Nelson S. Saldua

The Effect of Drilling Angle on Posterior Interosseous Nerve Safety During Open and Endoscopic Anterior Single-Incision Repair of the Distal Biceps Tendon

PURPOSE The purpose of this study was to define a safe trajectory with regard to iatrogenic posterior interosseous nerve (PIN) injury when drilling the bicipital tuberosity for EndoButton repair (Smith & Nephew Endoscopy, Andover, MA) of distal biceps tendon ruptures. METHODS Ten cadaveric forearms were dissected. The bicipital tuberosity was exposed and the biceps tendon detached. The supinator and PIN were exposed dorsally. A K-wire was drilled perpendicular to the surface of the tuberosity. By use of digital calipers, the distance from the exit point of this wire to the PIN was measured. The length of the bone tunnel was also measured. This wire was removed, and a second was drilled from the same starting point but directed 30 degrees ulnarly. Measurements were repeated. A Wilcoxon signed rank test was used to compare the distances of the K-wire to the PIN and the tunnel lengths for both trajectories. RESULTS With the perpendicular wire, the mean distance to the PIN was 11.1 mm. When directed 30 degrees ulnarly, the mean distance was 16.4 mm. The difference was significant (P < .001). The mean bone tunnel lengths for the 2 trajectories were 17.8 mm and 18.1 mm; this was not found to be significant (P = .508). CONCLUSIONS When drilling the bicipital tuberosity, we advocate starting at a center-center position on the face of the tuberosity, holding the forearm in maximum supination, and aiming 30 degrees ulnarly to decrease the risk to the PIN. This trajectory does not decrease the bone tunnel length available for implants. CLINICAL RELEVANCE This cadaveric anatomic study establishes safety from iatrogenic PIN injury during drilling of the bicipital tuberosity for the purpose of open or endoscopic EndoButton repair of distal biceps tendon ruptures.

Acetabular Retroversion in Military Recruits with Femoral Neck Stress Fractures

Acetabular retroversion (AR) alters load distribution across the hip and is more prevalent in pathologic conditions involving the hip. We hypothesized the abnormal orientation and mechanical changes may predispose certain individuals to stress injuries of the femoral neck. We retrospectively reviewed the anteroposterior (AP) pelvic radiographs of 54 patients (108 hips) treated for a femoral neck stress fracture (FNSF) and compared these radiographs with those for a control group of patients with normal pelvic radiographs. We determined presence of a crossover sign (COS), femoral neck abnormalities, and neck shaft angle. The prevalence of a positive COS was greater in patients with stress fractures than in the control subjects (31 of 54 [57%] versus 17 of 54 [31%], respectively) and higher than for control subjects reported in the literature. Thirteen patients had radiographic changes of the femoral neck consistent with femoroacetabular impingement (FAI). These radiographic abnormalities were seen more commonly in retroverted hips. A greater incidence of AR was noted in patients with FNSF. Potential implications include more aggressive screening of military recruits with AR and the new onset of hip pain. Finally, we present an algorithm we use to diagnose and treat these relatively rare FNSFs.Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

THERMAL NECROSIS COMPLICATING REAMED INTRAMEDULLARY NAILING OF A CLOSED TIBIAL DIAPHYSIS FRACTURE: A CASE REPORT

A case report of thermal necrosis of the tibia after reamed intramedullary nailing is presented. Given the consequences of this complication, the proper use of reaming technique and equipment is emphasized.

Plantar Flexion Influences Radiographic Measurements of the Ankle Mortise

BACKGROUND The treatment of ankle fractures often depends on the integrity of the deltoid ligament. Diagnosis of a deltoid ligament tear depends on the measurement of the medial clear space. We sought to evaluate the impact of ankle plantar flexion on the medial clear space. METHODS Mortise radiographs were made for twenty-five healthy volunteers, with the ankle in four positions of plantar flexion (0 degrees, 15 degrees, 30 degrees, and 45 degrees). Four observers measured the medial clear space and the superior clear space on each radiograph. The mean medial clear space at 0 degrees was defined as the control, and the deviation of the medial clear space from the control value was calculated at 15 degrees, 30 degrees, and 45 degrees of plantar flexion. The ratio of the medial clear space to the superior clear space was determined on all radiographs, and ratios that were false-positive for a deltoid ligament injury were identified. RESULTS Fourteen male and eleven female volunteers were evaluated. The average increase in the medial clear space when ankle plantar flexion was increased from 0 degrees to 45 degrees was 0.38 mm (95% confidence interval, 0.18 to 0.58 mm). This increase was significant (p = 0.005). The average increase in the medial clear space was 0.04 mm when ankle plantar flexion was increased from 0 degrees to 15 degrees and 0.22 mm when it was increased from 0 degrees to 30 degrees. Neither of these changes was significant (p = 0.99 and 0.20). The prevalence of false-positive findings of deltoid injury based on the ratio of the medial clear space to the superior clear space increased as ankle plantar flexion increased, but this increase did not reach significance in our study group (p = 0.18). CONCLUSIONS Plantar flexion of the ankle produces changes in radiographic measurements of the medial clear space. The potential for false-positive findings of deltoid disruption increases with increasing ankle plantar flexion.

