Risk Of Postoperative Fracture Research Articles

410 Improving Patient Outcomes through Design of Biodegradable Implants for Long Bone Fractures

OBJECTIVES/GOALS: Current long bone fracture standard of care uses inert metal intramedullary nails (IMN), 10x stiffer than femur cortex. Consequent “stress-shielding” bone loss sees >5% of patients needing revision surgery. To improve nonunion healing, we develop automated design optimization methods for biodegradable Mg alloy IMNs to control local reloading. METHODS/STUDY POPULATION: Finite element analysis (FEA) is performed on 3D bone-IMN representations to establish this study’s baseline strain states for existing inert IMN geometries within QCT-informed femoral models under simulated biomechanical loading. FEA with Mg alloy properties for same IMN designs simulate transient IMN material loss through discrete time-step models with experimental in vivo Mg corrosion rates and strain-based bone density evolution using remodeling algorithms from literature. Transient stability and strength metrics, fracture zone stress profiles under gradual reloading and manufacturing constraints are formulated through gradient-based sensitivity analysis into a topology optimization framework (TOF) incorporating a reaction-diffusion degradation model to generate IMN topologies. RESULTS/ANTICIPATED RESULTS: TOF designs for Mg alloy IMNs with transient allowable strength constraints, using safety factors to prevent IMN failure, demonstrate higher compliance than standard inert IMNs with mechanical properties closer to native cortical bone. The biodegradation model within the TOF, informed by corrosion behavior from bone-IMN FEA study, predicts how potential design evolutions affect transient strain states of the system. Thus, local fracture region stress states are controlled by the algorithm optimizing for desirable transient stiffness profiles based on a minimum variance objective of fracture zone stress compared to a target bone stress profile. Optimized IMNs with porous, high surface area features achieve 50% decrease in IMN stiffness over 6 months recovery time and complete in vivo degradation in 24 months. DISCUSSION/SIGNIFICANCE: Our TOF reduces “stress-shielding” effects via design for controlled IMN biodegradation to gradually increase fracture zone loading, stimulating remodeling and reducing current risk of post-operative fracture and surgical removal in ~15k cases/yr. in the U.S. In vitro mechanical and in vivo clinical testing is required to validate design results.

Fracture risk after intralesional curettage of atypical cartilaginous tumors

IntroductionThe need for curettage of atypical cartilaginous tumors (ACT) is under debate. Curretage results in defects that weaken the bone potentially leading to fractures. The purpose of this study was to retrospectively determine postoperative fracture risk after curettage of chondroid tumors, including patient-specific characteristics that could influence fracture risk.MethodsA total of 297 adult patients who underwent curettage of an ACT followed by phenolisation and augmentation were retrospectively evaluated. Explanatory variables were, sex, age, tumor size, location, augmentation type, and plate fixation. The presence of a postoperative fracture was radiologically diagnosed. Included patients had at least 90 days of follow-up.ResultsA total of 183 females (62%) were included and 114 males (38%), with an overall median follow-up of 3.2 years (IQR 1.6–5.2). Mean diameter of the lesions was 4.5 (SD 2.8) cm. Patients received augmentation with allograft bone (n = 259, 87%), PMMA (n = 11, 3.7%), or did not receive augmentation (n = 27, 9.1%). Overall fracture risk was 6%. Male sex (p = 0.021) and lesion size larger than 3.8 cm (p < 0.010) were risk factors for postoperative fracture.InterpretationCurettage of ACT results in an overall fracture risk of 6%, which is increased for males with larger lesions.

Intradiscal cement leakage (ICL) increases the stress on adjacent vertebrae after kyphoplasty for osteoporotic vertebra compression fracture (OVCF): a finite-element study

