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Biomedical subjects

Richard H Gelberman

Publications and source records attributed to Richard H Gelberman.

At least 19 recordsLinked to original sources
PubMed2007

Alendronate prevents bone loss and improves tendon-to-bone repair strength in a canine model.

Previously we showed a loss of bone and a concomitant decrease in mechanical properties in the first 21 days after flexor tendon insertion site injury and repair in a canine model. The goal of this short-term study was to suppress bone loss after insertion site repair using alendronate in an attempt to prevent the reduction in biomechanical properties. Flexor tendons of the second and fifth digits of the right forelimbs of canines were injured and repaired. Dogs received a daily oral dose of alendronate (2 mg/kg). One digit in each dog also received a local dose of alendronate in the bone tunnel at the time of surgery. The repair was evaluated for bone mineral density (BMD) and biomechanical properties and compared to data from a previous study in which no alendronate was used. Alendronate was effective in protecting the distal phalanx from resorption during tendon-to-bone healing (BMD was 94 and 104% of control for systemic alendronate and for systemic plus local alendronate, respectively). Alendronate treatment prevented much of the decrease in ultimate load that occurs in the first 21 days. Without treatment, ultimate load was 42% of control. With systemic alendronate treatment and systemic plus local alendronate treatment, ultimate load was 78 and 69% of control, respectively. Failure mode was significantly different when comparing alendronate treatment to repair alone. A lower incidence of suture pull through was found in alendronate treated dogs, suggesting less tendon degeneration. Ultimate load can be improved in association with preventing the bone loss that normally occurs during the early period following tendon-to-bone repair. These initial short-term data demonstrate the potential for a clinical treatment that could enhance tendon-to-bone healing.

Alendronate↗
PubMed2006

Early healing of flexor tendon insertion site injuries: Tunnel repair is mechanically and histologically inferior to surface repair in a canine model.

Orthopedic injuries often require surgical reattachment of tendon to bone. Tendon ends can be sutured to bone by direct apposition to the bone surface or by placement within a bone tunnel. Our objective was to compare early healing of a traditional surface versus a novel tunnel method for repair of the flexor digitorum profundus (FDP) tendon insertion site in a canine model. A total of 70 tendon-bone specimens were analyzed 0, 5, 10 or 21 days after injury and repair, using tensile and range of motion mechanical testing, histology and densitometry. Ultimate force (a measure of repair strength) did not differ between surface and tunnel repairs at day 0. Both repair types had reduced strength at 10 and 21 days compared to 0 days, indicative of deterioration of suture grasping strength (tendon softening). At 21 days, tendons repaired in a bone tunnel had 38% lower ultimate force compared to surface repairs (p = 0.017). Histological findings were comparable between repair groups at 5 and 10 days but differed at 21 days, when we saw evidence of maturation of the tendon-bone interface in the surface repairs compared to an immature fibrous interface with no evidence of tendon-bone integration in the tunnel repairs. After accounting for bone removed by the tunnel, no difference in bone mineral density or trabecular bone volume existed between surface and tunnel repairs. If the results of our animal study extend to healing of the human FDP insertion, they indicate that FDP tendons should be reattached to the distal phalanx by suture to the cortical surface rather than suture in a bone tunnel.

Animals↗
PubMed2006

Treatment of distal radius fractures with a low-profile dorsal plating system: an outcomes assessment.

PURPOSE: To evaluate objective functional and radiographic outcomes after internal fixation of acute, displaced, and unstable fractures of the distal aspect of the radius in adults by using a low-profile dorsal plating system. Our hypothesis was that the low-profile dorsal plating system would allow for a reduction of extensor tendon irritation and pain and provide stable osseous fixation. METHODS: Sixty consecutive unstable fractures in 59 patients were treated by open reduction internal fixation using a low-profile dorsal plating system. There were 29 type A, 14 type B, and 8 type C fractures (AO classification system). Fifty patients with 51 fractures returned for outcomes assessment by physical examination, plain radiographs, and completion of a validated musculoskeletal function assessment questionnaire. The minimum follow-up period was 1 year; the mean follow-up period was 24 months. Clinical evaluation was performed and plain radiographs were assessed for maintenance of immediate postoperative reduction and implant position. Objective functional assessment was obtained through the Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: Outcomes analysis showed no cases of extensor tendon irritation or rupture. Hardware removal was performed in 1 patient but no extensor tendon irritation or rupture was evidenced. The mean Disabilities of the Arm, Shoulder, and Hand score was 11.9; implant-related discomfort was minimal. All patients had an excellent (31 patients) or good (19 patients) result according to the scoring system of Gartland and Werley. The mean active range of motion was greater than 80% of that of the contralateral wrist in flexion/extension, pronation/supination, and ulnar/radial deviation. Extensor tendon function was unimpaired in all patients. Grip and pinch strength averaged 90% and 94% of the contralateral sides, respectively. Radiographic evaluation showed no change in fracture reduction or implant position. CONCLUSIONS: The treatment of distal radius fractures with a low-profile stainless steel dorsal plating system is a safe and effective method that provides stable internal fixation and allows for full extensor tendon glide and full metacarpophalangeal joint motion. Objective outcome testing showed uniformly good to excellent recovery of wrist and hand function in all patients. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic, Level IV.

