Comparative Effectiveness Systematic Review and Meta-analysis of Peripheral Nerve Repair Using Direct Repair and Connector-assisted Repair.

Background: This clinical literature systematic review and meta-analysis were performed to assess differences in outcomes between nerves repaired with direct repair (DR) and connector-assisted repair (CAR). Methods: A systematic literature review for DR and CAR was performed. Studies from 1980 through August 2023 were included if DR or CAR repairs were performed in upper extremities with nerve gaps less than 5 mm and reported sensory Medical Research Council Classification (MRCC) outcomes or equivalent. Comparative analyses were planned for meaningful recovery (MR) rate (at both S3 and S3+ or better), postsurgical neuroma, cold intolerance, altered sensation, pain, and revision rate. Results: There were significant differences in MR rates for CAR and DR. At the MRCC S3 threshold, 96.1% of CAR and 81.3% of DR achieved MR (P < 0.0001). At the MRCC S3+ threshold, 87.1% of CAR and 54.2% of DR achieved this higher threshold of MR (P < 0.0001). There were no differences in neuroma rate or pain scores in our dataset. Altered sensation (dysesthesia, paresthesia, hyperesthesia, or hypersensitivity) was not discussed in any CAR studies, so no analysis could be performed. The revision rate for both procedures was 0%. The proportion of patients with cold intolerance was 46.2% in the DR studies, which was significantly higher than the 10.7% of patients in the CAR group. Conclusions: Significantly more patients achieved sensory MR and fewer had cold intolerance when the CAR technique, instead of the DR technique, was performed to repair peripheral nerve injuries.

The Effect of Thumb Metacarpophalangeal Hyperextension on Thumb Axial Load and Lateral Pinch Force in a Cadaver Model of Thumb Trapeziectomy and Flexor Carpi Radialis Suspensionplasty.

PURPOSE: The purpose of our study was to investigate, in a cadaver model, the effect of increasing thumb metacarpophalangeal (MCP) joint hyperextension on thumb axial load and key pinch force after thumb trapeziectomy and flexor carpi radialis suspensionplasty. We developed a cadaveric model to test whether thumb MCP joint hyperextension after trapeziectomy would have a negative effect on key pinch force and increase loads across a reconstructed thumb carpometacarpal (CMC) joint. METHODS: We created a cadaveric biomechanical model that varied thumb MCP joint hyperextension while measuring thumb CMC axial and key pinch force under standardized loads. Direct observations were made of how key pinch and axial thumb CMC force change with increasing thumb MCP joint hyperextension. We measured the thumb key pinch force and axial thumb CMC joint load with the thumb MCP joint in 0°, 10°, 20°, 30°, 40°, 50°, and 60° of hyperextension. RESULTS: There was a 0.88 N (2.4%) increase in axial force across the thumb CMC per every 10° of increasing thumb MCP joint hyperextension. We found a 0.53 N (4.4%) reduction in key pinch force for every 10° of increasing thumb MCP joint hyperextension. Therefore, at 60° of thumb MCP joint hyperextension, the axial force across the thumb CMC increased by 5.3 N (14.6%) and the key pinch force was weakened by 3.2 N (26.6%). CONCLUSIONS: With progressive thumb MCP joint hyperextension after thumb CMC arthroplasty, we found a decrease in key pinch force and an increase in axial thumb CMC joint force. The decrease in key pinch force was larger than the relatively small increase in thumb CMC force. CLINICAL RELEVANCE: This study helps elucidate the biomechanics of the thumb CMC joint after resection arthroplasty with thumb MCP joint hyperextension and helps understand the interplay between these 2 conditions.

A Cadaveric Comparison of Approaches for Exposure of the Volar Distal Radius: Is There a Utilitarian Approach?

