Brian J. Rebolledo

Reduced cortical bone compositional heterogeneity with bisphosphonate treatment in postmenopausal women with intertrochanteric and subtrochanteric fractures.

Reduction of bone turnover with bisphosphonate treatment alters bone mineral and matrix properties. Our objective was to investigate the effect of bisphosphonate treatment on bone tissue properties near fragility fracture sites in the proximal femur in postmenopausal women with osteoporosis. The mineral and collagen properties of corticocancellous biopsies from the proximal femur were compared in bisphosphonate‐naive (−BIS, n = 20) and bisphosphonate‐treated (+BIS, n = 20, duration 7 ± 5 years) patients with intertrochanteric (IT) and subtrochanteric (ST) fractures using Fourier transform infrared imaging (FTIRI). The mean values of the FTIRI parameter distributions were similar across groups, but the widths of the parameter distributions tended to be reduced in the +BIS group relative to the −BIS group. Specifically, the widths of the cortical collagen maturity and crystallinity were reduced in the +BIS group relative to those of the −BIS group by 28% (+BIS 0.45 ± 0.18 versus −BIS 0.63 ± 0.28, p = 0.03) and 17% (+BIS 0.087 ± 0.012 versus −BIS 0.104 ± 0.036, p = 0.05), respectively. When the tissue properties were examined as a function of fracture morphology within the +BIS group, the FTIR parameters were generally similar regardless of fracture morphology. However, the cortical mineral:matrix ratio was 8% greater in tissue from patients with atypical ST fractures (n = 6) than that of patients with typical (IT or spiral ST) fractures (n = 14) (Atypical 5.6 ± 0.3 versus Typical 5.2 ± 0.5, p = 0.03). Thus, although the mean values of the FTIR properties were similar in both groups, the tissue in bisphosphonate‐treated patients had a more uniform composition than that of bisphosphonate‐naive patients. The observed reductions in mineral and matrix heterogeneity may diminish tissue‐level toughening mechanisms.

Operative Management of Ulnar Collateral Ligament Insufficiency in Adolescent Athletes

Background: The incidence of ulnar collateral ligament (UCL) injuries of the elbow has increased in adolescents over the past decade because of widespread participation in athletics and heightened awareness among physicians. Hypothesis: Ulnar collateral ligament reconstruction using the docking technique would result in a successful return to athletic activity in this age group. Study Design: Case series; Level of evidence, 4. Methods: Study participants were 55 skeletally mature adolescent athletes (mean age, 17.6 years; range, 15-18 years) who underwent UCL reconstruction between 2008 and 2010. While the majority of patients were baseball players (n = 47), there were 3 gymnasts and 5 javelin throwers included in the study. Each patient underwent UCL reconstruction utilizing the docking technique after an adequate trial of nonoperative management (mean, 5.8 months). At the latest follow-up, patients were evaluated to determine their ability to return to athletic activity. Clinical outcomes were classified using the Conway scale, the Andrews-Timmerman score, and the Kerlan-Jobe Orthopaedic Clinic (KJOC) score. Results: At a minimum 2-year follow-up, 87% (48/55) of patients had excellent results using the Conway scale. Overall, there were only 2 poor results (3.6%) that were observed in patients with concomitant osteochondritis dissecans lesions of the capitellum. There were 4 postoperative complications in 4 patients (2 gymnasts and 2 javelin throwers) who developed ulnar neuritis after UCL reconstruction. The mean Andrews-Timmerman score was 83.6 ± 7.2 (range, 30-100), and the mean KJOC score was 88.0 ± 6.0 (range, 40-100). Conclusion: The docking technique results in favorable clinical outcomes in adolescent athletes with UCL insufficiency at a minimum of 2 years postoperatively. Patients with concomitant intra-articular lesions should be cautioned preoperatively that they might experience inferior clinical outcomes. Postoperatively, adolescent gymnasts and javelin throwers may be at an increased risk for transient paresthesia of the ulnar nerve caused by increased stress on the medial elbow.

