Amyloid Deposition: An Unusual Case of Deep Gluteal Syndrome and Sciatic Nerve Compression: A Case Report.

CASE: Soft-tissue amyloidomas are exceedingly rare, with only a few cases reported in the literature. There are no reports of sciatic nerve compression secondary to a soft-tissue amyloidoma. We report a unique case of a 71-year-old man with an incidentally found amyloidoma who was initially believed to have deep gluteal syndrome. He had a favorable outcome after surgical decompression. CONCLUSION: For patients who do not have classic examination and electromyography/nerve conduction findings of piriformis syndrome, providers should explore other etiologies of peripheral nerve compression including soft-tissue amyloidoma.

The effect of surgeon-controlled variables on construct stiffness in lateral locked plating of distal femoral fractures.

BACKGROUND: Nonunion following treatment of supracondylar femur fractures with lateral locked plates (LLP) has been reported to be as high as 21 %. Implant related and surgeon-controlled variables have been postulated to contribute to nonunion by modulating fracture-fixation construct stiffness. The purpose of this study is to evaluate the effect of surgeon-controlled factors on stiffness when treating supracondylar femur fractures with LLPs: 1. Does plate length affect construct stiffness given the same plate material, fracture working length and type of screws? 2. Does screw type (bicortical locking versus bicortical nonlocking or unicortical locking) and number of screws affect construct stiffness given the same material, fracture working length, and plate length? 3. Does fracture working length affect construct stiffness given the same plate material, length and type of screws? 4. Does plate material (titanium versus stainless steel) affect construct stiffness given the same fracture working length, plate length, type and number of screws? METHODS: Mechanical study of simulated supracondylar femur fractures treated with LLPs of varying lengths, screw types, fractureworking lenghts, and plate/screw material. Overall construct stiffness was evaluated using an Instron hydraulic testing apparatus. RESULTS: Stiffness was 15 % higher comparing 13-hole to the 5-hole plates (995 N/mm849N vs. /mm, p = 0.003). The use of bicortical nonlocking screws decreased overall construct stiffness by 18 % compared to bicortical locking screws (808 N/mm vs. 995 N/mm, p = 0.0001). The type of screw (unicortical locking vs. bicortical locking) and the number of screws in the diaphysis (3 vs. 10) did not appear to significantly influence construct stiffness (p = 0.76, p = 0.24). Similarly, fracture working length (5.4 cm vs. 9.4 cm, p = 0.24), and implant type (titanium vs. stainless steel, p = 0.12) did also not appear to effect stiffness. DISCUSSION: Using shorter plates and using bicortical nonlocking screws (vs. bicortical locking screws) reduced overall construct stiffness. Using more screws, using unicortical locking screws, increasing fracture working length and varying plate material (titanium vs. stainless steel) does not appear to significantly alter construct stiffness. Surgeons can adjust plate length and screw types to affect overall fracture-fixation construct stiffness; however, the optimal stiffness to promote healing remains unknown.

Radiostereometric Analysis of Stability and Inducible Micromotion After Locked Lateral Plating of Distal Femur Fractures.

OBJECTIVES: To evaluate interfragmentary motion over 1 year after distal femoral fracture fixation using radiostereometric analysis (RSA). The secondary aim was to assess whether RSA data are consistent with diagnoses of nonunion. DESIGN: Prospective cohort study. SETTING: Level I urban trauma center. PATIENTS: Sixteen patients between 22 and 89 years of age with distal femoral fracture (OTA/AO type 33). INTERVENTION: All fractures were treated with a lateral locking plate, and tantalum markers were inserted into the main proximal and distal fracture fragments. RSA was performed at 2, 6, 12, 18, and 52 weeks postoperatively. Both unloaded and loaded RSA measurements were performed. MAIN OUTCOME MEASUREMENTS: Unloaded fracture migration over time and inducible micromotion at the fracture site in the coronal plane were determined at each follow-up interval. RESULTS: RSA precision in the coronal plane of interfragmentary motion over time and inducible micromotion were 1.2 and 0.9 mm in the coronal plane, respectively. Two cases required revision surgery for nonunion 1 year postoperatively. For cases of union, unloaded fracture migration stopped being detectable between 12 and 18 weeks, and inducible micromotion was no longer detectable by the 12-week visit. For cases of nonunion, both unloaded migration and inducible micromotion were detected throughout the study period. CONCLUSIONS: RSA may be used to reliably assess distal femoral fracture healing. RSA revealed differences in cases of union and nonunion by 3 months and more consistently than traditional x-rays. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

