[Total hip arthroplasty with shortening subtrochanteric osteotomy and custom-made prosthesis in Crowe type IV developmental dysplasia]. / Versorgung der hohen Hüftluxation (Crowe-IV-Hüfte) mit einer zementfreien Individualendoprothese und z-förmiger subtrochantärer Femurverkürzung.

AIM: Total hip arthroplasty in patients with a Crowe type IV developmental dysplasia is a technically demanding procedure with a higher complication rate compared to a standard total hip replacement. Specific anatomic features and the necessity of a femoral shortening osteotomy are the reasons for more complications. In this retrospective study we intended to find out whether the use of a custom-made stem based on a CT scan will lead to a better outcome including a lower complication rate. MATERIAL UND METHOD: From 2003 to 2010 we implanted a cementless CTX® individual stem in combination with a subtrochanteric Z-shaped shortening osteotomy in 25 patients with a high hip dislocation, four of them were men (one bilateral) and 16 women (four bilateral). Mean age of the patients was 44.6 years. In all cases the cup was implanted at the level of the anatomic hip centre. Patients were followed with a clinical and radiographic assessment. The morphology of the femur was analysed by CT scans. RESULTS: The average amount of femoral shortening was 3.4 cm (max. 4.2/min. 2.6 cm). Lengthening of the leg was achieved with an average of 3.8 cm (max. 4.4/min. 3.2 cm). The remaining leg length discrepancy was 0.8 cm (max. 1.2/min. 0.4 cm). In none of the cases did an intraoperative fracture of the femur occur, either in the proximal or in the distal part of the femur. Enlargement of the intramedullary canal was not necessary in any case. The planned depth of the prosthesis could be achieved in all patients. We did not observe any problems with wound healing in our patients. The average Harris hip score was 90 (83 up to 100). Additional cerclage wires are not necessary with this technique when the osteotomy is well adapted. After complete healing the osteotomy can just be noticed by a certain hypertrophy of the cortical bone. In our cases we had a complication rate of 16 %, significantly lower in comparison to literature values. CONCLUSIONS: Total hip arthroplasty in type IV developmental dysplasia with a custom-made stem based on a CT scan is a procedure that respects the special anatomic features preoperatively und is able to correct the deformity with the individually manufactured prosthesis. High femoral anteversion is corrected at the level of the neck of the stem. There is no necessity for a derotation at the level of the osteotomy. The osteotomy is stabilised by the Z-shape and through a perfect intramedullary fit of the stem. The anatomic shape of the subtrochanteric region is perfectly suitable to perform a femoral shortening.

Does tibial rotation correlate with femoral anteversion? Implications for hip arthroplasty.

The aim of the study was to assess the magnitude and variability of rotation of ipsilateral femur and tibia and to identify the existence of rotational correlations. Femoral rotation (FR) and tibial rotation (TR) were measured with computed tomography in 151 consecutive patients when total hip arthroplasty was planned. Median FR was 14 degrees (range, -23 degrees to 91 degrees ) and median TR was 38 degrees (range, 15 degrees -76 degrees ). Femoral rotation was significantly higher in females, in left femora, in the presence of secondary osteoarthritis, and in hip dysplasia. Tibial rotation was significantly higher in females. Femoral rotation and TR positively correlated (r = 0.2963, P = .0001). The magnitude of TR and FR was found to be dependent on each other. Disregarding the variability and magnitude of TR may result in asymmetrical foot positioning after correction of FR during total hip arthroplasty.

[Good results with a cemented titanium stem after 7-9 years]. / Zementierter Titan-Schaft erbringt gute Ergebnisse nach 7-9 Jahren.

