Zoledronic acid is more efficient than ibandronic acid in the treatment of symptomatic bone marrow lesions of the knee.

PURPOSE: The purpose of this study was to determine the efficacy and tolerability of different antiresorptive therapeutic regimens for treating symptomatic bone marrow lesions (BML) of the knee. METHODS: Patient records of 34 patients with radiologically diagnosed, painful BML of the knee treated with either a bisphosphonate (zoledronic, ibandronic, or alendronic acid) or with a human monoclonal antibody (denosumab) were retrospectively evaluated. Response to treatment was assessed, as change in patient-reported pain, by evaluation of BML expansion on MRI using the Whole-Organ Magnetic Resonance Imaging Score (WORMS), and by laboratory analysis of bone turnover markers: C-terminal cross-linking telopeptide (CTx) and procollagen type 1 amino-terminal propeptide (P1NP). Tolerability was evaluated by documentation of adverse reactions. RESULTS: Zoledronic acid was more or at least equally effective as the other treatment regimens with response to treatment in 11 of 12 patients (92%). The highest rate of adverse events was noted in 4 of 12 patients (33%) treated with zoledronic acid. CTx and WORMS differentiated well between responders and non-responders, whereas P1NP failed to do so. Changes in pain correlated moderately with change in WORMS (r = - 0.32), weakly with change in CTx (r = - 0.07), and not at all with change in P1NP. CONCLUSION: Zoledronic acid appeared to be more effective than other antiresorptive medications-at the cost of more frequent adverse events. While radiological and laboratory evaluation methods may allow for objective treatment monitoring, they appear to capture different dimensions than patient-reported pain. LEVEL OF EVIDENCE: III.

High rate of maintaining self-dependence and low complication rate with a new treatment algorithm for proximal humeral fractures in the elderly population.

BACKGROUND: We modified our treatment algorithm for proximal humeral fractures in elderly patients in 2013 to a more conservative approach avoiding locking plates. This study assesses the impact of this change on patient self-dependence. METHODS: We carried out an observational comparative study including both retrospectively and prospectively collected data. For the former, 147 isolated proximal humeral fracture patients older than 65 years were treated between 2011 and 2013 at our hospital and included in a historical group. The revised treatment algorithm was applied in a similar non-concurrent, comparative patient group (n = 160) prospectively enrolled between 2015 and 2017. The primary outcome was any loss of self-dependence, with secondary outcomes including documentation of shoulder functional scores, quality of life, and adverse events. RESULTS: Historical and prospective patients had similar baseline characteristics. Nonoperative treatment was performed in 53 historical patients (36%) and 83 prospective patients (78%). Prospective patients were 1.6 times less likely to lose some level of self-dependence (risk ratio, 0.62; 95% confidence interval, 0.25-1.5; P = .292), and the local adverse event risk dropped from 12.2% to 5.7% (P = .078). Mean shoulder function and quality of life were similar between the 2 groups. CONCLUSION: By applying our revised algorithm, a higher proportion of elderly patients maintained their premorbid level of self-dependence and returned to their previous social environment.

Low acceptance of osteoanabolic therapy with parathyroid hormone in patients with fragility fracture of the pelvis in routine clinical practice: a retrospective observational cohort study.

