Aims. The aim of the study was to investigate whether the primary stability of press-fit acetabular components can be improved by altering the impaction procedure. Methods. Three impaction procedures were used to implant acetabular components into human cadaveric acetabula using a powered impaction device. An impaction frequency of 1 Hz until complete component seating served as reference. Overimpaction was simulated by adding ten strokes after complete component seating. High-frequency implantation was performed at 6 Hz. The lever-out moment of the acetabular components was used as measure for primary stability. Permanent bone deformation was assessed by comparison of double micro-CT (µCT) measurements before and after impaction. Acetabular component deformation and impaction forces were recorded, and the extent of bone-implant contact was determined from 3D laser scans. Results. Overimpaction reduced primary acetabular component stability (p = 0.038) but did not significantly increase strain release after implantation (p = 0.117) or plastic deformations (p = 0.193). Higher press-fits were associated with larger polar gaps for the 1 Hz reference impaction (p = 0.002, R. 2. = 0.77), with a similar trend for overimpaction (p = 0.082, R. 2. = 0.31). High-frequency impaction did not significantly increase primary stability (p = 0.170) at lower impaction forces (p = 0.001); it was associated with smaller plastic deformations (p = 0.035, R. 2. = 0.34) and a trend for increased acetabular component relaxation between strokes (p = 0.112). Higher press-fit was not related to larger polar gaps for the 6 Hz impaction (p = 0.346). Conclusion. Overimpaction of press-fit acetabular components should be prevented since additional strokes can be associated with increased bone damage and reduced primary stability as shown in this study. High-frequency impaction at 6 Hz was shown to be beneficial compared with 1 Hz impaction. This benefit has to be confirmed in clinical studies. Cite this article: Bone Joint J 2023;105-B(3):261–268

Aims. It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. Methods. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. Results. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. Conclusion. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation. Cite this article: Bone Jt Open 2024;5(3):154–161

Aims. It is important to analyze objectively the hammering sound in cup press-fit technique in total hip arthroplasty (THA) in order to better understand the change of the sound during impaction. We hypothesized that a specific characteristic would present in a hammering sound with successful fixation. We designed the study to quantitatively investigate the acoustic characteristics during cementless cup impaction in THA. Methods. In 52 THAs performed between November 2018 and April 2022, the acoustic parameters of the hammering sound of 224 impacts of successful press-fit fixation, and 55 impacts of unsuccessful press-fit fixation, were analyzed. The successful fixation was defined if the following two criteria were met: 1) intraoperatively, the stability of the cup was retained after manual application of the torque test; and 2) at one month postoperatively, the cup showed no translation on radiograph. Each hammering sound was converted to sound pressures in 24 frequency bands by fast Fourier transform analysis. Basic patient characteristics were assessed as potential contributors to the hammering sound. Results. The median sound pressure (SP) of successful fixation at 0.5 to 1.0 kHz was higher than that of unsuccessful fixation (0.0694 (interquartile range (IQR) 0.04721 to 0.09576) vs 0.05425 (IQR 0.03047 to 0.06803), p < 0.001). The median SP of successful fixation at 3.5 to 4.0 kHz and 4.0 to 4.5 kHz was lower than that of unsuccessful fixation (0.0812 (IQR 0.05631 to 0.01161) vs 0.1233 (IQR 0.0730 to 0.1449), p < 0.001; and 0.0891 (IQR 0.0526 to 0.0891) vs 0.0885 (IQR 0.0716 to 0.1048); p < 0.001, respectively). There was a statistically significant positive relationship between body weight and SP at 0.5 to 1.0 kHz (p < 0.001). Multivariate analyses indicated that the SP at 0.5 to 1.0 kHz and 3.5 to 4.0 kHz was independently associated with the successful fixation. Conclusion. The frequency bands of 0.5 to 1.0 and 3.5 to 4.0 kHz were the key to distinguish the sound characteristics between successful and unsuccessful press-fit cup fixation. Cite this article: Bone Jt Open 2024;4(3):154–161

