Introduction: Between 1990 and 2000 we reconstructed 123 hips in 110 patients using impaction bone grafting with frozen, morsellised irradiated femoral heads and cemented sockets. This review presents the medium to long term survivorship of irradiated allograft in acetabular reconstruction in our cohort of patients.

Patients and Methods: Patients were reviewed in out-patients. Radiographs were examined for union, lucency and component migration.

The mean age at revision with allograft was 64.3 years (26 to 97). 86 hips (70%) in 74 patients were reviewed both clinically and radiologically.

At the time of review 28 patients (29 hips) had died and 5 patients (5 hips) were lost to follow up. Of those patients who had died 18 hips had been followed up to a mean of 66 months (12–145). A further 3 hips were unable to attend for clinical review but had accurate implant-allograft survivorship data.

Their data were included in survivorship analysis to the time of last clinical review.

Results: There have been 19 revisions; 9 for infection, 7 for aseptic loosening and 3 for dislocation. In surviving acetabular reconstructions, union of the graft had occurred in 64 out of 67 hips (95.5%). Radiolucent lines at the bone cement interface were seen in 12 hips (17.9%; 9 in a single DeLee zone and 3 in multiple zones) but none were considered loose. Migration of the acetabular component greater than 5mm was seen in 3 hips (4.5%). Survivorship analysis using revision as an end point for all indications at 10 years was 83.3% (95% C.I. 68 to 89%) and 71.3% (95% C.I. 58 to 84%) at 15 years

Conclusion: Acetabular reconstruction using irradiated allograft and a cemented cup is an effective reliable technique with good results in the medium to long term comparable to series using non irradiated freshly frozen bone.

Between 1988 and 1998 we implanted 318 total hip replacements (THRs) in 287 patients using the Plasmacup (B. Braun Ltd, Sheffield, United Kingdom) and a conventional metal-on-polyethylene articulation. The main indications for THR were primary or secondary osteoarthritis.

At follow-up after a mean 11.6 years (7.6 to 18.4) 17 patients had died and 20 could not be traced leaving a final series of 280 THRs in 250 patients. There were 62 revisions (22.1%) in 59 patients. A total of 43 acetabular shells (15.4%) had been revised and 13 (4.6%) had undergone exchange of the liner. The most frequent indications for revision were osteolysis and aseptic loosening, followed by polyethylene wear. The mean Kaplan-Meier survival of the Plasmacup was 91% at ten years and 58% at 14 years. Osteolysis was found around 36 (17.1%) of the 211 surviving shells. The median annual rate of linear wear in the surviving shells was 0.12 mm/year and 0.25 mm/year in those which had been revised (p < 0.001). Polyethylene wear was a strong independent risk factor for osteolysis and aseptic loosening. The percentage of patients with osteolysis increased proportionately with each quintile of wear-rate.

There is a high late rate of failure of the Plasmacup. Patients with the combination of this prosthesis and bearing should be closely monitored after ten years.

Between 1990 and 2000, 123 hips in 110 patients were reconstructed for aseptic loosening using impaction bone grafting with frozen, irradiated, morsellised femoral heads and cemented acetabular components. This series was reported previously at a mean follow-up of five years. We have extended this follow-up and now describe the outcome of 86 hips in 74 patients at a mean of ten years. There have been 19 revisions, comprising nine for infection, seven for aseptic loosening and three for dislocation. In surviving acetabular reconstructions, union of the graft had occurred in 64 of 67 hips (95.5%).

Survival analysis for all indications at ten years was 83.3% (95% confidence interval (CI) 68 to 89) and 71.3% (95% CI 58 to 84) at 15 years.

Acetabular reconstruction using irradiated allograft and a cemented acetabular component is an effective method of reconstruction, providing results in the medium- to long-term comparable with those of reported series where non-irradiated freshly-frozen bone was used.

Introduction: Between 1987 and 1997 we implanted 319 primary hybrid total hip arthroplasties in 289 patients using the ‘Plasmacup’ (B. Braun Ltd, Sheffield) with a conventional metal on polyethylene articulation. We have observed a high revision rate with this implant recently and therefore undertook a clinical review of this cohort.

