Higher rates of intraoperative fractures with compaction broaching compared to conventional broaching during hip hemiarthroplasty for femoral neck fractures.

PURPOSE: Intraoperative periprosthetic femoral fracture (IPFF) is a known iatrogenic complication during hemiarthroplasty (HA) which may lead to inferior outcomes. The risk factors for IPFF during HA in displaced femoral neck fractures (FNF) remains to be fully elucidated. This study aims to compare IPFF rates between compaction broaching and conventional broaching techniques for cementless HA in FNF. METHODS: We retrospectively reviewed institutional surgical data of patients who underwent cementless HA for displaced FNF from January 2010 to January 2022. Patients were stratified into two groups based on the broaching system: conventional broaching and compaction broaching. The presence, location, and treatment of IPFF were assessed for both groups. Effect of IPFF on postoperative weight-bearing status, mortality readmission and revision rates were compared between groups. RESULTS: A total of 1,586 patients included in the study. 1252 patients (78.9%) in the conventional broaching group and 334 patients (21.1%) in the compaction broaching group. A total of 104 IPFF were found (6.5%). As compared to conventional broaching, compaction broaching was associated with significant higher IPFF rates (12.9% vs. 4.9%, p < 0.001, OR 2.84, CI 1.88-4.30). The location of the IPFF was similar between groups (p = 0.366), as well as the intraoperative treatment (p = 0.103) and postoperative weight-bearing status (p = 0.640). Surgical time, mortality rates, readmission rates and revision rates were comparable between groups. In a multivariate regression analysis, compaction broaching (OR, 4.24; p < 0.001) was independently associated with IPFF. CONCLUSIONS: This study reveals higher rates of IPFF associated with compaction broaching. Although this finding may have minimal clinical relevance, surgeons should consider these results when considering implant selection.

Uncovering Patterns in Perceived Therapist Behaviour: A Latent Profile Analysis of Broaching Experiences Among Ethnic Minority Group Member Clients.

OBJECTIVE: Recent research shows that for clients who identify as ethnic minority group members, therapists' effort to include ethnic-cultural topics in therapy conversations-that is, broaching-is important for clients' evaluations of therapy and symptom improvement. However, little is known about how this is experienced by clients and how different patterns of broaching behaviours are related to the therapeutic process. This study aimed to identify meaningful combinations of therapist broaching behaviours in a sample of clients that identify as ethnic minority group members in outpatient psychotherapy (N = 452; 64.6% women, 33.6% men, 1.3% nonbinary; 0.4% preferred not to say; Mage = 33.8). METHODS: In the present research, we employed latent profile analysis to discern therapist profiles based on the similarity of their reported broaching behaviours. Group differences were analysed with Welch's analysis of variance. RESULTS: Five profiles were delineated, each revealing specific broaching patterns. The obtained profiles were named Pending, Neutral, Inappropriate, Uninvolved and Engaged. Reported cultural identity concealment was lower and client-estimated improvement higher in the Pending and Engaged profiles compared to the Inappropriate profile. Both the Neutral and Uninvolved profiles yielded scores in between. CONCLUSIONS: Pending and Engaged profiles are equally beneficial and the Inappropriate profile is the most harmful in terms of reported cultural concealment and client-estimated improvement. Implications of findings for practice, training and research are discussed.

The development of the Broaching Assessment Scale: A client-rated measure of therapists' broaching behaviour in clinical counselling.

Objective: Addressing ethnic-cultural topics during the process of psychotherapy, i.e. broaching, is considered highly important for ethnic minority clients who consult mental health care services. Surprisingly little is known, however, about clients' perception of a therapist's broaching qualities, and how clients' mental construction of broaching translates into behavioural broaching acts a therapist may display.Method: Based on previous work and nine in-depth interviews with ethnic minority clients, a client-rated measure of therapists' broaching behaviour was developed and psychometrically evaluated in two samples. Sample 1 (N = 252 UK ethnic minority clients) was used to empirically delineate the factor structure of an initial item set. Participants were then resolicited to complete a revised item pool.Results: The empirical structure resulted in a final 25-item broaching instrument with five subscales probing into therapists' broaching behaviour. This Broaching Assessment Scale (BrAS) was validated in Sample 2 (N = 239 US ethnic minority clients). Strict measurement invariance of the factor structure was observed across the two samples and distinctive correlational patterns with therapeutic process measures were found.Conclusion: The BrAS provides new insights on how sensitivity to ethnic-cultural topics can be targeted along its concrete features, and is a promising tool for conceptualizing culturally sensitive mental healthcare assessment.

