A. Bobby Chhabra

Tendon: Biology, Biomechanics, Repair, Growth Factors, and Evolving Treatment Options

Surgical treatment of tendon ruptures and lacerations is currently the most common therapeutic modality. Tendon repair in the hand involves a slow repair process, which results in inferior repair tissue and often a failure to obtain full active range of motion. The initial stages of repair include the formation of functionally weak tissue that is not capable of supporting tensile forces that allow early active range of motion. Immobilization of the digit or limb will promote faster healing but inevitably results in the formation of adhesions between the tendon and tendon sheath, which leads to friction and reduced gliding. Loading during the healing phase is critical to avoid these adhesions but involves increased risk of rupture of the repaired tendon. Understanding the biology and organization of the native tendon and the process of morphogenesis of tendon tissue is necessary to improve current treatment modalities. Screening the genes expressed during tendon morphogenesis and determining the growth factors most crucial for tendon development will likely lead to treatment options that result in superior repair tissue and ultimately improved functional outcomes.

Peripheral nerve repair and reconstruction.

When possible, direct repair remains the current standard of care for the repair of peripheral nerve lacerations. In large nerve gaps, in which direct repair is not possible, grafting remains the most viable option. Nerve scaffolds include autologous conduits, artificial nonbioabsorbable conduits, and bioabsorbable conduits and are options for repair of digital nerve gaps that are <3 cm in length. Experimental studies suggest that the use of allografts may be an option for repairing larger sensory nerve gaps without associated donor-site morbidity.

Tissue engineering solutions for tendon repair.

Abstract Tendon injuries range from acute traumatic ruptures and lacerations to chronic overuse injuries, such as tendinosis. Even with improved nonsurgical, surgical, and rehabilitation techniques, outcomes following tendon repair are inconsistent. Primary repair remains the standard of care. However, repaired tendon tissue rarely achieves functionality equal to that of the preinjured state. Poor results have been linked to alterations in cellular organization within the tendon that occur at the time of injury and throughout the early stages of healing. Enhanced understanding of the biology of tendon healing is needed to improve management and outcomes. The use of growth factors and mesenchymal stem cells and the development of biocompatible scaffolds could result in enhanced tendon healing and regeneration. Recent advances in tendon bioengineering may lead to improved management following tendon injury.

Assessment of scaphoid viability with MRI: a reassessment of findings on unenhanced MR images.

OBJECTIVE The purpose of this article is to evaluate the accuracy of unenhanced T1-weighted MR images in predicting the vascular status of the proximal pole of the scaphoid in patients with chronic scaphoid fracture nonunions. MATERIALS AND METHODS A database search identified 29 patients with chronic scaphoid nonunions who underwent a preoperative MRI examination and intraoperative assessment of scaphoid viability from 2004 to 2009. T1-weighted MR images were evaluated by two musculoskeletal radiologists. If the proximal pole demonstrated diffusely decreased T1-weighted signal (less than or equal to that of skeletal muscle), the patient was placed in a moderate-to-high risk for avascular necrosis (AVN) category. Otherwise, the patient was placed in a viable-to-low risk for AVN category. Scaphoid viability or necrosis was diagnosed intraoperatively depending on whether punctate bleeding was present. After the patients were classified according to the T1-weighted appearance, the appearance on STIR images was recorded. RESULTS There were 29 patients (25 male) with a mean age of 21 years. When we compared the MRI results, using only the T1-weighted images, with the surgical findings, unenhanced MRI had a sensitivity, specificity, and accuracy of 55%, 94%, and 79%, respectively, for diagnosing AVN. Increased proximal pole STIR signal was noted with similar frequencies in patients with and without AVN. CONCLUSION T1-weighted unenhanced MRI is an acceptable alternative to delayed contrast-enhanced MRI in the preoperative assessment of the vascular status of the proximal pole of the scaphoid in patients with chronic fracture nonunions. STIR images were not beneficial in determining proximal pole viability.

