Steven P. Sampson

Pathobiology of the human A1 pulley in trigger finger

Eighty-nine A1 pulleys from 65 patients with trigger digits and 20 control A1 pulleys from fresh-frozen cadavers were studied comparatively with histology, immunohistochemistry, and transmission electron microscopy. In both normal and pathologic specimens, the A1 pulley was composed of two layers: an outer, vascularized, convex layer and an inner, concave, friction, flexor tendon gliding layer. In the latter, the cells and adjacent matrix had several characteristics of fibrocartilage, including chondrocytes. In trigger digits, the number of chondrocytes and adjacent extracellular matrix was significantly increased when compared with controls. There was no evidence of a synovial cell layer on the surface of the A1 pulleys in either normal or trigger digits. We conclude that the underlying pathobiological mechanism for triggering at the A1 pulley is characterized by a fibrocartilage metaplasia.

The role of transforming growth factor beta in Dupuytren's disease.

This study was undertaken to mark immunologically intracellular and extracellular sites of two common transforming growth factor beta (TGF-beta) isoforms, TGF-beta1 and TGF-beta2, in the proliferative, involutional, and residual stages of Dupuytrens disease. The effect of TGF-beta on myofibroblast proliferation was also studied using explant cultures from Dupuytrens nodules in the proliferative or involutional stage. TGF-beta1, TGF-beta2 and the combination of both isoforms were studied at low and high myofibroblast plating densities to simulate respectively proliferative or involutional disease stage conditions. Our results indicate that TGF-beta1 showed an intense intracellular marking pattern associated with fibroblasts, myofibroblasts, and capillary endothelial cells in all Dupuytrens samples, regardless of disease stage. TGF-beta2 showed an intense intracellular localization within myofibroblasts in the proliferative and involutional stages. Fibroblasts in the residual stage did not contain TGF-beta2. Neither isoform was present in the extracellular matrix. Results of cell culture indicate that compared with control myofibroblasts, the addition of TGF-beta1, TGF-beta2 and TGF-beta1 + beta2 had significant effects on myofibroblast proliferation, especially at higher plating densities. However, TGF-beta2 had the most significant proliferative effect.

Collagenase in the treatment of Dupuytren's disease: An in vitro study***

The effects of clostridial collagenase on the tensile strength of Dupuytrens cords was studied in vitro to assess its potential efficacy as an agent for clinical enzymatic fasciotomy. Collagenase was injected into Dupuytrens cords from patients undergoing fascioctomy. Following a pilot experiment, in which a 3,600-unit dose of collagenase induced a 93% decrease in tensile modulus as compared with control cords, groups of five cords each were injected with 150, 300, and 600 units. These cords and a control group of five cords were tested by loading to failure in tension. The ultimate stress and strain to failure were recorded by a video capture technique. All specimens were stained for histologic examination with hematoxylin and eosin for collagen typing with sirrius red. Comparison of the ultimate stress values obtained with published values of extensor forces obtainable by the individual fingers of 40 normal hands indicated that a 300-unit dose of collagenase was sufficient for cord rupture within the average maximum force limits of the extensors of the index, long, ring, and small fingers (p < .02). All samples were in the residual disease stage histologically and contained type I collagen by sirrius red staining. These results indicate that collagenase may be effective in enzymatic fasciotomy of residual-stage Dupuytrens disease.

Platelet-derived growth factor in Dupuytren's disease.

This study investigated whether platelet-derived growth factor, a potent inducer of cell proliferation, was identifiable in association with myofibroblasts in Dupuytrens disease. Myofibroblasts in the hypercellular disease stages showed a strong reaction to platelet-derived growth factor antibody using light and electron microscopic immunochemical labels. Platelet-derived growth factor may play a role as a cellular signal for myofibroblast proliferation in the formation of the pathognomonic nodule in Dupuytrens disease.

Prostaglandins influence myofibroblast contractility in Dupuytren's disease

This study investigated if the vasoactive prostaglandins, PGE2, and PGF2 alpha, were identifiable in association with nodular myofibroblasts of patients with Dupuytrens disease. Immunocytochemic studies, using antibodies specific for these prostaglandins, have confirmed their association with myofibroblasts. Radioimmunoassay was used to quantitate the prostaglandins. Our results indicate a significant increase of both prostaglandins, especially PGF2 alpha, in Dupuytrens palmar fascia when compared with control fascia. These endogenous prostaglandins may influence the contractile behavior of myofibroblasts in Dupuytrens disease to contribute to the pathobiology of this disorder.

Enchondroma protuberans: A case report

Enchondroma protuberans is a rare benign cartilaginous tumor. There have been only 5 cases previously described in the world literature. It must be differentiated from other more common and aggressive tumors to avoid radical resection. A case report of a 7-year-old boy presenting with enchondroma protuberans in the third metacarpal is presented. The patient underwent an initial incisional biopsy followed by a marginal resection of the soft tissue component and intramedullary curettage. After a 36-month follow-up period, there is no evidence of recurrence.

Percutaneous release of A1 pulley.

ABSTRACT We performed 100 percutaneous releases of the trigger digits in a cadaveric model using an 18-gauge needle. Successful percutaneous release was achieved for only 59 digits (59%). No neurovascular injury occurred. We found that a percutaneous trigger digit release resulted in high percentage of incomplete releases of A1 pulley, especially in the thumb, index, and little fingers.

The use of a passive motion machine in the postoperative rehabilitation of Dupuytren's disease

The purpose of this study was to prospectively compare the postoperative use of passive motion (PM) and standard hand therapy after surgical treatment of Dupuytrens disease for extent and rate of recovery of joint motion. Our data indicate that metacarpophalangeal joint contractures improved completely to a mean of 0 degrees, regardless of the postoperative protocol. Contractures at the proximal interphalangeal joint showed incomplete recovery in both study groups, with a mean residual contracture of 28 degrees for PM patients and 38 degrees for control patients. Contractures of the metacarpophalangeal-proximal interphalangeal joints in the same finger showed complete metacarpophalangeal joint recovery to a mean of 0 degrees but incomplete proximal interphalangeal joint recovery with a mean residual contracture of 30 degrees in PM patients and 22 degrees in control patients. We conclude that the use of a PM machine in the rehabilitation of Dupuytrens disease does not offer an advantage in the postoperative management of this condition.

Partial lacerations of median and ulnar nerves

Twelve patients with sharp distal partial median and ulnar nerve lacerations were treated within 2 weeks of injury by end-to-end repair of the lacerated fascicular groups. After an average follow-up of 21 months, the results, based on the British Medical Research Council Rating Scale, were good: S = 3.81 and M = 4.0 (normal: S = 4.0 and M = 5.0). The function of the originally intact fascicular groups did not deteriorate. We suggest that nerve repair of partially lacerated fascicular groups is a reliable treatment method that results in good return of sensory and motor function and does not harm adjacent intact fascicular groups.

HERPETIC WHITLOW WITH BACTERIAL ABSCESS

The herpetic whitlow should be treated nonoperatively. However, a difficult therapeutic dilemma occurs when a whitlow is seen with an established bacterial abscess. We report a case of an adult whose first herpetic whitlow was complicated by secondary periungual abscesses that progressed despite intravenous antimicrobial therapy. Surgical drainage of these periungual abscesses was successfully done in conjunction with intravenous acyclovir with no adverse effects.