A Distal Fluted,Proximal Modular Femoral Prosthesis in Revision Hip Arthroplasty

Most reports on the use of modular femoral stems during revision surgery have involved short follow-up periods. The authors evaluated the clinical and radiographic performance of 59 patients fitted with a distal fix modular stem. The average follow-up period was 8.2 years. Average Harris hip score was improved from 47 to 87.6. Of 19 patients with trochanteric osteotomy, 4 had a displaced greater trochanter. Re-revision was performed in 5 patients, and 3 of these were for subsidence (of these 3, subsidence was associated with dissociation of the coupling part in 1 and with osteotomy nonunion in other 2 [proximal component only]). Modular distally fixed femoral stems were found to offer intraoperative flexibility, but to suffer from subsidence and intraoperative greater trochanter and metaphyseal femoral fractures.     

Revision Total Hip Arthroplasty With a Modular Cementless Femoral Stem

We retrospectively reviewed 123 patients who underwent cementless THA with modular femoral stem designs for revision THA or conversion of failed ORIF and found 75 patients available for analysis. The Harris Hip Score (HHS) improved from 52 ± 14 to 86 ± 11 (P < 0.001). The femoral stem was re-revised in eight patients (11%). The mean time to re-revision was 1.1 years (0.13–2.54). Reasons for re-revision included infection (n = 5, 7%), aseptic loosening (n = 2, 3%) and significant pain (n = 1, 1%). There were no failures of the modular junctions. PC stems had an increased rate of intraoperative fractures (PC 28% vs. STS 9%, P = 0.04). Modular cementless femoral stems provide acceptable mid-term results in revision THA.     

Seven-year Results of a Tapered, Titanium, Hydroxyapatite-Coated Cementless Femoral Stem in Primary Total Hip Arthroplasty

Background

Aseptic loosening of cemented hip prostheses is recognized as a long-term problem, and especially in males and younger patients. Much energy has been focused on developing new prostheses that are designed for cementless fixation. We evaluated the performance of and periprosthetic bone response to a tapered, titanium, hydroxyapatite (HA)-coated femoral hip prosthesis at a minimum of 7 years of follow-up after treatment with primary total hip arthroplasty.

Methods

Seventy-eight patients and 86 hips were included in the study. There were 35 men and 43 women; the mean age at the time of the operation was 59 years (range, 41 to 81 years). We used a tapered, titanium (Ti6Al4V), HA-coated femoral implant. We evaluated the patients at a minimum of 7 years of follow-up after treatment with primary total hip arthroplasty. Clinical evaluation was performed using the scoring system and the hip scores were assigned according to the level of pain, the functional status and the range of motion. The patients who refused to return, but who did forward X-rays for review after being contacted were questioned by phone about the functional status of their hip. Radiographic follow-up was performed at six weeks, at three, six and twelve months and yearly thereafter. All the available radiographs were collected and assessed for implant stability, subsidence, osseointegration, osteolysis, stress shielding and evidence of periprosthetic lucency.

Results

Eighty-six hips (78 patients) were available for review at follow-up of greater than 7 years. In 11 of the 86 cases, acetabular failure required revision of the acetabular component, but the femoral stem survived and it was available for long-term evaluation. The radiographs were obtained at 7-year follow-up for another 20 hips, but the patients would not come in for the 7-year clinical evaluation. Therefore, a phone interview was conducted to assess any change in the functional status at a minimum of 7 years.

Conclusions

The mechanical fixation of a tapered, titanium, HA-coated femoral implant was excellent in this study. This femoral design provided reliable osseointegration that was durable at a mean of 7 years follow-up.     

Femoral Stem Survivorship in Dorr Type A Femurs After Total Hip Arthroplasty Using a Cementless Tapered Wedge Stem: A Matched Comparative Study With Type B Femurs

Background

There is a lack of understanding on relationship between the femoral geometry and outcomes of total hip arthroplasty (THA). We investigated clinical and radiographic outcomes of THA using a cementless tapered wedge stem in patients with Dorr type A proximal femoral morphology and compared with those of type B femurs at a minimum follow-up of 5 years.

