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Biomedical subjects

Martin I Boyer

Publications and source records attributed to Martin I Boyer.

31 records · Page 2Linked to original sources
PubMed2003

The Lichtman classification for Kienböck's disease: an assessment of reliability.

PURPOSE: The correct identification of Lichtman stage 3A and 3B Kienböck's disease is crucial for treatment purposes. The present study evaluates the reliability of the Lichtman classification, with specific attention to differentiating stage 3A and 3B. METHODS: Four reviewers evaluated wrist radiographs from 39 patients with Kienböck's disease. Radiographs were graded according to the traditional Lichtman classification, a modification of the Lichtman classification using a radioscaphoid angle of 60 degrees to subdivide stage 3, and 8 other radiographic measures. RESULTS: The interobserver reliability of the Lichtman classification was substantial (kappa coefficient 0.63), but Stage 3A was less reliably identified (kappa 0.38). The new modification of the Lichtman classification increased both the overall (kappa 0.81) and the stage 3A (kappa 0.75) interobserver reliability. CONCLUSION: The use of the radioscaphoid angle increases the interobserver reliability of the Lichtman classification. This should allow a better understanding of the clinically important distinction between stage 3A and 3B disease.

Humans↗
PubMed2003

Two-portal repair of canine flexor tendon insertion site injuries: histologic and immunohistochemical characterization of healing during the early postoperative period.

PURPOSE: In vivo animal studies have indicated that the complex structure of the tendon-bone interface may not be restored after repair even under optimal conditions. Controversy exists about the histologic findings in the early postoperative period after tendon reattachment to bone; this may have impact on biomechanical properties. The objective was to study the histologic structure and immunohistochemical staining of the tendon-bone interface in a large model of digital flexor tendon-bone repair. The hypothesis was that the tendon-bone interface matures and assumes a progressively more anatomic histologic and immunohistochemical appearance during the first 6 weeks after repair. METHODS: Twenty-four canine flexor digitorum profundus tendons were released from their insertion by sharp dissection and repaired to bone. The forelimb was immobilized after surgery and 10 minutes of daily passive motion rehabilitation was performed. Dogs were killed at 10, 21, and 42 days after surgery. Hematoxylin-eosin and immunohistochemical staining for types I, II, and II collagen were performed. RESULTS: Although at both 10 and 21 days after surgery substantial inflammation was seen at the tendon-bone repair site, this had decreased markedly by 42 days. Although direct apposition of tendon to bone was seen at 42 days, the mature tendon-bone insertion site was not recreated by this time. Staining for types I and III collagen was diffuse throughout the tendon-bone insertion throughout the interval examined. CONCLUSION: These findings suggest that at 6 weeks after surgery the intact tendon-bone repair site shows minimal histologic and molecular similarity when compared with unoperated specimens.

Animals↗
PubMed2003

Eight-strand core suture technique for repair of intrasynovial flexor tendon lacerations.

The concept of intrinsic tendon healing, the idea that tendons can heal primarily without the ingrowth of fibrous adhesions from the surrounding fibrous flexor sheath, has been validated both experimentally and clinically. The goals of the surgical treatment of intrasynovial digital flexor tendon lacerations are twofold: 1) to achieve a primary tendon repair of sufficient strength so as to prevent repair site gap elongation and possible rupture, and 2) to prevent the formation of intrasynovial adhesions that cause loss of tendon excursion within the flexor tendon sheath. It is well accepted that repair site strength, both at time zero and within the first 6 postoperative weeks, is directly related to the number of core suture strands crossing the repair site. The factor that limits more widespread use of multistrand suture techniques remains the surgeon's ability to perform the repair while also minimizing trauma to the tendon stumps and the circumferential epitenon. We describe an 8-strand core suture technique used at our institution that has been tested ex-vivo, in-vivo in canines, and used in human subjects over the last 4 years with excellent results.

Journal Article↗
PubMed2003

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.

Hand Injuries↗
PubMed2003

Intra-articular fractures of the upper extremity: new concepts in surgical treatment.

New techniques of internal fixation, postoperative rehabilitation, and emphasis on functional as well as radiographic outcome have refined the surgical treatment of complex fractures of the glenoid, humeral head, supracondylar and intracondylar humerus, olecranon, radial head, distal radius, and distal radioulnar joint over the past decade. Early stabilization and rehabilitation of these injuries leads to soft-tissue stabilization and facilitates the patient's ability to place the hand in three-dimensional space.

Arthroplasty↗
PubMed2002

Recent progress in flexor tendon healing.

Although advances in the treatment of flexor tendon injuries have led to improved clinical outcomes during the past several decades, a subset of patients continue to experience a loss of function. Using a canine model of sharp transection of the flexor digitorum profundus tendon followed by repair and rehabilitation using clinically relevant techniques, we have examined the influence of multistrand suture and postoperative rehabilitation variables on digital function and tendon strength. Our findings highlight the critical role of repair technique in providing a stiff and strong repair and indicate that continued refinement of suture techniques is warranted in order to minimize repair-site elongation (gap). Gap formation continues to occur at a high frequency, and the formation of gaps greater than 3 mm delays the accrual of repair-site strength that occurs with time. Furthermore, our results indicate that passive-motion rehabilitation that produces a moderate amount of tendon excursion (2 mm) at low levels of tendon force (5 N) is sufficient to inhibit adhesion formation and to promote healing. Increases in excursion or force beyond these levels do not accelerate the healing process. These findings suggest that we are approaching the limit of the extent to which we can modulate healing by manipulating rehabilitation variables such as tendon excursion and force. Future advances will probably require manipulation of the biological factors that promote healing.

