James M. Hunter

Fifth Metacarpal Fractures in a Compensation Clinic Population: A Report On One Hundred And Thirty-three Cases

One hundred and thirty-three fractures of the fifth metacarpal were reviewed in patients attending a city compensation clinic. Splinting of the hand in a functional position for ten days (except in cases of displaced mid-shaft fractures) followed by mobilization and early use of the hand has proved to be a method of treatment that leads to early return to active duty with a full functional hand. The majority of the fractures involved the metacarpal head and neck and were considered stable impacted fractures. Angulation of up to 40 degrees was accepted without reduction and if easy reduction under local anesthesia was not obtained, angulation of up to 70 degrees was accepted, provided there was not excessive rotation of the distal fragment. This angulation is reflected in mild clinical deformity and has proved not to interfere with normal use of the hand, nor has it resulted in patient dissatisfaction. The complications that result from more exacting methods of treatment are briefly reviewed.

Two-stage flexor-tendon reconstruction. Ten-year experience.

One hundred and fifty fingers in 136 patients were treated by a two-stage flexor-tendon reconstruction and followed for an average of 2.4 years. A salvage procedure such as this was needed for most of these fingers since 81 per cent of the injuries were in Zone 2 and 45 per cent were Grade 5 in severity. Before reconstruction, the mean total active motion (all joints combined) for each finger was 102 degrees and the mean grip strength was 20 per cent of normal. At final follow-up, the mean total active motion of these fingers was 176 degrees and the mean grip strength was 79 per cent of normal. Three months after tendon-grafting, the results had reached a plateau, and no significant change occurred thereafter. Complications were a flexion contracture of varying degree in 41 per cent of the fingers, especially when a contracture was present preoperatively (40 per cent); rupture of the tendon graft in 14 per cent; and infection in 4 per cent. This review reaffirmed the usefulness of two-stage flexor-tendon reconstruction as a salvage procedure to restore function of flexor tendons.

Flexor tendon gliding in the hand. Part I. In vivo excursions

The amplitude of gliding of the flexor tendons was measured in 36 hands tagged intraoperatively with buried wire sutures. Finger and wrist position was correlated with tendon excursion as measured on radiographs in the postoperative period. With the wrist in the neutral position, the superficialis tendon achieved an excursion of 24 mm and the profundus tendon 32 mm. Excursion of the flexor pollicis longus tendon was 27 mm. With wrist range of motion, the amplitude of the superficialis tendon became 49 mm, the profundus tendon 50 mm, and the flexor pollicis longus tendon 35 mm.

Flexor tendon gliding in the hand. Part II. Differential gliding.

Flexor tendon gliding was studied in vivo in 48 hands. Three finger motions--straight-fist, hook, and fist--were found to provide maximum differential gliding for superficialis and profundus tendons in respect to each other, as well as in respect to the flexor sheath and bone.

Staged flexor tendon reconstruction

Attempts to reconstruct a scarred tendon system with a one-stage tendon graft have frequently resulted in failure, particularly in the complex flexor system. One of the most challenging aspects of reconstructive hand surgery is the restoration of good function of the damaged tendon motor system. Restitution of a stiff, scarred tendon complex to a gliding, pliable state can be accomplished by a carefully planned two-stage tendon graft program 1. 2 that uses a flexible silicone tendon implant at the first stage. Restoration of the damaged fibro-osseous canal by reconstruction of new pulleys around the gliding tendon implant results in improved gliding mechanics. A fluid nutrition system is induced that can nourish a gliding implant and subsequently allow second-stage free tendon grafting. 6 This discussion reviews the ongoing experience with flexor tendon reconstruction at our Hand Center. The technique and management advances that have resulted in improved results will be discussed.