Addressing cultural topics during psychotherapy: Evidence-based do's and don'ts from an ethnic minority perspective.

OBJECTIVE: Broaching-i.e., a counsellor's effort to install meaningful conversations in psychotherapy concerning one's cultural identity-is a strong predictor of positive treatment outcomes and client satisfaction, especially for minority-identified clients. Despite this understanding, the broaching literature has struggled to translate broaching principles into practical recommendations for specific behaviours and skills. The current study therefore explores the effects of broaching approaches by the therapist (i.e., direct, indirect and avoidant approach) about cultural topics including ethnicity, religion, gender expression and socioeconomic status on clients' perception of (1) the multicultural orientation of the therapist and (2) the frequency of microaggressions during therapy. METHOD: These research questions were investigated in a sample of ethnic minority clients (N = 231) who followed at least one session of mental healthcare counselling during the last 12 months. RESULTS: Findings show that indirect broaching is the overall most favourable approach, whilst avoidant broaching is consistently negatively associated with all therapy-related outcome measures. CONCLUSION: The results lay the basis for practical guidelines for broaching in psychotherapy, and provide counsellors with a foundation for having cultural conversations in an effective and respectful manner.

Pneumatic femoral broaching decreases post-operative subsidence of a cementless taper-wedge stem.

PURPOSE: Stem subsidence is a known cause of early failure in cementless total hip arthroplasty (THA). The aim of this study was to determine the usefulness of pneumatic femoral broaching in preventing post-operative subsidence of a proximally porous-coated, taper-wedge stem. METHODS: We reviewed 169 cases of primary THA with a single taper-wedge stem. Eighty THAs performed using pneumatic broaching were compared with 89 THAs performed using manual broaching in terms of postoperative canal fill ratio (CFR) at three levels, stem subsidence at one year post-operation, and stem fixation at latest follow-up (median, 24 months). RESULTS: The median CFRs were higher in the pneumatic group than in the manual group at all levels (p < 0.05). The median stem subsidence at one year after THA was lower in the pneumatic group than in the manual group (0.2 mm vs. 0.6 mm, p = 0.007). A multivariate analysis determined a decreased CFR at 60 mm below the lesser trochanter and the manual broaching as independent factors affecting post-operative stem subsidence. At the latest follow-up, all stems showed stable fixation by bone ingrowth in both groups. CONCLUSION: Our results showed that the pneumatic broaching device was useful in maximizing the mediolateral canal filling and initial stability and minimizing the subsidence of taper-wedge stems.

Experimental Study on the Performance of Hydraulic Vibration Assisted Broaching (HVAB) Based on Piezoelectric Sensors.

In order to improve the keyway broaching process and verify the feasibility of vibration-assisted broaching process, an experimental study on a novel hydraulic vibration assisted broaching (HVAB) system with double-valve electro-hydraulic exciter (DVEHE) is proposed in this paper. The performances of HVAB at different excitation frequencies were compared from three aspects: (a) the cutting force under the different vibration frequencies, (b) the surface roughness of the workpiece, and (c) the flank face wear of the tool. For precision on-line measurement of larger broaching forces, four piezoelectric sensors were fixed on the broaching machine. The experimental results show that HVAB can effectively improve the performance of the broaching process, approximately reduce the broaching force by as much as 9.7% compared to conventional broaching (CB) and improve the surface quality of workpiece. Some explanations are offered to support the observations.

