Krystle A. Hearns

Anatomy of the Thumb Metacarpophalangeal Ulnar and Radial Collateral Ligaments

PURPOSE To describe the origin and insertion of the ulnar (UCL) and radial collateral ligaments (RCL) of the thumb metacarpophalangeal (MCP) joint. METHODS We dissected 18 UCLs and 18 RCLs from fresh-frozen human cadaveric thumbs. We removed all soft tissue overlying the MCP joint, isolating the proper collateral ligaments. We detached the collateral ligaments from the bone while marking their origin and insertion points and measured these attachment sites in relation to bony landmarks by digital photo analysis. RESULTS The center of the UCL origin at the metacarpal was 4.2 mm from the dorsal surface and 5.3 mm from the articular surface. The dorsal aspect of the metacarpal origin site was 2.1 mm from the dorsal edge of the metacarpal. The center of the phalangeal insertion was 2.8 mm from the volar surface and 3.4 mm from the articular surface. The volar aspect of the phalangeal insertion site was 0.7 mm from the volar edge of the phalanx. The center of the RCL origin at the metacarpal was 3.5 mm from the dorsal surface and 3.3 mm from the articular surface. The dorsal aspect of the metacarpal origin site was 1.5 mm from the dorsal edge of the metacarpal. The center of the phalangeal insertion was 2.8 mm from the volar surface and 2.6 mm from the articular surface. The volar aspect of the phalangeal insertion site was 0.5 mm from the volar edge of the phalanx. CONCLUSIONS Our study accurately defined the origin and insertion sites of the UCL and RCL of the thumb MCP joint. CLINICAL RELEVANCE An accurate definition of the anatomical origin and insertion points of the thumb MCP UCL and RCL may allow for more successful surgical repair and reconstruction.

Opinions Regarding the Management of Hand and Wrist Injuries in Elite Athletes

Injuries to the hand and wrist are commonly encountered in athletes. Decisions regarding the most appropriate treatment, the timing of treatment, and return to play are made while balancing desires to resume athletic activities and sound orthopedic principles. Little recognition in the literature exists regarding the need for a different approach when treating these injuries in elite athletes and the timing to return to play. This study explored the complexities of treating hand and wrist injuries in the elite athlete. Thirty-seven consultant hand surgeons for teams in the National Football League, National Basketball Association, and Major League Baseball completed a brief electronic survey about the management of 10 common hand injuries. Notable variability existed in responses for initial management, return to protected play, and return to unprotected play for all injuries, aside from near consensus agreement (94%) that elite athletes with stable proximal interphalangeal dislocations could immediately return to protected play. Basketball surgeons were less likely to recommend early return to protected play than non-basketball surgeons. Baseball surgeons were more likely to recommend early unprotected play after scaphoid fixation. Football surgeons were more likely to recommend earlier return to protected play after thumb ulnar collateral ligament injuries, whereas basketball surgeons were less likely to recommend earlier return to protected play. This study demonstrated wide variability in how consultant hand surgeons approach the treatment of hand and wrist injuries. The findings emphasize the need to individually tailor treatment decisions to the patients desires and demands, particularly in high-performance athletes.

Early Results of Surgical Intervention for Elbow Deformity in Cerebral Palsy Based on Degree of Contracture

PURPOSE Elbow flexion posture, caused by spasticity of the muscles on the anterior surface of the elbow, is the most common elbow deformity seen in patients with cerebral palsy. This study retrospectively evaluated early results of 2 surgical interventions for elbow flexion deformities based on degree of contracture. We hypothesized that by guiding surgical treatment to degree of preoperative contracture, elbow extension and flexion posture angle at ambulation could be improved while preserving maximum flexion. METHODS Eighty-six patients (90 elbows) were treated for elbow spasticity due to cerebral palsy. Seventy-one patients (74 elbows) were available for follow-up. Fifty-seven patients with fixed elbow contractures less than 45° were surgically treated with a partial elbow muscle lengthening, which included partial lengthening of the biceps and brachialis and proximal release of the brachioradialis. Fourteen patients (17 elbows) with fixed elbow contractures ≥ 45° had a more extensive full elbow release, with biceps z-lengthening, partial brachialis myotomy, and brachioradialis proximal release. RESULTS Age at surgery averaged 10 years (range, 3-20 y) for partial lengthening and 14 years (range, 5-20 y) for full elbow release. Follow-up averaged 22 months (range, 7-144 mo) for partial lengthening and 18 months (range, 6-51 mo) for full elbow release. Both groups achieved meaningful improvement in flexion posture angle at ambulation, active and passive extension, and total range of motion. Elbow flexion posture angle at ambulation improved by 57° and active extension increased 17° in the partial lengthening group, with a 4° loss of active flexion. In the full elbow release group, elbow flexion posture angle at ambulation improved 51° and active extension improved 38°, with a loss of 19° of active flexion. CONCLUSIONS Surgical treatment of spastic elbow flexion in cerebral palsy can improve deformity. We obtained excellent results by guiding the surgical intervention by the amount of preoperative elbow contracture. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

