The median satisfaction score was 100 (interquartile range 75–100). However, within the individual outcome domains dissatisfaction rates were: 9% for pain; 12% for overall outcome; 14% for ADLs; and 17% for leisure activities. To explore differences in satisfaction with age, patients were divided into 3 age groups: <
60 years, 60–80 years and >
80 years. The respective rates of dissatisfaction among the age groups were 13%, 11% and 14%, which were not significantly different (p=0.33). In an analysis of gender and satisfaction, significantly more females were dissatisfied than men (14% vs 10%, p=0.01). When pain, function, quality of life, mental health and physical health were compared between patients who were satisfied (n=1834) and dissatisfied (n=251) with their overall outcome, all outcomes were significantly worse in the dis-satisfied patient group (p<
0.001 for all outcomes).
Pain: the prevalence of poor outcomes were 6% of patients with a THR, 4% with a hip resurfacing, 12% with a TKR, 9% with a UKR and 31% with a patellar resurfacing. Function: the prevalence of poor outcomes were 12% of patients with a THR, 4% with a hip resurfacing, 16% with a TKR, 9% with a UKR and 35% with a patellar resurfacing. Hip-related quality of life: the prevalence of poor outcomes were 26% of patients with a THR, 12% with a hip resurfacing, 33% with a TKR, 32% with a UKR and 67% with a patellar resurfacing. Satisfaction: the prevalence of poor outcomes were 13% of patients with a THR, 8% with a hip resurfacing, 17% with a TKR, 11% with a UKR and 45% with a patellar resurfacing.
North Bristol Trust Small Grants Scheme provided funding for the consumables for this study.
At the end of the follow up period, 11 of the 70 acetabular components (polyethylene liner or the acetabular shell) had been revised. The cumulative survival was 94.0% (95% confidence interval 88.4–99.7) with revision of the metal shell as the end point, and 84.0% (95% confidence interval 74.5–93.5) with revision surgery of the acetabular shell or liner due to any reason as an end point. Radiologically, 4 patients require acetabular revision and 22 patients had femoral osteolysis in gruen zone 7, indicative of polyethylene failure. This gave a combined revision, impending revision and zone 7 osteolysis cumulative survival of 55.3% (95% confidence interval 40.6–70.0).
This research was supported by funding from Stryker UK.
Bone stock loss is a major challenge to the revision hip surgeon. Impaction grafting is frequently the preferred option for the surgeon when faced with bone stock deficiency. This retrospective study assesses a consecutive series of patients who underwent revision hip replacement with femoral impaction grafting during the period 1994–2001. Radiographic measurement for stem subsidence was carried out by 2 independent observers on pre-operative and post-operative radiographs at 6 months, 1 year, 18 months and 2 years following surgery. Graft incorporation and trabecular remodelling were also subjectively assessed. Irradiated bone allograft was used in all cases. Sixty-nine hips were reviewed. Radiographic analysis revealed graft incorporation in 38% of cases. However, there was no evidence of trabecular remodelling. Moderate subsidence (5–10 mm) occurred in 10 cases (14.5%), and massive subsidence (>
10 mm) occurred in 5 cases (7.2%). The survivorship with re-revision or need for further surgery as the end point was 92.8% at an average of 28 months. The results obtained in this study are less favourable than other reported studies of revision of the femoral stem using impaction bone grafting. The absence of the characteristic changes of graft remodelling reported in other series raises concerns that irradiated bone graft may be a significant factor in the post-operative progress.
We compared patient-reported outcomes of the Kinemax fixed- and mobile-bearing total knee replacement in a multi-centre randomised controlled trial. Patients were randomised to the fixed- or the mobile-bearing prosthesis via a sealed envelope method after the bone cuts had been made in the operating theatre. Randomisation was stratified by centre and diagnosis. Patients were assessed pre-operatively and at eight to 12 weeks, one year and two years post-operatively. Validated questionnaires were used which included the Western Ontario MacMasters University, Short-Form 12, Mental Health Index-5, Knee Injury and Osteoarthritis Outcome Score for Knee-Related Quality of Life and Function in Sport and Recreation scales and a validated scale of satisfaction post-operatively. In total, 242 patients (250 knees) with a mean age of 68 years (40 to 80) were recruited from four NHS orthopaedic centres. Of these, 132 patients (54.5%) were women. No statistically significant differences could be identified in any of the patient-reported outcome scores between patients who received the fixed-bearing or the mobile-bearing knee up to two-years post-operatively.