AIM: Because of partially ver y controversial results in cemented hip stem replacements made of titanium alloy we investigated in our own patients the mid-term survival of the "Euroform"-stem. This stem is anatomically designed for cemented fixation, made of Ti (6)Al (4)V. METHOD: Within a period between 1990 and 2000 we implanted 2,141 Euroform-prostheses. The course of 103 patients which were operated between April 1990 and April 1992 was followed up. 9 patients died in the meantime and 8 could not be reached. Of the remaining 86 patients we could examine 73 patients with 79 prostheses (87 %). Investiagtion included a questionnaire and clinical and radiological examination to create the Harris-hip-score. The follow-up was 7-9 years, with an average of 94 months. RESULT: Of those 79 prostheses, revision surgery was performed for septic loosening in three cases and for aseptic loosening in two cases. Radiologically one stem was found to be loosen. This means that for aseptic loosening we had a revision rate for aseptical femoral loosening of 2.5 % after 94 months with a mean Harris-hip-score of 84 points. Good or excellent results were found in 82 %, fair results in 9 % and poor results in 9 %. CONCLUSION: The "Euroform" prosthesis is a cemented titanium alloy stem that has in contrary to some other published studies good mid- to long-term results.

[Assessment of implant position of CTX-custom-made stems with EBRA-FCA in 107 cases of total joint replacement]. / Bewertung der Implantatposition von 107 individuellen CTX-Hüftendoprothesenschäften mit EBRA-FCA.

AIM: The aim of this study was to assess the ratio of correct and malpositioned stems in a THR population with custom-made stems. Furthermore, any relation of the extent of deviation from the exact stem position and defined patient variables was evaluated. METHODS: Preoperatively, in three-dimensional virtual reality, CTX-individual hip stems were positioned in femora reconstructed from the individual patient's CT data until a stable cortical fit was achieved. Postoperative femoral stem position was measured with EBRA-FCA (EinzelBildRontgenAnalyse-Femoral Component Analysis). Differences of planned and actual depth of stem position were calculated for 107 CTX-custom-made hip stems implanted at one institution. RESULTS: Compared to preoperative planning 59 hip stems were placed too high, while 16 were placed exactly to within one millimeter and 32 were positioned too low. Deviations of postoperative stem position from preoperative planning did not correlate with previous femoral osteotomy found in one-third of femora or femoral anteversion exceeding 25 degrees as present in two-thirds of patients. CONCLUSION: In 71 % the intraoperative stem position did match the preoperative CTX-implant fitting into virtual patient femora. 29 % of implanted stems were malpositioned, i. e., deviations were greater plus or minus 5 mm to preoperative computer planning. None of the examined variables such as body mass index, previous femoral osteotomy, surgical approach, abnormal anteversion angle served as a predictive value for CTX-stem position in this cohort.

[Functional results following Girdlestone arthroplasty]. / Funktionelle Ergebnisse sekundärer Girdlestone-Hüften.

AIM: Aim of the investigation was to identify prognostic factors predicting the level of postoperative function following Girdlestone ("G")-arthroplasty. METHODS: Data were derived from 87 patients, 90 hips, treated with "G"-arthroplasty at one institution between 1983 and 2000. RESULTS: Hip scores amounted to 38.7 (HHS) and 3.5 (Merle) points. The number of previously implanted total hip arthroplasties (THR) did not correlate with the functional result of "G"-arthroplasty (r = - 0.1400; p = 0.4524). On average, the duration of THR prior to "G"-arthroplasty was 44.6 months. Survival time of the latest THR and function of "G"-arthroplasty did not correlate (r = 0.0705; p = 0.7065). Patient age at primary THR, at follow-up, or at "G"-procedure did not correlate with HHS (r = - 0.0367, p = 0.8418, r = 0.1527, p = 0.4121; r = - 0.0151; p = 0.9356, respectively). Time following "G"-arthroplasty, averaging 90.6 months, did not correlate with patients function (r = 0.0920, p = 0.6289). Revision following "G"-procedure and the presence of diabetes positively correlated (p = 0.0104). The appearance of cement in the femoral canal and radiographic signs of persistent bone infection correlated significantly (p = 0.0572). CONCLUSION: Patient age, duration of "G"-hips, and number of prior THR were not reliable to predict the function of "G"-arthroplasty.

Transoral decompression, anterior plate fixation, and posterior wire fusion for irreducible atlantoaxial kyphosis in rheumatoid arthritis.

