Results covering 20 years use of the cement-free Zweymüller Alloclassic total endoprosthesis of the hip joint.

PURPOSE OF THE STUDY: From an initial group of 206 hips in 190 patients we carried out a retrospective clinical and radiological control of 74 hips in 72 patients covering a period of 20 years. MATERIAL AND METHOD: Indications in 74 operated hips evidenced 48x(64.9%) primary and 26x(35.1%) secondary coxarthrosis. The average age at the time of operation was 53 years (37 years-68 years). All 72 patients with 74 hips received cement-free self- cutting Alloclassic screw cups of pure Titanium together with a cement-free square Alloclassic stem consisting of Titan- Aluminium-Niob alloy according to Zweymüller. Regarding the technique of operation we used the approach after Watson-Jones in the supine position. As prophylaxis against thrombosis 40% of the patients received derivates of heparine and 60% had anticoagulant therapy with cumarine. Prophylaxis against heterotopic ossifications were not carried out at this juncture in our department. RESULTS: After an average post-operational examination lapse of 20 years we were able to examine 72 patients (37.9%) with 74 hips (35.9%) clinically and radiologically. Further classification of the 72 patients records 47 females and 25 males. The average age at the time of operation was 53 years and at the time of post-operational check-up to 74 years. For the clinical post-operational check-up (n=74) we used the Harris Hip Score. Further evaluation shows 12x(16.2%) excellent results, 26x(35.1%) good and 29x(39.2%) fair results. In 7 patients (9.5%) we had to observe poor results because of multimorbidity, although also in these cases stability of TEP had been achieved. The radiological post-operational check-up of the 74 stable hips (35.9%) shows an average excentric position of the head of 1.4 mm (0 mm up until 4 mm) compared with 1 mm after 10 years. Over an average of about 20 years we carried out an exchange of the inlay and the head because of excentric position of the head, which correlates to a rate of reoperation of 6.8%. DISCUSSION: In 2000 and 2001 we published our 10 year results with cement-free Alloclassic screw cup and cement-free stem in 133 hips in 123 patients and compared our findings with those of other authors. After 10 years we saw only 3 % complications with cups and an overall re-operation rate of 6.7%. The 20-year-results show in all cases stable components of both cups and stems. 5 patients (6.8%) had to undergo re-operation with an exchange of inlay and head, whereby the components of the prosthesis themselves turned out to be stable. An average polyethylene abrasion of 1 mm after 10 years compares with a value of abrasion of 1,4 mm after 20 years. The 6.8% rate of re-operation after 20 years indicates the excellent results of the use of cement-free Alloclassic total endoprosthesis system of the hip according to Zweymüller. CONCLUSIONS: The biocompatible qualities of modern prosthesis material lead to a quicker and optimal bony incorporation of the pros- thesis components. The excellent 20-year-results show a broad indicative spectrum, component stability of the prosthesis in all patients and therefore encourage the further use of cement-free hip implants in the future.

[Periprosthetic fractures of the hip]. / Periprotetické zlomeniny v oblasti kycelního kloubu.