The expansion and validation of a new upper extremity item bank for the Patient-Reported Outcomes Measurement Information System® (PROMIS).

BACKGROUND: The Patient-Reported Outcomes Measurement Information System® (PROMIS) includes a Physical Function (PF) item bank and an Upper Extremity (UE) item bank, which is composed of a subset of items from the PF bank. The UE item bank has few items and known ceiling effects. Therefore, this study aimed to expand the item bank to assess a wider range of functioning. With the additional content, other psychometric properties-improved content validity, item bank depth, range of measurement, and score reliability-were also evaluated. We convened an expert panel to review potential items, and then conducted psychometric analyses on both extant and newly-collected data. RESULTS: Expert focus groups reviewed the PF item bank for items that were "sufficiently" related to upper extremity functioning for inclusion in the expanded UE item bank. The candidate item bank was quantitatively evaluated in a new sample of 600 people. The final items were calibrated in an aggregated dataset (n = 11,635) from two existing datasets, and the newly collected sample. The original UE item bank included 15 items. After expert review and quantitative evaluation, 31 items were added. The combined 46 items were calibrated using item response theory (IRT). Then computer adaptive tests (CATs) were simulated based off of the psychometric results. These indicated that the new UE item bank has an extended measurement range compared to the original version. CONCLUSIONS: The expanded PROMIS UE item bank assesses a wider range of upper extremity functioning compared to the initial UE item bank. However, ceiling effects remain a concern for unimpaired groups. The new UE item bank is recommended for individuals with known or suspected upper extremity limitations.

Validation of PROMIS Physical Function Instruments in Patients With an Orthopaedic Trauma to a Lower Extremity.

OBJECTIVES: To evaluate the reliability, convergent validity, known-groups validity, and responsiveness of the Patient-Reported Outcomes Measurement Information System (PROMIS) Mobility Computer Adaptive Test (CAT) and PROMIS Physical Function 8a Short Form. DESIGN: Prospective cohort study. SETTING: Two Level-I trauma centers. PATIENTS: Eligible adults with an isolated lower extremity trauma injury receiving treatment were approached consecutively (n = 402 consented at time 1, median = 80 days after treatment). After 6 months, 122 (30.3%) completed another assessment. INTERVENTION: Cross-sectional and longitudinal monitoring of patients. MAIN OUTCOME MEASUREMENTS: Floor and ceiling effects, reliability (marginal reliability and Cronbach's alpha), convergent validity, known-groups discriminant validity (weight-bearing status and fracture severity), and responsiveness (Cohen's d effect size) were evaluated for the PROMIS Mobility CAT, PROMIS Physical Function 8a Short Form, and 5 other measures of physical function. RESULTS: PROMIS PFSF8a and Foot and Ankle Ability Measure Activities of Daily Living Index had ceiling effects. Both PROMIS measures demonstrated excellent internal consistency reliability (mean marginal reliability 0.94 and 0.96; Cronbach's alpha = 0.96). Convergent validity was supported by high correlations with other measures of physical function (r = 0.70-0.87). Known-groups validity by weight-bearing status and fracture severity was supported as was responsiveness (Mobility CAT effect size = 0.81; Physical Function Short Form 8a = 0.88). CONCLUSIONS: The PROMIS Mobility CAT and Physical Function 8a Short Form demonstrated reliability, convergent and known-groups discriminant validity, and responsiveness in a sample of patients with a lower extremity orthopaedic trauma injury.

