Aims. The Exeter short stem was designed for patients with Dorr type A femora and short-term results are promising. The aim of this study was to evaluate the minimum five-year stem migration pattern of Exeter short stems in comparison with Exeter standard stems. Methods. In this case-control study, 25 patients (22 female) at mean age of 78 years (70 to 89) received cemented Exeter short stem (case group). Cases were selected based on Dorr type A femora and matched first by Dorr type A and then age to a control cohort of 21 patients (11 female) at mean age of 74 years (70 to 89) who received with cemented Exeter standard stems (control group). Preoperatively, all patients had primary hip osteoarthritis and no osteoporosis as confirmed by dual X-ray absorptiometry scanning. Patients were followed with radiostereometry for evaluation of stem migration (primary endpoint), evaluation of cement quality, and Oxford Hip Score. Measurements were taken preoperatively, and at three, 12, and 24 months and a minimum five-year follow-up. Results. At three months, subsidence of the short stem -0.87 mm (95% confidence interval (CI) -1.07 to -0.67) was lower compared to the standard stem -1.59 mm (95% CI -1.82 to -1.36; p < 0.001). Both stems continued a similar pattern of subsidence until five-year follow-up. At five-year follow-up, the short stem had subsided mean -1.67 mm (95% CI -1.98 to -1.36) compared to mean -2.67 mm (95% CI -3.03 to -2.32) for the standard stem (p < 0.001). Subsidence was not influenced by preoperative bone quality (osteopenia vs normal) or cement mantle thickness. Conclusion. The standard Exeter stem had more early subsidence compared with the short Exeter stem in patients with Dorr type A femora, but thereafter a similar migration pattern of subsidence until minimum five years follow-up. Both the standard and the short Exeter stems subside. The standard stem subsides more compared to the short stem in Dorr type A femurs. Subsidence of the Exeter stems was not affected by cement mantle thickness. Cite this article: Bone Jt Open 2023;4(7):507–515

Aims

The aim of this study is to report the long-term outcomes of instrumented femoral revisions with impaction allograft bone grafting (IBG) using the X-change femoral revision system at 30 years after introduction of the technique.

Previously, radiostereometric analysis following hip revision performed using impacted morsellised allograft bone and a cemented Exeter stem has shown continuous subsidence of the stem for up to five years. It is not known whether the subsidence continues thereafter. In our study, 17 of 25 consecutive osteo-arthritic patients with aseptically loose stems who underwent first-time revision using impacted morsellised allograft bone and a cemented Exeter stem were followed by yearly radiostereometric examinations for nine years. The mean subsidence at six weeks was 1.1 mm (0.1 to 2.3), from six weeks to one year 1.3 mm (0 to 2.6), from one to five years 0.7 mm (0 to 2.0), and from five to nine years 0.7 mm (0.1 to 3.1). That from six weeks to nine years was 2.7 mm (0 to 6.4) (95% confidence interval 2.0 to 3.5). The Charnley pain score significantly improved after revision, and was maintained at nine years, but walking ability deteriorated slightly as follow-up extended. Of the eight patients who were not followed for nine years, two had early subsidence exceeding 11 mm. Our findings show that in osteo-arthritic patients who undergo revision for aseptic loosening of the stem using impacted morsellised allograft bone and a cemented Exeter stem, migration of the stem continues over nine years at a slower rate after the first year, but without clinical deterioration or radiological loosening