Adult↗
PubMed2006

The alchemy of tendon repair: a primer for the (S)mad scientist.

During vertebrate development, mesenchymal progenitors capable of forming bone, cartilage, muscle, fat, or tendon arise from either neural crest or somitic mesoderm. Transcriptional programs that specify mesenchymal cell fates are initiated and modified by paracrine cues provided by TGF-beta superfamily members and mediated in part via the regulated assembly of Smad-containing multiprotein transcription factor complexes. In this issue of the JCI, Hoffmann and colleagues have identified that Smad8 activation drives tendon formation from C3H10T1/2 cells, a murine cell line that recapitulates many features of normal multipotent mesenchymal cells (see the related article beginning on page 940). Cells programmed to the tenocyte cell fate in vitro formed tenogenic grafts in vivo. These results add to the accumulating evidence that proliferating, multipotent mesenchymal progenitor cells can be programmed to yield multiple cell types--e.g., osteoblasts, myocytes, chondrocytes, and tenocytes--that may be useful in cell-based therapeutic approaches to musculoskeletal diseases.

Bone Development↗
PubMed2005

Flexor digitorum profundus tendon to bone tunnel repair: a vascularization and histologic study in canines.

PURPOSE: Recent in vivo canine studies have shown incomplete restoration of the flexor digitorum profundus (FDP) insertion site after transection and repair to the cortical surface of the distal phalanx. Previous biomechanical analyses of tendon to bone surface repair have suggested that repair site gap formation of greater than 3 mm occurs frequently under physiologic loads. A recent ex vivo investigation into a novel repair of the FDP tendon into a bone tunnel in the distal phalanx showed improved tensile properties with a decrease in repair site gap formation. Time-zero data, however, do not always accurately reflect in vivo responses. The repair response of the FDP tendon when placed in an osseous compartment is not known. The purpose of this study was to analyze the histologic and vascular anatomic properties of the FDP insertion site after transection and repair in a bone tunnel within the distal phalanx. METHODS: Twenty-six FDP tendon to bone repairs were performed in 13 adult mongrel dogs after insertion site transection. The tendons were repaired in a bone tunnel in the distal phalanx. Vascular analysis of the tendon and repair site was performed by using a modified Spalteholtz technique and routine hematoxylin-eosin staining was used to assess histologic properties of the repair. RESULTS: In normal specimens the vascular analysis showed that there was a distal network of vessels extending 1- to 2-cm proximal to the FDP insertion site. At 10 days after repair the distal tendon segment tendon remained avascular. By 21 days after repair there was proximal migration of an unorganized reticular network of tendon surface vessels with sparse intratendinous communications. At 6 weeks after repair the structure of the distal tendon vascular network resembled that of normals. The vascular response of the tendon within the bone tunnel followed a similar time frame. Histologic analysis showed an inflammatory reaction in the bone tunnel leading to a progressive degradation of that portion of the FDP tendon that resided in the tunnel. Tendon necrosis was not seen. CONCLUSIONS: The FDP tendon, after insertion site transection and repair in a bone tunnel, undergoes a process of neovascularization and revascularization over a period of 6 weeks. There is a progressive loss of tendon parenchyma within the bone tunnel and the suture tracks appeared to serve as conduits for the ingrowth of inflammatory tissue. Restoration of the normal 4-zone tendon-bone interface was not seen. Although ex vivo biomechanical assessment of tendon repair in a bone tunnel appears promising, the repair response in vivo may not be favorable for tendon to bone healing. The progressive tendon degeneration that was observed here may have detrimental effects on repair site tensile properties, increasing the potential for early failure.

Animals↗
PubMed2005

Nerve decompression for complex regional pain syndrome type II following upper extremity surgery.

