Adam M. Caputo

In Vivo Kinematics of the Tibiotalar Joint After Lateral Ankle Instability

Background Previous studies have suggested that injury to the anterior talofibular ligament (ATFL) may be linked to altered kinematics and the development of osteoarthritis of the ankle joint. However, the effects of ATFL injury on the in vivo kinematics of the ankle joint are unclear. Hypothesis Based on the orientation of the ATFL fibers, ATFL deficiency leads to increased anterior translation and increased internal rotation of the talus relative to the tibia. Study Design Descriptive laboratory study. Methods The ankles of 9 patients with unilateral ATFL injuries were compared as they stepped onto a level surface. Kinematic measurements were made as a function of increasing load. With use of magnetic resonance imaging and orthogonal fluoroscopy, the in vivo kinematics of the tibiotalar joint were measured in the ATFL-deficient and intact ankles of the same individuals. Results A statistically significant increase in internal rotation, anterior translation, and superior translation of the talus was measured in ATFL-deficient ankles, as compared with the intact contralateral controls. For example, at 100% body weight, ATFL-deficient ankles demonstrated an increase of 0.9 ± 0.5 mm in anterior translation (P = .008), an increase of 5.7° ± 3.6° in internal rotation (P = .008), and a slight increase of 0.2 ± 0.2 mm in the superior translation (P = .02) relative to the intact contralateral ankles. Conclusion Deficiency of the ATFL increases anterior translation, internal rotation, and superior translation of the talus. Clinical Relevance Altered kinematics may contribute to the degenerative changes observed with chronic lateral ankle instability. These findings might help to explain the degenerative changes frequently observed on the medial talus in patients with chronic ATFL insufficiency and so provide a baseline for improving ankle ligament reconstructions aimed at restoring normal joint motion.

Intermediate to Long-Term Outcomes of the STAR Total Ankle Replacement: The Patient Perspective

BACKGROUND The purpose of the present study was to document the patient self-reported improvements in quality of life, function, and overall impairment scores, as well as the improvement in the clinically derived outcome scores, following a Scandinavian Total Ankle Replacement (STAR) arthroplasty performed for the treatment of end-stage ankle arthritis. METHODS All patients who underwent a Scandinavian Total Ankle Replacement arthroplasty from July 1998 through February 2008 were prospectively followed and retrospectively reviewed. All surgical procedures were performed by a single surgeon. Preoperatively and at subsequent follow-up visits, patients were assessed with (1) a visual analog scale (VAS) score for pain, (2) the Short Form-36 (SF-36) quality-of-life scale, (3) the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot scale and subscales, (4) the Buechel-Pappas pain and function scores, and (5) the ankle range of motion. Additional measures that were recorded included (1) concomitant surgical procedures during the initial ankle replacement, (2) revision surgery during the follow-up period, and (3) any additional surgical procedures. Revision was defined as failure of either the tibial or the talar metallic component that required removal of a metallic implant for any reason. RESULTS Eighty-two consecutive patients were evaluated. The duration of follow-up ranged from twenty-four to 108 months (mean, sixty-one months; median, sixty months). During the follow-up period, three patients died and six patients moved out of the region. The latter six patients were followed by another surgeon group, and their data were included. Eight patients were lost to follow-up after twelve months. There were significant improvements in all outcome categories between the preoperative and postoperative evaluations. The most compelling finding of the present study involved the marked improvement in terms of the self-reported measures of impairments, quality of life, pain, and function. CONCLUSIONS Total ankle arthroplasty with the Scandinavian Total Ankle Replacement prosthesis was associated with significant improvements in terms of pain, function, and quality of life after intermediate to long-term follow-up.