PURPOSE OF THE STUDY: It is the aim of our study to present the results of our way of treatment of the periprosthetic fractures, with the cemented as well as the cement-free stems. MATERIAL: From 1.1.1988 until 31.3.2005 we operated 42 periprosthetic fractures of the hip in 41 patients. 31 of our patients were females, 10 of them males. In 22 cases we operated the right side, 18 times the left side and once we had to operate both sides, but at different times. We used the Vancouver classification scale for the grading of the fractures. In our study we excluded type A fractures; we registered 41 type B fractures and one only type C fracture. The reason for periprosthetic fracture in all these 42 cases was definitely a trauma. In 6 cases we found pre-existing loosening of the stem. We have grouped our patients under two headings: 1. Primary cemented stems (n=13) 2. Primary cement-free stems (n=29) The average age at the time of primary operation was 63.6 years in the group of cemented stems and 67.2 years with the cement-free implants. METHODS: The principle of this operation lies in a stable technique of osteosynthesis. If one operates on a stable stem one uses a one and only technique of osteosynthesis. Patients who also suffer from a loosening of the stem, are treated by replacement of the stem combined with a particular form of osteosynthesis. We generally use a transgluteal access with an L-shaped detachment of the Musc. vastus lateralis. In the group of cemented stems (n=13) we carried out a replacement of the stem 6 times and in the group of cement-free stems (n=29) we had to replace the implant on 7 occasions. Analysing the osteosynthesis technique we find the use of titanium cerclages and titanium elements on 35 occasions, in both groups taken together. As implant for the stem we preferred the modulated revision stem according to Zweymüller. Clinical post-operational examination of our patients was carried out according to the Merle d'Aubigne score and two x-rays at different levels. RESULTS: After an average post-operational check-up time of 3 years and 2 months, we were able to examine 8 patients with cemented stems (61.5%), 4 of whom had replacement of the stem by a cement-free implant. In the cement-free group we evaluated 24 patients after an average time of 4 years and 11 months. In this group we had 5x a replacement of the stem, 3x of these we could operate cement-free. The post-operational radiological check showed an excellent building-up of bone structure without any dislocation of the implant in all 32 cases. DISCUSSION: The average age of our patients shows 77 years with those with cemented stems and 74.5 years in the ones with cementfree implants. Analysis of the cemented stems shows a loosening rate of more than 50%, which coincides with the findings of many other authors. After a couple of years using cups of polyethylene we were confronted with the problem of the so-called Polyethylene disease. These alterations may finally lead to a loss of bone quality, to mechanical loosening of the implant and an increase in danger of fracture. When we discuss the group of patients with cement-free stems and compare them to those with cemented ones, we find a number of quite different characteristics. B2 fractures appear in a quite higher number of patients with cemented and loosened stems. In this regard, our own study is congruent with the studies of other authors. In the cement-free group we had 75% B1 fractures with a stable stem. The explanation for these figures is, that the cement-free implants were well incorporated in the bone structure. CONCLUSIONS: The choice of operative procedure when treating periprosthetic hip fractures depends on the type of fracture and the stability of the prosthesis. Our own very positive experiences and the then emerging results lead to a certain strategy in procedure. That means, for us, the use of a cement-free modulated revision stem according to Zweymüller combined with a particular technique of osteosynthesis, using titanium cerclages and titanium elements.

Initial experience using the inverse prosthesis of the shoulder.

PURPOSE OF THE STUDY: The aim of our retrospective study is to show that in cases of very serious degenerative alteration of the shoulder as well as massive Cuff arthropathy, there is a valid reason for the indication of an inverse prosthesis of the total shoulder joint. We therefore describe operation technique as well as evaluation of our own results, including complications. MATERIAL: From October 2000 to October 2005, 24 patients had 25 Delta prostheses implanted. All these 25 implantations were carried out by the author personally, using the Delta prosthesis, in Hybrid technique. METHOD: In all 25 implantations we used a lateral access by splitting the Deltoideus. We implanted the Glenoid component cement free, and we cemented the prosthesis of the Humerus in all our cases. After an average post-operational examination time of 3 years and 9 month, we examined clinically and radiologically, 23 patients (92%) with 24 implants. Pain, mobility and activity in every-day life were considered in the clinical post-operative check up. RESULTS: Evaluation of pain showed that 14 patients (60,9 %) were free from pain and 9 patients (39,1 %) showed a great improvement in their medical state. In all cases we could clearly see that as far as mobility and activity in every-day life were concerned, a significant improvement hat occurred. The post-operative rate of complications showed the figure of 2 luxations (8 %). The luxation of the first patient could be repositioned in a non-operative way. The second patient was reoperated twice and we exchanged the shaft of the Humerus. In no instance did we discover any obstacle to the healing of wounds or any infections. DISCUSSION: When the indication is carefully handled the inverse prosthesis of the shoulder is an excellent way of treatment of serious degenerative alteration of the shoulder joint and major Cuff arthropathy. The operation, which is technically demanding, should only be carried out by an operator experienced in shoulder operations. The rate of luxations can certainly be lowered with the accumulation of experience and strict adherence to the precise way in technique called for by this operation. CONCLUSION: With elderly patients the inverse shoulder prosthesis is a good alternative way of treatment of serious degenerative alteration of the shoulder and massive Cuff arthropathy.

[Long-term results with Zweymuller cement-free Alloclassic stem]. / Langfristige Resultate mit dem zementfreien Alloclassic-Schaft nach Zweymüller.