Aims. Periprosthetic fracture and implant loosening are two of the major reasons for revision surgery of cementless implants. Optimal implant fixation with minimal bone damage is challenging in this procedure. This pilot study investigates whether vibratory implant insertion is gentler compared to consecutive single blows for acetabular component implantation in a surrogate polyurethane (PU) model. Methods. Acetabular components (cups) were implanted into 1 mm nominal under-sized cavities in PU foams (15 and 30 per cubic foot (PCF)) using a vibratory implant insertion device and an automated impaction device for single blows. The impaction force, remaining polar gap, and lever-out moment were measured and compared between the impaction methods. Results. Impaction force was reduced by 89% and 53% for vibratory insertion in 15 and 30 PCF foams, respectively. Both methods positioned the component with polar gaps under 2 mm in 15 PCF foam. However, in 30 PCF foam, the vibratory insertion resulted in a clinically undesirable polar gap of over 2 mm. A higher lever-out moment was achieved with the consecutive single blow insertion by 42% in 15 PCF and 2.7 times higher in 30 PCF foam. Conclusion. Vibratory implant insertion may lower periprosthetic fracture risk by reducing impaction forces, particularly in low-quality bone. Achieving implant seating using vibratory insertion requires adjustment of the nominal press-fit, especially in denser bone. Further preclinical testing on real bone tissue is necessary to assess whether its viscoelasticity in combination with an adjusted press-fit can compensate for the reduced primary stability after vibratory insertion observed in this study. Cite this article: Bone Joint Res 2024;13(6):272–278

The need for supplementary screw fixation in acetabular revisions is still widely debated. We carried out 439 acetabular revisions over an eight-year period. In 171 hips with contained or small segmental defects, the Morscher press-fit cup was used. These revisions were followed prospectively. No screws were used for additional fixation. A total of 123 hips with a mean follow-up of 7.4 years (5 to 10.5) were available for clinical and radiological review. There was no further revision of a press-fit cup for aseptic loosening. Radiological assessment revealed osteolysis in three hips. Of the original 171 hips there was cranial and medial migration of up to 6 mm at two years in 44 (26%). No further migration was seen after the second post-operative year. Acetabular revision without screws is possible with excellent medium-term results in well selected patients

Between 1990 and 1992, we implanted 71 hybrid alumina-on-alumina hip arthroplasties in 62 consecutive patients under the age of 55 years, with a mean age of 46 years at surgery. There were 56 primary and 15 secondary procedures. The prostheses involved a cemented titanium alloy stem, a 32 mm alumina head, and a press-fit metal-backed socket with an alumina insert. Three patients (four hips) died from unrelated causes. Four hips had revision surgery for either deep infection, unexplained persistent pain, fracture of the alumina head, or aseptic loosening of the socket. The nine-year survival rate was 93.7% with revision for any cause as the end-point and 98.4% with revision for aseptic loosening as the end-point. The outcome in the surviving patients (50 patients, 57 hips) with a minimum five-year follow-up (mean eight years) was excellent in 47 hips (82.5%), very good in eight (14%), good in one and fair in one. A thin, partial, lucent line, mainly in zone III was present in 38% of the sockets and one socket had a complete lucency less than 1 mm thick. One stem had isolated femoral osteolysis. There was no detectable component migration nor acetabular osteolysis. This hybrid arthroplasty gave satisfactory medium-term results in active patients. The press-fit metal-backed socket appeared to have reliable fixation in alumina-on-alumina hip arthroplasty. The excellent results using cemented fixation of the stem may be related to the low production of wear debris

We retrospectively reviewed, ten years after surgery, 100 consecutive total hip replacements in which the Duraloc 300 cup had been used. Post-operative radiographs were analysed for placement of the cup and interface gaps and follow-up radiographs for lucent lines, osteolysis, wear and migration.

All the components were found to be stable with no evidence of loosening. The mean rate of wear was 0.12 mm/year. Three hips developed acetabular osteolysis at the level of the apex hole. Two have successfully undergone bone grafting without removal of the implants and one patient is awaiting surgery. The Duraloc 300 cup has a survival of 100% at ten years with no aseptic loosening and a low incidence of pelvic osteolysis.