Cemented, polished, tapered stems have produced excellent results, but some early failures occur in younger patients. The CPS-Plus stem (Plus Orthopedics AG, Switzerland) is a polished double taper with rectangular cross section for improved rotational stability. A unique proximal stem centraliser increases cement pressurisation, assists alignment and creates an even cement mantle. Radiostereometric analysis has demonstrated linear subsidence in a vertical plane, without any rotation or tilt. These features should improve implant durability. Midterm (5 years) results of a prospective international multicentre study are presented.
The mean Harris hip score improved from 42 preoperatively to 91. There have been no revisions for aseptic loosening and none of the stems have radiographic evidence of loosening. There has been one revision for deep sepsis. With revision for aseptic loosening as an endpoint, stem survivorship is 100%.
Our aim was to determine the pre-operative sporting profiles of patients undergoing primary joint replacement and to establish if they were able to return to sport after surgery. A postal survey was completed by 2085 patients between one and three years after operation. They had undergone one of five operations, namely total hip replacement, hip resurfacing, total knee replacement, unicompartmental knee replacement or patellar resurfacing. In the three years before operation 726 (34.8%) patients were participating in sport, the most common being swimming, walking and golf. A total of 446 (61.4%) had returned to their sporting activities by one to three years after operation and 192 (26.4%) were unable to do so because of their joint replacement, with the most common reason being pain. The largest decline was in high-impact sports including badminton, tennis and dancing. After controlling for the influence of age and gender, there was no significant difference in the rate of return to sport according to the type of operation.
The visco-elastic behaviour of acrylic bone cement is a key feature of cement-implant performance. The ability of the cement to creep in conjunction with a force-closed design of stem (collarless polished taper) affords protection of the vital bone-cement interface. Most surgeons in the UK use antibiotic-laden PMMA in primary total joint arthroplasty. In revision surgery the use of bespoke antibiotic-cement combinations is common. The aim of this study was to elicit the effect of antibiotics upon the physical properties of bone cement.
The cements used were Palacos R40 and Palacos R with gentamicin. The antibiotics added included fucidin, erythromycin, teicoplanin and vancomycin in 500mg powder aliquots up to a maximum of 1g per 40 g mix. All data were analysed using ANOVA with Bonfer-roni post-hoc test. Pearson’s correlation coefficient was used to investigate the association between physical factors (SPSS).
The visco-elastic behaviour of cement, is a key feature of cement-implant performance in total hip arthroplasty. The aim of this study was to describe the creep behaviour of the leading plain bone cements under standardised physiological in-vitro conditions.
The cements tested were Palacos R, CMW1 and Smartset GHV and Surgical Simplex P. All data were analysed using ANOVA with Bonfer-roni post-hoc test (SPSS).
Cobalt chrome-on-cobalt chrome bearing surfaces have been re-introduced despite some concerns regarding potential risks posed by soluble metallic by-products. We have investigated whether there are metal-selective differences between the levels of genetic damage caused to a human cell line when cultured with synovial fluids retrieved from various designs of orthopaedic joint replacement prostheses at the time of revision arthroplasty. Synovial fluids were retrieved from revision hip and knee arthroplasty patients with bearings made from cobalt chrome-on-cobalt chrome, cobalt chrome-on-polyethylene and stainless steel-on-polyethylene. Control synovial fluids were retrieved from primary arthroplasty cases with osteoarthritis. Synovial fluid was cultured with human primary fibroblasts for 48 hours in a cell culture system under standardised conditions. The “Comet” assay was used with an image analysis system to measure levels of DNA damage caused by the various synovial fluid samples. Synovial fluids from cobalt chrome-on-cobalt chrome and cobalt chrome-on-polyethylene joint replacements both caused substantial levels of genetic damage as detected by the Comet assay. Synovial fluids retrieved from stainless steel-on-polyethylene joints caused low levels of damage. The difference between these groups was highly statistically significant (p<
0.001). Control synovial fluids from osteoarthritic joints caused minimal changes. Atomic absorption spectroscopy demonstrated that the metal-on-metal synovial fluids contained the highest levels of cobalt and chromium. Different alloys used in orthopaedic implants are associated with different levels of DNA damage to cultured human cells in vitro. We are able to demonstrate that this damage is attributable at least in part to the metal content of the synovial fluid samples. We have no evidence for any long-term health risk to patients with such implants.
