A. Noelle Larson

Interposition Arthroplasty with an Achilles Tendon Allograft as a Salvage Procedure for the Elbow

BACKGROUND Interposition arthroplasty is often considered to be a salvage option for the treatment of severe elbow arthritis when conservative treatment has failed and total joint replacement is contraindicated. The present retrospective study summarizes the results of a specific interposition arthroplasty technique for the treatment of inflammatory and posttraumatic arthritis of the elbow. METHODS Between 1996 and 2003, sixty-nine elbows were treated with interposition arthroplasty with an Achilles tendon allograft. Forty-five elbows, including eleven with inflammatory arthritis and thirty-four with posttraumatic arthritis, met our inclusion criteria. The mean patient age was thirty-nine years. The mean duration of clinical follow-up was 6.0 years. Seven patients subsequently underwent revision surgery and were excluded from the analysis. For the thirty-eight remaining patients with surviving allografts, the current Mayo Elbow Performance Score and Disabilities of the Arm, Shoulder and Hand score were obtained and the most recent clinical outcomes and radiographs were reviewed. RESULTS In the group of thirty-eight patients with surviving allografts, the mean flexion-extension arc improved from 51 degrees preoperatively to 97 degrees postoperatively (p < 0.001). The mean Mayo Elbow Performance Score improved from 41 points preoperatively to 65 points postoperatively (p < 0.0001). Thirteen patients had a good or excellent result, fourteen had a fair result, and eleven had a poor result; the remaining seven had a revision. On the basis of the Mayo Elbow Performance Score, twelve patients rated the elbow as somewhat better and nineteen rated the elbow as much better following the interposition procedure. Despite efforts to reconstruct the collateral ligaments, preoperative instability on physical examination (found in eleven patients) was associated with low Mayo Elbow Performance Scores (p = 0.03) and high Disabilities of the Arm, Shoulder and Hand scores (p = 0.006). Four of five patients undergoing reconstruction of both collateral ligaments had a net decrease in the Mayo Elbow Performance Score. CONCLUSIONS We consider interposition elbow arthroplasty to be a salvage procedure as it neither completely eliminates pain nor restores full function. It may be indicated for young active patients with severe inflammatory or posttraumatic arthritis, especially those with limited elbow motion. Furthermore, we do not recommend this procedure when patients present with preoperative instability on physical examination.

Pediatric Pedicle Screw Placement Using Intraoperative Computed Tomography and 3-Dimensional Image-Guided Navigation

Study Design. A retrospective cohort study reporting the use of intraoperative computed tomography (CT) and image-guided navigation system for the placement of pedicle screws in pediatric compared with adult patients. Objective. To evaluate the accuracy of open pedicle screw placement in pediatric patients using intraoperative CT and 3-dimensional (3D) image-guided navigation. Summary of Background Data. Pedicle screws are widely used in children for the correction of spinal deformity. Navigation systems and intraoperative CT are now available as an adjunct to fluoroscopy and anatomic techniques for placing pedicle screws and verifying screw position. Methods. From 2007 to 2010, 984 pedicle screws were placed in a consecutive series cohort of 50 pediatric patients for spinal deformity correction with the use of intraoperative CT (O-arm, Medtronic, Inc, Louisville, CO) and a computerized navigation system (Stealth, Medtronic, Inc, Louisville, CO). The primary outcome measure for this study is redirection or removal of screw on the basis of the intraoperative CT imaging. During the study period, 1511 screws were placed in adult patients using the same image guidance system. Results. A total of 984 pedicle screws were implanted using real-time navigation, with a mean of 20 screws per patient (range: 2–34). On the basis of intraoperative CT, 35 screws (3.6%) were revised (27 redirected and 8 removed), representing a 96.4% accuracy rate. No patients returned to the operating room because of screw malposition. Of the 1511 screws placed in adult patients, 28 (1.8%) were revised intraoperatively for malposition on CT imaging, for an overall 98.2% accuracy rate. Screw revision thus was more common in the pediatric population (P = 0.008). However, the pediatric screw accuracy rate is significantly higher than the findings from a recent meta-analysis of predominantly nonnavigated screws in children, reporting a 94.9% accuracy rate (P = 0.03). Conclusion. We report 96.4% accuracy in pediatric pedicle screw placement using intraoperative CT and a 3D navigation system. This is similar to other reports and has better accuracy than a recent meta-analysis of nonnavigated screws in children.

