Purpose

The purpose of this study is to evaluate the clinical outcomes and and radiological findings of primary total hip arthroplasty(THA) performed by using cemented polished femoral stem.

Introduction: The CPS-Plus stem (Endoplus UK) is a polished double-taper with a rectangular cross section maintained throughout for rotational stability. There are 5 stem sizes with proportionate offset, together with 5 neck length options, and a unique proximal stem centraliser which has been shown to increase proximal cement pressurisation during insertion in-vitro, assists with alignment of the stem and helps create an even cement mantle. RSA analysis has demonstrated linear subsidence in a vertical plane, without the posterior head migration and valgus tilt associated with other designs.

Data on the CPS-Plus stem has been obtained from a multi-centre prospective clinical trial. 231 hips in 223 patients have been entered into the study. 151 of these have reached 3 years follow-up.

Method: Patients were recruited by surgeons working at three centres in the UK and two in Norway. Merle d Aubigne and Postel, Harris, and Oxford hip scores were recorded pre-operatively and at follow-up (3, 6, 12, 24, 36, 60 months). Radiographic assessment included evaluation of subsidence and the presence of any radiolucencies.

Results: Objective and subjective scoring have indicated very satisfactory results. Radiological subsidence is less than 1.5mm in over 95% of cases and only one stem has subsided more than 3mm. There has been one revision for deep sepsis, 7 dislocations and one femoral fracture, but none of these complications were related to the choice of femoral component. There have been no revisions for aseptic loosening. Kaplan Meier survivorship analysis at 36 months for aseptic stem loosening is 0.997 (95% CI 0.977 – 1) and for all-cause revision is 0.981 (95% CI 0.958 – 1).

Discussion: The tradition of polished tapered stems arose from serendipity and most results have been excellent. The CPS-Plus stem represents an attempt to re-examine the issues relating to rotational stability, subsidence, cement pressurisation and offset. Earlier laboratory studies have now been supplemented by this clinical evaluation, performed in a number of different centres by several surgeons, and the evidence is encouraging.

In particular, the RSA subsidence characteristics, cement pressurisation and rotational stability already associated with this implant in-vitro have been supported by excellent survivorship analysis, and the authors believe that increasing familiarity with the concepts raised by this implant will result in clinical benefits in relation to polished taper cemented stem longevity.

Introduction The CPS-Plus stem (Endoplus UK) is a polished double-taper with rectangular cross section maintained throughout for rotational stability. There are 5 stem sizes with proportionate offset, and 5 neck length options. A unique proximal stem centraliser has been shown to increase proximal cement pressurisation during insertion in-vitro, also assists with alignment of the stem and helps create an even cement mantle. RSA analysis has demonstrated linear subsidence in a vertical plane, without posterior head migration and valgus tilt.

We report a multi-centre prospective clinical trial. 231 hips in 223 patients have been entered into the study. 151 of these have reached 3 years follow-up.

Method Patients were recruited by surgeons working at three centres in the UK, and two in Norway. Merle d Aubigne and Postel, Harris, and Oxford hip scores were recorded pre-operatively and at follow-up (3, 6, 12, 24, 36, 60 months). Radiographic assessment included evaluation of subsidence and the presence of any radiolucencies.

Results Hip scores have been very satisfactory. Radiological subsidence is less than 1.5mm in over 95% of cases and only one stem has subsided more than 3mm. There has been one revision for deep sepsis, 7 dislocations and one femoral fracture, but none of these complications were related to the choice of femoral component. There have been no revisions for aseptic loosening. Kaplan Meier survivorship analysis at 36 months for aseptic stem loosening is 0.997 (95% CI 0.977 – 1) and for all-cause revision is 0.981 (95% CI 0.958 – 1). 53 hips had reached 5-year follow-up at 30/9/04.

Discussion The tradition of polished tapered stems arose from serendipity and most results have been excellent. The CPS-Plus stem represents an attempt to re-examine the issues relating to rotational stability, subsidence, cement pressurisation and offset. Earlier laboratory studies have now been supplemented by this clinical evaluation, performed in a number of different centres by several surgeons, and the evidence is encouraging.

In particular, the RSA subsidence characteristics, cement pressurisation and rotational stability already associated with this implant in-vitro have been supported by excellent survivorship analysis, and the authors believe that increasing familiarity with the concepts raised by this implant will result in clinical benefits in relation to polished taper cemented stem longevity.