AO Patient Outcomes Center: Design, Implementation, and Evaluation of a Software Application for the Collection of Patient-Reported Outcome Measures in Orthopedic Outpatient Clinics.

BACKGROUND: Patient-reported outcomes are increasingly utilized in routine orthopedic clinical care. Computer adaptive tests (CATs) from the Patient-Reported Outcomes Measurement Information System (PROMIS) offer a brief and precise assessment that is well suited for collection within busy clinical environments. However, software apps that support the administration and scoring of CATs, provide immediate access to patient-reported outcome (PRO) scores, and minimize clinician burden are not widely available. OBJECTIVE: Our objective was to design, implement, and test the feasibility and usability of a Web-based system for collecting CATs in orthopedic clinics. METHODS: AO Patient Outcomes Center (AOPOC) was subjected to 2 rounds of testing. Alpha testing was conducted in 3 orthopedic clinics to evaluate ease of use and feasibility of integration in clinics. Patients completed an assessment of PROMIS CATs and a usability survey. Clinicians participated in a brief semistructured interview. Beta-phase testing evaluated system performance through load testing and usability of the updated version of AOPOC. In both rounds of testing, user satisfaction, bugs, change requests, and performance of PROMIS CATs were captured. RESULTS: Patient feedback supported the ease of use in completing an assessment in AOPOC. Across both phases of testing, clinicians rated AOPOC as easy to use but noted difficulties in integrating a Web-based software application within their clinics. PROMIS CATs performed well; the default assessment of 2 CATs was completed quickly (mean 9.5 items) with a satisfactory range of measurement. CONCLUSION: AOPOC was demonstrated to be an easy-to-learn and easy-to-use software application for patients and clinicians that can be integrated into orthopedic clinical care. The workflow disruption in integrating any type of PRO collection must be addressed if patients' voices are to be better integrated in clinical care.

Self-Reported Marijuana Use Is Associated with Increased Use of Prescription Opioids Following Traumatic Musculoskeletal Injury.

BACKGROUND: Cannabinoids are among the psychoactive substances considered as alternatives to opioids for the alleviation of acute pain. We examined whether self-reported marijuana use was associated with decreased use of prescription opioids following traumatic musculoskeletal injury. METHODS: Our analysis included 500 patients with a musculoskeletal injury who completed a survey about their marijuana use and were categorized as (1) never a user, (2) a prior user (but not during recovery), or (3) a user during recovery. Patients who used marijuana during recovery indicated whether marijuana helped their pain or reduced opioid use. Prescription opioid use was measured as (1) persistent opioid use, (2) total prescribed opioids, and (3) duration of opioid use. Persistent use was defined as the receipt of at least 1 opioid prescription within 90 days of injury and at least 1 additional prescription between 90 and 180 days. Total prescribed opioids were calculated as the total morphine milligram equivalents (MME) prescribed after injury. Duration of use was the interval between the first and last opioid prescription dates. RESULTS: We found that 39.8% of patients reported never having used marijuana, 46.4% reported prior use but not during recovery, and 13.8% reported using marijuana during recovery. The estimated rate of persistent opioid use ranged from 17.6% to 25.9% and was not associated with marijuana use during recovery. Marijuana use during recovery was associated with increases in both total prescribed opioids (regression coefficient = 343 MME; 95% confidence interval [CI] = 87 to 600 MME; p = 0.029) and duration of use (coefficient = 12.5 days; 95% CI = 3.4 to 21.5 days; p = 0.027) compared with no previous use (never users). Among patients who reported that marijuana decreased their opioid use, marijuana use during recovery was associated with increased total prescribed opioids (p = 0.008) and duration of opioid use (p = 0.013) compared with never users. CONCLUSIONS: Our data indicate that self-reported marijuana use during injury recovery was associated with an increased amount and duration of opioid use. This is in contrast to many patients' perception that the use of marijuana reduces their pain and therefore the amount of opioids used. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Use of Patient-Related Outcomes After Orthopaedic Trauma: Helpful or Not So Much?