This study aimed to explore the biomechanical effects on adjacent vertebra of thoracolumbar Osteoporotic Vertebra Compression Fracture (OVCF) after Percutaneous Kyphoplasty (PKP) with intraoperative intradiscal cement leakage (ICL) by applying a Finite-Element Analysis. We collected pre- and post-operative computer tomography (CT) images of a 71-year-old female patient with single T12 OVCF, who underwent an intraoperative cement leakage into the T12–L1 disc. Three-dimensional finite element models of thoracolumbar spine (T10–L2) were built with the support of Materialise Interactive Medical Image Control System (MIMICS) and ABAQUS software. The stress on adjacent vertebrae and endplates under the uniform compressive pressure (0.3 MPa) and during different loading moments were analyzed. The three-dimensional finite element models reveal an asymmetrical distribution of von Mises stresses on the adjacent endplate unaffected by the surgical intervention. The maximum von Mises stress on adjacent vertebral bodies increased during different loading conditions, especially for lateral bending and rotation loading conditions, whereas the maximum von Mises stress on distal non-treated vertebrae decreased on anteflexion and backward extension loading conditions. Post-operative adjacent vertebra compression fractures after PKP with intraoperative intradiscal cement leakage (ICL) may be closely related to the biomechanical changes of adjacent vertebrae of thoracolumbar OVCF, and it may increase the risk of postoperative fracture.

Risk factors of fracture following curettage for bone giant cell tumors of the extremities

BackgroundFollowing curettage of giant cell tumor of bone (GCTB), it is common to fill the cavity with polymethylmethacrylate (PMMA) bone cement, bone allograft, or artificial bone to maintain bone strength; however, there is a 2–14% risk of postoperative fractures. We conducted this retrospective study to clarify the risk factors for fractures after curettage for GCTB of the extremities.MethodsThis study included 284 patients with GCTBs of the extremities who underwent curettage at our institutions between 1980 and 2018 after excluding patients whose cavities were not filled with anything or who had additional plate fixation. The tumor cavity was filled with PMMA bone cement alone (n = 124), PMMA bone cement and bone allograft (n = 81), bone allograft alone (n = 63), or hydroxyapatite graft alone (n = 16).ResultsFractures after curettage occurred in 10 (3.5%) patients, and the median time from the curettage to fracture was 3.5 months (interquartile range [IQR], 1.8–8.3 months). The median postoperative follow-up period was 86.5 months (IQR, 50.3–118.8 months). On univariate analysis, patients who had GCTB of the proximal or distal femur (1-year fracture-free survival, 92.5%; 95% confidence interval [CI]: 85.8–96.2) presented a higher risk for postoperative fracture than those who had GCTB at another site (100%; p = 0.0005). Patients with a pathological fracture at presentation (1-year fracture-free survival, 88.2%; 95% CI: 63.2–97.0) presented a higher risk for postoperative fracture than those without a pathological fracture at presentation (97.8%; 95% CI: 95.1–99.0; p = 0.048). Patients who received bone grafting (1-year fracture-free survival, 99.4%; 95% CI: 95.7–99.9) had a lower risk of postoperative fracture than those who did not receive bone grafting (94.4%; 95% CI: 88.7–97.3; p = 0.003).ConclusionsFor GCTBs of the femur, especially those with pathological fracture at presentation, bone grafting after curettage is recommended to reduce the risk of postoperative fracture. Additional plate fixation should be considered when curettage and cement filling without bone grafting are performed in patients with GCTB of the femur. This should be specially performed for those patients with a pathological fracture at presentation.

A Three-Dimensional Cement Quantification Method for Decision Prediction of Vertebral Recompression after Vertebroplasty.

Objective Proposing parameters to quantify cement distribution and increasing accuracy for decision prediction of vertebroplasty postoperative complication. Methods Finite element analysis was used to biomechanically assess vertebral mechanics (n = 51) after percutaneous vertebroplasty (PVP) or kyphoplasty (PKP). The vertebral space was divided into 27 portions. The numbers of cement occupied portions and numbers of cement-endplate contact portions were defined as overall distribution number (oDN) and overall endplate contact number (oEP), respectively. And cement distribution was parametrized by oDN and oEP. The determination coefficients of vertebral mechanics and parameters (R2) can validate the correlation of proposed parameters with vertebral mechanics. Results oDN and oEP were mainly correlated with failure load (R2 = 0.729) and stiffness (R2 = 0.684), respectively. oDN, oEP, failure load, and stiffness had obvious difference between the PVP group and the PKP group (P < 0.05). The regional endplate contact number in the front column is most correlated with vertebral stiffness (R2 = 0.59) among all regional parameters. Cement volume and volume fraction are not dominant factors of vertebral augmentation, and they are not suitable for postoperative fracture risk prediction. Conclusions Proposed parameters with high correlation on vertebral mechanics are promising for clinical utility. The oDN and oEP can strongly affect augmented vertebral mechanics thus is suitable for postoperative fracture risk prediction. The parameters are beneficial for decision-making process of revision surgery necessity. Parametrized methods are also favorable for surgeon's preoperative planning. The methods can be inspirational for clinical image recognition development and auxiliary diagnosis.

