Daniel P. Mass

A randomized prospective study of polyglycolic acid conduits for digital nerve reconstruction in humans.

This article reports the first randomized prospective multicenter evaluation of a bioabsorbable conduit for nerve repair. The study enrolled 98 subjects with 136 nerve transections in the hand and prospectively randomized the repair to two groups: standard repair, either end-to-end or with a nerve graft, or repair using a polyglycolic acid conduit. Two-point discrimination was measured by a blinded observer at 3, 6, 9, and 12 months after repair. There were 56 nerves repaired in the control group and 46 nerves repaired with a conduit available for follow-up. Three patients had a partial conduit extrusion as a result of loss of the initially crushed skin flap. The overall results showed no significant difference between the two groups as a whole. In the control group, excellent results were obtained in 43 percent of repairs, good results in 43 percent, and poor results in 14 percent. In those nerves repaired with a conduit, excellent results were obtained in 44 percent, good results in 30 percent, and poor results in 26 percent (p = 0.46). When the sensory recovery was examined with regard to length of nerve gap, however, nerves with gaps of 4 mm or less had better sensation when repaired with a conduit; the mean moving two-point discrimination was 3.7 ± 1.4 mm for polyglycolic acid tube repair and 6.1 ± 3.3 mm for end-to-end repairs (p = 0.03). All injured nerves with deficits of 8 mm or greater were reconstructed with either a nerve graft or a conduit. This subgroup also demonstrated a significant difference in favor of the polyglycolic acid tube. The mean moving two-point discrimination for the conduit was 6.8 ± 3.8 mm, with excellent results obtained in 7 of 17 nerves, whereas the mean moving two-point discrimination for the graft repair was 12.9 ± 2.4 mm, with excellent results obtained in none of the eight nerves (p < 0.001 and p = 0.06, respectively). This investigation demonstrates improved sensation when a conduit repair is used for nerve gaps of 4 mm or less, compared with end-to-end repair of digital nerves. Polyglycolic acid conduit repair also produces results superior to those of a nerve graft for larger nerve gaps and eliminates the donor-site morbidity associated with nerve-graft harvesting.

Direct-current electrical stimulation of tendon healing in vitro

The intrinsic capacity of tendons to heal in response to injury has recently been demonstrated by many investigators. Electrical stimulation is often assumed to augment regeneration of various tissues. Using newly developed methods of whole-tendon culture, the authors examined the effect of direct-current electricity on healing in vitro. Deep flexor tendons of rabbits were excised, transected, repaired, and grown in an acellular culture medium for seven, 14, 21, or 42 days. Tendons through which a continuous 7-microAmp current was passed at the repair site were compared with nonstimulated controls. The incorporation of (14C)proline and its conversion to (14C)hydroxyproline was measured at seven days. The mean (14C)proline and (14C)hydroxyproline activities were 91% and 255% greater, respectively, in the stimulated group. The activity was also higher in the stimulated group, by 42 days. Histologic sections showed that intrinsic tenoblastic repair may be enhanced with electrical stimulation in vitro.

Treatment of painful hand neuromas by their transfer into bone.

Painful neuromas in the hand are not only very disabling for the patient, but difficult to treat. We present the results of 20 painful neuromas treated by burying the neuroma in the bone. Eighteen of the 20 neuromas operated on had acceptable results, according to the criteria of Herndon et al. We present our technique and compare our results with other treatments in the literature.

Dynamic analysis of profundus tendon function

A method for analysis of hand function is reported through evaluation and characterization of flexor digitorum profundus (FDP) tendon mechanics. A testing platform is used that allows for the dynamic evaluation of intact cadaver hand mechanics under normal and pathologic conditions using simultaneous measurements of tendon load, tendon excursion, grip strength, pinch strength, and joint angle. This study of FDP tendons in normal fresh cadaver hands demonstrates that FDP tendon excursion increases as the number and size of joints flexed increases. Extensor counterweighting 500 g, increases FDP tendon load and work but not excursion requirements, and FDP loads of up to 75 N are required for single finger grip strengths of 4 kg force. These loads do not result in permanent (plastic) deformation of either the tendon or the restraining soft tissues. Detailed descriptions of the platform and the mechanical tests performed are provided.

Pyoderma Gangrenosum Mimicking Postoperative Infection in the Extremities. A Report of Two Cases