Restoration of bone stock is the single greatest challenge facing the revision hip surgeon today. This has been dealt with by means of impaction grafting with morsellised allograft from donor femoral heads. Alternatives to allograft have been sought. This study investigates the use of a porous biphasic ceramic in impaction grafting of the femur. Impaction grafting of the femur was performed in four groups of sheep. Group one received pure allograft, group two 50% allograft and 50% BoneSave, group three 50% allograft and 50% BoneSave 2 and group four 10% allograft and 90% BoneSave as the graft material. Function was assessed by measuring peak vertical reaction forces. Changes in bone mineral density were measured by DEXA scanning. Loosening and subsidence were assessed radiographically and by examination of explanted specimens. All outcome measures showed no statistically significant difference between the four groups after eighteen months of full function.
The National Institute for Clinical Excellence (NICE) was set up to provide patients, health professionals and the public with authoritative, robust and reliable guidance on current “best practice”. To determine how useful for NICE guidelines for Selection of Prostheses for Primary Total Hip Replacement were to patients who were undergoing total hip replacement (THR) and the health professionals who were looking after them. We surveyed 100 patients, 50 Orthopaedic Surgeons, 40 Orthopaedic nurses and posted a questionnaire to GPs, to which 79 replied (56% response rate). 19% of patients had heard of NICE but only 2% were aware of the existence of NICE guidelines on THR and 1% found them useful. Almost all orthopaedic surgeons had heard of NICE and their guidelines for THR, with 74% knowing what the guidelines actually stated but only 14% finding them useful. 78% of surgeons believed that their preferred hip replacement conformed to NICE guidelines, 2% knew that they did not conform and 20% did not know. 27% of general practitioners knew of the guidelines, but only 5% knew what they actually stated and 1% found them useful in their practice. Most nursing staff working in orthopaedic areas had heard of NICE (83%). 43% knew of the NICE guidelines but only 13% knew the actual guidelines and % found them useful. NICE has failed to communicate its guidelines to both patients and the public. None of the groups found the guidelines useful. NICE has failed to fulfil its mission statement and may instead have other motives, such as empowering centralised regulation of healthcare in the NHS.
Metal-on-metal bearing surfaces have been reintroduced for use in total hip replacement, despite concerns regarding the potential risks posed by metallic by-products. We have compared periprosthetic tissues from metal-on-metal and metal-on-polyethylene hip replacements at revision surgery with control tissues at primary arthroplasty. Tissues were obtained from 9 control, 25 contemporary metal-on-metal, 9 CoCr-on-polyethylene and 10 titanium-on-polyethylene hip replacement arthroplasties. Each was processed for routine histology with Haematoxylin and Eosin. Quantitative stereological analysis was performed at the light microscopic level. Metal-on-metal sections showed more surface ulceration and this was correlated with the density of inflammation in the deeper tissues layers. Metal-on-metal tissues displayed a pattern of well-demarcated tissue layers, which were rarely seen in metal-on-polyethylene cases. In metal-on-polyethylene cases, the inflammation was predominantly histiocytic. Metal-on-metal cases by contrast showed a lymphocytic infiltrate with abundant plasma cells. Metal-on-metal tissues showed a striking pattern of peri-vascular inflammation with prominent lymphocytic cuffs especially deep to areas of surface ulceration. Levels of inflammation were higher in cases revised for failure than in those retrieved at autopsy or exploratory surgery. Total replacement and surface replacement designs of metal-on-metal arthroplasty showed similar histological changes. Plasma cells were not seen in any of the metal-on-polyethylene cases. The differences between the patterns of inflammation and cellular infiltration seen in metal-on-metal and metal-on-polyethylene tissues were highly statistically significant. The pattern and type of inflammation in periprosthetic tissues from metal-on-metal and metal-on-poly-ethylene arthroplasties is very different. Our findings support the conclusion that metal-on-metal articulations are capable of generating a form of immunological response to metallic wear debris that has not been described previously. The incidence and clinical implications of these immunological responses in failed metal-on-metal joints are unknown.