Vancouver B fractures around a cemented polished tapered stem (CTPS) are often treated with revision arthroplasty. Results of osteosynthesis in these fractures are poor as per current literature. However, the available literature does not distinguish between fractures around CTPS from those around other stems.

The aim of our study was to assess the clinical and radiological outcome of open reduction and internal fixation in Vancouver B fractures around CTPS using a broad non-locking plate.

Patients treated with osteosynthesis between January 1997 and July 2011 were retrospectively reviewed. All underwent direct reduction and stabilisation using cerclage wires before definitive fixation with a broad DCP. Bicortical screw fixation was obtained in the proximal and distal fragments. We defined failure of treatment as revision for any cause.

101 patients (42 men and 59 women, mean age 79) were included. 70 had minimum follow-up of 6 months. 63 of these went on to clinical and radiological union. Three developed infected non-union. 7 had failure of fixation. Lack of anatomical reduction was the commonest predictor of failure followed by inadequate proximal fragment fixation and infection. 14 patients dropped at least 1 mobility grade from their preoperative status.

This is the largest series of a very specific group of periprosthetic fractures treated with osteosynthesis. Patients who develop these fractures are often frail and “high risk” for major revision surgery. We recommend osteosynthesis for patients with Vancouver B periprosthetic fractures around CTPS provided these fractures can be anatomically reduced and adequately fixed.

Introduction The aim of this study was to describe the migration pattern of the Exeter stem after revision with morsellised allograft bone and cement, to evaluate if restricted weight bearing had any influence on migration, and to measure, before and after revision, the quality of life comparing it to primary cemented hip arthroplasties.

Methods Forty-one consecutive stem revisions were followed by radiostereometry (RSA, 1. Selvik 1989). The accuracy of the RSA set-up was between 0.3 mm and 0.7 mm. The surgical procedure described by the Exeter group (2. Gie 1993) was used. All were first time revisions for aseptic loosening and all patients had had their primary arthroplasty for osteoarthritis. Bone stock deficiency was classified according to Gustilo and Pasternak. Sixteen were type I, 20 type II, five type III but none was classified as type IV. The Nottingham Health Profile was used to measure quality of life before and after revision.

Results All stems migrated distally and most of them also migrated medially or laterally and posteriorly. Migration was still observed in one third of stems between 1.5 and two year follow-ups. At two years stem subsidence averaged 2.5 mm, medial or lateral migration averaged 1.2 mm and posterior migration averaged 2.9 mm. No correlation to the pre-operative bone stock deficiency was observed. Between two and five years only marginal migration occurred in 12 of the 15 stems followed for five years. No differences in the migration pattern were detected when free weight bearing was allowed immediately after revision in hips without intra-operative skeletal complications compared to when restricted weight bearing was practiced. Most migration occurs within the first two weeks after surgery. NHP scales for pain, physical mobility, sleep and energy scales improved significantly. NHP scores were in all six scales comparable to those of primary arthroplasties. No rerevision was performed and no stem had radiographic sings of loosening.

Conclusions Most migration occurred early after revision and decreased gradually. Marginal migration after two years does not deteriorate the results during the first five years after surgery. Quality of life (patient outcome) after revision with impacted morsellised allograft bone and cement was comparable to that of primary arthroplasties.

In relation to the conduct of this study, one or more of the authors is in receipt of a research grant from a non-commercial source.

Introduction & Aims: To study the survivorship and subsidence patterns of the first 433 Exeter polished, totally collarless, double tapered, cemented stems that were inserted between November of 1970 and the end of 1975 by 16 different surgeons (13 of them in the training grades) utilising first generation cementing techniques.

Method: A survivorship study up to the 33rd year of follow-up, using the contingency table method, was performed for all 433 hips, the end-point being revision for aseptic stem loosening. Stem subsidence in relation to the cement and the bone was measured in all survivors by a single observer on digitised films (magnified 200%) using the Orthochart™ software. Stem subsidence, the grade of cementing, ‘calcar’ resorption, visible cement fractures, focal lysis and radiolucent lines at the interfaces were assessed.

