Periprosthetic fracture following arthroplasty for femoral neck fracture: is a cemented stem protective?

BACKGROUND: Periprosthetic femoral fractures (PFF) carry significant morbidity following arthroplasty for femoral neck fracture (FNF). This study assessed fracture complications following arthroplasty for FNF and the effect of cement fixation of the femoral component on intraoperative and post-operative PFF. METHODS: Between February 2014 and September 2021, 740 patients with a FNF who underwent arthroplasty were analyzed for demographics, surgical management, use of cement for fixation of the femoral component, and subsequent PFF. Variables were compared with Mann-Whitney or Chi-square as appropriate. Multivariate logistic regression was used to assess independent risk factors associated with intraoperative or post-operative PFF. RESULTS: There were 163 THAs (41% cemented) and 577 HAs (95% cemented). There were 28 PFFs (3.8%): 18 post-operative and 10 intraoperative. Fewer post-operative PFFs occurred with cemented stems (1.63% vs. 6.30%, p = 0.002). Mean time from surgery to presentation with post-operative PFF was 14 months (0-45 months). Mean follow-up time was 10.3 months (range: 0-75.7 months). In multivariate regression, use of cement and THA was independently associated with decreased post-operative PFF (cement: OR 0.112, 95% CI 0.036-0.352, p < 0.001 and THA: OR 0.249, 95% CI 0.064-0.961, p = 0.044). More intraoperative fractures occurred during THA (3.68% vs. 0.69%, p = 0.004) and non-cemented procedures (5.51% vs. 0.49%, p < 0.001). In multivariate regression, use of cement was protective against intraoperative fracture (OR 0.100, CI 0.017-0.571, p = 0.010). CONCLUSIONS: In patients with a FNF treated with arthroplasty, cementing the femoral component is associated with a lower risk of intraoperative and post-operative PFF. Choice of procedure may be based on patient factors and surgeon preference.

Changing practice to a new-generation triple-taper collared femoral component reduces periprosthetic fracture rates after primary total hip arthroplasty.

Aims: Periprosthetic femoral fracture (PPF) is a major complication following total hip arthroplasty (THA). Uncemented femoral components are widely preferred in primary THA, but are associated with higher PPF risk than cemented components. Collared components have reduced PPF rates following uncemented primary THA compared to collarless components, while maintaining similar prosthetic designs. The purpose of this study was to analyze PPF rate between collarless and collared component designs in a consecutive cohort of posterior approach THAs performed by two high-volume surgeons. Methods: This retrospective series included 1,888 uncemented primary THAs using the posterior approach performed by two surgeons (PKS, JMV) from January 2016 to December 2022. Both surgeons switched from collarless to collared components in mid-2020, which was the only change in surgical practice. Data related to component design, PPF rate, and requirement for revision surgery were collected. A total of 1,123 patients (59.5%) received a collarless femoral component and 765 (40.5%) received a collared component. PPFs were identified using medical records and radiological imaging. Fracture rates between collared and collarless components were analyzed. Power analysis confirmed 80% power of the sample to detect a significant difference in PPF rates, and a Fisher's exact test was performed to determine an association between collared and collarless component use on PPF rates. Results: Overall, 17 PPFs occurred (0.9%). There were 16 fractures out of 1,123 collarless femoral components (1.42%) and one fracture out of 765 collared components (0.13%; p = 0.002). The majority of fractures (n = 14; 82.4%) occurred within 90 days of primary THA. There were ten reoperations for PPF with collarless components (0.89%) and one reoperation with a collared component (0.13%; p = 0.034). Conclusion: Collared femoral components were associated with significant decreases in PPF rate and reoperation rate for PPF compared to collarless components in uncemented primary THA. Future studies should investigate whether new-generation collared components reduce PPF rates with longer-term follow-up.

Sex-Specific Implant Fixation Can Reduce Revision Rates in Total Hip Arthroplasty: Evidence From the Swiss National Joint Registry.