Bariatric surgery increases the rate of major fracture: self-controlled case series study in UK Clinical Practice Research Datalink.

ABSTRACTConflicting results exist about the relationship between bariatric surgery and fracture risk. Also, prediction of who is at increased risk of fracture after bariatric surgery is not currently available. Hence, we used a combination of a self‐controlled case series (SCCS) study to establish the association between bariatric surgery and fracture, and develop a prediction model for postoperative fracture risk estimation using a cohort study. Patients from UK Primary care records from the Clinical Practice Research Datalink GOLD linked to Hospital Episode Statistics undergoing bariatric surgery with body mass index (BMI) ≥30 kg/m2 between 1997 and 2018 were included in the cohort. Those sustaining one or more fractures in the 5 years before or after surgery were included in the SCCS. Fractures were considered in three categories: (i) any except skull and digits (primary outcome); (ii) major (hip, vertebrae, wrist/forearm, and humerus); and (iii) peripheral (forearm and lower leg). Of 5487 participants, 252 (4.6%) experienced 272 fractures (of which 80 were major and 135 peripheral) and were included in the SCCS analyses. Major fracture risk increased after surgery, incidence rate ratios (IRRs) and 95% confidence intervals (CIs): 2.77 (95% CI, 1.34–5.75) and 3.78 (95% CI, 1.42–10.08) at ≤3 years and 3.1 to 5 years postsurgery when compared to 5 years prior to surgery, respectively. Any fracture risk was higher only in the 2.1 to 5 years following surgery (IRR 1.73; 95% CI, 1.08–2.77) when compared to 5 years prior to surgery. No excess risk of peripheral fracture after surgery was identified. A prediction tool for major fracture was developed using 5487 participants included in the cohort study. It was also internally validated (area under the receiver‐operating characteristic curve [AUC ROC] 0.70) with use of anxiolytics/sedatives/hypnotics and female as major predictors. Hence, major fractures are nearly threefold more likely after bariatric surgery. A simple prediction tool with five variables identifies high risk patients for major fracture. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Post-operative fracture risk assessment following tumor curettage in the distal femur: a hybrid in vitro and in silico biomechanical approach

The distal femur is the predominant site for benign bone tumours and a common site for fracture following tumour removal or cementation. However, the lack of conclusive assessment criterion for post-operative fracture risk and appropriate devices for cement augmentation are serious concerns. Hence, a validated biomechanical tool was developed to assess bone strength, depending on the size and location of artificially created tumorous defects in the distal femora. The mechanics of the bone–cement interface was investigated to determine the main causes of reconstruction failure. Based on quantitative-CT images, non-linear and heterogeneous finite element (FE) models of human cadaveric distal femora with simulated tumourous defects were created and validated using in vitro mechanical tests from 14 cadaveric samples. Statistical analyses demonstrated a strong linear relationship (R2 = 0.95, slope = 1.12) with no significant difference between bone strengths predicted by in silico analyses and in vitro tests (P = 0.174). FE analyses showed little reduction in bone strength until the defect was 35% or more of epiphyseal volume, and reduction in bone strength was less pronounced for laterally located defects than medial side defects. Moreover, the proximal end of the cortical window and the most interior wall of the bone–cement interface were the most vulnerable sites for reconstruction failure.

The Medial Eminence Line for Predicting Tibial Fracture Risk after Unicompartmental Knee Arthroplasty.

BackgroudTibial fracture after cementless Oxford unicompartmental knee arthroplasty (OUKA) is a rare but serious complication. It is reported more frequently in Asian countries. The aim of this retrospective study was to assess the morphological characteristics of the tibia by using a simple novel measurement method in patients with tibial fractures after OUKA.MethodsSix knees (all women) with tibial fractures after cementless OUKA (fracture group) and 150 knees without an obvious complication after cementless OUKA (control group) were examined retrospectively at our institution between January 2016 and April 2017. We drew a medial eminence line (ME line) defined as a line extending from the tip of the medial intercondylar eminence parallel to the tibial axis. The ME line was classified into two types (intramedullary type [type I] and extramedullary type [type E]), and the proportion of each type was compared between fracture patients and controls.ResultsIn the fracture group, there were four (66.7%) type E cases and two (33.3%) type I cases; in the control group, there were 18 (12%) type E cases and 132 (88%) type I cases. Fisher exact tests showed that the proportion of type E was higher in the fracture group than in the control group (p < 0.01).ConclusionsMeasurement of the ME line can be recommended as a useful method to assess the risk of postoperative fracture after cementless OUKA.

