Martin I. Boyer

The effect of gap formation at the repair site on the strength and excursion of intrasynovial flexor tendons. An experimental study on the early stages of tendon-healing in dogs.

BACKGROUND Elongation (gap formation) at the repair site has been associated with the formation of adhesions and a poor functional outcome after repair of flexor tendons. Our objectives were to evaluate the prevalence of gap formation in a clinically relevant canine model and to assess the effect of gap size on the range of motion of the digits and the mechanical properties of the tendons. METHODS We performed operative repairs after sharp transection of sixty-four flexor tendons in thirty-two adult dogs. Rehabilitation with passive motion was performed daily until the dogs were killed at ten, twenty-one, or forty-two days postoperatively. Eight tendons ruptured in vivo. In the fifty-six intact specimens, the change in the angles of the proximal and distal interphalangeal joints and the linear excursion of the flexor tendon were measured as a 1.5-newton force was applied to the tendon. The gap at the repair site was then measured, and the isolated tendons were tested to failure in tension. RESULTS Twenty-nine tendons had a gap of less than one millimeter, twelve had a gap of one to three millimeters, and fifteen had a gap of more than three millimeters. Neither the time after the repair nor the size of the gap was found to have a significant effect on motion parameters (p > 0.05); however, the ultimate force, repair-site rigidity, and repair-site strain at twenty newtons were significantly affected by these parameters (p < 0.05). Testing of the tendons with a gap of three millimeters or less revealed that, compared with the ten-day specimens, the forty-two-day specimens failed at a significantly (90 percent) higher force (p < 0.01) and had a significantly (320 percent) increased rigidity (p < 0.01) and a significantly (60 percent) decreased strain at twenty newtons (p < 0.05). In contrast, the tensile properties of the tendons that had a gap of more than three millimeters did not change significantly with time. CONCLUSIONS Our data indicate that, in a dog model involving sharp transection followed by repair, a gap at the repair site of more than three millimeters does not increase the prevalence of adhesions or impair the range of motion but does prevent the accrual of strength and stiffness that normally occurs with time.

Scaphoid Nonunion with Avascular Necrosis of the Proximal Pole Treatment with a vascularized bone graft from the dorsum of the distal radius

Scaphoid nonunion with avascular necrosis of the proximal pole remains a difficult problem. We have endeavoured to heal the fracture, restore scaphoid height and revascularize the proximal pole of the scaphoid by means of a vascularized dorsal interposition graft from the distal radius. The procedure has resulted in union of six of ten fractures. Fractures that healed had not been treated by a previous bone grafting procedure. Dissatisfaction was due to loss of motion in patients who had healed fractures, and pain in those patients with persistent non-unions.

Treatment of distal radius fractures

The clinical practice guideline is based on a systematic review of published studies on the treatment of distal radius fractures in adults. None of the 29 recommendations made by the work group was graded as strong; most are graded as inconclusive or consensus; seven are graded as weak. The remaining five moderate-strength recommendations include surgical fixation, rather than cast fixation, for fractures with postreduction radial shortening >3 mm, dorsal tilt >10 degrees , or intra-articular displacement or step-off >2 mm; use of rigid immobilization rather than removable splints for nonsurgical treatment; making a postreduction true lateral radiograph of the carpus to assess dorsal radial ulnar joint alignment; beginning early wrist motion following stable fixation; and recommending adjuvant treatment with vitamin C to prevent disproportionate pain.

Intrasynovial flexor tendon repair: An experimental study comparing low and high levels of in vivo force during rehabilitation in canines