Results: Of the 433 hips, 21 were revisions of previously failed hips. 21.7% of patients have had a re-operation of some sort including 3.69% for stem fracture, 3.46% for neck fracture (all from a group of 95 stems with excessively machined necks), 9% for aseptic cup loosening, 3.46% for aseptic stem loosening, 1.84% for infection and 0.23% for recurrent dislocation). For the overall series, with revision for aseptic stem loosening as the end-point, the survivorship is 91.42% (95%CI: 70.82 to 100%). When all cases lost to follow-up (28 hips) are regarded as failures, survivorship is 82.9% (95%CI: 58.37 to 100%).

The average age at operation of the survivors was 55.7 years. No significant radiological subsidence between the cement and bone was found. Mean subsidence between the stem and the cement was 2.15mm, most occurring in the first 5 years and in all but 1 being less than 4. The maximum was 18mm (grade D cementing). Cementing grades were B in 65%, C in 27%, D in 8%. Resorption of the neck (13%) was associated with excessive socket wear or cement left over the cut surface of the neck (the ‘pseudocollar’). Visible cement fractures were found in 14%, none associated with focal lysis, which was seen in 11%.

Conclusions: Although 21.7% of patients in this series of the first 433 Exeter hips to be inserted in Exeter needed a re-operation of some sort, the stem rarely required surgery for aseptic loosening and was associated with benign long-term X-Ray appearances in spite of 1st generation cementing.

Introduction and Aims: To study the survivorship and subsidence patterns of the first 433 Exeter polished, totally collarless, double tapered, cemented stems that were inserted between November 1970 and the end of 1975 by 16 different surgeons (13 of them in the training grades) utilising first generation cementing techniques.

Method: A survivorship study up to the 33rd year of follow-up, using the contingency table method, was performed for all 433 hips, the end-point being revision for aseptic stem loosening (including also a ‘worst case’ scenario). Stem subsidence in relation to the cement and the bone was measured in all survivors by a single observer on digitised films (magnified 200%) using the Orthochart™ software. Repeated measurements allowed the analysis of intra-observer errors. Stem subsidence, the grade of cementing, ‘calcar’ resorption, visible cement fractures, focal lysis and radiolucent lines at the interfaces were assessed.

Results: Of the 433 hips, 21 were revisions of previously failed hips. 21.7% of patients have had a re-operation of some sort, including 3.69% for stem fracture, 3.46% for neck fracture (all from a group of 95 stems with excessively machined necks), 9% for aseptic cup loosening, 3.46% for aseptic stem loosening, 1.84% for infection and 0.23% for recurrent dislocation). For the overall series, with revision for aseptic stem loosening as the end-point, the survivorship is 91.42% (95%CI: 70.82 to 100%). When all cases lost to follow-up (28 hips) are regarded as failures, survivorship is 82.9% (95%CI: 58.37 to 100%).

The average age at operation of the survivors was 57.6 years. No significant radiological subsidence between the cement and bone was found. Mean subsidence between the stem and the cement was 2.15mm, most occurring in the first five years and in all but one being less than four. The maximum was 18mm (grade D cementing). Cementing grades were B in 65%, C in 27%, D in 8%. Resorption of the neck (13%) was associated with excessive socket wear or cement left over the cut surface of the neck (the ‘pseudocollar’). Visible cement fractures were found in 14%, none associated with focal lysis, which was seen in 11%.

Conclusion: Although 21.7% of patients in this series of the first 433 Exeter hips to be inserted in Exeter needed a re-operation of some sort, the stem rarely required surgery for aseptic loosening and was associated with benign long-term x-ray appearances in spite of 1st generation cementing.

Introduction and aims: To study the survivorship and subsidence patterns of the first 433 Exeter stems inserted between 1970 and 1975 by 16 different surgeons utilising first generation cementing techniques.

Method: A survivorship study up to the 33rd year of follow-up was performed, the end-point being revision for aseptic stem loosening. Stem subsidence was measured in all survivors, as well as assessing the grade of cementing, ‘calcar’ resorption, visible cement fractures, focal lysis and radiolucent lines at the interfaces.

Results: Of the 433 hips, 21 were revisions of previously failed hips. 21.7% of patients have had a re-operation of some sort including 3.69% for stem fracture, 3.46% for neck fracture (all from a group of 95 stems with excessively machined necks), 9% for aseptic cup loosening, 3.46% for aseptic stem loosening, 1.84% for infection and 0.23% for recurrent dislocation). For the overall series, with revision for aseptic stem loosening as the end-point, the survivorship is 91.42% (95%CI: 70.82 to 100%). The average age at operation of the survivors was 57.6 years. No significant bone-cement subsidence was found. Mean stem-cement subsidence was 2.15mm, most occurring in the first 5 years and in all but 1 being less than 4mm. Cementing grades were B in 65%, C in 27%, D in 8%. Resorption of the neck (13%) was associated with excessive socket wear or cement left over the cut surface of the neck (the ‘pseudocollar’). Visible cement fractures were found in 14%, none associated with focal lysis, which was seen in 11%.