Diseases Affecting Bone Quality: Beyond Osteoporosis

BackgroundBone quantity, quality, and turnover contribute to whole bone strength. Although bone mineral density, or bone quantity, is associated with increased fracture risk, less is known about bone quality. Various conditions, including disorders of mineral homeostasis, disorders in bone remodeling, collagen disorders, and drugs, affect bone quality.Questions/purposesThe objectives of this review are to (1) identify the conditions and diseases that could adversely affect bone quality besides osteoporosis, and (2) evaluate how these conditions influence bone quality.MethodsWe searched PubMed using the keywords “causes” combined with “secondary osteoporosis” or “fragility fracture.” After identifying 20 disorders/conditions, we subsequently searched each condition to evaluate its effect on bone quality.ResultsMany disorders or conditions have an effect on bone metabolism, leading to fragility fractures. These disorders include abnormalities that disrupt mineral homeostasis, lead to an alteration of the mineralization process, and ultimately reduce bone strength. The balance between bone formation and resorption is also essential to prevent microdamage accumulation and maintain proper material and structural integrity of the bone. As a result, diseases that alter the bone turnover process lead to a reduction of bone strength. Because Type I collagen is the most abundant protein found in bone, defects in Type I collagen can result in alterations of material property, ultimately leading to fragility fractures. Additionally, some medications can adversely affect bone.ConclusionsRecognizing these conditions and diseases and understanding their etiology and pathogenesis is crucial for patient care and maintaining overall bone health.

Increased Lateral Tibial Slope Is a Risk Factor for Pediatric Anterior Cruciate Ligament Injury: An MRI-Based Case-Control Study of 152 Patients

Background: Increased posterior tibial slope is associated with increased risk of anterior cruciate ligament (ACL) injury in adults. A similar association has not been rigorously examined in children and adolescents. Purpose: To determine whether alterations in posterior tibial slope are associated with ACL tears in pediatric and adolescent patients and to quantify changes in tibial slope by age. Study Design: Case-control study; Level of evidence, 3. Methods: Magnetic resonance imaging (MRI) studies of the knee were reviewed by 3 raters blinded to each other in a 1:1 sample of cases and age- and sex-matched controls. A total of 76 skeletally immature ACL-injured knees were compared with 76 knees without ACL injury; the mean age of the study population was 14.8 ± 1.3 years. The posterior slope of the articular surface of the medial tibial plateau and lateral tibial plateau was measured by use of a method similar to that used in previous studies in adult populations. The current study technique differed in that the slope was measured on the cartilage surface, not the subchondral bone. Comparisons between knees were made with t tests, and Spearman correlation analysis was used to assess changes in tibial slope with advancing age. Results: Increased slope of the lateral tibial plateau (LTS) was significantly increased in ACL-injured patients compared with controls (5.7° ± 2.4° vs 3.4° ± 1.7°; P < .001). There was no statistically significant difference in the slope of the medial tibial plateau (MTS) in the ACL-injured and control knees (5.4° ± 2.2° vs 5.1° ± 2.3°; P = .42). There was no difference in LTS between male and female patients (4.46° vs 4.58°; P = .75). Receiver operating characteristic (ROC) analysis of the LTS revealed that a posterior tibial slope cutoff of >4° resulted in a sensitivity of 76% and a specificity of 75% for predicting ACL tears in this cohort. Spearman correlation analysis revealed that MTS and LTS decreased, or flattened, by 0.31° (P = .028, correlation coefficient r = −0.18) and 0.37° (P = .009, correlation coefficient r = −0.21) per year, respectively, as adolescents age. Conclusion: The LTS was significantly associated with an increased risk of ACL injury in pediatric and adolescent patients. The MTS was not associated with risk of injury. Posterior slope was found to decrease, or flatten, with age. A cutoff of >4° for the posterior slope of the lateral compartment is 76% sensitive and 75% specific for predicting ACL injury in this cohort. The LTS did not influence the incidence of ACL injury differently between sexes.

Patient specific cutting guides versus an imageless, computer-assisted surgery system in total knee arthroplasty

