APRIL 2008 VOLUME XXXVII NUMBER 4 pISSN:1078-4519 eISSN:1934-3418

E-PUBLISHING

59	Guest Editorial—Peer-Reviewed Articles in Spine Surgery Kingsley R. Chin, MD Kingsley R. Chin, MD, is Founder, Institute for Minimally Invasive Spine Surgery (IMIS), www.IMISsurgery.com. Abstract not available. Am J Orthop. 2008;37(4):E59, E91.
60	Measurement of Thoracolumbar Kyphosis After Burst Fracture: Evaluation of Intraobserver, Interobserver, and Variability of 4 Measurement Methods Jerome G. Enad, MD, Joseph B. Slakey, MD, and Patrick S. McNulty, MD CDR Jerome G. Enad, MC, USN, is Assistant Professor of Surgery, Uniformed Services University of the Health Sciences, Bethesda, Maryland. There are various methods for measuring kyphosis after thoracolumbar burst fracture. The reliability and reproducibility of these methods are not well defined. In the study reported here, we examined 4 commonly used measurement methods in order to determine intraobserver variability, interobserver variability, and variability between measurement methods. All 4 methods were found to be accurate and reproducible when used by 4 observers on 2 occasions. One method, in comparison with the others, tended to overestimate degree of kyphosis. Understanding the methods for measuring kyphotic deformity after thoracolumbar burst fracture is essential in making decisions about prognosis and treatment. Am J Orthop. 2008;37(4):E60-E63.
64	Evaluation of Total Disc Arthroplasty: A Canine Model Brett A. Taylor, MD, Gbolahan O. Okubadejo, MD, Alpesh A. Patel, MD, Michael R. Talcott, DVM, Toshii Imamura, MD, PhD, Nianbin Hu, MD, and Bryan W. Cunningham, MSc Brett A. Taylor, MD, is an Orthopaedic Surgeon, Orthopaedic Center of St. Louis, Chesterfield, Missouri. The study reported here was designed to examine the biomechanical and histopathologic properties of total disc arthroplasty (TDA) using a canine model. Thirty-seven dogs were divided into 3 groups (intact spine, fusion, TDA) and sacrificed either at study commencement or at 3 months. Results showed progressive fusion from 0 to 3 months in the fusion group. The TDA group maintained motion throughout this period. No neurologic complications were noted in either group. These results establish the canine as a model for future studies of TDA. Am J Orthop. 2008;37(4):E64-E70.
71	Comparison of Single-Level Cervical Fusion and a Metal-on-Metal Cervical Disc Replacement Device Joseph Riina, MD, Amisha Patel, MS, ATC, LAT, John W. Dietz, MD, Jeffrey S. Hoskins, MD, Terry R. Trammell, MD, and David G. Schwartz, MD Joseph Riina, MD, is Orthopaedic Spine Surgeon, Department of Spine Surgery, Indiana Orthopaedic Hospital, Indianapolis, Indiana. Cervical fusion is the common treatment for cervical disc disease but can cause secondary disorders. The Prestige ST cervical disc prosthesis (Medtronic Sofamor Danek, Memphis, TN) was designed to preserve spinal motion to potentially limit the secondary disorders. In this article, we report 2-year results from a single- center study comparing use of this device with use of anterior cervical discectomy and fusion (ACDF). Nineteen patients were prospectively randomized to receive the device or to undergo ACDF. Twenty-four months after surgery, patients who received the device demonstrated improvement in neck pain, arm pain, and neurologic function. In our cohort, patients who underwent arthroplasty demonstrated greater improvement in neurologic function and neck pain than patients who underwent cervical discectomy and fusion. Am J Orthop. 2008;37(4):E71-E77.
