Aims

Treatment of high-grade limb bone sarcoma that invades a joint requires en bloc extra-articular excision. MRI can demonstrate joint invasion but is frequently inconclusive, and its predictive value is unknown. We evaluated the diagnostic accuracy of direct and indirect radiological signs of intra-articular tumour extension and the performance characteristics of MRI findings of intra-articular tumour extension.

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.

A systematic literature search was performed adhering to PRISMA criteria. In parallel we performed a retrospective single centre study of Exeter^™ V40 femoral stem prosthetic fractures between April 2003– June 2020.

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 ± 11.7 years; 12 female [63%]; body mass index 32.9 ± 5.9 kg/m²). The mean time from index procedure to fracture was 7.8 years (2.5–16.3, ±3.6). Exeter V40 stem fracture incidence was 0.27%. Incidence was significantly higher in 125 mm length stems compared to ≥150 mm length stems (1.26% vs 0.13%, respectively, p <0.001) and revision arthroplasty (1.209% vs 0.149%, p <0.001). When comparing different stem length cohorts, 125-mm short-stem were associated with stem body fractures (92% vs 29%, p = 0.0095), earlier time to fracture (6.2 vs 11.0 years, p = 0.0018), younger patient age at time of fracture (62.7 vs 72.6 years old, p = 0.037) and female sex (75% vs 43%, p = 0.33).

This case series in conjunction with the systematic review provides evidence stem morphology plays a role in femoral implant fracture. This complication remains rare, although we report a significantly higher incidence at up to 17 years follow-up than in the literature. As femoral geometries remain the same, increasing BMIs in THR patients should raise concern. 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 meticulous surgical technique and planning.

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.

Introduction

The biological pathways responsible for adverse reactions to metal debris (ARMD) are unknown. Necrotic and inflammatory changes in response to Co-Cr nanoparticles in periprosthetic tissues may involve both a cytotoxic response and a type IV delayed hypersensitivity response.

Our aim was to establish whether differences in biological cascade activation exists in tissues of patients with end-stage OA compared to those with aseptic loosening of a metal on polyethylene (MoP) THR and those with ARMD from metal-on-metal (MoM) THR.

Summary

We report the first use of synchrotron xray spectroscopy to characterize and compare the chemical form and distribution of metals found in tissues surrounding patients with metal-on-metal hip replacements that failed with (Ultima hips) or without (current generation, large diameter hips) corrosion.

Introduction

Preoperative psychological distress has been reported to predict poor outcome and patient dissatisfaction after total hip replacement (THR). We investigated this relationship in a prospective multi-centre study between January 1999 and January 2002.

Introduction: We investigated the relationship between psychological distress and outcome after total hip replacement (THR) in the Exeter Primary Outcome Study (EPOS).

Materials & Methods: Data were collected from a number of centres across England between January 1999 and January 2002 for patients undergoing primary hip replacement using the cemented Exeter femoral component (Stryker). We recorded the Oxford Hip Score (OHS) for physical function and SF36 questionnaire for both physical and mental domain assessment annually for five years. We dichotomised the patients into the mentally distressed (MHS < 50) and the not mentally distressed (MHS ≥ 50) groups based on their pre-operative Mental Health Score (MHS) from the SF36 score.

Results: Complete data were available for 455 (407 not distressed and 48 distressed) patients. Pre-operative OHS and SF-36 score was significantly worse in the distressed group (both p< 0.001). Mean OHS improved from 43 to 20 at 1 year after surgery and remained the same thereafter in the non distressed group. In the mentally distressed group pre-operative mean OHS of 48 improved to 22 at 1 year after surgery. Maximum improvement in OHS occurred in the 1st yr after surgery. Mean MHS improved from 76 to 81 at 1 year after surgery and remained the same thereafter in the non distressed group. Mean MHS improved from 35 to 62 at 1 year after surgery, reaching 65 at 5 years after surgery in the mentally distressed group. The maximum improvement in MHS occurred in the 1st yr after surgery.

Conclusion: Pre-operative psychological distress did not compromise functional outcome after hip arthroplasty. There was a substantial improvement in mental distress in patients with mental distress prior to surgery. Both groups of patients experienced improvement in Oxford Hip Score, which was maximal by 1 year after surgery and was maintained over the 5 year follow up.

Introduction: As candidates for arthroplasty become younger and life expectancy increases the required working life of a total hip arthroplasty continues to rise. Hip resurfacing offers potential further advantages in young patients as minimal bone resection makes for easier revision, and the design allows for an increased range of movement. The Birmingham Hip Resurfacing (BHR) is the first of the second generation hip resurfacings.

