball head is arranged. In which to attach sleeve attached to the hip bone is now attached a bowl with a spherical recess is inserted, into which the ball head of the rod forms a ball joint can be inserted. In addition, in the both sleeves inserted a compression spring, of which the one between the shell and the respective comb and the other between the stick and the other comb are arranged; both compression springs are used for dynamic ent strain on the hip joint.  

When implanting this hip joint distractor to how The production of the hip joint becomes the one crest on the hip leg in the epiac tabular area and the other on the upper femoral neck arranged in such a way that both sleeves cursed with each other. Here are the sleeves and the rod over the epiphysis in one of the vertical ones Position arranged.

This construction of the hip joint distractor can Only partially reduce the load on the hip joint, the discharge practically only from that during the Er disease-related muscle spasms, their value can be up to 80 kg. On the application of such hips provide treatment methods based on joint distractors basically an alternative to the operations Soft tissues such as the Foss operation of the "hanging thigh".

In addition, arise in the area of fastening the a comb on the femoral neck tension concentrations in the Bone tissue leading to necrosis and destruction of the he sick neck of the femur.

It should also be emphasized that the use of such not fully implanted hip joint distractors leads to the position of the femoral head within the acetabular cup can be kept unchanged, d. that is, it is not possible with this prior art is to set a required joint gap size.

It is also an implantable device for reuse manufacture of hip joints known (GB-A-1 507 953), the serves as a support arrangement for the lower extremity and the Functions of the hip joint to its full relief  the recovery takes over. This known device has a rod that ver absorbs the loads likes that basically the maximum loads on the un correspond to the patient's extremity, and on one End with a thigh fastening device and at the other end with a device for attachment is connected to the hip bone.

The device for attaching the rod to the hipbone and the device for attaching the rod to the thigh are structurally very complicated. Every facility tung has two arcuate elements, which with a End contact each other while the other en which are in opposite directions.

An articulated connection with this rod creates an arch gutter, which is to be inserted over the thigh neck and for receiving a spherical, at one end of the Rod attached head is provided, the head adjustable in the longitudinal direction within the channel and around the Head center is rotatable. The other end of the staff is bent down and with the device for fastening connected to the thigh. This rod protrudes in the implan tated state of the device in front of the thigh out while the arcuate elements of the fastener device on the thigh in the diaphysis. Around sticking it inside the thigh is in the cortical layer has a hole through which the Thigh at the point where the tension concentrates suffer a significant loss of strength.

In this constructive version, it becomes an implant rende device on the thigh "flying" attached where increase the load on the thigh  of the overturning moment. For this reason, the physiological stresses affecting the lower extremity absorbs moving muscle group, in no case the physiological strain on the muscles in a healthy Hip joint, which leads to ver changes the musculature leads. To attach the be implanted device on the hipbone becomes a Milled hole in the hip bone, into which the Bogenele then elements are used that are at two points on Support the hipbone. These arch elements of the facility for Attachment to the hip bone are with a distraction link connected during surgery to Implantation of the device for a change in the Ab stood between the center of the head of the rod and the Bases of the arch elements for setting the requ the desired setpoint of the joint gap. This distrak tion device has a very complicated structure; just the setpoint of the joint gap is set to manoeuvrable, which in turn has a significant duration of surgery brings itself.

In the implantable device for Restoration of the hip joint leads the construction the device for attaching the rod to the thigh due to the basically two contact points with the waiter leg elements having arch elements to weaken the Thigh, for the appearance of a concentration of tension in the contact points and an additional load on the Thigh, which is ne in the treatment results negative effects, resorption of bone tissue and Destabilization of the position of the implanted device brings with it and therefore also the useful life of the be striking devices.

The invention has for its object an implant removable hip joint distractor to restore the hip joints with a device for fastening to the thigh kel and such training indicate that practical no weakening of the thigh bone tissue occurs and behavior and size of the thighs loads during the entire recovery duration of the hip joint close to the physiological, with a healthy lower extremity burdens lie.

The task is solved according to the requirements.

The hip joint distractor implantable according to the invention has a main rod that can withstand loads, which in principle are the maximum values of the lower one Extremity of the patient ingested Bela correspond at one end with an on Direction for attachment to the thigh in connection stands and at its other end at a facility for Attachment to the hipbone is articulated; the implantable Hip joint distractor is characterized according to the invention records that the device for attaching the main rod on the thigh is an additional rod that is used for put in the thigh, principally on the axis of the Diaphysis, is provided and at an angle to the head rod is arranged, which is essentially with the leg neck diaphyseal angle (CD angle) matches.

This simple construction of the implantable hip joint distractor with the device for attachment to the Thigh in the form of the additional rod, which in the upper leg is provided in the diaphyseal axis and reason is additionally arranged at an angle to the main rod,  which ent essentially the femoral neck-diaphyseal angle speaks, is the course of the main staff over the waiter femoral neck, whose axis is basically par allel to the epiphyseal axis lies in a plane through the diaphyseal axis and the center of the joint head goes through; through this arrangement correspond behavior and size of the bela attacking the lower extremity the physiological stresses that a healthy lower extremity. The hip joint becomes full come relieved of what is favorable to his how of manufacturing.

This arrangement of the additional rod on the diaphyses Axes also reduce the relative stress on the bone tissue of the thigh down to values at which inner no pathological changes in half of the bone tissue causing deformations occur more. Within the Range of stress concentration at the contact place the free end of the additional rod with the cortical layer occurs, the thigh remains undamaged and will not be weakened as long as the hole to Insert the additional rod in the cortical layer of the fossa trochanterica located.

