Cementless Tapered-Wedge Stem Length Affects the Risk of Periprosthetic Femoral Fractures in Direct Anterior Total Hip Arthroplasty

Risk Factors for Periprosthetic Femoral Fractures After Cementless Total Hip Arthroplasty

BACKGROUND

The present study aimed to identify the risk factors of periprosthetic femoral fracture (PFF) after cementless total hip arthroplasty and rank them based on importance.

METHODS

The age, sex, body mass index (BMI), osteoporosis, canal flare index (CFI), canal bone ratio (CBR), canal calcar ratio (CCR), stem design, and stem canal fill ratio (P1, P2, P3, and P4) of the proximal femoral medullary cavity of 111 total hip arthroplasty patients who had PFF and 388 who did not have PFF were analyzed. Independent-samples student t-tests were used for continuous variables, and Chi-square tests were used for categorical variables. The importance rankings of influencing factors were assessed using a random forest algorithm. Dimensionally reduced variables were then incorporated into a binary logistic regression model to determine the PFF-related risk factors.

RESULTS

The mean age, BMI, CBR, CCR, and incidence of osteoporosis were higher in cases of PFF (all P < .001), while the mean CFI, P1, P2, P3, and P4 were lower in cases of PFF (P < .001, P = .033, P = .008, P < .001, and P < .001, respectively). Additionally, the stem design was also statistically associated with PFF (P < .001). Multivariate logistic regression revealed that advanced age, higher BMI, osteoporosis, stem design, lower CFI, higher CBR, higher CCR, lower P1, lower P2, lower P3, and lower P4 were the risk factors of PFF (P < .001, P < .001, P < .001, P < .001, P < .001, P = .010, P < .001, P = .002, P < .001, P < .001, and P = .007, respectively). The ranked importance of the risk factors for PFF was P3, CFI, osteoporosis, CBR, age, P4, P1, stem design, CCR, BMI, and P2.

CONCLUSIONS

Lower P3, lower CFI, osteoporosis, higher CBR, advanced age, lower P4, lower P1, stem design, higher CCR, higher BMI, and lower P2 increased the risk of PFF.

Callus formation after total hip arthroplasty using a short tapered-wedge stem

OBJECTIVE

The incidence of periprosthetic fractures after total hip arthroplasty using a short tapered-wedge stem is high. Callus formation preceding this fracture, which indicates postoperative stress fracture around the stem, has been reported. However, previous studies on postoperative callus are limited. Hence, the current study aimed to evaluate the prevalence and risk factors of postoperative callus after total hip arthroplasty with a short tapered-wedge stem.

MATERIALS AND METHODS

This retrospective study included 127 patients who underwent total hip arthroplasty using a cementless short tapered-wedge stem. The depth of stem insertion was measured as the distance from the lateral corner of the stem to the most medial point of the lesser trochanter along the body axis. Postoperative callus was defined as a bridging callus on the lateral femoral cortex at the distal end of the porous coating of the stem. Plain radiography was performed before surgery and immediately and at 1, 3, and 6 months after surgery to assess postoperative callus. Univariate and multivariate logistic regression analyses were performed to identify the risk factors for PC.

RESULTS

In total, 60 (47.2%) of 127 patients presented with postoperative callus. Multivariate logistic regression analysis with postoperative callus as the dependent variable revealed that the stem depth at 1 month after total hip arthroplasty (odds ratio, 1.14; 95% confidence interval, 1.04-1.24, p = 0.002) was a significant and independent risk factor of postoperative callus.

CONCLUSION

Deep insertion of a short tapered-wedge stem is a risk factor for postoperative callus.

A comparison of cemented femoral fixation via anterior versus posterior approach total hip arthroplasty: an analysis of 60,739 total hip arthroplasties

BACKGROUND

Anterior approach total hip arthroplasty (THA) decreases the rate of dislocation but increases femoral-sided complications in the way of periprosthetic fractures and component loosening. A cemented prosthesis may reduce femoral-sided complications and improve the risk:benefit profile of anterior approach THA.

METHODS

Data from the Australian National Joint Replacement Registry were analysed for patients undergoing primary THA via the anterior or posterior approach using a cemented polished femoral stem from January 2015 to December 2021. The primary outcome measure was the cumulative percent revision (CPR) for all causes and CPR for femoral component loosening and fracture. The CPR for the primary outcome measures were compared between the anterior and posterior approach and adjusted for age, sex, ASA score, BMI and femoral head size.

RESULTS

The study included 60,739 THAs with cemented stems (10,742 anterior, 49,997 posterior). The rate of revision of the anterior versus the posterior approach did not significantly differ (HR 0.87 (95% CI, 0.74-1.03), p = 0.100). Anterior approach THA had a significantly higher rate of revision for femoral component loosening (HR 5.06 [95% CI, 3.08-8.30], p < 0.001); and a decreased rate of revision for infection (HR 0.59 [95% CI, 0.43-0.81], p = 0.001) and dislocation/instability (HR 0-3 months 0.48 [95% CI, 0.27-0.83], p = 0.008; HR >3 months 0.30 [95% CI, 0.15-0.61], p < 0.001). There was no difference in the rate of revision surgery for fracture between the 2 approaches (HR 1.01 [95% CI, 0.71-1.43]), p = 0.975).

CONCLUSIONS

There is no significant difference in overall revision rates with cemented femoral fixation performed with an anterior or posterior approach. Cemented fixation performed with the anterior approach partly mitigates femoral complications with no difference in the revision rate for fracture but an increased rate of femoral component loosening.

Early- to mid-term outcome of a short, cementless, titanium, flat, tapered stem for primary total hip arthroplasty: an independent series

INTRODUCTION

This study aims to: (1) describe perioperative complications amongst patients who underwent primary total hip arthroplasty (THA) using a short cementless, titanium, flat, tapered stem; (2) estimate this stem's early- to mid-term survival; (3) identify factors associated with revision arthroplasty; and (4) describe femoral remodelling at minimum 6 years postoperatively.

METHODS

A retrospective review of consecutive patients who underwent THA using a Taperloc Microplasty stem (Zimmer-Biomet, Warsaw, Indiana, USA) with minimum 2-year follow-up was performed. Surgeries were performed by 1 of 6, non-designer, arthroplasty surgeons between 2014 and 2018. Outcomes included perioperative complications including revision arthroplasty, and survival. Cox analysis was used to analyse the effect of different factors on risk of revision arthroplasty. Radiographs with 6-year follow-up served to describe femoral remodelling.

RESULTS

In 1205 patients, followed for 5.1 ± 1.4 years, the incidence of perioperative complication was 5.2% for which 29 patients (2.4%) required revision arthroplasty. The 5- and 7-year survival rates were 97.8% (95% CI, 96.9-98.5) and 97.0% (95% CI, 95.6-98.0), respectively. The only factor associated with revision arthroplasty was proximal femur morphology, as per Dorr classification (HR 1.24 [95%CI, 1.09-1.41]; p = 0.005). During radiographic assessment, 12% of patients showed ⩾25% of relative change in cortical thickness in Gruen zones 3 or 5. We observed calcar remodelling in 50% of radiographs while 10% showed presence of a pedestal sign.

CONCLUSIONS

The 7-year survivorship of the Taperloc Microplasty stem is within National Institute for Health and Care Excellence (NICE) guidelines. Patients ⩽65 years with osteoarthritis and Dorr A/B femoral morphology may be ideal candidates for THA with this stem. Femoral remodelling is common and not associated with adverse outcome.

Rectangular Taper Stem Designs Are Associated With a Higher Risk for Periprosthstic Femoral Fractures After Cementless Total Hip Arthroplasty

BACKGROUND

Periprosthetic femoral fractures (PFFs) remain a major concern following cementless total hip arthroplasty (THA). This study aimed to evaluate the association between different types of cementless tapered stems and the risk of postoperative PFF.

METHODS

A retrospective review of primary THAs performed at a single center from January 2011 to December 2018 included 3,315 hips (2,326 patients). Cementless stems were classified according to their design. The incidence of PFF was compared between flat taper porous-coated stems (type A), rectangular taper grit-blasted stems (type B1), and quadrangular taper hydroxyapatite-coated stems (type B2). Multivariate regression analyses were performed to identify independent factors related to PFF. The mean follow-up duration was 61 months (range, 12 to 139). Overall, 45 (1.4%) postoperative PFFs occurred.