Reports are beginning to emerge of unexplained failure, pseudotumour formation, individual cases of metallosis. Joint registry data also demonstrates an unexplained high early failure rate for all designs of hip resurfacing. This paper examines the rate and mode of early failures of the BHR in a multi-centre, multi-surgeon series.

Methods: All patients undergoing BHRs in our two centres were recruited prospectively into our arthroplasty follow up programme. Patients have been followed up radiographically and with clinical scores.

Results: Mean radiographic and clinical follow up was to 43 months (range 6 – 90 months). Of the 463 BHRs two have died and three are lost to follow up. Thirteen arthroplasties (2.8%) have been revised. Eight for pain, three for fracture, two for dislocation and one for sepsis. Of these nine were found to have macroscopic and histological evidence of metalloisis. Survival analysis at 5 years is 95.8% (CI 94.1 – 96.8%) for revisions and 96.9% (CI 95.5 – 98.3%) for metallosis.

Discussion: Histopathological examination demonstrated a range of inflammatory changes including necrosis, inflammation, ALVAL and metal containing macrophages. Not all features were associated with each patient and it is likely that these features form part of the spectrum of metal wear debris disease.

The likely rate of metallosis is 3.1% at five years. Risk factors for metallosis in this series are female sex, small femoral component, high abduction angle and obesity. We not advocate use of the BHR in patients with these risk factors.

A series of sixteen patients, 14 males and 2 females with an average age of 50 years (28–93) underwent total hip replacement surgery after acetabular fracture. Thirteen patients had previously undergone internal fixation of their acute fractures. Hip replacement surgery was performed by a single surgeon over an eight year period at an average of 30.36 (range 3–84) months after injury. Cases include high energy injuries as well as low energy fractures of the elderly (2 patients).

These were complex procedures due in some cases to the dramatic femoral head and acetabular bone stock loss when avascular necrosis had occurred following internal fixation. The use of acetabular mesh, allograft and reinforcement rings is discussed.

At the time of reporting the total hip replacements in this group of relatively young patients continue to be highly successful. One hip has been revised for recurrent dislocation.

This paper describes important surgical tips for the management of these complex cases. Removal of exposed metal work can be difficult. A role for MRI scanning in the early postoperative care following fracture fixation is postulated. The importance of early liaison of fracture fixation surgeons with arthroplasty colleagues leads to earlier surgery with reduction of bone stock loss.

There has been controversy about the practice of mixing femoral and acetabular implants from different manufacturers in total hip replacement (THR). We studied the clinical outcomes of over 1500 patients in the Exeter Primary Outcomes Study (EPOS) who underwent primary THR with a cemented Exeter stem (Stryker) but with various acetabular components. This was a prospective non-randomised multicentre study. Patient reported hip scores (Oxford Hip Score (OHS)) were measured before operation and at 1 and 2 years post operatively. The choice of acetabular implant was at the surgeons’ discretion. 982 patients had reached four year follow up. Six types of acetabular component were examined (Exeter, Exeter Contemporary, Duraloc (all Stryker), Charnley (DePuy), Cenator (Corin), and Trilogy (Zimmer)).

Patients who received a Charnley cup were found to have worse pre-operative status (significantly higher OHS) than those receiving other cups (especially those receiving Exeter cups) (p< 0.01). Post operatively, this difference continued, with the absolute OHS value remaining greater (i.e. worse clinical result) for the Charnley cup at 1, 2, 3 and 4 years. The association of poor pre-op status with worse post-op result was anticipated. However, when the clinical benefit of surgery (i.e. the improvement in OHS between pre-op and post-op) was assessed, there was no significant difference between the various implants at 1, 2, 3 and 4 years.

These results demonstrate that initial clinical benefit of surgery does not differ between patients receiving acetabular implants from varying manufacturers when the Exeter stem is used. These patients will be followed further to determine whether such “mixing and matching” results in differences in longer term outcomes.

The optimal surgical approach for total hip replacement (THR) remains controversial. We report the clinical outcomes of over 1000 patients in the Exeter primary outcomes study (epos) who underwent primary THR with a cemented Exeter stem (Stryker) but with various acetabular components. This was a prospective non randomised multi centre study. Patient reported hip scores (oxford hip score (OHS)) were measured before operation and at 3 months (n= 1312), 1 (n=1276), 2 (n= 1225), 3 (n=1205) and 4 (n=975) years post operatively. Physician reported scores (Merle d’Aubigne / Postel, MDAP) were measured before operation and at 12 months. All of the operations were carried out using either the anterolateral (Hardinge or modification) or posterior approach.