Through this device for attaching the main rod on Thigh becomes a rigid fixation of the midpoint of the femoral head inside the acetabular cup and thus also achieving the set value of the Ge steering gap reached.

It is expedient for the implant according to the invention the hip joint distractor the length of the inside the Thigh part of the additional rod housed basic  additionally equal to half the length of the thigh of each patient.

Preferably is also on the additional rod over the length of the part of the thigh to be accommodated within the thigh Auxiliary rod provided a thread to make it easier to insert to allow the additional rod to be placed in the thigh.

According to a further advantageous embodiment, the Main rod of the hip joint distractor via a thread bond connected to the additional rod, whereby an adjuster development of the main rod along its axis is made possible. This will adjust the setpoint of the joint splits significantly in the course of the surgical operation relieved and simplified.

Advantageously, at the end of the main rod on the Side of the threaded connection of the hip joint distractor inner cone aligned with the axis of the threaded connection provided that to determine the main rod in a ge chosen position; the inner cone points over its Length at least three longitudinal grooves; furthermore is a Locking bush provided in this inner cone via a Thread can be screwed.

In order for the hip joint head to come into contact with the hip area Steering pan when bending and unfolding the lower extremity practically completely excluded, are the main rod and the additional rod of the invention Hip joint distractor preferably via a joint connected, the rotation by one in the with the Axes of the main bar and the additional bar common Plane at an angle allows this angle the definition of the axis of this joint at the implant  tion of the hip joint distractor in the position allowed in which they basically through the center of the thigh head of the thigh goes through.

The angle between the hinge axis and the axis of the zu sentence rod lies in the hip joint distractor according to the invention gate preferably in the range of 76 to 90 °.

According to another advantageous embodiment, this is Joint as a plain bearing with a conical bearing surface educated.

The invention is described below with reference to the drawing more detailed explanations; it shows

Fig. 1 An overall view of the hip joint distractor according to the invention with the device for loading attachment to the hip bone and the additional rod in the physiological starting position of the thigh in longitudinal section;

Fig. 2, the section A of Figure 1 on an enlarged scale.

Fig. 3 is a section along the plane III-III of Figure 1 on an enlarged scale.

Fig. 4 shows a section along the plane IV-IV of Figure 1 on an enlarged scale; FIG.

Fig. 5 is a view of the device of Figure 1 from the direction B indicated in Figure 1 with partial Dar position of the main rod.

Fig. 6 is an overall view of an embodiment of the inventive hip joint distractor with the articulated to the device for attachment to the hip bone and with the device for attachment to the thigh in connection with the main rod in the physiological starting position of the thigh in longitudinal section;

Fig. 7 is a section along the plane VII-VII in Figure 6 in enlarged scale.

Fig. 8 is a view of the hip joint distractor of Fig. 6 from the direction C shown in Fig. 6 with partial representation of the main rod and

Fig. 9 is a detailed view of the connection of the main rod and additional rod of an embodiment of the hip joint distractor according to the invention, which represents a joint connection in the form of a plain bearing with a conical bearing surface, in longitudinal section on an enlarged scale.

The hip joint distractor shown in FIG. 1 has a main rod 1, preferably of round cross-section, which can withstand the loads which in principle correspond to the maximum values of the loads absorbed by the lower extremity of the patient concerned. The main rod 1 can consist of a metal or an alloy which is inert to all body media; For this purpose, for example, a titanium alloy identical to the "Vitallium" product can be used. The loads on the main rod 1 can reach values up to 5P, where P is the weight of the patient. In general, the diameter of the main rod 1 is 10 to 16 mm.

The main rod 1 is connected at one end to the device for attachment to the thigh, namely with the additional rod 2 , which is provided for insertion inside the thigh 3 within its medullary channel 5 , the additional rod basically on the axis O of the diaphysis 4th lies. The additional rod 2 is at an angle α to the main rod 1 , the size of which basically corresponds to the size of the neck-diaphysis angle and has a value which is in the range from 120 to 140 °.

The diameter of the additional rod 2 is selected depending on the diameter of the medullary channel 5 in the range from 9.5 to 11 mm.

The additional rod 2 has a length such that its free end reaches the center of the diaphysis 4 . The length L of the part of the additional rod 2 protruding into the interior of the thigh 3 speaks essentially half the length of the thigh 3 ; this is 125 mm for children and 180 mm for adults. Such a length L makes it possible to reduce the relative loads on the bone tissue of the thigh 3 to values at which the bone tissue shows no pathological changes during the entire residence time of the hip joint distractor within the body.

The section 6 of the additional rod 2 located outside the thigh 3 is of somewhat stronger design and is used for connection to the main rod 1 .

The nose part 7 , which is seen at the free end of the additional rod 2 , is pointed to facilitate insertion of the additional rod 2 into the medullary canal 5 . To further facilitate the insertion of the additional rod 2 into the interior of the thigh 3 and for uniform distribution of the loads over its length on the length L of the additional rod 2 to be accommodated in the interior of the thigh 3 , a thread is provided which is preferably milled. The thread is expediently a saw tooth thread with an outer diameter d₁ = 12 mm ( Fig. 2), an inner diameter d₂ = 8.6 mm and a pitch t = 4 mm. In this device for attachment to the thighs 3 ( Fig. 1) a rigid determination of the center point N of the head 8 of the thigh 3 within the acetabular cup 9 of the hip bone 10 and thus also the attitude of the set size of the joint gap 11 in the hip joint is ensured , since the sawtooth thread prevents an axial displacement of the additional rod 2 .

