John G. Seiler

The distal biceps tendon: Two potential mechanisms involved in its rupture: Arterial supply and mechanical impingement

The purpose of this anatomic study was to evaluate potential causes of rupture of the distal biceps tendon, to assess the dynamic relationship of the proximal radioulnar joint during pronation and supination, and to identify potential sites of impingement of the distal biceps tendon. For the anatomic study specimens were evaluated by light microscopy, multiplanar gross dissections, and Spalteholz vascular injection. For the radiographic study computed tomography was used to assess dynamic changes in the radioulnar space in pronation, neutral position, and supination. Three vascular zones were identified in the distal biceps tendon. Vascular contributions were consistently noted from the brachial artery proximally and from the posterior recurrent artery distally. A hypovascular zone averaging 2.14 cm was evident between the proximal and distal zones. On sectioning through the proximal radioulnar joint 85% of the space was occupied by the distal tendon in full pronation. In addition, computed tomography imaging revealed a 50% reduction in the radioulnar joint at the radial tuberosity from full supination to full pronation. Mechanical impingement on the biceps tendon during forearm rotation and hypovascularity within sections of the tendon may contribute to attritional ruptures of the distal biceps tendon.

The effects of multiple-strand suture methods on the strength and excusion of repaired intrasynovial flexor tendons: A biomechanical study in dogs

This study was designed to determine the effects of in vivo multistrand, multigrasp suture techniques on the strength and gliding of repaired intrasynovial tendons when controlled passive motion rehabilitation was used. Twenty-four adult mongrel dogs were divided into 4 groups and their medial and lateral forepaw flexor tendons were transsected and sutured by either the Savage, the Tajima, the Kessler, or the recently developed 8-strand suture method. The tendon excursion, joint rotation, and tensile properties of the repaired tendons were evaluated biomechanically at 3 and 6 weeks after surgery. It was found that neither time nor suture method significantly effected proximal and distal interphalangeal joint rotation or tendon excursion when the 4 techniques were compared to each other. Normalized load value (experimental/control) was significantly affected by both the suture method and the amount of time after surgery, however. The Savage and 8-strand repair methods had significantly greater strength than did the Tajima method at each time interval (p < .05 for each comparison). In addition, the 8-strand method had significantly greater normalized load values than did the Savage method at each time interval (p < .05 for each comparison). Normalized stiffness (experimental/control) for the 8-strand repair method was significantly greater than that for the Tajima and Savage methods at 3 and 6 weeks after surgery (p < .05). In addition, the normalized stiffness values for the 6-week groups was significantly greater than those for the 3-week groups (p < .05). It was concluded that the method of tendon suture was a significant variable insofar as the regaining of tendon strength was concerned and that the newer low-profile 8-strand repair method significantly expands the safety zone for the application of increased in vivo load during the early stages of rehabilitation.

Growth factors and canine flexor tendon healing: Initial studies in uninjured and repair models***

The role of growth factors in a variety of bone and soft tissue healing processes has been studied extensively in numerous recent models, yet little is known about the specific growth factors that may be playing a role in flexor tendon healing. We used a number of established protein purification techniques and bioassays to isolate and partially characterize a heparin-binding growth factor from unoperated canine tendons. Our data provide evidence that basic fibroblast growth factor, a potent angiogenic growth factor, is present in normal canine intrasynovial flexor tendons. We then studied repaired canine flexor tendons to further elucidate the role of growth factors in the tendon healing process. Heparin-sepharose elution profiles from three repair intervals (3, 10, and 17 days) were graphed and compared to known profiles of isolated growth factors. The three repair intervals demonstrated two elution profile peaks, consistent with varying amounts of platelet-derived growth factor and epidermal growth factor. Although additional experimentation is required to identify definitively the various protein isolates, these data provide compelling evidence that a variety of growth factors are present in uninjured and healing digital flexor tendons.

Operative management of displaced femoral head fractures: case-matched comparison of anterior versus posterior approaches for Pipkin I and Pipkin II fractures.