INTRODUCTION: A recent randomized controlled trial has reported full patient compliance and no adverse events from therapy with parathyroid hormone (PTH) for osteoporosis and accelerated healing of fragility fractures of the pelvis. The purpose of the presented study was to evaluate if similar results can be achieved with comprehensive PTH therapy in routine clinical practice. We hypothesised that patients' burden of PTH therapy is underestimated in the literature. PATIENTS AND METHODS: Osteoanabolic PTH therapy was recommended to 79 patients suffering from an acute fragility fracture of the pelvis (FFP). Case finding, initiation of therapy and follow-up were performed by a fracture liaison service team. Primary outcome was PTH initiation rate. Secondary outcomes were implementation rate of alternative antiresorptive pharmaceutical therapy for osteoporosis and participation rate in a bone metabolic workup. Adverse events and effects potentially related to the therapy with bone-active drugs were documented as exploratory outcomes. RESULTS: Osteoanabolic PTH therapy as suggested was accepted by 32%, whereas antiresorptive therapy was implemented in another 14% of the patients. DEXA scans were available in 38% of the patients (+ 27% when compared to baseline). A bone-specific laboratory analysis was done in 18 patients, uncovering 7 pathological findings. Two patients terminated PTH therapy early because of side effects. CONCLUSION: The experiences with PTH therapy in FFP patients with respect to, implementation rate, frequency of side effects and of pathological findings in laboratory controls as reported from a previous RCT could not be reproduced in routine clinical practice.

Minimally invasive anterior muscle-sparing versus a transgluteal approach for hemiarthroplasty in femoral neck fractures-a prospective randomised controlled trial including 190 elderly patients.

BACKGROUND: The relevance of femoral neck fractures (FNFs) increases with the ageing of numerous societies, injury-related decline is observed in many patients. Treatment strategies have evolved towards primary joint replacement, but the impact of different approaches remains a matter of debate. The aim of this trial was to evaluate the benefit of an anterior minimally-invasive (AMIS) compared to a lateral Hardinge (LAT) approach for hemiarthroplasty in these oftentimes frail patients. METHODS: Four hundred thirty-nine patients were screened during the 44-months trial, aiming at the evaluation of 150 patients > 60 yrs. of age. Eligible patients were randomised using an online-tool with completely random assignment. As primary endpoint, early mobility, a predictor for long-term outcomes, was evaluated at 3 weeks via the "Timed up and go" test (TUG). Secondary endpoints included the Functional Independence Measure (FIM), pain, complications, one-year mobility and mortality. RESULTS: A total of 190 patients were randomised; both groups were comparable at baseline, with a predominance for frailty-associated factors in the AMIS-group. At 3 weeks, 146 patients were assessed for the primary outcome. There was a reduction in the median duration of TUG performance of 21.5% (CI [- 41.2,4.7], p = 0.104) in the AMIS-arm (i.e., improved mobility). This reduction was more pronounced in patients with signs of frailty or cognitive impairment. FIM scores increased on average by 6.7 points (CI [0.5-12.8], p = 0.037), pain measured on a 10-point visual analogue scale decreased on average by 0.7 points (CI: [- 1.4,0.0], p = 0.064). The requirement for blood transfusion was lower in the AMIS- group, the rate of complications comparable, with a higher rate of soft tissue complications in the LAT-group. The mortality was higher in the AMIS-group. CONCLUSION: These results, similar to previous reports, support the concept that in elderly patients at risk of frailty, the AMIS approach for hemiarthroplasty can be beneficial, since early mobilisation and pain reduction potentially reduce deconditioning, morbidity and loss of independence. The results are, however, influenced by a plethora of factors. Only improvements in every aspect of the therapeutic chain can lead to optimisation of treatment and improve outcomes in this growing patient population. TRIAL REGISTRATION: www.clinicaltrials.gov : NCT01408693 (registered August 3rd 2011).

The Penrod score: a prognostic instrument to balance an increasing geriatric fracture caseload with diminishing health care resources?