STUDY DESIGN: Fifteen consecutive patients with irreducible atlantoaxial kyphosis caused by rheumatoid arthritis were treated by combined transoral odontoid resection, anterior plate fixation, and posterior wire fusion. OBJECTIVES: To investigate the clinical results of this new surgical procedure. SUMMARY AND BACKGROUND DATA: Irreducible atlantoaxial kyphosis in rheumatoid arthritis results from a destruction of the craniocervical joint ligaments and the anterior aspects of the lateral atlantoaxial joints. The development of a paradental synovial pannus and atlantoaxial joint impaction prevents reduction by conservative treatment, such as skull traction. Posterior surgical procedures for the treatment of the irreducible atlantoaxial kyphosis with spinal cord compression have been associated with high morbidity and mortality. METHODS: Fifteen consecutive patients were treated by transoral odontoid resection. The fixation was performed with anterior plating, according to the method of Harms in combination with posterior wire fusion according to Brooks. Before and after surgery, evaluation was performed using the parameters of pain (visual analog scale), range of motion, and subjective assessment of improvement and the Health Assessment Questionnaire. The neurologic deficit was defined according to the classifications proposed by Ranawat, Frankel, and Nurwick. Plain radiographs, including lateral flexion and extension views, and magnetic resonance scans were obtained. RESULTS: No perioperative fatality occurred. The average clinical and radiographic follow-up was 50.7 +/- 15.6 months (range, 26-77). Postoperative pain was relieved (mean pain score before surgery, 7.9 +/- 1.87; after surgery, 3.8 +/- 1.27), and the range of motion of all patients increased (mean 21.5 +/- 14.0 degrees for rotation; mean 17.2 +/- 5. 54 degrees for bending). The score on the Health Assessment Questionnaire increased in three patients, remained unchanged in three and decreased in six patients (three had died). All patients improved at least one Ranawat level after surgery, except a patient in Ranawat Class II, whose condition remained unchanged. All patients were satisfied with the procedure and reported subjective improvement. CONCLUSION: Transoral plate fixation combined with posterior wire fixation after transoral odontoid resectionis an effective, reliable, and safe procedure for the treatment of irreducible atlantoaxial kyphosis in rheumatoid arthritis.

[Computer-assisted prosthesis selection and implantation control]. / Computergestützte Prothesenauswahl und Implantationskontrolle.

Using CT-based 3D-data of human femora, it is possible to simulate the THR very realistically by a newly developed fit program. The evaluation of OP simulations of different prostheses systems on more than 200 femora showed that a large number of hip joints can only be reconstructed unsatisfactorily by standard stems regarding intramedullary fit and joint geometry. This could be minimized by optimized off-the-shelf prostheses, but there is still a remainder that can only be satisfactorily reconstructed by customized devices. The decision of choosing a standard or custom device for each individual case can be made by the same fit program using CT-data of the femur. Planning with conventional X-rays only shows major restrictions. With the results of our evaluation, "standard stems" have been developed respecting the fixation principles of our CTX-custom device system and with optimized head positions using statistical methods. The selection of the right size regarding the criteria of fixation and joint geometry is examined preoperatively with the help of the same fit program. If standard prostheses cannot fulfill the requirements, we see the indication for a custom-made stem. In this way the quality of custom-made prostheses can be transferred to the application of standard devices. The operative results confirm our expectations of the exact planning and implantation technique. The CTX combination system consisting of off-the-shelf stems and customized devices will reduce the costs for optimized techniques. In comparison with other new 3D-methods like robotics or navigation, our development has an advantage: this technology including the fit program is accomplished preoperatively in order to simplify the operative technique. In future, combinations of our advanced planning methods as well as implantations of custom prostheses using navigation systems and/or robotics seem to be possible and may be helpful for special cases.

[Individual cement-free total hip endoprosthesis in a patient with a rare form of dwarfism (Fuhrmann syndrome)]. / Individuelle zementfreie Hüft-TEP bei einer Patientin mit einer besonderen Form des Minderwuchses (Fuhrmann-Syndrom).

We present a single case study of a 47-year-old female patient with a rare form of primary dysostotic dwarfism. This syndrome was first described by Fuhrmann in 1972. Seven years ago, this patient underwent bilateral cementless total hip arthroplasties for severe osteoarthritis about her hips. Custom-made components were used. While achondroplastic patients present with wide femoral medullary canals, it is clinically relevant that Fuhrmann Syndrome features narrow femoral medullary canals. This complicating anatomical factor in Fuhrmann syndrome as well as the increased anteversion angles were overcome by the use of CAD stems. We conclude that the custom-made stems, although in our case measuring half the size of the smallest commercially available design, have proved to be durable and able to withstand physiological loads at follow-up period of 72 months.