Patients and Methods: The indications for surgery were osteoarthritis (223), secondary arthritis (83), inflammatory arthritis (10), and others (3). 17 patients have died and 20 have been lost to follow up. Survival analysis was calculated using implant failure defined as revision (including liner exchange), and includes the censored patients outlined above. Assessment of complications in surviving implants was made using AP radiographs of the hip.

Results: The cup survival rate (Kaplan-Meier method) was 91% at 10 years (95%CI ± 4%) and 67% at 13 years (95%CI +/−9%). The stem survival rate was 96% at 10 years (95%CI +/−3%) and 87% at 13 years (95%CI +/−7%). The median wear in cup revisions for osteolysis was 2.4mm (IQR 1.0–3.2mm), and the median wear in surviving cups was 1.3 mm (IQR 0.8 1.9mm), and was an independent predictor of failure (Cox: p=0.001). There have been 57 revisions (35 cup only, 18 cup and stem, 4 stem only). Indications for revision were osteolysis or loosening (34), wear (18), and infection (5). In surviving cups (214), 29 have expansile acetabular osteolysis and 8 have linear osteolysis. In surviving stems (244), 14 have expansile osteolysis and 23 have linear osteolysis.

Conclusions: There is a high late failure rate of the plasma cup using a conventional metal on polyethylene articulation. Patients with this implant/bearing combination should be closely monitored, particularly after 10 years.

Introduction: The use of prolonged courses of parenteral or oral antibiotic therapy in combination with a two-stage exchange procedure in the management of the infected total hip arthroplasty is reported by many major series.

Methods: We present a series of 114 patients, all with microbiologically proven chronic deep infection, treated with a two-stage exchange with antibiotic loaded cement and where a prolonged course of antibiotic therapy has not been used. The mean follow-up for all patients is 74months (range 2–175months) with all surviving patients having a minimum 2 year follow-up.

Results: Infection was successfully eradicated in 100 patients (88%). The infection cure rate in our series is similar to that reported elsewhere where prolonged adjuvant antibiotic therapy was used.

Discussion: Using the technique described a prolonged course of systemic antibiotics does not appear to be necessary; the high costs of antibiotic administration, both to the patient and care facility are not incurred.

Introduction: There are few published reports outlining the outcome of those patients who have undergone revision hip arthroplasty surgery for recurrent infection.

From a consecutive series of 114 patients who had undergone a two-stage exchange without prolonged antibiotic therapy we report the outcome of those patients who continued to have persistent infection.

Methods: Fourteen patients were identified, all with microbiologically proven recurrent deep infection. Seven patients have undertaken further attempts at cure by a two-stage exchange and where again a prolonged course of antibiotic therapy was not routinely used. Infection was eradicated in six out of the seven patients (84%). The mean follow-up of this group is 90 months (range 25–150 months).

Results: From the initial series an overall cure rate of 93% was seen. The other patient has a pseudarthrosis.

Seven patients elected not to undergo a further two-stage revision. Five patients have retained their arthroplasty with lifelong suppressive antibiotic therapy. One has a pseudarthrosis and one disarticulation has taken place for inadequate tissue cover.

Discussion: This series would suggest that in patients willing to undertake further surgery in an attempt to eradicate infection they stand a good chance of a successful outcome.

Introduction: The concept that aseptic loosening is a function of polyethylene wear has led to the introduction of cross-linked polyethylene in THA. We studied the relationship between polyethylene wear rate and aseptic loosening to model the potential effects of wear-reducing strategies on the failure rate for each prosthetic component.

Methods: 350 subjects who had previously undergone Charnley THA were divided into 3 groups: Controls (n=273); isolated femoral stem looseners (n=43); and isolated cup looseners (n=34). Polyethylene wear was measured using a validated method (EBRA). The relationship between wear rate and loosening was examined using logistic regression analysis, and estimates of the effect of wear rate modulation made using odds-ratios (OR ).

