Trabecular metal (TM) augments are designed to support an uncemented socket in revision surgery when adequate rim fit is not possible. We have used TM augments in an alternative arrangement, to contain segmental defects to facilitate impaction bone grafting (IBG) and cementation of a cemented socket. However, there is a paucity of literature supporting the use of this technique. We present one of the largest studies to date, reporting early outcomes of patients from a tertiary centre.

A single-centre retrospective analytical study of prospectively collected data was performed on patients who had undergone complex acetabular reconstruction using TM augments, IBG and a cemented cup. All patients operated between 2015 and 2019 were included. We identified 105 patients with a mean age of 74yrs. The mean follow-up was 2.3 years(1–5.5yrs). Our primary outcome measure was all-cause revision of the construct. The secondary outcome measures were, Oxford hip score (OHS), radiographic evidence of cup migration/loosening and post-op complications.

Eighty-four out of 105 patients belonged to Paprosky grade IIb, IIc or IIIa. Kaplan-Meier survivorship for all-cause revision was 96.36% (CI, 90.58–100.00) at 2 years with 3 failures. Two were due to early infection which required two-stage re-revision. The third was due to post-operative acetabular fracture which was then re-revised with TM augment, bone graft and large uncemented cup. Pre-op and post-op matched OHS scores were available for 60 hips(57%) with a mean improvement of 13 points. Radiographic analysis showed graft incorporation in all cases with no evidence of cup loosening. The mean vertical cup migration was 0.5mm (Range −5 to 7mm). No other complications were recorded.

This study shows that reconstruction of large acetabular defects during revision THA using a combination of TM augments to contain the acetabulum along with IBG to preserve the bone stock and a cemented socket is a reliable and safe technique with low revision rates and satisfactory clinical and radiographic results. Long term studies are needed to assess the possibility of preservation and regeneration of bone stock.

The aims of this study were to examine the repeatability of measurements of bone mineral density (BMD) around a cemented polyethylene Charnley acetabular component using dual-energy x-ray absorptiometry and to determine the longitudinal pattern of change in BMD during the first 24 months after surgery.

The precision of measurements of BMD in 19 subjects ranged from 7.7% to 10.8% between regions, using a four-region-of-interest model. A longitudinal study of 27 patients demonstrated a transient decrease in net pelvic BMD during the first 12 months, which recovered to baseline at 24 months. The BMD in the region medial to the dome of the component reduced by between 7% and 10% during the first three months, but recovered to approximately baseline values by two years.

Changes in BMD in the pelvis around cemented acetabular components may be measured using dual-energy x-ray absorptiometry. Bone loss after insertion of a cemented Charnley acetabular component is small, transient and occurs mainly at the medial wall of the acetabulum. After two years, bone mass returns to baseline values, with a pattern suggesting a uniform transmission of load to the acetabulum.

Aims

Limited implant survival due to aseptic cup loosening is most commonly responsible for revision total hip arthroplasty (THA). Advances in implant designs and materials have been crucial in addressing those challenges. Vitamin E-infused highly cross-linked polyethylene (VEPE) promises strong wear resistance, high oxidative stability, and superior mechanical strength. Although VEPE monoblock cups have shown good mid-term performance and excellent wear patterns, long-term results remain unclear. This study evaluated migration and wear patterns and clinical and radiological outcomes at a minimum of ten years’ follow-up.

We investigated the revision rates of primary total hip replacement (THR) reported in the National Joint Registry (NJR) by types of bearing surfaces used. We analysed THR procedures across all orthopaedic units in England and Wales. Our analyses estimated all-cause and cause-specific revision rates. We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with head and shell/liner combinations. We used flexible parametric survival models to estimate adjusted hazard ratios (HR). A total of 1,026,481 primary THRs performed between 2003–2019 are included in the primary analysis (Monobloc: n=378,979 and Modular: n=647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n=7,381 and Modular: n=13,488). Compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the all-cause risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome or stainless steel head and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any post-operative period. Compared to patients with a cobalt chrome head and HCLPE liner primary THR, the all-cause risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic or oxidised zirconium head and HCLPE liner had a lower risk of revision throughout the entire post-operative period. The all-cause and indication-specific risk of prosthesis revision, at different time points following the initial implantation, is lower for implants with a delta ceramic or oxidised zirconium head and a HCLPE liner/cup than commonly used alternatives such as cobalt chrome heads and HCLPE liner/cup