Chondromyxoid Fibroma of the Lumbar Spine in a Pediatric Patient

Chondromyxoid fibroma is a rare nonmalignancy that comprises <1% of all bone tumors. It typically presents with pain, swelling, and tenderness to palpation. The lesion has a predilection for the metaphysis of long bones of the lower extremity, most commonly in the proximal tibial metaphysis. Patients often present in their second or third decade of life, although some reports have included a younger average age. Sporadic reports of chondromyxoid fibroma in the spine are found in the literature. This article presents the second case of a chondromyxoid fibroma of the lumbar spine in a pediatric patient, along with a literature review with emphasis on recurrence rates and malignant transformation.

Thoracic Fracture through a Prior Instrumented Arthrodesis in a Patient with Ankylosing Spondylitis without Hardware Loosening: A Case Report

The objective of this article is to report a case of a patient with ankylosing spondylitis who sustained a fracture through a prior solid arthrodesis without loosening or changing posterior instrumentation. There have been few cases reported of a patient with ankylosing spondylitis suffering a fracture through a prior instrumented arthrodesis. None have noted the instrumentation remaining intact with the fracture through the middle of the construct. The surgeon must be aware of this possibility to avoid spinal instability that may lead to a neurological deficit. We retrospectively reviewed the case. A review of the literature was performed through a PubMed search. A patient was found to have a fracture within a prior construct despite the presence of a posterior instrumentation. The mechanism of failure was a three-column spine fracture with “bending” of the rods. This patient was treated with a revision posterior/anterior instrumentation and fusion with placement of larger-diameter rods for added stiffness. Fractures through a prior instrumented arthrodesis are rare but still can occur in the ankylosing spondylitis patient. Given the higher risk of epidural hematoma and neurological compromise in this patient population, the surgeon must keep this on the differential diagnosis when treating patients with a prior instrumented arthrodesis.

Adjacent Segment Disease: Natural History of Lumbar Degeneration or Consequence of Fusion?

Adjacent segment disease is a concern following surgical intervention in the lumbar spine. This chapter provides an overview of adjacent segment degeneration and disease and reviews the current literature regarding its etiology. There is considerable debate as to whether adjacent segment disease is a result of natural history of degeneration of the lumbar spine or secondary to changes induced by surgical intervention. Based upon the best available evidence, it is hypothesized that adjacent segment disease is a multifactorial process. Underlying genetic predisposition and environmental factors play an important role. It is also likely that changes in lumbar motion and kinematics following fusion procedures also increase risk of its development. Advances in motion-sparing technologies for the lumbar spine may decrease incidence of adjacent segment disease, but further research is imperative.

Complications: Neurological Injury

One of the most disturbing spinal surgical “complications” is that of neurological injury. Injury to the spinal cord and nerve roots may occur in any stage of a procedure from patient positioning to wound closure and can vary from a nerve root paralysis or dysesthesia to spinal cord damage. In this chapter, the mechanism by which the neurological injury occurs and potential methods of preventing iatrogenic spinal cord injury are discussed and reviewed.

Cervical instability presenting as thoracic pain: Case report and literature review

Abstract Study design Case report. Objective To report a case of cervical instability from an os odontoideum that presented as posterior thoracic pain and to present a review of the literature. Background Thoracic posterior paraspinal spasms and pain are common chief complaints in individuals with spinal abnormalities. Methods A 19-year-old man presented with posterior thoracic pain for nearly 1 year following a college sports-related injury (lacrosse). Computed tomography and magnetic resonance imaging did not reveal any significant thoracic or lumbar spinal cord or nerve root pathology, but did reveal an incidental finding of an os odontoideum. Results Surgical stabilization of the atlantoaxial instability resulting from the os odontoideum resulted in complete resolution of the patients thoracic pain. Conclusions Thoracic back pain without a clear thoracic spine etiology warrants further workup to rule out the possibility of spinal instability.