78	Influence of Orthopedic Implant Structure on Adjacent Bone Density and on Stability Fidèle Likibi, PhD, Gilles Chabot, MD, Michel Assad, PhD, and Charles-Hilaire Rivard, MD Fidèle Likibi, PhD, is Senior Scientist, Research Center and Orthopaedic Surgery Department, Ste-Justine Hospital, Montreal, Canada, and Institute of Biomedical Engineering, University of Montreal, Montreal, Canada. We evaluated the ability of a porous metallic interbody fusion implant made with porous nitinol (PNT) to achieve intervertebral fusion and the capacity of stabilization at the implantation site 3, 6, and 12 months after implantation. Sixteen sheep each received 1 PNT implant and 1 titanium (TiAIV) cage at intervertebral lumbar levels L2–L3 and L4–L5; 3 other sheep were used as untreated controls. The TiAIV cage was used as a control implant. After animal sacrifice, computed tomography was used to study peri-implant bone mineral density (BMD), and histologic slices were used to evaluate implant osseointegration. BMD around PNT implants was close to physiological (control value) BMD, whereas BMD around TiAIV cages was usually higher (sclerosis) than physiological BMD. Histologic analysis showed better osseointegration with PNT implants than with TiAIV cages. Sclerosis might result from bone acting to stabilize implants in their implantation sites. Compared with PNT implants, TiAIV cages seemed to be unstable in their implantation sites. For PNT implants, osseointegration was successful, and surrounding BMD was close to physiologic BMD. Am J Orthop. 2008;37(4):E78-E83.
84	Evaluation of Autologous Platelet Concentrate for Intertransverse Process Lumbar Fusion Paul M. Sethi, MD, José J. Miranda, MD, MPH, Sudha Kadiyala, PhD, Tushar Ch. Patel, MD, Manohar Panjabi, PhD, Nancy Troiano, MS, and Gary E. Friedlaender, MD Paul M. Sethi, MD, is Sports Medicine Attending, Orthopedic and Neurological Surgery Specialists, Greenwich, Connecticut. Data on the role of platelet concentrate (PC) in spinal fusion are limited. Using the New Zealand white rabbit model, we compared fusion rates at L5–L6 using 2 different volumes (1.5 cm3, 3.0 cm3) of iliac crest autograft with and without PC (4 groups total, 10 animals in each). PC was collected from donor rabbits and adjusted to a concentration of 1x106 platelets/mL. Bone growth and fusion were evaluated using biomechanical, radiographic, and histologic testing. At 1.5 cm3, autograft alone had a 29% fusion rate, compared with autograft plus PC, which had a 57% fusion rate (P = .06). At 3.0 cm3, the fusion rate approached 90% in both groups. Radiologic fusion had a 70% correlation with biomechanical test results. Huo/Friedlaender scores were 4.3 (SD, 2.9) for 1.5-cm3 autograft alone; 5.0 (SD, 3.5) for 1.5-cm3 autograft plus PC; 4.7 (SD, 2.5) for 3.0-cm3autograft alone; and 7.7 (SD, 0.6) for 3.0-cm3 autograft plus PC. For 1.5-cm3 autograft, a trend toward improvement in biomechanically defined fusion was found when PC was added, which suggests that, when the amount of bone graft is limited, PC may function as a graft extender in posterolateral fusion. At higher volumes of bone graft, no appreciable difference was noted between groups. Although radiography revealed fusion masses, the technique was not useful in identifying pseudarthrosis. On histologic analysis, adding PC seemed to result in more mature bone at both volumes, with the most mature bone in the group with 3.0-cm3 autograft plus PC. Am J Orthop. 2008;37(4):E84-E90.

187	When the Obvious Is Not So Obvious Albert J. Aboulafia, MD, MBA, FACS Albert J. Aboulafia, MD, MBA, FACS, is Co-Director of Sarcoma Services, Cancer Institute at Sinai, Baltimore, Maryland, and Assistant Clinical Professor, Department of Orthopedics, University of Maryland, Baltimore, Maryland. Abstract not available. Am J Orthop. 2008;37(4):187,217.