RESULTS

The incidence of PFF was significantly higher in type B1 stems than in type A and type B2 stems (1.8 versus 0.7 versus 0.7%; P = .022). Additionally, more surgical treatments (1.7 versus 0.5 versus 0.7%; P = .013) and femoral revisions (1.2 versus 0.2 versus 0%; P = .004) were required for PFF in type B1 stems. After controlling for confounding variables, older age, diagnosis of hip fracture, and use of type B1 stems were significant factors associated with PFF.

CONCLUSION

Type B1 rectangular taper stems were found to have higher risks for postoperative PFF and PFF requiring surgical management than type A and type B2 stems in THA. Femoral stem geometry should be considered when planning for cementless THA in elderly patients who have compromised bone quality.

Low Risk of Fracture Using a Cementless Triple-tapered Collared Femoral Stem with Automated Impaction in Direct Anterior Approach Total Hip Arthroplasty

INTRODUCTION

Direct anterior approach (DAA) total hip arthroplasty (THA) has been associated with increased periprosthetic femoral fracture (PFF) risk. The aim of our study was to evaluate the fracture risk utilizing a triple tapered, collared stem with automated impaction through the anterior approach.

METHODS

We retrospectively reviewed consecutive DAA THA procedures at a single institution performed by four experienced DAA THA surgeons between 2019 and 2021. We collected data on age, sex, body mass index, preoperative diagnosis, and intraoperative and early postoperative PFF within 6 weeks postoperatively. Preoperative radiographs were evaluated to determine femoral neck-shaft angle and Dorr classification. We used Wilcoxon Rank sum or Chi-square tests to assess differences between patients who did and did not have PFF. We also evaluated potential risk factors for PFF in unadjusted and adjusted regression analyses. In all, 24 PFFs (1.6%) occurred. There were eighteen fractures (1.2%) recognized and managed intraoperatively (15 calcar, 2 greater trochanter, 1 posterior cortical). There were six PFFs (0.4%) identified postoperatively (5 greater trochanter, 1 diaphyseal), of which 1 required a revision surgery.

RESULTS

Identified risk factors for fracture in adjusted regression models included women (Odds Ratio (OR)=2.76, P=0.047), preoperative coxa valga (OR= 4.54, P=0.005), and coxa vara (OR=2.85, P=0.03).

CONCLUSION

The incidence of periprosthetic femoral fractures is low using a triple tapered, collared cementless femoral stem with automated impaction through the DAA. Our findings agree with previous reports that have demonstrated women and preoperative valgus neck angle are risk factors for PFF.

Clinical outcomes of DAA and related techniques in hip arthroplasty

Total hip arthroplasty (THA) has been one of the most successful surgical interventions in recent memory and is nicknamed by some the "Surgery of the Century". Over the past decade, there has been a drastic change in THA management with the rise of the direct anterior approach both globally and in the USA market. While many would remark that this has been driven by false marketing, it is clear that the direct anterior approach can be an effective and safe way to perform a THA.It is the goal of this review to highlight evidence of its outcomes and clinical advantages, in particular, how it can decrease dislocation, even in high-risk individuals, and result in faster recovery in the early postoperative period with decreased muscular inflammation. We will also highlight its major disadvantages, including but not limited to increased wound complications and risk for periprosthetic fracture. Hopefully, this review will provide up-to-date information on the current state of the direct anterior approach and provide recommendations on patients that would be optimal candidates for this technique.

Recent advances in the direct anterior approach to total hip arthroplasty: a surgeon's perspective

INTRODUCTION

The direct anterior approach (DAA) has its origins in the first and oldest approach for hip replacement in the literature, but at the same time it would not be fanciful to suggest its increasing popularity as the latest approach for hip replacement procedures, especially among younger surgeons. However, in a geographical context, the DAA is not considered the major approach in most countries. Moreover, the term DAA encompasses numerous variations in terms of technique.

AREAS COVERED

In this narrative review, we describe our recent experience of advances in the DAA in terms of improved techniques and devices, along with some of its disadvantages. Also, we express our perspective on its future application.

EXPERT OPINIONS

The DAA is established as one of exemplary approaches to THA. The use of fluoroscopy, the traction table, and appropriate soft tissue management has become essential in the DAA for a safe and trouble-free procedure with adequate patient comfort. With the combination of recent technologies such as robotics, three-dimensional preoperative planning, and artificial intelligence (AI)-based surgeon assist systems, we can look forward to the DAA being performed more efficiently in the future.

Intermediate-Term Survivorship of Total Hip Arthroplasty With a Proximally Coated Tapered-Wedge Femoral Stem: A Retrospective, Multi-Center Registry Review

BACKGROUND

Short tapered-wedge stems have been used frequently over the past decade, but long-term follow-up data are not readily available in the literature.

METHODS

A retrospective outcomes review was conducted to assess survivorship and clinical outcomes for the TRI-LOCK® Bone Preservation Stem (TRI-LOCK BPS; DePuy Synthes, Warsaw, IN, USA), a proximally coated, tapered-wedge femoral stem.

RESULTS

In a cohort of 2,040 hips, Kaplan-Meier survivorship estimates (95% CI {confidence interval}; N with further follow-up, where N is the number of hips remaining at each post-operative interval), with survivorship defined as no revision of any component for any reason were 96.6% (92.8%,98.4%; 45) at eight years under the clinical assumption and 98.6% (97.9%,99.1%; 90) at 14 years under the registry assumption. With survivorship defined as stem revision for any reason, estimates were 97.7% (93.7%,99.2%; 45) at eight years under the clinical assumption and 99.2% (98.6%,99.5%; 90) under the registry assumption. Mean Harris Hip Scores and WOMAC scores were 90.08 and 21.98, respectively, at 10 years postoperatively.

CONCLUSION

Our evaluation demonstrates excellent construct and stem survivorship and clinical outcomes at intermediate-term postoperative follow-up.

Taper-wedge stem suitable for anterior approach total hip arthroplasty: Adequate biomechanical reconstruction parameters and excellent clinical outcome at mid-term follow-up

BACKGROUND

The direct anterior approach (DAA) for total hip arthroplasty (THA) is a less invasive and muscle-sparing approach that seems to improve early function and patient satisfaction. Several studies, however, have reported high complication and revision rates due to the technical difficulties related to the femoral preparation.

AIM

To evaluate the usefulness and safety of a new stem equipped with a morphometric design and a size-specific medial curvature in DAA for THA.

METHODS

This retrospective study was based on 130 patients that underwent mini-invasive DAA procedures for THA using the Accolade II stem. A total of 144 procedures were included in the assessment, which was based on postoperative complications, survival rates, functional parameters, and patient related outcomes.

RESULTS

Overall complications were recorded in 6 procedures (4.2%). There were no complications related to the stem implantation and no intraoperative fractures. Only one patient was revised for deep infection. On radiographs, biomechanical hip reconstruction was satisfactory and no stem showed any subsidence greater than 2 mm. Full osseointegration based on Engh scores was seen in all of the implanted stems. Median Harris hip score at final follow-up was 99 points (range 44-100 points), which resulted excellent in 91.3% of patients. The median values of the osteaorthritis outcome score ranged from 87.5 to 95.

CONCLUSION

The mid-term positive outcomes and low complication rate in our consecutive series of patients support the safety and suitability of this new stem design in DAA for THA.

Hip Arthroplasty Femoral Stem Designs and Their Association With Early Postoperative Periprosthetic Femoral Fractures

BACKGROUND

Periprosthetic femoral fractures (PFFs) in total hip arthroplasty (THA), especially those in contact with the diaphyseal stem, carry high morbidity. This study evaluated how stem design influences the risk of early Vancouver B PFF or other PFF requiring operative intervention after THA.

METHODS

A multicenter, retrospective study of 3,433 primary cementless THAs performed from 2014 to 2021 included 2,302 single-taper (micro M/L [n = 1,169]; M/L [n = 1,133]) and 1,131 double-taper (fit-and-fill [n = 420]; compaction-collared [n = 711]) stems. Mean follow-up was 2.2 years (range, 0.3 to 6.5 years). Primary outcomes were Vancouver B and surgically treated postoperative PFFs among differing femoral stems. Secondary outcomes included rates of intraoperative and postoperative Vancouver A and C PFFs.