Results: The median annual wear rate in the controls (0.07mm) was lower than both stem looseners (0.09mm, p=0.002) and cup looseners (0.18mm, p< 0.001). The OR of cup loosening increased 4.7 times per standard deviation (SD) increase in wear rate above the reference (control) population (p< 0.001). The OR of stem loosening increased 1.7 times per SD, but was not independent of other risk factors (p> 0.05). The potential reduction in risk of loosening was calculated using the following formula: (OR ^SD2)/(OR ^SD1), where 1 and 2 are the predicted mean z-score wear rates of modified versus conventional polyethylene. Thus, for a 25% or 50% reduction in wear rate, the incidence of cup loosening may reduce by 71% and 293%, respectively. The rate of stem loosening may reduce by 7% and 17%, respectively.

Discussion: The use of cross-linked-polyethylene has the potential for a major impact on the incidence of cemented cup loosening. However their effect on femoral stem loosening may be limited.

Introduction: Bone phenotype, such as osteoarthritis (OA) pattern and development of osteolysis or heterotopic ossification (HO) after THA, may be governed by genetic and environmental factors. We investigated whether single nucleotide polymorphisms within the gene encoding secreted-Frizzled Related Protein-3, FRZB Arg200Trp and FRZB Arg324Gly influence bone phenotype.

Methods: Genomic DNA was extracted from 609 subjects at a mean of 11 years following cemented THA for idiopathic osteoarthritis. Pre-operative OA was defined using The American College of Rheumatology criteria and post operative HO after primary THA was assessed using Brooker’s classification

Results: For FRZB Arg200Trp, minor allele carriage (MAC) was greater in subjects with pre-operative pelvic osteophytes (n=267) versus those without osteophytes (n=34) (MAC 27.9% versus 6.3%, Fisher’s exact test p=0.037). There were no associations with other radiographic criteria of OA. MAC was also higher in HO+ve subjects (n=291) versus HO-ve subjects (n=341), (MAC 21.7% versus 12.0%, χ² test p=0.063). Finally MAC was 14.2% in osteolysis +ve subjects (n=268) and 21.7% in osteolysis –ve subjects (n=341) (χ² test p=0.041).

The adjusted odds ratios for pelvic osteophytes and HO with carriage of the rare FRZB 200 variant were 4.34 (1.01–18.7 p=0.048) and 1.64 (1.05 to 2.54, p=0.028) respectively. The adjusted odds ratio for osteolysis was 0.62 (0.38 to 0.99 p=0.049).

There were no bone phenotype associations with the FRZB Arg324Gly variants.

Discussion: Carriage of the FRZB 200Trp allele is positively associated with osteophyte and HO formation and negatively associated with osteolysis, suggesting this locus may be a marker for pro-osteoblastic activity.

Introduction: Bone cements produced by different manufacturers vary in their mechanical properties and antibiotic elution characteristics. Small changes in the formulation of a bone cement, which may not be apparent to surgeons, may also affect these properties. The manufacturing method of Palacos bone cement with added gentamicin has recently changed. We have carried out a study to examine the mechanical characteristics and antibiotic elution of Schering-Plough Palacos (‘old’ version), Heraeus Palacos (‘new’ version) and Depuy CMW Smartset bone cements.

Methods: Schering-Plough Palacos R40G (contains 0.5g gentamicin per 40g mix), Heraeus Palacos R+G (contains 0.5g gentamicin per 40g mix) and Depuy-CMW Smartset GHV (contains 1g gentamicin per 40g mix) were used. 40g samples of the three cements with no additional vancomycin, 1g and 2g vancomycin were prepared by a standard method using vacuum mixing in a syringe. Antibiotic elution over a five week period was measured using an immunoassay method. Standard mechanical testing was carried out according to methods defined in ISO 5833.

Results: Both Heraeus Palacos and Smartset bone cements performed significantly better than Schering-Plough Palacos in terms of mechanical characteristics both with and without additional antibiotics. All cements show a deterioration in flexural strength with increasing addition of vancomycin although staying above ISO minimum levels. Both Heraeus Palacos and Smartset elute significantly more gentamicin cumulatively than Schering-Plough Palacos. Smartset elutes significantly more vancomycin cumulatively compared with Heraeus Palacos.

