Aims

This study describes the variation in the annual volumes of revision hip arthroplasty (RHA) undertaken by consultant surgeons nationally, and the rate of accrual of RHA and corresponding primary hip arthroplasty (PHA) volume for new consultants entering practice.

Aims

The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS.

Aims

The aim of this modified Delphi process was to create a structured Revision Hip Complexity Classification (RHCC) which can be used as a tool to help direct multidisciplinary team (MDT) discussions of complex cases in local or regional revision networks.

Revision total hip arthroplasty (rTHA) can be complex and associated with significant cost, with an increasing burden within the UK and globally. Regional rTHA networks have been proposed aiming to improve outcomes, reduce re-revisions and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for the rTHA service and to assess the financial impact of case complexity at a tertiary referral centre within the NHS.

A retrospective analysis of all revision hip procedures was performed over two consecutive financial years (2018–2020). Cases were classified according to the Revision Hip Complexity Classification (RHCC) and by mode of failure; infected or non-infected. Patients of ASA grade of 3 or greater or BMI over 40 are considered “high-risk” by the RHCC. Costs were calculated using PLICS and remuneration based on the HRG data. The primary outcome was the financial difference between tariff and cost per episode per patient. Comparisons between groups were analysed using analysis of variance and two-tailed unpaired t-test.

199 revision episodes were identified in 168 patients: 25 (13%) least complex revisions (H1), 110 (55%) complex revisions (H2) and 64 (32%) most complex revisions (H3). 76 (38%) cases were due to infection. 78 (39%) of patients were in the “high-risk” group. Median length of stay increased with case complexity from 4, to 6 to 8 days (p=0.17) and significantly for revisions performed for infection (9 vs 5 days; p=0.01). Cost per episode increased significantly between complexity groups (p=0.0002) and for infected revisions (p=0.003). All groups demonstrated a mean deficit, but this significantly increased with revision complexity (£301, £1,820 and £4,757 per case; p=0.02) and for infected failure (£4,023 vs £1,679; p=0.02). The total deficit to the trust for the two-years was £512,202.

Current NHS reimbursement for rTHA is inadequate and should be more closely aligned to complexity. An increase in the most complex rTHA at major revision centres (MRC) will likely place a greater financial burden on these units.

Abstract

Introduction

Orthopaedic theatres can be noisy.

Noise exposure is known to be related to reduced cognition, reduced manual dexterity and increased rates of post-operative wound infection. Up to 50% of orthopaedic theatre staff have features of Noise-Induced Hearing Loss (NIHL) with higher levels in consultants compared to registrars. Exposure to noise levels of 90dB(A) at work for a career of 40 years, equates to a 51% risk of hearing loss.

Introduction

Data on the outcome of THA in patients under the age of 30 years is sparse. There is a perceived reluctance to offer surgery to young patients on the basis of potential early failure of the implant. We aim to review our experience with THA in this group of patients to establish outcomes in a high volume specialist arthroplasty unit.

Background

An extended trochanteric osteotomy (ETO) is a widely used approach for revision hip arthroplasty. Following an ETO it is common practice to use a long stemmed femoral prosthesis at the second stage to bypass the osteotomy. We propose that at the second stage, if the osteotomy has united, it is appropriate to use a standard length prosthesis, which preserves bone stock for any future revisions.

The use of a quadrupled hamstring graft in ACL reconstruction is well established. There are many described techniques in securing graft fixation, the optimal method is not yet established. The aim of this study was to review the results of a single surgeon series using the above implants looking at functional outcome for the patient and implant survivorship.

Patients were recruited for the study who had completed 8 months of post-op rehabilitation following primary ACL reconstruction and that had received the same surgical technique using the same implants from one surgical team. Patients undergoing a revision procedure were excluded. All patients received the same post-operative rehabilitation. Those who met the inclusion criteria were contacted via a postal survey using the Lysholm and Tegner questionnaires.

In total 77 patients were eligible for inclusion, consisting of 10 females and 67 males with a mean age of 31 (range 16-56). A 77% survey return rate was achieved with average follow up of 25 months (range 9-44). The mean Lysholm score was 82.1, with 59% ranking their knee as good or excellent. On average patients dropped 1.8 levels on the Tegner activity rating from a pre-injury average of 7.5 to post rehabilitation average of 5.7. There was a 100% survivorship of implants with no revisions undertaken due to implant failure.