PURPOSE: To evaluate the results of nerve decompression for the symptoms of complex regional pain syndrome that developed after upper-extremity surgery. METHODS: Eight patients (5 men, 3 women) developed worsening severe pain, swelling, and loss of range of motion after an upper-extremity surgery. The diagnosis of complex regional pain syndrome was made at an average of 6 weeks (range, 1-10 weeks) after the surgical procedure. A clinical diagnosis of either median or combined median and ulnar nerve compression at the wrist was confirmed in all patients with electrophysiologic testing. Nerve decompression was performed at a mean of 13 weeks after the procedure. Subjective (Disabilities of the Arm, Shoulder, and Hand questionnaire; visual analog pain scale) and objective (forearm, wrist, and finger range of motion; grip strength) data from before and after nerve decompression were reviewed. RESULTS: The average score on the Disabilities of the Arm, Shoulder, and Hand questionnaire decreased from 71 to 30 (p < .05). The mean visual analog pain score decreased from 7.5 to 1.8. (p < .05) There was immediate and near-complete resolution of all somatic complaints including hypersensitivity to touch, hyperhydrosis, swelling, and cold sensitivity. Range of motion and grip strength improved. CONCLUSIONS: Traditionally surgical treatment has been avoided in patients with complex regional pain syndrome; however, in the setting of clinical and electrophysiologic evidence of nerve compression surgical intervention may hasten recovery in these patients.

Aged↗
PubMed2005

Zone I flexor digitorum profundus repair: an ex vivo biomechanical analysis of tendon to bone repair in cadavera.

PURPOSE: Biomechanical studies of standard flexor digitorum profundus (FDP) tendon to bone repairs show ultimate strengths greater than the applied loads of early motion rehabilitation protocols. Strain data, however, indicate the potential for significant repair site gapping under these physiologic loads. Gaps in excess of 3 mm have been shown to prevent the time accrual of strength in midsubstance tendon repairs and may prevent the restoration of the normal architecture of the tendon-bone interface. Improving the time-zero tensile properties of FDP insertion site repairs may help obviate these issues and improve clinical outcomes. The purpose of this study was to evaluate the ex vivo biomechanical properties of 2 new repair techniques in comparison with the standard FDP tendon to distal phalanx cortical surface repair. METHODS: Thirty human cadaver FDP tendons were released from their insertion sites by sharp dissection and repaired to bone using 1 of 3 repair techniques. Load to failure testing was performed with a servohydraulic materials-testing system (model 8500R; Instron, Canton, MA) analyzing ultimate force, strain at 20 N, rigidity, force to 2-mm gap formation, and displacement at failure. RESULTS: The results of the failure tests indicate that repairs performed with the addition of a peripheral suture had a greater ultimate force, had increased resistance to gap formation, and had increased rigidity and decreased strain at 20 N compared with the tunnel-only and volar cortical surface to the distal phalanx repairs. Although there were no statistically significant differences in ultimate force or rigidity between the tunnel-only and volar cortical surface repairs, the tunnel-only repairs showed lower strain values and increased values for resistance to 2-mm gap formation when compared with the volar cortical surface repairs. There were no differences among any of the repair groups with regard to the magnitude of tendon displacement from the repair site at failure. CONCLUSIONS: The addition of a peripheral suture to the FDP tendon to bone tunnel repair construct improves the time-zero tensile properties as evidenced by statistically significant increases in ultimate force, rigidity, and resistance to gap formations of 2 mm. In comparison with a volar cortical surface repair, the bone tunnel-only repairs were effective at decreasing the amount of repair site strain during applied loads of 20 N. If these improved time-zero tensile properties persist during the early stages of healing, they may help decrease the incidence of repair-site gap formation associated with the forces of early motion rehabilitation protocols.

Aged↗
PubMed2005

Effect of several growth factors on canine flexor tendon fibroblast proliferation and collagen synthesis in vitro.