BACKGROUND: It remains unclear whether exposure for planned fixation of distal radius fractrues is superior with any given approach, and whether a single utilitarian approach exists that permits reliable complete exposure of the volar distal radius. METHODS: A cadaveric study was performed using 10 matched specimens. Group 1 consisted of 3 radially based approaches (standard flexor carpi radialis [FCR], standard FCR with radial retraction of FCR and flexor pollicis longus [FPL] tendons, extended FCR). Group 2 consisted of 2 ulnarly based approaches (volar ulnar, extended carpal tunnel). The primary outcome was total width of exposed distal radius at the watershed line. Mann-Whitney U and Wilcoxon rank testing was used to identify differences. RESULTS: The standard FCR approach exposed 29 mm (90%), leaving on average 3 mm (10%) of the ulnar corner unexposed. Retracting the FCR and FPL tendons radially allows for an extra 1 mm of volar ulnar corner exposure. Finally, converting to an extended FCR approach provided 100% exposure in all specimens. The volar ulnar exposure however provided exposure to only 9 mm (37%), leaving 20 mm (62.5%) left unexposed radially. The extended carpal tunnel provided exposure to 21 mm (65%), leaving 11 mm (35%) radially unexposed. Differences between each group were statistically significant (P < .05). CONCLUSIONS: The extended FCR approach exposed 100% of the volar distal radius in our study and may serve as a utilitarian volar surgical approach for exposure and fixation of distal radius fractures. Additional knowledge of the limitations of alternative approaches can be helpful in surgical planning.

The Effect of Intraoperative Glove Choice on Carpal Tunnel Pressure.

Introduction The aim of this study was to quantify the effect of surgical gown and glove wear on carpal tunnel pressure. The authors hypothesized that gowning and gloving is associated with an increase in carpal tunnel pressure in cadaveric specimens wearing appropriately sized gloves. Furthermore, they hypothesized that increased glove thickness, double gloving, and smaller-than-appropriately sized gloves would all serve to increase carpal tunnel pressure. Materials and Methods Baseline carpal tunnel pressure measurements were obtained in 11 cadaveric specimens. Each specimen was subsequently gowned and gloved. Carpal tunnel pressures were obtained for each specimen fitted with four different types of gloves in four scenarios: (1) appropriately sized gloves, (2) one full-size smaller, (3) one full-size larger, and (4) double gloved. Results Mean carpal tunnel baseline value was 3.5 mm Hg. Appropriately sized single-glove wear more than doubled baseline carpal tunnel pressure. Double gloving and smaller-than-appropriately sized glove wear more than tripled baseline values. Among the single-glove subgroup, the thickest gloves (ortho) were associated with the highest increase in pressure from baseline values. Conclusion Glove selection can have repercussions related to carpal tunnel pressure. Susceptible surgeons should consider these factors when making decisions regarding intraoperative glove wear.

A pediatric medial epicondyle fracture study using fresh frozen adult cadavers comparing fracture displacement and loss of terminal elbow extension.

Medial epicondyle fractures are the 3rd most common pediatric elbow fractures. Regardless of treatment method, some degree of elbow motion loss has been reported. The purpose of our study was to determine the relationship between the amount of anterior fracture displacement and loss of elbow passive extension in an adult cadaveric medial epicondyle fracture model. Fifteen fresh frozen adult cadavers were procured to create fracture models at scenarios of 2, 5, 10 mm, and maximum displacement. Terminal elbow extension was recorded for each cadaveric model at each fracture scenario. A linear mixed model regression analysis was used to test the association between fracture displacement and loss of terminal elbow passive extension. At 2 mm of displacement, the average loss of terminal extension was 3.89°; at 5 mm, it was 7°; at 10 mm, it was 10.7°; at maximum displacement (~15 mm), it was 17°. A statistically significant positive linear association between fracture displacement and loss of terminal elbow extension was observed (5 mm of displacement = loss of ~4.7°). In our fracture model, when the medial epicondyle displaced anteriorly, we noticed a change in the tension of the medial collateral ligaments which lead to a decrease in terminal elbow extension. However, this only contributed partially to the loss of motion observed clinically in the literature. Even though our findings did not support the recommendation of surgical intervention to prevent loss of elbow motion in medial epicondyle fractures, we still encourage physicians to consider the consequence of displacement and its potential influence of elbow range of motion.

A Pediatric Medial Epicondyle Fracture Cadaveric Study Comparing Standard AP Radiographic View With the Distal Humerus Axial View.