The study has shown that this cohort of patients has produced self reported outcomes analogous to findings in the current literature. No obvious problem with implants was observed. It has highlighted the multiple factors associated with the outcome of ACL reconstruction and demonstrates that the quadrupled HT graft using Bio-Intrafix and Rigidfix implants produces short to mid-term functional and activity levels in keeping with the literature standard.

AIMS

To review the results of a single surgeon series using the above implants looking at functional outcome and implant survivorship.

The study aimed to determine how well recorded pain levels and range of motion relate to patients' reported levels of functional ability/disability pre- and post- total hip arthroplasty.

Range of motion (ROM), Oxford Hip Score (OHS) and Self-Report Harris Hip Score (HHS) were recorded pre-operatively and 3 months post-total hip arthroplasty. Pearson's correlation coefficients were calculated to determine the strength of the relationships both pre- and post-operatively between ROM (calculated using the HHS scoring system) and scores on OHS and HHS and response relating to pain from the questionnaires (question 1 HHS and questions 1, 6, 8, 10, 11 and 12 of OHS) and overall scores.

Only weak relationships were found between ROM and HHS pre- (r = 0.061, n = 99, p = 0.548) and post-operatively (r = 0.373, n = 66, p = 0.002). Similar results were found for OHS, and when ROM was substituted for flexion range. In contrast, strong correlations were found between OHS pain component and HHS pre- (r = -0.753, n = 107, p<0.001) and post-operatively (r = -0.836, n = 87, p<0.001). Strong correlations were also found between the OHS pain component correlated with the HHS functional component only (HHS with score for questions relating to pain deducted) pre- (r = -0.665, n = 107, p<0.001) and post-operatively (r = -0.688, n = 87, p<0.001). Similar results were found when the HHS pain component was correlated with OHS.

In orthopaedic clinical practice ROM is routinely used to assess the success or failure of arthroplasty surgery. These results suggest that this should not be done. Instead, asking the patient the level of pain that they are experiencing may be a good determinant of level of function. The results of this study may aid the development of arthroplasty scoring systems which better assess patients' functional ability.

To assess whether prosthetic femoral stem centralisers have a detrimental effect on the macroporosity of the cement mantle, and if so, whether this is independent of their design and the rate of implantation, 30 identically cast moulded prosthetic femora were divided into 3 groups. Group 1: no centraliser (control), Group 2: centraliser A and Group 3: centraliser B. Using third generation cementation techniques and pressure monitoring, Charnley C-stems +/− the appropriate centraliser were implanted to a constant depth. Half in each group were implanted as rapidly as possible and the other half over 90 seconds. The stems were removed and the cement mantle then underwent a preliminary arthroscopic examination prior to being sectioned transversely at 3 constant levels. Each level was then photographed and digitally enlarged to a known scale to allow examination and determination of any cement voids (macropores) surface area.

There were no significant pressure fluctuations between the groups. Preliminary arthroscopic examination revealed that cement voids appeared more common when a centraliser was used. This difference was confirmed (p=0.002) following sectioning of the specimens, with cement voids found in 85% of femora when a centraliser was used and only 20% in the control group. Centraliser B performed worst with cement voids of a larger volume and more frequent occurrence (p=0.002). The macroporosity of the cement mantle was independent of the rate of implantation (p=0.39).

The use of femoral stem centralisers is helpful in preventing malposition of the implant but results in increased macroporosity of the cement mantle. This may have implications regarding the longevity of an implant in terms of early loosening and therefore their design and use must always be carefully considered.