BACKGROUND Patient specific cutting guides (PSC) in total knee arthroplasty (TKA) have recently been introduced, in which preoperative 3-dimensional imaging is used to manufacture disposable cutting blocks specific to a patients anatomy. The purpose of this study was to compare the alignment accuracy of PSC to an imageless CAS system in TKA. METHODS Thirty-seven patients (41 knees), received a TKA using an imageless CAS system. Subsequently, 38 patients (41 knees), received a TKA using a MRI-based, PSC system. Postoperatively, standing AP hip-to-ankle radiographs were obtained, from which the lower extremity mechanical axis, tibial component varus/valgus, and femoral component varus/valgus mechanical alignment were digitally measured. Each measurement was performed by two blinded, independent observers, and interclass correlations were calculated. A students two-tailed t test was used to compare the two cohorts (p-value<0.05=significant). RESULTS In the PSC cohort, 70.7% of patients had an overall alignment within 3° of a neutral mechanical axis (vs. 92.7% with CAS, p=0.02), 87.8% had a tibial component alignment within 2° of perpendicular to the tibial mechanical axis (vs. 100% with CAS, p=0.04), and 90.2% had a femoral component alignment within 2° of perpendicular to the femoral mechanical axis (vs. 100% with CAS, p=0.2). Interclass correlation coefficients were good to excellent for all radiographic measurements. CONCLUSION While PSC techniques appear sound in principle, this study did not demonstrate patient specific cutting guides to obtain the same degree of overall mechanical and tibial component alignment accuracy as a CAS technique. LEVEL OF EVIDENCE III: Retrospective cohort study.

Does Vitamin D Status Affect the Attainment of In-Hospital Functional Milestones After Total Hip Arthroplasty?

Our study aims to identify the prevalence of low vitamin D status in patients undergoing total hip arthroplasty (THA) and to evaluate the association between serum vitamin D level and the attainment of in-hospital functional milestones. We collected data from patients who underwent THA and had preoperative serum vitamin D (serum 25-hydroxy vitamin D) levels measured. From 200 patients, 79 (39.5%) had low serum vitamin D (serum 25-hydroxy vitamin D <32 ng/mL). There were no associations between serum vitamin D level and the attainment of in-hospital functional milestones as well as length of hospital stay or perioperative complications after THA. Because low vitamin D status did not compromise the short-term functional outcomes after THA, surgery need not be delayed, but low vitamin D levels should be corrected once identified.

Arthroscopy Skills Development with a Surgical Simulator: A Comparative Study in Orthopaedic Surgery Residents

Objectives: Traditional resident assessment of orthopaedic surgical technical proficiency relies exclusively on subjective parameters. More standardized objective measures are needed to ensure training consistency and surgical competency. The purpose of this study was to determine if orthopaedic surgery residents who train with a virtual reality simulator can lead to improved arthroscopy performance and to determine if a standardized arthroscopic shoulder and knee test were appropriate means for evaluating a residents arthroscopic skill after completing a training course. Methods: Study participants were first and second year orthopaedic surgery residents at a single institution who were randomized to either train on the virtual reality surgical simulator (Insight Arthro VR) for a total of 2.5 hours (n=8) or receive 2 hours of didactic lectures with models (non-simulator) (n=6). Both groups were then evaluated in both knee and shoulder arthroscopy using a cadaver. Performance was measured by time to completion of a standardized protocol checklist and cartilage grading index (CGI) (scale 0-10). Results: All subjects had no previous arthroscopy experience prior to the study. The simulator group had a shorter time to completion in both knee (simulator: 5.1 ± 1.8 min, non-simulator: 8.0 ± 4.4 min; p=0.09) and shoulder (simulator: 6.1 ± 1.5 min, non-simulator: 9.9 ± 3.2 min; p=0.02) arthroscopy. Similarly, the simulator group had improved CGI scores in both the knee (simulator: 4.0 ± 1.1, non-simulator: 5.3 ± 1.5; p=0.07) and shoulder (simulator: 3.4 ± 0.8, non-simulator: 5.5 ± 1.6; p=0.008) arthroscopy. Conclusion: This study suggests that surgical simulators are beneficial in arthroscopy skills development for orthopaedic surgery residents. An arthroscopic testing model was able to measure a statistical improvement for a residents arthroscopic skill. Instituting standardized cadaveric testing based on common orthopaedic surgical procedures such as knee and shoulder arthroscopy will not only ensure graduating residents possess the necessary skills to be technically proficient surgeons but it will also allow objective identification of residents in need of remediation.