The addition of bar 2 has a connection with the main rod 1, which along its axis O₁ and a setting at a selected location it enables an adjustment of the main bar 1, whereby the adjustment of the joint space 11 we will sentlich facilitated and simplified.

This connection can be realized in a manner known per se. In the embodiment of the hip joint distractor according to the invention shown in Fig. 1, a threaded connection of the ends of the main rod 1 and the additional rod 2 is used, by which an adjustability along the axis O₁ of the main rod 1 is made possible. In the ver strengthened end part 6 of the additional rod 2 , a threaded bore 12 is milled, the axis of which extends at an angle α to the axis O of the additional rod 2 .

For easier adjustment of the main rod 1 , its end protruding from the threaded bore 12 is provided with a pin 13 for a wrench, which also has incisions 14 for screwdrivers.

At its other end, the main rod 1 is connected to a device for attachment to the pelvic bone, which is a joint that enables the rotation of the main rod 1 around a common point S.

This device for fastening the main rod 1 to the hip bone 10 can be designed in a manner known per se. In the embodiment of the hip joint distractor according to the invention shown in FIG. 1, this device is a plate 15 , on one side of which a thickening 16 is provided with a spherical recess 17 into which a spherical head 18 of the joint in question protrudes. The spherical head 18 has a cylindrical shaft 19 which projects into an axial blind hole 20 in the main rod 1 and is clamped there by means of a bracket 21 ( FIG. 3); The bracket 21 lies in an annular groove 22 of the cylindrical shaft 19 and is pushed through two parallel bores 23 provided in the main rod 1 .

The distance between the center of the joint, ie the center S ( Fig. 1) of the ball head 18 and the point of intersection M of the axes O ₁ and O of the main rod 1 and the set rod 2 to the length of the epiphysis 24 between the center N of Head 8 of the thigh 3 and the longitudinal axis of the medullary canal 5 lie in this thigh 3 . The distance SM should also be chosen so large that in the physiological starting position of the thigh 3 between the head 8 of the thigh 3 and the acetabulum 9 of the hip bone 10 when installing the hip joint distractor of the joint gap 11 still maintains its optimal value, which too an increase in bone tissue and to restore the function of the hip joint is sufficient. This value h of the joint gap 11 is set individually in the surgical operation for the implantation of the hip joint distractor for the respective patient by adjusting the main rod 1 in the threaded bore 12 . It should be close to the value of the joint gap of the respective healthy hip joint. To fix the main rod 1 in the selected position, a split pin 25 ( FIG. 4) is provided, which is used in mutually aligned bores which are provided in the main rod 1 and the additional rod 2 . The plate 15 ( FIG. 1) is arranged in the epiac tabular region 26 of the hip bone 10 in such a way that the distance between the points S and L remains as small as possible. Two holes 27 ( FIG. 5) are provided therein for fastening the plate 15 , in which screws 28 or dowels are located in the implanted state. The profile of the plate 15 must ensure a tight fit to the hip bone 10 ( FIG. 1).

The narrow end 29 of the plate 15 is bent towards the hip leg 10 and is in a hole provided during the surgical operation in the hip bone. This results in a rigid fixing of the plate 15 on the hip bone 10 and thus also a fixing of the axis O of the main rod 1 .

In addition, the plate 15 on the hip bone 10 must be set in the position in which the axis O of the main rod 1 in the physiological starting position of the upper leg 3 substantially in one through the axis of the medullary canal 5 and the center N of the head of the upper leg 3 passing level. In this Stel of the main rod 1 development similar to the through the lower extremi recorded loads ty largely to the physiological stresses rule in a healthy hip joint, which is the treatment results affect terms very positive.

This constructive design of the hip joint distractor is extremely simple, does not weaken the bone tissue and enables the union of one of the three axes of rotation of the joint with one of the three main axes of rotation of the hip steering, with the axis of rotation, and because of the Approximation of the center of the joint to the center of the Hip joint also increases the range of motion when rotating around the other two axes, d. H. on the way pull or pull and when bending or Bend apart.

The surgical operation for implantation of the hip joint distraktors will be in the order given below carried out.

First, the length of the epiphysis 24 ( FIG. 1) is determined on the basis of an x-rayogram, according to which the size of the main rod 1 , ie its length or its diameter, and the additional rod 2 are selected.

After the entire preparation of the surgical field for the surgical intervention, which is carried out like the operations for the implantation of conventional implantable devices for therapy of the hip joint, a bore running along the axis of the medullary canal 5 is exposed in the cortical layer of the trochanteric fossa. The additional rod 2 is then inserted into this hole until the thickened end part 6 abuts the thigh 3 . By turning the additional rod 2 is brought into a position in which the axis of the threaded bore 12 lies in the plane passing through the axis of the medullary canal 5 and the center N of the head 8 of the thigh 3 and runs against the epiacetabular region 26 of the hip bone 10 .

The main rod 1 is then inserted into the threaded bore 12 from the lateral side of the thigh 3 .

Subsequently, the cylindrical shaft 19 of the ball head 8 can be assembled with the plate 15 and inserted into the axial bore 20 of the main rod 1 , after which it is inserted into the bores 23 ( FIG. 3) and the annular groove 22 of the bracket 21 .

Further, the main rod 1 by turning on the pin 13 (Fig. 1) along the axis O₁ adjusted towards the hip bone 10 until the plate 15 abuts on it.