Preparation of the Femoral Bone Cavity for Cementless Stems: Broaching vs Compaction. A Five-Year Randomized Radiostereometric Analysis and Dual Energy X-Ray Absorption Study.

BACKGROUND: Short-term experimental and animal studies have confirmed superior fixation of cementless implants inserted with compaction compared to broaching of the cancellous bone. METHODS: Forty-four hips in 42 patients (19 men) were randomly operated using cementless hydroxyapatite-coated Bi-Metric stems. Patients were followed with radiostereometric analysis at baseline, 6 and 12 weeks, 1, 2, and 5 years, and measurements of periprosthetic bone mineral density at baseline, 1, 2, and 5 years. Complications during the study period and clinical outcome measures of Harris Hip Score were recorded at mean 7 years (5-8.8) after surgery. RESULTS: Absolute migrations of medio/lateral translations between the broaching group and the compaction group of mean 0.14 mm (standard deviation [SD] 0.10) vs mean 0.30 mm (SD 0.27) (P = .01) at 1 year, and of mean 0.13 mm (SD 0.10) vs 0.34 mm (0.31) (P = .01) at 5 years were different. Absolute valgus/varus rotations of mean 0.12° (SD 0.13°) in the broaching group were less than mean 0.35° (0.45°) in the compaction group (P < .01) at 1 year, but at 5 years no difference was observed (P = .19). Subsidence and retroversion were similar between groups at all follow-ups (P > .13). The compaction group had significantly less bone loss than the broaching group in Gruen zone 3 (distal-lateral to the stem) at 1 and 5 years. No further differences in bone mineral density changes were found between groups up to 5 years after surgery. Complications throughout the period and clinical outcome measures of Harris Hip Score were similar at 7 years (5-8.8) after surgery. CONCLUSION: We found increased migration when preparing the bone with compaction compared with broaching in cementless femoral stems.

Broaching body size and sizeism: Input from specialized clinicians.

Broaching issues of identity and power with clients in the context of their mental health care is affirmed as an effective multicultural and social justice counseling skill by a growing evidence base. Considerations for broaching body size, including size difference and sizeism, with clients has not yet been studied, thus clinicians lack guidelines for facilitating these conversations. In this consensual qualitative research study, we present themes involved in broaching body topics based on our interviews with nine clinicians specialized in treating clients with eating disorders and body-related counseling concerns. Themes addressed counselor development, conceptualization of broaching, clinical-decision-making, practice, and impact of broaching body topics in session. Clinicians identified professional and personal developments they pursued and would advocate for training future clinicians to better serve clients. Descriptions of unique and shared aspects of broaching clients' intersectionality and body-size specifically depict avenues for tailoring broaching conversations. Specific examples of effective and ineffective broaching conversations, including language used and psychoeducational components, provide recommendations for practice and connect to observed impacts on the client, counselor, and counseling process.

Design and Verification of a Metaphyseal Filling Stem for Total Hip Arthroplasty Based on Novel Measurements of Proximal Femoral Anatomy.

Background: Cementless metaphyseal filling stems rely on fixation in the medial-to-lateral and anterior-to-posterior (AP) planes. The purpose of this preclinical study was to develop Insignia, a new metaphyseal filling system to match the anatomy of the proximal femur, and then compare it to clinically successful stems in multiple simulations. Methods: In this preclinical study, the geometry of the proximal femur in the AP plane among 1321 healthy subjects was evaluated using computed tomography. This data was then used to design insignia. Preclinical studies were performed to compare the broaching effort required to prepare a canal using this system, assess the reliability of seating heights for the stem, and compare in vitro micromotion testing of the stem under simulated stair climb activity. Results: The proximal femur decreased approximately 50% in the AP plane spanning 20 mm above the lesser trochanter to 30 mm below the lesser trochanter. Additional bench top testing was performed, and the new stem system was found to demonstrate significantly reduced broaching effort (average 6 vs 29 hits, P-value = .000), reliable seating heights on stem placement, and 70% less proximal micromotion on 10,000-cyclic testing (P < .05) compared to another clinically successful metaphyseal filling stem. Conclusions: The AP dimension of the proximal femur decreases nearly 50% throughout its length. Metaphyseal filling stems that match the AP anatomy of the proximal femur may require fewer hits during broaching, yield reproducible seating heights, and reduce micromotion on cyclic testing.