The Relationship Between Canal Diameter and the Dorr Classification

BackgroundParticularly in broach-only uncemented total hip arthroplasty, a narrow femoral canal presents a technical challenge. Traditionally such femurs have been considered to be Dorr A. To our knowledge, however, no study has reported on the relationship between isthmus width and the Dorr classification.MethodsWe reviewed 500 high-quality, hard copy radiographs. Dorr classification and isthmus canal width were measured using an electronic caliper by 5 independent observers with intraobserver and interobserver error calculated. For this study, we defined a narrow canal as being ≤10 mm at its narrowest point (isthmus).ResultsEight percent (40) were Dorr A, 85% (424) Dorr B, and 7% (36) Dorr C. With respect to isthmus width for Dorr A, 63% (25) were ≤10 mm compared to just 13% (55) of Dorr B. However, overall because there were more Dorr B femurs, 69% of those with an isthmus of ≤10 mm were Dorr B.ConclusionIn this population, almost 70% of patients with an isthmus ≤10 mm were Dorr B, with only 30% being Dorr A. When using a broach-only technique, isthmus width should be routinely measured on the preoperative anteroposterior radiographs so as to alert the surgeon to potential problems.     

Femoral Revision with an Extensively Hydroxyapatite-Coated Femoral Component

Between December 1996 and April 2003, 26 consecutive femoral component revisions in 24 patients were performed with an extensively hydroxyapatite-coated femoral stem. Two patients were lost to follow-up, and two patients died of unrelated causes. Of the 22 femoral revisions in 20 patients, there was a 0% incidence of mechanical loosening at average follow-up of 3.2 years (2–6.3 years). The Harris Hip Score improved from 59 (36 to 83) to 95 (84 to 100) postoperatively (p < 0.001). Rate of revision was 18.2% (4.5% for sepsis, 9.1% for instability, and 4.5% for polyethelene wear). All 22 femoral components had evidence of bone ingrowth. The extensively coated hydroxyapatite stem in this series produced excellent clinical results with a low incidence of thigh pain (4.5%) and severe stress shielding (4.5%).     

Revision Hip Arthroplasty With a Short Femoral Component in Fractured Hydroxyapatite Fully Coated Femoral Stem

We describe a case of a fractured femoral component in a hydroxyapatite-coated cementless total hip arthroplasty that was revised using a prosthesis with circumferential proximal metaphyseal support and a lateral flare, with a short femoral stem. This type of prosthesis allows for revision, thus, avoiding the removal of the distal part of the previous prosthesis well bonded to the bone. This makes the revision arthroplasty easier and the patient's recovery quicker.     

Periprosthetic Femoral Fractures in Cementless Short Versus Straight Stem Total Hip Arthroplasty: A Propensity Score Matched Analysis

BackgroundRecent studies indicate a decreased risk of periprosthetic femoral fractures (PFFs) in cementless total hip arthroplasty (THA) for short compared to straight stems. However, the results are still inconclusive. Therefore, we retrospectively investigated the rate of PFFs within the first year between cementless short and straight stem THA.MethodsA 1:1 propensity score matching of 3,053 THAs was performed. Two groups including 1,147 short stem THAs implanted through a minimally invasive antero-lateral approach and 1,147 straight stem THAs implanted through a transgluteal Hardinge approach were matched. The rates of PFFs and fracture patterns were compared between both stem types. Risk factors for PFFs were analyzed by multivariate regression analyses.ResultsThe overall rate of PFFs was 1.7% in short stem THA and 3.2% in straight stem THA (P = .015). Postoperatively detected Vancouver A fractures occurred significantly more often in straight stem THA (P = .002), while the occurrence Vancouver B fractures did not differ significantly (P = .563). The risk of PFFs was significantly increased for women in straight stem THA (Odds ratio (OR) 2.620; Confidence Interval (CI) 1.172-5.856; P = .019). Increasing age showed a significantly increased odds ratio in short stem (OR 1.103; CI 1.041-1.169, P < .001) and straight stem THA (OR 1.057; CI 1.014-1.101, P = .008).ConclusionShort stem THA reduces Vancouver Type A PFFs in the trochanteric region compared to straight stem THA, while Vancouver Type B fractures are comparable. Increasing age is a significant risk factor for both stem types, while the risk for PFFs in women was only significantly increased in the straight stem group.     

Cumulative Long-Term Incidence of Postoperative Periprosthetic Femoral Fractures Using an Uncemented Tapered Titanium Hip Stem: 26- to 32-Year Results

Background

Although falling is becoming a major problem in the elderly, little is known about the long-term incidence of postoperative periprosthetic femoral fractures (PFF) after total hip arthroplasty (THA) using uncemented stems with a minimum follow-up of 26 years postoperatively.

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem

BackgroundThis study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years.MethodsWe conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael’s Hip Score.ResultsForty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael’s Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening.ConclusionThis triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.     