AIM OF STUDY: The aim of our study is to show the long-term results using the Zweymüller cementless Alloclassic stem. METHOD: In our retrospective study 133 from 206 cases (64.4%) were examined after 10.6 years. The examination was done clinically (Scheme after Merie d'Aubigné) and radiologically. The average age was 72 years (48-92 years) at the time of examination. RESULTS: Intraoperative complications occurred in 3 cases (1.5%), 2 were temporary sciatic-nerve paresis and 1 was a stem fissure. Nine cases had been revised (6.7%). In four of these cases the inlay and the head had to be changed, in two cases mechanical loosening of the cup was found; furthermore, there were one removal of heterotopical ossification and one early infection. Stem problems appeared in only one case with deep infection and had been revised twice. There was neither stem sinking nor mechanical loosening in our series. The average polyethylene wear using a ceramic head with 32 mm diameter was 1 mm after 10.6 years. Clinically excellent results were found in 90% of the cases. CONCLUSION: The long-term results using the cementless Zweymüller stem with a rectangular transversal section and easy operation technique over 20 years are excellent Because of the cortical anchorage and the biocompatible titanium alloy the Zweymüller stem can be used in all femur forms and in different age groups.

[Ten years experience with the cementless alloclassic cup according to zweymüller.]. / Zehnjärige Erfahrungen mit der zementfreien Alloclassic-Pfanne nach Zweymüller.

Because our department of orthopaedic surgery deals with the cementless hip replacement for more than 15 years, we have performed a retrospective study and a critical analysis of our patients. In the time between 01. 05. 1987 and 31. 12. 1989 we implanted 206 primary cement-free total endoprostheses of the hip in 190 patients. After an average time taken for postoperative check-ups of ten years and seven months we evaluated 133 hips (64,6 %) in 123 patients (64,7 %) clinically and radiologically. The clinical postoperative check-up according to the score of Merle d'Aubigne demonstrated very good and good results in 90 % of our cases. After 10,6 years the radiological measurement showed an average polyethylene wear of 1 mm. The critical analysis of our patients amounted to 3 % of cup complications.The therapy with the reoperations of 9 patients (6,7 %) will also be discussed. In the discussion we are concerned with the results and problems of other authors, who are engaged with the cementless hip replacement. Summarizing we can declare, that the cementless Alloclassic cup to Zweymüller has a lot of advantages: ideal primary stability simple surgical technic optimal bony incorporation low polyethylene wear For the future we recommend a change of the headsize from 32 mm to 28 mm. In young and active patients we propose a metal-metal or a ceramic-ceramic pairing. Key words: cementless cup, primary stability, low polyethylene wear, 28 mm headsize.

[Limited indication for percutaneous lumbal nucleotomies.]. / Die enge Indikationsstellung der percutanen lumbalen Nucleotomie und Discoskopie.

The aim of our retrospective study is to show how very circumspect we are to use this method. The clinical symptoms of our patients were lumbalgia or lumboischialgia with or without neurological deficiencies. All these patients were resistent to conservative therapies. We accepted for operation only patients who suffered from protrusions and types of prolaps without perforation of the posterior longitudinal ligament. 179 operations on the vertebral discs were performed in our department between 01. 01. 1992 until 31.12.1997. Of this number 165 (92 %) were conservative nucleotomies (63 females and 102 males) and 14 patients (8 %) hat percutane nucleotomies and discos-copies (6 females and 8 males). The average age at the time of operation was 49 years (from 12 to 81 years) with patients who had an open operation, whilst the patients who had percutane nucleotomy had an average age of 42 years (26 to 56 years). The time span between postoperative checkups was on average about 40 months (3 years and 4 months). The shortest postoperative checkup period was 2 months and the longest 71 months (5 years and 11 months). Of the 14 cases mentioned we operated 9 patients in the segment L4/5, 4 patients in the segment L5/S1 and one patient in the segment L3/4. In 7 instances it was the right side that was injured and 7 times it was the left side which was injured. We performed all operations under general anaesthesia, the patient lying prone on the abdomen with lumbal lordosis raised as much as possible. We always used an X-ray picture enlarger on two planes. As far as subjective pain is concerned, an analysis of the findings gives the following results: 100 % improvement 6 patients, 80 % improvement 2 patients, 50 % improvement 3 patients, no improvement 3 patients. Five praeoperative existing motorial deficiencies had completely vanished postoperatively. As to eventual complications, we had one patient suffering from a lesion at the root of L4 on the right side with postoperative Spondylodiscitis L3/4 who was treated in a conservative way. When patient selection for this method is critically considered, the advantage of endoscopic operation lies in minimal invasion and rapid rehabilitation is associated with it.

[Retrospective study on femoral neck lengthening osteotomy]. / Retrospektive Studie über die schenkelhalsverlängernde Osteotomie.