Hip bearing surfaces materials are typically broadly reported in national registry (metal-on-polyethylene, ceramic-on-ceramic etc). We investigated the revision rates of primary total hip replacement (THR) reported in the National Joint Registry (NJR) by detailed types of bearing surfaces used. We analysed THR procedures across all orthopaedic units in England and Wales. Our analyses estimated all-cause and cause-specific revision rates. We identified primary THRs with heads and monobloc cups or modular acetabular component THRs with detailed head and shell/liner bearing material combinations. We used flexible parametric survival models to estimate adjusted hazard ratios (HR). A total of 1,026,481 primary THRs performed between 2003–2019 were included in the primary analysis (Monobloc cups: n=378,979 and Modular cups: n=647,502) with 20,869 (2%) of these primary THRs subsequently undergoing a revision episode (Monobloc: n=7,381 and Modular: n=13,488). Compared to implants with a cobalt chrome head and highly crosslinked polyethylene (HCLPE) cup, the overall risk of revision for monobloc acetabular implant was higher for patients with cobalt chrome or stainless steel head and non-HCLPE cup. The risk of revision was lower for patients with a delta ceramic head and HCLPE cup implant, at any post-operative period. Compared to patients with a cobalt chrome head and HCLPE liner primary THR, the overall risk of revision for modular acetabular implant varied non-constantly. THRs with a delta ceramic or oxidised zirconium head and HCLPE liner had a lower risk of revision throughout the entire post-operative period. The overall and indication-specific risk of prosthesis revision, at different time points following the initial implantation, is reduced for implants with a delta ceramic or oxidised zirconium head and a HCLPE liner/cup in reference to THRs with a cobalt chrome head and HCLPE liner/cup

Between January 1988 and January 1991 we performed 100 consecutive cemented total hip replacements using a zirconia head, a titanium alloy stem and a polyethylene cup. We reviewed 78 of these hips in 61 patients in detail at a mean of 5.8 years (1 to 9). Aseptic loosening was seen in 11 hips (14%). Eight needed revision. In total, 37 cups (47.5%) showed radiolucent lines, all at the cement-bone interface, with 18 (23%) involving all the interface. Of the 78 femoral implants, 17 (21.7%) showed radiolucent lines, and two, which had a complete line of more than 1 mm thick, definite endocortical osteolyses. There was also an abnormally high incidence of osteolysis of more than 2 mm at the calcar. Survivorship analysis showed that only 63% were in situ at eight years. These worrying results led us to abandon the use of zirconia heads, since at the same hospital, using the same femoral stem, cement and polyethylene cup, but with alumina femoral heads, the survival rate was 93% at nine years. We discuss the possible reasons for the poor performance of zirconia ceramic

It is unknown whether the risk of periprosthetic femoral fracture is the same in patients with two different bearing surfaces, ceramic on ceramic (CoC) and ceramic on polyethylene (CoP). We retrospectively reviewed selected 126 patients (252 hips) with bilateral THA (one ceramic-ceramic, AL/AL and the contralateral ceramic-polyethylene, AL/PE) who had THA performed between from 1981 to 1985 for osteonecrosis. Surgery was performed in patients who were average 50 years (range 30–60) old. The stem was always cemented and the same for both sides. The alumina head was 32 mm in diameter. The acetabular component was a polyethylene cup or an alumina cup and was always cemented. The mean follow-up for living patients was 35 years (range 32 to 36), and the mean follow-up for patients who had died was 23 years range 15 to 30). 14 periprosthetic fractures occurred in 252 hips after THA, representing an overall prevalence of 5.5% for hips and 11% for patients. Periprosthetic fractures increased in number with followup: 3 patients (3%) sustained fractures within 10 years of their primary implantation, 7 within 20 years, 10 within 30 years, 14 (11%) within 35 years. The risk of fracture was influenced (p=0.01) by the bearing surfaces at the time of prosthetic implantation, low (1%) for ceramic on ceramic (1/14 fractures; 1/126 hips), higher (10%) for ceramic on PE (13/14; 13/126). When the contralateral hip of the same patient is the control, the long-term risk of periprosthetic fracture on the side with PE cup is greater (10%) than on the side with ceramic/ceramic bearing