Investigation on distal femoral strength and reconstruction failure following curettage and cementation: In-vitro tests with finite element analyses

Cement augmentation following benign bone tumor surgery, i.e. curettage and cementation, is recommended in patients at high risk of fracture. Nonetheless, identifying appropriate cases and devices for augmentation remains debatable. Our goal was to develop a validated biomechanical tool to: predict the post-surgery strength of a femoral bone, assess the precision and accuracy of the predicted strength, and discover the mechanisms of reconstruction failure, with the aim of finding a safe biomechanical fixation. Tumor surgery was mimicked in quantitative-CT (QCT) scanned cadaveric human distal femora, and subsequently tested in compression to measure bone strength (FExp). Finite element (FE) models considering bone material non-homogeneity and non-linearity were constructed to predict bone strength (FFE). Analyses of contact, damage, and crack initiation at the bone-cement interface (BCI) were completed to investigate critical failure locations. Results of paired t-tests did not show a significant difference between FExp and FFE (P > 0.05); linear regression analysis resulted in good correlation between FExp and FFE (R2 = 0.94). Evaluation of the models precision using linear regression analysis yielded R2 = 0.89, with the slope = 1.08 and intercept = −324.16 N. FE analyses showed the initiation of damage and crack and a larger cement debonding area at the proximal end and most interior part of BCI, respectively. Therefore, we speculated that devices that reinforce critical failure locations offer the most biomechanical advantage. The QCT-based FE method proved to be a reliable tool to predict distal femoral strength, identify some causes of reconstruction failure, and assist in a safer selection of fixation devices to reduce post-operative fracture risk.

Risk factors for intra-operative and post-operative fractures associated with primary total ankle replacement surgery - a data linkage study from the UK National Joint Registry

Category: Ankle Introduction/Purpose: Intra and post-operative fractures are recognised complications of total ankle replacement (TAR) surgery. Intra-operative fractures are captured on the National Joint Registry (NJR) in the UK. The NJR has been capturing data on ankle replacement surgery since April 2010 and the number of TARs on the register is approaching 4000. Post-operative fractures are captured in the Hospital Episodes Statistics (HES) database. HES stores all patients admitted to NHS hospitals in England and captures 125 million records each year. Diagnostic information is stored using the International Classification of Diseases (ICD) and operative details using the Office of Population, Censuses and Surveys Classification (OPCS) codes. The purpose of this work was to determine the rate of intra and post-operative fracture with primary TAR and determine risk factors. Methods: A data-linkage study of the UK National Joint Registry (NJR) data and Hospital Episodes Statistics (HES) database was peformed using the first 3 years of NJR data. These two databases were linked in a deterministic fashion. 1522 NJR records were linked with the HES data set of over 90 million records. 1110 records were able to linked and available for analysis. Unlinked NJR data was analysed to identify intra-operative fractures. Linked data was analysed to identify post-operative fractures using ICD codes. Logistic regression was used to model predictors of intra and post-operative fractures. Every model was adjusted for patient characteristics including age, BMI, comorbidity and ASA grade. Results: The rate of intra-operative fracture was 2.69% (95% CI 2.67% to 2.74%). When looking at patient characteristics no significant predictors emerged. Logistic regression adjusted for patient characteristics showed that patients with rheumatoid arthritis were twice as likely to have a intra-operative fractures. The rate of post-operative fracture in the 12 months following primary TAR was 1.08% (95% CI 1.05% to 1.14%). Age emerged as a risk factor with a 5 five fold increase in risk of post-operative fracture with age 65-74 compared with those below 65. Adjusted logistic regression showed an increase risk of post-operative fracture in rheumatoid patients, hybrid operations and with those with multiple concurrent procedures. The risk of fracture was doubled with one associated procedure and tripled with two procedures. Conclusion: The rate of intra and post-operative fracture associated with primary total ankle replacement is low. However care should be taken with patients over 65 as they are at greater risk of intra operative fractures. Patients with rheumatoid arthritis are at greater risk of both, likely due to the effect of drug treatment. All efforts should be made to review medications and bone protective medication prescribed for these patents when undergoing TAR.