In this 2-year randomised clinical trial we examined whether cemented femoral prosthesis geometry affects the pattern of strain-adaptive bone remodelling in the proximal femur after THA. 128 patients undergoing primary THA were randomised to receive a Charnley (shape-closed, no taper), Exeter (force-closed, double-tapered) or C-stem (forced-closed, triple-tapered) prosthesis. All received a cemented Charnley cup. Proximal femoral BMD change over 2 years was measured by DXA. Urine and serum samples were collected at pre-operative baseline and over 1 year post-operatively. N-telopeptides of type-I-collagen (NTX) was measured in urine as a marker of osteoclast activity and Osteocalcin (OC) in serum as a maker of osteoblast activity. Clinical outcome using the Harris and Oxford hip scores, and prosthesis migration measured using digitised radiographs (EBRA-Digital) were measured over 2 years. The baseline characteristics of the subjects in each group were similar (P> 0.05). Decreases in femoral BMD were observed over the first year for all prosthesis designs. Bone loss was greatest (14%) in the proximal medial femur (region 7). The pattern and amount of bone loss observed was similar between all prosthesis designs (P> 0.05). Transient rises in both osteoclast (NTX) and osteoblast (OC) activity also occurred over year 1, and were similar in pattern in the 3 prosthesis groups (p> 0.05). All prostheses showed migration patterns that were true to their design type and similar improvements in clinical hip scores were observed over the 2 year study. Differences in the proposed mechanism of load transfer between prosthesis and host bone in force-closed versus shape-closed femoral prosthesis designs in THA are not major determinants of prosthesis-related remodelling.

Introduction: Polymorphisms within genes encoding bone regulatory cytokines influence individuals’ susceptibility to osteolysis after THA. We aimed to determine whether single nucleotide polymorphisms (SNPs) within these genes influence the severity of these osteolytic lesions in 272 patients with established aseptic loosening.

Methods: Assessment of osteolytic lesions was made from pre-revision radiographs in conjunction with direct visualisation in those subjects undergoing surgery. Osteolytic lesions were defined as linear (AAOS pelvic and femoral osteolysis classification grade 0) or expansile, in the presence of segmental or cavitary defects (AAOS grade 1 or greater). We analysed 11 SNPs in the pro-inflammatory cytokines IL-1A, IL-1B, IL-1RA, IL-6 and TNF; 2 SNPs within the FRZB gene, which modulates osteoblast function; and 6 SNPS in the RANK/RANKL/OPG pathway, that modulates osteoclast function.

Results: Femoral Osteolysis: Carriage of the IL-6 −174C allele was 60% in the expansile osteolysis group versus 80% in the linear osteolysis group (χ2 test p=0.007). Carriage of the OPG −163G allele was 34% in the expansile osteolysis group versus 18% in the linear group (χ2 test p=0.03). The odds ratios for expansile osteolysis associated with carriage of IL-6-174G and OPG −163G were 2.7 (1.3 to 5.7, p=0.008) and 2.3 (1.1 to 5.0, p=0.03) respectively.

Acetabular Osteolysis: No differences in SNP genotype were found between osteolysis groups.

Discussion: The IL-6-174G allele and the OPG-163G allele are over-represented in subjects with expansile femoral versus linear osteolysis, but do not relate to severity of pelvic osteolysis. These differences in association may reflect differences in the mechanism of osteolysis between the bone sites, however, replication of the results are required to confirm this differential association.

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.

Introduction: The success of cemented total hip replacements (THR) has been well documented. However, few studies have shown how patients who have had a primary THR function compare with the general population.

Materials and Methods: We prospectively collected data on 193 patients (83 males, 109 females, 1 missing) who had a primary cemented THR (Exeter stem). 25 patients had bilateral hip replacements. Patients were evaluated using the Oxford Hip Score and Short Form-36 Health Survey (SF-36) questionnaire pre operatively and at 3 months and 1, 3, 4 and 5 years follow up. SF-36 questionnaires were also completed by 8117 people from the general population, recruited from 12 General Practices in the local city. The two groups (age and sex matched) were then compared for quality of life and function.

Results: The mean age of patients in the THR group was 54 years (range 21 – 93 years). The underlying diagnosis was primary osteoarthritis in 159 patients, secondary osteoarthritis in 20 and rheumatoid arthritis in 6 patients. Post operative complications included deep vein thrombosis (2.7%), infection (1.8%) and dislocation (2.7%). There was a significant improvement in the mean Oxford Hip score post operatively in patients following THR and this trend was maintained at 5 years. Apart from physical function, for all other aspects of the SF-36 there were no significant differences between patients following THR at 5 years and that of the general population.

Conclusion: Cemented total hip arthroplasty significantly improves quality of life and can restore it to that of the general population.

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: 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: 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.