A Comprehensive Approach to Fragility Fractures

To address the cause of fragility fractures, an understanding of the determinants of bone strength is needed. Identifying patients at increased fracture risk should take into account bone quantity, quality, and turnover. Postmenopausal osteoporosis remains the most common derangement of bone strength; however, decreased bone strength can also result from secondary causes of osteoporosis. In order to properly manage patients with fragility fractures, assessment should include a focused medical history and physical examination, proper laboratory investigation, dual-energy x-ray absorptiometry screening, and, if necessary, use of the fracture risk assessment tool (FRAX). Treatment options will include nonpharmacologic treatment such as calcium and vitamin D and pharmacologic treatment with antiresorptive or anabolic agents to prevent future fractures. Bisphosphonates remain the standard treatment for osteoporosis. Concerns of oversuppression of bone turnover on long-term bisphosphonate treatment can be addressed with a drug holiday depending on the patients fracture risk. An anabolic agent such as teriparatide is a powerful tool for the prevention of fragility fractures and should be reserved for patients at high risk for fracture, such as those with declining bone mineral density despite bisphosphonate treatment. Careful evaluation of all patients with a fragility fracture will enable the orthopaedic surgeon to identify the cause of fracture and implement a treatment plan that can prevent subsequent fractures in this vulnerable population.

Defining the “Substantial Clinical Benefit” After Arthroscopic Treatment of Femoroacetabular Impingement

Background: The minimal clinically important difference (MCID) has been defined in orthopaedics and is the smallest change that a patient considers meaningful. Less is known about improvements that the patient perceives as clinically considerable, or the substantial clinical benefit (SCB). For the young, highly functioning patient cohort with femoroacetabular impingement (FAI), the SCB is an important measure of clinical success. Purpose: To derive the SCB for FAI treatment and identify outcome score thresholds and patient variables predictive of the SCB. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: The modified Harris Hip Score (mHHS), the Hip Outcome Score activities of daily living (HOS-ADL) and sport (HOS-Sport) subscales, and the international Hip Outcome Tool (iHOT-33) were prospectively administered to 364 patients with a minimum 1-year follow-up. At 1 year postoperatively, patients graded their hip function based on several anchor responses such as “no change” and “much improved.” The SCB was defined as the change on each outcome tool that equated to the difference between “no change” and “much improved” on the health transition question. Receiver operating characteristic analysis with area under the curve (AUC) was used to identify optimal values that were most representative of the SCB. Multivariable analysis identified patient variables predictive of the SCB. Results: The net change in outcome scores corresponding to the SCB for the mHHS, HOS-ADL, HOS-Sport, and iHOT-33 was 19.8, 10.0, 29.9, and 24.5, respectively. The following postoperative outcome scores demonstrated excellent distinction (AUC >0.8) between “no change” and “much improved” and thus were considered absolute values for the postoperative SCB: 82.5 (mHHS), 93.3 (HOS-ADL), 84.4 (HOS-Sport), and 63.5 (iHOT-33). Preoperative scores on the HOS-ADL (83.3) and HOS-Sport (50.0) were significant threshold cutoffs, above which attaining the SCB became less likely. Younger age and lower Outerbridge grade were predictive of achieving the SCB. Conclusion: The SCB has not been previously defined in the hip preservation literature and is complementary to the MCID as the upper bound for clinically significant improvement. We identified predictive preoperative and diagnostic postoperative outcome scores for the SCB that can be used to manage patient expectations and grade outcomes. These findings are objective criteria for defining clinical success after arthroscopic FAI treatment.

Arrhythmias in the setting of hematopoietic cell transplants

Prior studies report that 9–27% of persons receiving a hematopoietic cell transplant develop arrhythmias, but the effect on outcomes is largely unknown. We reviewed data from 1177 consecutive patients ⩾40 years old receiving a hematopoietic cell transplant at one center during 1999–2009. Transplant indication was predominately leukemia, lymphoma and multiple myeloma. Overall, 104 patients were found to have clinically significant arrhythmia: 43 before and 61 after transplant. Post-transplant arrhythmias were most frequently atrial fibrillation (N=30), atrial flutter (N=7) and supraventricular tachycardia (N=11). Subjects with an arrhythmia post transplant were more likely to have longer median hospital stays (32 days vs 23, P=<0.001), a greater probability of an intensive care unit admission (52% vs 7%; P<0.001), greater probability of in-hospital deaths (28% vs 3%, P<0.001), and greater probability of death within 1 year of transplant (41% vs 15%; P<0.001) compared with patients without arrhythmia at any time. In a multivariate model including age at transplant, diagnosis, history of pretransplant arrhythmia, and transplant-related variables, post-transplant arrhythmia was associated with a greater risk for death within a year of transplant (odds ratio 3.5, 95% confidence interval: 2.1, 5.9; P<0.001). Our data suggest that arrhythmias after transplants are associated with significant morbidity and mortality. A prospective study of arrhythmia in the transplant setting is warranted.