INTRODUCTION: Geriatric hip fracture patients are a highly heterogeneous collective, what distinctly aggravates the best possible treatment. Consequently, it is becoming more important to identify selection criteria that can distinguish those patients who can benefit the most from treatment in a geriatric fracture center. In our pilot study, we assessed the 2007 published Penrod score for its utility as a useful selection tool by prospectively comparing our own patient's outcome with the Penrod study. METHODS: 77 patients treated for geriatric hip fracture were preoperatively classified according to the Penrod score. Patients were divided into three clusters by age (1: <75 years, 2: 75-84 years, 3: ≥85 years). Clusters 2 and 3 were then classified according to their ability to perform activities of daily living (ADL's) and cognitive status (presence or absence of dementia). In 51 out of these 77 patients, the ability to perform ADLs could be assessed 6 months postoperatively and was compared with the Penrod scores. RESULTS: 58 % of cluster 1 patients were able to perform 4 ADLs independently 6 months postoperatively (52.9 % Penrod study). In clusters 2A and 3A, 48 and 50 %, respectively, were able to perform 4 ADLs independently, compared with 40.6 and 31.5 % (Penrod collective). 22 % of our patients in 2B performed all ADLs independently (3.6 % Penrod) and 25 % in cluster 3B (9.4 % Penrod). CONCLUSION: Our preliminary results support the prognostic value of the Penrod score in the treatment of geriatric hip fracture patients. With the help of the Penrod score, it may be possible to identify patients, who are expected to significantly profit from an intensified treatment in a geriatric fracture center (clusters 2B, 3A, and 3B). By utilizing this score, improved outcomes and simultaneously a more effective utilization of valuable health care resources could be achieved.

Intraoperative mechanical measurement of bone quality with the DensiProbe.

Reduced bone stock can result in fractures that mostly occur in the spine, distal radius, and proximal femur. In case of operative treatment, osteoporosis is associated with an increased failure rate. To estimate implant anchorage, mechanical methods seem to be promising to measure bone strength intraoperatively. It has been shown that the mechanical peak torque correlates with the local bone mineral density and screw failure load in hip, hindfoot, humerus, and spine in vitro. One device to measure mechanical peak torque is the DensiProbe (AO Research Institute, Davos, Switzerland). The device has shown its effectiveness in mechanical peak torque measurement in mechanical testing setups for the use in hip, hindfoot, and spine. In all studies, the correlation of mechanical torque measurement and local bone mineral density and screw failure load could be shown. It allows the surgeon to judge local bone strength intraoperatively directly at the region of interest and gives valuable information if additional augmentation is needed. We summarize methods of this new technique, its advantages and limitations, and give an overview of actual and possible future applications.

Radiographic quantification of dynamic hip screw migration.

PURPOSE: This study aimed to propose a technique to quantify dynamic hip screw (DHS®) migration on serial anteroposterior (AP) radiographs by accounting for femoral rotation and flexion. METHODS: Femoral rotation and flexion were estimated using radiographic projections of the DHS® plate thickness and length, respectively. The method accuracy was evaluated using a synthetic femur fixed with a DHS® and positioned at pre-defined rotation and flexion settings. Standardised measurements of DHS® migration were trigonometrically adjusted for femoral rotation and flexion, and compared with unadjusted estimates in 34 patients. RESULTS: The mean difference between the estimated and true femoral rotation and flexion values was 1.3° (95% CI 0.9-1.7°) and -3.0° (95% CI - 4.2° to -1.9°), respectively. Adjusted measurements of DHS® migration were significantly larger than unadjusted measurements (p = 0.045). CONCLUSION: The presented method allows quantification of DHS® migration with adequate bias correction due to femoral rotation and flexion.

Long PHILOS plate fixation in a series of humeral fractures.