Discussion: Both Heraeus Palacos and Smartset Bone cements elute significantly more gentamicin than Schering-Plough Palacos with no deterioration in mechanical characteristics. Smartset also elutes significantly more vancomycin than Heraeus Palacos without adverse affect on mechanical characteristics. Although marketed as the ‘original’ Palacos, Heraeus Palacos has significantly altered mechanical and antibiotic elution characteristics compared with previous versions.

Aims: Dislocation is one of the commonest complications following total hip arthroplasty. A significant proportion of these patients go on to have recurrent dislocations. Many factors have been identified as contributing to the risk of dislocation but treatment of recurrent dislocation is challenging. The use of semicaptive acetabular components is a potential solution to the problem of recurrent dislocation but there are few studies into the efficacy of these implants.

Methods: Patients who underwent revision of their total hip arthroplasty to a semi-captive socket at the Lower Limb Arthroplasty Unit, Northern General Hospital, Sheffield between 2001 and March 2006 were studied. A proforma was designed and data was obtained from patients’ medical records. The number of dislocations both prior to revision to a semi-captive component and the following revision to a semi-captive acetabular component were recorded including the method of reduction Reasons for revision and the number and reasons for previous revisions were noted.

Results: Average time of follow up was 22 months (range 2 months – 5 years 1 month). Following revision of total hip arthroplasty to a semi-captive component, 78% suffered no further dislocations. Of those patients who went on to redislocate, three went on to have recurrent dislocations and all were reduced by closed reduction. One patient redislocated and underwent a second revision to a semi-captive acetabular component, which was successful and underwent no further dislocations.

Discussion. The results of this study show the use of semicaptive acetabular components in revision surgery for dislocation following total hip arthroplasty to be a highly effective solution to the problem of recurrent dislocation.

Introduction: Aseptic loosening due to periprosthetic osteolysis is the main cause of implant failure after total hip arthroplasty (THA). Some previous studies have suggested a link between pattern of pre-operative osteoarthritis (OA) and subsequent aseptic loosening. Specifically, atrophic OA may predict implant loosening^1,2 however this remains controversial.³

Methods: We retrospectively assessed the survival of 301 cemented THAs inserted for idiopathic osteoarthritis to determine whether pre-operative patterns of osteoarthritis predict subsequent risk of osteolysis. There were 204 control subjects and 97 subjects with osteolysis. The mean age of patients at insertion of primary implant was 63.4 years and lysis free survival or follow up was 10.6 years. The osteoblastic response in OA was assessed using Bombelli’s classification. The American College of Rheumatology criteria for radiographic evidence of OA was used to assess the pattern of OA prior to primary THA

Results: Atrophic OA was not a risk factor for osteolysis. Atrophic OA in osteolysis group was 16% versus 14% in the control group (χ² test p> 0.05). There was no association between osteolysis and joint space narrowing, femoral or pelvic osteophytes, femoral or pelvic sclerosis, femoral or pelvic cysts and femoral head collapse (χ² test p> 0.05 all comparisons).

Conclusion: The morphological pattern of OA does not predict osteolysis after THA

Introduction: The concept that aseptic loosening is a function of polyethylene wear has led to the use of cross-linked polyethylene in total hip arthroplasty (THA). We studied the relationship between polyethylene wear rate and aseptic loosening in order to model the potential effects of wear-reducing strategies on the failure rate for each prosthetic component.

Methods: 350 subjects who had previously undergone Charnley THA were divided into 3 groups: Controls (n=273); those with loosening of only the femoral stem (n=43); and those with only cup loosening (n=34). Poly-ethylene wear was measured using a validated method (EBRA). The relationship between wear rate and loosening was examined using logistic regression analysis, and estimates of the effect of wear rate modulation made using odds-ratios.

Results: The median annual wear rate in the controls (0.07mm) was lower than both stem looseners (0.09mm, p=0.002) and cup looseners (0.18mm, p< 0.001). The odds of cup loosening increased 4.7 times per standard deviation (SD) increase in wear rate above the reference (control) population (p< 0.001). The odds of stem loosening increased 1.7 times per SD, but was not independent of other risk factors (p> 0.05). The potential reduction in risk of loosening was calculated using the following formula: (OR^SD2)/(OR^SD1), where 1 and 2 are the new and old mean z-score wear rates. Thus, for a 25% or 50% reduction in wear rate, the incidence of cup loosening may reduce by 71% and 293%, respectively. The rate of stem loosening may, at best, reduce by 7% and 17%, respectively.