[Can meniscus refixation prevent early development of arthrosis in the knee joint? Long-term results]. / Kann die Meniskusrefixation die frühzeitige Arthroseentwicklung im Kniegelenk verhindern? Langzeitergebnisse.

This retrospective study presents the long-term results after meniscal repair with emphasis on early-development of osteoarthritis in the knee. From 1984 to 1996 meniscal repair using the inside-out technique was performed on 54 patients. 25 patients had an isolated tear of the meniscus and 29 additionally a tear of the anterior cruciate ligament (ACL, combined injury). 18 patients of those with a combined injury showed a stable knee during clinical follow-up. A separate evaluation of this group was carried out. The mean follow-up was 6.4 years. 22 patients were examined over a period of 2-5 years (mean 3.5) after surgery, 32 patients after 5 years (mean 8.9). The clinical evaluation was carried out using IKDC, Tegner activity scale, Lysholm, and Tapper and Hoover-Score as well as the Fairbank radiographic evaluation. According to the Fairbank's evaluation the results show that up to 5 years after meniscal repair only minimal radiographic changes were detectable. In only 21% of patients with an isolated meniscal lesion and in 13% of those with a stable knee after a combined injury beginning of osteorathritic changes were noted more than 5 years postoperatively. Early osteoarthritic changes were present within 5 years after surgery in non-stable knees (untreated rupture, suturing). Patients with meniscal repair mostly regain their original Tegner activity level and good to very good results in the clinical scores. However, the results clearly indicate that the success of meniscal repair depends on the stability of the knee. Thus, meniscal repair in stable knees is recommended to prevent early development of osteoarthritis.

Biomechanical assessment of transoral plate fixation for atlantoaxial instability.

STUDY DESIGN: In an experimental study using human cadaver specimens the biomechanical data of anterior atlantoaxial plating according to Harms were evaluated. OBJECTIVES: The purpose of this study was to evaluate this method biomechanically. SUMMARY AND BACKGROUND DATA: The optimum fixation method to achieve fusion at the atlantoaxial joint after odontoid resection is still a matter of discussion. Isolated posterior surgical procedures for treatment of irreducible atlantoaxial kyphosis with spinal cord compression are associated with high rates of morbidity and mortality. Transoral atlantoaxial plate fixation has been designed by Harms as a fixation technique after odontoid resection. In a modification, this procedure has been combined with the posterior wire fusion according to Brooks. METHOD: Eight human cadaver craniocervical specimens were tested in flexion, extension, rotation, and bending with a nondestructive flexibility method using a nonconstrained testing apparatus. Five different groups were examined: 1) control group (intact); 2) unstable group (after dissection of the atlantoaxial ligaments and odontoidectomy), 3) Harms group (transoral atlantoaxial plate fixation) 4) Harms-Brooks group (transoral atlantoaxial plate fixation and dorsal atlantoaxial wire fixation); and 5) Magerl group (transarticular atlantoaxial screw fixation). In a second experimental series, failure loads of the Harms-Brooks and the Magerl fixation methods were determined. RESULTS: The angular displacement of the Harms-Brooks group and the Magerl group was less than in any other group. Stiffness values at 0-3.0 Nm loads in any direction were larger for the Harms-Brooks-and Magerl-fixated specimens than for the Harms, control, or unstable specimens. No statistically significant difference was observed between Harms-Brooks and Magerl reconstruction stiffness. Ultimate failure load in the Harms-Brooks group was higher than in the Magerl group. CONCLUSIONS: Experimentally, isolated anterior atlantoaxial plating was less stable than the combined reconstruction procedures. Transoral plate fixation according to Harms in combination with posterior wire fixation according to Brooks provided a failure load and stiffness equal to transarticular screw fixation according to Magerl.

Arthroscopic labrum refixation for post-traumatic anterior shoulder instability: suture anchor versus transglenoid fixation technique.

