Adam J. Mirarchi

Cadaveric Biomechanical Analysis of the Distal Radioulnar Joint: Influence of Wrist Isolation on Accurate Measurement and the Effect of Ulnar Styloid Fracture on Stability

PURPOSE Distal radioulnar joint (DRUJ) instability can be tested using biomechanical cadaveric models, but inadequate isolation of the DRUJ during instability testing may introduce measurement error. The first goal of this investigation was to develop an effective model for isolating the DRUJ during biomechanical cadaveric testing. The second goal was to use this model to measure the effect of ulnar styloid fracture and subsequent repair on DRUJ kinematics in cadaveric specimens. METHODS Five fresh cadaveric arms were tested using a Biodex System 3 device. The humerus was clamped firmly, the forearm rotated freely, and the hand/carpus was attached to the Biodex device. Three methods of DRUJ isolation were tested. In method 1, the specimen was firmly clamped at the midshaft humerus and the hand/carpus was clamped. In method 2, the distal radius was additionally fixed to the carpal clamp to reduce carpal motion. In method 3, proximal fixation of the olecranon to an elbow rest was added. Testing was done before ulnar styloid osteotomy (group 1), after osteotomy through dorsal capsulotomy (group 2), and after styloid fragment repair with a screw (group 3). Twelve pronation-supination cycles were performed while work of rotation, maximum pronation torque, and maximum supination torque for each method and group were recorded. RESULTS Analysis of clamping methods showed work of rotation, maximum pronation torque, and maximum supination torque for method 3 were greater than those for methods 1 and 2. Analysis of groups showed the following statistically significant trends for work of rotation: group 1 >>> group 3 > group 2. Maximum supination torque similarly showed statistically significant differences: group 1 >>> group 3 > group 2. Maximum pronation torque showed a similar trend: group 1 >>> group 3 > group 2. However, in contrast with work of rotation and maximum supination torque, group 3 maximum pronation torque was not statistically different from that of group 2. CONCLUSIONS Increased work of rotation represents decreased joint laxity. Maximum supination torque and maximum pronation torque assess soft tissue restraints at joint end points. Method 3 showed the greatest values in these variables, indicating reduced elbow and carpal motion and better DRUJ isolation. Work of rotation and maximum supination torque in group 3 were increased from those of group 2 but not restored to group 1 values. Styloid fixation restores some soft tissue tension but laxity persists. Maximum pronation torque in group 3 was not increased significantly from that of group 2, perhaps from dorsal capsulotomy causing soft tissue injury and laxity not corrected with fixation. The influence of ulnar styloid fracture on dynamic DRUJ kinematics can be demonstrated in this model.

Late Reconstruction of Median Nerve Palsy

The median nerve provides sensory innervation to the radial aspect of the hand, including the palm, thumb, index, long, and half of the ring fingers. It provides motor innervation to most of the volar forearm musculature and, importantly, to m ost of thenar musculature. The main goal of median nerve reconstructive procedures is to restore thumb opposition. There are a variety of transfers that can achieve this goal but tendon transfers must recreate thumb opposition, which involves 3 basics movements: thumb abduction, flexion, and pronation. Many tendon transfers exist and the choice of tendon transfer should be tailored to the patients needs.

Effectiveness of a Microvascular Surgery Training Curriculum for Orthopaedic Surgery Residents

BACKGROUND The safe and effective acquisition of microvascular surgical skills is a challenge for any residency program. Variable clinical exposure to microsurgery, premiums on operating room efficiency, and a steep learning curve make these skills difficult to acquire through clinical experience alone. The purpose of this study was to determine the effectiveness of a training curriculum on the development of microvascular surgical skills in our orthopaedic residents. METHODS A microvascular training curriculum was completed during each third-year residents rotation on the hand and upper-extremity service. The training cycle began with learning the basics of microvascular surgery on nonliving models and progressed to performing end-to-end arterial anastomoses on a live rat femoral artery in the second session. Outcome evaluations consisted of the Global Rating Scale score, achievement of patency, and time to completion. T test analyses of Global Rating Scale scores, achievement of patency, and time to completion were conducted to determine significance (p < 0.05). RESULTS All residents significantly improved (p < 0.005) on Global Rating Scale scores from a mean score (and standard deviation) of 15 ± 4 points for the initial score to 20 ± 3 points for the post-test score. Of the twelve residents, patency was achieved by eleven at the final evaluation, compared with six before training. Time to completion of the anastomosis also significantly improved (p < 0.005), from a mean of 37:17 ± 8:41 minutes for the initial time to 24:46 ± 5:32 minutes for the final time. CONCLUSIONS In an effort to improve the microvascular surgical skills of orthopaedic residents at our institution, a microvascular training curriculum was developed and was implemented. This curriculum was effective at improving resident microvascular surgical skills at the completion of an eight-week course.

Complications Following Collagenase Treatment for Dupuytren Contracture

Background: Collagenase Clostridium histolyticum (CCH) injection and manipulation is a relatively new method for treating Dupuytren contracture that is growing in popularity. Although side effects such as swelling and ecchymosis are common, they are typically mild and self-limited. Major complications are rare but have included flexor tendon rupture and complex regional pain syndrome. Methods: This study describes a case report of 2 patients seen at our institution. Results: Here, we report 2 patients seen at our institution each with different, yet serious complications after CCH injection and manipulation. One patient had extensive skin loss and chose amputation over reconstruction. The other patient had loss of perfusion and required finger amputation. Conclusions: Although it is unclear how directly the administration of CCH is connected to the observed complications, physicians should recognize the potential for serious rare complications in any treatment of Dupuytren contracture.