RESULTS

Forty five postoperative PFFs (1.3%) occurred within 8.8 weeks (median), 25 of which were Vancouver B (0.7%) and 20 total PFFs that required operative intervention (0.6%). Compaction-collared stems had a decreased risk of Vancouver B (hazard ratio 0.18, 95% confidence interval: 0.03-0.97 P = .044) and any surgically treated PFF (hazard ratio 0.10, 95% confidence interval: 0.01-0.95; P = .037). Intraoperative PFFs were most common with fit-and-fill stems (3.6%, P < .001) and Vancouver A with compaction-collared stems (1.8%, P < .001). The cohort with PFF had a higher Charlson comorbidity index (P = .004), more women (P = .001), more Dorr A or C femora (P = .013), and more posterior or lateral surgical approaches compared to those without PFF (P ≤ .001).

CONCLUSION

After controlling for confounding variables, compaction-collared stems had a significantly lower risk of postoperative Vancouver B and PFF requiring operative treatment than single-taper and double-taper stems.

A smaller femoral stem is needed for asian females

BACKGROUND

Current femoral implants are manufactured based on Western anatomical structures and may be too large for smaller physiques, such as those of Asian females. This study reviewed the femoral stem size distribution used in a high-volume total hip arthroplasty (THA) practice and evaluated malalignment in patients receiving a size one implant.

MATERIALS AND METHODS

A consecutive cohort of female patients self-reported as Asian (257 patients, 331 hips) or Caucasian (158 patients and 190 hips) were retrospectively evaluated. A single femoral stem type was used in all cases, performed by a single surgeon. Global hip offset (GHO) and leg length difference (LLD) were measured before and 6 weeks following THA. Differences between races were evaluated through Mann-Whitney U tests and chi-squared tests for continuous and categorical variables, respectively.

RESULTS

The proportion of size one implants was higher amongst Asian patients (20.5%) than Caucasian patients (2.6%) (p < 0.001). A LLD greater than 6 mm was noted in 24.6% of size one patients and 11.4% of all other sizes (p = 0.010). Varus malalignment occurred in 47.9% of size one patients and 22.1% of all other sizes (p < 0.001). No fractures occurred in size one patients, and nine fractures (one intraoperative and eight post-operative) occurred in all other sizes (p = 0.258).

CONCLUSION

The high proportion of size one stems required in Asian females and the higher incidence of LLD > 6 mm and varus malalignment suggest a distinct need for smaller femoral implants, especially for Asian females.

Minimum 10-Year Follow-Up of Total Hip Arthroplasty With a Collarless Triple-Tapered Polished Cemented Stem With Line-to-Line Implantation Using a Direct Anterior Approach

BACKGROUND

The Trilliance stem (B. Braun-Aesculap, Tuttlingen, Germany), a novel collarless triple-tapered polished stem, was introduced in 2009. The aim of this study is to evaluate the long-term clinical and radiological results of the Trilliance stem with line-to-line implantation in primary total hip arthroplasty using a direct anterior approach.

METHODS

A consecutive retrospective series of 130 patients (151 hips) who underwent total hip arthroplasty between February 2009 and August 2011 were evaluated for a minimum of 10 years. Of these, 87.4% had a diagnosis of secondary osteoarthritis based on developmental hip dysplasia. Clinical and radiological results, complications were evaluated and survival analysis was performed.

RESULTS

The mean follow-up was 10.7 years (range, 10.0-12.1). Thirteen hips (13 patients, 6.8%) were lost to follow-up. Adequate cementation (Barrack grade A) was achieved in 136 hips (93.8%) 1 week post-operatively. Nearly all (144 hips, 99.3%) had been inserted within the range of 3°. No significant differences were identified between high- (≥30 procedures/year) and low- (<30 procedures/year) volume surgeons. The Kaplan-Meier survival analysis with revision of the femoral component for aseptic loosening, revision of the femoral component for any reason and revision of either component for any reason as the end points, cumulative survivorship was 100.0%, 97.6% (95% confidence interval (CI) 95.4-100.0) and 96.5% (95% CI 93.8-99.3) at 10 years, respectively.

CONCLUSION

The Trilliance stem with line-to-line implantation using a direct anterior approach has an excellent clinical and radiological outcome at a minimum of 10 years' follow-up.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

Varus malalignment of short femoral stem not associated with post-hip arthroplasty fracture

INTRODUCTION

Periprosthetic femoral fractures are an increasingly common post-operative complication of total hip arthroplasty (THA). Though varus malalignment is known to increase fracture risk in standard-length femoral stems, varus malalignment is not as well studied in short stems. Therefore, the purpose of this study was to determine if varus malalignment contributes to early periprosthetic fracture risk in a cementless taper-wedged, short femoral stem.

MATERIALS AND METHODS

This retrospective review included 366 consecutive patients (441 THAs) having undergone THA via anterior approach by a single surgeon between July 2014 and December 2016. All patients received the same short, cementless femoral stem. Femoral component angle was measured on 6-week post-THA weight-bearing radiographs, with malalignment defined as a femoral component angle exceeding 0° ± 3°. Periprosthetic femoral fracture and aseptic loosening occurring within 2 years post-THA were recorded.

RESULTS

The final data analysis included 426 hips with a mean follow-up time of 32.9 ± 10.2 months. Varus and neutral alignment occurred in 84 (19.6%) and 342 (79.9%) of stems, respectively. Three (0.7%) periprosthetic femoral fractures occurred within 2 years, all occurring in patients with neutrally aligned femoral stems. One (0.2%) stem failed due to aseptic loosening and was malaligned.

CONCLUSION

Despite nearly 20% of stems placed in varus alignment, three of the four early complications occurred in a neutrally aligned stem. Based on these results, forceful intraoperative realignment of a short femoral stem with good initial fixation may present an unnecessary increased risk of intraoperative fracture.

Does femoral stem choice influence fracture type or incidence for direct anterior approach total hip arthroplasty?

INTRODUCTION

Despite similar fracture rates, the incidence of intraoperative and post-operative fractures between standard (ST) length and short (SH) femoral stems remains unclear. Therefore, this study compared the incidence of intraoperative and early postoperative fractures between three ST and a single tapered-wedge SH femoral stem.

MATERIALS AND METHODS

Data were retrospectively collected on 1113 patients (1306 hips) having undergone total hip arthroplasty, via the anterior approach on a fracture table, between 2014 and 2019. One surgeon completed all ST procedures (314 hips), using one of three implants without discretion. One surgeon completed all SH procedures (992 hips), using one implant design. Differences between ST and SH groups were evaluated by independent t tests (continuous variables) and Chi-square tests (categorical variables).

RESULTS

Patients in the SH group were significantly older (p < 0.001) and had a lower body mass index (p = 0.001) compared to the ST group. The total number of fractures was 12 (3.8%) and 14 (1.4%) in the ST and SH groups, respectively. The 12 ST fractures occurred intraoperatively, compared to two (0.2%) in the SH group. The remaining seven (0.7%) SH fractures occurred post-operatively. There was no difference in fracture rate between the three ST designs (p = 0.882). Interestingly, five (0.5%) insufficiency fractures were diagnosed in the SH group.

CONCLUSION

The risk of intraoperative and post-operative fractures following anterior total hip arthroplasty may be biased toward ST and SH implants, respectively. These results, along with the presence of five insufficient fractures, identify potential fracture risks and mechanisms for specific implant designs.

Selecting a Press-fit Stem for Total Hip Arthroplasty: The Rationale and Evolution of the Modern Femoral Prosthesis

Noncemented press-fit femoral stems predominate in total hip arthroplasty for all age groups with generally excellent long-term survivorship. The 2021 American Joint Replacement Registry reports that 96% of all elective primary total hip arthroplasties used noncemented femoral implant fixation. 1 Today, there are many styles of press-fit stems, each with supposed benefits, based on a range of design philosophies. Design aspects to consider when selecting a stem are numerous, including stem geometry, stem length, collared or collarless, material properties, and surface structure. Although most stem designs demonstrate excellent results, the differences in stem designs are intimately linked to additional factors such as ease of use/implantation, percentage of surface osseointegration, overall bone removal versus bone stock preservation, subsequent femoral stress shielding, and consideration of complexity of later revision. A surgeon with a broad understanding and appreciation of femoral stem designs should be prepared to select between the multitude of options to best serve individual patients.