BACKGROUND: Controversy exists with regard to the amount of fracture displacement that warrants surgical fixation of medial epicondyle fractures. Inaccurate determination of degree of displacement on plain radiographs may account for the disputed management. Recently, a novel distal humerus axial radiograph technique has been developed to improve the accuracy of radiographs. The purposes of the study are 2-fold; to identify the anatomic orientation of the medial elbow epicondyle physis in children and to compare the accuracy of determining fracture displacement between axial radiographs and standard anterior-posterior (AP) radiographs in a cadaveric medial epicondyle fracture model. METHODS: Twelve pediatric elbow computed tomographic scans and 19 pediatric elbow magnetic resonance imaging scans were analyzed for the orientation of the medial elbow physis. After determining the correct orientation, 15 adult cadaveric medial epicondyle fracture models were created at displacements of 2, 5, 10 mm, and maximum displacement with elbow at 90 degrees of flexion. A linear mixed model regression analysis was used to compare displacement based on the axial versus the AP radiographic methods. RESULTS: The medial epicondyle physis was found to be a posterior structure angled distally at ~36 degrees (range, 10.7 to 49.6) and angled posteriorly at 45 degrees (range, 32.2 to 59). The AP radiograph significantly underestimated displacement relative to the axial radiograph at 5 mm [mean difference, -1.6; 95% confidence interval (CI), -2.9 to -0.3], at 10 mm (mean difference, -4.5; 95% CI, -5.8 to -3.2 mm), and at maximal displacement (mean, 15 mm; range, 13 to 20 mm) (mean difference, -7.1; 95% CI, -8.3 to -5.8). CONCLUSIONS: The medial epicondyle physis of the distal humerus is a posterior structure angled distally and posteriorly. When displacement was >5 mm, the distal humerus axial radiograph technique was significantly more accurate than the AP radiograph technique at determining actual fracture displacement in our adult cadaveric fracture models. Therefore, we recommend clinicians to include the axial radiograph view during the evaluation of patients with medial epicondyle fractures. CLINICAL RELEVANCE: This study provides further insight into the location and orientation of the medial humeral epicondyle physis, and further supports the improved accuracy of the distal humerus axial radiograph at detecting displacement in medial epicondyle fractures.

Testing of Direct Neurorrhaphy Strain.

PURPOSE: To investigate the ideal suture material to test strain at nerve repair sites. Based on nerve strain tolerance, we aimed to determine which suture reliably failed by an average of 5% and a maximum of 8% strain when loaded to failure. METHODS: The median nerve of 19 cadavers was exposed in the distal forearm, transected proximally, and attached to a spring gauge. It was marked 5 cm on either side of its midpoint to measure strain. A laceration was created at its midpoint. We performed a tension-free end-to-end repair with a single epineural suture. Load to failure of the repair site was recorded. We recorded strain at failure and mode of failure (pullout vs breakage). Eight different sutures were tested: 6-0, 8-0, 9-0, and 10-0 nylon; and 6-0, 7-0, 8-0, and 10-0 polypropylene. RESULTS: Average strain at failure of 9-0 nylon most closely approximated 5% (4.9%). Moreover, 8-0 polypropylene and 10-0 nylon and polypropylene failed with average strains less than 5% and a maximum strain of failure less than 8%. Regardless of type, 6-0 to 8-0 caliber suture failed primarily by pullout of the suture from the epineurium whereas 9-0 and 10-0 nylon and polypropylene failed by suture breakage. Decreased precision through increased variability was seen when testing sutures failing via pullout. CONCLUSIONS: Nylon suture size 8-0 has been advocated as the suggested intraoperative aid to test strain at nerve repair sites. Our study suggests that 9-0 nylon may be a more appropriate testing suture because of its more predictable failure via breakage and its failure by a threshold of 5% to 8% strain. Although 8-0 nylon and polypropylene may also represent reasonable testing sutures, 8-0 nylon failed on average above 5% strain, with strains exceeding 8%, and both failed via the mechanism of pullout. CLINICAL RELEVANCE: This study's findings provide information for surgeons attempting to decide during surgery whether to perform direct nerve repair.

Submuscular Versus Subcutaneous Ulnar Nerve Transposition: A Cadaveric Model Evaluating Their Role in Primary Ulnar Nerve Repair at the Elbow.