BACKGROUND: Patient's sex is considered a risk factor for revision following primary total hip arthroplasty (THA), but sex-specific treatment guidelines are lacking. The purpose was to assess sex-specificity of risk factors for periprosthetic femoral fractures (PFFs) and aseptic stem loosening (ASL) in a nationwide register study. METHODS: All uncemented and hybrid THAs for hip osteoarthritis registered in the Swiss National Joint Registry were considered. 86,423 THAs were analyzed. Comparable THA subsets for both sexes were obtained through propensity score matching (1:1). A sex-specific analysis of risk factors for early PFF or ASL was performed using recursive partitioning analyses. RESULTS: In women, PFFs were most significantly associated with uncemented THA fixation (P < .0001) and age (P < .01, threshold: 70.5 years). The ASLs were solely associated with patient age of <65 years (P = .023). In men, PFFs were associated exclusively with an American Society of Anesthesiologists (ASA) score >2 (P = .026). The ASLs were not correlated to any of the potential risk factors analyzed. A mathematical simulation indicated that avoiding uncemented THA fixation in women ≥70.5 years of age decreased the number of revisions within the observational period by 21% in this subset and by 4.9% in the entire patient population. CONCLUSION: Uncemented THA should be avoided in women >70.5 years due to the increased risk of early PFF, while the mode of stem fixation did not influence revision risk in men. A sex-specific regimen for THA fixation has the potential to markedly reduce early THA revision rates.

How Much Protection Does a Collar Provide? Assessing Risk of Early Periprosthetic Femur Fractures Following Total Hip Arthroplasty in Elderly Patients.

BACKGROUND: Periprosthetic fractures (PPFs) account for approximately 25% of early revisions following total hip arthroplasty (THA). Cemented femoral fixation is associated with a lower-risk of PPF, and collared-cementless stems may reduce the risk as well. The objective of this study was to compare early-PPF rates between cemented, collared-cementless, and non-collared cementless stems in elderly patients. METHODS: A consecutieve-series of 11,522 primary THAs performed between 2016 and 2021 at our institution in patients >65 years of age was identified. Stem types used were categorized as cemented, collared-cementless, or non-collared cementless. Patients undergoing THA who had cemented-stems were older, more commonly women, and more likely to have a posterior-approach. To reduce confounding of patient characteristics, we matched patients in the 3 stem-categories according to age, sex, and body mass index. This generated 3-groups (cemented, collared-cementless, and non-collared cementless) consisting of 936 patients per group. The mean age of these 2,808 patients was 73 years, the mean body mass index was 27, and 67% were women. Logistic regressions were used to evaluate risk-factors for early-PPF. In the entire cohort of primary THA in elderly patients, there were 85 early PPFs (0.7%) over the study period. RESULTS: Non-collared cementless stems were associated with an increased risk of early PPF (OR: 3.11; P = .03) compared to collared-cementless stems. There were no early PPFs in the matched cemented cohort, 6 early PPFs in the matched collared-cementless cohort, and 16 early-PPFs in the matched non-collared cementless cohort (0% versus 0.64% versus 1.71%, P < .001). CONCLUSIONS: In this large-series of patients >65 years of age undergoing primary THA, cemented stem fixation had the lowest incidence of early PPF, but collared-cementless stems had a nearly 3-fold decrease in risk for early PPF compared to non-collared cementless stems.

Reducing the Burden of Disease Associated With Periprosthetic Fractures: Prevention and the Need for Improved Perioperative Care.

The management of periprosthetic fractures remains challenging and controversial. There continues to be a significant burden of disease and substantial resource implications associated with fractures following total joint arthroplasty. Achieving consensus opinions regarding the prevention and treatment of this problem has important implications given the profound effect on patient outcomes. Multidisciplinary care in the preoperative and postoperative settings is critical, with a specific focus on bone health.

Cemented Femoral Fixation in Total Hip Arthroplasty Reduces the Risk of Periprosthetic Femur Fracture in Patients 65 Years and Older: An Analysis From the American Joint Replacement Registry.

