Congruence and joint space width alterations of the medial compartment following lateral unicompartmental knee arthroplasty.

Progressive degenerative changes in the medial compartment of the knee following lateral unicompartmental arthroplasty (UKA) remains a leading indication for revision surgery. The purpose of this study is to evaluate changes in the congruence and joint space width (JSW) of the medial compartment following lateral UKA. The congruence of the medial compartment of 53 knees (24 men, 23 women, mean age 13.1 years; sd 62.1) following lateral UKA was evaluated pre-operatively and six weeks post-operatively, and compared with 41 normal knees (26 men, 15 women, mean age 33.7 years; sd 6.4), using an Interactive closest point algorithm which calculated the congruence index (CI) by performing a rigid transformation that best aligns the digitised tibial and femoral surfaces. Inner, middle and outer JSWs were measured by sub-dividing the medial compartment into four quarters on pre- and post-operative, weight bearing tunnel view radiographs. The mean CI of knees following lateral UKA significantly improved from 0.92 (sd 0.06) pre-operatively to 0.96 (sd 0.02) (p < 0.001) six weeks post-operatively. The mean CI of the healthy control group was 0.99 sd 0.01. Post-operatively, the mean inner JSW increased (p = 0.006) and the outer decreased (p = 0.002). The JSW was restored post-operatively as no significant differences were noted in all three locations compared with the control group (inner JSW p = 0.43; middle JSW p = 0.019, outer JSW p = 0.51). Our data suggest that a well conducted lateral UKA may improve the congruence and normalise the JSW of the medial compartment, potentially preventing progression of degenerative change.

Concealed knee cartilage lesions: is arthroscopic probing therapeutic?

We report on 34 knee arthroscopic procedures (of 976 knee procedures performed during a 2-year period) performed on patients with chronic knee symptoms or symptoms mimicking a torn meniscus. All patients had deep articular cartilage lesions over which the superficial cartilage appeared normal. These lesions were not diagnosed on radiographs, magnetic resonance imaging, or bone scintigraphy. Only careful arthroscopic probing disclosed the deep cartilage separation. The treatment consisted of cartilage puncturing with a probe, which in 14 cases led to the evacuation of blood. This simple technique produced resolution of symptoms in 30 (88.2%) patients. This condition affects athletes and soldiers undergoing military training and, in many cases, is an expression of an overuse syndrome. The incidence of these lesions was 3.5% in a series of relatively young patients. The lesion should be suspected in cases of unexplained knee pain in the athlete and soldier and in patients with previous negative arthroscopic examinations or meniscal lesions that were treated but remained unresolved. To our knowledge, bleeding from "closed" cartilage lesions has not been previously described. We raise the question of whether arthroscopic probing and cartilage puncturing is the method of treatment.

Orthopedic disability, conformity, and social support.

The relation between physical disability, social support, and conformist behavior was tested in two studies. The first compared the conforming responses of persons who had orthopedic disabilities with those of able-bodied individuals and correlated perceived social support of those with the disability with their tendency to conform. The second was an experimental study in which university students made choices between actors who had disabilities and actors who were able bodied; orthopedic disability was signified by a person sitting in a wheelchair and social support by the choice of a teammate. Results showed that persons with disabilities (compared with those who were able bodied) reported a significantly higher tendency to conform and that this tendency was negatively related to reported levels of perceived social support. In the experimental study, conforming behaviors of both disabled and able-bodied actors elicited more social support than did assertive behaviors. The actors who had "disabilities" received less social support than those who were "able bodied," but the former were considered more original when they did not conform. The findings imply that individuals with orthopedic disabilities are expected to conform but, although their conforming behavior elicits social support within specific encounters, it does not affect overall social support across encounters.

Arthroscopic treatment of sports-related synovitis of the ankle.

We describe nine cases of sports-related synovitis of the ankle joint with a followup of 24 to 44 months (average, 30.9). It affects young athletes and occurs after episodes of acute or recurrent inversion ankle sprains or undisplaced ankle fractures. The patients complain of morning pain and stiffness along with increased pain and swelling with attempted athletic participation. All ankles were stable and all failed to respond to at least 6 months of conservative treatment. The technetium bone scans were positive in eight of the cases. During arthroscopy, a hypertrophic anterior-chamber synovitis was found and treated by arthroscopic partial synovectomy. The results were excellent in eight of the patients in whom symptoms resolved, allowing full return to their previous sports, and fair in one case. The only complication was one superficial wound infection.

Sensitivity of cultured human osteosarcoma and chondrosarcoma cells to retinoic acid.

The ability of retinoic acid (RA) to inhibit the growth of three cell lines (Te85, Hs781, and Hs791) derived from human osteosarcomas and two cell lines (Hs705 and Hs819) derived from human chondrosarcomas was studied in culture. The exposure to 10(-5) M RA resulted, within 4 days, in changes in both cell morphology and cell growth. RA-treated cells appeared flat and spread on the substratum more than untreated cells, their exponential growth rates decreased, and their saturation densities were markedly reduced. All these effects could be reversed by removal of RA from the growth medium. The various cell lines exhibited differential susceptibility to the growth-inhibitory effect of RA. The most sensitive was the Hs705 chondrosarcoma. The proliferation of these cells was inhibited 50% by 10(-9) M RA and was completely blocked by 10(-5) m RA. In contrast, the concentrations of RA required for 50% inhibition of Hs791, Te85, Hs819, and Hs781 were 10(-7), 2 X 10(-7), 2.5 X 10(-7), and 2 X 10(-6) M, respectively. Only the Te85 and the Hs781 osteosarcoma cells and cells derived from a chondrosarcoma biopsy were able to form colonies in a semisolid medium, and this growth was dramatically inhibited by RA. These results demonstrate that RA can suppress in these mesenchymal tumor cells the expression of morphological and growth properties frequently associated with transformed cells.