Steve K. Lee

Repair of Flexor Digitorum Profundus to Distal Phalanx: A Biomechanical Evaluation of Four Techniques

PURPOSEnMany techniques for repair of the flexor digitorum profundus to the distal phalanx show excessive gapping with variable clinical results. The purpose of this study was to test the biomechanical characteristics of an anchor-button (AB) technique, as compared to 3 other techniques.nnnMETHODSnTwenty-four fresh-frozen human cadaveric fingers were randomized to 4 groups, 6 in each: group 1, 2-strand Bunnell suture button pullout technique; group 2, modified Kessler suture and 2 retrograde anchors; group 3: locking Krakow suture with 2 retrograde anchors; group 4, AB technique incorporating a 2-part repair, consisting of a locking dorsal Krakow suture with 2 retrograde anchors and a locking palmar Krakow suture fixed with a button. Tendon-to-bone gapping was measured after cyclical loading. Ultimate load to failure was measured at the end of 500 cycles.nnnRESULTSnThe AB technique resulted in significantly less gapping when compared to the other techniques. It also resulted in a significantly stronger repair compared to all the other groups with an average load to failure comparable to the native tendon-to-bone interface.nnnCONCLUSIONSnThe AB repair might allow for early active postoperative motion after repair of flexor digitorum profundus avulsion injuries and tendon reconstruction procedures; however, the soft tissue effects of this multistrand technique are unknown in clinical repairs.

Long-Nerve Grafts and Nerve Transfers Demonstrate Comparable Outcomes for Axillary Nerve Injuries

PURPOSEnTo compare the functional and EMG outcomes of long-nerve grafts to nerve transfers for complete axillary nerve palsy.nnnMETHODSnOver a 10-year period at a single institution, 14 patients with axillary nerve palsy were treated with long-nerve grafts and 24 patients were treated with triceps-to-axillary nerve transfers by the same surgeon (S.W.W.). Data were collected prospectively at regular intervals, beginning before surgery and continuing up to 11 years after surgery. Prior to intervention, all patients demonstrated EMG evidence of complete denervation of the deltoid. Deltoid recovery (Medical Research Council [MRC] grade), shoulder abduction (°), improvement in shoulder abduction (°), and EMG evidence of deltoid reinnervation were compared between cohorts.nnnRESULTSnThere were no significant differences between the long-nerve graft cohort and the nerve transfer cohort with respect to postoperative range of motion, deltoid recovery, improvement inxa0shoulder abduction, or EMG evidence of deltoid reinnervation.nnnCONCLUSIONSnThese data demonstrate that outcomes of long-nerve grafts for axillary nerve palsy are comparable with those of modern nerve transfers and question a widely held belief that long-nerve grafts do poorly. When healthy donor roots or trunks are available, long-nerve grafts should not be overlooked as an effective intervention for the treatment of axillary nerve injuries in adults with brachial plexus injuries.nnnTYPE OF STUDY/LEVEL OF EVIDENCEnTherapeutic III.

Nerve Repair and Nerve Grafting

Direct repair and nerve autografting are primary options in the treatment of upper extremity peripheral nerve injuries. Deciding between these surgical options depends on the mechanism of injury, time since injury, and length of repair defect. Principles of direct repair and nerve autografting are reviewed. Finally, a literature-based review of the outcomes of upper extremity peripheral nerve repair and autografting is provided. Taken together, this article provides relevant and recent data for surgeons regarding patient selection, technique selection, surgical technique, surgical outcomes, and prognostic factors that will aid surgeons treating patients with upper extremity peripheral nerve injuries.

Preoperative Donor Nerve Electromyography as a Predictor of Nerve Transfer Outcomes