Then at the contact point of the cranked narrow end 29 of the plate 15 with the hip bone 10, an opening in the cortical layer thereof is cut out with a bone knife. In many cases, this opening can be cut out to insert the cranked narrow end 29 of the plate 15 using a template are also used to mark the locations at which the holes 27 ( FIG. 5) of the plate 15 are to be made. The cranked narrow end 29 of the plate 15 is then inserted into the opening provided. Then the plate 15 is pressed tightly against the hip bone 10 ( FIG. 1). At the provided Stel len holes 27 ( Fig. 5) in the hip bone 10 ( Fig. 1) for the screws 28 ( Fig. 5) or dowels are then milled through which the plate 15 is attached to the hip bone 10 . By subsequently turning the pin 13 , the set rod 2 is adjusted in the lateral direction along the axis O 1 of the main rod 1 in order to adjust the joint gap 11 , the size of which h is fixed at the distance SM. This distance is determined and recorded individually for the respective patient by x-ray control again and again in the range from 2 to 5.5 mm, which creates the most favorable conditions for restoring the hip joint.

After the adjustment of the joint gap, the clamping of the cylindrical shaft 19 of the ball head 18 takes place within the axial blind hole 20 of the main rod 1 with the aid of the bracket 21 ; furthermore, the main rod 1 itself is fixed within the threaded bore 12 of the additional rod 2 with the cotter pin 25 .

Then the correct employment and effect of the Hip joint distractor still on the operating table below Forced movement of the lower extremity, by way of or pulling, bending together or apart and Rotation, checked.

After completing this review, the surgical Wound with drainage followed by application of a aseptic dressing sewn in layers.

The mobility of the lower extremity is immediate ensured after the surgical operation. The pa tient is allowed to stay three or four days after the operation stand after the pain due to aseptic ent ignitions have decreased. The burden of the operated lower limb, for example, with exercises on one  Exercise bike on the 10th or 11th day after the operation start.

The hip joint distractor works like follows:

The vertical load due to the weight of the patient is transmitted via the articulated connection to the main rod 1 ( FIG. 1) and from this to the additional rod 2 and is divided here over the length L of the section of the upper leg 3 , in the interior of which corresponding part of the additional rod 2 is housed, which has the effect of reducing the relative load on the bone tissue of the thigh 3 to the minimum values at which no deformations occur in this tissue that could cause a pathological change.

The planned arrangement of the main rod 1 the possibility of the hip joint of attacking senkrech th forces and the squeezing effect of Muskula is tur relieve by the presence of the target Gelenkspal tes 11 and thus the favorable conditions provision to restore the hip joint to ensure where the stress behavior on the lower extremity corresponds to the physiological stress in a healthy hip joint.

An increase in the mobility of the hip joint, ie the size of the angular rotatability of the upper leg 3 , is achieved in comparison with previously known implantable hip joint distractors.

With a rotational movement, the angularly adjustable speed of the thigh 3 about the axis SN, which passes through the center S of the spherical head 18 and the center N of the head 8 of the thigh 3 , reaches the full order, which is close to the value of the angularly adjustable of the head a healthy hip joint. The size h of the joint gap 11 remains unchanged in any position.

When the lower limb is pulled away or pulled up, the angular movement of the thigh 3 takes place in the frontal plane, and the center N of the head 8 of the thigh 3 can carry out this angular movement about the center S of the joint connection of the main rod 1 , ie along the circular arc the radius SN, the size of which results from the size of the solid angle of the spherical recess 17 and reaches approximately 40 °. The size h of the joint gap 11 is fundamentally limited by the band length in the hip joint.

When the lower extremity is bent or unfolded, the angular movement of the thigh 3 takes place in the sagittal plane about the axis, which is generally perpendicular to the frontal plane, which passes through the center S of the spherical head 18 along the circular arc with the radius SN, where the deflection occurs the joint connection is not restricted and can reach 90 ° and is only related to the individual structure of the respective hip joint. The size h of the joint gap 11 changes only at the edges of the acetabular cup 9 , while in its central part it remains practically unchanged in every position of the thigh 3 .

In the embodiment of the hip joint distractor according to the invention shown in FIG. 6, the main rod 30 , which can withstand corresponding loads on the lower extremity of the patient, can withstand corresponding loads at one end on the device for fastening to the hip leg 10 with the possibility of rotation by two mutually perpendicular axes and consequently the possibility of win kelbewegung the thigh 3 when pulling or pulling and the rotation of the lower extremity articulated. At its other end, the main rod 30 is connected to the device for fastening to the thigh 3 via a joint which enables the angular movements of the thigh 3 when the lower extremity is bent together or apart.

As a device for attachment in the thigh 3 , an additional rod 31 is used here, which is basically inserted into the inside of the thigh 3 on the axis se of the diaphysis 4 and extends at an angle α with respect to the main rod 30 , which is essentially with the neck dia physen angle corresponds and in its design is the additional rod 2 of Fig. 1.

The articulation of the main rod 30 ( Fig. 6) and the additional rod 31 allows pivoting of the additional rod 31 about the axis in a plane with the axes O₁ and O 'of the main rod 30 and the additional rod 31 common at an angle β to the axis O 'of the additional rod 31 runs ver, whereby in the implantation of the hip joint distractor according to the invention the axis of the articulation of the main rod 30 and the additional rod 31 can be kept in the position in which this axis essentially through the center N 1 of the head 8 of the thigh 3rd goes through.