Discussion: Wear reduction strategies, such as cross-linked polyethylene, have the potential for a major impact on the incidence of cemented cup, but not stem, loosening.

Introduction: It is common practice to use additional antibiotics in bone cement for revision hip surgery. Ideally antibiotic elution would initially be rapid and then reduce to zero in order to reduce the risk of antibiotic resistance developing. There is evidence that the addition of antibiotics to bone cement leads to deterioration in mechanical properties. We have carried out a study to see if the addition of vancomycin to Palacos R40G and Smartset GHV affects their in-vitro antibiotic elution and mechanical properties.

Methods: Palacos R40G (contains 0.5g gentamycin per 40g mix) and Smartset GHV (contains 1g gentamycin per 40g mix) were used. 40g samples of the two cements with no additional vancomycin, 1g and 2g vancomycin were prepared by a standard method using vacuum mixing in a syringe. Antibiotic elution over a five week period was measured using an immunoassay method. Standard mechanical testing was carried out according to methods defined in ISO 5833.

Results: Smartset GHV eluted double the quantity of gentamycin as Palacos R40G, as would be expected. Both cements eluted more gentamycin when vancomycin was added. Smartset appears to elute more vancomycin than Palacos initially and then shows a more rapid tailing off. The mechanical properties of the two cements were the same with no statistical differences found between them. Both showed deterioration in flexural strength with addition of increasing vancomycin.

Discussion: Smartset may have improved qualities of antibiotic elution as compared with Palacos with similar mechanical properties. The presence of higher initial quantities of gentamycin does not lead to reduced mechanical properties.

Introduction: The correct identification of the infecting micro-organism in prosthetic joint infections is difficult and there is no single method that is wholly reliable. We report a novel method intended to improve accuracy by disrupting the biofilm surrounding the prosthesis and transferring samples rapidly to culture medium.

Method: Explanted prostheses from 20 revision operations were sampled by pressing a microbiology swab or by passing a No.10 surgical blade along it. The sample so obtained was plated immediately in the operating theatre onto horse-agar petri dishes. These were incubated in aerobic conditions in the laboratory. Culture results were compared with those obtained from our standard detection method using multiple tissue samples with are plated or grown in prolonged aerobic and anaerobic culture broth.

Results: The method proved practical to perform in practice. When compared with multiple tissue samples as the standard, the Positive Predictive Value was 90%, Negative Predictive Value 80%, sensitivity 82%, specificity 89%. In 4 of the 10 true positive samples, the theatre-inoculated samples yielded early results within 3 days, while conventional method yielded positives only later on prolonged culture.

Discussion: The above pilot is to continue and has started to alter our practice in sample taking. Blade-scrape does appear to penetrate the biofilm successfully. Growing confidence in interpretation and ease in reading the plates mean that in certain cases, we consider the results to be more reliable than traditional tissue culture. Direct plating also reduces the chance of bacterial overgrowth in broth inhibiting colonies of secondary infective organisms. Further refinement is needed, particularly with regard to anaerobic bacteria. Inaccuracies have resulted when agar plates are allowed to go out of date.

Introduction: Activated peri-prosthetic macrophages release pro-inflammatory cytokines, including interleukin-6 (IL-6), that stimulate osteoclast activation and aseptic loosening. Natural sequence variations (polymorphisms) within the IL-6 gene promoter region are associated with diseases characterised by increased osteoclast activity, including osteoporosis, and affect IL-6 production in-vitro. We tested whether polymorphisms in the IL-6 gene promoter influence the risk of aseptic loosening after total hip arthroplasty (THA).

Methods: 614 Caucasians, 292 men and 322 women, mean age 75.8 years who had undergone primary cemented THA for idiopathic osteoarthritis a mean of 13.4 years previously were recruited. Peripheral blood was taken and DNA extracted using standard techniques. Subjects were genotyped for the IL-6 -174, -572, and -597 promoter single nucleotide polymorphisms using the Taqman 5′ nuclease method.

