Pigmented villonodular synovitis: keys to early diagnosis.

Pigmented villonodular synovitis is a synovial proliferative disorder that remains a diagnostic difficulty. Many clues in the history, physical examination, and radiographic studies can aid in the diagnosis. A patient in the third or fourth decade of life often will present with vague monoarticular complaints. Symptoms include intermittent, extreme deep pain localized to the hip, occasionally relieved by position. Decreased active and passive range of motion may be found. Small erosions in the head of the femur and acetabulum may occur early in the course of the disease. Magnetic resonance imaging is the imaging modality of choice and will show the characteristic findings of a joint effusion, synovial proliferation, and bulging of the hip. The synovial lining has a low signal on T1- and T2-weighted images, secondary to hemosiderin deposition. Pigmented villonodular synovitis should be included in the differential diagnosis of young patients with unexplained hip pain.

Early failure associated with the use of Hylamer-M spacers in three primary AMK total knee arthroplasties.

We report 3 cases of early failure associated with AMK total knee arthroplasties with the use of Hylamer-M spacers. In 2 of these cases, massive osteolysis of the posterior condyles was noted; revision with the use of allograft bone to fill in the cavitary defects yielded excellent results. In all cases, large areas of pitting and delamination of the Hylamer spacers were noted. Given these cases and the previous literature on early failure of hip arthroplasties with Hylamer inserts, we recommend caution in using Hylamer for knee arthroplasty surgery.

Surgical treatment options for cartilage defects within the knee.

Injury to articular cartilage is increasingly diagnosed as a cause of knee pain. New surgical treatment options are now available to treat this clinical entity. Diagnosis is made easier by improved magnetic resonance imaging protocols that better visualize articular cartilage. On physical examination, patients at any age can have joint surface damage and primarily experience joint line tenderness and pain with activity. Treatment options include debridement of nonviable cartilage with abrasion or microfracture of the subchondral bone, transplantation of autologous osteochondral plugs, autologous chondrocyte transplantation, transplantation of cadaveric allogenic osteochondral grafts, and, for irreparable damage, total knee arthroplasty. These newer treatment options show promising early and intermediate results.

Observer variation in the detection of acetabular bone deficiencies.

To determine observer variation in the detection of acetabular bone deficiencies, 42 pairs of frontal (AP) and lateral hip radiographs and CT studies for total hip arthroplasty patients obtained within an average of 4 weeks of each other were reviewed separately by five radiologists and one orthopedic surgeon. Interobserver variations were calculated for each individual reading the films using kappa values. The individual film readings were then compared with a consensus reading of the CT data. When separate observers were analyzed, agreement on plain film readings was slight to fair (av. kappa = 0.1440 +/- 0.1047). The individual observers were not able to give readings which were very consistent with the CT consensus reading, resulting in a low sensitivity (65%) and specificity (74%) for acetabular defect classification with plain radiographs. The identification of acetabular bone defects from the AP and lateral views of the hip is highly subjective and variable from observer to observer.