Can We Predict Fracture When Using a Short Cementless Femoral Stem in the Anterior Approach?

BACKGROUND

Short cementless femoral stems may allow for easier insertion with less dissection. The use of short stems with the anterior approach (AA) may be associated with a considerable perioperative fracture risk. Our aim was to evaluate whether patient-specific femoral and pelvic morphology and surgical technique, influence the perioperative fracture risk. Furthermore, we sought to describe important anatomical thresholds alerting surgeons.

METHODS

A single-center, multi-surgeon retrospective, case-control matched study was performed. Thirty nine periprosthetic fractures (3.4%) in 1,145 primary AA THAs using short cementless stems were identified. These were matched with 78 THA nonfracture controls for factors known to increase the fracture risk. A radiographic analysis using validated software measured femoral (canal flare index [CFI], morphological cortical index [MCI], and calcar-calcar ratio [CCR]) and pelvic (Ilium-ischial ratio [IIR], ilium overhang, and anterior superior iliac spine [ASIS] to greater trochanter distance) morphologies and surgical techniques (% canal fill). A multivariate and Receiver-Operator Curve (ROC) analysis was used to identify fracture predictors.

RESULTS

CFI (3.7 ± 0.6 vs 2.9 ± 0.4, P < .001) and CCR (0.5 ± 0.1 vs 0.4 ± 0.1, P = .006) differed. The mean IIR was higher in fracture cases (3.3 ± 0.6 vs 3.0 ± 0.5, P < .001). Percent canal fill was reduced in fracture cases (82.8 ± 7.6 vs 86.7 ± 6.8, P = .007). Multivariate and ROC analyses revealed a threshold CFI of 3.17 which was predictive of fracture (sensitivity: 84.6%/specificity: 75.6%). The fracture risk was 29 times higher when patients had CFI >3.17 and II ratio >3 (OR: 29.2 95% CI: 9.5-89.9, P < .001).

CONCLUSION

Patient-specific anatomical parameters are important predictors of a fracture-risk. A careful radiographic analysis would help identify those at a risk of early fracture using short stems, and alternative stem options should be considered.

Risk Factors for Periprosthetic Femoral Fracture in Non-cemented Total Hip Arthroplasty Through the Direct Anterior Approach

Background: Although total hip arthroplasty (THA) performed through the direct anterior (DA) approach is frequently marketed as superior to other approaches, there are concerns about increased risks of intraoperative and early postoperative femoral fracture. Purpose: We sought to assess patient-specific and radiographic risk factors for intraoperative and early postoperative (90-day) periprosthetic femoral fracture (PPFx) following DA approach THA. Methods: We retrospectively reviewed 1107 consecutive, primary, non-cemented DA THAs, performed between April 2009 and January 2015, for intraoperative and early postoperative PPFx. Patients lost to follow-up before 90 days (63), cemented or hybrid THA (52), or early femoral failure for another indication (3) were excluded, yielding 989 hips for analysis. Demographic variables and patient comorbidities were analyzed as risk factors for PPFx. Continuous variables were initially compared with 1-way analysis of variance (ANOVA) and categorical variables with chi-square test. A demographic matched-paired radiographic analysis was performed for femoral stem canal fill and compared using univariate logistic regression. Results: The incidence of perioperative PPFx was 2.02%, including 10 intraoperative and 10 early postoperative fractures. Sustaining a postoperative PPFx was associated with being 70 years old or older with a body mass index (BMI) of less than 25, or with having either osteoporosis or Parkinson disease. Radiographs demonstrated that intraoperative PPFx was associated with stems that filled greater proximally rather than distally. Conclusion: Our cohort study found older age, age over 70 with BMI of less than 25, osteoporosis, and Parkinson disease were associated with increased risk for early postoperative PPFx following DA approach THA. Intraoperative fractures may occur with disproportionate proximal femoral canal fill. Further study can evaluate whether cemented femoral components may mitigate risk in these patient populations.

Short single-wedge stems have higher risk of periprosthetic fracture than other cementless stem designs in Dorr type A femurs: a finite element analysis

BACKGROUND

The use of total hip arthroplasty (THA) femoral stems that transmit force in a favourable manner to the femur may minimise periprosthetic fractures. Finite element analysis (FEA) is a computerised method that analyses the effect of forces applied to a structure with complex shape. Our aim was to apply FEA to compare primary THA cementless stem designs and their association with periprosthetic fracture risk.

METHODS

3-dimensional (3D) models of a Dorr Type A femur and 5 commonly used primary THA cementless stem designs (short single wedge, standard-length single wedge, modular, double-wedge metaphyseal filling, and cylindrical fully coated) were developed using computed tomography (CT) imaging. Implant insertion, single-leg stance, and twisting with a planted foot were simulated. FEA was performed, and maximum femoral strain along the implant-bone interface recorded.

RESULTS

Femoral strain was highest with short single-wedge stem design (0.3850) and lowest with standard-length single-wedge design (0.0520). Location of maximum femoral strain varied by stem design, but not with implant insertion, single-leg stance, or twisting with a planted foot. Strain was as high during implant insertion as with single-leg stance or twisting with a planted foot.

CONCLUSIONS

Our results suggest the risk of intraoperative and postoperative periprosthetic fracture with THA in a Dorr A femur is highest with short single-wedge stems and lowest with standard-length single-wedge stems. Consideration may be given to minimising the use of short single-wedge stems in THA. Implant-specific sites of highest strain should be carefully inspected for fracture.

Low pelvic incidence is a risk factor for intraoperative complications in minimally invasive anterolateral approach for total hip arthroplasty

BACKGROUND

Minimally invasive anterolateral approach (ALA) has gained popularity in recent years as better postoperative functional recovery and lower risk of postoperative dislocation are claimed. However, difficulties for femur exposure and intraoperative complications during femoral canal preparation and component placement have been reported. This study analyses the effect of anatomical factors on difficulties for femoral access and intraoperative complications with a modified minimally invasive ALA.

MATERIAL AND METHODS

310 consecutive patients who had primary unilateral total hip arthroplasty (THA) by single surgeon using same approach and technique, and being suitable for EOS were included. All patients underwent pre- and postoperative standing and sitting full-body EOS acquisitions and pelvic and femoral parameters were measured. All intra- and postoperative complications for femoral preparation and implantation were assessed. Intraoperative complications included femoral fractures and difficulties for femoral exposure.

RESULTS

10 patients (3.2%) had intraoperative femoral fractures (2 greater trochanter, 8 calcar). Difficult access to the proximal femur was reported for 10 other patients (3.2%). Patients with intraoperative complications presented a significantly lower pelvic incidence (PI) than patients without intraoperative complications (mean PI: 39.4° vs. 56.9°, p < 0.001).

CONCLUSIONS

The pelvic incidence can be useful to detect anatomically less favourable patients for THA implantation using ALA.

Early failure of an uncemented femoral stem, as compared to two other stems with similar design, following primary total hip arthroplasty performed with direct anterior approach

INTRODUCTION

An increased risk of early femoral component loosening has been reported using the direct anterior approach (DAA) compared with other common surgical approaches. However, long-term data are scarce. The purpose of this study is: (1) to determine the incidence of early femoral loosening in a high volume, single surgeon's practice utilising the DAA approach; and (2) to examine the effect of stem design and type of coating on aseptic loosening in the early and mid-term postoperative period.

METHODS

A retrospective review of 1650 consecutive patients (1800 hips) who underwent total hip arthroplasty (THA) using the DAA between August 2011 and December 2017 was conducted at our institution. 3 types of uncemented femoral stems (Quadra-S, Avenir, TwinSys), with similar design, but different coating, were implanted. Patients were evaluated clinically and radiologically at 4 weeks, 3 months, 1 year, and annually thereafter.

RESULTS

After a mean follow-up of 46.4 months, the total incidence of revision for aseptic loosening was 0.44% (n = 8). All loose stems were Quadra-S, failing to achieve osseointegration, for an overall incidence of 0.96% (p = 0.002). None of the other stems were loose. Radiolucent lines around the proximal stem portion were visible in 75 Quadra-S stems (4.1%) on radiographs taken at 1 year postoperatively and continued to deteriorate at the latest follow-up.