Aims. Highly polished stems with force-closed design have shown satisfactory clinical results despite being related to relatively high early migration. It has been suggested that the minimal thickness of cement mantles surrounding the femoral stem should be 2 mm to 4 mm to avoid aseptic loosening. The line-to-line cementing technique of the femoral stem, designed to achieve stem press-fit, challenges this opinion. We compared the migration of a highly polished stem with force-closed design by standard and line-to-line cementing to investigate whether differences in early migration of the stems occur in a clinical study. Methods. In this single-blind, randomized controlled, clinical radiostereometric analysis (RSA) study, the migration pattern of the cemented Corail hip stem was compared between line-to-line and standard cementing in 48 arthroplasties. The primary outcome measure was femoral stem migration in terms of rotation and translation around and along with the X-, Y-, and Z- axes measured using model-based RSA at three, 12, and 24 months. A linear mixed-effects model was used for statistical analysis. Results. Results from mixed model analyses revealed a lower mean retroversion for line-to-line (0.72° (95% confidence interval (CI) 0.38° to 1.07°; p < 0.001), but no significant differences in subsidence between the techniques (-0.15 mm (95% CI -0.53 to 0.227; p = 0.429) at 24 months. Radiolucent lines measuring < 2 mm wide were found in three and five arthroplasties cemented by the standard and line-to-line method, respectively. Conclusion. The cemented Corail stem with a force-closed design seems to settle earlier and better with the line-to-line cementing method, although for subsidence the difference was not significant. However, the lower rate of migration into retroversion may reduce the wear and cement deformation, contributing to good long-term fixation and implant survival. Cite this article: Bone Joint J 2022;104-B(1):19–26

Aims. Cementless acetabular components rely on press-fit fixation for initial stability. In certain cases, initial stability is more difficult to obtain (such as during revision). No current study evaluates how a surgeon’s impaction technique (mallet mass, mallet velocity, and number of strikes) may affect component fixation. This study seeks to answer the following research questions: 1) how does impaction technique affect a) bone strain generation and deterioration (and hence implant stability) and b) seating in different density bones?; and 2) can an impaction technique be recommended to minimize risk of implant loosening while ensuring seating of the acetabular component?. Methods. A custom drop tower was used to simulate surgical strikes seating acetabular components into synthetic bone. Strike velocity and drop mass were varied. Synthetic bone strain was measured using strain gauges and stability was assessed via push-out tests. Polar gap was measured using optical trackers. Results. A phenomenon of strain deterioration was identified if an excessive number of strikes was used to seat a component. This effect was most pronounced in low-density bone at high strike velocities. Polar gap was reduced with increasing strike mass and velocity. Conclusion. A high mallet mass with low strike velocity resulted in satisfactory implant stability and polar gap, while minimizing the risk of losing stability due to over-striking. Extreme caution not to over-strike must be exercised when using high velocity strikes in low-density bone for any mallet mass. Cite this article: Bone Joint Res 2020;9(7):386–393

Objectives. Modular junctions are ubiquitous in contemporary hip arthroplasty. The head-trunnion junction is implicated in the failure of large diameter metal-on-metal (MoM) hips which are the currently the topic of one the largest legal actions in the history of orthopaedics (estimated costs are stated to exceed $4 billion). Several factors are known to influence the strength of these press-fit modular connections. However, the influence of different head sizes has not previously been investigated. The aim of the study was to establish whether the choice of head size influences the initial strength of the trunnion-head connection. Materials and Methods. Ti-6Al-4V trunnions (n = 60) and two different sizes of cobalt-chromium (Co-Cr) heads (28 mm and 36 mm; 30 of each size) were used in the study. Three different levels of assembly force were considered: 4 kN; 5 kN; and 6 kN (n = 10 each). The strength of the press-fit connection was subsequently evaluated by measuring the pull-off force required to break the connection. The statistical differences in pull-off force were examined using a Kruskal–Wallis test and two-sample Mann–Whitney U test. Finite element and analytical models were developed to understand the reasons for the experimentally observed differences. Results. 36 mm diameter heads had significantly lower pull-off forces than 28 mm heads when impacted at 4 kN and 5 kN (p < 0.001; p < 0.001), but not at 6 kN (p = 0.21). Mean pull-off forces at 4 kN and 5 kN impaction forces were approximately 20% larger for 28 mm heads compared with 36 mm heads. Finite element and analytical models demonstrate that the differences in pull-off strength can be explained by differences in structural rigidity and the resulting interface pressures. Conclusion. This is the first study to show that 36 mm Co-Cr heads have up to 20% lower pull-off connection strength compared with 28 mm heads for equivalent assembly forces. This effect is likely to play a role in the high failure rates of large diameter MoM hips. Cite this article: A. R. MacLeod, N. P. T. Sullivan, M. R. Whitehouse, H. S. Gill. Large-diameter total hip arthroplasty modular heads require greater assembly forces for initial stability. Bone Joint Res 2016;5:338–346. DOI: 10.1302/2046-3758.58.BJR-2016-0044.R1

Aims

Instability is a common cause of failure after total hip arthroplasty. A novel reverse total hip has been developed, with a femoral cup and acetabular ball, creating enhanced mechanical stability. The purpose of this study was to assess the implant fixation using radiostereometric analysis (RSA), and the clinical safety and efficacy of this novel design.