A reduced femoral offset in total hip replacement has been thought to be disadvantageous. We reviewed the results of 54 consecutive primary total hip replacements in 49 patients (mean age of 68 years) performed between August 1990 and December 1994, with a mean follow-up of 8.8 years (. sd. 2.1). The mean pre-operative femoral offset for these hips was 41 mm (. sd. 7.4). All patients received a low-offset Charnley stem and a polyethylene cup inserted by a single surgeon. At their latest follow-up, surviving patients had a significant improvement in the performance of their hip. Three had undergone revision, one each for deep infection, recurrent dislocation and late pain with subluxation. No hips had been revised, or were at risk of revision, for aseptic loosening. The mean annual linear rate of wear was 0.2 mm (. sd. 0.08) for the whole group. There was no correlation between the pre-operative femoral offset and the post-operative rate of wear. Our survivorship estimate was 91% when revision for any reason was taken as an end-point, but 100% if aseptic loosening was considered as the end-point. Our study demonstrates that a low-offset femoral stem can produce good, medium-term results

Introduction. Cross linked polyethylene (XLPE) has gained popularity as a bearing surface of choice for younger patients despite only medium term results being available for wear rates. Concern remains regarding the long-term stability and durability of these materials. In order to address these issues we present the longest radiological and clinical follow-up of XLPE. Patients/Materials & Methods. Since 1986, we have prospectively studied a group of 17 patients (19 hips) that underwent a cemented Charnley low friction arthroplasty using a combination of 22.225mm alumina ceramic femoral head, a modified Charnley flanged stem and a chemically cross-linked polyethylene cup. We now report the 28 year clinical and radiological results. Results. At the latest review nine patients (11 hips) were still attending for clinical and radiographic follow-up at a mean of 27.5 years (26 – 28). The mean age at surgery in this group was 47 years (26 – 58). Seven patients died whilst still under follow-up, and one was revised at 17 years for late deep infection following urological surgery. There have been no mechanical failures of the components and no aseptic loosening. The mean initial penetration rate at 1 year was 0.13mm/year; between one and four years was 0.034mm/year; and between 4 years and latest follow-up (mean 27.5 years) was 0.007mm/year. One patient in this group subsequently had a contralateral Charnley metal on UHMWPE hip replacement and had a total cup penetration of 6.1mm at 27 years, compared to 0.41mm at 28 years in the XLPE and alumina ceramic combination. Conclusion. The clinical and radiological results in this group of patients remain excellent with no aseptic loosening. There was an initial bedding in period, after which there was an extremely low wear rate. The results highlight the long term stability and durability of cross-linked polyethylene when used in combination with a small diameter alumina ceramic head

We report a long-term review of 60 acetabular components revised using impacted, morsellised bone allografts and a cemented polyethylene cup. The acetabular defects were cavitary (37) or combined (23). Follow-up was for a mean 11.8 years (10 to 15). Further revision was needed in five hips, two for septic and three for aseptic loosening. The overall survival rate at 11.8 years was 90%; excluding the septic cases it was 94%. Acetabular reconstruction with impacted morsellised cancellous grafts and cement gives satisfactory long-term results

We report the results of our continued review of 14 hip arthroplasties using alumina ceramic femoral heads with cross-linked polyethylene cups. There have been no complications and a very low rate of penetration. This was 0.02 mm per year after an initial ‘bedding-in’ period of two years. There has been no change in the mean rate between our earlier study at six years and the current results at 10 to 11 years. The use of these bearing surfaces appears to reduce the potential amount of polyethylene debris and may provide the next logical stage in the development of the Charnley low-friction arthroplasty

Aims

To investigate the effect of polyethylene manufacturing characteristics and irradiation dose on the survival of cemented and reverse hybrid total hip arthroplasties (THAs).