Mechanics of an Anatomical Reconstruction for the Thumb Metacarpophalangeal Collateral Ligaments

PURPOSE This study biomechanically evaluated a technically easy variation of anatomical reconstruction of the thumb metacarpophalangeal (MCP) joint ulnar (UCL) and radial (RCL) collateral ligaments. Based on previous work describing the anatomical origin and insertion of these ligaments, we hypothesized that, using these attachment points, joint stability would be restored without significant loss of MCP flexion. METHODS The collateral ligaments were isolated in 30 cadaveric thumbs (15 UCLs and 15 RCLs). A cyclical load was applied to the MCP joint to assess flexion, radial/ulnar deviation in neutral, and radial/ulnar deviation in 30° of flexion. The collateral ligaments were detached from the bone while their origin and insertion points were marked. Using these sites, anatomical ligament reconstruction was performed with a palmaris longus tendon graft and interference screw fixation. Cyclical testing was repeated on the reconstructed ligaments. RESULTS No significant difference was found between intact and reconstructed UCLs when tested for radial deviation in neutral, radial deviation in 30° of flexion, or total MCP flexion. No significant difference was found between intact and reconstructed RCLs when tested for ulnar deviation in neutral, ulnar deviation in 30° of flexion, or total MCP flexion. CONCLUSIONS Our anatomical reconstruction is simple and restores UCL and RCL anatomy as compared with current techniques in the literature by placing the origin and insertion at their anatomical points with use of an interference screw. Using these anatomical origins and insertions, we were able to restore the MCP flexion and stability seen in an intact ligament. CLINICAL RELEVANCE Our anatomical reconstruction offers a technically easy option for reconstruction of thumb MCP collateral ligament injuries, restoring joint stability without sacrificing flexion.

Anatomy of the Radial Collateral Ligament of the Index Metacarpophalangeal Joint

PURPOSE To describe the origin and insertion of the radial collateral ligament (RCL) of the index metacarpophalangeal (MP) joint, relative to the MP joint line and other landmarks readily discernible intraoperatively. METHODS We dissected 17 fresh-frozen human cadaveric index fingers. We removed all overlying soft tissue from the MP joint except for the proper RCL. We dissected the RCL from its original insertion under loupe magnification while concurrently marking the ligamentous origin and insertion points. We measured distances of these points in relation to the bony landmarks (dorsal, articular, and volar surfaces) using digital photo analysis. The same observer recorded all measurements to reduce systematic error. RESULTS The center of the metacarpal attachment of the RCL was located 5.4 ± 1.1 mm from the dorsal border of the metacarpal, 8.0 ± 2.2mm from the volar border of the metacarpal, and 10.3 ± 3.2mm from the articular surface of the MP joint. The total width and height of the metacarpal origin site were 5.8 ± 1.6 and 6.4 ± 1.4 mm, respectively. The center of the proximal phalanx attachment of the RCL was located 6.8 ± 1.4 mm from the dorsal border of the proximal phalanx, 5.7 ± 0.9 mm from the volar border of the proximal phalanx, and 4.4 ± 0.8mm from the articular surface of the MP joint. The total width and height of the phalangeal origin site were 5.0 ± 1.1 and 5.7 ± 0.9 mm, respectively. CONCLUSIONS Our study defines the anatomic origin and insertion of the RCL of the index MP joint in relation to landmarks that are identifiable during surgery. CLINICAL RELEVANCE We believe this information will be useful to surgeons when repairing or reconstructing the RCL, allowing for recreation of normal RCL anatomy.