Over 100 years ago, the orthopaedic surgeon, Ernest Codman, recommended that surgeons and hospitals be paid by the "end result." Healthcare Reform is moving to value over volume, and patient-reported outcomes (PROs) are 1 measure of quality and outcomes that are becoming pervasive. In this study, the current status of patient-reported outcomes and their use in orthopaedic trauma was reviewed. The contributors presented the state of PRO measurements at the Basic Science Focus Forum at the OTA Annual Meeting in 2016. Information on the currently available PROs was presented and analyzed to determine whether they were adequate for research in orthopaedic trauma. PROs were then discussed in the context of which were the most appropriate for determining outcomes in trauma surgery. The concept of mobility as a validated PRO for an assessment of general health was then presented. The final topic was a summary of how PROs will be used by insurers and governmental agencies. These topics provide a comprehensive overview of the current state of PROs in the context of orthopaedic trauma.

Does Total Hip Arthroplasty Reduce the Risk of Secondary Surgery Following the Treatment of Displaced Acetabular Fractures in the Elderly Compared to Open Reduction Internal Fixation? A Pilot Study.

OBJECTIVES: The goal of open reduction and internal fixation (ORIF) is to anatomically reduce the facture and maintain a congruent hip joint. However, ORIF in the elderly is technically challenging. Therefore, there are advocates for acute total hip arthroplasty (THA) in this patient population. The primary purpose of this study was to evaluate the rate of revision surgery in elderly patients with acetabular fractures treated with ORIF or THA. The secondary purpose was to compare patient's self-reported functional outcomes. DESIGN: Retrospective review. SETTING: Two American College of Surgeons Level 1 trauma centers. PATIENTS/PARTICIPANTS: Thirty-three patients were treated with ORIF and 37 were treated with THA. The mean follow-up was 22 months (range 6-89 months). Patients were interviewed, and radiographs were examined. INTERVENTION: Treatment of displaced acetabular fractures with either ORIF or THA. MAIN OUTCOME MEASUREMENTS: Need for reoperation. Harris Hip Score and SF-36 questionnaire. RESULTS: Those treated with ORIF had a higher rate of reoperation (10/33, 30%) compared with those treated with THA (5/37, 14%); however, this was not statistically significant (P = 0.12). Patients reported better bodily pain scores as measured by SF-36 (48 vs. 39, P = 0.04), and a trend toward improved function as measured by patient reported Harris Hip Scores (82 vs. 63, P = 0.06) in those treated with THA compared with ORIF. CONCLUSIONS: Acute reconstruction of acetabular fractures with THA in the geriatric population seems to compare favorably with ORIF, with a similar rate of complications, but with improved pain scores. In addition, there was a high rate of conversion to THA within 2 years of injury when patients were treated with ORIF. Acute THA as primary treatment in this patient population merits further, more controlled, comparative study. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Patient Perceptions of the Use of Medical Marijuana in the Treatment of Pain After Musculoskeletal Trauma: A Survey of Patients at 2 Trauma Centers in Massachusetts.

