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The recent increase in the popularity of minimally invasive surgery has dramatically altered the technique that most surgeons use to perform unicondylar knee arthroplasty. This change in technique brings new difficulties to both the surgeon and the patient, such as the potential for new complications related to the limited surgical exposure and the need for surgeons to learn the new operative procedures. In this report, we describe the cases of four patients who required arthroscopic removal of a loose cement fragment after a minimally invasive unicondylar knee arthroplasty. We believe that this complication was related to the decreased visualization in the posterior compartment of the knee associated with the use of small incisions and cementing of the all-polyethylene tibial component. Our patients were informed that data concerning the cases would be submitted for publication. Case 1. A seventy-year-old man with a history of a left unicondylar knee replacement presented with increasing pain in the right knee. The findings on physical examination and radiographs were consistent with severe osteoarthritis of the medial compartment of the knee. In April 2003, the patient underwent a right unicondylar knee replacement through a minimally invasive incision. Both the femoral and the tibial components (Preservation; DePuy, Warsaw, Indiana) were cemented (Fig. 1). The thickness of the all-polyethylene tibial component was 9.5 mm. Fig. 1 Postoperative lateral radiograph showing the posterior cement mantle (arrowhead) fixed to the prosthesis. In June 2003, the patient presented with acute pain after feeling a “popping” in the right knee. Physical examination revealed a mild effusion and some ecchymosis about the posterior aspect of the knee. Radiographs revealed a fragment of cement that appeared to be lying free within the joint space (Fig. 2). Previous radiographs from the six-week postoperative examination showed that the cement fragment had been fixed to the posterior aspect …

Background Computer-based diagnostic systems are available commercially, but there has been limited evaluation of their performance. We assessed the diagnostic capabilities of four internal medicine diagnostic systems: Dxplain, Iliad, Meditel, and QMR. Methods Ten expert clinicians created a set of 105 diagnostically challenging clinical case summaries involving actual patients. Clinical data were entered into each program with the vocabulary provided by the program's developer. Each of the systems produced a ranked list of possible diagnoses for each patient, as did the group of experts. We calculated scores on several performance measures for each computer program. Results No single computer program scored better than the others on all performance measures. Among all cases and all programs, the proportion of correct diagnoses ranged from 0.52 to 0.71, and the mean proportion of relevant diagnoses ranged from 0.19 to 0.37. On average, less than half the diagnoses on the experts' original list of reasonab...

Excerpt The goal of the American Board of Internal Medicine is to improve the quality of medical care in the United States. It does this by developing standards to ensure that the certified interni...