Due to the hinge connection of the main rod 30 with the to set the rod 31 in this embodiment is an in contact come the head 8 of the femur 3 with the surface of the acetabular cup in each position of the hip joint 3 when folding or bending apart of the lower extremi ty avoided 9, which in turn represent the most important, particularly typical and often executed movements of the lower extremity. By avoiding such contact, the most favorable conditions for restoring the hip joint are created. In this regard, the contraction and spreading movements of the lower extremity when using this hip joint distractor according to the invention take place in a full angular range, which is close to the contracting and spreading angle of the lower extremity in a healthy hip joint, and which can reach 140 °.

In the embodiment of the hip joint distractor according to the invention shown in FIG. 6, the joint connection between the main rod 30 and the additional rod 31 is formed in the form of a slide bearing with a cylindrical bearing surface. For this purpose, a bore 33 is provided in the reinforced section 32 of the additional rod 31 located outside the thigh 3 , the axis of which in a plane common to the axes O 1 'and O' of the main rod 30 and the additional rod 31 at an angle β to the axis O 'of the main rod 31 . This angle β can be in the range from 76 to 90 °. The size of the angle β is selected individually for each patient, for example according to the x-ray of his hip joint. In the bore 33 there is a shell 34 which is rotatably arranged with its cylindri's bearing surface. To limit the axial displacement of this shell 34 in one direction, an annular collar 35 is provided on one side, the outer diameter of which is larger than the diameter of the bore 33 .

In order to limit the axial displacement of the shell 34 in the other direction, a ring 36 is provided on its other side, the outer diameter of which is larger than the diameter of the bore 33 and which is rigidly fastened, for example, with a threaded connection.

The shell 34 is via the threaded connection with the main rod 30 is connected with the main rod 30 along its se Oh O₁ 'is fixedly adjustable and adjustable via the threaded connection. In the shell 34 , a tapped hole 37 is also attached, the axis of which extends at an angle γ to the axis of its cylindrical outer surface, where γ = α-β.

One end of the main rod 30 projects into the threaded bore 37 . To define this main rod 30 in the ge desired position, it has on its axis O₁ 'an inner cone 38 in which a locking bush 39 is attached in a thread. In addition, three longitudinal grooves 40 ( FIG. 7) are milled out along the inner cone 38 , between which three resilient lamellae 41 are formed, which are used to clamp the threaded connection of the shell 34 with the main rod 30 .

The device for attachment to the hip bone 10 ( Fig. 6) is formed in the relevant embodiment of the hip joint distractor according to the invention as a plate 42 , which is similar in shape to the plate 15 , which is shown in Figure 1 Darge; it has two holes through which two screws 28 ( Fig. 8) can be screwed. In contrast to the embodiment shown in FIG. 1, here the plate 42 ( FIG. 6) is articulated on the main rod 30 in such a way that it can rotate under rotation about two axes which are essentially perpendicular to one another in two plain bearings.

For this purpose, two tab parts 43 , 44 ( Fig. 8) are seen before, which are connected at one end via an axis 45 ( Fig. 6) to each other, which is basically perpendicular to that through the axes O 'and O₁' of the main rod 30 or the additional rod 31 going level. The tab part 43 is articulated on the plate 42 at its other end 46 . This end represents an axis which is rotatable within a bore 47 which is provided in the projection 48 of the plate 42 . To avoid axial displacement of the tab part 43 , its end 46 is fixed in the bore by an arcuate pin 49 . The axis of the bore 47 lies in the plane common to the axes O₁ 'and O' of the main rod 30 and the additional rod 31 and is generally perpendicular to the axis S₁.

The other tab portion 44 (Fig. 8) is set (Fig. 6) at its other end via a detachable connection of the Morse taper type in a rigid coupling with the main rod 30 in connection. For this purpose, an inner cone 50 ( FIG. 6) is provided in the tab part 44 ( FIG. 8), in which the end 51 of the main rod 30 is accommodated, which also has a conical shape, its conicity matching that of the inner cone 50 . In addition, in the main rod 30, an axial bore 52 and in the tab part 44 ( FIG. 8) with an aligned threaded bore 53 are seen before, into which a clamping screw 54 is screwed.

The articulation of the main rod 30 with the additional rod 31 is designed in the form of a plain bearing with a conical bearing surface, thereby avoiding any risk of jamming the bearing shell of this bearing. Another embodiment of this articulated connection of the main rod 30 with the additional rod 31 is shown in FIG. 9. A bore 55 is provided in the reinforced section 32 of the additional rod 31 , the inner surface of which forms the lateral surfaces of two truncated cones which are connected to one another at their base surfaces with the smaller diameters. The outer surface of the shell 56 housed in the bore 55 and the inner surface of the bore 55 are congruent. Both surfaces have the same taper. The cone angle of the generatrix of each conical surface with respect to the axis of rotation is in the range from 24 to 36 °. The shell 56 consists of two parts which are connected to each other by a screw 57 .

In this embodiment, the articulation of the main rod 30 with the additional rod 31 ( Fig. 6), it is possible to reduce the dimensions of the reinforced, connecting portion 32 of the additional rod 31 without impairing its load-bearing capacity, which in the treatment of hip joints of children is of particular importance.

The surgical operation for implantation of the hip joint di stractors according to the invention shown in FIGS . 6 to 9 is basically carried out similarly to the surgical operation for implantation of the hip joint distractors according to the invention, as shown in FIGS . 1 to 5.

The assembled with the main rod 30 auxiliary rod 31 is the femur 3 are transferred into the medullary canal 5 (Fig. 6). With the aid of a template, the position of the plate 42 , which is assembled with the tab parts 43 and 44 ( FIG. 8), is marked in such a way that the bores 52 and 53 are aligned ( FIG. 6). The additional rod 31 is returned to its rear end position within the threaded bore 37 of the shell 34 in the direction of the distal end of the thigh.

