Etiological aspects in osteochondritis dissecans patellae.

In a retrospective study probable etiological factors of rare cases of osteochondritis dissecans of the patella were analyzed. Anamnestic data and data obtained from standardized roentgenography in the anterior-posterior, axial, and lateral views of the patella were evaluated. Anamnestic data provided no evidence of the etiology in addition to the fact that several patients mentioned a single or multiple trauma. In contrast to this, evaluation of the roentgenograms showed that most of the patients with osteochondritis patellae exhibited a flat articular surface of the patella (types I and V in Hertel's classification) and a distinct accumulation of the patellae with greater lateral than medial facet (types II and III in Wiberg's classification). Furthermore, the axial shape of the patellar groove exhibited a distinct accumulation of type III trochleae, representing a hypoplasia of the medial and hyperplasia of the lateral part of the trochlea. Evaluation of the lateromedial patellar alignment revealed in a distinct accumulation of grade II dislocation medially and laterally. Although the data were obtained from a rather small number of patients, in our opinion these results support the theory of biomechanical induction of osteochondritis dissecans patellae. Further dynamic analyses are needed to clarify biodynamic effects on the patella and the patellofemoral joint.

Cost analysis of three different surgical procedures for treatment of a pelvic tumour.

INTRODUCTION: Malignant pelvic tumours are rare, but adequate treatment is difficult because of anatomical and functional reasons. Different surgical procedures are recommended. Besides aspects influencing the quality of life due to the different surgical techniques, costs of these surgical procedures and the perioperative time interval, depending on the chosen surgical procedure, must also be considered. METHODS: Costs of three kinds of surgical treatment - internal hemipelvectomy vs external hemipelvectomy and application of an orthotic device vs ilio-femoral pseudoarthrosis - were compared, including costs of the immediate period of rehabilitation. Costs of the preoperative diagnostic procedure were excluded because they were assumed to be equal. For all calculations, treatment of a periacetabular pelvic tumour type II-b was assumed, according to the Enneking classification, with the need for a pelvic resection with wide margins including removal of the hipjoint. This analysis was performed based on the average costs per hour of physicians, nurses and physiotherapists, including a basic daily rate for additional costs, such as housekeeping and administrative costs of the hospital. In all cases, the costs of the operative procedure and the perioperative period up to 3 months were calculated, including the costs for the endoprosthetic device after internal hemipelvectomy and those for the orthotic devices after necessary external hemipelvectomy. RESULTS: For a postoperative period of 3 months, the cost for treatment with resection of the tumour and performing an ilio-femoral pseudoarthrosis is nearly DM 56,741.54; treatment with an internal hemipelvectomy including the endoprosthetic pelvic replacement costs DM 81,439.34; and treatment with external hemipelvectomy and application of an orthotic device with a pelvic cage costs DM 69,138.46. In this analysis, social costs due to the different rates of disability for years or costs of a new prosthetic device after years and aspects related to resulting quality of life were excluded. In contrast, costs of three different actual cases can differ significantly from the estimated costs. The most important influencing items are surgical implants, blood units and similar products, and surgical treatment of postoperative complications. CONCLUSIONS: Regarding all these aspects, limb salvage seems to be advantageous over amputation. Whether an ileo-femoral pseudoarthrosis or endoprosthetic pelvic replacement should be performed is a decision that should be made by the physicians. based on the underlying diagnosis and the correlated expected survival. Furthermore, additional factors probably reducing the rate of postoperative complications, such as infections or necrosis following radiotherapy and being summarised under the term "quality of life", should also be regarded.

Haematogenous tuberculous infection following revision of a loosened total hip replacement.

A case of tuberculous arthritis complicating revision of a total hip replacement (THR) is reported. Primary THR was performed for arthrosis of the hip and the patient underwent revision because of aseptic loosening. After this surgical procedure, secondary infection with Mycobacterium tuberculosis occurred. Bacterial contamination due to haematogenous spread probably from a reactivated old quiescent tuberculous pleural focus is proposed as the most likely source of infection in this patient. Tuberculous infections in THR are rare but prophylactic use of antituberculous drugs in patients with a history of tuberculosis may reduce the risk of reactivation of old foci and serve to eliminate contamination of prosthetic replacements.

Internal hemipelvectomy and endoprosthetic pelvic replacement: long-term follow-up results.