CONCLUSIONS

In this specific cohort of patients, the increased rate of femoral stem aseptic loosening was implant-related and was attributed only to a specific type of femoral stem (Quadra-S). No relation to other factors was proven suggesting that the surface characteristics of this femoral stem and the lack of bioactive coating are responsible for the observed early femoral failures. These findings should be confirmed by additional registry work and larger population sample sizes are needed to evaluate the prosthesis performance after implantation through the DAA.

The Effect of Surgical Approach and Femoral Prosthesis Type on Revision Rates Following Total Hip Arthroplasty: An Analysis of the Most Commonly Utilized Cementless Stems

BACKGROUND

Compared with other total hip arthroplasty (THA) approaches, the anterior approach has an increased rate of revision for femoral-sided complications, and certain stems may increase this risk. The present study aimed to assess the outcome of THA by surgical approach, according to the femoral stem utilized in the procedure.

METHODS

Data from the Australian Orthopaedic Association National Joint Replacement Registry were analyzed for patients undergoing primary THA for osteoarthritis via the anterior or posterior approach with use of 1 of 5 of the most common cementless femoral stems from January 2015 to December 2019. The primary outcome measures were the cumulative percent revision (CPR) for all causes and for femoral stem loosening and fracture. The CPR was compared between THAs performed via the anterior and posterior approaches for all stems and for each individual femoral stem, as well as between individual femoral stems for each approach.

RESULTS

The study included 48,716 THAs performed with use of cementless stems, of which 22,840 utilized an anterior approach and 25,876 utilized a posterior approach. There was no difference in the all-cause CPR between the anterior and the posterior approach, but the anterior approach had a higher CPR for loosening (hazard ratio [HR], 2.00; 95% confidence interval [CI], 1.48 to 2.69; p < 0.001) and fracture (HR, 1.78; 95% CI, 1.34 to 2.35; p < 0.001). There was apparent variation in the CPR across the different cementless stems when an anterior approach was utilized. The Quadra-H (Medacta) had a higher all-cause CPR when compared with the Polarstem (Smith & Nephew; HR, 1.49; 95% CI, 1.16 to 1.91; p = 0.002) and Corail (DePuy Synthes; HR, 1.31; 95% CI, 1.00 to 1.70; p = 0.0478). Variation was less apparent with the posterior approach.

CONCLUSIONS

THAs performed via the anterior approach had higher rates of revision for femoral stem loosening and fracture, with greater variation in outcomes between individual stems.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Reduction of Periprosthetic Proximal Femur Fracture in Direct Anterior Total Hip According to Stem Design

The direct anterior approach (DAA) is gaining popularity in primary total hip arthroplasty (THA). Although DAA has demonstrated many advantages over other surgical approaches, periprosthetic femur fractures (PPFF) rates continue to be higher. Femoral stem designs that allow for easier insertion via a DAA may contribute to the higher rates of fracture seen in this approach. Certain stem designs and fixation methods may reduce the risk of PPFF via a DAA in primary THA.

Intraoperative Complications and Early Return to the Operating Room in Total Hip Arthroplasty Performed Through the Direct Anterior and Posterior Approaches. An Institutional Experience of Surgeons After Their Learning Curve

BACKGROUND

Proponents of the direct anterior approach (DAA) for total hip arthroplasty (THA) claim a faster recovery, whereas critics claim an increased risk of early femoral complications. This study analyzed intraoperative and postoperative complications requiring reoperation within one year after THA through the DAA and posterior approach (PA).

METHODS

A total of 2348 elective, unilateral DAA THAs in patients with osteoarthritis performed between 2016 and 2019 were matched 1:1 for age (±5 years), gender, body mass index (±5), and femoral fixation with 2348 patients who underwent PA THA during the same period. Mixed-effects logistic regression was used. Odds ratios were reported for the occurrence of intraoperative femoral fracture, postoperative femoral fracture, infection, dislocation, and other etiologies requiring reoperation within one year.

RESULTS

Intraoperative femoral fracture occurred in 12 DAA (0.5%) and 14 PA (0.6%) patients. Twenty-five patients (1.06%) in the DAA and 28 (1.19%) in the PA group underwent reoperation within the first year. Reoperations were due to periprosthetic fracture (40%), infection (28%), dislocation (23%), and other (9%). Regression analysis revealed no difference in intraoperative femoral fracture (odds ratio (OR): 0.86, 95% confidence interval (CI): 0.40-1.86, P = .69), postoperative femoral fracture (OR: 1.10, 95% CI: 0.47-2.60, P = .83), infection (OR: 1.50, 95% CI: 0.53-5.23, P = .44), or reoperation within one year for other reasons (OR: 1.50, 95% CI: 0.25-9.00, P = .65). DAA had fewer dislocations requiring reoperation (OR: 0.20, 95% CI: 0.04-0.91, P = .02).

CONCLUSION

This comparative study did not find differences in intraoperative or postoperative fracture or infection between DAA and PA. DAA was associated with a lower likelihood of reoperation for dislocation within one year of surgery.

Complex Primary Total Hip Arthroplasty: Small Stems for Big Challenges

Total hip arthroplasty is one of the most successful operations in all of medicine. Femoral deformities from malunion, prior osteotomy, and retained surgical implants all present unique challenges. Corrective osteotomy and hardware removal add significant morbidity to an operation that typically has a fast recovery. Short stems can be used in these cases to spare patients' increased morbidity. We present a case-based illustration and surgical technique for the use of short stems in complex primary total hip arthroplasty with femoral deformity and retained hardware. We discuss how these implants can spare significant morbidity, show radiographic examples of their use, and present short-term outcomes.

Short stem total hip arthroplasty with the direct anterior approach demonstrates suboptimal fixation

PURPOSE

Short stems use has increased substantially despite variable results reported in the literature. The purpose of this study was to report the rate of complications using a short stem implanted through the direct anterior approach (DAA), and to evaluate mid-term clinical and radiological results focusing on femoral stem fixation.

METHODS

Between April 2009 and November 2014, 698 elective total hip arthroplasties (THAs) were performed using a fully hydroxyapatite-coated short stem (AMIStem-H®). The mean age was 65.7 years (SD 12.6). Patients were invited for clinical and radiological evaluation, and to complete patient-reported outcomes questionnaires at two and five years after surgery. The mean follow-up was 6.2 years (range 2-9.73 years).

RESULTS

During the study period, 59 (8.5%) patients died and 24 (3.4%) were lost to follow-up. There were six (0.9%) dislocations and 12 (1.7%) fractures, seven occurred intra-operatively. Twenty-nine (4.2%) THAs required revision surgery. Eleven THAs were revised for aseptic loosening of the stem at a mean 4.9 years (1.2-7.3 years). Five years after surgery, radiographs of 324 THAs (324/425 eligible = 76.2%) were available. Stem subsidence ≥ 2 mm was present in 42 cases (12.9%), proximal radiolucencies in 101 hips (31.5%), cortical thickening in 52 (16.0%), and a pedestal in 219 (67.6%). An Engh score between - 10 and 0 was associated with lower HHS pain subscore (p = 0.005), a higher risk of stem revision for aseptic loosening (18.8% vs. 2.7%; p = 0.008), and was more frequent in younger patients with ASA score 1.

CONCLUSION

Patients presenting radiological alterations at five years had an increased risk of revision for aseptic stem loosening and also inferior clinical results. Our study warrants further continued scrutiny of mid- and long-term survivorship of the AMIStem-H®, with radiological results at five years indicating suboptimal fixation of the stem in younger and active patients.

Factors affecting the incidence of postoperative periprosthetic fractures following primary and revision hip arthroplasty: a systematic review and meta-analysis

Objectives

The increasing number of hip arthroplasties (HA), due to the growing elderly population, is associated with the risk of femoral periprosthetic fractures (FPFs). The purpose of this study was to identify potential risk factors for the development of FPFs after HA.

Methods

A systematic review was conducted in five data bases (Medline, Embase, Cochrane, Cinahl, ICTRP) according to the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) guidelines up to May 2019, using the key words “risk factor,” “periprosthetic fracture,” and “hip replacement or arthroplasty.” Meta-analysis of the clinical outcomes of HA and subgroup analysis based on the factors that were implicated in FPFs was performed.