Thereafter, the plate 42 is attached with the La attached parts 43 and 44 ( Fig. 8) on the hip bone 10 .

With the help of the clamping screw 54 ( FIG. 6), the main rod 30 is connected to the tab part 44 ( FIG. 8). Furthermore, the additional rod 31 together with the thigh 3 by rotating the main rod 30 ( Fig. 6) along the axis O ₁ 'un ter setting the target value h of the joint gap 11 ver. The position of the main rod 30 within the shell 34 is then fixed by turning the locking bush 39 ( FIG. 7).

The embodiment of the hip joint distractor according to the invention shown in FIGS. 6 to 8 also enables a complete relief of the hip joint from vertical loads and from a compression effect caused by the musculature. When to together or apart the articulated connection of the main rod 30 with the additional rod 31 ( Fig. 6) ensures a rotational movement of the lower extremity about a through the center N 1 of the head 8 of the thigh 3 through axis N 1-M 1, which enables that a contact of the head 8 of the thigh 3 with the surface of the acetabular cup 9 in any position of the thigh 3 when bending together and apart of the lower extremity is completely avoided.

The following are examples of clinical use of the hip joint distractor according to the invention.  

Indications of surgical treatment under Ver application of the hip joint distractor according to the invention Restoration of the hip joint were particular dysplastic, degenerative-dystrophic and post-traumatic table hip joint changes in children and adults with the exception of coxarthrosis of inflammatory aetiology. The age of all patients ranged from 4 to 60 years, whereby in these patients a destruction of the Joint ends predominantly existed in the third stage.

As a contraindication, coxarthrosis becomes more inflammatory Etiology viewed. All hip diseases were according to the clinical radiographic characteristics with regard to pathological processes into the following seven groups divided:

• - Congenital luxation of the thigh;
• - dysplastic and degenerative-dystrophic diseases of the hip joint in children with third stage of Destruction of the proximal end of the thigh (Perthesian disease, adolescent epiphyseal solution);
• - coxarthrosis without cystic degeneration;
• - coxarthrosis with cystic degeneration;
• - aseptic necrosis;
• - dysplastic coxarthrosis (in adults);
• - post-traumatic coxarthrosis.

The surgical operation for implantation of the hip joint distraktors was dependent on the biomechanical Initial situation in the hip joint in two versions leads.  

1st variant

The hip joint distractor was without a reconstructive one gripped implanted at the joint ends. In this case a distraction of the hip joint to the required Size of the hip gap achieved. The hip joint capsule was not opened during the implantation.

2nd variant

The surgical operation started with the reconstructive Intervention at the joint ends (corrective osteotomy of the Thighs, for example shaping a roof for the acetabular cup), which is an opening of the joint capsule needed after which the hip joint distractor was implanted de, through which the hip joint is relieved and the setpoint of the Joint gap was set.

In the first variant, the operation lasted 45 to 50 minutes with a blood loss of 150 to 200 ml.

In the second variant, the duration of the Surgery for the amount of time the reconstructive Measures taken, on average 90 to 100 min. The blood losses were 400 to 500 ml.

In most cases, these operations do not require Blood transfusions; however, blood substitutes can also be used be used in an amount of 600 to 800 ml.

The postoperative hospital stay ended average after 15 to 21 days. The seams were removed after 10 days; the spatial movements in bed started walking with crutches without support after 12 days tongue on the leg after 15 to 16 days.  

Then the load on the leg concerned began its axis (with the help of crutches) 5 to 6 weeks after surgery; the transition to walking with fun ornamental stick took place 8 to 10 weeks after the operation Transition to walking without a stick according to individual feelings.

The dwell time of the hip joint distractor in the tissue up to End of treatment ranged from 4 months to 8 years ren. In children (in Perthes disease and adoles central epiphyseal solution) became the hip joint distractor Leave in body tissue for 4 months to 1 year. Within this period was the practically complete recovery Position of the epiphysis of the thigh finished. Both Patients with coxarthrosis of different origins and with The hip joint distractor became aseptic necrosis up to the highest possible rehabilitation and conversion of the Ge left in the body tissue by X-ray was checked. The dwell time depended in these cases the age of each patient, the initial Destruction of the joint ends and the extent of the radio loss of loss. In some cases, the hip joint distraktor even after the healing is finished after per leave the patient's personal wish in the body.

The smallest dwell time of the hip joint distractor was 17 months in this group, the largest 8 years.

All patients could also use the implanted Hip joint distractor work in their field of work or start working.  

example 1

A patient, student, 20 years old, with congenital acetabular luxation of the right hip joint and increasing dysplastic coxarthrosis and second-stage pain syndrome, was implanted in a surgical operation of the hip joint distractor shown in FIGS . 1 to 5 for the restoration of the hip joint. The neck diaphysis angle α was 125 °. When performing the operation, the thigh was first subjected to a subtrohanteric osteotomy between 145 and 125 ° before installing the hip joint distractor according to Zahradnitshek. When inserting the hip joint distractor, a joint gap between 3 and 4 mm was set by the distraction.

4 months after the surgical operation and after 3 months X-rays were used to indicate functional stress New hip formation and complete assembly grow the thigh in the subtrohanteric zone demonstrated at the level of the osteotomy.

9 months after the operation was a practically new hip steered in active form with active load, where get the joint gap size in the range of 3 to 4 mm stayed.