Animals↗
PubMed2002

The rigidity of repaired flexor tendons increases following ex vivo cyclic loading.

Transected flexor tendons are typically treated by suture repair followed by rehabilitation that generates repetitive tendon loading. Recent results in an in vivo canine model indicate that during the first 10 days after injury and repair, there is an increase in the rigidity of the tendon repair site. Our objective was to determine whether or not ex vivo cyclic loading of repaired flexor tendons causes a similar increase in repair-site rigidity. We simulated 10 days of rehabilitation by applying 6000 loading cycles to repaired canine flexor tendons ex vivo at force levels generated during passive motion rehabilitation; we then evaluated their tensile mechanical properties. High-force (peak force, 17 N) cyclic loading increased repair-site rigidity by 100% and decreased repair-site strain by 50%, whereas low-force (5 N) loading did not change the properties of the repair site. This mechanical conditioning effect may explain, in part, the changes in tensile properties observed after only 10 days of healing in vivo. Mechanical conditioning of repaired flexor tendons by repetitive forces applied during rehabilitation may lead to increases in repair-site rigidity and decreases in strain, thereby altering the mechanical loading environment of tissues and cells at the repair site.

Animals↗
PubMed2002

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.

Animals↗
PubMed2002

Repair of flexor digitorum profundus tendon avulsions from bone: an ex vivo biomechanical analysis.

Avulsions or distal transections of the flexor digitorum profundus tendon are typically repaired by direct suture of the tendon stump to the distal phalanx. The optimal repair technique to withstand in vivo rehabilitation forces is unknown. Our objective was to determine the time-zero tensile mechanical properties of 4-strand tendon-bone repair site constructs performed with 3-0 and 4-0 sutures and with modified Kessler and modified Becker grasping techniques. We hypothesized that the 3-0 modified Becker grasping suture technique not described previously for the reattachment of tendon to bone would show improved biomechanical properties compared with the 4-0 or modified Kessler techniques. All modified Kessler repairs failed by suture pullout from the tendon, whereas all modified Becker repairs failed by rupture of the suture at the tendon-bone junction. Although the 3-0 modified Becker repair group showed greater ultimate force then the other groups (p <.01), tendon-bone gap observed did not differ markedly between Becker or Kessler groups. Neither suture caliber nor repair technique had a notable effect on strain at 20-N force, suggesting that early gap formation at the tendon-bone repair site may occur regardless of technique.

Animals↗
PubMed2002

Vascular anatomy of the human flexor digitorum profundus tendon insertion.

The vascular anatomy of the flexor digitorum profundus (FDP) tendon insertion is described by using a vascular injection and modified Spalteholtz tissue clearing protocol in 36 human cadaver digits. A consistent dense palmar and dorsal vascular supply to the tendon at its insertion into the distal phalanx was observed based on sources from both the distal phalanx and the vinculum brevis profundus. Multiple palmar-dorsal vascular interconnections were seen between these spatially distinct vascular networks, a finding not observed previously in studies of the vascular anatomy of tendon or ligament insertions. Additionally a well-defined dorsal zone of hypovascularity was identified subjacent to the volar plate of the distal interphalangeal joint, within 1 cm of the tendon insertion. Recognition of the vascular supply to the FDP insertion at the distal phalanx permits further evaluation of the vascular, histologic, and cellular events after FDP tendon avulsion and improves the understanding of the biologic response mechanisms involved in bone-tendon healing.

Fingers↗
PubMedDate not supplied

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 "cyclist's 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: Cyclist's palsy occurs at high rates in both experienced and inexperienced cylists. Steps may be taken to decrease the incidence of cyclist's palsy; these include wearing cycling gloves, ensuring proper bicycle fit, and frequently changing hand position.

Adult↗
PubMedDate not supplied

Recent progress in flexor tendon healing. The modulation of tendon healing with rehabilitation variables.

Until recently, attempts to optimize the postoperative regimen following intrasynovial flexor tendon repair had been essentially empirical, in that both the time and graduation of the exercise regimen have lacked clear conceptual guidelines. The magnitude of load applied in previous studies had not been clearly controlled, and similarly, the effects of increased repair site excursion and gap formation had not been evaluated in clinically relevant models. Recent experimental in vivo data on the application of force and excursion as independent variables by the authors and other investigators have helped to clarify the respective roles of these two variables. The goal of surgical treatment of intrasynovial flexor tendon lacerations is the achievement of a primary tendon repair of tensile strength sufficient to allow early controlled motion after surgery. The implementation of an appropriate postoperative rehabilitation protocol will, based on the experimental data discussed in this article, decrease the formation of intrasynovial adhesions, facilitate the restoration of the gliding surface, and stimulate the accrual of strength at the repair site.

Hand Injuries↗