The posterior approach gave better absolute OHS scores at 3 months and 1 year compared with the anterolateral approach. The improvement in OHS between the pre-op and relevant post-op score was better for the posterior than the Hardinge approach, and this extended to 4 years (all p< 0.05). Early dislocation rates were low in both groups. There was significantly more likely to be heterotopic ossification in the Hardinge group, while stem alignment into varus was more common in the posterior approach group. There was no significant difference between the two approaches as measured using the MDAP score at pre-op or at 12 months after surgery.

These results demonstrate that initial patient perceived clinical benefit of surgery is greater using a posterior than with an anterolateral approach. This should be considered when assessing the best approach for a particular patient. The current results emphasise the value of using patient based outcome measures, as the MDAP score did not detect a difference in outcomes between the two groups.

There has been controversy about whether limb length discrepancy (LLD) affects outcome after total hip replacement (THR). We examined input variables and outcomes of over 1200 patients who received primary THR with the Exeter stem and a variety of acetabular components in the Exeter Primary Outcomes Study. This was a non randomized prospective multi centre study.

We examined whether specific groups of patients or surgeons were more likely to have LLD at one year after surgery. Data for leg length measured on clinical assessment were available for 1207 patients at 1 year. 237 patients were recorded as having a leg length difference of 1 cm or more, and 73 a difference of 2 cm or more. 138 were longer on the operated side and 99 were shorter. The likelihood of having LLD of 2 cm or more was not significantly affected by the grade of surgeon (consultant or trainee), BMI, age of patient, position of patient during surgery or surgical approach, or the use of regional or general anaesthetic.

We examined the effect of LLD on outcomes at 3 months and 1,2,3 and 4 years. Patients with LLD > 1cm had significantly worse Oxford Hip Scores (OHS) at 1, 2, 3 and 4 years (p< 0.01), with the OHS generally being an average 2 points worse in those with LLD. The most consistent difference between those with and without LLD was a patient reported limp on the Oxford Hip Questionnaire.

We conclude that LLD is a common problem after THR and that all patient groups may be affected. It is associated with a significantly worse functional outcome as measured by a validated hip score. Systematic adoption of accurate intra-operative measures of leg length might pay dividends in minimizing this complication.

There is concern that patients undergoing total hip replacement by trainee surgeons may do worse than those operated on by consultants. We examined the clinical outcomes of over patients in the Exeter Primary Outcomes Study who underwent primary THR with a cemented Exeter stem (Stryker) with various acetabular components. Over 1400 patients entered the prospective non-randomised multi centre study. Patient reported hip scores (Oxford Hip Score (OHS)) were measured pre operation and at 3 months, 1,2,3 and 4 years post operatively.

The number of patients assessed at 4 years was 982. Trainees operated on patients with worse pre-operative OHS (p< 0.05; t test)) and on significantly less patients under 60 years (p< 0.05 chi square). There was no significant difference in the improvement in OHS (i.e. pre-op OHS – post-op OHS) at any post-operative time point between consultants and trainees. However, patients operated upon by consultants had consistently better postoperative absolute OHS scores (p< 0.05 at 3 months and 1, 2, 3 and 4 years; t test). Complications were low in both groups. Operations performed by trainees lasted longer (mean of 104 vs. 85 minutes). There was also no difference in OHS scores of patients operated by trainees whether they were assisted by an SHO (n=132) or by a consultant (n=249).

In this large cohort of patients there was no difference in the improvement in OHS between patients operated by registrars and consultants. The difference in the absolute OHS values is likely explained by the difference in pre-operative status. We conclude that THRs performed by consultants and by trainees under appropriate supervision give similar initial clinical results. Given current changes to shorten surgical training, it is important that outcomes of THRs performed by future trainees are reviewed to ensure that outcomes are maintained.

This prospective study evaluates the outcome of a new metal -on-metal total hip replacement in a younger group of patients.