BACKGROUND: Periprosthetic femur fracture (PPFx) is a devastating complication after total hip arthroplasty (THA). Despite concerns for increased PPFx, cementless fixation predominates in the United States. This study used the American Joint Replacement Registry to compare PPFx risk between cemented and cementless femoral fixation for THA. METHODS: An analysis of primary THA cases in patients aged 65 years and more was performed with the American Joint Replacement Registry data linked to Centers for Medicare and Medicaid Services data from 2012 to 2020. Analyses compared cemented to cementless femoral fixation. We identified 279,052 primary THAs, 266,040 (95.3%) with cementless and 13,012 (4.7%) with cemented femoral fixation. Cox proportional hazard regression analyses evaluated the association of fixation and PPFx risk, while adjusting for sex, age, and competing risk of mortality. Cumulative incidence function survival curves evaluated time to PPFx. RESULTS: Age ≥ 80 years (P < .0001) and women (P < .0001) were associated with PPFx. Compared to cemented stems, cementless stems had an elevated risk of PPFx (Hazards Ratio 7.70, 95% Confidence interval 3.2-18.6, P < .0001). The cumulative incidence function curves demonstrated an increased risk for PPFx across all time points for cementless stems, with equal magnitude of risk to 8 years.` CONCLUSION: Cementless femoral fixation in THA continues to predominate in the United States, with cementless femoral fixation demonstrating increased risk of PPFx in patients aged 65 years or more. Surgeons should consider greater use of cemented femoral fixation in this population to decrease the risk of PPFx.

Preoperative Statin Exposure Reduces Periprosthetic Fractures and Revisions following Total Knee Arthroplasty.

The purpose of this study is to examine patients undergoing primary total knee arthroplasty (TKA) with and without prior history of statin use. We specifically evaluated (1) 90-day to 2-year periprosthetic fractures, (2) revisions, and (3) respective risk factors. We queried a national, all-payer database for patients undergoing primary TKA between 2010 and 2020. Chronic statin exposure was then identified and defined as more than three prescriptions filled within 1 year prior to TKA (statin users). A control cohort of patients undergoing TKA without the prior history of statin use was then created (statin naïve). Cohorts were matched 1:1 based on age range, Charlson Comorbidity Index, sex, diabetes, obesity, and tobacco use, yielding 579,136 patients. Multivariate logistic regression was performed to evaluate the risk factors for periprosthetic fractures and revisions, adjusted for demographics and comorbidities. Statin users had a lower incidence of periprosthetic fractures from 90 days to 2 years compared with the statin naïve (p < 0.001). Similarly, statin users had a lower incidence of revisions at 90 days to 2 years (p < 0.001). Using the statin-naïve cohort as a reference, statin use was independently associated with decreased odds of periprosthetic fractures and revisions. Statin use was associated with a reduced risk of periprosthetic fractures and revisions. These results may mitigate postoperative risks though statin therapy is currently not recommended for fracture-related benefits alone.

Medium Activity Prevents Periprosthetic Bone Mass Loss in the Medial Metaphyseal Region of the Tibia after Posterior-Stabilized TKA: A 5-Year Follow-up Study of 110 Knees.