Relative Contribution of the Subsheath to Extensor Carpi Ulnaris Tendon Stability: Implications for Surgical Reconstruction and Rehabilitation

PURPOSE To identify the varying contributions of the proximal and distal portions of the subsheath of the extensor carpi ulnaris (ECU) to its stability, evaluate the correlation of ulnar groove depth and ECU subluxation, and observe the effect of forearm and wrist positions on ECU stability. METHODS Extensor carpi ulnaris tendon position relative to the ulnar groove was measured in 10 human cadaveric specimens with the subsheath intact, partially sectioned (randomized to distal or proximal half), and fully sectioned. Measurements were obtained in 9 positions: forearm supinated, neutral, and pronated and wrist extended, neutral, and flexed. Ulnar groove depth was measured on all specimens. RESULTS In 7 of 10 specimens with an intact subsheath, the ECU tendon subluxated out of the groove in at least 1 forearm-wrist position. We noted the subluxation of the ECU tendon in all wrist-forearm positions with the exception of pronation-extension in at least 1 specimen. For partial subsheath sectioning, tendon displacement markedly increased after distal subsheath sectioning but not after proximal sectioning. For full subsheath sectioning, wrist flexion produced subluxation in all forearm positions, and forearm supination produced subluxation in all wrist positions. Maximum displacement occurred in supination-flexion. There was no correlation between ulnar groove depth and ECU subluxation. CONCLUSIONS Mild tendon subluxation occurred in the intact specimens in most tested positions. Two positions were remarkable for their consistency in maintaining the tendon within the groove: pronation-neutral and pronation-extension. In fully sectioned specimens, the greatest subluxation occurred in supination-flexion, with supination and flexion independently producing subluxation. Partial sectioning demonstrated that the distal portion of the subsheath played a more important role than the proximal portion in stabilizing the ECU. CLINICAL RELEVANCE Subsheath repair or reconstruction should target the distal portion of the subsheath. During postinjury rehabilitation or following surgical reconstruction, combined forearm supination and wrist flexion should be avoided.

Long-Term Results Following Surgical Treatment of Elbow Deformity in Patients With Cerebral Palsy

PURPOSE To evaluate the long-term results of surgical intervention for elbow flexion deformity in cerebral palsy. We hypothesized that improvements in elbow extension and flexion posture angle at ambulation would be maintained over time with preservation of active flexion. METHODS A total of 23 patients (23 elbows) were available for long-term follow-up. Patients had fixed elbow contractures less than 45° and were treated with partial elbow muscle lengthening. Active and passive range of motion and elbow flexion posture during ambulation were measured at each follow-up, and longitudinal results were compared. RESULTS Active extension and flexion posture angle during ambulation improved 12° and 63°, respectively, with an 8° loss of active flexion. CONCLUSIONS Soft tissue lengthening of the anterior elbow can provide statistically significant lasting improvements in active extension and flexion posture during ambulation in patients with cerebral palsy. Our long-term findings substantiate previously reported short-term results. TYPE OF STUDY/LEVEL OF EVIDENCE Therapeutic IV.

Comparison of In Vitro Motion and Stability Between Techniques for Index Metacarpophalangeal Joint Radial Collateral Ligament Reconstruction