Fifty-five primary all-metal total hip replacements (THR) were evaluated prospectively at a follow-up of 2.8–5.5 years. Patients were selected according to age and activity levels. The mean age was 58 years (41–69). 33 males and 22 females were included in the study. Surgery was carried out for osteoarthritis in 52 patients and for non-union fractured femoral neck, ankylosing spondilitis and post slipped upper femoral epiphysis in the three remaining patients. A single surgeon (the senior author) through the posterior approach carried out the surgery. All patients received the porous coated titanium shell with a Morse taper cobalt chrome liner and double wedge tapered polished cobalt chrome stem and modular head. Blood metal ion analysis was performed on a cohort of 24 patients using High Resolution Inductively Coupled Plasma Mass Spectrometry, sampling taken preoperatively and then repeated post operatively at 6 months, 1 year and then annually.

Clinical results have been excellent. X rays show Harris A cementation in all femurs, with no component migration or radiolucencies being identified on follow-up radiographs. No prosthesis to-date has required revision. One patient has died and one is lost to follow up. The following non-device related complications were reported in the group, 2 (4%) superficial wound infections, 1 (2%) dislocation, 1 (2%) thrombosis, 1 (2%) IT band defect and 2 (4%) impingement. The dislocation was treated with a closed reduction. The impingement has resolved by one year in both patients. The results of the pre and postoperative blood metal ion analysis demonstrate some elevated levels, these levels being similar to those previously reported in the literature.

The hybrid all-metal THR may represent a valuable alternative in the younger, high demand patient.

During arthroplasty acetabular deficiencies could be reconstructed using different techniques. We describe our early results of acetabular reconstruction using impaction bone grafting supported by a wire mesh.

This is a retrospective review of 45 patients (46 hips, 1 bilateral) who had acetabular reconstruction with impaction bone grafting and wire mesh between 1995–1999. The average follow up was 36 months (18–54 months). Mean age at operation was 70 years (41–88 years). 28 were primary (osteoarthritis) and 18 were revisions (painful aseptic loosening). Paprowsky’s classification was used to grade the defects – 44 hips: grade II, 2 hips: type III A. Containment was achieved with a wire mesh anchored with screws. The defect was filled with morcellised bone graft, which was impacted under the mesh (autograft in primary and allograft in revisions). Cemented Exeter components were used. Merle d’Aubigné Postel hip score and AAOS proforma was used during follow-up and cup migration was assessed using Nunn and Freeman’s method.

Merle d’Aubigné Postel score showed improvement of at least 10 points in each patient (Charnley prefix: type A – 27 patients; type B – 10 patients; Type C – 8 patients) Mean vertical and horizontal cup migration of 2.6 mm each was seen, which was not statistically significant (at 5% level). Graft incorporation was seen in all radiographs. 32 hips showed a thin sheet of new bone over the superolateral surface of the mesh which was regarded as a sign of good graft incorporation. There were no complications specifically related to the wire mesh or screws (1 – superficial wound infection, 2-DVT, 2- dislocations treated conservatively). None of the patients required further revision surgery.

We are encouraged by our early results of this method for reconstruction of peripheral acetabular rim deficiencies because it restores anatomy, biomechanics, replaces bone loss and provide a stable construct.

Fifty five primary Ultima® hybrid all-metal (Johnson & Johnson Professional DePuy) total hip replacements (THR) were evaluated prospectively at a mean follow up of 24 months. Patients were selected according to age and activity levels. The mean age at surgery was 58 years (41–69 years). 33 males and 22 females were included in the study. Surgery was carried out for osteoarthritis in 52 patients and for non-union fractured neck of femur, ankylosing spondilitis and post slipped upper femoral epiphysis in the three remaining patients. A single surgeon (the senior author) through the posterior approach carried out surgery. All patients received the Ultima® porous coated titanium shell with a morse taper cobalt chrome liner and double wedge taper polished stem and modular head. Blood metal ion analysis was performed on a cohort of 24 patients using High Resolution Inductively Coupled Plasma Mass Spectrometry, sampling taken pre operatively and then repeated post operatively at 6 months, 1 year and then annually.

Clinical results reported at a mean follow-up interval of 2.016 years have been excellent, with no prosthesis to-date requiring revision and no component migration or radiolucuencies being identified on any follow-up radiographs. One patient has died and one is lost to follow-up. The following non-device related complications were reported in the group, 2 (4%) superficial wound infections, 1 (2%) dislocation, 1 (2%) thrombosis, 1 (2%) IT band defect and 2 (4%) impingement. The dislocation was treated with a closed reduction, the position of the component having been judged as satisfactory. The impingement has resolved by one year in both patients. The results of pre and postoperative blood metal ion analysis in a cohort of 24 patients demonstrate some elevated levels, these levels are similar to those previously reported in the literature.

The Ultima® hybrid all-metal THR may represent a valuable alternative in the younger, high demand patient.