Background: Rehabilitation methods that generate increased tendon force and motion have been advocated to improve results following intrasynovial flexor tendon repair. However, the effects of rehabilitation force and motion on tendon-healing may be masked by the high stiffness produced by newer suture methods. Our objective was to determine whether the biomechanical properties of tendons repaired by one of two multistrand suture methods were sensitive to an increased level of applied rehabilitation force. Methods: Two hundred and fourteen flexor digitorum profundus tendons from 107 adult dogs were transected and repaired. Dogs were assigned to one of four groups based on the rehabilitation method (low force [<5 N] or high force [17 N]) and the repair technique (four-strand or eight-strand core suture) and were killed between five and forty-two days after the procedure. Repair-site structural properties were determined by tensile testing, and digital range of motion was assessed with use of a motion-analysis system. Results: Tensile properties did not differ between the low and high-force rehabilitation groups, regardless of the repair technique (p > 0.05). In contrast, tensile properties were strongly affected by the repair technique, with tendons in the eight-strand group having an approximately 35% increase in ultimate force and rigidity compared with those in the four-strand group (p < 0.05). Ultimate force did not change significantly with time during the first twenty-one days (p > 0.05); there was no evidence of softening in either of the repair or rehabilitation groups. Force increased significantly from twenty-one to forty-two days, while rigidity increased throughout the forty-two-day period (p < 0.05). Conclusions: Increasing the level of force applied during postoperative rehabilitation from 5 to 17 N did not accelerate the time-dependent accrual of stiffness or strength. Suture technique was of primary importance in providing a stiff and strong repair throughout the early healing interval. Clinical Relevance: Our findings suggest that there be a reexamination of the concept that increases in force produced by more vigorous mobilization protocols are beneficial to tendon-healing. While more vigorous rehabilitation may help to improve hand function, we found no evidence that it enhances tissue-healing or strength in the context of a modern suture repair.

Flexor tendon repair and rehabilitation: state of the art in 2002.

Basic science and clinical investigation have advanced significantly the treatment and the outcome following intrasynovial flexor tendon repair and rehabilitation and reconstruction over the past 30 years. The application of modern multistrand suture repair techniques as well as postoperative rehabilitation protocols emphasizing the application of intrasynovial repair site excursion has led to a protocol for treatment of intrasynovial flexor tendon lacerations emphasizing a strong initial repair followed by the application of postoperative passive motion rehabilitation. Protocols for the reconstruction of failed initial treatment have likewise undergone modification given new findings on the biologic and clinical behavior of flexor tendon grafts. Currently accepted treatment protocols following flexor tendon repair and reconstruction are based on current clinical and scientific data.

Quantitative variation in vascular endothelial growth factor mRNA expression during early flexor tendon healing: an investigation in a canine model

Vascular endothelial growth factor (VEGF) is a potent mediator of angiogenesis, with direct mitogenic activity on cells of endothelial origin. We quantified the temporal accumulation of VEGF mRNA at the repair site of an in vivo canine intrasynovial flexor tendon repair and rehabilitation model by means of quantitative Northern blot analysis, in order to detail a molecular signal involved in the intrinsic angiogenic process that accompanies early flexor tendon healing. Significant accumulation of VEGF mRNA occurred at the flexor tendon repair site at 7 days post‐operatively, with peak levels seen at post‐operative days 7 and 10. Levels returned to baseline by day 14.

The insertion site of the canine flexor digitorum profundus tendon heals slowly following injury and suture repair

Treatment of injuries of the flexor digitorum profundus (FDP) tendon insertion site has changed little during the past 50 years, in part because there are no reports describing flexor tendon insertion site healing. Our objective was to assess the effects of repair technique and post‐operative time on tendon–bone healing using a canine model of injury and repair. We transected 48 FDP tendons from 24 dogs at their insertions and repaired them using either a four‐ or eight‐strand suture technique. We assessed the mechanical properties of the repaired tendon–bone construct, tendon collagen biochemistry, and distal phalanx bone mineral density (BMD) at 0, 10, 21 and 42 days. Suture method had no significant effect on any outcome (p > 0.05). In particular, use of an eight‐strand double modified Kessler technique did not result in increased stiffness or strength compared to a four‐strand technique. With time, the repair site became stiffer, as demonstrated by a 230% increase in rigidity and a 50% decrease in strain from 0 to 42 days. However, from 0 to 42 days the ultimate force of the insertion site did not increase. This lack of increase in ultimate force was consistent with decreases in collagen content, non‐reducible crosslinks and distal phalanx BMD. Taken together, our results indicate that the canine FDP tendon heals slowly after it is injured at its insertion site and sutured onto the distal phalanx. While these findings may be limited to the particular repair method we used, they demonstrate a need for devising new treatment strategies to improve healing of flexor tendon insertion site injuries.

Corticosteroid injection in diabetic patients with trigger finger. A prospective, randomized, controlled double-blinded study.