OBJECTIVE: The bone mass around the prosthesis plays an important role in the stability of the prosthesis. This study aimed to assess the effect of postoperative activity on bone mineral density (BMD) in the proximal tibia 5 years after total knee arthroplasty (TKA). To provide a scientific guidance for postoperative functional exercise. METHODS: 110 patients underwent unilateral primary TKA were divided into three groups based on the University of California Los Angeles (UCLA) activity scale: low activity group (LA group, UCLA = 4, 5); medium activity group (MA group, UCLA = 6, 7); and high activity group (HA group, UCLA = 8, 9). The primary observation was a comparison of the BMD and BMD change percentage (ΔBMD (%)) in the periprosthetic tibia among the LA, MA and HA groups at 1 year, 3 years and 5 years. The secondary observations were radiographic evaluation (prosthetic stability, periprosthetic fractures, aseptic loosening and periprosthetic joint infection) and clinical evaluation (Knee Society Score (KSS), visual analogue score scores and range of motion (ROM)). A one-way ANOVA was used to compare the clinical scores and BMD among the three groups. RESULTS: The BMD of medial region decreased by 10.80%, 12.64%, 13.61% at 1, 3, and 5 years respectively; these were 5.72%, 6.26%, 7.83% in lateral region and 1.42%, 1.78%, 3.28% in diaphyseal region. For medial metaphyseal region, the BMD of the MA group was significantly greater than that of the LA and HA groups at 1 and 3 years (108.9 ± 5.2 vs. 106.1 ± 6.69 vs. 105.4 ± 5.2 and 108.5 ± 6.0 vs. 101.2 ± 6.76 vs. 103.0 ± 6.8, P < 0.01 and P < 0.001), and the BMD changes (ΔBMD (%)) in the MA group were significantly smaller than those in the LA and HA groups (8.75 ± 5.36 vs. 11.92 ± 5.49 vs. 12.70 ± 5.21 and 9.11 ± 5.11 vs. 16.04 ± 4.79 vs. 14.82 ± 4.26, P < 0.01 and P < 0.001). Regarding secondary observations, all of the prostheses were assessed as stable, without periprosthetic fractures, aseptic loosening and periprosthetic joint infection. Regarding KSS scores, there was no significant difference among the three groups. However, the VAS and ROM of the HA group were better than those of the MA and LA groups (1.65 ± 0.79 vs. 2.63 ± 0.77 vs. 3.00 ± 1.17, p < 0.001, and 111.90 ± 9.17 vs. 110.20 ± 6.78 vs. 102.90 ± 8.48, P < 0.001). CONCLUSION: Medium activity prevented periprosthetic bone loss in the medial metaphyseal region of the tibia after posterior-stabilized TKA, and moderate-intensity exercise is recommended for patients after TKA to reduce periprosthetic bone loss.

Effectiveness of prophylactic double-looped wiring in cementless Hip arthroplasty: A biomechanical study in osteoporotic bone model using impaction simulation system.

BACKGROUND: Periprosthetic femoral fracture (PFF) is well-known complication in cementless hip arthroplasty (HA), especially in the elderly with osteoporosis. To prevent intraoperative PFFs during HA, prophylactic cerclage wiring on the calcar area during femoral broaching and implant insertion is recommended. However, biomechanical data on the benefits of cerclage wiring in osteoporotic bone during impaction are limited and controversial. This study aimed to assess the efficacy of prophylactic double-looped cerclage wiring (PDLCW) during femoral broaching in the osteoporotic bone model with an impaction simulation system. METHODS: Fifteen osteoporotic femur models were prepared and allocated to three groups; control group (no cerclage), PW group (received PDLCW), and CC+PW group (prepared as having calcar crack and received PDLCW). All femurs were broached under impaction force that sequentially increased until the visible fracture or calcar crack propagation was visible. The primary outcomes were mallet impaction force (MIF-CF) and mallet velocity (MV-CF) at the time of calcar fracture. The secondary outcomes were calcar fracture pattern and subsidence during calcar fracture (S-CF). RESULTS: PW group showed a significant increase in average MIF-CF, by 40.4% and 120.2% (p<0.001) compared to the control and CC+PW groups, respectively. The average MV-CF in PW group was also significantly greater, 13.1% and 64.6% (p<0.001), compared to the control and CC+PW groups, respectively. Control group revealed significantly greater incidence of complete calcar fracture (60% vs. 0% vs. 0%, p = 0.024), and the highest S-CF compared to those in the PW and CC+PW groups (10.6 ±â€¯6.0 mm, 6.7 ±â€¯4.4 mm, and 1.3 ±â€¯2.0 mm, p = 0.020). CONCLUSIONS: This study showed that PDLCW significantly improved hoop stress resistance by increasing the calcar fracture threshold related to mallet impaction, decreasing the risk of complete calcar fracture.

Prophylactic Cerclage Cabling Decreases the Intraoperative Periprosthetic Fracture Rate during Cement-Less Total Hip Arthroplasty in Patients with Severe Developmental Hip Dysplasia.