Since wear and loosening of the ultra-high-molecular-weight polyethylene cup are factors which limit the life of an arthroplasty we have attempted to identify factors associated with either low wear (0.02 mm/year or less) or high wear (0.2 mm/year or more). In a series of 1434 Charnley low-friction arthroplasties (1092 patients) 190 (13.2%) showed low wear while 149 (10.4%) showed high wear. We used chi-squared test to assess the significance of various factors. The significant factors of the low-wear group were female gender (p = 0.042), rheumatoid arthritis (p = 0.014), Charnley grade C (p = 0.03) and varus position of the stem (p = 0.003). The use of acetabular cement pressurisation (p = 0.07) and medialisation of the cup (p = 0.07) approached significance. In the high-wear group there was a predominance of men (p = 0.042) with osteoarthritis (p = 0.006) as the underlying hip pathology, and the stem in a valgus position (p = 0.023). Support of the cup by the rim of the acetabulum approached significance (p = 0.07). There was no statistical significance between the two groups for revision for aseptic loosening of the stem or fracture of the stem (p = 0.49). There was a highly significant difference (p < 0.0001) between the two groups for revision for wear and aseptic loosening of the cup, 5.3% compared with 39%. Changes in the cup geometry are probably sufficient to explain the increasing incidence of loosening and revisions with the increasing depth of penetration of the cup. There is much to be gained from the use of a low-wearing ceramic-ultra-high-molecular-weight combination. Tissue reaction to the polyethylene particles cannot be the cause of aseptic loosening of the stem

Aims

We aimed to evaluate the long-term outcome of highly cross-linked polyethylene (HXLPE) cemented acetabular components and assess whether any radiolucent lines (RLLs) which arose were progressive.

Introduction. Functional scores are used to clinically assess total hip arthroplasty (THA) and for comparative purposes in the orthopaedic literature. Previous research has highlighted patient age, gender and underlying diagnosis as potential sources of bias but comorbidity has not been considered. The Functional Comorbidity Index (FCI) is a published epidemiological tool which correlates disease with associated physical function deficit. It scores 18 conditions: one point for each, total score 0–18. Method & Results. We analysed 41 fully cemented primary THAs in patients ≤55 years at time of surgery with a minimum 10 years follow up. Past medical history was collected via thorough case note review. Patients were assessed using the SF-12 questionnaire, Harris Hip and WOMAC indexes. The study population consisted of 29 patients: 12 women, 17 men. Mean age: 45 years (range 22–53). All patients received cemented polished Corin TaperFit stem with polyethylene Ogee cup. Mean follow up 13.4 years (range 10.2–17.7). FCI scores ranged 0–3 (12 hips=0; 19 hips=1, 5 hips=2, 5 hips=4). A Pearson's product-moment correlation coefficient was calculated to assess the relationship between co-morbidity and hip function score using all three indexes. SF-12 score: Mean (M) =88.7; Standard Deviation (SD) =19.3; Range 0–166. Mean by FCI subgroup: 0=91, 1=96, 2=76.8, 3=68.6 (r=−0.407). HHS: M=83.8; SD=17.0; Range 45–100. Mean by FCI subgroup: 0=94.7; 1=88.2, 2=63.5, 3=54.6 (r= −0.813). WOMAC: M=79.1; SD=20.7; Range 34–100. Mean by FCI subgroup: 0=94.4, 1=91.72, 2=48.8, 3=37.4 (r=−0.812). Discussion & Conclusion. Satisfaction was extremely high with 98% of patients “extremely likely” to recommend this treatment to friends or family. Increasing FCI score correlated with decreasing hip function scores in all three indexes. This study suggests a strong negative correlation between patient comorbidity and hip function scores in THA patients. When comparing functional scores, particularly across patient and implant groups, adjustment for patient comorbidities should be made to ensure balanced evaluation

One concern about the fixation of HA-coated implants is the possible disintegration of the surface, with the migration of HA granules into the joint space, producing third-body wear. We report a study of six revisions of HA-coated polyethylene RM cups at 9 to 14 years after successful primary arthroplasty. In all six hips, we found HA granules embedded in the articulating surface of the polyethylene, with abrasive wear of the cup and the metal femoral head. The cup had loosened in four hips and three showed severe osteolysis of the proximal femur. Third-body wear due to HA particles from implant coating may produce severe clinical problems with few early warning signs. Further clinical, radiological and histological observations are needed to determine the possible incidence of this late complication in the various types of coating of a variety of substrates