SUMMARY: The aim of this retrospective study was to compare recurrence rates following transglenoid labrum refixation or fixation using the suture anchor (FASTak, Arthrex, Naples, FL) technique. Additionally, parameters that apparently influence the rate of redislocation were investigated. There were 163 patients with post-traumatic anterior shoulder instability treated with an arthroscopic labrum refixation; 108 patients (66.3%) were stabilized with the transglenoid suture technique (group I) and 55 patients (33. 7%) with the suture anchor (FASTak) technique (group II). The average follow-up was 4.5 years (range, 2.0 to 7.9 years) in group I and 3.2 years (range, 2.0 to 5.0 years) in group II. The Rowe score increased from a preoperative average of 35.0 points in group I and 35.4 points in group II to a postoperative average of 68.3 points in group I and 84.6 points in group II (P <.01). There was recurrence in 35 patients (32.4%) in group I and 9 patients (16.4%) in group II (P <.05). All incidents of redislocation occurred during the first 21 postoperative months; 58.4% of the patients (n = 63) in group I and 16.4% of the patients in group II (n = 9) had to reduce their sporting activity (P <.001). Independent of the type of surgery, there was a significant correlation of the postoperative rate of redislocation and age (P <.001), number of preoperative dislocations (P <.01), and degree of labrum lesion (P <.001). No correlation with the rate of redislocation was shown for gender, handedness, dislocation-operation interval, degree of Hill-Sachs lesion, or number of transglenoid sutures or anchors. Concerning post-traumatic anterior shoulder instability, the arthroscopic labrum reconstruction with the suture anchor (FASTak) technique was superior to the transglenoid technique but has not yet achieved the level of success obtained by open surgery. With fewer than 5 preoperative redislocations after a first traumatic shoulder dislocation, the arthroscopic treatment is recommended. In cases of more frequent preoperative dislocations, open surgery in combination with a capsular shift should be performed.

[Migration analysis of cemented Müller polyethylene acetabular cups versus cement-free Zweymüller screw-attached acetabular cups]. / Migrationsanalyse zementierter Müller-Polyethylenpfannen versus zementfreier Zweymüller-Schraubpfannen.

OBJECTIVE: Is the cementless Zweymüller hip cup superior to the cemented Müller cup? METHOD: This article presents a radiographic analysis of 25 cemented Müller acetabular cups versus 22 cementless Zweymüller cups using the Einbildröntgenanalyse (EBRA), a software tool for radiographic measurement of acetabular cup migration. In addition, we determined the effects of the cup anteversion and inclination, the polyethylene wear, the lateral bone coverage of the acetabular cup, the position of the center of rotation, and individual factors on the incidence of cup migration. RESULTS: The incidence of cup migration was 64% in the cementless group and 48% in the cemented group after a mean follow-up of 6 years. The average migration rate was 0.33 mm/a for cementless Zweymüller cups and 0.38 mm/a for cemented Müller cups. Cup anteversion and inclination showed no effect on the incidence of cup migration. The combination metal-polyethylene (0.17 mm per year) demonstrated a significantly higher wear rate in comparison to the ceramic-polyethylene combination (0.11 mm per year). Incompletely lateral covered cups demonstrated a significantly higher incidence of cup migration. Cranial or medial deviations of the center of rotation up to 5 mm are tolerable, in contrast to caudal or lateral deviations that lead to a significantly higher incidence of cup migration. CONCLUSION: The superiority of the cementless Zweymüller cup was not observed. We recommend a complete lateral bone coverage of the hip cup. Cranial and medial deviations of the center of rotation up to 5 mm are tolerable. In the present study the polyethylene wear of the ceramic-polyethylene combination was significantly less as compared with the metal-polyethylene combination.

Hip and knee replacement after longstanding hip arthrodesis.

This study determined whether patients with severe knee disease below a hip arthrodesis can be treated successfully with total knee replacement alone or whether such patients require total hip arthroplasty followed by knee replacement. Eighteen patients who had hip arthrodesis for a mean of 33 years underwent total hip replacement alone, total knee replacement alone, or a combination of both. The Harris hip score improved from a mean of 55.3 to a mean of 86.9 points at 45 months after total hip arthroplasty. The Hospital for Special Surgery knee score improved from a mean of 33 to a mean of 78 points in patients who had total knee replacement after total hip arthroplasty. The Hospital for Special Surgery knee score improved from a mean of 35 to a mean of 44 points in patients having total knee replacement alone below a hip arthrodesis. The followup after total knee replacement averaged 53 months. These data suggest that a knee replacement alone in a patient with a fused hip is unlikely to provide a satisfactory result. Patients with severe knee disease below hip arthrodesis require total hip arthroplasty followed by knee replacement. This applies even when severe osteoarthritis of the knee is the primary complaint.