A prospective multicenter study of Legg-Calvé-Perthes disease: functional and radiographic outcomes of nonoperative treatment at a mean follow-up of twenty years.

BACKGROUND Long-term studies have indicated good outcomes for most patients with Legg-Calvé-Perthes disease. However, clinical experience suggests that less favorable outcomes are common. We sought to prospectively document pain and function in a cohort of adults who had previously been treated nonoperatively for Legg-Calvé-Perthes disease. METHODS Patients in our region with Legg-Calvé-Perthes disease were enrolled between 1984 and 1991 as part of a multicenter prospective trial and were treated with hip range-of-motion exercises or bracing. Patients returned for physical examination, radiographs, and completion of outcome measures including the Nonarthritic Hip Score (NAHS) and the Iowa Hip Score (IHS). RESULTS Fifty-six patients (fifty-eight hips) were examined at a mean of 20.4 years (range, 16.3 to 24.5 years) after enrollment. The mean NAHS was 79 (range, 35 to 100), and the mean IHS was 74 (range, 43 to 100). Three patients had required hip arthroplasty and one patient had required a pelvic osteotomy. Fourteen (26%) of the remaining hips had no hip osteoarthritis, sixteen (30%) had mild osteoarthritis (Tönnis grade 1), and twenty-four (44%) had moderate or severe osteoarthritic changes on radiographs (grade 2 or 3). Femoroacetabular impingement indicated by physical examination was associated with pain and with poorer outcomes on the IHS and the NAHS (p = 0.0004, 0.0014, and 0.0007, respectively). The Stulberg classification was significantly associated with impingement on physical examination (p = 0.0495), the NAHS (p = 0.003), and the Tönnis grade (p = 0.012). Multivariate logistic regression showed that only the Stulberg classification was significantly associated with the NAHS (p = 0.0032); the odds ratio for a Stulberg type of I or II compared with IV or V in patients with a fair or poor NAHS was 0.101 (95% confidence interval, 0.018 to 0.573). CONCLUSIONS Pain, arthritis, and ongoing hip dysfunction are common in patients with Legg-Calvé-Perthes disease that was treated nonoperatively. Hips rated as Stulberg type III or IV more frequently had poor or fair outcomes on the IHS and NAHS (61% and 72% for type III and 77% and 60% for type IV). Patients with a lateral pillar type of B, B/C, or C frequently had pain and radiographic evidence of osteoarthritis. Clinical signs of femoroacetabular impingement were associated with pain and with lower functional scores. This prospective study establishes a modern benchmark for outcomes following nonoperative, weight-bearing treatment of Legg-Calvé-Perthes disease.

Outcomes of slipped capital femoral epiphysis treated with in situ pinning.

Background: Previous long-term studies have shown good outcomes for most patients after in situ pinning of slipped capital femoral epiphyses (SCFE). However, concern is growing about the effects of leaving the epiphysis in a nonanatomic position. We undertook a retrospective study to carefully document patient-reported outcomes and need for additional surgery after in situ pinning of SCFE. Further, we sought to determine the risk factors for persistent pain and dysfunction after in situ pinning. Methods: Between 1965 and 2005, 146 patients (176 hips) with SCFE underwent in situ pinning at a tertiary referral center. Medical records and radiographs were reviewed for slip characteristics and need for subsequent surgery. Patient-reported outcome measures were collected by mailed survey. Mean follow-up was 16 years (range, 2 to 43 y). Results: Twenty-one hips (12%) underwent reconstructive surgery for persistent symptoms, including femoral osteotomy (11), surgical hip dislocation (2), and total hip arthroplasty (8). Mild slips, as well as moderate and severe slips, were treated with reconstructive surgery, including total hip arthroplasty. Of the remaining hips, 33% were painful with a mean overall visual analog score of 2.4 (range, 0 to 10). Mean outcome scores were as follows: Harris Hip Score 90 (max. 100); Hip Dysfunction Osteoarthritis Outcome score 411 (max. 500); UCLA Activity Score 8 (max. 10); and Marx Activity Score 5 (max. 16). Conclusions: Reconstructive surgery was performed in 12% of hips. Patients with mild, moderate, and severe slips underwent arthroplasty for degenerative changes. Persistent mild pain was common in one third of patients treated with in situ pinning. Level of Evidence: Level IV, therapeutic study, case series.