We identified 1305 femoral impaction bone grafting revisions using the Exeter stem performed between 1989 and 2002 in 30 hospitals throughout Sweden. There were 1188 patients with a mean age of 71 years (29 to 94) followed up for between five and 18 years. The participating departments reported 70 further revisions in total, of which 57 could also be identified on the Swedish National Arthroplasty Registry. Kaplan-Meier survivorship for all causes of failure was 94.0% (95% confidence interval (CI) 92 to 96) for women and 94.7% (95% CI, 92 to 96) for men at 15 years. Survivorship at 15 years for aseptic loosening was 99.1% (95% CI 98.4 to 99.5), for infection 98.6% (95% CI 97.6 to 99.2), for subsidence 99.0% (95% CI 98.2 to 99.4) and for fracture 98.7% (95% CI 97.9 to 99.2). Statistically significant predictors of failure were the year in which revision was conducted (p < 0.001). The number of previous revisions was slightly above the level of signifance (p = 0.056). Age, gender, the length of the stem and previous septic loosening were not predictors of failure (p = 0.213, p = 0.399, p = 0.337, p = 0.687, respectively). The difference in survivorship between high- and low-volume departments was only 3% at ten years. We conclude that impaction bone grafting with the Exeter stem has an excellent long-term survivorship following revision arthroplasty. The technique of impaction grafting appears to be reliable, can be learned rapidly and produces a predictably low incidence of aseptic loosening

The Exeter totally collarless, double-tapered femoral component was developed in 1969 jointly at the School of Engineering at the University of Exeter and the old Princess Elizabeth Orthopaedic Hospital. At the time, in common with a number of implants in contemporary use, the new Exeter stem was manufactured from the rather ductile stainless steel EN58J. The original version of the Exeter stem had a polished surface. This feature was not part of the original design specification, but was demanded by the current British standard governing the use of EN58J in orthopaedic implants. At that time, no thought was given to the possibility that the surface finish of the stem might influence outcome. Used from 1970 to 1975, the original stems rarely came to need replacement because of loosening. The major complication was the incidence of stem fracture, first seen in 1973, which has reached 4% over a 25 to 30 year follow-up. A stronger stem was introduced at the beginning of 1976. This was manufactured from 316L. As there was no standard demanding a polished surface, this stem was manufactured with a surface two orders of magnitude rougher than the surface of the original polished Exeter stems. While the introduction of this stem almost completely solved the problem of stem fracture, with it appeared notable problems of femoral endosteal bone lysis and aseptic stem loosening, hardly seen with the original polished stems. The study of retrieved prostheses showed the matt surface stem to be prone to abrasive wear against the inside of the cement mantle, and that this phenomenon could lead both directly and indirectly to stem loosening. Unfortunately, a decade passed before the polished stem was re-introduced in 1986. A monobloc version was used until the beginning of 1988, when the modular Exeter Universal stem was introduced. With both the monobloc and modular versions of the polished Exeter stem, both aseptic loosening and localised endosteal bone lysis have become rare. Further retrieval studies have shown that in polished and matt Exeter stems the wear processes between stem and cement are fundamentally different. This difference may explain the substantial clinical difference in outcome between these two types of stem. These considerations lead to the view that abrasive stem wear in matt stems is probably a major cause of failure, and more important than failure of cement

Introduction: The design philosophy of polished tapered THR stems, such as the Exeter, intend for them to migrate distally within the cement mantle. In addition it is likely that micromotion occurs as a result of functional activity. The pattern of induced stresses will be a function of stem geometry & surface finish, as well as applied loading. Aim: To investigate the stresses induced in the cement mantle of a polished tapered THR stem during functional activity. Method: Using Roentgen Stereophotogrammetric Analysis (RSA) dynamically induced micro-motion (DIMM) was measured in 21 patients implanted with Exeter stems. DIMM was measured as the difference in stem position in going from double to single leg stance on the operated limb. All subjects were measured 3 months post-operatively. A finite element (FE) model of the femur, including all muscles was used to investigate the stress distribution within the cement; contact was modelled with sliding elements allowing separation. The model was validated by comparison to the DIMM measurements. Results: The Exeter stem demonstrated significant DIMM(p < 0.017), the average motions are given in the table below. The FE model, with sliding contacts was able to predict similar distal migration of the head. The peak minimum principal stress in the mantle was approx 33MPa and occurred in the proximal medial region. Movements occurred at the stem/cement interface. Discussion and Conclusion: It is possible to measure DIMM in the Exeter stem and combining this with FE modelling the mechanism of stress transfer between the stem and mantle can be investigated in a manner that can be validated