Our retrospect study refers to the problem of improved flexibility of the hip joint, elongation of the leg as well as decrease of pain. Patients suffering from Coxa vara, a high positioned Trochanter and a short neck of the femur underwent triple osteotomy with a distal transposition of the Trochanter major. All 8 patients had a thorough clinical (according to the scheme by Merlé de Aubigné) and radiological postoperative checkup. The results were analyzed and showed an average increase of the length in leg of 1.9 cm and and average increase of capacity of abduction of 11 degrees. From these findings we draw the conclusion that triple osteotomy operation should be performed only on patients whose hip joints are free from arthrosis or show only insignificant symptoms of arthrosis.

[Plastic operation of the cruciate ligament (part I).]. / Ersatzplastiken des vorderen Kreuzbandes (Teil I).

In the submitted paper the authors describe in the introduction various possible ways of using autologous, homologous and heterologous transplants. A graft taken from the patellar ligament with two bone blocks from the patella and head of the tibia is, because of the great structural strength, the transplant of choice. As far as the surgical technique is concerned, the authors abondoned the open method because of its known disadvantages such as major arthrotomy and associated damage of proprioceptors of the knee joint. The authors are using the semi-open arthroscopic method, whereby artroscopic methods are definitely preferred. Positive aspects of arthroscopic methods are definitely preferred. Positive aspects of arthoscopy such as inspection of the joint, treatment of associated injuries, sparing of Hoffa's body and atraumatic surgical technique all are an advantage for the patient. An obvious advance in the surgical technique is the fixation of bone blocks by interference screws. This leads to early functional treatment using Lennox-Hill's orthesis and full burdening after 3-4 weeks. As most recent animal experiments confirmed that incorporation of the transplant from the lig. patellae is not completed before 12-14 month, it is no advantage to allow the patients to relieve the weight on the extremity. Shortening of the period of treatment reduces also trophic disorders on the operated extremity. Key words: instability of the knee joint, anterior cruciate ligament, plastic operation.

[Plastic Operations of the Anterior Cruciate Ligament (Part II).]. / Ersatzplastiken des vorderen Kreuzbandes (Teil II).

Between January 1, 1988 and December 31, 1993 125 operations of the anterior cruciate ligament were performed in 27 women and 98 men. 58 operations were on the left side, 67 on the right side. In the case - history an injury during leisure time was recorded in 84.8% of the patients, during sports activities in 94%. Of 125 patients 122 were examined by arthroscopy, three were operated by the semiopen approach. The mean age at the time of surgery was 29 years. The selection of the time of surgery indicates that 98% of the patients were operated as early secondary operations and as secondary operations (after 4 weeks). Of 125 patients 122 (97.6%) were examined repeatedly after a mean interval of 43 months. For evaluation the authors used a modification of the "Lysholmscore". According to the latter in 95% very good results were achieved. For evaluation of the stability the authors used a strict test, i.e. the Lachman test and KT-1000 measurements. As to severe complications, they recorded one deep infection, as to late complications there were two cases of arthrofibrosis with "cyclops syndrome". Key words: anterior cruciate ligament, ligamentoplasty.

[Initial experience with arthroscopy of the joint of the hand.]. / Erste Erfahrungen mit der Arthroskopie des Handgelenkes.

In the submitted paper the authors give an account on the development of arthroscopy of the joint of the hand and comments on arthroscopic anatomy and technique of the procedures. In the authors' hospital the procedure is carried out under general anaesthesia, the patient lies on his back with the arm suspended in extension by the fingers, using a 3-5 kg weight. The authors use a needle arthroscope of Storz Co. with a diameter of 2.7 mm which is inserted into the joint from a dorsomedial approach. During the period between Jan. 1, 1990 and Dec. 31, 1993 14 arthroscopies of the joint of the hand were made in 10 women and 4 men, three times on the left and 11 times on the right hand. The mean age of the patients was 25 years and the mean follow-up period 2 years (8 months - 3 years). Revealed surgical findings: - chondromalacia 7 times; - damage of the disk twice; - rupture of the disk and chondromalacia 3 times; - synovitis once; - no pathological intraarticular finding once (cysta lunata without perforation). By surgery with irrigation and arthroscopic procedures such as resection of a ruptured disk and elimination of a defect of the authors were able to achieve improvement in mor than 70% of the patients.

[Experience with dynamic hip screw in retrochanteric and subtrochanteric fractures of upper femur.]. / Erfahrungen mit der dynamischen Hüftschraube bei per- und subtrochantären Oberschenkelfrakturen.

