III.

Study Design:Retrospective review.Objectives:To evaluate the rate of nonoperative treatment failure for cervical facet fractures while secondarily validating computed tomography–based criteria proposed by Spector et al for identifying risk of failure of nonoperative management.Methods:Single-level or multilevel unilateral cervical facet fractures from 2007 to 2014 were included. Exclusion criteria included spondylolisthesis, dislocated or perched facets, bilateral facet fractures at the same level, floating lateral mass, thoracic or lumbar spine injuries, or spinal cord injury. Patients were placed into 3 groups for evaluation: immediate operative management, successful nonoperative management, and failed nonoperative treatment requiring surgical intervention.Results:Eighty-eight patients (106 facets) were included. Twenty-one patients underwent operative treatment with anterior cervical discectomy and fusion or posterior spinal instrumentation and fusion without any failures. Sixty-seven of these patients were treated nonoperatively with either a hard collar (n = 62) or halo vest (n = 5). Eleven patients failed nonoperative treatment (16.4%), all with an absolute fracture height of at least 1 cm and 40% involvement of the absolute height of the lateral mass. Of the 56 patients successfully treated through nonoperative measures, 8 (14.3%) had fracture measurements exceeding both operative parameters.Conclusion:We conclude that it is safe and appropriate for patients with unilateral cervical facet fractures to receive a trial period of nonoperative management. However, patients who weigh over 100 kg, have comminuted fractures, or have radiographic measurements outside of the proposed computed tomography criteria for nonoperative treatment should be educated on the risks of treatment failure.

Background: The infrapatellar branch of the saphenous nerve (IPBSN) is a purely sensory nerve innervating the anteromedial aspect of the knee and anteroinferior knee joint capsule. Total knee arthroplasty (TKA) is commonly used to treat end-stage arthritis, but the IPBSN is often injured and results in numbness around the anteromedial knee. The aim of this cadaveric study was to describe the course and variability of the IPBSN and to assess whether it is possible to preserve during a standard midline surgical approach in TKA. Methods: Ten fresh-frozen cadaver legs were dissected using a midline approach to the knee. Skin and subcutaneous flap were reflected to expose both the saphenous nerve and its branches. The branches of the IPBSN were identified, and their vertical distances above the tibial tuberosity (TB) were recorded: TB to inferior branch, to middle branch, and to superior branch. Results: There were 10 left-sided specimens (6 female, 4 male) with a mean age of 79.9 AE 9.8 years. 8 (80%) specimens had 2 branches of IPBSN while 2 (20%) specimens had 3 branches. The average distance from TB to the inferior branch was 16.8 AE 8.3 mm (3.0-28.0); middle branch, 24.0 AE 1.4 mm (23.0-24.9); and superior, 45.9 AE 7.7 mm (32.0-54.5). Conclusion: Our cadaveric study found no consistent way to preserve the IPBSN using a standard midline approach in TKA. It is important to provide proper patient education on this complication, and surgeons should be aware of approximate locations and variations of IPBSN while performing other knee procedures.

Our goal was to develop a novel technique for inducing Achilles tendinopathy in animal models which more accurately represents the progressive histological and biomechanical characteristic of chronic Achilles tendinopathy in humans. In this animal research study, forty-five rabbits were randomly assigned to three groups and given bilateral Achilles injections. Low dose (LD group) (n = 18) underwent a novel technique with three low-dose (0.1mg) injections of collagenase that were separated by two weeks, the high dose group (HD) (n = 18) underwent traditional single high-dose (0.3mg) injections, and the third group were controls (n = 9). Six rabbits were sacrificed from each experimental group (LD and HD) at 10, 12 and 16 weeks. Control animals were sacrificed after 16 weeks. Histological and biomechanical properties were then compared in all three groups. At 10 weeks, Bonar score and tendon cross sectional area was highest in HD group, with impaired biomechanical properties compared to LD group. At 12 weeks, Bonar score was higher in LD group, with similar biomechanical findings when compared to HD group. After 16 weeks, Bonar score was significantly increased for both LD group (11,8±2,28) and HD group (5,6±2,51), when compared to controls (2±0,76). LD group showed more pronounced histological and biomechanical findings, including cross sectional area of the tendon, Young’s modulus, yield stress and ultimate tensile strength. In conclusion, Achilles tendinopathy in animal models that were induced by serial injections of low-dose collagenase showed more pronounced histological and biomechanical findings after 16 weeks than traditional techniques, mimicking better the progressive and chronic characteristic of the tendinopathy in humans.

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