In contrast, the release of the inflammatory cytokine TNF-α and the multifunctional growth factor TGF-β-2 occurred at lower doses (0.0005 to 5 μm3/cell for TNF-α and 0.5 to 50 μm3/cell for TGF-β-2). No release of IL-6 was detected at any dose. Only growth factor FGF-23 was increased in similar pattern to the DNA damage.
Wear debris from worn cobalt chrome joint replacements causes an increase in chromosomal translocations and aneuploidy. In this study the relationship between the amount of DNA damage and the changes in gene expression was investigated in human fibroblasts after exposure to artificial cobalt chrome particles. The comparison was made with different doses of particles, at different time intervals and in fibroblasts of different ages, those that had completed 10 population doublings (10 PD fibroblasts) and those that had completed 35 population doublings (35 PD fibroblasts). The genes (TGF-©¬2, p38 MAPK, Integrin ¥â1, SOD1, Caspase 10, PURA, FRA-1 and VNR) were chosen after a previous screen with cDNA microarrays. The percentage of senescent cells was evaluated using an immunohistochemical assay for ¥â-galactosidase activity. The 35 PD fibroblasts showed significantly more ¥â-galactosidase activity than the 10 PD fibroblasts. The level of DNA damage, as detected with the alkaline comet assay, was greater at higher doses, at longer exposures (up to 24 hours) and in 10 PD fibroblasts. The expression of all the genes listed above was generally lower after exposure to cobalt chrome particles using semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The reduction in gene expression, like the increase in DNA damage was greater at higher doses and at longer exposure times. After 24hr exposure the reduction in gene expression was greater in 10 PD fibroblasts compared to 35 PD fibroblasts. After 6hr exposure this was only true at higher doses of particles and the opposite was seen after a lower dose of particles. These results show that levels of gene expression of TGF-©¬2, p38 MAPK, Integrin ¥â1, SOD1, Caspase10, PURA, FRA-1 and VNR may be correlated with the level of DNA damage and that this depends on the dose and length of exposure and the age of the cells. This highlights the potential importance of these genes in the mutagenicity of cobalt chrome particles in human fibroblasts.
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.
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.
Polyethylene liners of modular acetabular components wear and sometimes need to be replaced, despite the metal shell being well fixed. Replacing the liner is a relatively simple procedure, but very little is known of the outcome of liner revision. We prospectively followed up 1126 Harris-Gallante 1 metal backed, uncemented cups for between 9 and 19 years. 38 (3.4%) liners out of 1126 acetabular components wore and required revision. These revisions were then followed up for a mean of 4.8 years. The rate of dislocation was 28.9%. Nine of the dislocations were single dislocations and 2 were recurrent. The overall re-revision rate was 3 out of 38 total hip replacements (7.9%) at a mean follow up of 4.8 years. This gives a 92.1% survivorship at just under 5 years. In isolated liner revision we had a complication rate of 23%. In liner revision combined with stem revision we had a complication rate of 48%. Possible reasons for high dislocation rates are discussed. Leaving the well fixed acetabular shell in-situ leads to an increased risk of instability. However, this needs to be balanced against the otherwise low complication rate for liner revision. Patients should be consented accordingly
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.
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.
There were 27 male and 46 female patients (8 bilateral). The mean age was 42 (range 18 to 57). Secondary osteoarthritis was the most common presenting pathology. There were no exclusion criteria beyond those applicable to any replacement arthroplasty.
There was no evidence of stem subsidence. A sclerotic line was frequently observed around the non-coated distal stem. Buttressing of the coated area was almost universally seen in the metaphyseal region. There were no radiolucent lines in any of the zones around the textured area in the metaphyseal region.