AIM: The purpose of the article is to highlight a specific fracture pattern encountered by us in the osteoporotic upper humerus. We present our results of management of such metadiaphyseal fractures of the upper humerus with less invasive plating. The additional steps taken to improve final outcome and the reasoning behind each are discussed. PATIENTS AND METHODS: In our department, a total of 13 fractures (in 12 patients) were managed for a metadiaphyseal fracture of the upper humerus between 2010 and 2013. There were 2 males and 10 females. The average age in the cohort was 74.3 (52-95) years. In 9 fractures, the fracture line was extending above the surgical neck. All patients were managed with a locking compression plate (long PHILOS or LCP) using two approach windows (proximal deltopectoral and a distal anterior or lateral). Patients were evaluated for clinical outcome using the Quick DASH score and assessed for radiological union, complications or re-operations retrospectively. RESULTS: The mean follow-up was 14.3 months (4-36). All fractures were united, and there was no evidence of avascular necrosis or non-union. Two patients showed varus collapse of the anatomical head of which one patient needed change of screws at 12 weeks from index surgery. In patients, when a distal lateral window was used, 2 patients out of 4 had radial nerve palsy post-operatively. In the rest, when the plate was twisted by 45° to allow anterior placement using the brachialis split, none had radial nerve injury. CONCLUSION: The osteoporotic bone failing under a low-energy mechanism seemed to dictate this fracture pattern. The fracture is either a bending wedge or a long spiral with or without a large butterfly and often extends into the humeral head. The fractures are better managed surgically, a primary reduction allowing contact of fragments is essential, and using an anterior window distally with a 45° contoured plate will achieve good plate placement as well as decreases the risk of radial nerve injury considerably compared to total lateral plate positioning.

[Do All Very Old Patients Benefit from Osteoporosis Drug Treatment?]

INTRODUCTION: Osteoanabolic osteoporosis drugs have become better available. The osteoanabolic therapeutic principle has a stronger, faster-onset fracture-reducing effect than the antiresorptive preparations. It has also been newly recognized that the significance of a first fragility fracture as a risk factor is time-dependent: the less time that has elapsed since the first fracture, the higher the resulting re-fracture risk. Patients older than 65 years whose index fragility fracture occurred less than two years before are therefore grouped in a separate "Imminent Fracture Risk" category. These innovations were implemented by updating the osteoporosis therapy guideline. According to this guideline, patients in the "Imminent Fracture Risk" category should be offered osteoporosis therapy as soon as possible, in order to avoid as many fractures as possible. We are critical of an overly strict implementation of this algorithm in very old fracture patients. Our own data indicate that more than 30 % of this subpopulation do not experience the effect of a newly started osteoporosis therapy. We advocate a clinically based indication for osteoporosis therapy. For this, we propose a "Question Surprise" modified for osteological purposes. "Would I be surprised if I had to treat the same patient for a fracture again in a year?" If the question is answered with "No," then that patient could be a candidate for specific osteoporosis treatment.

Technical comment on: Ferrari S, et al. 2020 recommendations for osteoporosis treatment according to fracture risk from the Swiss Association against Osteoporosis (SVGO).

No abstract available.

[Postoperative course following open reduction and internal fixation of fractures]. / Postoperative Betreuung nach operativer Frakturbehandlung.

The postoperative management after open reduction and internal fixation (ORIF) of fractures is addressed with this article. The topics selected focus on topics that are of relevance for the family practitioner. Because of large differences in the treatment of adult - and geriatric fracture patients these two groups are separately looked at in Part 1 and Part 2 of the article. Fractures in children or fractures of the growing skeleton are not addressed. In the early postoperative phase, the fracture patient might seek for advice in case of complications, such as wound infection or complex regional pain syndrome (CRPS). After fracture healing, the decision on implant removal has to be made. Geriatric fracture patients mostly cannot return back home directly from the hospital. Instead they are transferred to a rehabilitation center. In these patients secondary fracture prevention should be in the focus of the family practitioner. This means osteoporosis diagnostics and treatment shall be initiated, if not done before. Another important task is to guarantee for compliance with the therapy once it is initiated.

Hip fracture management, before and beyond surgery and medication: a synthesis of the evidence.