OBJECTIVE: To evaluate musculoskeletal trauma patients' beliefs regarding the usefulness of marijuana as a valid medical treatment for postinjury and postoperative pain and anxiety. DESIGN: Prospective survey. SETTING: Two academic Level 1 trauma centers. PATIENTS/PARTICIPANTS: Five hundred patients in an orthopedic outpatient clinic. INTERVENTION: Survey. MAIN OUTCOME MEASUREMENTS: (1) Do patients believe that marijuana can be used as medicine? (2) Do patients believe that marijuana can help treat postinjury pain? (3) Are patients comfortable speaking with their health care providers about medical marijuana? RESULTS: The majority of patients felt that marijuana could be used to treat pain (78%, 390) and anxiety (62%, 309). Most patients (60%, 302) had used marijuana at least once previously, whereas only 14% reported using marijuana after their injury. Of those who used marijuana during their recovery, 90% (63/70) believed that it reduced symptoms of pain, and 81% (57/70) believed that it reduced the amount of opioid pain medication they used. CONCLUSIONS: The majority of patients in this study believed that medical marijuana is a valid treatment and that it does have a role in reducing postinjury and postoperative pain. Those patients who used marijuana during their recovery felt that it alleviated symptoms of pain and reduced their opioid intake. Our results help inform clinicians regarding the perceptions of patients with trauma regarding the usefulness of marijuana in treating pain and support further study into the utility of medical marijuana in this population.

Longitudinal Validation of the PROMIS Physical Function Item Bank in Upper Extremity Trauma.

OBJECTIVES: To evaluate the reliability, validity, and responsiveness of the Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity Computer Adaptive Test (UE-CAT) and the 8-item Physical Function short form (PF-SF8a) for monitoring outcomes after musculoskeletal injuries in upper extremity trauma patients. DESIGN: Prospective cohort study. SETTING: Two Level-I trauma centers. PATIENTS: Eligible consecutive patients were approached and 424 consented at time 1 (median 9.7 weeks posttreatment). After 6 months, 132 patients (43% of the 307 eligible) completed follow-up measures. INTERVENTION: Cross-sectional and longitudinal monitoring of upper extremity trauma patients treated with or without surgery. MAIN OUTCOME MEASUREMENTS: Reliability, validity, and responsiveness of the UE-CAT and PF-SF8a. Internal consistency reliability, convergent validity correlations, and discriminant validity (by fracture severity and dominant/nondominant extremity groups) were calculated for PROMIS and non-PROMIS forms. Floor and ceiling effects were also examined at both assessment occasions. Responsiveness was evaluated using random-intercept mixed effects models and effect sizes. RESULTS: PROMIS measures had excellent reliability, correlated well with legacy measures, and were responsive to treatment. CONCLUSIONS: PROMIS measures had good statistical properties. In addition to the known advantages of PROMIS, such as lower patient burden and the ability to assess the broadest range of functioning, our data demonstrated that for patients with upper extremity limitations, a region-specific measure such as the UE-CAT may perform more favorably than an overall/full body physical function measure.

Time From Injury to Surgical Fixation of Diaphyseal Humerus Fractures Is Not Associated With an Increased Risk of Iatrogenic Radial Nerve Palsy.

OBJECTIVES: To determine whether time from injury to fixation of diaphyseal humeral fractures and nonunions is associated with the risk of iatrogenic radial nerve palsy. DESIGN: Retrospective review. SETTING: Two Level 1 trauma centers. PATIENTS/PARTICIPANTS: Between 2001 and 2015, 325 patients who had documented intact radial nerve function preoperatively were treated with fixation of a humerus fracture or humerus nonunion. INTERVENTION: Open reduction and internal fixation. MAIN OUTCOME MEASUREMENTS: Development of an iatrogenic radial nerve injury. Those with an injury were followed to either resolution of the nerve palsy or definitive treatment. RESULTS: The risk of iatrogenic radial nerve palsy was 7.7% (25/325). Time to surgery was not significantly associated with iatrogenic radial nerve palsy. In a multiple variable analysis, when comparing patients treated within 4 weeks to those treated 4-8 weeks (P = 0.41), 8-12 weeks (P = 0.94), and over 12 weeks (0.20), there were no significant associations. Independent risk factors for iatrogenic radial nerve palsy included distal location of fracture (P = 0.04, odds ratio 3.71) and previous fixation (P = 0.03, odds ratio 3.80). Of the 25 iatrogenic nerve injuries, 22 recovered fully with expectant management, 1 was lost to follow-up, and 2 required either nerve graft or tendon transfers. CONCLUSIONS: Time from injury to surgery does not seem to be a risk factor for developing an iatrogenic radial nerve palsy when treating diaphyseal humerus fractures. Patients with distal fractures, and those with previous fracture implants, are at increased risk of iatrogenic radial nerve palsy. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Predictors of Carpal Tunnel Release After Open Distal Radius Fracture.