Summary Because of the controversy surrounding the selection of the surgical approach for the operative management of femoral head fractures, we retrospectively reviewed the combined experience with femoral head fractures at two major trauma centers. Forty-three femoral head fractures in 41 patients were identified. Twenty-six of the 43 fractures were Pipkin types I and II, and were managed operatively. Of the 26 patients, 12 with >2 years of follow-up were managed with posterior surgical approaches and 12 with anterior surgical approaches. These patients were assessed with respect to operative time, estimated blood loss and function, and the radiographs for reduction, avascular necrosis, and heterotopic ossification. There was a significant decrease in operative time, estimated blood loss, and improved visualization and fixation with the anterior approach: however, there was a significant increase in functionally significant heterotopic ossification. The functional results in the two groups were identical; 67% good and excellent in each. There were no cases of avascular necrosis of the femoral head associated with an anterior approach. Because of the greater ease of access to the fracture, the anterior approach is recommended when operative reduction of a displaced Pipkin type I or II is indicated, but newer methods of minimizing heterotopic ossification must be developed.

Zone-II Flexor Tendon Repair: A Randomized Prospective Trial of Active Place-and-Hold Therapy Compared with Passive Motion Therapy

BACKGROUND In order to improve digit motion after zone-II flexor tendon repair, rehabilitation programs have promoted either passive motion or active motion therapy. To our knowledge, no prospective randomized trial has compared the two techniques. Our objective was to compare the results of patients treated with an active therapy program and those treated with a passive motion protocol following zone-II flexor tendon repair. METHODS Between January 1996 and December 2002, 103 patients (119 digits) with zone-II flexor tendon repairs were randomized to either early active motion with place and hold or a passive motion protocol. Range of motion was measured at six, twelve, twenty-six, and fifty-two weeks following repair. Dexterity tests were performed, and the Disabilities of the Arm, Shoulder, and Hand (DASH) outcome questionnaire and a satisfaction score were completed at fifty-two weeks by ninety-three patients (106 injured digits). RESULTS At all time points, patients treated with the active motion program had greater interphalangeal joint motion. At the time of the final follow-up, the interphalangeal joint motion in the active place-and-hold group was a mean (and standard deviation) of 156 degrees +/- 25 degrees compared with 128 degrees +/- 22 degrees (p < 0.05) in the passive motion group. The active motion group had both significantly smaller flexion contractures and greater satisfaction scores (p < 0.05). We could identify no difference between the groups in terms of the DASH scores or dexterity tests. When the groups were stratified, those who were smokers or had a concomitant nerve injury or multiple digit injuries had less range of motion, larger flexion contractures, and decreased satisfaction scores compared with patients without these comorbidities. Treatment by a certified hand therapist resulted in better range of motion with smaller flexion contractures. Two digits in each group had tendon ruptures following repair. CONCLUSIONS Active motion therapy provides greater active finger motion than passive motion therapy after zone-II flexor tendon repair without increasing the risk of tendon rupture. Concomitant nerve injuries, multiple digit injuries, and a history of smoking negatively impact the final outcome of tendon repairs.

Endoscopic carpal tunnel release: An anatomic study of the two-incision method in human cadavers

To determine the relationship of neurovascular structures to the sites of portal placement and transverse carpal ligament division during two-portal endoscopic carpal tunnel release, a study of 20 fresh cadaver specimens was carried out. Open dissection of the carpal tunnel after endoscopic surgery showed complete ligamentous release in 18 hands (90%). In 10 specimens, the procedure was performed as described by Chow. There was one partial transection of the superficial palmar arch (5%), and five specimens (50%) had complete divisions of the superficial palmar fascia with considerable pressure placed on the ulnar nerve at the wrist. A modified technique was used in 10 specimens in which the proximal incision was made in a more distal location and a distally based ligamentous flap was created. The superficial palmar arch and the distal edge of the transverse carpal ligament were visualized directly before passage of the trocar. No complications were noted with this method.