Biomechanical Evaluation of Unicortical Stress Risers of the Proximal Humerus Associated With Pectoralis Major Repair.

Proximal humerus fracture after pectoralis major tendon repair has been recently reported. Although this complication is rare, it may be possible to decrease such risk using newer techniques for myotenodesis. This study was designed to evaluate various unicortical stress risers created at the proximal humeral metadiaphysis during myotenodesis for repair of pectoralis major ruptures. A simulated pectoralis major myotenodesis was performed using fourth-generation Sawbones (N=30). Using previously described anatomic landmarks for the tendinous insertion, 3 repair techniques were compared: bone trough, tenodesis screws, and suture anchors (N=10 each). Combined compression and torsional load was sequentially increased until failure. Linear and rotational displacement data were collected. The average number of cycles before reaching terminal failure was 383 for the bone trough group, 658 for the tenodesis group, and 832 for the suture anchor group. Both the tenodesis and the suture anchor groups were significantly more resistant to fracture than the bone trough group (P<.001). The suture anchor group was significantly more resistant to fracture than the tenodesis group (P<.001). All test constructs failed in rotational stability, producing spiral fractures, which incorporated the unicortical defects in all cases. When tested under physiologic parameters of axial compression and torsion, failure occurred from rotational force, producing spiral fractures, which incorporated the unicortical stress risers in all cases. The intramedullary suture anchor configuration proved to be the most stable construct under combined axial and torsional loading. Using a bone trough technique for proximal humerus myotenodesis may increase postoperative fracture risk. [Orthopedics. 2017; 40(5):e801-e805.].

What Are the Risk Factors and Complications Associated With Intraoperative and Postoperative Fractures in Total Wrist Arthroplasty?

Total wrist arthroplasty (TWA) can relieve pain and preserve some wrist motion in patients with advanced wrist arthritis. However, few studies have evaluated the risks and outcomes associated with periprosthetic fractures around TWAs. (1) What is the risk of intraoperative and postoperative fractures after TWAs? (2) What factors are associated with increased risk of intraoperative and postoperative fracture after TWAs? (3) What is the fracture-free and revision-free survivorship of TWAs among patients who sustained an intraoperative fracture during the index TWA? At one institution during a 40-year period, 445 patients underwent primary TWAs. Of those, 15 patients died before 2 years and 5 were lost to followup, leaving 425 patients who underwent primary TWAs with a minimum of 2-year followup. The primary diagnosis for the TWA included osteoarthritis ([OA] 5%), inflammatory arthritis (90%), and posttraumatic arthritis (5%). Indications for TWA included pancarpal arthritis combined with marked pain and loss of wrist function. The mean age of the patients was 57 years, BMI was 26kg/m2, and 73% were females. Six different implants were used during the 40-year period. Mean followup was 10 years (range, 2-18 years). Intraoperative fractures occurred in nine (2%) primary TWAs, while postoperative fractures occurred after eight (2%) TWAs. After analyzing demographics, comorbidities, and surgical factors, intraoperative fractures were found to be associated with only age at surgery (hazard ratio [HR], 1.10; 95% CI, 1.03-1.20; p = 0.006) and use of a bone graft (HR, 5.80; 95% CI, 1.18-23.08; p = 0.03). No factors were found to be associated with increased risk of postoperative fractures; specifically, intraoperative fracture was not associated with subsequent fracture development. The 5-, 10-, and 15-year Kaplan-Meier survival rates free of postoperative fracture were 99%, 98%, and 95%, respectively. The 5- and 10-year revision-free survival rates after intraoperative fracture were 88% and 88%, respectively, compared with 84% and 74% without an intraoperative fracture (p = 0.36). Furthermore, the survival-free of revision surgery rates for aseptic distal loosening at 5 and 10 years were 88% and 88%, respectively, compared with 93% and 87% without a fracture (p = 0.85). Intraoperative fractures occur in approximately 2% of TWAs. These fractures do not appear to affect long-term implant survival or risk of fracture. Patient age and the need for bone graft were the only factors in the risk of intraoperative fractures. Postoperative fractures also occur in 2% of TWAs, but often result in revision surgery. Level III, therapeutic study.