INTRODUCTION: The geriatrician and orthopedic surgeon's roles are well defined in hip fracture management, yet other health-care providers contribute significantly toward care, as well as maximizing rehabilitation potential and decreasing readmissions. We examine evidence concerning pre-hospital care, pain management, multidisciplinary rehabilitation and secondary prevention strategies. METHODS: Cochrane reviews and randomized controlled trials were identified through PubMed to synthesize current evidence in the role of multidisciplinary management of the patient with a hip fracture from injury to secondary prevention. The well-recognized roles of the geriatrician, anesthetist and orthopedic surgeon were not evaluated for the purpose of this review. RESULTS: Transport of patients with a hip fracture can be eased through non-pharmaceutical simple, inexpensive techniques. Nerve blockade appears effective and easily administered in the emergency department. In-hospital multidisciplinary rehabilitation programs are effective in both earlier discharge and reducing falls, morbidity and mortality. Fall prevention programs are effective in nursing home patients, but not community dwellers. Osteoporosis prevention is primarily a medical endeavor; however, exercise and education may contribute to increased bone mineral density, compliance and better results of treatment. CONCLUSION: Multidisciplinary medical management of patients with hip fractures is being improved within the hospital environment resulting in earlier discharge with decreased morbidity. There is evidence to show the benefits to patients with hip fractures from peripheral modalities within the hospital; however unless resident in a facility, multidisciplinary management is not clearly of benefit.

Scope and Limits of Teriparatide Use in Delayed and Nonunions: A Case Series.

Nonunion is known to occur in up to 10% of all bone fractures. Until recently, the treatment options considered in cases of delayed union and nonunion focused on revision surgery and improvement of local healing. Lately, teriparatide has been introduced as an osteoanabolic factor that induces fracture healing in cases with delayed or nonunions. We report on a series of five cases of delayed and nonunions treated with teriparatide: delayed unions of an atypical femoral fracture, of a multifragmentary clavicle fracture, and of a periprosthetic humeral fracture; nonunion of a tibial and fibular fracture; and infected nonunion of a tibial and fibular fracture. Based on this series, the indications and limits of application of teriparatide in cases of impaired fracture healing are discussed. Due to the "off-label" character of this application, informed consent, and cost coverage from the healthcare insurance must be obtained prior to treatment. In our experience and according to the limited existing literature, teriparatide is a safe feasible treatment in cases of delayed and nonunions with a reasonable need of resources. While adequate biomechanical stability remains the cornerstone of fracture healing, as well as healing of nonunions, teriparatide could help avoid repetitive surgeries, especially in atrophic delayed and nonunions, as well as in patients with impaired fracture healing undergoing bisphosphonate therapy. There is an urgent need for widely accepted definitions, standardized protocols, as well as further clinical trials in the field of impaired fracture healing.

Management of fragility fractures in Switzerland: results of a nationwide survey.

A nationwide survey was conducted in Switzerland to assess the quality level of osteoporosis management in patients aged 50 years or older presenting with a fragility fracture to the emergency ward of the participating hospitals. Eight centres recruited 4966 consecutive patients who presented with one or more fractures between 2004 and 2006. Of these, 3667 (2797 women, 73.8 years old and 870 men, 73.0 years old in average) were considered as having a fragility fracture and included in the survey. Included patients presented with a fracture of the upper limbs (30.7%), lower limbs (26.4%), axial skeleton (19.5%) or another localisation, including malleolar fractures (23.4%). Thirty-two percent reported one or more previous fractures during adulthood. Of the 2941 (80.2%) hospitalised women and men, only half returned home after discharge. During diagnostic workup, dual x-ray absorptiometry (DXA) measurement was performed in 31.4% of the patients only. Of those 46.0% had a T-score < or =-2.5 SD and 81.1% < or =-1.0 SD. Osteoporosis treatment rate increased from 26.3% before fracture to 46.9% after fracture in women and from 13.0% to 30.3% in men. However, only 24.0% of the women and 13.8% of the men were finally adequately treated with a bone active substance, generally an oral bisphosphonate, with or without calcium / vitamin D supplements. A positive history of previous fracture vs none increased the likelihood of getting treatment with a bone active substance (36.6 vs 17.9%, ? 18.7%, 95% CI 15.1 to 22.3, and 22.6 vs 9.9%, ? 12.7%, CI 7.3 to 18.5, in women and men, respectively). In Switzerland, osteoporosis remains underdiagnosed and undertreated in patients aged 50 years and older presenting with a fragility fracture.

