Decreased lubricin concentrations and markers of joint inflammation in the synovial fluid of patients with anterior cruciate ligament injury.

OBJECTIVE: To study the effect of anterior cruciate ligament (ACL) injury on lubricin concentrations in synovial fluid (SF) and its correlation with time postinjury, inflammatory cytokines, lubricin-degrading enzymes, and SF proteoglycan content. METHODS: SF samples were obtained from both knees of 30 patients with unilateral ACL insufficiency, 32-364 days postinjury. Lubricin, inflammatory cytokines (interleukin-1beta [IL-1beta], tumor necrosis factor alpha [TNFalpha], and IL-6), and catabolic enzymes (procathepsin B and neutrophil elastase) were measured in SF from injured and contralateral (uninjured) joints, by enzyme-linked immunosorbent assay. Sulfated glycosaminoglycan (sGAG) levels in the SF were measured by Alcian blue binding assay. RESULTS: SF lubricin concentrations were significantly (P < 0.001) reduced at an early stage following ACL injury when compared with those in the contralateral joint. Within 12 months, the lubricin concentration in the injured knee (slope = 0.006, SE = 0.00010, P < 0.001) approached that in the contralateral knee, which did not change with time (slope = -0.0002, SE = 0.00050, P = 0.71). TNFalpha levels showed a significant negative relationship with log2 lubricin levels. IL-1beta, TNFalpha, IL-6, procathepsin B, and neutrophil elastase concentrations in SF from injured knees were greater in samples from recently injured knees compared with those that were chronically injured. There were no detectable cytokines or enzymes in the SF of contralateral joints. Concentrations of sGAG were significantly (P = 0.0002) higher in the SF from injured knees compared with the contralateral joints. CONCLUSION: The decrease in SF lubricin concentrations following ACL injury may place the joint at an increased risk of wear-induced damage as a consequence of lack of boundary lubrication, potentially leading to secondary osteoarthritis. The decrease in SF lubricin was associated with an increase in levels of inflammatory cytokines.

The accuracy of the clinical knee examination documented by arthroscopy. A prospective study.

The diagnostic accuracy of the clinical examination for intraarticular injuries of the knee was documented by arthroscopy over a 6-month period. Two-hundred ninety patients (296 knees) were evaluated by history, physical examination, and standard radiographs. Supplemental diagnostic studies included 41 magnetic resonance images, 2 arthrograms, and 1 previous arthroscopy that had been recently performed. Overall, the correct diagnosis was made in 165 knees (56%), an incomplete diagnosis in 92 (31%), and an incorrect diagnosis in 39 (13%). There were only 2 knees (0.07%) with no discernable lesions. When a single lesion was present in the knee, the diagnosis was made correctly in 72% of cases. When more than 2 were discovered, the diagnosis was correct in only 30%. However, all individual lesions were diagnosed with an accuracy of greater than 90%. The lesions most difficult to diagnose were chondral fractures, fibrotic fat pads, tears in the anterior cruciate ligament, and loose bodies. Knees with acute lesions and those with a single diagnosis proved to be significantly easier to diagnose (P < 0.01). The variables that proved to be insignificant were age, sex, magnetic resonance imaging, surgeon, workers' compensation, or pending litigation.

Responses of rat pleural mesothelia to increased intrathoracic pressure.

Direct measurements of pleural fluid hydrostatic and colloid osmotic pressures after infusion of saline, bovine serum albumin, or silicone into the pleural space were coupled with ultrastructural morphometric analyses to assess the response of pleural mesothelial cells to hydrothorax. Increases of hydrostatic pressure, either independent or in combination with decreases of osmotic pressure, served to increase the number of plasmalemmal vesicles in mesothelial cells of both the visceral and parietal pleurae. These results support the hypothesis that an increase in vesicle numerical density represents a response to elevations of extracellular fluid pressures. Fluid resorption from the pleural space with subsequent accumulation within the visceral pleural interstitium was also associated with the formation of invaginations of the mesothelial basal plasmalemma. That the invaginations were not observed in the absence of interstitial fluid accumulation supports the concept that basal surface invaginations represent distortions of mesothelial cell membranes in response to pressure differentials across the plasmalemma. The results of this study are most consistent with the interpretation that increased numbers of plasmalemmal vesicles and invaginations of the basal plasmalemma represent adaptive conformational mechanisms of pleural mesothelial cells to prevent monolayer disruption by elevated extracellular fluid pressures.

The prone position for elbow arthroscopy.

Using the prone position for diagnostic and therapeutic arthroscopy improves intraoperative stability of the arm and allows the surgeon to approach the joint in a more intuitive manner. With this position, indications for elbow arthroscopy are increased and risks to neurovascular structures are reduced. Access to the posterior chamber is facilitated when the patient is in a prone position. This article describes both this arthroscopic technique and portal anatomy.

Two-stage correction of thumb adduction contracture in Freeman-Sheldon syndrome (craniocarpotarsal dysplasia).

Freeman-Sheldon syndrome is a rare congenital anomaly that is characterized by facial, hand, and foot deformities. We describe a female infant who had severe adduction contractures of the thumbs. A two-stage reconstruction was done. The first web space soft tissues were stretched with a transversely oriented external skeletal distractor, then a conventional first web space deepening and release was performed.