PURPOSE OF THE STUDY Cementless stems in highly dysplastic hips are considered to increase the risk of femoral fracture and associated morbidity. Several authors speculated to use prophylactic cabling in this patient group to prevent intraoperative fractures. This study aims to reveal objective results regarding the perioperative complications in a large and consecutive patient group with respect to use of prophylactic cabling. MATERIAL AND METHODS A retrospective comparative study was planned. A total of 122 consecutive patients with dysplastic hips of Crowe type 3 or 4, operated on with total hip arthroplasty (THA) and shortening osteotomy using a rectangular femoral stem were included. Patients were stratified according to use of a diaphyseal prophylactic cerclage cable. Perioperative complications were recorded. Clinical outcome was measured in terms of Harris Hip Score and Visual Analog Scale (VAS) for pain. All results were compared between the groups. RESULTS The mean follow-up time was 27 months. Two (2%) versus five (14%) patients had a fracture at the diaphyseal level in cabled versus non-cabled groups. Difference between groups was statistically significant (p=0.01). Relative risk of fracture in case of a non-cabling was 5.8 (p=0.03). Eleven (9%) patients had a non-displaced fracture at the metaphyseal level. No significant differences were detected with respect to preoperative clinical outcome scores or change in these scores between groups. CONCLUSIONS Femoral diaphyseal fracture rates are low when cementless, rectangular stems are used in dysplastic high riding hips. Prophylactic cerclage cabling further decreases the fracture risk and eases treatment in case of a fracture without causing additional complications and therefore is recommended. Key words: intraoperative fracture, periprosthetic fracture, total hip arthroplasty, cerclage cabling, developmental hip dysplasia, transverse shortening osteotomy.

Tibial cutting guide (resector) holding pins position and subsequent risks of periprosthetic fracture in unicompartmental knee arthroplasty: a finite element analysis study.

BACKGROUND: Periprosthetic fracture of the tibia after unicompartmental knee arthroplasty has been reported to be associated with excessive pin holes created for stabilization of the cutting guide. However, fractures have also been reported in cases using two pins as in the method suggested by the manufacturer. It is currently unclear whether variations in pinhole positions make a difference in proximal tibial fracture risk. METHODS: Finite element models were constructed using Chinese female bone computed tomography images, with bone cuts made according to the surgical steps of implanting a fixed bearing unicompartmental arthroplasty. Four combinations of pinholes (pins placed more closely to the medial tibial cortex or centrally along the mechanical axis as allowed by the tibial cutting guide) created for tibial cutting guide placement were tested by finite element analyses. Testing loads were applied for simulating standing postures. The maximum von Mises stress on the tibial plateau was evaluated. RESULTS: Pinhole placed close to the medial edge of the proximal tibial plateau is associated with the highest stress (27.67 Mpa) and is more likely to result in medial tibial fracture. On the contrary, pinhole placed along the central axis near the tibial tuberosity has the lowest stress (1.71 Mpa) and reflects lower risk of fracture. CONCLUSION: The present study revealed that placing tibial cutting guide holding pins centrally would lower the risks of periprosthetic fracture of the medial tibial plateau by analyzing the associated stress in various pin hole positions using finite element analysis.

Introduction of a New Treatment Algorithm Reduces the Number of Periprosthetic Femoral Fractures After Primary Total Hip Arthroplasty in Elderly Females.

BACKGROUND: Increasing global usage of cementless prostheses in total hip arthroplasty (THA) presents a challenge, especially for elderly patients. To reduce the risk of early periprosthetic femoral fractures (PFFs), a new treatment algorithm for females older than 60 years undergoing primary THA was introduced. The aim of this study was to determine the impact of the new treatment algorithm on the early risk of perioperative and postoperative PFFs and guideline compliance. METHODS: A total of 2405 consecutive THAs that underwent primary unilateral THA at our institution were retrospectively identified in the period January 1, 2013-December 31, 2018. A new treatment algorithm was introduced on April 1, 2017 with female patients aged older than 60 years intended to receive cemented femoral components. Before this, all patients were scheduled to receive cementless femoral components. Demographic data, number of perioperative and postoperative PFFs, and surgical compliance were recorded, analyzed, and intergroup differences compared. RESULTS: The utilization of cemented components in female patients older than 60 years increased from 12.3% (n = 102) to 82.5% (n = 264). In females older than 60 years, a significant reduction in the risk in early postoperative and intraoperative PFF after introduction of the new treatment algorithm was seen (4.57% vs 1.25%; P = .007 and 2.29% vs 0.31%; P = .02, respectively). Overall risk for postoperative and intraoperative fractures combined was also reduced in the entire cohort (4.1% vs 2.0%; P = .01). CONCLUSION: Use of cemented fixation of the femoral component in female patients older than 60 years significantly reduces the number of PFFs. Our findings support use of cemented femoral fixation in elderly female patients.