PURPOSE To evaluate a technique using interference screws to secure a tendon graft for reconstruction of the radial collateral ligament (RCL) of the index finger metacarpophalangeal (MCP) joint. We hypothesized that this technique would provide equivalent stability and flexion as a 4-tunnel reconstruction. METHODS We isolated the RCL in 17 cadaveric index fingers. A cyclic load was applied to the intact RCL across the MCP joint to assess flexion, ulnar deviation at neutral (UD 0), and ulnar deviation at 90° of MCP joint flexion (UD 90). The RCL was excised from its bony origin and insertion. We performed each reconstruction (4-tunnel and interference screw) sequentially on each specimen in a randomized order using a palmaris longus tendon graft. We repeated testing after each reconstruction and compared differences from the intact state between techniques using paired t-tests for all joint positions (flexion/UD 0/UD 90). RESULTS There was no statistically significant difference in UD 0 or UD 90 between the intact state and after interference screw reconstruction. Compared with the intact state, there was significantly less UD 0 and significantly more UD 90 after 4-tunnel reconstruction. There was no statistically significant difference between techniques when we compared changes in -UD 0 or UD 90. Change in flexion was statistically significantly different, which indicates that the interference screw technique better replicated intact MCP joint flexion compared with the 4-tunnel technique. CONCLUSIONS Interference screw reconstruction of the index RCL provides stability comparable to 4-tunnel reconstruction and is less technically challenging. These results substantiate our clinical experience that the interference screw technique provides an optimal combination of stability and flexion at the index MCP joint. CLINICAL RELEVANCE Using an interference screw to reconstruct the index RCL is less challenging than 4-tunnel reconstruction and provides stability and range of motion that closely resemble the native MCP joint.

Variable Bone Density of Scaphoid: Importance of Subchondral Screw Placement

Abstract Background Ideal internal fixation of the scaphoid relies on adequate bone stock for screw purchase; so, knowledge of regional bone density of the scaphoid is crucial. Questions/Purpose The purpose of this study was to evaluate regional variations in scaphoid bone density. Materials and Methods Three‐dimensional CT models of fractured scaphoids were created and sectioned into proximal/distal segments and then into quadrants (volar/dorsal/radial/ulnar). Concentric shells in the proximal and distal pole were constructed in 2‐mm increments moving from exterior to interior. Bone density was measured in Hounsfield units (HU). Results Bone density of the distal scaphoid (453.2 ± 70.8 HU) was less than the proximal scaphoid (619.8 ± 124.2 HU). There was no difference in bone density between the four quadrants in either pole. In both the poles, the first subchondral shell was the densest. In both the proximal and distal poles, bone density decreased significantly in all three deeper shells. Conclusion The proximal scaphoid had a greater density than the distal scaphoid. Within the poles, there was no difference in bone density between the quadrants. The subchondral 2‐mm shell had the greatest density. Bone density dropped off significantly between the first and second shell in both the proximal and distal scaphoids. Clinical Relevance In scaphoid fracture ORIF, optimal screw placement engages the subchondral 2‐mm shell, especially in the distal pole, which has an overall lower bone density, and the second shell has only two‐third the density of the first shell.

Importance of Computed Tomography in Determining Displacement in Scaphoid Fractures

Abstract Background Displaced scaphoid fractures have a relatively high rate of nonunion. Detection of displacement is vital in limiting the risk of nonunion when treating scaphoid fractures. Questions/Purpose We evaluated the ability to diagnose displacement on radiographs and computed tomography (CT), hypothesizing that displacement is underestimated in assessing scaphoid fracture by radiograph compared with CT. Materials and Methods Thirty‐five preoperative radiographs and CT scans of acute scaphoid fractures were evaluated by two blinded observers. Displacement and angular deformity were measured, and the fracture was judged as displaced or nondisplaced. Scapholunate, radiolunate, and intrascaphoid angles were measured. Radiograph and CT measurements between nondisplaced and displaced fractures were compared. Intraobserver reliability was measured. Results Reader 1 identified 12 fractures as nondisplaced on radiograph, but displaced on CT (34%). Reader 2 identified 9 fractures as nondisplaced on radiograph, but displaced on CT (26%). For displaced fractures, the mean intrascaphoid angle was over three times greater when measured on CT than on radiograph (56 vs. 16 degrees). Scapholunate angle >65 degrees and radiolunate angle >16 degrees were significantly associated with displacement on CT. Interobserver reliability for diagnosing displacement was perfect on CT but less reliable on radiograph. Conclusion Scaphoid fracture displacement on CT was identified in 26 to 34% of fractures that were nondisplaced on radiograph, confirming that radiographic evaluation alone underestimates displacement. These results underscore the importance of CT scan in determining displacement and angular deformity when evaluating scaphoid fractures, as it may alter the decision on treatment and surgical approach to the fracture. We recommend considering CT scan to evaluate all scaphoid fractures. Level of Evidence Level III.