Use of an Automated Surgical Impactor Reduces Femoral Broaching Time in Direct Anterior Approach Total Hip Arthroplasty: Results From a Randomized, Multicenter Study.

Background: Impaction in total hip arthroplasty has typically been conducted using a mallet. A surgical automated impactor has been developed with the goal of reducing surgeon variability, fatigue, and injury. There is also potential to reduce the variability of each impaction step in which automated impaction is used, through reproducible and consistent application of force. Methods: Patients were randomized into either the mallet control group, or the automated impaction study group (1:1 randomization). The primary endpoint analysis was conducted to demonstrate that femoral broaching time (in minutes) with an automated impactor is noninferior to femoral broaching time with manual instruments (mallet) under a noninferiority (NI) margin of 1.25 minutes, with a subsequent test of superiority. A total of 218 patients were randomized and treated (109 in each group). Results: Mean femoral broaching time was 5.8 minutes in the automated impaction study group (automated), and 8.1 minutes in the mallet control group (mallet), a 28.4% reduction (P = .0005). However, there was not a difference in surgery duration between the groups. Three fractures were reported in the mallet group and 1 in the automated group. Conclusions: In this randomized multicenter study, an automated impactor was shown to reduce femoral broaching time in primary total hip arthroplasty, with no increase in fractures, but no decrease in operating room time was noted.

Energy expenditure of femoral broaching in direct anterior total hip replacements-Comparison between manual and automated techniques.

INTRODUCTION: Little information is known regarding the energy expenditure of the surgeon during total hip arthroplasty (THA). We sought to compare the energy expenditure associated with femoral broaching using two techniques: manual and automated. METHODS: We recorded energy expenditure, minute ventilation, heart rate, and total broaching time of a single surgeon while broaching the femoral canal during direct anterior THA using two different techniques: Manual broaching (n = 26) and automated broaching (n = 20). RESULTS: Manual broaching required a longer time than automated broaching (6.1 ± 1.1 vs. 3.7 ± 0.9 min; p < 0.001) with an increase in energy expenditure (32.6 ± 7.0 vs. 16.0 ± 7.1 Calories; p < 0.001). Heart rate was higher with manual broaching (99.4 ± 9.8 vs. 90.1 ± 9.8 beats per min; p = 0.003), along with minute ventilation (36.5 ± 7.0 vs. 30.3 ± 5.8 L/min; p = 0.003). There were no intraoperative complications. CONCLUSIONS: Automated femoral broaching during THA can decrease the energy expenditure of broaching by 50% and time of broaching by 40%, when compared to manual technique. CLINICAL TRIAL REGISTRATION: This research was not a clinical trial.

Does Powered Femoral Broaching Compromise Patient Safety in Total Hip Arthroplasty?

Background: During manual broaching (MB) in total hip arthroplasty (THA), off-axis forces delivered to the proximal femur and broach malalignment can lead to fractures and cortical perforations. Powered broaching (PB) is a novel alternative that delivers consistent impaction forces and reduces workload. This is the first large-scale study to compare intraoperative and 90-day rates of periprosthetic femur fractures (PFFs) and perforations in THA performed using MB vs PB. Methods: Our institutional database was reviewed for all patients undergoing primary cementless direct anterior THA from 2016 to 2021. Three surgeons performing 2048 THAs (MB = 800; PB = 1248) using the same stem design were included. PFFs and perforations within 90 days of the index procedure were compared. Differences in length of surgery and demographics were assessed. Results: Calcar fractures occurred in <1% of patients (PB [0.96%, 12/1248] vs MB [0.25%, 2/800]; P = .06). Rates of trochanteric fractures did not differ (PB = 0.32% [4/1248] vs MB = 0.38% [3/800]; P = .84). Cortical perforations occurred in 0.24% (3/1248) of the PB cohort and in 0.75% (6/800) of the MB cohort (P = .09). No revisions due to aseptic loosening or PFF occurred within 120 days of surgery. Conclusions: Our single-center experience with powered femoral broaching in THA demonstrates PB is a safe and efficient means of performing direct anterior THA. Low rates (<1%) of PFF, perforation, and revision can be achieved. Given our positive experience with PB, all surgeon authors utilize PB nearly exclusively for elective primary direct anterior THA.