The Exeter Stem (Howmedica, UK) has been in use for over 35 years. Over the years it has undergone several modifications with the most recent being a highly polished, tapered stem in 1986. The manufacturers quote a rate of 0.0006%. In the current literature there are 16 (or less) instances of fractures of the Orthinox stem. We present a case of fracture of an Orthinox Exeter Stem 9 years after insertion. Our patient, BB, presented, aged 62, with symptoms & signs consistent with OA right hip. THR was performed through a lateral approach utilising a trochanteric osteotomy. A size 0 37.5 stem was inserted. Radiographs were very satisfactory. She suffered a post operative DVT/PTE from which she recovered uneventfully. She was independently mobile at 6 month review and was discharged at the 2 year stage pain free. Aged 71, BB presented to outpatient clinic with a several month history of generalised groin pain. She had a Trendelenberg gait. Considerable pain was experienced on axial compression of the limb. Radiographs revealed a midstem fracture with cement loosening proximally. No trauma was reported. She underwent revision surgery through a posterior approach. Acetabular component was rigidly fixed. This was revised to a pressfit Trident (Zimmer, UK) cup with screws & polyethylene liner. An extended trochanteric osteotomy was used to remove the broken stem. An uncemented Restoration (Stryker, UK) stem was inserted with a 28mm head. Post-operative recovery was unremarkable and at 6 months osteotomy has healed. The stem was sent to Stryker UK Laboratories for analysis. They reported the stem broke in fatigue with the origin on the antero-lateral surface. No material or manufacturing defects seen. Dimensionally correct. Fracture may be due to abnormal bending stresses secondary to proximal loosening and firm distal fixation. Our case demonstrates a set of circumstances that led to inevitable fatigue and stem fracture. The method of failure should reinforce the radiograph appearances that may cause concern or be acted upon

Purpose. Exeter stem was introduced to Japanese market at 1996. Since then, owing to its excellent clinical results, the number of the stem used has been increased year by year and more than 2000 stems have been implanted during the year 2009. The present study aims to prove its efficacy for Japanese patients by evaluating short term results of four major dedicated hip centers. Method. We present the short-term multi-center results of primary THA with Exeter stem combined with modern cementing technique in 881 patients (1000 hips). The average age of the patients at operation was 62.3years (ranging 23 to 89 years). Mean postoperative follow up period was 4.0 (ranging 2 to 9) years. Results. Intraoperative complications such as femoral fracture were observed in 6 hips. Postoperative cementing grade using Barrack's classification was judged as A for 735 hips, as B for 246 hips, and as C for 4 hips, respectively. Twenty-four patients died with unrelated disease and 52 patients were lost during follow-up period. Follow-up ratio was 94.8%. Thirty postoperative complications which include 9 infections, 14 dislocations, 5 deep vein thrombosis, and 2 sciatic nerve palsies were observed. Symptomatic pulmonary embolization or femoral fracture was not observed. Re-operations for infection and dislocation were performed for 8 and 6 hips, respectively. At the final follow-up, no radiolucent line at bone-cement interface was observed. Cortical hypertrophy was observed in 9.6% at Gruen zone 2 to 6. Kaplan-Meier survivorship analysis predicted a rate of survival at 5 years of 100% with radiolucent line at bone-cement interface of the femur as the endpoint, and of 98.8% when re-operation for any reason was used. Conclusion. The present study revealed excellent short-term result was obtained using Exeter stem combined with modern cementing technique for primary THAs in Japan