Navigating the fluoroscope's C-arm back into position: an accurate and practicable solution to cut radiation and optimize intraoperative workflow.

OBJECTIVES: During complex image-guided orthopedic trauma procedures, repetitive fluoroscopic scout imaging is performed. A number of preparatory positioning images often must be taken to reproduce a comparable projection. These scout images have no intrinsic clinical relevance but nevertheless expose the patient and the surgical team to considerable radiation, which could be avoided. This study presents and validates a method to decrease intraoperative radiation. METHODS: Precision, time requirements, and number of scout images for repositioning the fluoroscope, with and without navigation aid, were recorded on 20 test-rig and 3 phantom setups. A commercially available image-guided surgical navigation system (Vector Vision, BrainLAB), originally designed for instrument navigation, was employed to register and retrieve the C-arm positions. A newly developed software computed the necessary moves to reposition the C-arm on an intuitive visual display. RESULTS: Retrieving a given C-arm position with the conventional non-navigated technique required an average of 7 scout images (range, 3 to 12 images). In contrast, navigation-assisted repositioning did not necessitate a single scout image. Deviations from the original projection were minimal for both navigated (0.9 degrees, 95% CI 0.8 to 1.1 degrees) and non-navigated repositioning (0.8 degrees, 95% CI 0.7 to 0.9 degrees). Average positioning times were comparable when navigating the C-arm (46 seconds, 95% CI 41 to 51 seconds) and in scout image-based positioning (49 seconds, 95% CI 44 to 53 seconds). CONCLUSIONS: Navigated C-arm positioning avoids multiple scout images and yields sufficient precision for clinical deployment. Radiation exposure can be reduced considerably by a combination of instrument navigation and navigated C-arm positioning.

Good functional outcome in patients suffering fragility fractures of the pelvis treated with percutaneous screw stabilisation: Assessment of complications and factors influencing failure.

BACKGROUND: Low energy pelvic ring fractures in the elderly have traditionally been treated conservatively, a treatment with potential long-term complications and loss of self-independence. Percutaneous screw stabilisation of the posterior pelvic ring is a new treatment modality that enables immediate mobilisation. The aim of this study was to assess the functional outcome after sacroiliac stabilisation in the elderly. METHODS: All elderly patients with a surgically stabilised low energy pelvic fracture between 2010 and 2015 were included. In 2016 a radiographic follow up and functional test was performed at least one year postoperative. RESULTS: The 50 operated patients had a mean age of 79 years and a one-year mortality of 10% (5/50). Only six patients lost independency after the pelvic fracture and moved to nursing home. The mean Timed Up and Go test was 16s at follow-up. The operation of the posterior pelvic ring averaged 63min with a radiation equal to a diagnostic pelvic CT. One intra-foraminally placed screw was immediately removed and 9 patients were later re-operated on due to symptomatic loosening of one or more screws. No loosening of screws was seen in 11 patients where both S1 and S2 were stabilised and out of 23 trans-sacral screws (crossing both sacroiliac joints) only two loosened. DISCUSSION: CT guided stabilisation of the posterior pelvis is safe and most patients resumed good function and independent living. The risk of a revision operation was 20%, but trans-sacral screw stabilisation in both S1 and S2 could reduce the risk of implant loosening.

Osteoporosis drug treatment: duration and management after discontinuation. A position statement from the SVGO/ASCO.