A Role for Modern Primary Cementless Femoral Stems in Revision Hip Arthroplasty

BackgroundIn revision total hip arthroplasty (THA) cases with preserved femoral metaphyseal bone, tapered proximally porous-coated “primary” femoral stems may be an option. The objective of this study was to compare outcomes of patients with Paprosky I or II femoral bone loss undergoing revision THA with either a primary metaphyseal-engaging cementless stem or a revision diaphyseal-engaging stem.MethodsThis was a retrospective analysis of 70 patients with Paprosky I or II femoral bone loss who underwent femoral revision. 35 patients who were revised using a primary cementless femoral stem were compared with 35 patients who underwent femoral revision using a revision diaphyseal-engaging stem. The groups were similar regarding age, gender, body mass index, and American Society of Anesthesiologists. Clinical and radiographic outcomes and complications were compared over an average follow-up of 2.9 years (SD 1.4).ResultsRevision THA was most commonly performed for periprosthetic joint infection (N = 27, 38.6%). The groups were similar with regards to Paprosky femoral classification (P = .56), length of stay (P = .68), discharge disposition (P = .461), operative time (P = .20), and complications (P = .164). There were no significant differences between primary and revision femoral stem subsidence (0.12 vs. 0.75 mm, P = .18), leg length discrepancy (2.3 vs. 4.05 mm, P = .37), and Hip Disability and Osteoarthritis Outcome Score Jr (73.1 [SD 21.1] vs. 62.8 [SD 21.7], P = .088). No patient underwent additional revision surgery involving the femoral component.ConclusionUse of modern primary cementless femoral stems is a viable option for revision hip arthroplasty in the setting of preserved proximal femoral metaphyseal bone. Outcomes are not inferior to those of revision stems and offer potential benefits.     

Early Post-operative Periprosthetic Femur Fracture in the Presence of a Non-cemented Tapered Wedge Femoral Stem

Non-cemented femoral fixation in hip arthroplasty has become the standard of practice in the USA. However, recent literature has brought attention to an increasing incidence of periprosthetic femur fractures with certain stem designs. This study examines reasons for early periprosthetic femur fractures in patients with a hip arthroplasty performed using a non-cemented tapered wedge stem design. A multivariate analysis using a matched-cohort design was performed to assess any potential risk factors that may predispose to such fractures. Six of 2,220 hips (0.3%) suffered a periprosthetic femur fracture within the first year after surgery; five of six were Vancouver Type B2. The average time to fracture was 9 weeks. This group of patients had a significantly higher canal–flare index and lower canal–calcar ratio. This complication may be preventable by having a better appreciation of the fit between the implant and the bone during pre-operative planning, with the goal of avoiding a proximal–distal mismatch.     

Long-Term Durability of the CLS Femoral Prosthesis in Patients with Osteonecrosis of the Femoral Head

Ninety-five hips with cementless wedge-shaped tapered CLS stem were evaluated with a mean duration of 12.7 years (range, 10.7–17.3 years). All patients were young and diagnosed with osteonecrosis of the femoral head. The Harris hip score was 92 at the latest follow-up. A subsidence greater than 3 mm was found in 3 hips (3.2%). Focal femoral osteolysis was found in 12 hips (12.6%). Endosteal bone formation and bony pedestal were observed in 94 hips (98.9%) and in 26 hips (27.4%), respectively. With revision for stem loosening as the end point, the survivorship showed 98.9% (95% CI, range 96.9%–100%) at 13 years. Stem alignment and proximal femur morphology did not influence loosening of the stem (p > 0.05).     

Modern Revision Femoral Stem Designs Have No Difference in Rates of Subsidence

BackgroundBoth modular and monoblock tapered fluted titanium (TFT) stems have gained popularity over fully porous-coated cylindrical (FPCC) femoral stem designs, but limited data exist comparing subsidence rates following revision total hip arthroplasty (THA). The purpose of this study is to determine differences in subsidence and clinical outcomes among 3 revision femoral stem designs.MethodsWe reviewed a consecutive series of 335 patients who underwent femoral component revision to a cementless modular TFT (n = 225), monoblock TFT (n = 63), or FPCC (n = 47) stem between 2012 and 2019. We evaluated radiographic subsidence rates, re-revision rates, and patient-reported outcomes between the 3 stems. A multivariate regression analysis was performed to determine the independent effect of stem type on the risk of subsidence >5 mm.ResultsAt an average follow-up of 39 months (range, 12 to 96 months), there were no differences in mean subsidence rates (3.5 vs 2.4 vs 2.1 mm, P = .14), HOOS Jr scores (78 vs 74 vs 64 points, P = .15), or aseptic re-revision rates (4% vs 3% vs 0%, P = .29) between modular TFT, monoblock TFT, and FPCC stems. Although modular TFT stems were more often used in patients with extensive femoral bone loss (Paprosky III and IV), there were no differences in subsidence rates >5 mm among the 3 stems (P > .05) in multivariate analysis.ConclusionModular TFT, monoblock TFT, and FPCC femoral stem designs all perform well in revision THA with no difference in clinical outcomes or subsidence rates. Surgeons should select the stem which they feel is the most clinically appropriate.     