In vivo cartilage contact strains in patients with lateral ankle instability

Damage to the anterior talofibular ligament (ATFL) and cacaneofibular ligament (CFL) during an ankle sprain may be linked to the development of osteoarthritis. Although altered tibiotalar kinematics have been demonstrated, the effects of lateral ankle instability (LAI) on in vivo cartilage strains have not been described. We hypothesized that peak cartilage strains increase, and the location is shifted in patients with ATFL injuries. We used 3-D MRI models and biplanar fluoroscopy to evaluate in vivo cartilage contact strains in seven patients with unilateral LAI. Subjects had chronic unilateral ATFL injury or combined ATFL and CFL injury, and were evaluated with increasing load while stepping onto a force plate. Peak cartilage strain and the location of the peak strain were measured using the contralateral normal ankle as a control. Ankles with LAI demonstrated significantly increased peak strain when compared with ATFL-intact controls. For example, at 100% body weight, peak strain was 29+/-8% on the injured side compared to 21+/-5% on the intact side. The position of peak strain on the injured ankle also showed significant anterior translation and medial translation. At 100% body weight, the location of peak strain in the injured ankle translated anteriorly by 15.5+/-7.1mm and medially by 12.9+/-4.3mm relative to the intact ankle. These changes correspond to the region of clinically observed osteoarthritis. Chronic LAI, therefore, may contribute to the development of tibiotalar cartilage degeneration due to altered cartilage strains.

Clinical Outcomes of Extreme Lateral Interbody Fusion in the Treatment of Adult Degenerative Scoliosis

Introduction. The use of extreme lateral interbody fusion (XLIF) and other lateral access surgery is rapidly increasing in popularity. However, limited data is available regarding its use in scoliosis surgery. The objective of this study was to evaluate the clinical outcomes of adults with degenerative lumbar scoliosis treated with XLIF. Methods. Thirty consecutive patients with adult degenerative scoliosis treated by a single surgeon at a major academic institution were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Validated clinical outcome scores were obtained on patients preoperatively and at most recent follow-up. Complications were recorded. Results. The study group demonstrated improvement in multiple clinical outcome scores. Oswestry Disability Index scores improved from 24.8 to 19.0 (P < 0.001). Short Form-12 scores improved, although the change was not significant. Visual analog scores for back pain decreased from 6.8 to 4.6 (P < 0.001) while scores for leg pain decreased from 5.4 to 2.8 (P < 0.001). A total of six minor complications (20%) were recorded, and two patients (6.7%) required additional surgery. Conclusions. Based on the significant improvement in validated clinical outcome scores, XLIF is effective in the treatment of adult degenerative scoliosis.

Extreme lateral interbody fusion for the treatment of adult degenerative scoliosis

Extreme lateral interbody fusion (XLIF; NuVasive Inc., San Diego, CA, USA) is a minimally invasive lateral transpsoas approach to the thoracolumbar spine. Though the procedure is rapidly increasing in popularity, limited data is available regarding its use in deformity surgery. We aimed to evaluate radiographic correction using XLIF in adults with degenerative lumbar scoliosis. Thirty consecutive patients were followed for an average of 14.3 months. Interbody fusion was completed using the XLIF technique with supplemental posterior instrumentation. Plain radiographs were obtained on all patients preoperatively, postoperatively, and at most recent follow-up. Plain radiographic measurements of coronal Cobb angle, apical vertebral translation, segmental lordosis, global lordosis, disc height, neuroforaminal height and neuroforaminal width were made at each time point. CT scans were obtained for all patients 1 year after surgery to evaluate for fusion. There was significant improvement in multiple radiographic parameters from preoperative to postoperative. Cobb angle corrected 72.3%, apical vertebral translation corrected 59.7%, neuroforaminal height increased 80.3%, neuroforaminal width increased 7.4%, and disc height increased 116.7%. Segmental lordosis at L4-L5 increased 14.1% and global lordosis increased 11.5%. There was no significant loss of correction from postoperative to most recent follow-up. There was an 11.8% pseudoarthrosis rate at levels treated with XLIF. Complications included lateral incisional hernia (n=1), rupture of anterior longitudinal ligament (n=2), wound breakdown (n=2), cardiac instability (n=1), pedicle fracture (n=1), and nonunion requiring revision (n=1). XLIF significantly improves coronal plane deformity in patients with adult degenerative scoliosis. XLIF has the ability to correct sagittal plane deformity, although it is most effective at lower lumbar levels.

Risk factors for infection after orthopaedic spine surgery at a high-volume institution.