The Review of Current and Proposed Methods of Manufacturing Fir Tree Slots of Turbine Aero Engine Discs.

This review article presents a summary of currently used and proposed methods of manufacturing fir tree slots of discs in turbine engines. The production of aircraft, including aircraft engines during times of overlapping global economic crises related to the COVID-19 pandemic or the war in Eastern Europe requires a quick response to the changing numbers of passengers and cargo. Similarly, the aviation industry must adapt to these conditions, and thus utilize flexible production methods allowing for a quick change in the design or type of a given part. Due to the constant adoption of new materials for the most critical aero engine parts and the necessity of complying with environmental regulations, it is necessary to search for new methods of manufacturing these parts, including fir tree slots. As an alternative to currently used expensive and energy-intensive broaching, many manufacturers try to implement creep feed grinding CFG or contour milling. However, other manufacturing methods, thus far rarely used for crucial machine parts such as WEDM, ECDM or AWJ, are gaining more and more popularity in the aviation industry. This article presents the advantages and shortcomings of these methods in the context of manufacturing fir tree slots.

Broaching partially-shared identities: Critically interrogating power and intragroup dynamics in counseling practice with trans people of Color.

Background: Much of the literature on transgender and nonbinary (TGNB) experiences in counseling focuses on White experiences with few recommendations for trans people of Color (TPOC). Research suggests mental health care providers lack intersectional sensitivity with TPOC, lack knowledge of TGNB issues and engage in microaggressive behaviors, notably with Queer-identified clinicians. Aim: To explore issues of power and privilege in the counseling relationship with Queer-identified clinicians and apply the multidimensional model of broaching behavior with TGNB clients of Color. Method: A critical review of conceptual and empirical literature focusing on the interaction and impact of client and clinician race, gender, and sexual/affectional identities in the counseling relationship is presented. Informed by the authors' counseling experiences and respective positionalities as a Black Queer ciswoman and a White Queer transman, the multidimensional model of broaching behavior is applied to a composite case vignette. Results: The model provides a practical tool to facilitate critical conversations of power, privilege and identity in the counseling relationship. Conclusion: With a dearth of scholarship addressing the role of cisgender or White privilege in the counseling relationship, this article outlines strategies to broach issues partially-shared identities with TGNB clients of Color. Recommendations for culturally informed counseling practice, supervision and research are also provided.

Assessment of a Bionic Broach Implanted with Nylon Fibers.

The optimization of a broach surface is of great significance to improve the cutting performance of the tool. However, the traditional optimization method (surface texture, coating, etc.) destroys the stress distribution of the tool and reduces the service life of the tool. To avoid these problems, four kinds of flocking surfaces (FB1, FB2, FB3, and FB4), imitating the biological structure of Daphniphyllum calycinum Benth (DCB), were fabricated on the rake face of the broach by electrostatic flocking. The broaching experiment, wettability, and spreading experiment were then conducted. Moreover, the mathematical model of the friction coefficient of the bionic broach was built. The effect of broaches with different flocking surfaces on the broaching force, chip morphology, and surface quality of workpieces was studied. The results indicate that the flocked broaches (FB) with good lubricity and capacity of microchips removal (CMR) present a smaller cutting force (Fc) and positive pressure (Ft) compared to the unflocked broach (NB), and reduce the friction coefficient (COF). The chip curl was decreased, and the shear angle was increased by FB, which were attributed to the function of absorbing lubricant, storing, and sweeping microchips. Its vibration suppression effect enhanced the stability in the broaching process and improved the surface quality of the workpiece. More importantly, the FB2 with the most reasonable fluff area and spacing exhibited the best cutting performance. The experimental conclusions and methods of this paper can provide a new research idea for functional structure tools.