Biomechanics of pulley reconstruction

The biomechanics of the reconstructed flexor retinacular pulley system are poorly defined. We used a mathematical theoretical model, confirmed by a cadaver model, and a clinical radiographic model to evaluate a variety of different joint and pulley combinations. We examined twenty-four sets of radiographs of 12 fingers in 9 patients for whom excursion was measured and predicted by the mathematical model. The 30 pulley combinations evaluated in the in vitro cadaver model showed statistical correlation with the biomechanical mathematical model. Recommendations of clinical application on the basis of this information include the following: (1) Two pulleys should be placed, one proximal and one distal to each joint. (2) These two pulleys should be balanced about the joint axis both in distance from the axis and in pulley height. (3) They should be positioned at the edge of the flare of the metaphysis. (4) The three individual joints can be balanced, one to another, by maintaining minimal bowstringing at all three joints. In this way, the relative excursion at the joint and torque at the joint will be maintained in a physiological ratio as close to normal as possible.

The effect of vincular injury on the results of flexor tendon surgery in zone 2

From a consecutive series of 82 fingers (69 patients) that sustained flexor tendon lacerations in zone 2, 47 fingers (39 patients) had the status of the vincular system determined during primary repair. The vincula were intact in 22 fingers and not intact in 25. Total active motion (TAM) after rehabilitation and before a reconstructive procedure, such as repair of a rupture, tenolysis, or grafting of a tendon, was the end point of the study. The overall mean TAM was 196 degrees. The mean TAM was 222 degrees for fingers with intact vincula and 176 degrees for fingers with vincula not intact (p less than 0.01). There were no statistical differences between the two groups regarding surgical results when the number of tendons injured per finger and sheath closure were analyzed. This study suggests that the integrity of the vincular system is a determinant of end result TAM and flexor tendon lacerations in zone 2.

Conservative Management of the Trigger Finger: A New Approach

Abstract The purpose of this paper is to present a new conservative approach for treatment of the trigger finger based on the premise that, by altering mechanical pressures of the proximal pulley system and by encouraging maximal differential tendon gliding, the pathological state of the tendon and sheath can be reversed in a significant number of cases with no other treatment. A program of splinting is described in which the metacarpophalangeal joints are immobilized at 0° extension, relieving friction between tendon and pulley system by altering flexor biomechanics. Acute proximal interphalangeal flexion exercises are prescribed to encourage synovial diffusion, lymphatic drainage, and maximum differential tendon excursion within the sheath. Fifty-five digits in 35 nonrheumatoid hands were treated with the described technique. No other treatment was necessary for 73% of the patients, suggesting that this technique should be considered prior to injection or surgery.

Active tendon implants in flexor tendon reconstruction

Forty-five active flexor tendon implants were evaluated after placement in scarred tendon beds of digits II through V. The implant is constructed of silicone rubber with a Dacron core, terminating in a loop proximally and a metal plate distally. Modification of the implant during the period of study has improved its reliability and longevity. The improvement in total active motion (TAM) averaged 72 degrees during implant functioning (stage I) in a group of digits that before operation were classified as 78% Boyes grade 5 (salvage). Complication rate during stage I was 11% (5 out of 45). Of the 27 digits evaluated after implant replacement by tendon autograft (stage II), there was an overall improvement in 62 degrees total active motion with 70% of digits being Boyes grade 5. Many of the complications were believed to be avoidable with experience. This study demonstrates the feasibility of an active tendon implant and the possibility of a permanent prosthesis.

The pseudosynovial sheath—Its characteristics in a primate model

The characteristics and long-term fate of the pseudosynovial sheath formed in response to a gliding tendon implant were examined. A primate model was chosen to reproduce the human clinical situation. Hunter passive gliding implants were implanted in 32 digits of eight Macque monkeys. Surgical syndactylism was created to the adjacent active digits to provide passive range of motion of the digits. No implanted digits demonstrated progressive flexion contractures. Radiographs revealed passive excursion of the implants of an average of 2.5 cm. Biopsies were taken at various time intervals and locations for histological examination. The pseudosynovial sheath has three descriptive layers: an intima, media, and adventitia. This sheath becomes mature and stable at 8 weeks. The intima cells contain a glycosaminoglycan substance and have a secretory capacity. The media cells have large amounts of collagen and provide structural and vascular support. The adventitia is a highly vascular structure composed of loose fibrous tissues that demonstrates clefts that may represent gliding planes. The pseudosynovial sheath was found to be a morphologically stable structure that showed no propensity for longitudinal contracture. The sheath appears to have the characteristics necessary to provide a good bed for a tendon graft.