A Calcar Collar Is Protective Against Early Torsional/Spiral Periprosthetic Femoral Fracture: A Paired Cadaveric Biomechanical Analysis.

BACKGROUND: Periprosthetic fracture is a leading reason for readmission following total hip arthroplasty. Most of these fractures occur during the early postoperative period before bone ingrowth. Before ingrowth occurs, the femoral component can rotate relative to the femoral canal, causing a spiral fracture pattern. We sought to evaluate, in a paired cadaver model, whether the torsional load to fracture was higher in collared stems. The hypothesis was that collared stems have greater load to fracture under axial and torsional loads compared with collarless stems. METHODS: Twenty-two cadaveric femora (11 matched pairs) with a mean age of 77 ± 10.2 years (range, 54 to 90 years) were harvested. Following dissection, the femora were evaluated with use of a dual x-ray absorptiometry scanner and T scores were recorded. We utilized a common stem that is available with the same intraosseous geometry with and without a collar. For each pair, 1 femur was implanted with a collared stem and the contralateral femur was implanted with a collarless stem with use of a standard broaching technique. A compressive 68-kg load was applied to simulate body weight during ambulation. A rotational displacement was then applied until fracture occurred. Peak torque prior to fracture was measured with use of a torque meter load cell and data acquisition software. RESULTS: The median torque to fracture was 65.4 Nm for collared stems and 43.1 Nm for uncollared stems (p = 0.0014, Wilcoxon signed-rank test). The median T score was -1.95 (range, -4.1 to -0.15). The median difference in torque to fracture was 29.18 Nm. As expected in each case, the mode of failure was a spiral fracture around the implant. CONCLUSIONS: Collared stems seemed to offer a protective effect in torsional loading in this biomechanical model comparing matched femora. CLINICAL RELEVANCE: These results may translate into a protective effect against early periprosthetic Vancouver B2 femoral fractures that occur before osseous integration has occurred.

The Use of Cement in Hip Arthroplasty: A Contemporary Perspective.

Notable advances in hip arthroplasty implants and techniques over the past 60 years have yielded excellent survivorship of fully cemented, hybrid, and reverse hybrid total hip replacements as demonstrated in joint registries worldwide. Major advances in noncemented implants have reduced the use of cement, particularly in North America. Noncemented implants predominate today based on procedural efficiency, concern related to thromboembolic risk, and a historic belief that cement was the primary cause of osteolysis and implant loosening. With the decline of cemented techniques, press-fit fixation has become common even in osteoporotic elderly patients. Unfortunately, there is a troubling rise in intraoperative, as well as early and late postoperative periprosthetic fractures associated with the use of noncemented implants. Despite the success of noncemented fixation, an understanding of modern cement techniques and cemented implant designs is useful to mitigate the risk of periprosthetic fractures. Cemented acetabular components can be considered in elderly patients with osteoporotic or pathologic bone. Cemented stems should be considered with abnormal proximal femoral morphology, conversion of failed hip fixation, inflammatory arthritis, patient age over 75 (especially women), osteoporotic bone (Dorr C), and in the treatment of femoral neck fractures.

Inter-implant fractures: an unmet medical need-a preventive approach proposal.

Inter-implant fractures are associated with reduced quality of life and increased 1-year mortality. For that reason, we propose, instead of treating, a novel, preventative surgical approach that involves splinting the inter-implant femoral shaft interval. In patients with a previous femoral implant in whom a second surgery for new material implantation was necessary (including knee or hip arthroplasty, plate or femoral nailing), an overlapping technique using the minimally invasive plate osteosynthesis technique was performed during the second surgery. Nine patients were included, all females with median (range) age of 78 (55-88) years. No surgery-related complications or mortality occurred. Two patients suffered fractures from a casual fall postoperatively with no implant failure or hospital admission required. In conclusion, instead of treating such fractures after they occur, we propose an effective, safe and reproducible preventative surgical approach, not previously reported, which involves internal femoral splinting, a plate and the minimally invasive plate osteosynthesis technique.