Study on the Control Method of Sidewall Taper in Electrolytic Broaching of Micro Multi-Grooves.

Micro multi-grooves are important functional structures widely used in new heat exchanger types, chemical reactors, and other applications. Electrolytic broaching is an efficient and low-cost technology for processing micro multi-grooves. In the conventional electrolytic broaching of multi-grooves, the cathode tools are usually designed as a wedge-shaped tooth structure array with a constant tooth width, and the sidewalls are covered with insulating layers. The machined groove sidewall is always tapered because of stray current corrosion, which strongly affects the groove contour accuracy. Cathode tools with variable tooth width structures are proposed to solve this problem. Based on the simulation results of the electrolytic broaching anode forming process, the optimal front tooth width is obtained through the golden section optimization method, and comparative tests of the conventional and optimized cathode tools were carried out. At an electrochemical broaching feed rate of 120 mm/min, array microgrooves with widths of about 550 µm and depths of about 520 µm were processed. With the optimized variable tooth width tool, the sidewall tapers of the grooves were reduced from 7.254° to 0.268°. The experimental results verify the effectiveness of the simulation and cathode structure optimization.

Estimation of Drag Finishing Abrasive Effect for Cutting Edge Preparation in Broaching Tool.

In recent years, cutting edge preparation became a topic of high interest in the manufacturing industry because of the important role it plays in the performance of the cutting tool. This paper describes the use of the drag finishing DF cutting edge preparation process on the cutting tool for the broaching process. The main process parameters were manipulated and analyzed, as well as their influence on the cutting edge rounding, material remove rate MRR, and surface quality/roughness (Ra, Rz). In parallel, a repeatability and reproducibility R&R analysis and cutting edge radius re prediction were performed using machine learning by an artificial neural network ANN. The results achieved indicate that the influencing factors on re, MRR, and roughness, in order of importance, are drag depth, drag time, mixing percentage, and grain size, respectively. The reproducibility accuracy of re is reliable compared to traditional processes, such as brushing and blasting. The prediction accuracy of the re of preparation with ANN is observed in the low training and prediction errors 1.22% and 0.77%, respectively, evidencing the effectiveness of the algorithm. Finally, it is demonstrated that the DF has reliable feasibility in the application of edge preparation on broaching tools under controlled conditions.

Ten-year comparison of two different techniques for femoral bone cavity preparation-broaching versus compaction in patients with cementless total hip arthroplasty : a randomized radiostereometric study of 30 total hip arthroplasties in 15 patients operated bilaterally.

AIMS: Femoral bone preparation using compaction technique has been shown to preserve bone and improve implant fixation in animal models. No long-term clinical outcomes are available. There are no significant long-term differences between compaction and broaching techniques for primary total hip arthroplasty (THA) in terms of migration, clinical, and radiological outcomes. METHODS: A total of 28 patients received one-stage bilateral primary THA with cementless femoral stems (56 hips). They were randomized to compaction on one femur and broaching on the contralateral femur. Overall, 13 patients were lost to the ten-year follow-up leaving 30 hips to be evaluated in terms of stem migration (using radiostereometry), radiological changes, Harris Hip Score, Oxford Hip Score, and complications. RESULTS: Over a mean follow-up period of 10.6 years, the mean stem subsidence was similar between groups, with a mean of -1.20 mm (95% confidence interval (CI) -2.28 to -0.12) in the broaching group and a mean of -0.73 mm (95% CI -1.65 to 0.20) in the compaction group (p = 0.07). The long-term migration patterns of all stems were similar. The clinical and radiological outcomes were similar between groups. There were two intraoperative fractures in the compaction group that were fixed with cable wire and healed without complications. No stems were revised. CONCLUSION: Similar stem subsidence and radiological and clinical outcomes were identified after the use of compaction and broaching techniques of the femur at long-term follow-up. Only the compaction group had intraoperative periprosthetic femur fractures, but there were no long-term consequences of these. Cite this article: Bone Jt Open 2021;2(12):1035-1042.

