Satisfactory Results of the Exeter Revision Femoral Stem Used for Primary Total Hip Arthroplasty

A systematic review of short- compared with standard-length Exeter stems in primary total hip arthroplasty

Aims

The Exeter femoral stem has a cemented, polished taper-slip design, and an excellent track record. The current range includes short-length options for various offsets, but less is known about the performance of these stems. The aim of this study was to compare the survival of short-length stems with standard-length Exeter stems.

Methods

A systematic review of all studies reporting the use of short-length Exeter stems in primary total hip arthroplasty (THA) was undertaken. Survival data, the indication for revision, and patient-reported outcomes were gathered from observational and randomized studies. Studies based on registry data were analyzed separately.

Results

The review included nine studies which covered a total of 2,190 short stems. The mean follow-up was 6.4 years (2 to 12) with an all-cause survival of 95.4%. When revisions due to aseptic acetabular loosening were excluded, the survival was 97.7%. Four stems fractured (0.18%). The mean Oxford Hip Score improved from 18.29 (1.33 to 21.6) preoperatively to 41.59 (32.9 to 43.4) at final follow-up. Three studies used data from national registries. A total of 25,895 short stems (offset ≤ 35.5 mm) were used compared with 336,218 standard-length stems. In these studies, short stems had a hazard ratio (HR) for all-cause survival of 1.19 (95% CI 0.96 to 1.43) with a rate of revision per 1,000 component-years of 0.037 compared with 0.035 for standard-length stems. One study from the New Zealand Joint Registry divided short stems into standard and small offset groups. Standard offset short stems (≥ 37.5 mm) had a 0.84 HR (95% CI 0.38 to 1.88) while small offset short stems (≤ 35.5 mm) had a 1.6 HR compared with standard stems (95% CI 1.3 to 1.98).

Conclusion

Short Exeter stems perform well and are a safe femoral component in primary THA, according to the current literature. There does not appear to be an increased risk of implant fracture associated with these stems.

Mid-term outcomes after primary total hip arthroplasty with a cemented short stem in an elderly patient cohort

PURPOSE

The main objective of this prospective study was to assess clinical, radiographic and safety mid-term outcomes after THA with a short cemented stem in an elderly patient cohort. Moreover, the study aimed at investigating the mid-term survivorship of the implant and the incidence of complications.

METHODS

96 consecutive patients (100 cases) underwent THA with a short cemented stem. Underlying pathology was primary coxarthrosis in 93% of the cases. The clinical assessment was performed with the Harris Hip Score (HSS) and the Oxford Hip Score (OHS) and the radiographic evaluations were performed preoperatively, and at 45 days, 6, 12, 24 and 60 months postoperatively.

RESULTS

Patients' mean age at the time of surgery was of 73.4 years (range: 67.2-79.6 years). Mean HHS and OHS registered a significant improvement already 45 days after surgery, with the HHS increasing from 35.9 ± 11.3 (preoperative) to 79.2 ± 8.8 (45 days post-operatively) and the OHS increasing from 10.9 ± 4.8 (preoperative) to 34.1 ± 7.5 at 45 days (p < 0.001). Mean HHS and OHS at 5 years post operatively reached 97.2 ± 5.8 and 47.4 ± 1.4 points respectively. All implants were stable at the final follow-up with no cases of progressive radiolucent lines or osteolysis. No revisions were performed, with a survivorship of 100% at 5 years.

CONCLUSION

According to excellent clinical and patient-subjective outcomes and to the good implant stability with no component failure up to 5 years, this study suggests that the analysed short cemented stem could be a safe and performing treatment option for THA in elderly population.

LEVEL OF EVIDENCE

III.

CLINICALTRIALS

GOV IDENTIFIER

NCT04987437.

Survival of cemented short Exeter femoral components in primary total hip arthroplasty

Aims

The aim of this study was to report the long-term follow-up of cemented short Exeter femoral components when used in primary total hip arthroplasty (THA).

Methods

We included all primary 394 THAs with a cemented short Exeter femoral component (≤ 125 mm) used in our tertiary referral centre between October 1993 and December 2021. A total of 83 patients (21%) were male. The median age of the patients at the time of surgery was 42 years (interquartile range (IQR) 30 to 55). The main indication for THA was a childhood hip disease (202; 51%). The median follow-up was 6.7 years (IQR 3.1 to 11.0). Kaplan-Meier survival analyses were performed to determine the rates of survival with femoral revision for any indication, for septic loosening, for fracture of the femoral component and for aseptic loosening as endpoints. The indications for revision were evaluated. Fractures of the femoral component were described in detail.

Results

The 20-year rate of survival was 85.4% (95% confidence interval (CI) 73.9 to 92.0) with revision for any indication, 96.2% (95% CI 90.5 to 98.5) with revision for septic loosening and 92.7% (95% CI 78.5 to 97.6) with revision for fracture of the femoral component. No femoral components were revised for aseptic loosening. There were 21 revisions of the femoral component; most (seven) as part of a two-stage management of infection. Fracture of the femoral component occurred in four THAs (1.0%) at 6.6, 11.6, 16.5, and 18.2 years of follow-up, respectively. Three of these were transverse fractures and occurred at the level of the lesser trochanter. In one THA, there was a fracture of the neck of the component.