Results

Sixteen studies were included (sample size: 599,551 HA patients, 4253 FPFs, incidence 0.71%). Risk factors statistically associated with increased incidence of FPFs were female gender (+ 40%), previous revision arthroplasty surgery (× 3 times), and the presence of rheumatoid arthritis (× 2.1 times), while osteoarthritis (− 57%), cement application (− 59%), and insertion of Biomet (− 68%) or Thompson’s prosthesis (− 75%) were correlated with low prevalence of FPFs. Obesity, cardiac diseases, advanced age, bad general health (ASA grade ≥ 3), and use of Exeter or Lubinus prosthesis were not linked to the appearance of FPFs.

Conclusion

This meta-analysis suggested that female gender, rheumatoid arthritis, and revision arthroplasty are major risk factors for the development of FPFs after a HA. In those patients, frequent follow-ups should be planned. Further prospective studies are necessary to clarify all the risk factors contributing to the appearance of FPFs after HA.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13018-020-02152-0.

4- to 8-year complication analysis of 2 'partial collum' femoral stems in primary THA

OBJECTIVES

Compare the clinical and radiological outcome of CFP stem with the MiniHip design in a prospective series, with special interest in intraoperative periprosthetic fracture (IPPF).

METHODS

We prospectively followed 101 cases treated with the MiniHip stem (Group 1) and 89 with the CFP stem (Group 2) operated between 2010 and 2014. No significant demographic differences were observed between both groups. Median follow-up was 72 months. Average stem length was 41% shorter in the MiniHip group (p < 0.001). Radiological parameters were measured and a logistcic regression model was created to evaluate factors associated with IPPF.

RESULTS

Mean mHHS improved from 54 to 95 in the MiniHip group (p < 0.001) and from 64 to 98 in the CFP group (p < 0.001). No significant differences were observed in terms of loosening, infection or instability. We observed 7 IPPFs (3.68%), 3 in group 1 and 4 in group 2. After adjusting for confounders, CFP was not associated with a greater risk of IPPF (OR 3.23; 95% CI, 0.250-42.034, p = 0.368), however, a more complex fracture pattern was observed with this stem design. Prior acetabular fractures were associated with IPPF (OR 66.85; 95% CI, 1.142-3911, p = 0.043). Compared to Dorr A femurs, type Dorr B appeared protective against IPPF (OR 0.039; 95% CI, 0.001-1.109, p = 0.058). Valgus alignment tended to increase the risk of IPPF (OR 20.59; 95% CI 0.870-487.221, p = 0.061).

CONCLUSIONS

MiniHip showed similar radiological outcomes to CFP at short- to mid-term follow-up without increasing IPPFs with a shorter stem length. Given that CFP produced a more complex IPPF pattern, surgeons should be cautious with alignment of this particular design, especially in Dorr A femur.

Atypical periprosthetic femoral fracture associated with long-term bisphosphonate therapy

Background

Atypical femoral fracture is one of the many complications after the long-term use of bisphosphonates. The American Society for Bone and Mineral Research has officially excluded periprosthetic femoral fractures (PFFs) from the definition of atypical femoral fractures (AFFs). Several case reports found that PFFs can occur with characteristics similar to those of AFFs. The purpose of our study was to evaluate the proportion of atypical fractures among Vancouver type B1 fractures, and to determine the association between the long-term use of bisphosphonates and the occurrence of atypical periprosthetic femoral fractures (APFFs).

Methods

In this retrospective study, we reviewed 41 patients with Vancouver type B1 periprosthetic fractures between January 1, 2011 and December 31, 2018. We classified them into two groups, namely atypical and typical PFFs, based on the fracture morphology. We noted the proportion of atypical periprosthetic fractures among B1 fractures and identified risk factors.

Results

Among the 41 PFFs, 5 (13%) fractures were classified as atypical PFF based on the radiological characteristics. The longer duration of bisphosphonate use was probably the only independent risk factor that significantly increases the occurrence of APFF (p = 0.03, 0.08 (CI 0.008 – 0.16)). There were no significant differences in age, gender, body mass index, comorbidities, corticosteroid use, positioning of the femoral stem, the method of fixation (cemented or cementless) and time lapse from before the primary prosthesis implantation to the PFF in the development of atypical fracture type.

Conclusions

There seems to be a correlation between the long-term intake of bisphosphonates and the atypical periprosthetic fracture. Atypical femoral fracture can also occur in the periprosthetic form.

Trial registration

Study number: 22/2019-SZTE, http://www.klinikaikutatas.hu/hu/kutatasetika/jovahagyott-vizsgalatok-koezerdeku-adatai/category/25-jovahagyott-vizsgalatok-kozerdeku-adatai-rkeb-2019.html?download=985:22-2019.

Predictors of Perioperative Vancouver B Periprosthetic Femoral Fractures Associated With the Direct Anterior Approach to Total Hip Arthroplasty

BACKGROUND

There is an association between intraoperative and postoperative femoral fractures and the direct anterior approach (DAA) to total hip arthroplasty (THA). The purpose of our study is to identify risk factors for Vancouver B fractures and to establish a predictable timeline for when these occur.

METHODS

We retrospectively identified patients with Vancouver B periprosthetic femoral fractures (n = 49) after 11,509 elective primary cementless THA procedures through the DAA between 2012 and 2018 at a single institution. Fracture patients were matched to nonfracture patients (n = 267) by date of surgery and surgeon. Clinical and radiographic factors were collected for multivariable analysis to identify predictors of fracture.

RESULTS

Periprosthetic Vancouver B femoral fracture incidence was 0.4%. 48 (98%) fractures were postoperative. Fractures occurred at an average of 44 days after surgery (range: 1 to 653 days) with >85% of fractures occurring in the first 6 weeks postoperatively. Significant variables predictive of fracture included >3 degrees valgus and >5 degrees varus coronal stem malalignment, Dorr B and C femoral geometry, lower canal flare index (2.75 vs 3.20), advanced age, increased comorbidities, greater stem canal fill, and right-sided procedures.

CONCLUSION

Despite an overall low rate of Vancouver B perioperative periprosthetic femoral fractures, it is a devastating complication that typically presents within the first 6 weeks after DAA THA surgery. The risk is increased in patients with unfavorable proximal femoral geometry, coronal stem malalignment, advanced age, increased comorbidities, and right-sided procedures.

Calcar-Guided Short Stems in Total Hip Arthroplasty: A Two-Year Prospective Multicentre Study

Background:

Calcar-guided short-stem Total Hip Arthroplasty (THA) is increasingly being used to preserve proximal femoral bone stock for potential later revision surgery.

Objective:

In this study, we aimed to expand the clinical evidence on calcar-guided short-stem THA used in daily clinical practice, focusing on clinical outcomes as well as radiographic signs of stress shielding and femoral bone loss.

Methods:

In a prospective multicentre study, we enrolled 213 patients with a total of 224 THAs for mainly degenerative indications. The patients were examined clinically and radiographically 6 to 12 weeks, 12 months, and 24 months postoperatively.

Results:

All clinical outcomes improved significantly over the first 6 to 12 weeks compared to preoperative values (P < 0.001). At 24 months, the mean Harris hip score was 95.3 ± 6.7, and the mean visual analogue scale for pain was 1.0 ± 1.7 under load and 0.5 ± 1.3 at rest. We observed early distal stem migration in six patients and late migration in one patient. Additionally, we found 16 cases of radiographic signs indicative of stress shielding. Four patients required stem revision surgery: two for stem migration, one for periprosthetic fracture, and one for deep infection.

Conclusion:

Overall, calcar-guided short-stem THA resulted in excellent clinical outcomes after two years of follow-up, and the radiographs revealed few signs of stress shielding. We, therefore, regard calcar-guided short-stem THA as a safe and effective treatment alternative in daily clinical practice.

Risk Factors for Periprosthetic Femur Fracture and Influence of Femoral Fixation Using the Mini-Anterolateral Approach in Primary Total Hip Arthroplasty

BACKGROUND

The mini-anterolateral (AL) approach for total hip arthroplasty (THA) has gained popularity. In contrast to other approaches, risk factors for periprosthetic femur fractures have not been well established for the AL approach.