Results: The allele frequencies and carriage rates for both alleles at promoter positions −174, −572, and −597 were similar between controls and aseptic loosening subjects (Table, χ² P> 0.05 all comparisons).

Discussion: Although Il-6 has been implicated in the pathogenesis of aseptic loosening and the −174, −572, and −597 polymorphisms are associated with bone loosing pathologies, they do not appear to play a major role in aseptic loosening after THA.

Bone cements produced by different manufacturers vary in their mechanical properties and antibiotic elution characteristics. Small changes in the formulation of a bone cement, which may not be apparent to surgeons, can also affect these properties. The supplier of Palacos bone cement with added gentamicin changed in 2005. We carried out a study to examine the mechanical characteristics and antibiotic elution of Schering-Plough Palacos, Heraeus Palacos and Depuy CMW Smartset bone cements.

Both Heraeus Palacos and Smartset bone cements performed significantly better than Schering-Plough Palacos in terms of mechanical characteristics, with and without additional vancomycin (p < 0.001). All cements show a deterioration in flexural strength with increasing addition of vancomycin, albeit staying above ISO minimum levels. Both Heraeus Palacos and Smartset elute significantly more gentamicin cumulatively than Schering-Plough Palacos. Smartset elutes significantly more vancomycin cumulatively than Heraeus Palacos.

The improved antibiotic elution characteristics of Smartset and Heraeus Palacos are not associated with a deterioration in mechanical properties. Although marketed as the ‘original’ Palacos, Heraeus Palacos has significantly altered mechanical and antibiotic elution characteristics compared with the most commonly-used previous version.

Between 1980 and 2000, 63 support rings were used in the management of acetabular deficiency in a series of 60 patients, with a mean follow-up of 8.75 years (2 months to 23.8 years). There was a minimum five-year follow-up for successful reconstructions. The indication for revision surgery was aseptic loosening in 30 cases and infection in 33. All cases were Paprosky III defects; IIIA in 33 patients (52.4%) and IIIB in 30 (47.6%), including four with pelvic dissociation. A total of 26 patients (43.3%) have died since surgery, and 34 (56.7%) remain under clinical review. With acetabular revision for infection or aseptic loosening as the definition of failure, we report success in 53 (84%) of the reconstructions. A total of 12 failures (19%) required further surgery, four (6.3%) for aseptic loosening of the acetabular construct, six (9.5%) for recurrent infection and two (3.2%) for recurrent dislocation requiring captive components. Complications, seen in 11 patients (18.3%), included six femoral or sciatic neuropraxias which all resolved, one grade III heterotopic ossification, one on-table acetabular revision for instability, and three early post-operative dislocations managed by manipulation under anaesthesia, with no further instability.

We recommend support rings and morcellised bone graft for significant acetabular bone deficiency that cannot be reconstructed using mesh.

We present a series of 114 patients with microbiologically-proven chronically-infected total hip replacement, treated between 1991 and 2004 by a two-stage exchange procedure with antibiotic-loaded cement, but without the use of a prolonged course of antibiotic therapy. The mean follow-up for all patients was 74 months (2 to 175) with all surviving patients having a minimum follow-up of two years. Infection was successfully eradicated in 100 patients (87.7%), a rate which is similar to that reported by others, but where prolonged adjuvant antibiotic therapy has been used. Using the technique described, a prolonged course of systemic antibiotics does not appear to be essential and the high cost of the administration of antibiotics can be avoided.

We report a case of local compression-induced transient femoral nerve palsy in a 46-year-old man. He had previously undergone surgical release of the soft tissues anterior to both hip joints because of contractures following spinal injury. An MRI scan confirmed a synovial cyst originating from the left hip joint, lying adjacent to the femoral nerve. The cyst expanded on standing, causing a transient femoral nerve palsy. The symptoms resolved after excision of the cyst.

Bleeding is a major complication of revision total hip replacement. We report a case where the inflated balloon of a urinary catheter was used to temporarily control intrapelvic bleeding from the superior gluteal artery, while definitive measures for endovascular embolisation were made.