The purpose of this investigation was to determine the incidence and identify the predictors of carpal tunnel release (CTR) after open fractures of the distal radius (DRF). Patients with clinical symptoms of persistent median nerve neuropathy that required CTR were analyzed for risk factors. One hundred thirty-nine open DRFs (107 grade I, 23 grade II, 9 grade III) met the inclusion criteria. The incidence of CTR was 13.7% in all open DRFs (19 out of 139). Multivariable logistic regression analysis identified four predictors: male sex [odds ratio (OR) = 8.8, p = .001], type III Gustilo and Anderson grade (OR = 6.2, p = .04), OTA fracture type C (OR = 3.8, p = .03), and the application of external fixation (OR = 14.0, p D .02). The probability of CTR, determined by preoperative variables, was 80% with three factors present and 2% with no risk factors. High-risk patients may be identified who may benefit from closer perioperative surveillance and possibly carpal tunnel release. (Journal of Surgical Orthopaedic Advances 26(4):227-232, 2017).

Mortality Following Surgical Management of Vancouver B Periprosthetic Fractures.

OBJECTIVES: The goals of this study are to evaluate mortality after Vancouver B periprosthetic fractures and determine predictors of mortality; compare mortality among patients with loose femoral stems treated with revision arthroplasty versus fixation alone; compare mortality among patients with radiographically "indeterminate" fractures treated with revision or fixation; and evaluate the rate of return to surgery for patients who underwent revision compared with fixation. DESIGN: Retrospective study. SETTING: Three academic level 1 trauma centers. PATIENTS/PARTICIPANTS: Two hundred three patients treated for Vancouver B periprosthetic fractures. INTERVENTION: N/A. MAIN OUTCOME MEASUREMENTS: The primary outcome measure was mortality. The secondary outcome measure was reoperation because of infection, failure of fixation, dislocation, or other mechanical failure. RESULTS: Overall 1-year survival was 87% and 5-year survival was 54%. Among patients with loose femoral stems, there was no significant difference with regard to survival between patients treated with fracture fixation or revision arthroplasty (1-year survival 83% vs. 85%, 5-year survival 41% vs. 58%). Among patients whose radiographs were classified as indeterminate, there was no significant difference between patients treated with fracture fixation alone or revision arthroplasty. There was no significant difference between total reoperation rates between the two groups (11% vs. 16%). CONCLUSION: This study suggests that there is no discernible survival benefit to treating patients with periprosthetic fractures with either revision arthroplasty or fixation alone. Therefore, from a mortality perspective, when faced with Vancouver B periprosthetic fractures, the orthopaedic surgeon should feel comfortable performing the type of intervention he/she is most proficient to perform. LEVEL OF EVIDENCE: Prognostic level III. See Instructions for Authors for a complete description of levels of evidence.

Intra-articular dexamethasone to inhibit the development of post-traumatic osteoarthritis.