BACKGROUND It is generally accepted that the initial treatment for trigger finger is injection of corticosteroid into the flexor tendon sheath. In this study, the efficacy of corticosteroid injections for the treatment of trigger finger in patients with diabetes mellitus was evaluated in a prospective, randomized, controlled, double-blinded fashion and the efficacy in nondiabetic patients was evaluated in a prospective, unblinded fashion. METHODS Thirty diabetic patients (thirty-five digits) and twenty-nine nondiabetic patients (twenty-nine digits) were enrolled. The nondiabetic patients were given corticosteroid injections in an unblinded manner. The cohort with diabetes was randomized into a corticosteroid group (twenty digits) or a placebo group (fifteen digits). Both of these groups were double-blinded. Additional injections, surgical intervention, and recurrent symptoms of trigger finger were recorded. Treatment success was defined as complete or nearly complete resolution of trigger finger symptoms such that surgical intervention was not required. RESULTS After one or two injections, twenty-five of the twenty-nine digits in the nondiabetic group had a successful outcome compared with twelve of the nineteen in the diabetic corticosteroid group (p = 0.03) and eight of the fifteen in the diabetic placebo group (p = 0.006). With the numbers studied, no significant difference was found between the diabetic groups. Surgery was performed in three of the twenty-nine digits in the nondiabetic group compared with seven of the nineteen in the diabetic corticosteroid group and six of the fifteen in the diabetic placebo group. There was a significant difference in the prevalence of surgery between the nondiabetic group and both the diabetic corticosteroid group and the diabetic placebo group (p = 0.035 and p = 0.020, respectively). With the numbers studied, no difference was found between the diabetic groups with regard to the persistence of symptoms. Nephropathy and neuropathy were significantly associated with the need for surgery (p = 0.008 and p = 0.03, respectively). CONCLUSIONS Corticosteroid injections were significantly more effective in the digits of nondiabetic patients than in those of diabetic patients. In patients with diabetes, corticosteroid injections did not decrease the surgery rate or improve symptom relief compared with the placebo. The use of corticosteroid injections for the treatment of trigger finger may be less effective in patients with systemic manifestations of diabetes mellitus.

Ulnar and Median Nerve Palsy in Long-distance Cyclists A Prospective Study

Background Although case reports have identified the presence of distal ulnar nerve sensory and motor dysfunction in long-distance cyclists, the actual incidence of this condition, referred to as “cyclists palsy,” is unknown. Purpose To determine the incidence of distal ulnar nerve compression in cyclists. Study Design Prospective study. Methods Twenty-five road or mountain bike riders responded to a questionnaire and were then physically examined and interviewed before and after a 600-km bicycle ride. Results Twenty-three of the 25 cyclists experienced either motor or sensory symptoms, or both. Motor symptoms alone occurred in 36% of the hands (11 cyclists) tested; no significant difference in the incidence of motor symptoms was found among cyclists of various experience levels or based on handlebar types (mountain bike versus road bike). Sensory symptoms alone occurred in 10% of hands (four cyclists) tested, with the majority of these being in the ulnar distribution. A significantly higher proportion of mountain bike riders had sensory deficits compared with road bike riders; however, there was no significant difference in the occurrence of sensory deficits based on level of experience. A total of 24% of the hands (eight cyclists) tested experienced a combination of motor and sensory symptoms. These motor and sensory symptoms were equally distributed between road bike riders and mountain bike riders and riders of various experience levels. Conclusions Cyclists palsy occurs at high rates in both experienced and inexperienced cylists. Steps may be taken to decrease the incidence of cyclists palsy; these include wearing cycling gloves, ensuring proper bicycle fit, and frequently changing hand position.

Sonography of the hand and wrist.

Not only is the anatomy of the hand and wrist complex, but also its pathologic conditions are quite diverse. Although plain radiographs, CT, arthrography, and MRI have traditionally been used to evaluate the hand and wrist, ultrasound is beginning to take its place alongside these more traditional imaging modalities and is being ordered with increasing frequency by orthopedic surgeons. This article reviews the pertinent gross anatomy and sonographic technique used to scan the hand and wrist and also describes the sonographic findings associated with the most common hand and wrist pathologic conditions. These include soft tissue tumors, tenosynovitis, tendinous and ligamentous injuries of the hand, Dupuytrens contracture, foreign bodies, and carpal tunnel syndrome (CTS).