Epigenetic control of skeletal development by the histone methyltransferase Ezh2

Background: Osteogenic differentiation is initiated by transcriptional and post-transcriptional epigenetic mechanisms. Results: Inhibition of H3K27 methyltransferase EZH2 enhances osteogenic commitment of human mesenchymal progenitors, and its depletion in mouse mesenchymal cells causes multiple skeletal abnormalities. Conclusion: EZH2 is required for skeletal patterning and bone formation. Significance: EZH2-dependent epigenetic mechanisms control osteogenesis both in vitro and in vivo. Epigenetic control of gene expression is critical for normal fetal development. However, chromatin-related mechanisms that activate bone-specific programs during osteogenesis have remained underexplored. Therefore, we investigated the expression profiles of a large cohort of epigenetic regulators (>300) during osteogenic differentiation of human mesenchymal cells derived from the stromal vascular fraction of adipose tissue (AMSCs). Molecular analyses establish that the polycomb group protein EZH2 (enhancer of zeste homolog 2) is down-regulated during osteoblastic differentiation of AMSCs. Chemical inhibitor and siRNA knockdown studies show that EZH2, a histone methyltransferase that catalyzes trimethylation of histone 3 lysine 27 (H3K27me3), suppresses osteogenic differentiation. Blocking EZH2 activity promotes osteoblast differentiation and suppresses adipogenic differentiation of AMSCs. High throughput RNA sequence (mRNASeq) analysis reveals that EZH2 inhibition stimulates cell cycle inhibitory proteins and enhances the production of extracellular matrix proteins. Conditional genetic loss of Ezh2 in uncommitted mesenchymal cells (Prrx1-Cre) results in multiple defects in skeletal patterning and bone formation, including shortened forelimbs, craniosynostosis, and clinodactyly. Histological analysis and mRNASeq profiling suggest that these effects are attributable to growth plate abnormalities and premature cranial suture closure because of precocious maturation of osteoblasts. We conclude that the epigenetic activity of EZH2 is required for skeletal patterning and development, but EZH2 expression declines during terminal osteoblast differentiation and matrix production.

The accuracy of navigation and 3D image-guided placement for the placement of pedicle screws in congenital spine deformity.

Background: Treatment of congenital spine deformity has high surgical risk due to abnormal anatomy and dysmorphic pedicles. We hypothesized that an image-guided navigation system would result in a low rate of screw revision due to malposition. Methods: From 2007 to 2010, 142 screws were placed in 14 consecutive patients with congenital spine deformity using an intraoperative computer tomography (CT) (O-arm) and image-guided navigation system (Stealth). Mean age was 8.8 years (range, 1 to 18 y). Deformities included scoliosis (12), kyphosis (1), and spinal dysgenesis (1). Screws were placed from T2 to S1. An intraoperative CT verified screw position. Need for intraoperative screw revision is the primary outcome measure. Results: Of the 142 screws placed, 1 required revision intraoperatively due to malposition (99.3% screw accuracy rate). The screw was at L3 and was successfully redirected. There were no complications due to screw malposition. This navigated congenital screw accuracy rate (99.3%) is higher than the 94.9% accuracy rate reported for non-navigated screws in all children undergoing pedicle screw fixation in a recent systematic literature review and higher than the reported 96.4% accuracy rate for navigated pedicle screws in children. Kosmopoulos and colleagues found a lower accuracy rate (86.6%) in adult non-navigated screws (P<0.0001) and adult navigated screws (93.7%). Of note, 9 pedicles were noted on navigation to be absent. Despite the goal of bilateral screw placement at each fusion level, 31 of 173 pedicles were left unfilled due to technical impossibility based on intraoperative CT imaging. This represents an 18% screw dropout rate. Conclusions: CT-guided navigation resulted in the successful placement of 142 pedicle screws in patients with congenital deformity and altered anatomy, which represents a 99.3% screw accuracy rate. This is comparable with the screw accuracy rate of 93.7% reported for adult navigated pedicle screws. Further, navigation prevented attempts of screw placement at levels with absent or impassable pedicles. Image-guided navigation and intraoperative CT are valuable tools for the safe placement of pedicle screws in patients with significant congenital spine deformity and altered anatomy. Level of Evidence: IV, Case Series.