The static properties of bone cements have been widely reported in the literature (Lewis, 1997, Khun, 2000, Armstrong 2002). Commercial bone cements are expected to perform above the minimum values in static tests specified by ISO 5833: 2002. It has been suggested that the viscoelastic properties of bone cement, such as creep and stress relaxation, might bear more relevance to the in-vivo behaviour of the cement-implant construct (Lee 2002). This study aimed to compare numerous properties of Simplex P, Simplex Antibiotic and Simplex Tobramycin and identify those properties most sensitive to subtle changes in cement composition. The three cements were chosen on the basis that they are characterised by the same liquid and powder compositions, the only difference being represented by the type and amount of added antibiotics. In Simplex Antibiotic the additives are 0.5g Erythromycin and 3 million I.U. Colistin, while in Antibiotic Simplex with Tobramycin the only additive is 0.5g of Tobramycin. The static properties of the cements were assessed following protocols described in ISO 5833: 2002, while the viscoelastic properties of the cement were measured with in-house developed apparatus in quasi-static conditions. Creep and stress relaxation tests were performed in four point bending configuration. Porosity was measured on the mid cross section of the creep samples using a digital image technique. All cements exhibited properties compatible with the ISO standard, but in plain Simplex the ISO minimum for bending and compressive strength was within the variation of the batches tested. Bending strength measurements were the least sensitive to differences in the cements. Plain Simplex displayed lower bending and compressive strength but higher bending modulus than the antibiotic laden options. The bending modulus could only discriminate between Simplex P and Simplex Antibiotic (p=0.02). Differences in the compressive strength of the three cements were significant, with the plain option being the weakest. Stress relaxation only discriminated between plain and Tobramycin loaded cement (p=0.028), while creep was more sensitive to differences and allowed distinction between plain and antibiotic loaded bone cements. The creep behaviour correlated with the cross sectional porosity measurements. This study demonstrated that the static tests specified by the current international standard are not as sensitive to subtle changes in the composition of the material as the time temperature dependent parameters characteristic of creep and stress relaxation. The authors advocate the evaluation of time and temperature dependent characteristics as a complement to the current standard.
A cohort group of 53 CR Kinemax plus TKR from the Bristol Knee group was matched for age and sex. They had the same parameters measured.
Joint line: elevation K+ LCS 0–2 mm (16/48) = 33% (26/53) = 49% 2–5 mm (14/48) = 29% (14/53) = 26%>
5 mm (18/48) = 38% (12/53) = 25% There was no significant difference in the ROM or Oxford Knee Score when the joint line was not elevated versus elevated for each prosthesis. However, there was suggestion that the ROM in LCS might be more sensitive to joint line changes, although this was not significant. ROM K+ LCS Normal joint line 116° 105° Elevated joint line 108° 101°
The radiological picture was evaluated for signs of incorporation, remodelling, loosening and migration of the cemented acetabular component. Clinical evaluation was from the last clinic visit and included the presence of pain, mobility status, range of movement and patient satisfaction. Revision was the end point of the study
The National Institute for Clinical Excellence (NICE) was set up in the UK ‘to provide patients, health professionals and the public with authoritative, robust and reliable guidance on current best practice. In March 2000, NICE provided national guidelines for the selection of prostheses for total hip replacement.
Aseptic loosening remains a long-term problem in total hip replacement. This phenomenon is prevalent even if modern cementing techniques seem to have reduced its incidence. Osteolysis has been deemed as a disease of access to fixation interfaces ( Femoral component heating was first proposed as a method to reduce the curing time of bone cement ( The model femora used for this study were maintained at a constant temperature of 37C while the stem temperature varied between 21, 37 and 44C. The femoral moulds were formed from dental plaster with a similar thermal conductivity to bone. Mould sizes were created to generate cement mantles of 2, 5 and 7.5mm thickness. In the 2mm Simplex P cement mantles there was very little porosity evident. It was concentrated in the proximity of the stem when the component was kept at 21C and disappeared as the stem was heated to higher temperatures. Minimal porosity could be identified in the thicker mantles with no apparent differences between temperatures. There were no temperature trends evident from within this cement group. Palacos R cement has been reported to have a higher porosity than Simplex in a number of studies ( This study analyses the changes in porosity across the mantle of the cement as the temperature of the stem component is increased. The initial results confirm that the porosity at the stem cement mantle is decreased but indicate that the porosity within the body of the cement is increased as the temperature of the stem is increased.
Metal-on-metal joint replacements have been reintroduced despite some concerns regarding the potential risks posed by soluble metallic by-products. We have investigated whether there are metal selective differences between the levels of genetic damage caused to a human cell line when cultured with synovial fluids retrieved from orthopaedic joint replacement prostheses at the time of revision arthroplasty.
Kaplan-Meier survivorship analysis was performed.