Conclusion

THAs using cemented short Exeter femoral components showed acceptable rates of survival of the femoral component at long-term follow-up, in this young cohort of patients. Although fracture is a rare complication of these components, surgeons should be aware of their incidence and possible risk factors.

Survival of the Exeter V40 short revision (44/00/125) stem when used in primary total hip arthroplasty

The Exeter V40 femoral stem is the most implanted stem in the National Joint Registry (NJR) for primary total hip arthroplasty (THA). In 2004, the 44/00/125 stem was released for use in 'cement-in-cement' revision cases. It has, however, been used 'off-label' as a primary stem when patient anatomy requires a smaller stem with a 44 mm offset. We aimed to investigate survival of this implant in comparison to others in the range when used in primary THAs recorded in the NJR. We analyzed 328,737 primary THAs using the Exeter V40 stem, comprising 34.3% of the 958,869 from the start of the NJR to December 2018. Our exposure was the stem, and the outcome was all-cause construct revision. We stratified analyses into four groups: constructs using the 44/00/125 stem, those using the 44/0/150 stem, those including a 35.5/125 stem, and constructs using any other Exeter V40 stem. In all 328,737 THAs using an Exeter V40 stem, the revision estimate was 2.8% (95% confidence interval (CI) 2.7 to 2.8). The 44/00/125 stem was implanted in 2,158 primary THAs, and the ten-year revision estimate was 4.9% (95% CI 3.6 to 6.8). Controlling for age, sex, year of operation, indication, and American Society of Anesthesiologists grade demonstrated an increased overall hazard of revision for constructs using the 44/00/125 stem compared to constructs using other Exeter V40 femoral stems (hazard ratio 1.8 (95% CI 1.4 to 2.3)). Although the revision estimate is within the National Institute for Health and Care Excellence ten-year benchmark, survivorship of constructs using the 44/00/125 stem appears to be lower than the rest of the range. Adjusted analyses will not take into account 'confounding by indication', e.g. patients with complex anatomy who may have a higher risk of revision. Surgeons and patients should be reassured but be aware of the observed increased revision estimate, and only use this stem when other implants are not suitable.

Analysis of the Exeter V40 femoral stem prosthesis fracture : systematic review and single centre case series

Aims

The Exeter V40 cemented polished tapered stem system has demonstrated excellent long-term outcomes. This paper presents a systematic review of the existing literature and reports on a large case series comparing implant fractures between the Exeter V40 series; 125 mm and conventional length stem systems.

Methods

A systematic literature search was performed adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria. In parallel, we performed a retrospective single centre study of Exeter V40 femoral stem prosthetic fractures between April 2003 and June 2020.

Results

There are 25 reported cases of such prosthetic fractures confined to small case series and case reports within the literature. We report an additional 19 cases to the literature (mean age 66.3 years (SD 11.7); 12 (63%) females; BMI 32.9 kg/m² (SD 5.9)). The mean time from index procedure to fracture was 7.8 years (SD 3.6; 2.5 to 16.3). Exeter V40 stem fracture incidence was 0.15% and 1.21% for primary and revision arthroplasty, respectively. Incidence was significantly higher in revision arthroplasty (p < 0.001) and 125 mm length stems compared to ≥ 150 mm length stems (1.25% vs 0.13%, respectively; p < 0.001). When comparing different stem length cohorts, 125 mm short-stems were associated with stem-body fractures (92% vs 29%; p = 0.0095), earlier time to fracture (6.2 years vs 11.0 years; p = 0.0018), younger patient age at time of fracture (62.7 years vs 72.6 years; p = 0.037), and female sex (75% vs 43%; p = 0.326).

Conclusion

This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. Short 125 mm length Exeter V40 stems undoubtedly have a role in restoring anatomy and biomechanics in smaller femoral geometries, although the surgeon has to appreciate the higher risk of stem fracture and the associated predisposing factors which may necessitate particular attention to surgical technique and planning.

Cite this article: Bone Jt Open 2021;2(6):443–456.

The Exeter Short Revision Stem for Cement-in-Cement Femoral Revision: A Five to Twelve Year Review

BACKGROUND

Cement-in-cement femoral revision is a proven technique in revision total hip arthroplasty, with excellent results reported using standard-sized Exeter stems. The Exeter 44/00/125 short revision stem was introduced in 2004 to facilitate cement-in-cement revision. The stem is 25-mm shorter and has a slimmer body than standard stems to facilitate adjustment of depth of insertion and stem version. It is not known if this change in stem size affects its long-term performance. We therefore reviewed the outcome of all Exeter short revision stems used for cement-in-cement revision in our unit, with a minimum of 5 years of follow-up.

METHOD

One hundred sixty-six cases were performed between 2004 and 2010. Mean follow-up of surviving patients was 8.1 years (range 5.0-11.7). The fate of all 166 hips were known and included in the survival analysis.

RESULTS

Median clinical scores improved significantly. Sixteen hips required re-revision (infection 6, loose cup 3, periprosthetic fracture 3, instability 2, stem fracture with chronic infection 1, and pain 1). Kaplan-Meier survival analysis at 10 years revealed 100% survival for aseptic stem loosening, 96.8% survival for stem failure, and 88.9% survival for all causes.

CONCLUSION

The Exeter short revision stem performed as well as standard length stems for cement-in-cement revision in this the largest and longest review of their use. Larger registry-based studies may provide additional information on the performance of this stem.