The functional possibilities of the lower extremity and their range of motion can be characterized by the following data be standardized:

Bending or spreading angle 90 to 95 °; Way drawing angle 25 °; Pull-in angle 15 °; Rotation angle in full area.  

After 2 years and 8 months, the hip joint distractor became away; the function of the hip joint was completely like derManufactured.

2 years after removal of the hip joint distractor were in no pathological changes on a control radiograph in the hip joint with practically no restriction Evidence of lower limb strain.

Similar surgical operations were also performed at 10 Patients with congenital dislocation performed. In all Cases have had positive results. Only one the operations resulted in a complication in the form of a Seroms.

Example 2

A hip joint distractor shown in FIGS . 1 to 5 for the restoration of the hip joint of the right lower extremity was implanted in a patient, ballet dancer at the age of 27, with bilaterally deforming coxarthrosis of the cyst shape with a third stage destruction and third stage pain syndrome; the angle α was 140 °.

The surgical operation was carried out without opening the Ge steering capsule of the hip joint. When installing the hip joint the size of the joint space was reduced to one Value set between 1 and 2 mm.

The postoperative period was without complications. The mobility of the hip was 6 months after the operation joints under active strain on the lower extremity practically completely restored.  

The functional possibilities of the lower extremity and the range of motion can be characterized by the following data be standardized:

Bending or spreading angle: 100 °;
Pull-out angle: 15-30 °;
Pull angle: 15-20 °;
Rotation angle: in the full range.

One year after the operation, an x-ray was found Liche contour of the hip joint with a size of the joint gap of 1 to 2 mm.

The hip joint distractor was removed after 3 years; the Right hip function was fully restored produced.

After 1 year, a similar surgical operation was performed Patient's wish also carried out on the left hip joint leads.

Similar operations were performed on 12 patients with coxarthrosis the cyst shape and third stage destruction as well Third stage pain syndrome with positive results carried out. Complications occurred in only two patients through serome formation.

Example 3

The hip joint distractor shown in FIGS. 6 to 8 was implanted in a patient of 7 years with Perthesian disease and a third-degree destruction and pain syndrome in order to restore the hip joint of the lower left extremity; the angle α was 130 °. The joint capsule was not opened during implantation. A joint gap of 3 to 4 mm was set by the distraction.

2 months after surgery and 5 weeks after an active one functional stresses were clearly evident in the past boundaries between the fragments of the thigh head almost completely decreased. All the shoot zone of the epiphysis was clearly evident. The turned posed size of the joint space as well as the position of the The center of the head was unchanged; furthermore failed any features of destabilization of the arrangement.

3.5 months after the operation and 11 weeks after the function neller burden (the child went at this time as before to school and led the usual life) was a prak uniform contour of the epiphysis. In the neck area was the change in the zones of the previous cystic Changes clearly visible. The destruction spots had lost their clear outline and showed one X-ray structure, the structure of a healthy thigh corresponded to kels.

8 months after surgery and 7 months after functional Regeneration was a burden on the treated limb the epiphysis ended, which had regained a contour, that of the shape of the epiphysis of a healthy right hip lenks came close.

1 year after surgery, the hip joint distractor became away. The function of the left hip joint was practical completely restored.  

1 year after removal of the hip joint distractor on a control x-ray the maintenance of a normal size of the joint space and stabilization of the Epiphyseal contour confirmed. There were no restrictions the regulations for the physical activities of the Pa served as part of his lifestyle.

Similar surgical operations were performed on another 9 Pa patients with Perthes disease. In all In some cases, a positive result was achieved. Complications were not found.

Example 4

The hip joint distractor according to the invention shown in FIG. 6 was implanted in a patient of 13 years with an adolescent epiphyseal solution of the head of the left thigh with a second-degree destruction and second-stage pain syndrome; the angle α was 130 °.

The joint capsule was not opened during this implantation net. After the distraction, the joint gap was 12 mm.

3 weeks after the operation, X-rays revealed Search for the following structure: The displacement of the epiphysis was discontinued. The shoot zone was compacted, the curl tion was gone; the destruction site on the thigh kelhals was on the edge of the shoot zone with dense regenerated Bone filled.

Functional 3 months after surgery and 2 months The strain on the lower extremity was the size of the Ge steering gap unchanged. Reach the cervical diaphysis angle te 130 °. 10 months after the operation and after 9 months  a natural functional load became one complete restoration of the femoral head and a clearly condensed contour of the acetabular cup detected. The size of the Joint gap 6 to 8 mm. The epiphysis was complete grown together. The one visible from the x-ray Structure matched the typical structure of the proximal end of the thigh. The functional poss The lower limb operated was in vol given to the extent. The patient could self-sufficient throughout the treatment period went into the School and led the usual life.

1 year after surgery, the hip joint distractor became away. It was a complete anatomical and functional rehabilitation of the hip joint noted.

Similar surgical operations were performed on another 4 Pa patients performed with adolescent epiphyseal solution. All Cases led to positive results. Complications not found.

Example 5

The hip joint distractor according to the invention, shown in FIGS. 1 to 5, was implanted in a patient at the age of 39 who was a professional driver with aseptic necrosis of the head of the right thigh with a third-degree destruction and pain syndrome; the neck-diaphysis angle α was 130 °. The operation was carried out without opening the joint capsule and without any additional surgical measures; the joint gap was set to 6 to 7 mm.