Irradiated allograft bone may help to reduce the risk of transmission of infectious agents from donor to recipient. The purpose of this study was to establish the results of impaction bone grafting of acetabular defects using irradiated allograft bone. Patients treated with impaction bone grafting of ace-tabular defects between 1994 and 2000 were reviewed retrospectively. The mean follow-up was 50months (range 30–96months). Case notes and Xrays were reviewed and analysed. The Paprosky grade of acetabular defects was determined. Functional outcomes were determined by way of self-administered questionnaires. Complete records and Xrays were obtained for 33 patients who underwent impaction bone grafting of the acetabulum using freeze-dried, irradiated bone. The Paprosky classifications of the defects were as follows: 3 type 1, 10 type 2A, 4 type 2B, 4 type 2C, 10 type 3A and 2 type 3B. There were no complications associated with the bone grafts and no patient required reoperation. Review of serial Xrays confirmed ingrowth of host bone. The functional results obtained were as follows: 17 patients (52%) could walk an unlimited distance. 11 patients (33%) required no walking aids whilst a further 17 (52%) required a single cane to mobilise. 21 patients (64%) were able to use public transport after the operation. 20 patients (61%) reported little or no pain. 9 patients (28%) had no limp and 14 patients (42%) had a slight limp. Overall 29 patients (88%) declared themselves to be satisfied with the outcome of their surgery. 32 patients (97%) improved functionally after their operation. These results indicate that satisfactory results can be achieved with impaction bone grafting using irradiated, frozen allograft bone. The use of irradiated bone graft can potentially reduce the risks of disease transmission from donor to recipient without compromising the surgical results.
We report the results of seventy-six Harris Galante Porous Cups (HGP 1) in sixty-three patients treated by Total Hip Arthroplasty (THA) with a diagnosis of avascular necrosis (AVN) of the femur (grade III and IV). The cups were inserted between 1986 and 1994 and followed prospectively. Seventy hips with a follow up of more than five years (mean 7.6 years) were reviewed. At last review the mean Harris Hip Score was 94 (standard deviation (&
dcl001;) .8), preoperatively the mean had been 29 (&
dcl001;14.7). Radiographically there was no evidence of acetabular migration. The revision rate of the femoral prosthesis was 8.6%, however only three stems (4.3%) were revised for loosening the rest being revised to allow down sizing of the femoral head. The revision rate for the acetabular prosthesis was 7.1%, (five cups). At the time of revision none of the cups were clinically loose and only required the liner to be changed. The complication rate was low with no deep infections or dislocations and only nine hips, (11.8%) with grade III heterotopic ossification. Survival analysis for both stem and cup at 8 years is 96.3% (confidence interval 91 – 100%), with a worst-case survival of 93.6%, (C.I 87.4 – 99.9%) Previous studies of patients undergoing cemented THA for the treatment of advanced AVN have reported a high incidence of component loosening. This study shows good medium term results using the Harris Galante Porous cup for acetabular reconstruction with cemented femoral components for the treatment of this difficult problem.
Presently, many instruments exist for assessing both patient - and surgeon-based satisfaction after joint replacement, including both generic (measures of general health status) and disease specific measures. As such, the US PORT study (1995) recommends use of both the WOMAC and SF-36. However, this means that studies need to incorporate at least these two lengthy questionnaires into protocols, which increases the pressure on patients for both time and difficulty, but also introduces some duplication of data. The SF-36 has been successfully reduced and validated to a 12 item questionnaire (SF-12) which can be used as a summarised generic health score. It would be of great benefit if a reduced version of the WOMAC could be derived to give a similar summarised disease-specific measurement tool. To derive and assess the validity of a reduced function scale of the WOMAC for patients with osteoarthritis of the hip and knee. All unilateral data from 12 centres world-wide (UK US Canada and Australia) involved in an international, multi-centre outcome study for patients undergoing TKR were included for analysis. The reduced scale was derived from pre-op and 3 month post op data using a combination of data-driven analysis and purely clinical methods. The reduced WOMAC was then extensively validated in three key areas; validity, reliability and responsiveness using 12 month post-op data from the study and data from the Medicare Hip Replacement Study. Data from 898 patients pre-operatively and 806 patients at 3-months were used for the data driven section of analysis. For the clinical section, 30 members of the orthopaedic community were surveyed as to their opinions of which items should be retained in the reduced version of the scale. These results were then combined to produce a reduced function scale of 7 items to be used in conjunction with the 5-item pain scale. The questions remaining in the scale (and their original number in the scale) were: 2) ascending stairs, 3) rising from sitting, 6) walking on flat, 7) getting in/out of car, 9) putting on socks/stockings, 10) rising from bed and 14) sitting. This reduced scale was then scrutinised to ensure it’s validity (both construct and content), reliability (both internal consistency and reproducibility) and responsiveness (using Standardised Response Means). When examining 12 month data the reduced scale compared favourably with the full scale both overall, and when sub-divided by age, sex and country. It’s construct validity was confirmed by significant positive correlation with the SF-36 physical component score, the knee society function score, the Oxford knee score, and for the hip data, the Harris hip score and SF-12 physical component score. Cronbach’s alpha was consistently high (α>
0.85) with the reduced scale, showing it to be reliable, and the SRM’s indicated that the reduced scale may even be better at detecting change than the full scale. This reduced WOMAC has been successfully derived and validated for use as a summarised and more practical version of the full WOMAC scale.