Layered Plating for Complex Fractures

Complex fractures provide a unique challenge to the musculoskeletal surgeon. Traditional fracture reduction techniques are not always feasible, and often difficult depending on the anatomic area involved. We describe a novel technique, called layered plating, which can ease anatomic reduction and fixation of complex fractures. The aim of this paper was to describe 3 applications for layered plating, including provisional reduction, stability enhancement, and endosteal plating. All of the patients in which this technique was used went on to clinical and radiographic healing.

Nonsurgical Treatment of Delayed-Onset Brachial Plexopathy Due to Hypertrophic Clavicular Callus: A Case Report

Clavicular fractures are common injuries that traditionally are managed nonsurgically without clinically significant sequelae. However, they may develop hypertrophic callus formation that compresses the brachial plexus. These cases may present months to years after initial injury with varying degrees of pain, paresthesia, and weakness on the affected side and usually are treated by surgical resection of the hypertrophic callus. We present a case of brachial plexopathy due to hypertrophic clavicular callus causing weakness and paresthesia. The plexopathy was confirmed with imaging and electrodiagnostic studies. This case was unusual in that resolution of symptoms was achieved nonsurgically.

Drill Penetration Injury to Extensor Tendons: A Biomechanical Analysis

Background: Little is known about extensor tendon failure following drill injury at the time of volar plate fixation. Our goals were to analyze extensor tendon injury following simulated drill penetration, and change in tendon displacement during cyclic loading following simulated drill penetration injury. Methods: Extensor pollicis longus (EPL) and extensor carpi radialis brevis (ECRB) tendons were harvested from 9 fresh frozen cadaveric arms. Eighteen EPL and 18 ECRB samples were created from harvested tendons. Drill penetration injury was performed in either a continuous or an oscillating mode. Injured tendons were subjected to 1200 cycles at 1- to 15-kg cyclic load at a frequency of 1 Hz, and analyzed for failure at drill sites and change in displacement throughout the testing cycle. Results: Ten EPL samples and 16 ECRB samples completed testing without failure. Tendon type (ECRB, EPL), mode of injury (continuous, oscillating), and location (proximal, distal) did not affect tendon displacement during loading. A single EPL tendon failed following continuous drill penetration injury. Extensor carpi radialis brevis samples had a mean change in displacement of 2.8 (standard deviation [SD]: 1.5 mm) and 5.9 mm (SD: 4.7 mm) for oscillating and continuous modes, respectively. Six EPL samples had a mean change in displacement of 4.7 (SD: 2.7 mm) and 4.3 mm (SD: 1.8 mm) for oscillating and continuous modes, respectively. Conclusions: Complete extensor tendon failure due to drill penetration was rare. Drill mode did not affect the degree of elongation. Increasing cyclic loading of extensor tendons after drill injury caused modest extensor tendon elongation.

Concurrent little leaguer's elbow and shoulder in a 15-year-old baseball pitcher and football quarterback.

Little leaguers elbow and Little leaguers shoulder are overuse pathologies seen in overhead-throwing athletes. No instance of simultaneously occurring pathologies has been published. A 15-year-old baseball pitcher and football quarterback developed pain in his throwing shoulder and elbow during spring baseball, which partially resolved with several months of rest. During fall football practice, he felt a pop and pain over his medial throwing elbow. Five days after the initial injury, medial elbow tenderness, mild swelling, and decreased range of motion were noted. Radiographs revealed a Salter I avulsion fracture of the medial humeral epicondyle (Little leaguers elbow) and a periosteal reaction along the lateral aspect of the humeral metadiaphysis with slight widening (Little leaguers shoulder). Surgical fixation of the medial epicondyle fracture and nonoperative treatment of the shoulder pathology were performed. Two-year follow-up radiographs showed a healed medial epicondylar fracture and resolution of the periosteal reaction of the humeral metadiaphysis. The patient returned to full activity and was starting quarterback for his football team. Biomechanical forces specific to overhead-throwing activities are associated with the development of Little leaguers elbow and shoulder. Treatments of both pathologies remain controversial, with either initial operative vs nonoperative care. In this patient, a good outcome was achieved with surgical fixation of the elbow fracture and conservative management of the shoulder pathology. Educating coaches and parents on proper throwing technique and pitching limits should be the first step in reducing the occurrence of either pathology in this population.

Median nerve injury associated with radial forearm free flap harvest

The radial forearm fasciocutaneous free flap has become a mainstay for head and neck reconstruction due to its versatility, soft tissue pliability, long vascular pedicle, low donor site morbidity, and potential for sensory reinnervation. Reported donor site morbidities include paresthesias, seromas, exposed tendon, and partial loss of skin graft coverage. Differences in wrist flexion, pinch strength, and sharp sensation in the anatomical snuffbox have been documented but are unrelated to subjective patient complaints. Major neural praxias of the median or ulnar nerve have not been reported. This report was approved by the institutional review board of our center.