From 1st January 1988 to 31st December 1994, 105 patients were given 106 dynamic hip-screws in the Orthopaedic Department of the Public General Hospital, Zwettl. The average age at the time of operation was 77.6 years and the time lapse between the accident occuring and the operation performed was on average 31 hours. In 94.3% of the cases we could perform a closed reduction and in 88.7% we used a 135 degree-DHS. The four-hole plate dominated in 73.6% of the plates used. Internal complications totalled 23.6% out of which 9.5% of the patients died during their hospitalization. Here one must take note that the patients who died were of advanced age and multimorbid. We carried out clinical and radiological postoperative examinations on 54 patients (51.4%) with 55 operations (51.9%). The postoperative examinations took place on an average of 33 months (2 years and 9 months). The clinical postoperative examinations were carried out according to the Merle D'Aubigne system - 29 excellent, 58 good and 13 poor. The radiological postoperative examinations disclosed an ossian consolidation of 100% for 54 patients with 55 operations. Taking into account the classification of fractures according to the AO we find that the DHS is mainly used to treat fractures A 1/1-, A 1/2- and A 2/2-. With the exception of subtrochanteric fractures in which we have lately been using the Gamma-Nail, we have the DHS as a technically relatively simple and inexpensive implant in the treatment of pertrochanteric fractures of the neck of the femur.

[Reconstruction Osteotomy by Morscher's Method in Coxa Vara.]. / Rekonstruktionsosteotomie nach Morscher bei Coxa vara.

Between January 1, 1989 and December 31, 1994 the authors performed in eight patients prolongation osteotomy of the neck of the femur with transposition of the greater trochanter. The patients comprised six women and two men, in four instances the left and four instances the right side was operated. The indications comprised in four patients congenital dysplasia of the hip joint with a shorter externity, is three patients Perthes disease, incl. in one patient postluxation m. Perthes, in one patient a state following fracture of the cervix. By Morscher's osteotomy prolongation of the extremity can be achieved and improved biomechanics of the hip joint. The method is recommended especialy younger patients with mild arthritic changes.

[Long-term results of implantation of polyethylene screw sockets using Edler's method]. / Langfristige Resultate der Polyäthylenschraubpfanne nach Endler.

High-molecular polyethylene is used in many technical spheres and in orthopaedics it is used in particular as a sliding component. In orthopaedic endoprosthetics it serves as a material for the manufacture of sockets, whereby polyethylene sockets can be anchored with our without cement. Morphological research corroborates the suspicion of inadequate static firmness of the polyethylene used and this may lead to abrasion and thus mechanical loosening of Endler's screw socket and subsequently also of the metal shank. At the orthopaedic department of the General hospital in Zwettel (Austria) between 1984 and 1987 113 Endler sockets were implanted in 101 patients. So far 41 reoperations were made in 39 patients. In 71% of the patients replacement by a non-cemented socket according to Zweymüller followed, in 17% by a cemented socket according to Müller. In 4 joints at the same time also the femoral component had to be replaced, in 13 shanks bone rarefaction in the area of the calcar femoris was detected. In shanks with removable heads the head was always replaced. Clinical evaluation of the operated patients was done according to the procedure of Merle d'Aubigné.

[Retrospective study of heterotopic ossification with and without prophylactic indomethacin therapy]. / Retrospektive Studie über heterotope Ossifikationen mit und ohne Indometacinprophylaxe.

The authors evaluate the problem of heterotopic ossifications as a complication of total endoprostheses of the hip joint. The classification into stages as elaborated by Arcque was used and compared with the clinical correlate. The authors compared the year 1989 when the total number of prostheses was 150 without prophylaxis of ossifications, with the year 1992 when the total number of endoprostheses was 200 with prophylaxis. In 94% of the patients starting on the second day after surgery to the 21st postoperative day 2 x 50 mg Indomethacin (2 x 1 capsule Indocin forte) were administered. As a gastroprotective drug the patients were given Ranitidine, 2 x 150 mg (2 x film tablets Zantac 150). Complications such as gastrointestinal complaints and skin exanthemas were observed only in 6 patients. Prophylaxis of thromboembolic disease was used in 1992 in 65% of the patients by anticoagulants and in 35% of the patients by administration of low-molecular heparin. This procedure proved a very simple, effective and safe method for prevention of para-articular ossifications: [table: see text]

[Initial Experience with a New Generation of Zweymüller's Endoprosthesis.]. / Erste Erfahrungen mit der neuen Generation der Zweymüller-Totalendoprothese.