Pyoderma gangrenosum is an uncommon skin disorder involving ulcerations and necrosis that may occur following an operation and mimic a postoperative infection. We report on two patients who had pyoderma gangrenosum that was not diagnosed initially. Both patients were managed with repeated operative debridement because of a suspected postoperative infection. The diagnosis of pyoderma gangrenosum was eventually established; however, this disorder is not commonly treated by orthopaedic surgeons and is often initially misdiagnosed. CASE 1. A thirty-two-year-old woman was first managed at an outside institution because of pain in the heel and tarsal tunnel syndrome on the right side. At our request, the referring physician provided the patients earlier clinical record so that we could better describe the pertinent history and management in the present report. According to the office notes, the patient was first seen in November 1995 because of a several-month history of severe pain in the right heel. The pain was deep and aching and was worse after walking or prolonged rest. The patient had no relevant medical history and had had no previous operations. There was no family history of rheumatological disorders. Physical examination showed a well perfused foot with palpable dorsalis pedis and posterior tibial pulses. The plantar fascia on the plantar and medial aspects of the heel was tender to palpation. Palpation of the tarsal tunnel was painful, and percussion over the posterior tibial nerve elicited a positive Tinels sign that radiated distally into the plantar aspect of the foot and digits. The symptoms persisted despite treatment with anti-inflammatory medications, orthotics, and a trial of non-weight-bearing with use of crutches, but they did improve temporarily following the use of a Medrol Dosepak (a dose of twenty-eight milligrams of methylprednisolone was given on the first day, and the dose then was decreased by four milligrams …

Human flexor tendon participation in the vitro repair process

This work demonstrates that human flexor tendon segments have the same capabilities to survive culturing and to mobilize an intrinsic healing response as previously described animal models. Segments of human flexor profundus tendons from the flexor tendon sheath were cultured in vitro and analyzed at 1, 2, and 4 weeks by scanning and transmission electron microscopy. The epitenon area thickened during the first week of culture. Fibroblasts migrated over the cut surface of the collagen bundles until they encapsulated the cut end by the second week when new collagen fibrils were seen in the extracellular spaces. By the fourth week, cells in multiple layers covered the cut end of the tendon, both collagen fibrils and new mature collagen bundles were seen. End encapsulation was accomplished by fibroblasts migrating from the outer surface and the interstices of the tendon. The encapsulating cells were active in phagocytosis and collagen synthesis during the entire incubation period.

A randomized biomechanical study of zone II human flexor tendon repairs analyzed in an in vitro model.

To study the effect of dorsally placed flexor tendon repairs on human cadaver tendons, we used the Kessler, Strickland, Robertson, and modified Becker techniques. The strengths of the repairs were tested in a previously described human cadaveric curvilinear model. There were statistically significant increases in dorsal versus volar grasping strength with the Kessler repair (38 N vs 33 N) and the Robertson repair (51 N vs 43 N). There were no differences with the locking Strickland and modified Becker repairs. One may infer that the locking techniques are intrinsically tighter and may not be as susceptible to the different forces between the tensile and compressive surfaces of a dynamic flexor tendon.

The effect of a thigh tourniquet on the incidence of deep venous thrombosis after operations on the fore part of the foot

We performed a prospective randomized clinical study to determine whether use of a thigh tourniquet influences the incidence of deep venous thrombosis. The lower limbs of patients who were scheduled for elective surgery on the fore part of the foot were randomized and assigned to one of three treatment categories: Group I, no tourniquet; Group II, exsanguination by an Esmarch bandage before tourniquet application; and Group III, exsanguination by elevation of the extremity prior to application of a tourniquet. The 117 limbs of seventy-one patients included in this study were evaluated preoperatively and twenty-four and seventy-two hours postoperatively with 125I-labeled fibrinogen, and preoperatively and seventy-two hours postoperatively with Doppler ultrasound studies and phleborheography. The findings in all of the Doppler ultrasound studies and all of the phleborheograms were normal. Two of the 125I-fibrinogen studies were positive, but subsequent contrast venography revealed that these were false-positive findings. We therefore concluded that the use of a thigh tourniquet does not increase the risk of deep venous thrombosis in patients who have had an operation on the fore part of the foot.

Intrinsic healing of the laceration site in human superficialis flexor tendons in vitro

The intrinsic capability of the human superficialis flexor tendon to heal a reapproximated laceration site in vitro was examined. Segments of lacerated and sutured human superficialis flexor tendons from zone II were cultured for two, four, or eight weeks in vitro and analyzed by use of light and electron microscopy. We noted a specific pattern of intrinsic healing at the repair site during the incubation period. After two weeks, the cells of the epitenon from both tendon stumps proliferated and appeared to migrate into the repair site. Elongated cells of the thickened epitenon bridged the laceration and synthesized new collagen fibers. By eight weeks, a smooth contiguous tendon surface was restored and the internal collagen bundles were brought into intimate contact. The fibroblasts bridging the laceration, both in the epitenon and centrally in the repair site, were oriented perpendicular to the cut surfaces. The cells in the repair site were active in protein synthesis, and new collagen fibers were present. No cellular necrosis was observed in the internal repair site. Our results indicate that human superficialis tendons possess an intrinsic capacity to heal with diffusion and without dependence on extratendinous cells or on adhesions.

Operation for collateral ligament ruptures of the metacarpophalangeal joints of the fingers

Ten cases of complete rupture of the collateral ligaments of the metacarpophalangeal finger joints are reported. The nature of this injury, the pre-operative morbidity and the intra-operative pathology are analysed. In all cases surgery was performed with satisfactory results. Operation is indicated for joint stability, grip and pinch strength, pain control and early functional recovery.