Growth/differentiation factor-5 modulates the synthesis and expression of extracellular matrix and cell-adhesion-related molecules of rat Achilles tendon fibroblasts

This study was designed to examine the cellular and molecular response of tendon fibroblasts to growth/differentiation factor-5 (GDF-5). Rat Achilles tendon fibroblasts (ATFs) were treated in culture with varying concentrations of GDF-5 (0–1000 ng/ml) over varying periods of time (0–12 days). Cell proliferation, evaluated through use of a standard MTT colorimetric assay, confirmed that GDF-5 stimulates ATF proliferation in a concentration- and time-dependent fashion. Temporal and concentration analysis revealed that GDF-5 increases total DNA, glycosaminoglycan (GAG), and hydroxyproline (HYP) content. Ratios of HYP/DNA and GAG/DNA increased with increasing concentrations of GDF-5 (0–1000 ng/ml). Expression of the following 12 extracellular matrix (ECM) and cell-adhesion-related genes was assessed using real-time reverse transcriptase polymerase chain reaction (RT-PCR): collagen I (col I), collagen III (col III), matrix metalloproteinases (MMP)-3 and -13, aggrecan, tissue inhibitor of matrix metalloproteinase (TIMP)-2, syndecan-4, N-cadherin, tenascin-C, biglycan, versican, and decorin. RT-PCR data revealed an increase in the expression of col I, col III, MMP-3, MMP-13, TIMP-2, syndecan-4, N-cadherin, tenascin-C, and aggrecan genes by day 6. A statistically significant decrease in TIMP-2 and MMP-13 was observed on day 12. Decorin expression was depressed at all time points in cells treated with GDF-5. There was no significant change in biglycan expression in ATFs supplemented with GDF-5. These findings suggest that GDF-5 induces cellular proliferation and ECM synthesis as well as expression of ECM and cell-adhesion-related genes in ATFs. This study further defines the influence of GDF-5 on rat ATFs through its action on the expression of genes that are associated with tendon ECM.

Volar Plate Osteosynthesis of Distal Radius Fractures With Concurrent Prophylactic Carpal Tunnel Release Using a Hybrid Flexor Carpi Radialis Approach

PURPOSE To evaluate the safety and efficacy of a hybrid flexor carpi radialis (FCR) approach for volar plate osteosynthesis of displaced distal radius fractures with concurrent prophylactic carpal tunnel release (CTR) in patients without preoperative signs or symptoms of acute carpal tunnel syndrome secondary to the fracture. METHODS A total of 68 displaced distal radius fractures in 65 eligible adult patients (35 men, 30 women; mean age, 48.6 +/- 15.4 y) who had volar plate osteosynthesis and concomitant prophylactic CTR through a hybrid FCR approach by a single surgeon were included in this study. A systematic chart review and subsequent telephone questionnaire were performed to identify any postoperative median nerve dysfunction, recurrent motor or palmar cutaneous branch injury, tendon injury, or other complications directly related to the approach. RESULTS Reported symptoms consistent with late median nerve dysfunction were identified in 2 cases; however, no patients in this series required additional surgery for early or late median neuropathy. Furthermore, no cases of median nerve sensory or motor branch injury or tendon injury were identified. No other unforeseen complications specifically related to the approach were observed. CONCLUSIONS Volar plate osteosynthesis of distal radius fractures with a concurrent prophylactic CTR can be safely performed through the described hybrid FCR approach in patients without signs or symptoms of acute CTS. Routine release of the transverse carpal ligament with the hybrid FCR approach at the time of fracture fixation might reduce the incidence of postoperative median nerve dysfunction. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

Return to Football and Long-Term Clinical Outcomes After Thumb Ulnar Collateral Ligament Suture Anchor Repair in Collegiate Athletes

PURPOSE To evaluate return to play after complete thumb ulnar collateral ligament (UCL) injury treated with suture anchor repair for both skill position and non-skill position collegiate football athletes and report minimum 2-year clinical outcomes in this population. METHODS For this retrospective study, inclusion criteria were complete rupture of the thumb UCL and suture anchor repair in a collegiate football athlete performed by a single surgeon who used an identical technique for all patients. Data collection included chart review, determination of return to play, and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) outcomes. RESULTS A total of 18 collegiate football athletes were identified, all of whom were evaluated for follow-up by telephone, e-mail, or regular mail at an average 6-year follow-up. Nine were skill position players; the remaining 9 played in nonskill positions. All players returned to at least the same level of play. The average QuickDASH score for the entire cohort was 1 out of 100; QuickDASH work score, 0 out of 100; and sport score, 1 out of 100. Average time to surgery for skill position players was 12 days compared with 43 for non-skill position players. Average return to play for skill position players was 7 weeks postoperatively compared with 4 weeks for non-skill position players. There was no difference in average QuickDASH overall scores or subgroup scores between cohorts. CONCLUSIONS Collegiate football athletes treated for thumb UCL injuries with suture anchor repair had quick return to play, reliable return to the same level of activity, and excellent long-term clinical outcomes. Skill position players had surgery sooner after injury and returned to play later than non-skill position players, with no differences in final level of play or clinical outcomes. Management of thumb UCL injuries in collegiate football athletes can be safely and effectively tailored according to the demands of the players football position. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