4 months after the operation and 3 months after a do The upper extremity had a strain on the lower extremity femoral head lost its sclerotic structure, being the defect on the roentgenogram shows a shadow structure pointed, which is characteristic of a sponge bone, however was still visible without a clear image.

1 year after the operation, the size of the Joint gap of 5 to 7 mm has been preserved. The Ge steering head was compacted. A restoration of the accounts Nuclear contour was hinted at.

In 4 years the head contour was completely restored with the exception of an almost undetectable margin sections of a size of 0.2 cm × 0.3 cm.

6 years after the operation and after 4 years one used load on the lower extremity was complete eng degradation of the necrotic areas of the femoral head in front; the mass losses of the head were balanced; the Coupling ends of the hip joint were due to the x-ray picture restored. The patient started 1 year and 9 months after the operation with an easier job activity and returned to his nor paint back activity as a passenger car driver.

Similar surgical operations were performed on another 14 Pa patients with aseptic necrosis of the femoral head carried out. In all cases, the results were positive achieved. Complications only occurred in two cases from fistulas on.  

Example 6

A patient at the age of 43, who was an electrician by profession, with post-traumatic coxarthrosis in the form of an old, not furnished, upper rear luxation of the head of the right thigh with tearing off the edge of the acetabular cup and a destruction of the second stage as well as pain syndrome third stage 6 implanted in FIGS to 8 shown Hüftgelenkdistraktor. the angle α was 130 °.

The establishment of the femoral head was in the open Way, d. H. by opening the joint capsule. The distraction resulted in a joint gap of 5 to 8 mm set.

Functional options were possible 15 days after the operation of the lower extremity is completely sufficient the value for active bending was 90 ° and for pulling away 27 °; the rotation was in the normal range.

After 21 days, walking with crutches was unsupported on the extremity and 3 months after the operation a vol le limb strain allowed. The patient could take care of yourself again. The pain syndrome was gone disappear.

The functional possibilities were possible 1 year after the operation excellence. There was no longer any pain syndrome. The joint gap was obtained in the range of 5 to 6 mm remained. The positive change in the structure of the sub chronic region of the femoral head and neck was confirmed. The associated osteoporosis foci were almost completely disappeared, which was previously the main bulk of the  Femoral neck. The contours of the The head and the acetabulum stood out clearly.

1 year and 5 months after the operation, the hip steering distractor removed. There was one on the roentgenogram complete restoration of shape and x-ray determine the graphic structure of the hip joint.

Similar operations were performed on 9 other patients post-traumatic coxarthrosis performed. In all Cases have had positive results. At two Pa fistulas developed.

In summary, it should be noted that the invention Hip joint distractor to restore the hip joint in orthopedics and traumatology for the treatment of patholo conditions that are based on functional disturbances of the hip joint. The invention Adequate hip joint distractor can be used for treatment rative-dystrophic diseases of the hip joint, such as Coxarthrosis of every genesis in different stages of the Disease process, such as dysplasia, adolescent epiphyses solution, cystic dystrophy, aseptic necrosis of the hip steering head, Perthes disease, rheumatic or tubercular involvement of the hip joint, injuries as well about congenital dislocation in children and adults be used successfully. The best success will be however in the treatment of the diseases mentioned in reached their initial stages.

Claims (8)

1. Implantable hip joint distractor, which has a main rod ( 1 ) that can withstand loads that correspond to the maximum values of the loads absorbed by the lower extremity of the patient in question, at one end with a device for fastening to the thigh ( 3 ) is in communication and is articulated at its other end to a device for fastening to the hip bone ( 10 ), characterized in that the device for fastening the main rod ( 1 ) to the thigh ( 3 ) is an additional rod ( 2 ) which can be inserted in the thigh ( 3 ) on the axis of the diaphysis ( 4 ) is seen before and is arranged at an angle (α) to the main rod ( 1 ), which corresponds approximately to the angle of the neck diaphysis (CD angle). 2. hip joint distractor according to claim 1, characterized in that the length (L) of the inside of the upper leg ( 3 ) part of the additional rod ( 2 ) is equal to half the length of the thigh ( 3 ) of the respective patient. 3. hip joint distractor according to claim 2, characterized in that the additional rod ( 2 ) has a thread over the length L, which is preferably milled. 4. hip joint distractor according to one of claims 1 to 3, characterized in that the main rod ( 1 ) with the additional rod ( 2 ) is connected via a threaded connection, which allows an adjustment of the main rod ( 1 ) along its axis (O₁) . 5. hip joint distractor according to claim 4, characterized in that at the end of the main rod ( 30 ) on the side of the threaded connection with it aligned inner cone ( 38 ) is recessed, which has at least three longitudinal grooves ( 40 ) over its length, and one Locking bushing ( 39 ) is provided, which can be screwed into this inner cone ( 38 ) via a thread. 6. Hip joint distractor according to one of claims 1 to 5, characterized in that the main rod ( 30 ) and the additional rod ( 31 ) are articulated to one another via a joint which rotates about one with the axes of the main rod ( 30 ) and the additional rod ( 31 ) common plane at an angle (β) to the axis (O ') of the additional rod ( 31 ) lying axis he enables, the angle β allowing the axis of this joint to be fixed in the position during implantation of the hip joint distractor , in which it passes through the center (N) of the femoral head ( 8 ) of the thigh ( 3 ). 7. hip joint distractor according to claim 6, characterized in that the angle (β) between the joint axis and the axis (O) of the additional rod ( 31 ) is in the range of 76 to 90 °. 8. hip joint distractor according to claim 6 or 7, there characterized in that the joint with a plain bearing is conical bearing surface.