Conclusions: Although 21.7% of patients in this series of the first 433 Exeter hips to be inserted in Exeter needed a re-operation of some sort, the stem rarely required surgery for aseptic loosening and was associated with benign long-term X-Ray appearances in spite of 1st generation cementing.

The Triple-tapered cemented polished C-Stem has evolved from the study of long-term results of the Charnley low-frictional torque arthroplasty when the first fractured stem and then proximal strain shielding of the femur and stem loosening were identified as the continuation of the same process- the lack or loss of proximal stem support.

The concept, design and the surgical technique cater for a limited slip of the C-stem within the cement mantle transferring the load more proximally. With a follow-up past 12 years and 4063 primary procedures there have been no revisions for aseptic stem loosening and no stem is radiologically loose.

We have reviewed 1008 primary C-Stem hip arthroplasties performed by 23 surgeons with a minimum of 5 years clinical and radiological follow-up. The mean follow-up was 7 years (range, 5 – 12) and the mean age at surgery was 57 years (range (15 – 85). In 58% the underlying pathology was primary osteoarthritis, 20% congenital dysplasia, 10% quadrantic head necrosis, 5% rheumatoid arthritis, 5% slipped upper femoral epiphysis and 4% protrusio acetabulae.

The concept of the triple tapered stem is validated radiologically with an improved proximal femoral bone stock in over 20% of cases and a maintained bone stock in 60%.

There were no post-operative complications within 1 year in 87% and no late complications (after 1 year) in 91%. The main late complications were 3.9% aseptic cup loosening, 1% infection and 0.8% dislocation. There were no aseptic loose stems.

Twenty-eight hips have been revised (2.8%), 3 for infection, 2 for dislocation and 23 for aseptic cup loosening. There were no revisions for aseptic stem loosening.

The results support the concept but place a demand on the understanding of the technique and its execution at surgery.

Aim of this study was to identify reoperation rates in patients with short oblique and transverse fractures around a well fixed cemented polished taper slip stem and to determine any associations with treatment failure.

Retrospective cohort study of 31 patients with AO transverse or short oblique Vancouver B1 PFFs around THA (total hip arthroplasty) cemented taper slip stems: 12 male (39%); mean age 74±11.9 (range 44–91); mean BMI 28.5±1.4 (range 16–48); and median ASA 3. Patient journeys were assessed, re-interventions reviewed. The primary outcome measure was reoperation.

Time from primary THA to fracture was 11.3±7.8yrs (0.5–26yrs). Primary surgical management was fixation in 27/31 and rTHA (revision total hip arthroplasty) in 4/31. 10 of 31 (32%) patients required reoperation, 9 within 2 years of fracture: 1 following rTHA and 8 following ORIF. The commonest mode of failure was non-union (n=6). No significant associations with reoperation requirement were identified. Kaplan-Meier free from reoperation was 67.4% (49.8–85.0 95% CI) at 2 years and this was unaffected by initial management with ORIF or rTHA (Log rank 0.898). Of those reoperated, 6/10 required multiple reoperations to obtain either bony union or a stable revision construct and 13% ultimately required proximal femoral endoprostheses. The relative risk of 1 year mortality was 1.6 (0.25 to 10.1 95%CI) among patients who required reoperation compared to those who did not.

These are difficult fractures to manage, should not be underestimated and patients should be counselled that there is a 30% risk of reoperation and 20% of requiring multiple reoperations.

The aim of the study was to report the survival of open reduction and internal fixation (ORIF) of Vancouver B fractures associated with the Exeter Stem (ES) at a minimum of 5 years.

This retrospective cohort study assessed 129 consecutive patients with Vancouver B type fractures treated with ORIF from 2008-2016 at a minimum of 5 years. Patient records were examined, and the following recorded: details of primary prosthesis, details of injury, Vancouver classification, details of operative management, complications, and requirement for reoperation. Data was analysed using SPSS. Survival analysis was undertaken using the endpoint ‘reoperation for any reason’.