Periprosthetic fractures may occur intraoperatively or postoperatively. The incidence of is approximately 0.6% in primary and 2.4% in revision total hip arthroplasty. Predisposing factors include stress risers, osteolysis, osteopoenia, singly or in combination. Focusing on postoperative fractures, this paper provides a management algorithm. If the fracture is stable, conservative treatment is appropriate. If the fracture is not stable, one needs to determine whether the prosthesis is loose or not. If the prosthesis is loose, further management will depend on the quality of the bone stock. Good bone stock will allow revision with a long stem or impaction grafting, while poor bone stock will require extensive allografting. Similarly, the adequacy of the bone stock determines the management regime if the pros-thesis is not loose. In the presence of good bone stock, it is usually possible to carry out open reduction and internal fixation. Poor bone stock requires bicortical onlay allografting. From 1994 to 1998 36 periprosthetic fractures, 14 with stable implants and 22 with unstable, were treated. The stable implants were treated with Dall Miles plates, fixed with cables and crimp-sleeves, bicortical screws distal to the fracture and unicortical screws proximally. The fracture united in 11 hips, two of which subsequently required prosthetic revision for femoral loosening. In one hip the fixation failed with fracture of the cables. Despite other adverse reports, this type of system is recommended for fixation of periprosthetic fractures where the prosthesis is stable. The 22 periprosthetic fractures with unstable implants were treated using the Bicontact long stem revision implant. Two distal interlocking screws provided early rotational and axial stability, and 14 patients had additional allografting. Radiological evidence of fracture healing was apparent in all cases. One prosthesis subsided by more than 5 mm with fracture of the interlocking screws. Cementless long stem revision is the treatment of choice for periprosthetic fractures associated with a loose implant. To ensure successful outcome it is necessary to determine the extent of the fracture, to assess fracture stability and to appreciate the available and appropriate treatment options. It is necessary to ‘be prepared’: these are challenging problems and the final decision often hinges on intraoperative findings.
Because there are a number of complicating factors, total hip arthroplasty (THA) performed following acetabular fractures has a less favourable prognosis than when done for primary degenerative arthritis. Patients who have had ace-tabular fracture and present for consideration of THA need careful clinical and radiological assessment. Investigation should include AP and lateral radiographs, 45° inlet/outlet views, obturator and iliac obliques, Judet views and CT scan, with or without 3D reconstruction. There are various classifications defining whether the bone deficiency is contained or uncontained and the extent of the structural defect. Treatment options include autograft, allograft together with mesh, screws, plates, rings, cages, etc. It is probably preferable to undertake THA sooner (as soon as there is radiological evidence of incongruent articular surfaces) rather than later, as this reduces the delay between fracture and recovery from THA, and any inadequate reduction can be minimised or corrected. The surgical approach must allow adequate access for the intended reconstruction. Small contained or uncontained defects can be treated with cemented or cementless implants and limited grafting. Large defects require structural reinforcement, bone grafting, a retaining cage and, unless a custom-made implant is used, cemented fixation. Potential problems at the time of surgery include sciatic nerve injury (beware the ‘double crush syndrome’) obstructive hardware, heterotopic ossification, avascular necrosis of the acetabulum and occult infection. Patients who are elderly or who present with markedly impacted fracture, extensive abrasion or fracture of the femoral head, displaced femoral neck fracture, and extensive acetabular comminution in the presence of osteopoenic bone, may warrant acute management with THA. Early experience of THA in the treatment of selected acute fractures is encouraging. However, the clinical results of THA after fractures of the acetabulum are often disappointing, and there is no current evidence that open reduction and internal fixation improves the success of the subsequent THA. THA following acetabular fractures is a challenging procedure with a high complication rate. Appropriate investigation and preoperative planning reduces the risk of complications.