Many different designs of total hip arthroplasty (THA) with varying performance and cost are available. The identification of those which are the most cost-effective could allow significant cost-savings. We used an established Markov model to examine the cost effectiveness of five frequently used categories of THA which differed according to bearing surface and mode of fixation, using data from the National Joint Registry for England and Wales. Kaplan–Meier analyses of rates of revision for men and women were modelled with parametric distributions. Costs of devices were provided by the NHS Supply Chain and associated costs were taken from existing studies. Lifetime costs, lifetime quality-adjusted-life-years (QALYs) and the probability of a device being cost effective at a willingness to pay £20 000/QALY were included in the models.

The differences in QALYs between different categories of implant were extremely small (<  0.0039 QALYs for men or women over the patient’s lifetime) and differences in cost were also marginal (£2500 to £3000 in the same time period). As a result, the probability of any particular device being the most cost effective was very sensitive to small, plausible changes in quality of life estimates and cost.

Our results suggest that available evidence does not support recommending a particular device on cost effectiveness grounds alone. We would recommend that the choice of prosthesis should be determined by the rate of revision, local costs and the preferences of the surgeon and patient.

Cite this article: Bone Joint J 2015;97-B:449–57.

Aims

The long-term functional outcome of total hip arthroplasty (THA) performed by trainees is not known. A multicentre retrospective study of 879 THAs was undertaken to investigate any differences in outcome between those performed by trainee surgeons and consultants.

Cemented femoral stems with force closed fixation designs have shown good clinical results despite high early subsidence. A new triple-tapered stem in this category (C-stem AMT) was introduced in 2005. This study compares this new stem with an established stem of similar design (Exeter) in terms of migration (as measured using radiostereometric analysis), peri-prosthetic bone remodelling (measured using dual energy x-ray densitometry, DXA), Oxford Hip Score, and plain radiographs.

A total of 70 patients (70 hips) with a mean age of 66 years (53 to 78) were followed for two years. Owing to missing data of miscellaneous reasons, the final analysis represents data from 51 (RSA) and 65 (DXA) patients. Both stems showed a typical pattern of migration: Subsidence and retroversion that primarily occurred during the first three months. C-stem AMT subsided less during the first three months (p = 0.01), before stabilising at a subsidence rate similar to the Exeter stem from years one to two. The rate of migration into retroversion was slightly higher for C-stem AMT during the second year (p = 0.03). Whilst there were slight differences in movement patterns between the stems, the C-stem AMT exhibits good early clinical outcomes and displays a pattern of migration and bone remodelling that predicts good clinical performance.

Cite this article: Bone Joint J 2015;97-B:755–61.

We assessed the orientation of the acetabular component in 1070 primary total hip arthroplasties with hard-on-soft, small diameter bearings, aiming to determine the size and site of the target zone that optimises outcome. Outcome measures included complications, dislocations, revisions and ΔOHS (the difference between the Oxford Hip Scores pre-operatively and five years post-operatively). A wide scatter of orientation was observed (2sd 15°). Placing the component within Lewinnek’s zone was not associated withimproved outcome. Of the different zone sizes tested (± 5°, ± 10° and ± 15°), only ± 15° was associated with a decreased rate of dislocation. The dislocation rate with acetabular components inside an inclination/anteversion zone of 40°/15° ± 15° was four times lower than those outside. The only zone size associated with statistically significant and clinically important improvement in OHS was ± 5°. The best outcomes (ΔOHS > 26) were achieved with a 45°/25° ± 5° zone.

This study demonstrated that with traditional technology surgeons can only reliably achieve a target zone of ±15°. As the optimal zone to diminish the risk of dislocation is also ±15°, surgeons should be able to achieve this. This is the first study to demonstrate that optimal orientation of the acetabular component improves the functional outcome. However, the target zone is small (± 5°) and cannot, with current technology, be consistently achieved.

Cite this article: Bone Joint J 2015;97-B:164–72.