To determine if any notable differences between a cemented Thompson stem hemiarthroplasty and a cemented Exeter stem hemiarthroplasty (ETS), 200 patients with a displaced intracapsular fracture were randomised between the two prosthesis. Surviving patients were followed-up for one year by a nurse blinded to the treatment allocation. The mean age of patients was 84 years and 13% were male. There were no differences between groups for the length of surgery, need for blood transfusion or hospital stay. Implant related complications were three minor operative fractures of the femur in each group. Two patients in the Thompson group had dislocation of the prosthesis requiring revision surgery and one further patient in the Thompson group had late acetabular wear requiring conversion to a total hip replacement. One further patient in the Thompson group had cement retained in the acetabulum. In total therefore only three patients, all in the Thompson group, which required revision surgery. Easy of surgery was assessed subjectively by the surgeon and reported to be easier for the ETS group (p=0.0002). During follow-up there was no significant difference in the degree of residual pain between groups. Conclusions are that the cemented Exeter stem hemiarthroplasty has some advantages over the traditional cemented Thompson hemiarthroplasty

Introduction. Despite being from different manufacturers, Exeter stem and Ogee cup are commonly used together as cemented ‘cross breed’ combination in United Kingdom. The purpose of this study was to evaluate the long-term outcome of this combination. Materials and methods. The ten years outcome of 131 primary hip replacements using an Exeter stem and an Ogee cup combination were studied retrospectively from clinical audit data and radiographs. Results. The Harris Hip score (HHS) improved significantly from 46 pre-surgery to 88 post-surgery. This had a gradual decrease to 81 over ten years. This effect was associated with a decrease in function score but a sustained pain score. Radiologically, five cups were loose and two stems had failed. One stem had migrated and another had progressive endosteolysis. There were two recurrent dislocations, of which one was revised to a bipolar socket. The ten year survival of the combination implant was 99% (CI 97 to 100) with revision as an end point. The same with impending failure as end point was 93% (CI 87 to 99). Conclusion. It might be preferable to have a multi-centric prospective study to demonstrate the performance of this commonly done combination implant at various settings. In the meantime it is concluded that the Exeter stem-Ogee cup combination arthroplasty has acceptable outcomes at ten years

Introduction. Varus alignment of the femoral component in total hip arthroplasty (THA) is thought to be a risk factor for implant loosening and early revision surgery. The purpose of this study was to evaluate whether the Exeter stem tolerates varus alignment and assess if this theoretical malalignment has an influence on clinical outcomes. Methods. A total of 4126 consecutive THAs were reviewed for patients between 2006 and 2012 to allow for a minimum five-year follow-up. To determine the effects of the stem alignment on results, the hips were classified into 3 groups on the basis of stem alignment in initial postoperative anteroposterior radiographs. The alignment of the stem was defined as neutral, valgus (≥ 3° of lateral deviation), or varus (≥ 3° of medial deviation). The primary outcome was all cause revision with patient related outcomes assessed with Oxford hip score pre and post-operatively. Results. The mean follow-up period was 8.6 years. 3803 (92.2%), 48 (1.2%), and 275 (6.7%) hips were assessed as neutral, valgus, and varus alignment, respectively. Assessment of outcomes showed that 75 revision surgeries (1.8%) were performed during follow-up for a variety of causes but there was no significant difference in the revision rate among the 3 alignment groups. No stems were revised for aseptic loosening in any of the three groups. Oxford Hip scores were obtained at a mean of 4.6 years post-operatively and no significant difference in patient reported outcome was identified between the different alignment groups. Conclusion. This study suggests that the Exeter stem tolerates varus alignment well with no demonstrable effect on revision rate or patient reported outcome. This tolerance of malposition compared to the negative results reported in the literature with other stem designs can be of reassurance to surgeons using the Exeter system