PURPOSE: Growth factor delivery may be useful to accelerate the rate of tendon healing. Before in vivo use, however, the effects of growth factors on tendon cells need to be well characterized. The purpose of this study was to evaluate the effects of 4 growth factors on intrasynovial tendon fibroblast proliferation and collagen production in vitro. Our first hypothesis was that platelet-derived growth factor BB (PDGF-BB) and basic fibroblast growth factor (bFGF) would promote cell proliferation and collagen production. Our second hypothesis was that there would be a positive effect from the combination of PDGF-BB and bFGF. METHODS: The growth factors PDGF-BB, bFGF, vascular endothelial growth factor (VEGF), and bone morphogenetic protein 2 (BMP-2) were evaluated in vitro with canine flexor tendon fibroblasts. The effects of single factors (PDGF-BB, bFGF, VEGF, or BMP-2) or a combination of factors (PDGF-BB and bFGF) on cell proliferation (ie, thymidine incorporation) and collagen production (ie, proline incorporation) were evaluated. RESULTS: The results supported our hypotheses. Cell proliferation increased significantly with PDGF-BB and bFGF. Collagen production also increased significantly with PDGF-BB and bFGF. Cell proliferation and collagen production were unchanged with VEGF and BMP-2. A dose-response effect was seen for PDGF-BB combined with bFGF. The combination of PDGF-BB and bFGF led to an increase in cell proliferation but no change in collagen production compared with each factor alone. CONCLUSIONS: The growth factors PDGF-BB and bFGF significantly increased flexor tendon fibroblast proliferation and matrix synthesis when applied singly. Administration of PDGF-BB and bFGF combined led to increased proliferation to single factors.

Animals↗
PubMed2004

Anatomic tilt x-rays of the distal radius: an ex vivo analysis of surgical fixation.

PURPOSE: To compare anatomic tilt radiographs with standard posteroanterior (PA) and lateral radiographs for their efficacy in detecting screw penetration of the distal radius articular surface. METHODS: Twenty-four cadaveric human forearm specimens had fixation with a dorsal distal radius plate and screws. Three groups were evaluated: (1) no articular surface screw penetration, (2) radial-sided articular screw penetration, and (3) ulnar-sided articular screw penetration. Standard PA and lateral views and anatomic tilt PA and lateral views were taken of each specimen. Three observers reviewed both individual (PA or lateral) and paired (PA and lateral) radiographs. These radiographs were evaluated based on whether or not articular penetration had occurred. A number between 1 and 5 was assigned to represent the degree of certainty of their assessment. The accuracy of the observers was calculated to determine if screw penetration of the articular surface had occurred and, if so, which screw had penetrated the joint. The sensitivity and specificity of each view, interobserver reliability, and the reviewers' confidence in evaluating presence or absence of screw penetration were calculated. RESULTS: The use of anatomic tilt lateral views significantly improved the overall accuracy, (0.93 vs 0.64), sensitivity (0.98 vs 0.77), and specificity (0.83 vs 0.38) of the detection of articular screw penetration when compared with standard lateral views. PA and lateral anatomic tilt views, when viewed together, significantly improved (p <.001) the accuracy of each observer's determination of the position of the penetrated screw (0.90 vs 0.67). In addition, anatomic tilt views significantly improved the confidence of the reviewers in their more accurate observations (4.7 vs 3.3, p <.05). CONCLUSIONS: Anatomic tilt PA and lateral radiographs of the distal radius are an accurate and clinically useful tool for the evaluation of both presence and location of screw penetration of the articular surface after dorsal plating.

Bone Plates↗
PubMed2004

Ligament reconstruction with trapezium retention arthroplasty for carpometacarpal arthritis.

PURPOSE: The purpose of this study is to provide a qualitative and quantitative assessment of results in a consecutive series of patients with carpometacarpal arthritis using a trapezium-retaining interposition arthroplasty. METHODS: Between 1999 and 2002, 16 patients with basal joint arthritis were treated with a trapezium-retaining interposition arthroplasty. Fourteen of these patients were evaluated at a mean follow-up time of 20 months (minimum, 12 months) and were compared based on clinical outcome, presurgical and postsurgical x-ray evaluation, and range of motion, grip-strength, and pinch-strength values. RESULTS: Average trapezial height values as quantified by the trapezial space to proximal phalanx ratio were very similar before and after surgery. Average grip-strength values improved significantly. Although average pinch-strength and average range of motion values improved neither of these comparison values were significant. Thirteen of the 14 patients (93%) were satisfied with their results as quantified by postsurgical Disabilities of the Arm, Shoulder, and Hand questionnaires. CONCLUSIONS: Ligament reconstruction with trapezium retention arthroplasty of the basal joint not only successfully maintains trapezial height but also yields patient satisfaction rates comparable to those achieved with other forms of basal joint arthroplasty.

Adult↗
PubMed2004

Vascularity and osteonecrosis of the wrist.

This article outlines the vascular anatomy of the carpus, describing the extraosseous and intraosseus vascular systems and emphasizing the carpal bones at risk for osteonecrosis. Separate discussions of etiology, diagnosis, and treatment of osteonecrosis of the commonly involved carpal bones are included.