Aims

Manual impaction, with a mallet and introducer, remains the standard method of installing cementless acetabular cups during total hip arthroplasty (THA). This study aims to quantify the accuracy and precision of manual impaction strikes during the seating of an acetabular component. This understanding aims to help improve impaction surgical techniques and inform the development of future technologies.

Aims

Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction.

Aims

Transfusion after primary total hip arthroplasty (THA) has become rare, and identification of causative factors allows preventive measures. The aim of this study was to determine patient-specific factors that increase the risk of needing a blood transfusion.

Aims

This study reports the results of 38 total hip arthroplasties (THAs) in 33 patients aged less than 50 years, using the JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component.

Aims

The primary aim of this trial was to compare the subsidence of two similar hydroxyapatite-coated titanium femoral components from different manufacturers. Secondary aims were to compare rotational migration (anteversion/retroversion and varus/valgus tilt) and patient-reported outcome measures between both femoral components.

Aims

Several short- and mid-term studies have shown minimal liner wear of highly cross-linked polyethylene (HXLPE) in total hip arthroplasty (THA), but the safety of using thinner HXLPE liners to maximize femoral head size remains uncertain. The objective of this study was to analyze clinical survival and radiological wear rates of patients with HXLPE liners, a 36 mm femoral head, and a small acetabular component with a minimum of ten years’ follow-up.

Aims

The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy.

We have undertaken a prospective, randomised study to compare conservation of acetabular bone after total hip replacement and resurfacing arthroplasty of the hip. We randomly assigned 210 hips to one of the two treatment groups. Uncemented, press-fit acetabular components were used for both. No significant difference was found in the mean diameter of acetabular implant inserted in the groups (54.74 mm for total hip replacement and 54.90 mm for resurfacing arthroplasty). In seven resurfacing procedures (6.8%), the surgeon used a larger size of component in order to match the corresponding diameter of the femoral component. With resurfacing arthroplasty, conservation of bone is clearly advantageous on the femoral side. Our study has shown that, with a specific design of acetabular implant and by following a careful surgical technique, removal of bone on the acetabular side is comparable with that of total hip replacement

Aims

The aim of this study was to examine the implant accuracy of custom-made partial pelvis replacements (PPRs) in revision total hip arthroplasty (rTHA). Custom-made implants offer an option to achieve a reconstruction in cases with severe acetabular bone loss. By analyzing implant deviation in CT and radiograph imaging and correlating early clinical complications, we aimed to optimize the usage of custom-made implants.

Cementless acetabular fixation has demonstrated superior long-term durability in total hip replacement, but most series have studied implants with porous metal surfaces. We retrospectively evaluated the results of 100 consecutive patients undergoing total hip replacement where a non-porous Allofit component was used for primary press-fit fixation. This implant is titanium alloy, grit-blasted, with a macrostructure of forged teeth and has a biradial shape. A total of 81 patients (82 hips) were evaluated at final follow-up at a mean of 10.1 years (8.9 to 11.9). The Harris Hip Score improved from a mean 53 points (23 to 73) pre-operatively to a mean of 96 points (78 to 100) at final review. The osseointegration of all acetabular components was radiologically evaluated with no evidence of loosening. The survival rate with revision of the component as the endpoint was 97.5% (95% confidence interval 94 to 100) after 11.9 years. Radiolucency was found in one DeLee-Charnley zone in four acetabular components. None of the implants required revision for aseptic loosening. Two patients were treated for infection, one requiring a two-stage revision of the implant. One femoral stem was revised for osteolysis due to the production of metal wear debris, but the acetabular shell did not require revision. This study demonstrates that a non-porous titanium acetabular component with adjunct surface fixation offers an alternative to standard porous-coated implants

We assessed differences in the incidence and appearance of the radiological signs of loosening of the cup for various types of design. This was an observational study based on hip registry data of 15 340 patients with 17 951 total hip arthroplasties collected over a period of 33 years in 49 hospitals in Central Europe. The threaded and the press-fit titanium cups showed significantly less aseptic loosening than the other systems. The direction of migration and the frequency of the radiological signs of loosening differed between the cup systems and were time-dependent. Our findings indicate the superiority of uncemented threaded cups and press-fit titanium cups over other designs of cup

Aims

A significant reduction in wear at five and ten years was previously reported when comparing Durasul highly cross-linked polyethylene with nitrogen-sterilized Sulene polyethylene in total hip arthroplasty (THA). We investigated whether the improvement observed at the earlier follow-up continued, resulting in decreased osteolysis and revision surgery rates over the second decade.