Femoral stem varus has been associated with poorer results. We report the incidence of varus/valgus malalignment of the Exeter polished, double taper design in a multicentre prospective study. The surgical outcomes at a minimum of five year and complication rates are also reported. A multicentre prospective study of 987 total hip replacements was undertaken to investigate whether there is an association between surgical outcome and femoral stem malalignment. The primary outcome measure was the change in the Oxford hip score (OHS) at five years. Secondary outcomes included the rate of dislocation and revision. The incidence of varus and valgus malignment were 7.1% and 2.6% respectively. There was no significant difference in OHS between neutral and malaligned femoral stems at 5 years (neutral, mean = 40.2; varus, mean 39.3, p = 0.465; valgus, mean = 40.9, p = 0.605). There was no significant difference in dislocation rate between the groups (p = 0.66). There was also no significant difference in revision rate (p = 0.34). This study provides evidence that the Exeter stem is extremely tolerant of varus and valgus malalignment, both in terms of outcome and complication rate

We report the clinical and radiographic outcomes of 208 consecutive femoral revision arthroplasties performed in 202 patients (119 women, 83 men) between March 1991 and December 2007 using the X-change Femoral Revision System, fresh-frozen morcellised allograft and a cemented polished Exeter stem. All patients were followed prospectively. The mean age of the patients at revision was 65 years (30 to 86). At final review in December 2013 a total of 130 patients with 135 reconstructions (64.9%) were alive and had a non re-revised femoral component after a mean follow-up of 10.6 years (4.7 to 20.9). One patient was lost to follow-up at six years, and their data were included up to this point. Re-operation for any reason was performed in 33 hips (15.9%), in 13 of which the femoral component was re-revised (6.3%). The mean pre-operative Harris hip score was 52 (19 to 95) (n = 73) and improved to 80 (22 to 100) (n = 161) by the last follow-up. Kaplan–Meier survival with femoral re-revision for any reason as the endpoint was 94.9% (95% confidence intervals (CI) 90.2 to 97.4) at ten years; with femoral re-revision for aseptic loosening as the endpoint it was 99.4% (95% CI 95.7 to 99.9); with femoral re-operation for any reason as the endpoint it was 84.5% (95% CI 78.3 to 89.1); and with subsidence ≥ 5 mm it was 87.3% (95% CI 80.5 to 91.8). Femoral revision with the use of impaction allograft bone grafting and a cemented polished stem results in a satisfying survival rate at a mean of ten years’ follow-up. Cite this article: Bone Joint J 2015; 97-B:771–9

The Exeter stem is a polished cemented stem that has been associated with an excellent survivorship. However, this wedge shaped stem has also been associated with a relative higher risk for a peri-periprosthetic fracture due to the wedge-shaped configuration that can lead to a Vancouver type B2 fracture when the stem is being driven downwards inside the femoral canal by a traumatic blast. Traditionally, these fractures should be treated with a revision stem because the stem has become loosened in the fractured cement mantle. We present a case series of 5 cases where our treatment algorithm was to first let the non-displaced fracture to consolidate by 6 weeks of limited weight bearing as tolerated in order to conduct a second stage in-cement revision. This would simplify the revision procedure dramatically. However, all patients are currently pain free and do not require revision surgery although they are being monitored very closely. We conclude that non-displaced Vancouver type B2 fractures can be approached by a 2 stage treatment algorithm where the initial step is to let the fracture consolidate with limited weight bearing

Aims. 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. Methods. 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. Results. 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)). Conclusion. 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. Cite this article: Bone Joint J 2023;105-B(5):504–510