Mean age at fracture was 78.2 (SD10.6, 46-96) and 54 (43%) were female. Vancouver subclassifications were: 24% B1, 70.5% B2 and 5.5% B3. For all Vancouver B fractures, Kaplan Meier analysis demonstrated a 5 year survival free from reoperation of 88.8% (82.0-94.7 95%CI). Fourteen patients required reoperation, most commonly within the first year for non-union and plate fracture (5.4%). Five-year survival for any reoperation differed significantly according to fracture type (p=0.016) and was worst in B1s: B1 76.6% (61.3-91.9); B2 92.6% 986.9-98.3); and 100% of B3. Univariate analysis identified B1 type (p=0.008) and a transverse fracture pattern (p=0.003) to be significantly associated with the need for reoperation.

Adopting a strategy of fixation of all Vancouver B fractures involving the ES where the fracture was anatomically reducible and the bone cement interface was well-fixed was associated with a 5 year survival, free from reoperation of 88.8%.

Aims

We aimed to compare the implant survival, complications, readmissions, and mortality of Vancouver B2 periprosthetic femoral fractures (PFFs) treated with internal fixation with that of B1 PFFs treated with internal fixation and B2 fractures treated with revision arthroplasty.

Aims

This study aimed to compare the change in health-related quality of life of patients receiving a traditional cemented monoblock Thompson hemiarthroplasty compared with a modern cemented modular polished-taper stemmed hemiarthroplasty for displaced intracapsular hip fractures.

The aim of this study is 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).

This is a retrospective cohort study of 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. Radiographs were assessed and classified by 3 observers. The primary outcome measure was revision of ≥1 component. Kaplan Meier survival analysis was performed. Logistic regression was used to identify risk factors for revision following ORIF. Secondary outcomes included any reoperation, complications, blood transfusion, length of hospital stay and mortality.

Fractures (B1 n=74 (49%); B2 n=50 (33%); and B3 n=28 (18%)) occurred at mean 6.7±10.4 years after primary THA (n=143) or hemiarthroplasty (n=15). Mean follow up was 6.5 ±2.6 years (3.2 to 12.1). Rates of revision and reoperation were significantly higher following revision arthroplasty compared to ORIF for B2 (p=0.001) fractures and B3 fractures (p=0.05). Five-year survival was significantly better following ORIF: 92% (86.4 to 97.4 95%CI) Vs 63% (41.7 to 83.3), p<0.001. No independent predictors of revision following ORIF were identified: fixation of B2 or B3 fractures was not associated with an increased risk of revision. Dislocation was the commonest mode of failure after revision arthroplasty. 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.

When the bone-cement interface was intact and the fracture was anatomically reducible, Vancouver B2 fractures around Exeter stems can be treated with fixation as opposed to revision arthroplasty. Fixation of Vancouver B3 fractures can be performed in frail elderly patients without increasing revision risk.

Background

We occasionally come across cortical atrophy of the femur with cemented collarless polished triple-taper stem, a short time after the operation. This study aimed to estimate the radiographs of cemented collarless polished triple-taper stem taken at three, six, twelve, and twenty-four months after the initial operation.

In revision hip surgery, a solidly cemented femoral component may obstruct access to the acetabulum, may be poorly orientated, or may have inadequate offset and head diameter. These problems can be addressed by revising the femoral component. The object of this study was to determine the outcome of cementing a polished, tapered, modular implant into the retained cement mantle. Benefits of cement within cement revision of a femoral stem include simplicity, reduced theatre time, and potentially reduced complication rates.

A consecutive series of 36 patients (11 men, 25 women) age range 35 to 90 years (mean age 70) underwent c stem cement in cement revision hip arthroplasty between June 2000 and April 2006. Indications for revision arthroplasty included 20 patients with aseptic acetabular loosening and 13 patients with recurrent instability. Follow up (12–84 months, mean 48 months) was annual and the outcome for every implant was known. Outcome measures included the shortened WOMAC score, Orthowave patient satisfaction survey, radiographic analysis, and assessment of the records for perioperative complications.

No patients were lost to follow up, 2 patients died with their hip in situ. The mean post operative WOMAC score at latest follow up was 10.89 (median 11, range 0 to 29). There has been no clinical or radiological signs of prosthesis loosening or failure on follow up. Complications included: one sacral plexus palsy which had a partial recovery, and one intra-operative periprosthetic fracture identified and treated at the time of the revision procedure. One patient underwent a further cup revision for recurrent dislocation.