Single-Incision Extensile Volar Approach to the Distal Radius and Concurrent Carpal Tunnel Release: Cadaveric Study

PURPOSE To determine whether a single-incision extensile approach to the distal radius used for open reduction internal fixation and a concomitant radial sided carpal tunnel (CT) release safely and effectively decompresses the carpal tunnel. METHODS Five pairs of cadaveric forearms were mounted to a tabletop with a cable pulley system attached to the long finger. Each paired specimen was randomized to volar plating via either the flexor carpi radialis approach (control group) or the extensile volar exposure (combined flexor carpi radialis and radial-sided carpal tunnel release). Before and after the respective exposure and plating, increased CT pressures were created with 2.27, 4.54, and 6.81 kg of distraction. We used a paired t-test to compare the change in CT pressure at each level of distraction before and after intervention for the 2 groups, with significance set at p </= .05. A dissection of each exposure was performed with attention given to the radial aspect of the transverse carpal ligament (TCL) and any possible iatrogenic injuries. RESULTS Carpal tunnel pressure increased with increasing distraction. We noted a statistically significant reduction in CT pressure after the extensile exposure and plating with 4.54 (p = .023) and 6.81 (p < .001) kg of distraction, respectively. No significant reduction in mean CT pressure for the control group specimens occurred at any level of distraction force. The average length of the radial TCL was 22 mm (range, 18-31 mm); the average distance between the recurrent motor branch and distal TCL was 11 mm (range, 8-15 mm). No iatrogenic tendon or nerve injury occurred with the extensile volar exposure. CONCLUSIONS Carpal tunnel pressure is safely reduced and the distal radius is adequately exposed for fixation with the extensile volar approach.

Treatment of chronic nonunions of the humerus with free vascularized fibula transfer: a report of thirteen cases.

Chronic nonunions of the humerus remain a challenging problem. We reviewed 13 cases of chronic nonunion of the humerus resulting from trauma or osteomyelitis treated with vascularized fibula transfer after failure of conventional treatment. Patient averages were 35 years of age, follow-up of 19 months, and 4.2 prior operations. Healing was obtained in 12 of 13 (92%) patients with an average healing time of 18 weeks and graft length of 12.5 cm. In total, 11 of 12 (91%) patients who united had good to excellent range of motion of their shoulder and elbow. There were eight complications in 7 of 13 patients (54%). Two patients developed fractures of the graft, and three had superficial infections at the harvest site requiring operative debridement. Two patients had median neurapraxia that resolved by 4 months. Two patients complained of intermittent pain at the donor site. No significant correlations were found between time to heal and other covariates.

Magnetic resonance imaging of the hand and wrist: techniques and spectrum of disease: AAOS exhibit selection.

Magnetic resonance imaging (MRI) is an excellent imaging modality for the evaluation of pathologic processes of the hand and wrist. MRI of the hand and wrist provides high-resolution imaging of osseous structures and soft-tissue structures (including ligaments, tendons, nerves, and muscles) through the use of multiple imaging techniques and pulse sequences. This article updates orthopaedic surgeons on current MRI techniques and illustrates the spectrum of hand and wrist disease detectable by MRI. We searched PubMed with use of the keywords “MRI” plus “hand” or “wrist” for studies less than five years old evaluating MRI techniques. On the basis of a review of the recently published literature and the authors’ experience, we define and describe the applications of the following: (1) conventional, non-gadolinium-enhanced MRI, (2) gadolinium-enhanced MRI, and (3) MR arthrography. We also describe the classic MRI appearance of lesions commonly evaluated by MRI, including occult fracture, triangular fibrocartilage complex injury, interosseous ligament injury, extrinsic carpal ligament injury, thumb ulnar collateral ligament injury, traumatic tendon injury, finger pulley injury, ulnar impaction syndrome, tendinopathy, Kienbock disease, posttraumatic scaphoid osteonecrosis, infection, inflammatory arthropathy, compression neuropathy, and various soft-tissue masses. The incorporation of dedicated surface coils and higher-strength magnets has improved the quality of magnetic resonance imaging (MRI) scanners substantially over the last decade. By manipulating the scanning parameters when performing an MRI examination, contrast differences between tissues can be emphasized on the basis of inherent tissue properties known as T1 and T2. T1-weighted images are generally regarded as best for illustrating anatomic detail. T2-weighted sequences highlight alterations in water content, which are characteristic of most pathologic conditions. Short tau inversion recovery (STIR) and fat-suppressed T2-weighted images accentuate fluid and edema and are the most sensitive for detecting pathologic changes in both bone and soft tissue. The intravenous administration of a gadolinium-based contrast agent …