We report on our experiences with internal hemipelvectomy followed by an implantation of a endoprosthetic pelvic replacement (EPR) performed in 15 patients over a period of 15 years. Our primary aim was to determine the implications for this procedure because of its high rate of complications. Due to the malignant character of the disease and the biomechanical stress on the anatomical region, the demands on the surgeon are high. The most important factor is a sufficiently wide resection of the primary tumour because most are chondrosarcomata which do not respond to other therapies. In addition, the malignant character of the tumour has the greatest influence on the long-term results. Internal hemipelvectomy and endoprosthetic pelvic replacement are accompanied by a high rate of operative and postoperative complications Nevertheless, nearly full anatomical and functional reconstruction can be obtained provided a medium level of function is accepted. Follow-up results of the remaining six still living patients were evaluated by means of three different scoring systems. All patients had only a medium score but emphasised subjective acceptance of the endoprosthetic pelvic replacement even when removal was necessary later on. Because of the lower functional outcome of alternative operative procedures such as pseudarthroses and arthrodeses and problems with the replantation of autoclaved autografts or implantation of an allograft, internal hemipelvectomy combined with endoprosthetic pelvic replacement is the treatment of choice for these specific acetabular lesions, provided a complete resection is feasible. Otherwise, an external hemipelvectomy is necessary because even alternative limb-salvaging procedures must incorporate the same complete resection of the tumour. In cases of metastatic lesions, internal hemipelvectomy and endoprosthetic pelvic replacement are indicated relatively because of the systemic character of the disease. The procedure should be considered only when resection of a solitary metastasis enables a cure and/or prolongation of life with an improved quality of life.

The stabilizing effect of orthotic devices on plantar flexion/dorsal extension and horizontal rotation of the ankle joint. An experimental cadaveric investigation.

The mechanical stabilizing effect of nine different orthotic devices on physiological and pathological plantar flexion/dorsal extension and horizontal rotation of the ankle joint subjected to artificial lateral ligament lesions was investigated in 20 cadaveric ankle joints under standardized conditions using an experimental apparatus. All of the braces tested significantly reduced plantar flexion/dorsal extension, as well as internal/external/external horizontal rotation, under the experimental conditions. In so far as these results can be transposed into a clinical setting, our data favour that bracing significantly reduces the instability. But, other criteria, such as the stabilizing effect on talar tilt and anterior drawer sign, the price and the convenience of wearing such devices have to be taken into consideration when choosing the optimal brace.

Pressure distribution in the knee joint. Influence of flexion with and without ligament dissection.

Biomechanical factors influencing the patterns of pressure distribution at the articular surface and the subchondral bone are suggested to be most important in the pathogenesis of osteoarthritis and osteochondritis dissecans at the knee joint. Besides this, chronic joint instability is another important factor under discussion in the etiology of osteoarthritis of the knee. The patterns of pressure distribution on the femoral condyles of weight-bearing knee joints were investigated in a biostatic cadaver model. The pressure on the femoral condyles was evaluated using pressure-sensitive films with the knee in different physiological joint positions (extension, 15 degrees and 30 degrees flexion) with and without division of either the medial collateral ligament (MCL), the lateral collateral ligament (LCL), the MCL and the anterior cruciate ligament (ACL), or the LCL and the ACL. Results showed that the location of the contact area and peak pressure depended on the joint position and stage of ligament division. Without ligament division the maximum peak pressure was always observed on the medial condyle. Only after MCL and combined MCL + ACL division did the lateral condyle show in extension a higher peak pressure than the medial condyle. Division of the LCL and LCL + ACL resulted in an increase in peak pressure on the medial condyle, particularly in flexion. The highest peak pressure of all was measured in the 30 degrees flexion position on the medial condyle after division of the LCL. The lowest at all was found on the lateral condyle in 15 degrees flexion after LCL division. Additional ACL division resulted in only minor further changes.(ABSTRACT TRUNCATED AT 250 WORDS)

Bilateral osteochondritis dissecans of the medial trochlea femoris: an unusual case of patellofemoral pain.

We report a case of bilateral osteochondritis dissecans of the medial trochlea femoris. Arthroscopic removement of loose bodies in the symptomatic left knee led to an excellent result; the untreated right knee showed effusion and locking one year later. This condition should be considered in the diagnosis of patellofemoral pain.

Pressure distribution at the knee joint. Influence of varus and valgus deviation without and with ligament dissection.

Traumata or repetitive microtraumata, malalignment with varus or valgus deviation, or chronic joint instability are discussed in the aetiology of osteoarthritis and osteochondritis dissecans of the knee. Biomechanical factors influencing the patterns of pressure distribution at the articular surface and the subchondral bone are suggested to be most important in the pathogenesis. Consequently, the patterns of pressure distribution at the femoral condyles of weight-bearing knee joints were investigated in a cadaveric biostatic model. The pressure in the articular joint space was evaluated with pressure-sensitive films of the knee in different joint positions in the coronal plane (10 degrees varus, 10 degrees valgus, and neutral position) without and with medial collateral ligament (MCL), lateral CL (LCL), MCL + anterior cruciate ligament (ACL) or LCL + ACL ligament division. Results demonstrated that the location of the contact area and the peak pressure depended on the joint position and stage of ligamentous division. Without ligament division, a maximum peak pressure was observed at the medial condyle in the neutral and varus positions. Only in the valgus position did the lateral condyle show a higher peak of pressure than the medial condyle. Ligament division of the LCL and LCL + ACL resulted in an increase of peak pressure at the medial condyle, particularly in the varus position. Division of the MCL and MCL + ACL ligament complex reduced the differences between the medial and lateral condyle. In the valgus position, the peak pressure was significantly higher at the lateral condyle. The absolute maximum peak pressure was measured in the varus position at the medial condyle after division of the LCL and ACL.(ABSTRACT TRUNCATED AT 250 WORDS)