Metacarpophalangeal joint arthroplasty in rheumatoid arthritis: results of Swanson implants and digital joint operative arthroplasty.

We discuss 69 metacarpophalangeal (MP) implant arthroplasties performed in 30 patients with rheumatoid arthritis. The follow-up averaged 5 years. We studied 19 finger joint prostheses by Condamine, digital joint operative arthroplasty (stabilized version; DJOA) and 50 flexible silicone Swanson implants. We used a new comprehensive scoring system to evaluate the MP alloarthroplasties. Such a scoring system incorporates clinical and radiological data. The outcome following MP joint replacement with DJOA was never evaluated as 'good'; in 11 joints the result was 'fair', and in 8 joints, 'poor'. As regards MP arthroplasty with Swanson implants, the results were evaluated as 'good' in 40 joints, as 'fair' in 10 joints, and in none as 'poor'. In our series, DJOA did not provide stability in arthritic MP joints. In all joints replaced with DJOA, dislocation of the articulating surfaces and signs of loosening were present. We regard three factors as being the main causes contributing to the poor outcome of DJOA when used as MP replacements. Firstly, the proximal prosthetic component is poorly matched to the anatomical shape of the metacarpal bone (conisation of the bone). Secondly, adequate coaptation cannot be achieved with this prosthetic design, even in the presence of extensive soft-tissue reconstruction. Thirdly, the use of polyethylene in MP joint replacements is questionable. In contrast, the silicone Swanson implants in our series provided superior results when used as MP implants in the rheumatoid hand.

[Validation of computerized tomography antetorsion angle measurement of the femur]. / Validierung computertomographisch gemessener Antetorisonswinkel am Femur.

AIM OF THE STUDY: Several CT-procedures exist to determine rotational variances of the femur. However, solely on the basis of few CT-scans and without a three-dimensional reconstruction of the femur, it is impossible to define the exact course of the femoral neck axis. Looking for determination of the exact course of the femoral neck axis, auxiliary constructions need to be called upon. Aim of the study was to validate several existing CT-procedures and analyse their respective error rates. METHOD: Fourty-five femora were CT-scanned and subsequently reconstructed three-dimensionally in this study. Femoral anteversion was measured using three different CT-methods in each of these femora and in addition, the respective anatomical anteversion was determined in each femur. In order to test the reliability of such methods, flexion of the femora around the center of the femoral head as well as a varus deformity of the longitudinal axis of the femora were simulated and anteversion measurements were repeated in such simulated positions. Results were statistically analysed using SPSS. RESULT: All tested CT-methods, when compared to the anatomical anteversion of a femur, showed differing anteversion-angles with statistical significance (p < 0.001). Equally, the results of the individual methods tested differed with significance. Due to a high correlation with the anatomical anteversion, all methods examined expressed trend of anteversion. Under simulated hip flexion, the "Ulmer Method" produced different values with statistical significance which were, however, without correlation to anteversion values in joint extension. With statistical significance, the "Essener Method" produced different anteversion values when the longitudinal axis of the femur was modified; however, these values highly correlated to anteversion values of femora with unchanged longitudinal axis. CONCLUSION: Our results lead us to conclude that the "Essener Method" being an interindividual method and independent from positioning, is the most suitable procedure as it allows for the correction of errors with respect to anatomical anteversion.

[Artificial hip joint implantation in stiff-man syndrome]. / Künstlicher Hüftgelenksersatz bei Stiff-Man Syndrom.

UNLABELLED: AIM AND METHOD OF THE STUDY: The Stiff-Man syndrome is characterized by progressive, usually symmetric rigidity of the axial muscles of the trunk with superimposed painful spasms precipitated by various stimuli. The neurologic disorder of SMS is discussed with respect to its symptoms of orthopedic interest including treatment modalities for total hip replacement. RESULTS: An increased incidence of hip disease in patients with SMS seems unlikely according to our analysis. CONCLUSION: SMS-patients should, however, be defined at risk for heterotopic bone formation following hip arthroplasty requiring a perioperative prophylaxis.

