Faculty Bibliography

PURPOSE: To compare the biomechanical characteristics of 3 methods of scapholunate (SL) ligament reconstruction, including 1 that provides a biological central axis tether. METHODS: Twelve fresh-frozen cadaver limbs were mounted on a jig that allowed for wrist and finger motion by tendon loading. The specimens were randomized to receive the SL axis method (SLAM) reconstruction, the Blatt capsulodesis (BC), or the modified Brunelli tenodesis (MBT). Fluoroscopic images were taken to measure the SL interval and SL angle in various positions. The specimens were evaluated in 4 states: intact, with the SL and radioscaphocapitate ligaments cut, after reconstruction, and after reconstruction followed by 100 cycles of simulated motion. RESULTS: After cycling, the MBT and the SLAM reconstructions performed significantly better than the BC in recreating the intact SL interval in a clenched fist posture. The SLAM SL interval trended to be closer to the intact state than the MBT SL interval. The SLAM reconstruction also trended toward greater restoration of the native SL angle in the clenched fist posture than either the MBT or the BC. CONCLUSIONS: The SL ligament reconstruction that uses a 2-tailed tendon autograft placed along the axis of rotation of the SL joint and secured both at the scaphoid and the lunate minimized creep and reconstructed the critical dorsal SL ligament. The SLAM achieved improved the SL interval and SL angle correction compared with conventional techniques of SL ligament reconstruction. CLINICAL RELEVANCE: The SLAM method may be a useful alternative for SL ligament reconstruction.

The aim of this study was to quantify the amount of tendon excursion and load experienced during simulated active and passive rehabilitation exercises. Six cadaver specimens were utilized to examine tendon excursion and load. Lateral fluoroscopic images were used to measure the excursions of metal markers placed in the flexor digitorum superficialis and profundus tendons of the index, middle, and ring fingers. Measurements were performed during ten different passive and active simulated motions. Mean tendon forces were higher in all active versus passive movements. Blocking movements placed the highest loads on the flexor tendons. Active motion resulted in higher tendon excursion than did passive motion. Simulated hook position resulted in the highest total tendon excursion and the highest inter-tendinous excursion. This knowledge may help optimize the management of the post-operative exercise therapy regimen.

PURPOSE: To assess the ability of headless compression screws to maintain immobile bony contact throughout wrist cycling following simulated 4-corner arthrodesis. Our hypothesis was that the screw constructs would not permit displacement of the carpal bones and, therefore, could tolerate early postoperative range of motion in vivo. METHODS: Using 6 matched-paired cadaveric arms, 4-corner arthrodesis was performed using an all-cannulated compression screw construct (capitolunate, lunotriquetral, and triquetrohamate screws) or a partial compression screw combined with partial K-wire construct (2 crossing capitolunate screws with the lunotriquetral and triquetrohamate interfaces immobilized with 2 K-wires). Wrists were mounted and cycled 5,000 times. Intercarpal distances were measured at 0, 100, 1,000, and 5,000 cycles at fixed points of passive flexion. Because previously published studies considered intercarpal distances of greater than 1 mm as significant, we defined fixation failure as greater than 0.5 mm gapping. RESULTS: Neither screw construct showed any significant intercarpal gapping at any point during the experimental cycling (largest average intercarpal gapping was 0.2 mm). There were no significant differences between the constructs regarding gapping at any point. CONCLUSIONS: In this biomechanical model, cannulated compression screws effectively resist significant intercarpal gapping during early motion after 4-corner arthrodesis. This may allow for immediate postoperative range of motion. CLINICAL RELEVANCE: Early gentle range of motion may be possible immediately following 4-corner arthrodesis using a construct consisting of headless compression screws.

Intrinsic paralysis can be the manifestation of a variety of pathologic entities (stroke, cerebral palsy, Charcot-Marie-Tooth, muscular dystrophy, leprosy, trauma, cervical disease, and compressive and metabolic neuropathies). Patients present with a spectrum of clinical findings dependent on the cause and severity of the disease. The 3 main problems caused by intrinsic weakness of the fingers are clawing with loss of synchronistic finger flexion, inability to abduct/adduct the digits, and weakness of grip. Clawing is defined as hyperextension of the metacarpophalangeal joints and flexion of the interphalangeal joints. This article describes the clinical evaluation and surgical treatment options for claw hand

PURPOSE: Trauma to the digits often leaves soft tissue defects with exposed bone, joint, and/or tendon that require soft tissue replacement. The objective of this study was to evaluate the effectiveness of acellular dermal regeneration template combined with full-thickness skin grafting for soft tissue reconstruction in digital injuries with soft tissue defects. METHODS: Acellular dermal regeneration template was used to reconstruct digital injuries with exposed bone, joint, tendon, and/or hardware not amenable to treatment with healing by secondary intention, rotation flaps, or primary skin grafts. Acellular dermal regeneration template was applied to 21 digits in 17 patients. Nineteen digits had exposed bone, 8 digits had exposed tendon, 6 digits had exposed joints, and 2 digits had exposed hardware. The acellular dermal regeneration template was sutured over the soft tissue defect. Over 3 weeks, a neodermis formed. The superficial silicone layer of the acellular dermal regeneration template was removed, and the digits received full-thickness epidermal autografting with cotton bolster. RESULTS: The duration of postoperative follow-up extended to a minimum of 12 months. For the injury sites where acellular dermal regeneration template was applied, the total area of application ranged from 1 cm(2) to 24 cm(2), with the largest individual site measuring 12 cm(2). Twenty of 21 digits demonstrated 100% incorporation of the acellular dermal regeneration template skin substitute. One digit that had sustained multilevel trauma developed necrosis requiring revision amputation. Full-thickness epidermal autografting was performed an average of 24 days after acellular dermal regeneration template skin substitute application and demonstrated a 100% take in 16 of 20 digits and partial graft loss of 15% to 25% in 4 of 20 digits that did not require further treatment. CONCLUSIONS: Acellular dermal regeneration template combined with secondary full-thickness skin grafting is an effective method of skin reconstruction in complex digital injuries with soft tissue defects involving exposed bone, tendon, and joint. The neodermis increases tissue bulk and facilitates epidermal autografting with digital injuries that otherwise would require flap coverage or skeletal shortening of the digit. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV

SAR exploration of the central diamine, benzyl, and terminal aminoalkoxy regions of the N-cyclic azaalkyl benzamide series led to the identification of very potent human urotensin-II receptor antagonists such as 1a with a K(i) of 4 nM. The synthesis and structure-activity relationships (SAR) of N-cyclic azaalkyl benzamides are described.