A calcar collar is protective against early periprosthetic femoral fracture around cementless femoral components in primary total hip arthroplasty: a registry study with biomechanical validation.

AIMS: The aim of this study was to estimate the 90-day risk of revision for periprosthetic femoral fracture associated with design features of cementless femoral stems, and to investigate the effect of a collar on this risk using a biomechanical in vitro model. MATERIALS AND METHODS: A total of 337 647 primary total hip arthroplasties (THAs) from the United Kingdom National Joint Registry (NJR) were included in a multivariable survival and regression analysis to identify the adjusted hazard of revision for periprosthetic fracture following primary THA using a cementless stem. The effect of a collar in cementless THA on this risk was evaluated in an in vitro model using paired fresh frozen cadaveric femora. RESULTS: The prevalence of early revision for periprosthetic fracture was 0.34% (1180/337 647) and 44.0% (520/1180) occurred within 90 days of surgery. Implant risk factors included: collarless stem, non-grit-blasted finish, and triple-tapered design. In the in vitro model, a medial calcar collar consistently improved the stability and resistance to fracture. CONCLUSION: Analysis of features of stem design in registry data is a useful method of identifying implant characteristics that affect the risk of early periprosthetic fracture around a cementless femoral stem. A collar on the calcar reduced the risk of an early periprosthetic fracture and this was confirmed by biomechanical testing. This approach may be useful in the analysis of other uncommon modes of failure after THA. Cite this article: Bone Joint J 2019;101-B:779-786.

Can Prophylactic Cables Stop Crack Propagation in Revision Arthroplasty: A Biomechanical Study.

BACKGROUND: Intraoperative femur fractures are a common complication of revision hip arthroplasty. This study examined the use of a prophylactic cable in stopping a crack from propagating beyond the cable. METHODS: Seventy sheep femora were prepared. A 5-mm vertical incision was performed. Using a force-controlled materials testing machine, a Wagner shaft was advanced until a crack occurred. Cracks were visualized with green ink. In the first part, the control group without any cable (n = 10) was compared with polyethylene (n = 15) and single CoCr cable (n = 15) groups. The cables were positioned 15 mm distal to the osteotomy. In the second part, three different CoCr configurations were compared, single-wrapped (n = 15), double-wrapped (n = 125), and two separate cables at 10 and 15 mm distal to the osteotomy (n = 15). RESULTS: The polyethylene cable stopped only 3 of 15 cracks (20%), whereas the CoCr cable stopped 11 of 15 cracks (73%) (P = .009). The force needed to initiate the crack between the different groups was not significant. Twelve (80%) of 15 cracks were stopped at the level of the cable with two separate CoCr cables and 15 (100%) of 15 cracks with a double-wrapped cable (P = .11). CONCLUSION: This study demonstrated that an elastic cable is not suitable for preventive cabling. The force required to form a crack is not improved with the use of a prophylactic cable placed 10-15 mm below the osteotomy. While the results on the different configurations were not conclusive, the double-wrapped cable was able to stop all cracks from progressing distally.

Distal Femur Locking Plates Fit Poorly Before and After Total Knee Arthroplasty.