Lower limb arthroplasty: can we produce a tool to predict outcome and failure, and is it cost-effective? An epidemiological study

Lower limb arthroplasty: can we produce a tool to predict outcome and failure, and is it cost-effective? An epidemiological study

Effect of smoking on complications following primary shoulder arthroplasty

The purpose of this study was to examine the effect of smoking on the incidence of complications after primary anatomic total shoulder arthroplasty (TSA) and reverse shoulder arthroplasty (RSA). All patients who underwent primary TSA or RSA at our institution between 2002 and 2011 and had a minimum 2-year follow-up were included. Smoking status was assessed at the time of surgery. Current smokers, former smokers, and nonsmokers were compared for periprosthetic infection, fractures (intraoperative and postoperative), and loosening after surgery. The cohort included 1834 shoulders in 1614 patients (814 in smokers and 1020 in nonsmokers). Complications occurred in 73 patients (75 shoulders; 44 in smokers and 31 in nonsmokers). There were 20 periprosthetic infections (16 in smokers and 4 in nonsmokers), 27 periprosthetic fractures (14 in smokers and 13 in nonsmokers), and 28 loosenings (14 in smokers and 14 in nonsmokers). Smokers had lower periprosthetic infection-free survival rates (95.3%-99.4% at 10 years; P = .001) and overall complication-free survival rates (78.4%-90.2%; P = .012) than nonsmokers. Multivariable analyses showed that both current and former smokers had significantly higher risk of periprosthetic infection in comparison with nonsmokers (hazard ratio [HR], 7.27 and 4.56, respectively). In addition, current smokers showed a higher risk of postoperative fractures than both former smokers (HR, 3.63) and nonsmokers (HR, 6.99). This study demonstrates that smoking is a significant risk factor of complications after TSA and RSA. These findings emphasize the need for preoperative collaborative interventions, including smoking cessation programs.

Indications for prophylactic osteosynthesis associated with curettage in benign and low-grade malignant primitive bone tumors of the distal femur in adult patients: a case series.

BackgroundThe aim of the study was to evaluate whether the use of preventive osteosynthesis after curettage in benign and primitive low-grade malignant bone tumor localized in the distal femur in adult patients provides sufficient mechanical stability to the system as to allow weight-bearing and reduce the risk of postoperative fracture. Additionally, lower limb function after curettage and preventive osteosynthesis was evaluated.Materials and methodsWe analyzed twelve cases of benign and low-grade malignant bone lesions of the distal femur in adult patients treated in our orthopedic department between 2008 and 2011 with curettage, bone filling and preventive osteosynthesis. All patients were treated with curettage with the use of high-speed cutters, plus liquid nitrogen as local adjuvant in low-grade malignant lesions, and filling of the lesion with bone graft or allograft or acrylic cement, followed by osteosynthesis.ResultsNo fractures or major complications were observed; good function of the knee was observed.ConclusionWe recommend preventive osteosynthesis after curettage in patients with very large lesions (>5 cm, >60 cm3) or high functional requirements, in obese patients, and when local adjuvants are used.Level of evidenceLevel IV retrospective case-series study.

Epidemiology of periprosthetic femoral fractures in 5417 revision total hip arthroplasties: a 40-year experience.

The goals of this study were to define the risk factors, characteristics, and chronology of fractures in 5417 revision total hip arthroplasties (THAs). From our hospital's prospectively collected database we identified all patients who had undergone a revision THA between 1969 and 2011 which involved the femoral stem. The patients' medical records and radiographs were examined and the relevant data extracted. Post-operative periprosthetic fractures were classified using the Vancouver system. A total of 5417 revision THAs were identified. There were 668 intra-operative fractures, giving an incidence of 12%. Fractures were three times more common with uncemented stems (19%) than with cemented stems (6%) (p < 0.001). The incidence of intra-operative femoral fracture varied by uncemented stem type: fully-coated (20%); proximally-coated (19%); modular fluted tapered (16%) (p < 0.05). Most fractures occurred during the insertion of the femoral component (35%). One-third involved the diaphysis and 26% were of the calcar: 69% were undisplaced. There were 281 post-operative fractures of the femur (20-year probability = 11%). There was no difference in risk for cemented and uncemented stems. Post-operative fractures were more common in men < 70 years (p = 0.02). Periprosthetic fractures occurred earlier after uncemented revision of the femoral component, but later after a cemented revision. The most common fracture type was a Vancouver B1 (31%). Of all post-operative fractures, 24% underwent open reduction and internal fixation and 15% revision arthroplasty. In revision THA, intra-operative fractures occurred three times more often with an uncemented stem. Many were undisplaced diaphyseal fractures treated with cerclage fixation. While the risk of post-operative fracture is similar between uncemented and cemented components, they occur at notably different times depending on the type of stem fixation. In revision THA, intra-operative periprosthetic femoral fractures occur three times more often with uncemented stems. Many are non-displaced diaphyseal fractures treated with cerclage fixation. While postoperative fracture risks are equivalent between uncemented and cemented components, they occur at notably different time periods based on stem fixation type.