In the first part of our paper innovations as regards the non-cemented endoprosthesis of the hip joint by Zweymüller's method are described. As a special advantage the double cone of the socket is mentioned which as to its anatomical shape is close to the acetabulum and makes only slight resection of the bone on the floor of the acetabulum possible. At the Orthopaedic Department of the hospital in Zwettl between 1984 and 1987 more than 100 polyethylene Endler screw sockets were implanted. From the end of 1987 to the beginning of 1993 the authors used non-cemented endoprostheses as designed by Zweymuller. Based on the mentioned advantage of the new biconical socket, as suggested by Zweymuller, the authors implant this generation since the beginning of 1993. During the period from Jan.1, 1993 to Dec. 31, 1993 68 endoprostheses of the hip joint of the new type were used during primary operations. The follow-up of patients respected clinical and radiological criteria (pattern of Merle d'Aubigne). Of 68 patients 67 (98.5%) were followed up. In the present retrospective study in particular heterotopic ossifications were investigated, whereby the years 1992 and 1993 were compared. Key words: non-cemented total endoprosthesis of the hip joint, non-cemented biconical socket.

[Initial experience with percutaneous lumbar nucleotomy and discoscopy.]. / Erste Erfahrungen mit der percutanen lumbalen Nukleotomie und Discoskopie.

Ever since percutaneous lumbar nucleotomy and discoscopy were introduced great hopes in this method were raised by specialists and patients. Based on the initial euphoric comments in the professional press, the authors started to use this procedure in 1992. During the period between Jan. 1 1992 and Dec. 31 1993 at the orthopaedic department of the General Hospital in Zwettel 69 operations of the disc were performed. The number comprised 62 conventional nucleotomies and 7 percutaneous nuc-leotomies combined with discoscopy. The mean follow-up period in patients with percutaneous nucleotomy and discocopy was 14 months (3-24). With regard to preoperative and postoperative development the therapeutic results were evaluated as follows. The authors proved strictly limited indications of this new surgical method and its inclusion in the therapeutic plan in protrusion and prolapse of the disc. As revealed by analysis, this method can be used to extend the hitherto valid therapeutic spectrum, if strictly limited indications are used. Key words: percutaneous nucleotomy, discoscopy.

[Arthroscopic treatment of lateral dislocation of the patella.]. / Arthroskopische Therapie der lateralen Patellaluxation.

Between Jan. 1, 1988 and Dec. 31, 1993 at the Orthopaedic Department of the hospital in Zwettl 12 patients with lateral dislocation of the patella were operated arthroscopically. In two habitual, in 10 relapsing and in one a new dislocation of the patella was involved. The patients were followed up clinically and radiologically, the mean follow-up period being 47 months. Every patient was subjected to complete arthroscopic examination of the knee joint. In the final stage of diagnostic arthroscopy an optical instrument was introduced from a medial retropatellar approach and lateral release was carried out. Subsequently from a 1.5 cm skin incision in the area of the medial facet of the patella a needle with a loop from the instrumentarium for sutures of the meniscus was inserted and from a medial parapatellar approach at both ends a PDS fibre, grade 0, was pulled out and by this thus developed U-shaped stitch medial capsulorrhaphy was achieved. In this way a total of 5-7 stitches were made. Extension of the U-stitches revealed on arthroscopy a satisfactory medialization of the patella. Further treatment involved application of a plaster tube in extension for 4 weeks: The authors discuss in the submitted paper the surgical technique and clinical and radiological results. Key words: dislocation of the patella, arthroscopy, lateral release.

[Complications after replacement of a knee joint endoprosthesis with a cementless "low contact stress" prosthesis]. / Komplikationen nach endoprothetischen Ersatz des Kniegelenkes mit einem zementfreien Modell Typ LCS.

Total endoprosthesis of the knee joint of the LCS type reduce due to the mobile placement of the menisci and rotatable components the mechanical demands on anchoring in bone and thus contribute to satisfactory biological integration. During the period between June 1, 1989 and December 31, 1991 in the orthopaedic department of the general hospital in Zwettel 41 patients had 42 total endoprostheses (LCS) of the knee joint implanted. The group comprised 34 women and 7 men. All patients were checked and evaluated according to Hungerdorf's schema. The age range was 62 to 79 years with an average of 65.8 years. The follow-up period was 8 to 38 months, mean 21 months. The results as regards pain, stability, mobility, axis of the extremity and ability to walk were evaluated as very good and good. The authors discuss also postoperative complications. They did not observe loosening of cement-free components.