OBJECTIVE: To evaluate the fit of distal femur locking plates. Secondarily, we sought to compare plate fit among patients with and without a total knee arthroplasty (TKA). DESIGN: Retrospective. SETTING: University hospital. INTERVENTION: Standard length precontoured distal femur locking plates from 4 manufacturers were digitally templated onto each patient's pre-TKA and post-TKA radiographs. MAIN OUTCOME MEASUREMENTS: The maximum distance from the plate to the lateral femoral cortex (plate-bone distance) was measured in the metaphyseal region. Mean plate-bone distances were compared between manufacturers and between pre-TKA and post-TKA radiographs. RESULTS: All implants tested were undercontoured in all patients. Plate-bone distances ranged from 6.6 ± 0.4 mm to 8.0 ± 0.4 mm (mean ± SE) pre-TKA and 8.2 ± 0.3 mm to 8.6 ± 0.3 mm after TKA, indicating worse fit after arthroplasty (P < 0.001). There were also intermanufacturer differences, with Synthes and Smith & Nephew implants demonstrating the lowest plate-bone distances in the pre-TKA and post-TKA groups, respectively. Proportionally, plate-bone increase was greater in the female cohort (16%) compared with the male cohort (8%). CONCLUSIONS: There was plate-bone mismatch for the distal femur locking plates tested in this study, due to undercontouring of the implants. After patients underwent TKA, poor implant fit was exacerbated. Surgeons must be aware of the potential for deformity if the proximal segment is brought into contact with the implant. These finding may help optimize implant design for the treatment of periprosthetic distal femur fractures.

Midterm results of the cylindrical fully porous-coated uncemented femoral stem in revision patients with Paprosky I-IIIA femoral defects.

INTRODUCTION: The aim of this study was to analyze the survival of the Echelon® femoral stems in revision hip surgeries in patients with Paprosky I-IIIA femoral defects. PATIENTS AND METHODS: Sixty-six patients (70 hips) who underwent revision hip surgery with at least 3 years of follow-up data were included in the study between 2000 and 2013. The mean patient age was 64.5 (32-83) years, and the mean follow-up period was 93 (45-206) months. The reasons for revision were aseptic loosening in 55 (78.6%) patients, periprosthetic joint infection in 9 (12.9%) patients, periprosthetic fracture in 4 (5.7%) patients, and stem fracture in 2 (2.9%) patients. The preoperative and postoperative follow-up X-rays and functional scores were evaluated. RESULTS: Five patients died in an average of 70 (45-86) months after surgery due to non-related diseases. We encountered sciatic nerve palsy in two patients and early hip dislocation in two patients, whereas 54 patients were able to walk without any assistive device. The remaining 12 patients required an assistive device to walk. The mean Harris hip score significantly increased from 34 (7-63) preoperatively to 72 (43-96) postoperatively. Aseptic loosening was observed in one patient. The survival of the porous-coated anatomical uncemented femoral stem was 98.4% over 10 years. CONCLUSION: This study showed that good clinical outcomes and survival can be obtained when using porous-coated anatomical uncemented femoral stems.

Restoration of proximal periprosthetic bone loss by denosumab in cementless total hip arthroplasty.

Denosumab contributed to the restoration of proximal periprosthetic bone loss around the femoral stem that were measured using a DEXA, especially in zone 7, at 1 year after cementless THA in elderly osteoporotic patients. INTRODUCTION: Although bone quality is an important issue in elderly osteoporotic patients who underwent total hip arthroplasty (THA) with a cementless stem, periprosthetic bone mineral density (BMD) in the proximal femur has been reported to be decreased by 15-40% postoperatively. Some authors have examined the use of several types of bisphosphonates to prevent decreases in BMD in the proximal femur after cementless THA; however, few reports have demonstrated success in restoring BMD in the proximal medial femoral bone, such as zone 7. METHODS: We conducted prospective study comparing patients who underwent cementless THA administered with denosumab (10 patients) and without denosumab (10 patients). BMD around the femoral stem were measured using a DEXA immediately after surgery, and at 6 months and at 1 year after surgery. No difference was found between the two groups referred to the patient's demographic data. RESULTS: We found that denosumab displayed definitive effects in increasing the % change in periprosthetic BMD at zone 7 by an average of 7.3% in patients with cementless THA, compared to control group who were given only vitamin D. CONCLUSION: Denosumab is one of a number of anti-osteoporotic agents to have a definitive effect on the restoration of proximal periprosthetic bone loss, especially in zone 7, after cementless THA. Denosumab contributed to the restoration of decreased periprosthetic BMD to normal levels. As the decrease in BMD in the proximal femur after THA is considered to be apparent at 6-12 months after surgery, it is believed that prevention of the deterioration of bone quality is important in the proximal femur immediately after cementless THA for elderly female patients with osteoporosis.