PURPOSE: To investigate the length gained from subcutaneous and submuscular transposition of the ulnar nerve at the elbow. Specifically, the study aimed to define an expected nerve gap able to be overcome, and to determine if a difference between transposition techniques exists. METHODS: Eleven cadaveric specimens from the scapula to fingertip were procured. In situ decompression and mobilization of the ulnar nerve at the elbow followed by simulated laceration of the nerve was performed. Nerves were marked 5 mm from the laceration site to facilitate overlap measurement and to simulate nerve end preparation to viable fascicles before primary coaptation. Nerve ends were attached to spring gauges set at 100 g of tension (strain ≤ 10%). Measurements of nerve overlap were obtained in varying degrees of wrist (0°, 30°, 60°) and elbow (0°, 15°, 30°, 45°, 60°, 90°) flexion. Measurements were performed after in situ decompression and mobilization, and then repeated after both subcutaneous and submuscular transposition. RESULTS: Ulnar nerve transposition was found to increase nerve overlap at an elbow flexion of 30° or greater. No difference was seen between subcutaneous and submuscular transpositions at all wrist and elbow positions. In situ decompression and mobilization alone provided an average of 3.5 cm of length gain with the elbow extended. Transposition in conjunction with clinically feasible wrist and elbow flexion (30° and 60°, respectively) provided 5.2 cm of length gain. Controlling for mobilization, a statistically significant increase in overlap of approximately 2 cm was gained from transposition. CONCLUSIONS: Although mobilization combined with wrist and elbow flexion may afford substantial gap reduction and should be used initially when approaching proximal ulnar nerve lacerations, transposition should be considered when faced with a large nerve gap greater than 3 cm at the elbow. No difference was seen between submuscular and subcutaneous transposition techniques. CLINICAL RELEVANCE: This study defines the extent an ulnar nerve gap at the elbow can be overcome by in situ mobilization, joint positioning, and transposition. It additionally compares the efficacy of submuscular and subcutaneous transposition techniques in closing this gap.

Pediatric Scaphoid Proximal Pole Nonunion With Avascular Necrosis.

A 13-year-old, right hand-dominant, otherwise healthy boy presented with left wrist pain 19 months after a nonmotorized scooter injury. Radiographs and magnetic resonance imaging at presentation demonstrated proximal pole scaphoid nonunion with avascular necrosis of the proximal fragment. Operative and nonsurgical treatment options were discussed and the family elected for an attempt at nonsurgical management. The patient was placed in a short-arm thumb spica cast, with a window for a bone stimulator, for 14 weeks. At the conclusion of the treatment, the pain had resolved and x-ray and computed tomography scan demonstrated bony union. The authors recommend considering an initial trial of nonsurgical management for treatment of all pediatric scaphoid nonunions.

Effects of Hand Fellowship Training on Rates of Endoscopic and Open Carpal Tunnel Release.

PURPOSE: To investigate rates, trends, and complications for carpal tunnel release (CTR) related to fellowship training using the American Board of Orthopaedic Surgery Part II Database. METHODS: We searched the American Board of Orthopaedic Surgery database for patients with carpal tunnel syndrome who underwent either open carpal tunnel release (OCTR) or endoscopic (ECTR) from 2003 to 2013. Cases with multiple treatment codes were excluded. Data were gathered on geographic location, fellowship, and surgical outcomes. Data were then divided into 2 cohorts: hand fellowship trained versus non-hand fellowship trained. We performed analysis with chi-square tests of independence and for trend. RESULTS: Overall, 12.4% of all CTRs were done endoscopically. Hand fellowship-trained orthopedists performed about 4.5 times the number of ECTR than did non-hand fellowship-trained surgeons. An increasing trend over time of ECTR was seen only among the hand fellowship cohort. The northwest region of the United States had the highest incidence (23.1%) of ECTR, and the Southwest the lowest incidence (5.9%). The complication incidence associated with CTR overall was 3.6%, without a significant difference between ECTR and OCTR. Within the hand fellowship cohort the complication incidence for ECTR was significantly less than for OCTR. There was no difference in overall complication rates with ECTR and OCTR between the 2 cohorts. Wound complications were higher with OCTR (1.2% vs 0.25%) and nerve palsy with ECTR (0.66% vs 0.27%); with postoperative pain equivalent between techniques independent of fellowship training. CONCLUSIONS: Within the United States from 2003 to 2013, the rate of ECTR increased, as did complications. However, complication rates remained low in the first 2 years of practice. Hand fellowship-trained surgeons performed more ECTR than did non-hand fellowship-trained orthopedic surgeons, and both groups had similar complication rates. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Asymptomatic hip/groin pathology identified on magnetic resonance imaging of professional hockey players: outcomes and playing status at 4 years' follow-up.