Antiosteoporotic drugs are recommended in patients with fragility fractures and in patients considered to be at high fracture risk on the basis of clinical risk factors and/or low bone mineral density. As first-line treatment most patients are started with an antiresorptive treatment, i.e. drugs that inhibit osteoclast development and/or function (bisphosphonates, denosumab, oestrogens or selective oestrogen receptor modulators). In the balance between benefits and risks of antiresorptive treatment, uncertainties remain regarding the optimal treatment duration and the management of patients after drug discontinuation. Based on the available evidence, this position statement will focus on the long-term management of osteoporosis therapy, formulating decision criteria for clinical practice.

Displaced trochanteric fragments lead to poor functional outcome in pertrochanteric fractures treated by cephalomedullary nails.

BACKGROUND: The importance of the greater trochanter and its attached abductor muscles for physiological gait is well accepted. However the influence of a displaced greater trochanter fracture after a pertrochanteric fracture is unknown. The aim of this study is to determine if there is an association between the greater trochanter position and the level of patient mobility following internal fixation of pertrochanteric fractures. METHODS: One hundred and thirty-three consecutive elderly patients with a median age of 85 (interquartile range [IQR] 79-91) years, who were treated for pertrochanteric fractures at a level I trauma centre, were recruited. AO 31 A3.1 and A3.2 fracture types were excluded from the statistical analysis. Patient mobility was prospectively assessed before the fracture and one year following fracture treatment using the Parker mobility score. In a multivariable analysis, the influence of a displaced greater trochanter on patient mobility at one-year follow-up was assessed. The analysis was adjusted for age, gender, body mass index, Charlson comorbidity index, AO fracture classification, varus-/valgus malposition of the neck-shaft fragments, and Parker mobility score before fracture. RESULTS: Post-operative X-rays were available in 125 patients, out of which 66 (53%) patients were identified with a displaced or migrated greater trochanter. One year mortality rate was 22% (n=27). In the 82 patients who had functional assessment one year post-operatively, the median Parker mobility score before fracture and at one-year follow-up was 7 (IQR 4-9) and 7 (IQR 3-9) in patients without, and 7 (IQR 4-9) and 3 (IQR 2-5) in patients with a displaced greater trochanter. In multivariable analysis, a displaced greater trochanter was significantly associated with a lower Parker mobility score (-1.74, 95% confidence interval -2.37, -1.12, p<0.01). CONCLUSION: Greater trochanter displacement following internal fixation of extracapsular hip fractures with a cephalomedullary nail is associated with a poor functional outcome. Greater attention to achieve adequate reduction and stabilisation of this fragment during internal fixation of pertrochanteric hip fractures should be aimed for despite the inability of current cephalomedullary implants to do so. LEVEL OF EVIDENCE: III prognostic and epidemiological study.

Trabecular bone strength is not an independent predictive factor for dynamic hip screw migration--A prospective multicenter cohort study.

This study assessed whether mechanically measured trabecular bone strength is an independent predictor of dynamic hip screw (DHS) stability, i.e., DHS migration (DHSM) after the fixation of proximal femoral fractures. One-hundred and seven patients older than 50 years with proximal femoral fractures were included. During fracture fixation, a mechanical probe (DensiProbe™ Hip) was inserted at the site where the DHS tip would ultimately be positioned. Peak torque to breakaway the trabecular bone was measured. Fracture reduction, primary implant position and postoperative DHSM were assessed by radiographs taken postoperatively, at 6 and 12 weeks after surgery. Univariate regression analysis revealed no association between peak torque and DHSM (R(2) = 0.025, p = 0.135). DHSM correlated with the primary DHS position, i.e., the distance between the DHS and (i) the central femoral neck axis (CNFAD, R(2) = 0.230; p < 0.0001) and (ii) the apex of the femoral head (R(2) = 0.110; p = 0.001). DHSM did not correlate with areal BMD of the contralateral proximal femur. Multivariable regression modeling revealed the CFNAD as predictive factor for screw migration. The primary implant position measured by the CFNAD, rather than DensiProbe™ Hip measured bone strength, is an independent predictor of DHSM.