Epidemiology of periprosthetic fracture of the femur in 32644 primary total hip arthroplasties: a 40-year experience.

The goals of this study were to define the risk factors, nature, chronology, and treatment strategies adopted for periprosthetic femoral fractures in 32 644 primary total hip arthroplasties (THAs). There were 564 intra-operative fractures (1.7%); 529 during uncemented stem placement (3.0%) and 35 during cemented stem placement (0.23%). Intra-operative fractures were more common in females and patients over 65 years (p < 0.001). The majority occurred during placement of the femoral component (60%), and involved the calcar (69%). There were 557 post-operative fractures (20-year probability: 3.5%; 95% confidence interval (CI) 3.2 to 3.9); 335 fractures after placement of an uncemented stem (20-year probability: 7.7%; 95% CI 6.2 to 9.1) and 222 after placement of a cemented stem (20-year probability: 2.1%; 95% CI 1.8 to 2.5). The probability of a post-operative fracture within 30 days after an uncemented stem was ten times higher than a cemented stem. The most common post-operative fracture type was a Vancouver AG (32%; n = 135), with 67% occurring after a fall. In all, 36% (n = 152) were treated with revision arthroplasty. In summary, intra-operative fractures occur 14 times more often with uncemented stems. Female patients over 65 years of age are at highest risk. Post-operative fractures are also most common with uncemented stems, but are independent of age or gender. Cumulative risk of post-operative periprosthetic femur fracture was 3.5% at 20 years. Intra-operative fractures occur 14 times more often with uncemented stems, particularly with female patients over 65 years of age, while post-operative fracture risk is independent of age or gender, but still increased with uncemented stems.

Risk Factors for Perioperative Femoral Fractures: Cementless Femoral Implants and the Direct Anterior Approach Using a Fracture Table

BackgroundWith the increased popularity of the direct anterior approach, the issue of periprosthetic femur fractures has come into focus. The purpose of this article is to identify patient- and procedure-related characteristics that are associated with periprosthetic femur fractures in cementless total hip arthroplasties performed through a direct anterior approach using a fracture table. MethodsFive hundred primary total hip arthroplasties performed using cementless femoral implants through a direct anterior approach using a fracture table were evaluated for characteristics associated with perioperative prosthetic femur fracture within the first 3 months of surgery. ResultsTwenty-three hips (4.6%) incurred fractures, 13 (2.6%) intraoperative and 10 (2.0%) postoperative. Bivariate analyses demonstrated females and a body mass index (BMI) >40 with a higher risk of fractures overall and postoperative fractures. A significant difference in DORR ratios was seen in patients with intraoperative fractures and a significant difference seen with implant sizes in patients with postoperative fractures. Multivariable regression analyses demonstrated an increased risk of postoperative fracture with a BMI >40. As the DORR ratio and implant size increased, there was a reduced odds of intraoperative fracture. ConclusionConcern for periprosthetic femur fractures using the direct anterior approach for total hip arthroplasty is high in female patients and in patients with morbid obesity (BMI >40), small DORR ratio, or small implant size.