Prevalence,Risk Factors,and Management of Proximal Femoral Remodeling in Revision Hip Arthroplasty

The prevalence of, risk factors, and management of proximal femoral remodeling in revision total hip arthroplasty is unknown. Therefore, we reviewed the files of 200 consecutive femoral revision arthroplasties to study this phenomenon. Remodeling was considered present if a properly sized diaphyseal-engaging acrylic template had appropriate distal canal fill but lied within 2 mm of the proximal lateral endosteal cortex (definition 1) or completely outside the femoral canal (definition 2) on anteroposterior femoral radiographs. The prevalence of remodeling was 42% by definition 1 and 21% by definition 2. The strongest risk factors were loose femoral components and more severe femoral bone loss. Orthopedic surgeons performing revision arthroplasty should be prepared to encounter remodeling as its presence can complicate femoral component revision.     

Revision Total Hip Arthroplasty Using an Extensively Porous Coated Femoral Stem

Background

To determine the benefit of an extensively porous coated femoral stem in patients receiving revision total hip arthroplasty.

Methods

This study reviewed the results of 35 patients who received a revision total hip arthroplasty with extensively porous coated femoral stem between August, 1996, and December, 2002. The mean follow-up period was 77.5 months. The clinical and radiological results were evaluated by the Harris hip score and serial roentgenographic findings.

Results

The preoperative and postoperative Harris hip score was 68.3 and 92.5, respectively. Radiographically, none of the acetabular components showed any evidence of migration, tilt, rotation, or shedding of metal particles. In addition, none of the femoral components showed evidence of subsidence, pedestal, or shedding of metal particles. Twenty-two hips had a mild stress shield and 2 hips had a moderate stress shield. The perioperative complications encountered were deep vein thrombosis (1 case), mild heterotopic ossification (4 cases), intraoperative periprosthetic fractures (1 case), and nonunion of the trochanteric osteotomy site (2 cases).

Conclusions

Extensively porous coated femoral stems and acetabular components produce excellent clinical and radiological results in revision total hip arthroplasty.     

Cause-Specific Stem Revision Risk in Primary Total Hip Arthroplasty Using Cemented vs Cementless Femoral Stem Fixation in a US Cohort

BackgroundWe sought to evaluate the cause-specific revision risk following hybrid (cemented stem mated to a cementless acetabular implant) vs cementless total hip arthroplasty (THA) in a US cohort.MethodsPrimary elective THA for osteoarthritis was identified using Kaiser Permanente’s Total Joint Replacement Registry (2001-2018). Multivariable Cox regression was used to evaluate cause-specific revision, including aseptic loosening, infection, instability, and periprosthetic fracture (PPF), for hybrid vs cementless THA. Analysis was stratified by age (<65, 65-74, and ≥75 years) and gender.ResultsThe study cohort comprised 88,830 THAs, including 4539 (5.1%) hybrid THAs. In stratified analysis, hybrid THA had a higher revision risk for loosening in females in all 3 age subgroups. A lower risk of revision for PPF was observed following hybrid THA in females aged ≥75 years. For females ≥75 years, cementless THA had an excess PPF risk of 0.9% while hybrid THA had an excess loosening risk of 0.2%, translating to a theoretical prevention of 10 PPF revisions but a price of 3 loosening revisions per 1000 hybrid THAs. No difference in revision risk was observed in males.ConclusionWe observed differences in cause-specific revision risks by method of stem fixation which depended upon patient age and gender. Although the trend toward all cementless fixation continue, there may be a role for hybrid fixation in females ≥75 years to mitigate risk for revision due to PPF at the potential cost of a slight increase in longer term aseptic loosening.Level of EvidenceLevel III.     

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

Background

Although the popularity of the direct anterior approach for total hip arthroplasty has increased, the femoral procedure in this approach is considered technically challenging, and one of the most frequent complications reported was periprosthetic femoral fractures. The present study aimed to identify factors for predicting the risk of periprosthetic femoral fractures after using stems with a cementless tapered-wedge design through the direct anterior approach.

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.