The chondrocyte primary cilium.

UNLABELLED: The presence and role of primary, or non-motile, cilia on chondrocytes has confused cartilage researchers for decades. Initial explanations attributed a vestigial nature to chondrocyte cilia. Evidence is now emerging that supports the role of the chondrocyte primary cilium as a sensory organelle, in particular, in mechanotransduction and as a compartment for signaling pathways. Early electron microscopy images depicted bent cilia aligned with the extracellular matrix (ECM) in a manner that suggested a response to mechanical forces. Molecules known to be mechanotransducers in other cell types, including integrins and proteoglycans, are present on chondrocyte cilia. Further, chondrocytes which lack cilia fail to respond to mechanical forces in the same manner that chondrocytes with intact cilia respond. From a clinical perspective, chondrocytes from osteoarthritic (OA) cartilage have cilia with different characteristics than cilia found on chondrocytes from healthy cartilage. OBJECTIVE: This review examines the evidence supporting the function of chondrocyte cilia and briefly speculates on the involvement of intraflagellar transport (IFT) in the signaling pathway of mechanotransduction through the cilium. CONCLUSIONS: Emerging evidence suggests cilia may be a promising target for preventing and treating OA.

Radiologic case study. Pigmented villonodular synovitis.

Pigmented villonodular synovitis is a benign, locally aggressive disorder characterized by a unique clinical radiographic, and histopathologic presentation. While it is considered to be a rare disorder, a delay in diagnosis and treatment can potentially result in severe disruption of joint function due to subchondral invasion. Once the diagnosis is confirmed, treatment should consist of complete synovectomy. Recurrence is common, but malignant transformation is rare. The etiology of PVNS is still unknown, and perhaps its future discovery will assist in the definitive treatment of this disorder.

The clinical utility of duplicate readings for musculoskeletal radiographs.

It is a common practice in many hospitals to have all skeletal radiographs read by a second physician, usually a radiologist, as well as by the treating physician. A two-part study was performed in order to examine the cost and clinical benefit of this practice for plain films ordered by orthopedists. In the first part of this study, the attending orthopedic surgeons were surveyed about the clinical usefulness and effect on patient care of 1000 radiologic reports from plain films ordered on orthopedic patients. In the second part, the charts of 272 patients who had 704 radiographs were reviewed with the goal of identifying any discrepancies between the orthopedic interpretation and the radiologic reading. Thirty-eight reports were discarded because they were not reports of plain skeletal films. One hundred twenty-nine of the remaining 962 radiologic reports were never read by the attending orthopedist. The average time between the taking of the film and an orthopedic attending reading the printed report was 6.1 days. Three radiology reports contained findings that were incorrect. Only one report contained findings that the orthopedist was unaware, and one report may have led to an alteration in treatment. No reports resulted in an unplanned trip to the operating room or a patient being called back to the clinic. Of the 272 chart reviews (704 reports), 70 had no orthopedic interpretation recorded and 94 had no radiologic report in the chart. Twelve discrepancies were noted in the cases that had both reports. Four fracture displacements were identified by orthopedists, but not on the written radiology report; three of these required a return to the operating room. Four instances of hardware displacement or breakage were noted by orthopedists, but not commented on by the radiologists. Three incidental injuries (two fractures and an acromioclavicular injury) were noted on printed reports of films taken for other reasons, but not commented on by the orthopedist, and not treated. A dorsal bunion was noted on one film by the orthopedist, but not by the radiologist. From this study, one can conclude that the benefit of routine duplicate radiograph interpretation by a second physician does not justify its cost.