[Acetabular reconstruction using acetabular reinforcement rings]. / Pfannenrekonstruktion mit Pfannenstützschalen.

Reviewing the literature the revision arthroplasty of the hip joint with acetabular reinforcement rings shows good results concerning a follow-up period of six years in comparison with cemented or non-cemented primary implants. We use different acetabular reinforcement rings with differentiated indications. The primary assignment is the secure fixation of the ring to the vital bone. The acetabular bone defect is filled with autogenous or homogeneous bone grafts. The increasing number of massive acetabular defects made us develop a new acetabular reinforcement ring. It allows a better fixation than the Burch-Schneider Ring and is cheaper than the individual acetabular implant. Since 1988 we performed 262 revision arthroplasty with acetabular reinforcement rings. Until 1996 we evaluated 174 reinforcement rings (41 Müller rings, 72 Ganz rings, 41 Burch-Schneider rings, 6 RS or RSH ring, 5 individual acetabular implants). After an average follow-up period of 5.6 years a radiological or clinical loosening of the acetabular component occurred in only 6 patients (3.4%). To reach a better comparison of the surgical results we developed a score, which differentiate checks the operative goals. On plane pelvic radiographs we checked the reconstruction of the rotation center, the demarcation of the acetabular component and the outcome of the bone transplant.

[Total femur replacement following multiple periprosthetic fractures between ipsilateral hip and knee replacement in chronic rheumatoid arthritis. Case report of 2 patients]. / Totaler Femurersatz nach mehrfachen periprothetischen Frakturen zwischen ipsilateralem Hüft- und Kniegelenksersatz bei chronischer Polyarthritis. Falldarstellung von 2 Patienten.

Periprosthetic femur fractures are one of the most severe complications in hip surgery. Osteoporosis as seen in patients with rheumatoid arthritis could favour such fractures, which are located mostly between the stems of the hip and knee prostheses. A traumatic event is not even required. The fracture rate increases with predisposing factors, such as preliminary changes of the prosthesis or osteoporosis. This paper reports two patients with rheumatoid arthritis (males, 54 and 71 years old) with femur fractures after total hip and knee replacements. Both had a severe osteoporosis caused by a long-term steroid therapy. Consecutively, both patients showed refractures of the femur with loosening of the osteosynthetic material, so that a total femur replacement was required. However, both patients are able to walk. To reduce the risk of femur fractures between the tips of knee and hip prostheses it is advisable to use knee prostheses without a proximal intramedullary stem. In this way pressure stress is reduced.

[EMG-assisted functional analysis within the scope of follow-up of arthroscopically managed injuries of the anterior cruciate ligament]. / EMG-gestützte Funktionsanalyse im Rahmen einer Nachuntersuchung nach arthroskopisch versorgten vorderen Kreuzbandverletzungen.

The rehabilitative course of anterior cruciate ligament ruptures was followed up at 16.6 months postoperatively be measuring clinical parameters, isokinetic power values and by means of electromyographic leads. The injured side has significantly looser ligaments than the non-injured one (p = < 0.01). The circumferential measures differ from each other, pointing to a reduction in muscular circumference at the measuring points 10 cm and 20 cm above the medial joint cavity (p = < 0.05). The isokinetic measurements had selective deficits of the knee-joint extensor at 60 degrees W/S (p = < 0.01) and at 180 degrees W/S (p = < 0.05), whereas the flexors did not show any difference, irrespective of the side. EMG measurements after 16.6 months via superficial leads applied to the synergistic compound of the extensors of the knee joint did not confirm any weakness of the m. vastus medialis although such weakness has often been claimed to exist. Laterally changed electromechanical coupling was seen, as well as a changed muscular fatigue pattern. The changed synergistic functional capacity of the m. quadriceps femoris could be of pathogenetic importance for further, e.g. retropatellar, subsequent damage. The author discusses the question whether laterally equal muscular conditions based on traumatically changed conditions in the joints should be treated at all.