PURPOSE: The purpose of this study was to evaluate the clinical outcomes and playing status of professional hockey players 4 years after they underwent bilateral magnetic resonance imaging (MRI) of asymptomatic hips. METHODS: Twenty-one professional hockey players with no previous hip/groin pain underwent hip/pelvis MRI. Each MRI study was evaluated by 3 subspecialty-trained musculoskeletal radiologists for alpha-angle measurement and the presence of adductor-abdominal rectus abnormalities, acetabular labral tears, osteochondral lesions of the femoral head or acetabulum, hip effusion, adjacent muscle contusions or strain injury, and stress fractures. The MRI findings of the players were previously published. In the present study, each athlete was followed up by (1) completion of a questionnaire assessing hip/groin dysfunction at 1 and 2 years' follow-up and (2) number of games played over the course of the next 4 years. A significant difference in the number of games played was considered when a player missed more than 5 games compared with the index year. RESULTS: We enrolled 21 players in the study. Of these players, 4 had no abnormality bilaterally, 10 had muscle strain and/or tendinosis in 1 or both hips, and 15 had labral tears identified in 1 or both hips. Eight players had a combination of labral tears and muscle strain/tendinosis. Of 21 professional hockey players, 16 (76%) and 14 (67%) were available at 1 and 2 years' follow-up, respectively. Nineteen of 21 players (90%) continued to play professional hockey at 4 years' follow-up. The development of any hip and/or pelvis symptoms occurred in only 3 players (14%) within 4 years. Only 1 of the 3 players missed any games because of hip and/or pelvis symptoms. The affected player missed several games because of proximal iliotibial band symptoms that occurred in the third year after MRI. CONCLUSIONS: Hip/pelvis pathology is commonly uncovered on MRI of asymptomatic hockey players; however, this pathology does not produce symptoms or result in missed games within 4 years in most players. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

High prevalence of pelvic and hip magnetic resonance imaging findings in asymptomatic collegiate and professional hockey players.

BACKGROUND: Prior retrospective studies have reported magnetic resonance imaging (MRI) findings of common adductor-abdominal rectus enthesopathy and acetabular labral tear in athletes treated for athletic pubalgia and hip pain. The true prevalence of these findings and association with symptoms in this population is unknown. PURPOSE: This study was undertaken to determine the prevalence of pelvic and hip MRI findings and association with clinical symptoms in professional and collegiate hockey players. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The study included 21 professional and 18 collegiate hockey players. Self-reported symptoms were measured using a modified Oswestry Disability Questionnaire. Participants underwent 3-T MRI evaluation of the pelvis and hips. The MRI scans were interpreted independently by 3 musculoskeletal radiologists in 2 sessions separated by 3 months using a 5-point Likert scale to assess for features associated with common adductor-abdominal rectus dysfunction and hip pathology. To estimate prevalence, MRI findings rated 4 or higher on 4 of the 6 interpretations were considered positive. A variance component analysis was applied to determine intrareader and interreader reliability and the lower 95% confidence limits (CLs). RESULTS: No participants reported symptoms related to pelvic or hip disorders. The MRI findings of common adductor-abdominal rectus dysfunction were observed in 14 of 39 participants (36%) and hip pathologic changes in 25 of 39 (64%). There was moderate agreement between readings, with intrareader and interreader reliabilities ranging from 0.37 to 1.00. The interreader reliability was less for evaluation of hip pathologic abnormalities than for groin pathologic abnormalities, with the lowest reliability observed in reporting of hip osteochondral lesions (0.37 with lower 95% CL of 0.22) and fluid in the primary cleft (0.45 with lower 95% CL of 0.29) and perfect reliability in the absence of effusion and abdominal rectus tendon tears. Overall, 30 of 39 (77%) asymptomatic hockey players demonstrated MRI findings of hip or groin pathologic abnormalities. CONCLUSION: Given the high prevalence of MRI findings in asymptomatic hockey players, it is necessary to cautiously interpret the significance of these findings in association with clinical presentation. Future investigations will determine whether these asymptomatic findings predict future disabilities.