Injury to the joint provokes a number of local pathophysiological changes, including synthesis of inflammatory cytokines, death of chondrocytes, breakdown of the extra-cellular matrix of cartilage, and reduced synthesis of matrix macromolecules. These processes combine to engender the subsequent development of post-traumatic osteoarthritis (PTOA). To prevent this from happening, it is necessary to inhibit these disparate responses to injury; given their heterogeneity, this is challenging. However, dexamethasone has the necessary pleiotropic properties required of a drug for this purpose. Using in vitro models, we have shown that low doses of dexamethasone sustain the synthesis of cartilage proteoglycans while inhibiting their breakdown after injurious compression in the presence or absence of inflammatory cytokines. Under these conditions, dexamethasone is non-toxic and maintains the viability of chondrocytes exposed chronically to such cytokines as interleukin (IL) -1, IL-6, and tumor necrosis factor-α. Moreover, the anti-inflammatory properties of dexamethasone have been appreciated for decades. In view of this information, we have initiated a pilot clinical study to determine whether a single, intra-articular injection of dexamethasone into the wrist shows promise in preventing PTOA after intra-articular fracture of the distal radius. CLINICAL SIGNIFICANCE: Suppressing the various etiopathophysiological responses to injury in the joint is an attractive strategy for lowering the clinical burden of PTOA. The intra-articular administration of dexamethasone soon after injury offers a simple and inexpensive means of accomplishing this. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:406-411, 2017.

Is Disuse Osteopenia a Favorable Prognostic Sign After Femoral Neck Fracture?

OBJECTIVES: Avascular necrosis (AVN) of the femoral head is a devastating complication following fixation of femoral neck fractures in younger adults. In this study, we investigate the prognostic utility of disuse osteopenia. DESIGN: Retrospective study. SETTING: Three academic Level 1 trauma centers. PATIENTS: One hundred twenty patients younger than 60 years treated for a femoral neck fracture. INTERVENTION: N/A. MAIN OUTCOME MEASURES: The presence of sclerosis or osteopenia, compared to the contralateral femoral head, was measured 6 weeks from injury both subjectively and using a novel radiographic measure, the relative density ratio (RDR). The outcome measure was radiographic development of AVN. RESULTS: The presence of relative sclerosis was associated with AVN and overall treatment failure. Patients with subjective relative sclerosis had a 12.6 (95% confidence interval, 2.9-61.3; P < 0.001) times higher odds of developing AVN. Multiple logistic regression showed that for every 0.10 increase in the RDR, there was a 5.2 increase in the odds (95% confidence interval, 2.1-26.9; P = 0.009) of developing AVN. Patients with an RDR of ≥1.2 have an 80% probability of AVN, whereas those with an RDR ≤0.8 have a <1% probability of developing AVN. CONCLUSIONS: Disuse osteopenia detected on 6-week radiographs is a favorable prognostic sign following fixation of femoral neck fractures. Patients who have relative sclerosis of the femoral head at 6-week follow-up are at a higher risk of developing AVN. LEVEL OF EVIDENCE: Diagnostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Interaction between living bone particles and rhBMP-2 in large segmental defect healing in the rat femur.

Orthopedic surgeons sometimes combine recombinant, human BMP-2 with autograft bone when dealing with problematic osseous fractures. Although some case reports indicate success with this off-label strategy, there have been no randomized controlled trials. Moreover, a literature search revealed only one pre-clinical study and this was in a cranial defect model. The present project examined the consequences of combining BMP-2 with particles of living bone in a rat femoral defect model. Human bone particles were recovered with a reamer-irrigator-aspirator (RIA). To allow acceptance of the xenograft as surrogate autograft, rats were administered an immunosuppressive cocktail that does not interfere with bone healing. Implantation of 200 µg living bone particles generated a small amount of new bone and defects did not heal. Graded amounts of BMP-2 that alone provoked no healing (1.1 µg), borderline healing (5.5 µg), or full healing (11 µg) were added to this amount of bone particles. Addition of BMP-2 (1.1 µg) increased osteogenesis, and produced bridging in 2 of 7 defects. The combination of BMP-2 (5.5 µg) and bone particles made healing more reliable and advanced the maturation of the regenerate. Bone formation with BMP-2 (11 µg) and bone particles showed improved maturation. Thus, the combination of autograft and BMP-2 may be helpful clinically under conditions where the healing response is suboptimal. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:2137-2145, 2016. Clinical significance These data support the clinical use of recombinant, human BMP-2 with autograft bone when treating large segmental osseous defects. The combination leads to greater bone formation and accelerates the maturation of the regenerate.