Arthroplasty↗
PubMed2004

Tendon injury response: assessment of biomechanical properties, tissue morphology and viability following flexor digitorum profundus tendon transection.

Insertion site injuries of the flexor digitorum profundus (FDP) tendon often present for delayed treatment. Apart from gross observations made at the time of surgery, the changes that occur in the flexor tendon stump during the interval from injury to repair are unknown. These changes may include tendon softening and loss of viability, which may contribute to the poor outcomes observed clinically and experimentally. Thirty-eight FDP tendons from 23 adult dogs were transected sharply from their insertions on the distal phalanges and were not repaired. Dogs were allowed full weight bearing and were euthanized 7 or 21 days after injury. Biomechanical testing indicated that the resistance of injured tendons to pullout of a Kessler-type suture was not different from control tendons at 7 days and was increased at 21 days by 25% (p<0.05). Morphologically, at 7 and 21 days the cut surface had a smooth appearance and the end of the injured tendon was increased in thickness by 30% and 50%, respectively (p<0.05). Histologically, we observed increased cellularity and dramatic fibroblast proliferation within the injured tendon stump; there was no evidence of decreased cell viability. We conclude that during the interval from 0 to 21 days after FDP insertion-site injury, tendons cells are viable, proliferative and synthesizing new matrix. This leads to increased tendon size and enhanced resistance to suture pullout. These findings offer a scientific rationale supporting the clinical practice of surgical re-attachment within the first 3 weeks after injury.

Animals↗
PubMed2003

Bone loss following tendon laceration, repair and passive mobilization.

Little is known about the localized changes in bone mass that occur following tendon or ligament injury. Interruption of normal load transfer at the insertion site will presumably lead to a localized loss of bone, although few data exist to support this claim. To test this hypothesis, we transected the canine flexor digitorum profundus (FDP) tendon from its insertion, and either repaired it using a trans-osseous suture technique or left it unrepaired (laceration only). Post-operatively, forelimbs in the repair group were cast immobilized except for 10 min of daily passive mobilization rehabilitation, whereas in the laceration only group dogs were allowed full weight bearing. At 5-42 days post-injury, we assessed bone mineral density (BMD) using pQCT and osteoclast surface by histomorphometry. We measured significant bone loss in the distal phalanx after combined FDP tendon laceration, repair, and post-operative passive mobilization, with BMD decreases of 20%, 40%, and 41% at 10, 21, and 42 days (p<0.01). Moreover, we observed that passive mobilization and tendon laceration each contributed independently to the observed bone loss. At 42 days, BMD was reduced by 21% in bones that were not injured but were subjected to the post-operative passive mobilization protocol, while BMD was reduced by 28% in bones subjected to tendon laceration and full weight bearing (p<0.01). In both the passive mobilization and laceration specimens, we counted significantly increased osteoclasts after only 7-10 days, and these increases persisted through 42 days (p<0.05). We conclude that rapid and sustained bone resorption leads to significant bone loss in the 6-week period following flexor tendon injury and repair. This bone loss may impact healing by impeding the restoration of a strong tendon-bone interface.

Animals↗
PubMed2003

Neovascularization of the flexor digitorum profundus tendon after avulsion injury: an in vivo canine study.

PURPOSE: The changes in matrix material properties and intrinsic vascularization that have been noted in intrasynovial tendon stumps after avulsion injury may be of considerable clinical relevance with regard to the results of surgical repair. Our objective was to determine both the time course and the source of neovascularization of the tendon stump in an in vivo canine model of flexor digitorum profundus (FDP) avulsion after a clinically relevant delay in diagnosis. METHOD: The FDP tendon was released from bone directly by sharp dissection and the vinculum brevis profundus was lacerated, simulating an avulsion injury with interruption of the vascular supply to the tendon stump. After death at 7 and 21 days, tendon vascularity was evaluated with India ink injection and clearing using a modified Spalteholtz technique. RESULTS: All 7-day specimens showed an absence of vascularity compared with the controls. In all 21-day specimens a direct vascular supply originated from local fibrovascular adhesions contacted the stump on its surface and blood vessels penetrated the tendon stump circumferentially. Progressive vascularization of the avulsed tendon stump occurred between 7 and 21 days after injury, originating from fibrovascular adhesions to the surrounding synovial sheath. CONCLUSIONS: Whereas previous studies of intrasynovial flexor tendon laceration and repair have shown a progressive proximal to distal neovascularization of the FDP during the early postoperative period, longitudinal proximal to distal growth from the proximal blood supply of the FDP was not observed toward the unrepaired tendon stump.

Animals↗
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↗
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↗