Pyomyositis of the anterior tibial compartment.

Five oncology patients developed bacterial pyomyositis involving the anterior tibial compartment and resulting in compartment syndrome with ischemia and abnormalities of neuromuscular function. All patients were neutropenic and thrombocytopenic, and four were receiving or had recently received cancer chemotherapy. Three infections were due to gram-negative bacilli and two to Staphylococcus aureus. Appropriate antimicrobial therapy and surgical drainage in four patients resulted in the resolution of these infections with good residual muscle function. To our knowledge, primary pyomyositis has never previously been known to cause compartment syndrome.

Surface replacement of the hip with the Tharies system. Two to five-year results.

The two to five-year clinical results of 200 Tharies surface replacements were comparable to those of conventional total hip replacement. The incidence of systemic complications, dislocations, and sepsis was low. There were ten cases of aseptic and one case of septic loosening. Nine minor secondary procedures were required in the series. In two patients the femoral component shifted asymptomatically into varus angulation, but no revision was needed. Fifty-five per cent of patients for whom serial radiographs were available had some progression of radiolucency, but there was poor correlation between the width of the zone and loosening until the patient became symptomatic. Improved techniques of preparation of the interface and of delivery, compression, and containment of the cement have improved the postoperative radiographic appearance of the more recently treated patients.

THARIES surface replacements: a review of the first 100 cases.

The first 100 cases of the 135 THARIES surface replacement procedures with 4--32 months follow-up, are evaluated in terms of clinical results, radiographic information and complications. The short but detailed follow-up suggests that this procedure was an excellent alternative for the younger and more active population. The overall hip ratings (pain, walking and function) and range of motion are comparable to that of stem-type total hip replacements. When the THARIES and conventional hip results are further compared in 34 patients matched by sex and age for 3 major etiological groups (osteoarthritis, osteonecrosis and congenital hip dysplasia), the interim results are essentially comparable for both types. Three cases in the first 100 have required revision. One patient (no. 1) with osteoporosis, chondrolysis and arthrofibrosis following slipped capital femoral epiphysis had loose femoral and acetabular components 24 months postoperatively. He was revised to a T-28 hip replacement. The polyethylene socket in another patient (no. 4), the first dysplastic hip in this series, was 20 nm uncovered superiorly, became loose and was revised 9 months postoperatively. Now 15 months postoperative with a more medial THARIES acetabulum, the patient continues to have a good result. Another patient (no. 12) with bilateral dysplastic hips became progressively more disabled due to heterotopic bone, which was then excised 18 months postoperatively. Radiographic studies of the THARIES sockets demonstrate radiolucent zones at the cement-bone interfaces of the acetabulum in 88 cases, partial in 51 and complete in 37. Three hips were currently considered to have evidence of progressive socket loosening but are active and asymptomatic. There have been no femoral neck fractures in this series which we attribute to the custom fitting ability inherent in the range of components, the reaming protocol and the various remodelling guides. There have been no prosthetic breakages, subluxations, dislocations or sepsis. The complications observed in this series are minor and comparable to that of many other total hip arthroplasty operations. Nerve palsy and trochanteric separation have not been major problems although one existing peroneal nerve dysfunction and one trochanteric migration emphasize the need to minimize these complications by careful handling of the operative leg, and an accurate trochanteric reattachment technique.

In vivo knee stability. A quantitative assessment using an instrumented clinical testing apparatus.

Twenty-eight male and twenty-one female subjects with no history of previous injury to their knees were examined using a newly developed clinical testing apparatus designed to record anterior-posterior tibial force versus displacement and varus-valgus moment versus angulation during manual manipulation of the knee. Joint stiffness and laxity were measured from test tracings made with the knee muscles relaxed and tensed. Agreement between these measurements and those made previously on thirty-five fresh cadaver knee specimens was very good. Anterior-posterior laxity averaged 3.7 millimeters in full extension, 5.5 in 20 degrees of flexion, and 4.8 millimeters in 90 degrees of flexion, while the mean varus-valgus laxity was 6.7 degrees in full extension. The common clinical assumption that normal right-left differences are negligible was found to be invalid. Individual right-left differences averaged 26 to 35 per cent for laxity and 19 to 24 per cent for stiffness. There was no discernible tendency for one knee to be more stable than the other; random interchanges of relative stability between the right and left knees were observed for each individual at different knee positions. When requested to tense the knee muscles, these subjects were able to increase their knee stiffness an average of two to four times while knee laxity was reduced to 25 to 50 per cent of the normal value.