Aims. The aim of this study was to determine whether fixation, as opposed to revision arthroplasty, can be safely used to treat reducible Vancouver B type fractures in association with a cemented collarless polished tapered femoral stem (the Exeter). Methods. This retrospective cohort study assessed 152 operatively managed consecutive unilateral Vancouver B fractures involving Exeter stems; 130 were managed with open reduction and internal fixation (ORIF) and 22 with revision arthroplasty. Mean follow-up was 6.5 years (SD 2.6; 3.2 to 12.1). The primary outcome measure was revision of at least one component. Kaplan–Meier survival analysis was performed. Regression analysis was used to identify risk factors for revision following ORIF. Secondary outcomes included any reoperation, complications, blood transfusion, length of hospital stay, and mortality. Results. Fractures (B1 n = 74 (49%); B2 n = 50 (33%); and B3 n = 28 (18%)) occurred at median of 4.2 years (interquartile range (IQR) 1.2 to 9.2) after primary total hip arthroplasty (THA) (n = 138) or hemiarthroplasty (n = 14). Rates of revision and reoperation were significantly higher following revision arthroplasty compared to ORIF for B2 (p = 0.001) and B3 fractures (p = 0.050). Five-year survival was significantly better following ORIF: 92% (95% confidence interval (CI) 86.4% to 97.4%) versus 63% (95% CI 41.7% to 83.3%), p < 0.001. ORIF was associated with reduced blood transfusion requirement and reoperations, but there were no differences in medical complications, hospital stay, or mortality between surgical groups. No independent predictors of revision following ORIF were identified: where the bone-cement interface was intact, fixation of B2 or B3 fractures was not associated with an increased risk of revision. Conclusion. When the bone-cement interface was intact and the fracture was anatomically reducible, all Vancouver B fractures around Exeter stems could be managed with fixation as opposed to revision arthroplasty. Fixation was associated with reduced need for blood transfusion and lower risk of revision surgery compared with revision arthroplasty. Cite this article: Bone Joint J 2021;103-B(2):309–320

Bone impaction grafting of the femur is associated with more complications when segmental defects are present. The effect of segmental defect repair on initial stem stability was studied in an in vitro study with fresh frozen goat femora. A standardized medial segmental defect was reconstructed using a cortical strut or a metal mesh. As controls we used intact femora and femora with a non-reconstructed defect. In all four groups impacted bone grafting was performed in combination with a cemented Exeter stem. Each group contained five femora. Reconstructions were dynamically loaded up to 1500N. Migration was measured with Roentgen Stereo-photogrammetric Analysis. All cases with a non-reconstructed segmental defect failed into excessive varus rotation. None of the femora with a reconstructed defect failed. Cortical struts and metal meshes were equally effective in creating a stable stem construction (varus rotation 2.89±2.27 and 2.27±0.57, respectively). Reconstructions with a metal mesh were more reproducible, although the obtained stability was significantly lower (p< 0.01) when compared to impaction grafting in an intact femur (varus rotation 0.58±0.36). Besides, structural grafts may negatively influence the revascularization of the underlying impacted grafts in contrast to an open wire mesh. So, an in vivo study of 12 goats was done. A standardized medial wall defect was reconstructed with a strut or a mesh in six goats per group. In all femora impaction grafting was performed in combination with a cemented Exeter stem. After six weeks the femora were harvested. A high rate of peri-prosthetic fractures was found (43% and 29% for the strut and mesh groups, respectively). Histological and micro-radiological examination showed different revascularization patterns for both reconstruction techniques. In the strut group revascularized graft was found at the edges of the defect. In the mesh group fibrous tissue and blood vessels penetrated through the mesh and a superficial zone of revascularized grafts was found. Segmental defect reconstruction with a strut reduced the amount of revascularized grafts medially behind the strut (p=0.004). This may interfere with the stability of the stem in the first period after surgery and the incorporation of the impacted grafts on the long-term. We would recommend segmental defect reconstruction with a mesh. A regime of unloading and long-stem prostheses should be used, irrespective of the reconstruction technique