Failure Analysis Following Osteochondroplasty for Hip Impingement in Osteoporotic and Non-Osteoporotic Bones

Femoral osteochondroplasty is the most common treatment for femoroacetabular impingement (FAI). The risk of femoral neck fracture is increased following surgery and increases further when the bone is osteoporotic. The current requirement to undertake osteochondroplasty on patients with osteoporosis is forecast to increase; however, the effect of osteoporosis on the risk of post operative fracture is currently unknown. We developed three three-dimensional (3D) finite element models using computerised tomography (CT) scan data for a hip with cam-type impingement and used them to investigate the association between osteoporosis and the increased possibility of femoral neck fracture after femoral osteochondroplasty. Femoral osteochondroplasty was performed “virtually” on the intact hip model to two different resection depths, a ‘standard’ (6 mm) and a ‘critical’ resection (12 mm) depth, corresponding to 18% and 36% of the overall femoral neck diameter, respectively. Cortical and trabecular bone were included in the intact and resection hip models, and material properties representing both non-osteoporotic and osteoporotic cases employed, overall, 18 scenarios were analysed. Loading corresponding to “descending stairs” and “stumbling” activities were applied in the models enabling fracture propensity to be estimated. Our model predicted that fracture propagation can occur in the bone of osteoporotic patients following osteochondroplasty during typical daily activities, such as descending stairs. The level of damage increases significantly when patients are subjected to high load conditions and activities, even in non-osteoporotic patients, indicating an increased likelihood of fracture occurring. In the “stumbling activity” simulation, osteoporotic trabecular bone damage volume approached 50% for the 6 mm resection, rising to 70% at a resection depth of 12 mm. The corresponding rise in osteoporotic cortical bone volume damage was from 6% to 10%. Our findings support the recommendation for protected weight-bearing in patients in the postoperative phase and suggest an extended period of protected weight-bearing in osteoporotic patients could be considered.

Cementless or Cemented Fixation in Proximal Interphalangeal Joint Surface Replacement Arthroplasty?: Level 2 Evidence

Hypothesis: There is a paucity of literature evaluating periprosthetic fractures in total wrist arthroplasty. The purpose of this study was to assess the factors that contributed to an increased risk for fracture and the long-term outcomes after fracture stabilization. Methods: At a single institution over a 40-year period from 1974-2013, 425 total wrist arthroplasties were performed, with a minimum of 2-year followup for inclusion into this study. Demographics included age (57 years), BMI (27), and female (72%). The mean OR time was 185 minutes, while the mean tourniquet time was 135 minutes. The primary diagnosis for the TWA included 22 (5%) osteoarthritis (OA), 375 (88%) inflammatory arthritis, and 28 (7%) post-traumatic arthritis. The implants breakdown was: Remotions (n1⁄431), Biax (n1⁄4159), Volz (n1⁄433), Meuli (n1⁄4138), Universal (n1⁄47), and Swanson (n1⁄457). 357 (84%) were cemented, while 36 (8%) required bone graft. Results: Intraoperative periprosthetic fractures occurred in 9 (2%) wrists. The distal metacarpals where fractured in 5, while the distal radius was fractured in 4. Univariate regression analysis demonstrated that increasing age (P 1⁄4 0.007), Biax implants (P 1⁄4 0.07), and osteoarthritis (P 1⁄4 0.07) in increased fracture risk, as summarized in Table 1. At a mean follow-up of 12 years (2-22), 1 (8%) patient who had an intraoperative fracture suffered a postoperative fracture, compared to 12 (3%) patients without intraoperative fractures (P 1⁄4 0.27). (P 1⁄4 0.27). One patient who had an intraoperative fracture underwent revision surgery for pain and limited motion. No other patients suffered any complications. The 5 and 10 year survival after intraoperative fracture was 88%, 88%, compared to 84% and 74% without a fracture (P 1⁄4 0.39). There were 13 patients who suffered postoperative fractures overall. The 5, 10, and 20 year survival free of postoperative fracture was 99%, 96%, and 94%, respectively. The implant breakdown for these fractures was Swanson (n1⁄45), Volz (n1⁄40), Meuli (n1⁄44), Biax (n1⁄43), Remotion (n1⁄41), Universal (n1⁄40). The risk of postoperative fracture was increased by increasing age (P 1⁄4 0.07), while patients with Swanson (P 1⁄4 0.02) and Volz (P 1⁄4 0.14) implants had lower rates of fracture. Summary Points: Intraoperative fractures occur in approximately 2% of total wrist arthroplasties. When properly stabilized, these do not affect long-term outcomes. The implant design is an important factor in the risk of intraoperative and postoperative fractures.