Sagittal balance and spinopelvic parameters after lateral lumbar interbody fusion for degenerative scoliosis: A case-control study

Study Design. Retrospective matched-cohort analysis. Objective. To evaluate the change in radiographical parameters in patients undergoing interbody fusion and posterior instrumentation compared with posterior spine fusion (PSF) alone for degenerative scoliosis. Summary of Background Data. Little is known about the effect of lateral interbody fusion (LIF) on sagittal plane correction in the setting of degenerative scoliosis. We performed a retrospective study to investigate these changes compared with PSF. Methods. Between 1997 and 2011, 33 patients had LIF at 181 levels between T8 and L5 vertebrae for the treatment of degenerative scoliosis (mean; 5 ± 2 levels). Of those, 23 patients had additional anterior lumbar interbody fusion (ALIF) at 37 levels between L4 and S1 vertebrae (mean; 1.6 ± 0.5 levels). A 1:1 matched control of patients who underwent PSF was performed. Patients were matched by age, sex, and diagnosis. Clinical and radiographical data were collected and compared between the matched cohorts. Results. Lumbar lordosis (LL) was significantly restored in the LIF ± ALIF compared with PSF cohort (44° ± 14° vs. 36° ± 15°, P = 0.02). The segmental LL over the 102 LIF levels significantly improved from 12°± 10° to 21°± 13° postoperatively (P < 0.0001). However, the change over the 37 ALIF levels was not significant (from 30° ± 15° to 29° ± 9°, P = 0.8). Sagittal plane alignment was improved in the LIF ± ALIF compared with PSF cohort and trended toward but did not reach significance (3.8 ± 3.2 cm vs. 6.2 ± 5.7 cm, P = 0.09). Sacral slope was significantly higher in the LIF ± ALIF compared with PSF cohort (33° ± 11° vs. 28° ± 10°, P = 0.03). Pelvic tilt was lower in the LIF ± ALIF compared with PSF cohort and trended toward but did not reach significance (22° ± 10° vs. 26° ± 10°, P = 0.08). Conclusion. LL and sacral slope had mildly but statistically improved in the interbody fusion cohort compared with PSF cohort. Sagittal alignment and pelvic tilt trended toward but did not reach statistical significance. Segmental LL was improved at LIF levels more than at ALIF levels. Level of Evidence: 3

Motocross morbidity: Economic cost and injury distribution in children

Background Motocross is a nationally organized sport that is growing in popularity. The distribution and severity of motocross injuries in the pediatric population is not known. We hypothesize a high rate of musculoskeletal injuries requiring hospitalization and/or surgical intervention. Methods All patients 17 years of age or younger with injuries sustained while using off-road 2-wheeled motorcycles were identified through surgical, diagnostic, and trauma registries at a level 1 regional trauma center. Type, severity, and mechanism of injury were assessed, as well as charges billed for medical care. Both recreational and competitive motocross activities were included. Results From 2000 to 2007, 299 cases were noted in 249 unique patients. In 141 instances, hospital admission was required, for a total of 412 inpatient days. Twenty patients required ICU admission. Surgery was performed in 91 cases (81 orthopaedic, 6 general, 1 urology, and 4 facial reconstructions). Orthopaedic surgical procedures included treatment of 29 femur fractures, 8 forearm, 6 ankle, 5 tibial shaft, 6 proximal tibia, 5 spine, 6 proximal humerus, 4 hand, 4 foot, 3 elbow fractures, and 5 other. Orthopaedic interventions also included 8 reductions under general anesthesia and 31 conscious sedations. Mean age at injury was 14.1 years (range: 5.4 to 17.9). Ninety-four percent of patients were male and 85% were White. The majority of patients were wearing helmets/safety equipment. One hundred and eighty-four injuries occurred on a track, with 150 during competition. The mean charge billed per injury was

Lumbar curve is stable after selective thoracic fusion for adolescent idiopathic scoliosis: a 20-year follow-up.

14,947 (range:

Identification and validation of multiple cell surface markers of clinical-grade adipose-derived mesenchymal stromal cells as novel release criteria for good manufacturing practice-compliant production

105 to