METHODS

Six hundred eighty-four primary THAs performed using the AL approach were retrospectively reviewed for risk factors associated with perioperative periprosthetic femur fractures within 3 months of surgery. Risk factors evaluated were gender, age, body mass index, laterality, and Dorr ratio of the proximal femur. Cemented stems and collared uncemented stems were compared to uncemented tapered-wedge and meta-diaphyseal stems. A Student's t-test was used for continuous variables, and a chi-squared test was used for categorical variables.

RESULTS

Of 684 primary THAs performed, 57 (8.3%) resulted in fracture. Twenty-eight (4.1%) occurred intraoperatively and 29 (4.2%) occurred postoperatively within 90 days. All intraoperative fractures were fixed at the time of surgery and healed uneventfully. Of the postoperative fractures, 15 (2.2%) were amenable to nonoperative management and healed. Fourteen (2.0%) required revision arthroplasty. There was a significantly lower rate of fracture in patients receiving cemented or collared stems (0%, n = 101) than in those receiving tapered-wedge or meta-diaphyseal fitting stems (9.8%, n = 583; P = .0009). Odds of fracture increased with female gender (P = .0063) and increasing Dorr ratio (P = .0003). Analysis showed a trend toward increased risk with older age, but did not achieve statistical significance. Body mass index and laterality showed no statistically significant effect.

CONCLUSION

Performing primary THA via the AL approach, 2.0% of patients had a postoperative fracture requiring revision within the first 3 months. With cemented and collared stems, the fracture rate was significantly lower. Surgeons should consider using cemented or collared stems in high-risk patients.

Short stems have lower load at failure than double-wedged stems in a cadaveric cementless fracture model

Objectives

Periprosthetic femoral fractures (PFFs) have a higher incidence with cementless stems. The highest incidence among various cementless stem types was observed with double-wedged stems. Short stems have been introduced as a bone-preserving alternative with a higher incidence of PFF in some studies. The purpose of this study was a direct load-to-failure comparison of a double-wedged cementless stem and a short cementless stem in a cadaveric fracture model.

Methods

Eight hips from four human cadaveric specimens (age mean 76 years (60 to 89)) and eight fourth-generation composite femurs were used. None of the cadaveric specimens had compromised quality (mean T value 0.4 (-1.0 to 5.7)). Each specimen from a pair randomly received either a double-wedged stem or a short stem. A materials testing machine was used for lateral load-to-failure test of up to a maximal load of 5000 N.

Results

Mean load at failure of the double-wedged stem was 2540 N (1845 to 2995) and 1867 N (1135 to 2345) for the short stem (p < 0.001). All specimens showed the same fracture pattern, consistent with a Vancouver B2 fracture. The double-wedged stem was able to sustain a higher load than its short-stemmed counterpart in all cases. Failure force was not correlated to the bone mineral density (p = 0.718).

Conclusion

Short stems have a significantly lower primary load at failure compared with double-wedged stems in both cadaveric and composite specimens. Surgeons should consider this biomechanical property when deciding on the use of short femoral stem.

Cite this article: A. Klasan, M. Bäumlein, P. Dworschak, C. Bliemel, T. Neri, M. D. Schofer, T. J. Heyse. Short stems have lower load at failure than double-wedged stems in a cadaveric cementless fracture model. Bone Joint Res 2019;8:489–494. DOI: 10.1302/2046-3758.810.BJR-2019-0051.R1.

Preferred Single-Vendor Program for Total Joint Arthroplasty Implants: Surgeon Adoption, Outcomes, and Cost Savings

BACKGROUND

In total joint arthroplasty, variation in implant use can be driven by vendor relationships, surgeon preference, and technological advancements. Our institution developed a preferred single-vendor program for primary hip and knee arthroplasty. We hypothesized that this initiative would decrease implant costs without compromising performance on quality metrics.

METHODS

The utilization of implants from the preferred vendor was evaluated for the first 12 months of the contract (September 1, 2017, to August 31, 2018; n = 4,246 cases) compared with the prior year (September 1, 2016, to August 31, 2017; n = 3,586 cases). Per-case implant costs were compared using means and independent-samples t tests. Performance on quality metrics, including 30-day readmission, 30-day surgical site infection (SSI), and length of stay (LOS), was compared using multivariable-adjusted regression models.

RESULTS

The utilization of implants from the preferred vendor increased from 50% to 69% (p < 0.001), with greater use of knee implants than hip implants from the preferred vendor, although significant growth was seen for both (from 62% to 81% for knee, p < 0.001; and from 38% to 58% for hip, p < 0.001). Adoption of the preferred-vendor initiative was greatest among low-volume surgeons (from 22% to 87%; p < 0.001) and lowest among very high-volume surgeons (from 61% to 62%; p = 0.573). For cases in which implants from the preferred vendor were utilized, the mean cost per case decreased by 23% in the program's first year (p < 0.001), with an associated 11% decrease in the standard deviation. Among all cases, there were no significant changes with respect to 30-day readmission (p = 0.449) or SSI (p = 0.059), while mean LOS decreased in the program's first year (p < 0.001).

CONCLUSIONS

The creation of a preferred single-vendor model for hip and knee arthroplasty implants led to significant cost savings and decreased cost variability within the program's first year. Higher-volume surgeons were less likely to modify their implant choice than were lower-volume surgeons. Despite the potential learning curve associated with changes in surgical implants, there was no difference in short-term quality metrics.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Comparative outcomes between collared versus collarless and short versus long stem of direct anterior approach total hip arthroplasty: a systematic review and indirect meta-analysis

INTRODUCTION

Early research shows several advantages of the direct anterior approach (DAA) in THA that claimed to be as effective but less invasive than the posterior approach. However, due to the difficult femoral exposure and possible complications related to femoral preparation, this approach may result in a higher rate of undersized stems when compared to other approaches. The present authors believe that the femoral implant design (collar or collarless stem, short or long stem) in a collared femoral stem may relate to lower rates of stem subsidence and limb length discrepancy (LLD) in mid-term to long-term follow-up when compared to collarless femoral stems. However, currently, there is no consensus as to which femoral implant design is the most suitable for DAA in THA.

METHODS

This systematic review and meta-analysis aim to assess and compare postoperative complications (neurapraxia, wound infection, LFCN, hematoma, artery injury, cup malposition, embolism, fracture and implant loosening) and revision rates due to dislocation, periprosthetic fracture and implant migration after DAA using collared compared to collarless femoral stem and short femoral stem compared to long femoral stem in THA. These clinical outcomes consist of the postoperative complications and revision femoral stem due to neurapraxia, wound, LFCN and LLD. This systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

RESULTS

Relevant studies that reported postoperative complications and revision of either implant were identified from Medline and Scopus from inception to June 6, 2018. Thirty-four studies were included for the analysis of DAA in THA; 23 studies were retrospective cohorts, four studies were prospective cohorts, and seven studies were RCTs. Thirty-one studies and three studies were included for analysis of collarless and collared femoral stems. Twenty-six studies were long femoral stems and eight studies were short femoral stems. Overall, there were 6825 patients (6457 in the collarless group and 368 in the collared group, 4280 in long stem and 2545 in short stem). A total of 469 and 66 patients had complications and revisions in the collarless group, and no patient had complications and revisions in the collared stem group. The total complication and revision rate per patient were 5% (95%CI 3.3%, 7%) and 0.9% (95%CI 0.6%, 1.2%) in all patients. The complication rate and revision rate were 5.7% (95%CI 3.8%, 7.7%) and 0.9% (95%CI 0.6, 1.2) in the collarless group. There was no prevalence of complications and revisions in the collared stem group. The complication rate and revision rate were 10.2% (95%CI 9%, 11.4%), 0.7% (95%CI 0.3%, 1%) and 5.2% (95%CI 3.1, 7.2), 1.5% (95%CI 1%, 2%) in short and long femoral stems, respectively. Indirect meta-analysis shows that collared femoral stem provided a lower risk of complications of 0.02 (95%CI 0.001, 0.30) when compared to collarless femoral stem. Long femoral stems had a lower risk of having complications of 0.57 (95%CI 0.48, 0.68) when compared to short femoral stems. In terms of revision, there is no statistically significant difference in collared femoral stem compared to collarless femoral stem and long femoral stem compared to short femoral stem.