The influence of broach design on bone friction and osseodensification in total hip arthroplasty.

BACKGROUND: The process of cavity preparation by broaching has an impact on the primary stability of uncemented hip stems and on the periprosthetic fracture risk. Osseodensifying broaches may increase primary stability, but have the potential to raise cortex strains and facilitate fracture. The aim of this study was to determine the influence of broach design on the forces acting during broaching, on the microstructure of the broached bone bed and the amount and depth of osseodensification. METHODS: Broach models representing compaction, blunt extraction and sharp extraction broaches, were used for quasi-static simulation of femoral cavity preparation on bovine trabecular bone cuboids. Broaching forces were measured and micro-computed tomography scans performed prior and after testing. Friction coefficients during broaching, bone densification parameters and size of the debris particles pushed into the bone were determined. FINDINGS: Friction coefficients during sharp extraction exceeded those during compaction and blunt extraction broaching (by 38% and 37%, P < .001). Total bone densification was enhanced for compaction and blunt extraction compared to sharp extraction broaching (increase of 121% and 117%, P = .005), resulting from higher densification depths for compaction (P = .001) and higher maximum densification for blunt extraction broaching (P = .008), with the latter producing fewer large particles than compaction broaching (P = .005). INTERPRETATION: Higher friction coefficients indicate a decreased periprosthetic fracture risk with sharp extraction broaches for equal implantation forces. The blunt extraction and compaction designs investigated densified the bone to a similar extent. Blunt extraction broaching may support better osseointegration due to smaller bone debris particles.

Modification of regional bone mineral density due to femoral rasping in cementless proximally fixed total hip arthroplasty.

BACKGROUND: Three-dimensional planning (3DP) in total hip arthroplasty using computed tomography (CT) to analyze bone mineral density (BMD) at the stem-femur interface has a high reported accuracy and excellent mid-term results in the literature. However, 3DP does not take into account the effect of femoral rasping on BMD distribution within the rasped cavity. Characterizing the impact of femoral rasping on BMD may help avoid mechanical failures, but this data is not accurately investigated. Therefore, we set out a cadaveric study to identify if: (1) Femoral rasping modified regional BMD in areas considered critical for bone anchorage of cementless metaphyseally fixed anatomic stems. (2) In areas of bone-implant contact with an initial high BMD, does femoral rasping increase BMD? HYPOTHESIS: Femoral rasping increases BMD in some zones considered critical for bone anchorage of cementless metaphyseally fixed anatomic stems within the rasped femoral cavity. METHODS: Four cadaveric femurs were selected to undergo a rasping procedure similar to surgical techniques used for metaphyseally fixed anatomic stems. Images of femurs before and after rasping were obtained with a micro-CT scanner (pixel size 35µm). BMD values before and after rasping were compared in a trabecular bone ring of 3mm thickness around the cavity created by the rasps, in a region extending 3cm above and 2cm below the middle of the lesser trochanter. RESULTS: Average BMD increased significantly after rasping in 3 of the 4 femurs (13% (0.27 to 0.30) (p=0.004)), 12% (0.32 to 0.36 (p=0.034)) and 15% (0.4 to 0.46 (p=0.001)), while there was no significant variation in the last femur (0.32 to 0.32 (p>0.05)). Increases in regional BMD were significantly higher in the lateral and medial areas, as well as in the most distal femoral regions. There were significantly lower variations of BMD in regions with initially higher BMD. DISCUSSION: Current opinion considers trabecular bone debris from femoral rasping to have an impact on final stem position and outcome. Our study has demonstrated an overall positive effect of femoral rasping on BMD in the rasped cavity. Understanding this in the context of 3DP may help avoid mechanical failures such as, suboptimal implant fit, fill, and stability as well as femoral fractures during stem implantation. LEVEL OF EVIDENCE: IV, Prospective in vitro study.