Cement within cement revision hip arthroplasty using a highly polished tapered stem in the short to medium term provides satisfactory functional outcomes and is associated with low complication rates and good survivorship. Longer term results are awaited.

The Olympia femoral stem is a stainless steel, anatomically shaped, polished and three-dimensionally tapered implant designed for use in cemented total hip arthroplasty (THA). The primary aim of this study was to determine the long-term survivorship, radiographic outcome, and patient reported outcome measures (PROMs) of the Olympia stem.

Between May 2003 and December 2005, 239 patients (264 THAs) underwent a THA with an Olympia stem in our institution. PROMs were assessed using the Oxford Hip Score (OHS), EuroQol-5 dimensions (EQ-5D) score and patient satisfaction at mean 10-years following THA. Patient records and radiographs were then reviewed at a mean of 16.5 years (SD 0.7, 15.3 to 17.8) following THA to identify occurrence of complications or revision surgery for any cause.

Mean patient age at surgery was 68.0 years (SD 10.9, 31–93 years). There were 156 women (65%, 176 THAs). Osteoarthritis was the indication for THA in 204 patients (85%). Stem survivorship at 10 years was 99.2% (95 % confidence interval [CI], 97.9%-100%) and at 15 years was 97.5% (94.6%–100%). The 15-year stem survival for aseptic loosening was 100%. Only one occurrence of peri-prosthetic fracture was identified, with no episodes of dislocation found. At a mean of 10 (SD 0.8, 8.7 –11.3) years follow-up, mean OHS was 39 (SD 10.3, range 7 – 48) and 94% of patients reported being very satisfied or satisfied.

The Olympia stem demonstrated excellent 10-year PROMs, very high rates of stem survivorship and negligible peri-prosthetic fracture and dislocation rate at final follow-up beyond 15 years.

Background

We occasionally came across cortical atrophy of femurs with cemented collarless polished triple-taper stem in a short term period. This study aimed to estimate radiographs of cemented collarless polished triple-taper stem taken 6 months after the initial operation.

The triple taper polished cemented stem (C-stem, DePuy) was developed to promote calcar loading, and reduce proximal femoral bone resorption and aseptic loosening. We aimed to evaluate the changes in peri-prosthetic bone mineral density using Dual Energy X-ray Absorbtiometry (DEXA) after total hip arthroplasty (THA) using the C-stem prosthesis.

One hundred and three patients were recruited voluntarily through and single institution for THA. The prosthesis used was the triple-taper polished cemented C-Stem (De Puy, Warsaw, Indiana, USA). DEXA scans were performed pre- operatively, then at day for, three months, nine months, 18 months and 24 months post-operativley. Scans were analysed with specialised software (Lunar DPX) to measure bone mineral density (BMD) in all seven Gruen zones at each time interval. Changes in calcar BMD were also correlated with patient age, sex, surgical approach, pre-operative BMD and post-operative mobility to identify risk factors for periprosthetic bone resorption.

One hundred and three patients underwent 103 primary THA over a five-year period (98 osteoarthritis; 5 AVN). No femoral components were loose at the two year review and none were revised. The most marked bone resorption occured in Gruen zones 1 and 7, and was best preserved in zone 5. BMD decreased rapidly in all zones in the first three months post-operatively, after which the rate of decline slowed substantially. BMD was better preserved medially (zones 6 and 5) than laterally (zones 2 and 3) at 24 months. There was delayed recovery of BMD in all zones except zones 4 and 5.

High pre-operative T-scores (>2.0) in the spine, ipsilateral and contralateral femoral neck were associated with the higher post-operative BMD and less bone resorption at all time intervals in Gruen zone 7. Pre-operative osteopenia and osteoporosis were associated with low BMD and accelerated post-operative bone resorption in zone 7.

Patients whose mobility rendered them housebound had lower post-operative BMD, and accelerated post-operative BMD loss in zone 7 when compared to non-housebound patients. Females had a lower post-operative BMD and greater loss of BMD in zone 7. Patient age and surgical approach did not effect post-operative BMD or rate of bone resorption in zone 7.

The triple-taper femoral stem design did not show an increase in periprosthetic bone density at the proximal femur at two years post-operative. Calcar bone resorption is accelerated by low pre-operative BMD, poor post-operative mobility, and in females. Age and surgical approach do not have significant effects on calcar bone remodelling.