CONCLUSION

In DAA THA, collared femoral stem and long femoral stem had decreased complication rates when compared to collarless femoral stem and short femoral stem by both direct and indirect meta-analysis methods. However, in terms of revision rates, there were no differences between all femoral stems (short versus long and collared versus collarless). Prospective randomized controlled studies are needed to confirm these findings as the current literature is still insufficient.

Cementless short-stem total hip arthroplasty in the elderly patient - is it a safe option?: a prospective multicentre observational study

Background

Due to its bone preserving philosophy, short-stem total hip arthroplasty (THA) has primarily been recommended for young and active patients. However, there may be benefits for elderly patients given a less invasive operative technique due to the short curved implant design. The purpose of this study was to compare the clinical and radiological outcomes as well as perioperative complications of a calcar-guided short stem between a young (< 60 years) and a geriatric (> 75 years) population.

Methods

Data were collected in a total of 5 centers, and 400 short-stems were included as part of a prospective multicentre observational study between 2010 and 2014 with a mean follow-up of 49.2 months. Preoperative femur morphology was analysed using the Dorr classification. Clinical and radiological outcomes were assessed in both groups as well as perioperative complications, rates and reasons for stem revision.

Results

No differences were found for the mean visual analogue scale (VAS) values of rest pain, load pain, and satisfaction, whereas Harris Hip Score (HHS) was slightly better in the young group. Comparing both groups, none of the radiological parameters that were assessed (stress-shielding, cortical hypertrophy, radiolucency, osteolysis) reached differences of statistical significance. While in young patients aseptic loosening is the main cause of implant failure, in the elderly group particularly postoperative periprosthetic fractures due to accidental fall have to be considered to be of high risk. The incidence of periprosthetic fractures was found to be 0% in Dorr type A femurs, whereas in Dorr types B and C fractures occurred in 2.1 and 22.2% respectively.

Conclusions

Advanced age alone is not necessarily to be considered as contra-indications for calcar-guided short-stem THA, although further follow-up is needed. However, markedly reduced bone quality with femur morphology of Dorr type C seems to be associated with increased risk for postoperative periprosthetic fractures, thus indication should be limited to Dorr types A and B.

Trial registration

German Clinical Trials Register; DRKS00012634, 07.07.2017 (retrospectively registered).

Direct Anterior Approach Total Hip Arthroplasty Using a Morphometrically Optimized Femoral Stem, a Conventional Operating Table, Without Fluoroscopy

BACKGROUND

Our experience with direct anterior approach total hip arthroplasty (THA) suggests that it can be performed successfully with a morphometrically optimized metaphyseal-diaphyseal engaging femoral stem (NOT a short stem), a regular operating room table (NOT a special custom table), and WITHOUT intraoperative fluoroscopy. We report our minimum 2-year results.

METHODS

A retrospective review of a single-surgeon series of primary direct anterior approach THAs was performed. All procedures were performed on a regular table, without fluoroscopy, using a cementless tapered femoral stem. Clinical, functional, and radiographic outcomes were evaluated at a minimum of 2 years.

RESULTS

In total, 1017 primary THAs were performed. The preoperative Harris Hip Score was 40.7 ± 5.1 and improved to 95.3 ± 4.2 at minimum 2-year follow-up. There were 3 dislocations (0.3%) and 15 revisions (1.5%): 7 for infection (0.7%), 4 for periprosthetic fractures (0.4%), 2 for instability (0.2%), 1 for loosening (0.1%), and 1 for pain (0.1%). Five patients (0.5%) required blood transfusion. One patient developed deep vein thrombosis and pulmonary embolism. No intraoperative fractures, perforation, or THA-related mortality occurred. Neutral stem alignment was confirmed in 98.3%. Mean cup inclination was 38.8° ± 5.1° and anteversion was 16.2° ± 3.5°. The mean leg-length discrepancy was corrected from 1.2 ± 0.2 cm preoperatively to 0.2 ± 0.1 cm postoperatively.

CONCLUSION

Using a morphometrically optimized metaphyseal-diaphyseal engaging tapered femoral stem instead of a short stem reduces component malposition and minimizes risk of loosening. Combining the use of this implant design and the technique and elements described in our cohort demonstrated to have excellent results at 2 years. The patients will need continued follow-up to demonstrate further durability of this device and technique compared to others performing direct anterior THA.

Early perioperative complication rates and subsidence with the Tribute® short cementless, tapered stem in primary total hip arthroplasty

This study examined early perioperative complications and subsidence following total hip arthroplasty (THA) with a short femoral stem. A retrospective review of 207 consecutive patients (247 hips) having undergone THA via the direct anterior approach produced only six perioperative complications: two intraoperative fractures, three perioperative femur fractures and one dislocation. Subsidence greater than 5 mm was observed in four hips but subsidence did not progress greater than 3 mm at the latest follow-up. Based on these results, cementless THA though the direct anterior approach with a short femoral stem provides a clinical and radiographic advantage while maintaining low complication rates.

Direct Anterior Approach and Perioperative Fracture With a Single-Taper Wedge Femoral Component

BACKGROUND

Despite growing interest in direct anterior approach total hip arthroplasty, perioperative femoral fracture and early aseptic loosening are increasingly recognized complications. Previous research has documented the role of surgeon experience in association with these femoral complications. The purpose of this study was to explore the relationship between femoral component design and early periprosthetic femoral complications.

METHODS

This was an extension of previous work with an updated patient cohort of 5090 consecutive direct anterior primary total hip arthroplasties at a single institution with a single-taper, wedge femoral stem comprising 4 variants involving length and geometry: group 1, full-length, standard profile; group 2, full-length, reduced distal profile; group 3, short-length, standard profile; and group 4, short-length, reduced distal profile. Records were reviewed retrospectively for the incidence of early postoperative periprosthetic fracture or aseptic loosening and analyzed with regard to patient demographics and femoral stem type.

RESULTS

There were 42 (0.83%) periprosthetic femur complications observed in the early postoperative period. Increased age (P < .001) and female gender (P = .023) were significantly associated with incidence of femoral complications in univariate analysis, while age maintained this significant relationship in multivariate analysis (P < .001). There was a trend toward increased complication rate in patients receiving a short stem with full profile taper (1.27%, P = .0539).

CONCLUSION

Despite an overall low rate of femoral complications after direct anterior total hip arthroplasty, the risk is increased in elderly patients and females. Furthermore, femoral stem design may portend an elevated risk of these complications.

Total hip arthroplasty through an anterior approach: The pros and cons

Total hip arthroplasty through an anterior approach has been increasing in popularity amongst surgeons and patients.

Anterior approach hip arthroplasty seems to offer improved early outcomes in terms of pain, rehabilitation and length of stay.

No difference in long-term outcomes has been shown between anterior and posterior or lateral approaches.

Proper formal training, utilization of fluoroscopy and adequate experience can mitigate risks of complications and improve early and medium-term outcomes.

Cite this article: EFORT Open Rev 2018;3:574-583. DOI: 10.1302/2058-5241.3.180023.

Direct Anterior Approach Total Hip Arthroplasty: An Adjunct to an Enhanced Recovery Pathway: Outcomes and Learning Curve Effects in Surgeons Transitioning From Other Surgical Approaches

BACKGROUND

The aim of this study was to investigate whether the direct anterior approach (DAA) to total hip arthroplasty (THA) resulted in a shorter length of stay (LOS) in surgeons new to the approach when compared to their previously used approach. Perioperative complications were also assessed.

METHODS

We examined 93 DAA THA performed by 3 hip arthroplasty surgeons at a single institution comparing these to their previous 166 operations performed using the lateral or posterior approach.

RESULTS

Fixed-effects generalized linear modeling demonstrated that patients who underwent THA by the DAA had 26% shorter LOS than those who were operated on using lateral or posterior approaches (adjusted risk ratio = 0.74; 95% confidence interval = 0.65-0.84; P < .001). A greater proportion of DAA patients were discharged directly home (98% vs 87%, F (1,233) = 8.12, P = .005) and complication rates were comparable between groups.

CONCLUSION

The DAA can reduce patient LOS and may be a valuable addition to enhanced recovery pathways. Our findings also suggest that surgeons transitioning to the DAA do not have an increased complication rate when compared to their previous approach.