PURPOSEnWe hypothesized that health of the donor nerve and corresponding muscle, as assessed by electromyography (EMG), could predict the outcome of nerve transfer surgery.nnnMETHODSnA retrospective review was performed to investigate outcomes of nerve transfers for elbow flexion and shoulder abduction. Motor strength was graded preoperatively and after a minimum 1-year follow-up. Preoperative EMG results were classified as functionally normal or affected based on motor unit recruitment pattern and correlated with follow-up motor strength and range of motion.nnnRESULTSnForty nerve transfers were identified: 27 were performed for elbow flexion and 13 for shoulder abduction. Overall, the 29 transfers in the normal EMG cohort showed significantly greater postoperative improvement in motor strength (Medical Research Council grade 0.2-4.1) than the 11 transfers in the affected EMG cohort (grade 0.0-3.0). In the shoulder cohort, normal donor nerves resulted in greater strength (grade 4.0 vs. 2.4) and active motion (83° vs. 25°) compared with affected donor nerves. Double fascicular transfers with 2 normal donor nerves demonstrated improved strength compared with double nerve transfers when 1 donor nerve was affected (grade 4.5 vs. 3.2).nnnCONCLUSIONSnOur findings demonstrate that a simple EMG classification that describes the quality of donor nerves can predict outcome as measured by postoperative motor strength and range of motion. Preoperative EMG evaluation should be considered a valuable supplementary component of the donor nerve selection process when planning brachial plexus reconstruction.nnnTYPE OF STUDY/LEVEL OF EVIDENCEnPrognostic II.

Current Methods and Biomechanics of Extensor Tendon Repairs

Extensor tendon injuries occur frequently. An in-depth understanding of the intricate anatomy of the extensor mechanism is necessary to guide management. Careful counseling is helpful in ensuring patient compliance and optimal outcomes for nonoperative and surgical treatments. For distal lacerations in Zones II-V, we prefer the running-interlocked horizontal mattress technique. Prolonged immobilization or inadvertent shortening of the extensor mechanism can create the unintended consequence of joint stiffness. While clinical outcomes have improved with modern repairs and rehabilitation, patients should be advised that a slight extensor lag may persist and full flexion may not be possible despite seemingly successful treatment.

Anatomical Study of the Surgical Approaches to the Radial Tunnel

PURPOSEnTo provide a cadaveric analysis of 3 surgical approaches (anterior, anterolateral, posterior) used for decompression of the posterior interosseous nerve within the radial tunnel. The aim of the study was to determine whether the number of compression sites visualized and safely released differed between approaches. We hypothesized that no single approach is adequate for visualization of all key compression sites.nnnMETHODSnThirty fresh-frozen cadaveric specimens were used to perform 10 anterior, 10 anterolateral, and 10 posterior approaches to the radial tunnel. For each approach, key anatomical structures and the 5 documented anatomical sites of nerve compression that were clearly visualized within the surgical exposure were recorded. The portion of the supinator that was directly visualized in each approach was released. A second window was then created to expose the remaining uncut portion of the supinator. Measurements were taken from each specimen.nnnRESULTSnStatistical analysis demonstrated that the anterior and anterolateral approaches were best for visualizing the fibrous bands of the radial head, the leash of Henry, the origin of the extensor carpi radialis brevis, and the arcade of Frohse. The posterior approach was best for visualizing the distal border of the supinator. The relative uncut supinator distance varied with approach. The anterior approach left a larger relative uncut portion than the posterior approach.nnnCONCLUSIONSnNo single approach was adequate for complete visualization and release of all compression points of the radial tunnel. In cases of radial tunnel release, complete visualization of the posterior interosseous nerve compression sites is best achieved through multiple windows.nnnTYPE OF STUDY/LEVEL OF EVIDENCEnTherapeutic IV.

Open Treatment of Acute Scapholunate Instability

Acute treatment of scapholunate instability is important to prevent future complications of dorsal intercalated segment instability and scapholunate advanced collapse. An understanding of the fundamental normal and abnormal mechanics of this problem is vital. Diagnosis in the acute phase is based on clinical and radiographic findings and treatment focuses on primary scapholunate interosseous ligament repair with a reinforcing dorsal capsulodesis. Suture anchor repair with a modified double-dorsal capsulodesis is described. Current data show that open repair is a viable option in the acute setting with most patients demonstrating good to excellent functional, clinical, and radiographic results.

Proximal Migration of Hardware in Patients Undergoing Midcarpal Fusion with Headless Compression Screws