We evaluated all cases involving the combined use of a subtrochanteric derotational femoral shortening osteotomy with a cemented Exeter stem performed at our institution. With severe developmental dysplasia of the hip an osteotomy is often necessary to achieve shortening and derotation of the proximal femur. Reduction can be maintained with a 3.5 mm compression plate while the implant is cemented into place. Such a plate was used to stabilise the osteotomy in all cases. Intramedullary autograft helps to prevent cement interposition at the osteotomy site and promotes healing. There were 15 female patients (18 hips) with a mean age of 51 years (33 to 75) who had a Crowe IV dysplasia of the hip and were followed up for a mean of 114 months (52 to 168). None was lost to follow-up. All clinical scores were collected prospectively. The Charnley modification of the Merle D’Aubigné-Postel scores for pain, function and range of movement showed a statistically significant improvement from a mean of 2.4 (1 to 4), 2.3 (1 to 4), 3.4 (1 to 6) to 5.2 (3 to 6), 4.4 (3 to 6), 5.2 (4 to 6), respectively. Three acetabular revisions were required for aseptic loosening; one required femoral revision for access. One osteotomy failed to unite at 14 months and was revised successfully. No other case required a femoral revision. No postoperative sciatic nerve palsy was observed. Cemented Exeter femoral components perform well in the treatment of Crowe IV dysplasia with this procedure

Introduction: Implantation of a THA changes the strain distribution pattern in the proximal femur, with a massive loss of stress in the proximal part of the femur and an increase in stress at the distal part of the femoral component. Aim: The purpose of this study was to quantify the changes in BMD during long-term follow-up, i.e. five years, after insertion of the collarless, two-side conical, cemented Exeter stem. Material & Methods: Eighteen patients (all women), aged 55 to 80 years, undergoing THA were included in the study after informed consent. BMD was measured in 7 regions of interest according to Gruen et al., using Dual Energy X-ray Absorptiometry postoperatively, after 18 and 60 months of follow-up. At the same time, the contra lateral hip and spine were scanned. Results were tested using Wilcoxon matched-pairs signed-rank test. P values below 0.05 were considered significant. Results: During the first 18 months, a significant decrease in BMD was present in Gruen zones 2, 3, 6, and 7. No significant changes were seen in BMD of the zones 4, and 5 in the contra lateral hip, nor at the spine. In zone 1 there was a small but significant rise in BMD. From 18 to 60 months of follow up we observed a significant rise in BMD in all Gruen zones but zone 4 and 7. Despite this the total periprostetic BMD decreased during the study periode. There was no significant decrease in BMD in the contra lateral hip. In the spine, we observed a significant rise in BMD. Conclusion: During short-term follow-up (i.e. 18 months) after THA, BMD decreased in Gruen zones 2, 3, 6 and 7. The bone loss is similar to findings in other implants and seems to be related to the changes in stress pattern within the proximal femur. During long-term follow-up (i.e. 5 years) BMD increased again in these zones, however, BMD remained lower than baseline

Recent NICE guidance recommends use of a well proven cemented femoral stem for hip hemiarthroplasty in management of fractured neck of femur. The Exeter Trauma Stem (ETS) has been designed based on the well proven Exeter hip stem. It has a double taper polished stem design, proclaimed to share geometry and surface finish with the Exeter hip. This study investigated the surface finish of the two stems in order to investigate the hypothesis that they were different. Two ETS and two Exeter stems were examined using a profilometer with a sensitivity of one nanometer. Macroscopic visual inspection showed that the two Exeter stems had significantly smoother surface finish than the ETS stems. The roughness average (RA) values on the ETS stems were approximately an order of magnitude higher than those of the Exeter stems, mean of 0.235μm compared with 0.025μm (p<0.0001). This difference in surface finish has implications for the biomechanical functioning of the stem. Previous change of the Exeter stem to a matt surface-finish in 1976 resulted in a significant increase in stem failure rates and an understanding of the importance of the polished surface-finish in order to function within a taper-slip philosophy. By changing the surface finish in the ETS stem, longevity of the implant may similarly be affected. Clinical results have yet to be published demonstrating this. We recommend the manufacturer reconsiders the surface finish of the ETS stem to ensure it functions as well as the Exeter primary stem with which it shares a design philosophy