191	Neurologic Injuries After Total Hip Arthroplasty Gabriel D. Brown, MD, Eli A. Swanson, MD, and Ohannes A. Nercessian, MD Gabriel D. Brown, MD, is Senior Resident, Department of Orthopaedic Surgery, New York Orthopaedic Hospital, Columbia University Medical Center, New York, New York. Neurologic injuries are a potentially devastating complication of total hip arthroplasty (THA). Review of the literature reveals that these injuries are uncommon. The reported incidence ranges from 0.08% to 7.6%. The incidence in primary THA ranges from 0.09% to 3.7% and in revision THA from 0% to 7.6%. Reported etiologies include intraoperative direct nerve injury, significant leg lengthening, improper retractor placement, cement extravasation, cement-related thermal damage, patient positioning, manipulation, and postoperative hematoma. Risk factors include developmental dysplasia of the hip, the female sex, posttraumatic arthritis, and revision surgery. However, no single risk factor has been consistently reported to be significant, and many patients with no known risk factors incur neurologic injuries. Am J Orthop. 2008;37(4):191-197.
198	Talar Osteosarcoma in an Elderly Woman Bradley S. Ellison, MD, Michael Potter, MD, Carl Morrison, MD, DVM, and Joel Mayerson, MD Bradley S. Ellison, MD, is Resident, Department of Orthopedic Surgery, Ohio State University Medical Center, Columbus, Ohio. Abstract not available. Am J Orthop. 2008;37(4):198-203.
204	A Rare Case of Osteosarcoma and Rhabdomyosarcoma at the Same Site 7 Years Apart Jung H. Park, MD, Harish S. Hosalkar, MD, MBMS (Orth), FCPS (Orth), DNB (Orth), Robin E. Miller, MD, and Richard D. Lackman, MD Jung H. Park, MD, is an Orthopaedic Surgery Resident, Temple University, Philadelphia, Pennsylvania. Abstract not available. Am J Orthop. 2008;37(4):204-207.
208	Distal Migration of a Foreign Body (Sago Palm Thorn Fragment) Within the Long-Finger Flexor Tendon Sheath Jianli Bu, MD, Kristi A. Overgaard, BSc, and Steven F. Viegas, MD Jianli Bu, MD, is Orthopaedic Surgeon, Third Military Medical University, Heping (Peace) Hospital, Shijiazhuang, China. Abstract not available. Am J Orthop. 2008;37(4):208-209.
210	Rupture of the Flexor Digitorum Profundus in a Preadolescent Boy Justin B. Hohl, MD, Joshua E. Hyman, MD, and Robert J. Strauch, MD Justin B. Hohl, MD, is Resident, Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, Pittsburgh, Pennsylvania. Abstract not available. Am J Ortho. 2008;37(4):210-212.
214	Segmental Radius and Ulna Fractures With Scaphocapitate Fractures and Bilateral Multiple Epiphyseal Fractures Mohammed Naveed Yasin, MB BCh, MRCSEd, Sumedh Chittaranjan Talwalkar, MB BS, MRCSEd, John James Henderson, MB ChB, FRCSEd, and Stephen Peter Hodgson, MB ChB, FRCS, MD Mohammed Naveed Yasin, MB BCh, MRCSEd, is Senior House Officer, Department of Orthopaedics, Royal Bolton Hospital, Farnworth, Bolton, United Kingdom. Segmental forearm fractures are rare in children, and management is controversial. Epiphyseal injuries further complicate matters. We report the case of a 15-year-old boy who had segmental radius and ulna fractures with a coronal split of a metaphyseal fragment, along with bilateral epiphyseal fractures of the distal radius and ulna as well as ipsilateral scaphocapitate fractures with perilunate dislocation. There was also a contralateral fracture through the radial neck. The patient underwent immediate internal fixation of the forearm fractures and delayed fixation of the scaphocapitate fractures. Results at 12 months showed excellent functional outcome. Am J Orthop. 2008;37(4):214-217.
218	Distal Biceps Brachii Tendon Tear Paul D. Clifford, MD, and Rachel B. Hulen, MD Paul D. Clifford, MD, is Assistant Professor of Clinical Radiology and Chief, Musculoskeletal Section, Department of Radiology, University of Miami Miller School of Medicine, Miami, Florida. Abstract not available. Am J Orthop. 2007;36(4):218-219.

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