The cutaneous innervation of the palm: An anatomic study of the ulnar and median nerves†

Twenty-five fresh-frozen cadaveric hands without obvious deformity were dissected using 3.5x loupe magnification. Median and ulnar nerves were identified in the proximal forearm and dissected distally to the midpalm. Cutaneous branches of median and ulnar nerves were described relative to an incision for carpal tunnel release. The palmar cutaneous branch of the median nerve was present in all 25 specimens. In a single specimen, the palmar cutaneous branch of the median nerve was isolated as it crossed the incision, and in another two specimens, the terminal branches of the nerve were identified at the margin of the incision. In 4 hands, a classic palmar cutaneous branch of the ulnar nerve was found an average of 4.9 cm proximal to the pisiform. In 10 specimens, a nerve of Henle arose an average of 14.0 cm proximal to the pisiform and traveled with the ulnar neurovascular bundle to the wrist flexion crease. In 24 specimens, at least one-usually multiple-transverse palmar cutaneous branch was identified originating an average of 3 mm distal to the pisiform within Guyons canal. The origin and destination of these nerves was highly variable. In 16 specimens, an incision in the axis of the ring finger would likely have encountered at least one branch of the ulnar-based cutaneous innervation to the palm. Cutaneous branches of the ulnar nerve would be expected to cross the line of dissection frequently during open carpal tunnel release. Decreased levels of discomfort in patients undergoing endoscopic and subcutaneous types of carpal tunnel release may be in part due to the preservation of the crossing cutaneous nerves with these procedures.

The Marshall R. Urist Young Investigator Award

To examine the hypothesis that different types of dense regular connective tissue may have different repair mechanisms within the synovial space, intrasynovial and extrasynovial autogenous donor flexor tendon grafts were placed within the synovial sheaths of the medial and lateral forepaw digits of dogs. Histologic, ultrastructural, biochemical, and biomechanical analyses were done between 10 days and 6 weeks after tendon grafting. Intrasynovial tendon grafts remained viable when transferred to the synovial space and appeared to heal through an intrinsic process with preservation of the gliding surface and improved functional characteristics. Extrasynovial tendon grafts functioned as a scaffolding for the early ingrowth of new vessels and cells. Early cellular necrosis consistently was followed by the ingrowth of fibrovascular adhesions from the periphery. The formation of dense peripheral adhesions, obliterating the gliding surface of the tendon, led to diminished tendon excursion and proximal interphalangeal joint rotation.

The application of the limited contact dynamic compression plate in the upper extremity: an analysis of 114 consecutive cases

We sought to assess the clinical effectiveness of a new plate design which offers improved biological and biomechanical features, the limited contact dynamic compression (LCDC) plate. We analysed 114 LCDC plates applied consecutively for upper extremity fractures or reconstruction in 94 patients. Three patients were lost to follow-up, leaving 111 plates in 91 patients followed to definitive fracture/osteotomy outcome. Thirty-seven plates were applied for reconstruction in 35 patients, including 11 where standard implants had failed. Fifty-six patients had 74 plates applied for acute fractures including 12 open fractures, 23 multiply injured patients, 26 patients with concomitant fractures and seven associated neurovascular injuries. All patients were followed to definitive outcome. Union was achieved at an average of 10.7 weeks in 105 platings, while three delayed unions eventually united without further intervention, an overall union rate of 108/111, or 97.3 per cent. There were no mechanical failures of the plates or screws. In this large series a union rate of 97.3 per cent with no implant failures confirms its clinical application for traumatic and reconstructive problems in this area. Improved contouring, easier screw placement, decreased interference with cortical bone blood flow and excellent union rates are definite short-term advantages. Theoretical long-term benefits of decreased stress-shielding and lower refracture rates will require longer follow up.

Publication rates of abstracts presented at the 1993 annual Academy meeting.

What percent of abstracts presented at the American Academy of Orthopaedic Surgeons annual meeting are submitted, survive peer review, and eventually are published? The answer to this fundamental question is important because many national meeting attendees use the unscrutinized information that is presented to alter their surgical practices. At the 1993 American Academy of Orthopaedic Surgeons meeting, 573 abstracts were presented. After a 5-year period, 44% of abstracts presented were published as papers in a peer reviewed journal. The results suggest that for various reasons, the majority of presented material at the Academy meeting has not been authenticated scientifically to be as accurate as papers that survive the rigors of peer review.