We reviewed the outcome of prosthesis-to-bone fixation of the rough titanium femoral stem of an Ultraloc prosthesis (Zimmer, USA). Between 1989 and 1991, 41 of 55 patients were traced for long-term review at a mean of 107 months (55 to 139). The primary pathology was avascular necrosis in 18 patients, osteoarthritis in 16, ankylosing spondylitis in two and Perthes’ disease in one, and there were two cases each of trauma and dysplasia. There was an equal number of men and women, whose mean age at operation was 47 years (24 to 66). Radiological assessment of the stems revealed well-fixed stems in 40 patients (97.6%). In 20 stems small granulomata due to polyethylene wear were found in Gruen zones 1 and 7, and in one stem in zones 1, 6 and 7. Only one stem required revision for loosening (done at 59 months), but cups (48.8%) were loose. Three patients required revision owing to polyethylene wear and one for sepsis. In all four cases, removal of the stem was extremely difficult. The remaining 16 hips await revision. Although the results obtained using an Ultraloc prosthesis are poor, from the point of view of fixation the stem has functioned successfully. However, the formation of granulomata causes cup loosening.
We evaluate the results of total hip arthroplasty using either a porous-coated or a hydroxyapatite (HA) coated femoral component. For a prospective trial we selected a cohort of young patients with a mean age of 39 (19 to 56). They were randomly selected to have either a one-third porous-coated or one-third HA-coated uncemented femoral component. One of two experienced hip surgeons performed the operations. Within the constraints of pathology, the approach and surgical technique was the same in all the cases. Patients were followed-up clinically and radiologically for a mean period of 102 months (87 to 113). To date there have been no revisions. All components have remained well fixed and there is no evidence of progressive subsidence. We found no significant difference between porous-coated or HA-coated stems.
Reports in the literature of the incidence of dislocation following primary total hip arthroplasty (THA) vary from 0.5% to 5%. Contributing factors include surgical approach, loss of the abductor mechanism, a decreased offset of the hip joint, malorientation of the components, specific design features of the components, soft tissue laxity and lack of patient compliance. The increased rate of dislocation with a posterior approach has been dramatically reduced with an enhanced posterior soft tissue repair. Component features associated with an increased risk of dislocation include reduced head/neck offset, an asymmetrical cup and possibly the head size. Component malorientation is probably the most important factor leading to recurrent dislocation. With the patient in a lateral position, there can be unpredictable variation in the position of the pelvis, and intraoperative movements aggravated this. Uncertainty about the position of the pelvis at the time of insertion of the acetabular component may lead to malpositioning. The surgeon should attempt to ensure adequate repair of the posterior capsule and external rotators. It is important to reproduce the offset, insert the components with the correct orientation, avoid impingement, and ensure patient compliance in the early postoperative period. Dislocations are considered early if they occur within three months of THA and late after three months, and management varies accordingly. While every effort should be made to avoid dislocation following THA, there is no learning curve: reviewing a series of 10 400 THA procedures performed at the Mayo Clinic, Woo and Morrey (1982) reported that the dislocation rate remained between 2% and 3%.
We report the results of a 4- to 17-year clinical and radiological follow-up of 264 Charnley first-generation stems in comparison with those of 402 second- and subsequent-generation stems. The incidence of fracture was 4.1% in first-generation stems and 0.5% in second- and subsequent-generation stems. The incidence of stem loosening requiring or likely to require revision was 3.1% in first-generation and 11.4% in second-generation stems. We believe that the increased loosening rate in second- and subsequent-generation stems is due to their larger cross-sectional area, which produces an increase in flexural stiffness.