Extensor triggering in de Quervain's stenosing tenosynovitis.

Extensor triggering is an uncommon but recognized component of de Quervain's stenosing tenosynovitis. In a retrospective review of 827 patients with the diagnosis of de Quervain's disease over a 5-year period, 11 patients with 13 affected wrists were identified who had demonstrable triggering by both history and physical examination (prevalence of 1.3%). One wrist underwent surgical release without conservative treatment. The remaining 12 wrists were initially treated with nonoperative modalities. Failure of conservative treatment as defined by recurrent triggering and pain occurred in 7 wrists, of which 5 underwent surgical release. At the time of surgery, all wrists were noted to have synovitis, separate compartments for the extensor pollicis brevis and abductor pollicis longus tendons, and no intratendinous nodules. After an average follow-up period of 42 months (range, 5.7-94.5 months) there were no recurrences of triggering after surgical treatment. Seven of 12 wrists with triggering de Quervain's stenosing tenosynovitis failed nonoperative treatment. Triggering or locking in extension is an uncommon symptom in de Quervain's stenosing tenosynovitis and demonstrates a more recalcitrant course when treated nonoperatively.

Effect of link protein and free hyaluronic acid binding region on spacing of proteoglycans in aggregates.

Aging of articular cartilage results in accumulation of aggrecan fragments of various sizes that retain their ability to aggregate even though they may have relatively few glycosaminoglycan chains. Residual binding of partially degraded aggrecan may prevent binding of newly synthesized aggrecan subunits that have greater numbers of glycosaminoglycan chains. This study was undertaken to determine the effects of various relative molar ratios of intact aggrecan, link proteins, and hyaluronic acid binding region fragments on the structure of reconstituted aggregates. High molar ratios of link proteins relative to aggrecan decreased the spacing between adjacent aggrecan subunits; low molar ratios of hyaluronic acid binding region relative to aggrecan (4:1 or less) had no significant effect on spacing, and high molar ratios resulted in an increase in the spacing and a decrease in the percentage of aggrecan subunits found in aggregates. These data suggest that the density of aggrecan subunits on the aggregate is determined primarily by steric hindrance of the glycosaminoglycan chains of the aggrecan subunits and that, to a limited extent, partial degradation of aggrecan in an aggregate allows attachment of more aggrecan subunits.