Surgical site infections are associated with increased morbidity, mortality, and resource utilization. To identify risk factors for infection, the authors reviewed all orthopaedic spine operations at Duke University Medical Center from 2005 to 2010. Of the 3138 patients treated during the study period, 115 developed a surgical site infection (3.7%). Demographics, comorbidities, and perioperative blood glucose levels were analyzed in the infected and uninfected cohorts. History of myocardial infarction, congestive heart failure, renal disease, pneumonia, urinary tract infection, and diabetes mellitus (DM) were associated with a higher risk of infection. Notably, a diagnosis of DM nearly doubled the risk of infection. Even in patients without DM, perioperative blood glucose levels greater than 140 mg/dL doubled the risk of infection. The authors propose that strict blood glucose control in both DM and non-DM patients may significantly reduce the risk of infection after spinal surgery.

Lumbar facet cyst resolution following anterior interbody fusion.

Facet cysts are a relatively common source of neural compression in the lumbar spine. Open decompression and fusion are frequently used to treat the stenosis and instability associated with this pathology. Recently, anterior lumbar interbody fusion (ALIF) has increased in popularity for the treatment of lumbar degenerative conditions. ALIF may achieve indirect decompression of the neural elements with less surgical morbidity than conventional open approaches. To date, there are no published reports describing the use of indirect decompression or interbody fusion for the treatment of facet cysts. We report a patient who developed an L4-L5 facet cyst secondary to degenerative changes and spondylolisthesis. ALIF with posterior instrumentation was used to address his condition. Six months after surgery, the patient had complete resolution of his symptoms. MRI revealed complete resolution of the facet cyst. This patient provides previously unreported evidence that interbody fusion alone may result in facet cyst resolution. Clinical studies are needed to evaluate if interbody fusion can consistently relieve the symptoms associated with facet cysts without the use of direct decompression.

Spinal Epidural Hematoma Following Epidural Steroid Injection in a Patient Treated with Dabigatran

Lumbar epidural steroid injections are commonly employed in the treatment of degenerative lumbar conditions. The procedure is generally accepted as safe, and few complications have been reported in the literature. An exceedingly rare complication of epidural steroid injection is a spinal epidural hematoma. Although millions of epidural steroid injections have been completed since 19601-3, to our knowledge, there have been no more than fifteen reported cases of epidural hematoma related to epidural steroid injections4-16. A review of these reports reveals that nearly all of the patients involved were taking anticoagulants near the time of injection. In October 2010, the U.S. Food and Drug Administration (FDA) approved the use of a novel anticoagulant called dabigatran (Pradaxa; Boehringer Ingelheim Pharmaceuticals, Ridgefield, Connecticut) for the prevention of stroke in patients with atrial fibrillation. In Europe and Canada, the drug also has been approved for the prevention of thromboembolism in patients undergoing total joint arthroplasty. Dabigatran has experienced a rapid increase in popularity in the orthopaedic community because it has several benefits over enoxaparin and warfarin. Unlike enoxaparin, dabigatran is administered orally. Unlike warfarin, dabigatran has minimal monitoring requirements and few drug-drug and drug-food interactions, and it becomes therapeutic within hours instead of days17. Currently, to the best of our knowledge, there are no known cases in the literature of dabigatran-associated complications after epidural steroid injections. Recent clinical trials involving over 20,000 patients treated with dabigatran did not identify a single case of spinal epidural hematoma17,18. The patient was informed that data concerning the case would be submitted for publicaton, and he provided consent. ### History A seventy-year-old man presented with ongoing symptoms of lower back pain and bilateral leg pain for four months. Neurological examination revealed full motor strength in the …

Distant Harrington rod migration 35 years after implantation

Harrington rods have been successfully implanted in thousands of patients for the correction of scoliotic deformity since the 1950s. An exceedingly rare complication of Harrington rod placement is loosening with resultant migration. The authors present a 50-year-old woman who had a single Harrington rod placed when she was 15 years old. Thirty-five years later, she presented with acute sensory changes in her lower extremities. Imaging revealed rod failure and migration of the hardware distally, resulting in penetration of the wall of the rectum. Due to the unique anatomical position of the migrated hardware, sigmoidoscopy was used to directly visualize and remove the rod. The patient ultimately made a full recovery. Rod migration is an exceedingly rare complication that has been described only a few times since the introduction of Harrington rods over 60 years ago. The case herein is particularly unique given the extensive period of time that passed before migration (35 years) and the use of sigmoidoscopy for hardware removal.