Backgroundu2003Scaphoid excision and limited intercarpal fusion is a common surgical procedure performed for degenerative disorders of the wrist including scapholunate advanced collapse (SLAC) and scaphoid nonunion advanced collapse (SNAC) wrist deformities. Postoperative screw migration is a rare but devastating complication that can result in severe degenerative changes in the radiocarpal joint. Questions/Purposesu2003The purpose of this study is to report on a series of patients who developed proximal migration of their hardware following limited intercarpal fusions with headless compression screws. Patients and Methodsu2003Four patients were identified between 2001 and 2012 who were indicated for and underwent scaphoid excision and midcarpal fusions with headless compression screw fixation and subsequently developed hardware migration with screw protrusion into the radiocarpal joint. Detailed chart review was performed. Resultsu2003Mean age at surgery was 64 years (57-69 years). All patients had the diagnosis of SLAC wrist. Mean time to detection of failure was 6 months (4-8 months). All patients demonstrated radiographic union prior to failure based on plain films. Radiographs revealed screw backout with erosion of the radial lunate facet in all patients. Calculated carpal height ratios demonstrated a drop from an average 44.2% to 39.5% at the time of hardware migration. All four patients underwent hardware removal. One patient was not indicated for any further surgery, and two patients underwent further revision surgery. All three patients reported complete pain relief. One patient refused a salvage procedure and had subsequent persistent pain. Conclusionsu2003This study reports a serious complication of scaphoid excision and midcarpal fusion performed with headless compression screws. We advise surgeons to be aware of this potential complication and consider employing methods to reduce the risk of hardware migration. Additionally, we recommend at least 8 months of clinical and radiographic follow-up postoperatively to enable early intervention if necessary. Level of Evidenceu2003Level IV, therapeutic study.

Scapholunate Advanced Collapse: Nomenclature and Differential Diagnosis

S CAPHOLUNATE ADVANCED COLLAPSE (SLAC) was first described by Watson and Ballet upon identifying common radiographic patterns of arthritis in 210 wrists among 4000 radiographs. They described 3 stages of SLAC: arthritis that involves (1) the articulation between the radial styloid and scaphoid distal pole (Fig. 1), (2) the entire radioscaphoid articulation (Fig. 2), and (3) the capitolunate articulation (Fig. 3). Others have described a fourth stage of radiolunate involvement in 14% to 83% of patients. Despite the universal presence of lunate dorsal tilt (ie, dorsal intercalated segment instability [DISI]), Watson and Ballet observed that the radiolunate joint was always spared arthritic involvement because of its congruence in all rotational postures. Importantly, patients with inflammatory arthritis were excluded from the analysis. However, subsequent authors have suggested that the definition be expanded to include crystalline arthropathy or scaphotrapezium-trapezoidal (STT) arthritis in the SLAC staging paradigm. The classic presenting symptoms of SLAC include wrist pain with activity, loss of motion, swelling, and periscaphoid tenderness. This presentation should prompt a diagnostic evaluation in which other potential causes are ruled out. Wrist arthritis may develop secondary to crystalline arthropathy, inflammatory arthritis, STT arthritis, or scaphoid nonunion. Hand surgeons must distinguish between these diagnoses given their differing etiologies and natural histories, to provide appropriate treatment. History, physical examination, and radiographs are generally sufficient for

Association of lesions of the scapholunate interval with arthroscopic grading of scapholunate instability via the geissler classification.

PURPOSEnTo determine whether specific anatomic lesions of the scapholunate supporting structures are associated with the grades of scapholunate instability according to the Geissler classification.nnnMETHODSnSix fresh frozen cadaveric limbs underwent serial arthroscopic sectioning of the scapholunate supporting ligaments. To simulate a progressive scapholunate injury based on the current literature, sectioning occurred as follows: volar scapholunate interosseous ligament (SLIL), membranous SLIL, dorsal SLIL, radioscaphocapitate, long radiolunate, dorsal radiocarpal, dorsal intercarpal, and scaphotrapeziotrapezoid ligaments. We performed arthroscopic examination of the radiocarpal and midcarpal joints after each ligamentous sectioning and recorded the appearance of the scapholunate interval.nnnRESULTSnThere was a progressive increase in Geissler grade with sequential sectioning of the scapholunate supporting ligaments. In all specimens, Geissler grade 2 injury was associated with sectioning of intrinsic ligaments only. Geissler grade 3 injury first appeared with sectioning through the dorsal SLIL and continued through sectioning of the volar extrinsic ligaments. Geissler grade 4 injury did not occur until the dorsal extrinsic ligaments were sectioned. Statistical analysis indicated a linear relationship between ligament sectioned and Geissler grade, with deeper sections associated with a higher Geissler grade.nnnCONCLUSIONSnIn this cadaveric model, arthroscopically determined Geissler grade was associated with specific anatomic lesions of the scapholunate supporting ligaments. Sequential sectioning of the ligaments showed a progressive increase in Geissler grade.nnnCLINICAL RELEVANCEnKnowledge of the association of Geissler grade with pathoanatomy may aid the surgeon in deciding which reconstructive method is best.