We reviewed the results at nine to 13 years of 125 total hip replacements in 113 patients using the monoblock uncemented Morscher press-fit acetabular component. The mean age at the time of operation was 56.9 years (36 to 74). The mean clinical follow-up was 11 years (9.7 to 13.5) and the mean radiological follow-up was 9.4 years (7.7 to 13.1). Three hips were revised, one immediately for instability, one for excessive wear and one for deep infection. No revisions were required for aseptic loosening. A total of eight hips (7.0%) had osteolytic lesions greater than 1 cm, in four around the acetabular component (3.5%). One required bone grafting behind a well-fixed implant. The mean wear rate was 0.11 mm/year (0.06 to 0.78) and was significantly higher in components with a steeper abduction angle. Kaplan-Meier survival curves at 13 years showed survival of 96.8% (95% confidence interval 90.2 to 99.0) for revision for any cause and of 95.7% (95% confidence interval 88.6 to 98.4) for any acetabular re-operation

We carried out 71 primary total hip arthroplasties using porous-coated, hemispherical press-fit Duraloc ‘100 Series’ cups in 68 consecutive patients; 61 were combined with the cementless Spotorno stem and ten with the cemented Lubinus SP II stem. Under-reaming of 2 mm achieved a press-fit. Of the 71 hips, 69 (97.1%) were followed up after a mean of 2.4 years. Migration analysis was performed by the Ein Bild Röntgen Analyse method, with an accuracy of 1 mm. The mean total migration after 24 months was 1.13 mm. Using the definition of loosening as a total migration of 1 mm, it follows that 30 out of 63 cups (48%) were loose at 24 months

We carried out a clinical and radiological review of 103 cementless primary hip arthroplasties with a tapered rectangular grit-blasted titanium press-fit femoral component and a threaded conical titanium acetabular component at a mean follow-up of 14.4 years (10.2 to 17.1). The mean Harris hip score at the last follow-up was 89.2 (32 to 100). No early loosening and no fracture of the implant were found. One patient needed revision surgery because of a late deep infection. In 11 hips (10.7%), the reason for revision was progressive wear of the polyethylene liner. Exchange of the acetabular component because of aseptic loosening without detectable liner wear was carried out in three hips (2.9%). After 15 years the survivorship with aseptic loosening as the definition for failure was 95.6% for the acetabular component and 100% for the femoral component

Aims

Adult patients with history of childhood infection pose a surgical challenge for total hip arthroplasty (THA) due to distorted bony anatomy, soft-tissue contractures, risk of reinfection, and relatively younger age. Therefore, the purpose of the present study was to determine clinical outcome, reinfection rate, and complications in patients with septic sequelae after THA.

The Morscher-Spotorno (MS-30) femoral stem is a stainless-steel, straight, three-dimensionally tapered, collarless implant for cemented fixation in total hip replacement. We report the results at ten years of a consecutive series of 124 total hip replacements in 121 patients with the matt-surfaced MS-30 stem and an alumina ceramic head of 28-mm diameter. All the stems were fixed with Palacos bone cement with gentamicin using a modern cementing technique. They were combined with an uncemented, press-fit cup. The mean period of observation was 10.2 years (8.3 to 12.1) and no patient was lost to follow-up. Twenty-seven patients (22%) died with the implant in situ. Nine could only be interviewed by telephone. We included 85 patients with 88 hips in the clinical and radiological follow-up examinations. None of the stems or cups had been revised. The Harris hip score was excellent or good in 97% (85 hips) and moderate in 3% (three hips). Radiologically, six hips (6.8%) had osteolysis adjacent to the stem, mostly in Gruen zone 7. Twenty (22.7%) showed one or more radiolucent lines. Twenty-two stems (25%) had subsided by 2 mm to 5 mm. In these cases two showed osteolysis (9.1%) with subsidence and four without (6.1%). Radiolucent lines were seen in seven with migration (31.8%) and in 13 without (19.7%). No infections and no acetabular osteolysis were observed. The clinical results were excellent with survivorship after ten years of 100% and only a slightly statistically non-significant higher rate of osteolysis and radiolucency in cases of subsidence

Aims

Periprosthetic hip fractures (PPFs) after total hip arthroplasty are difficult to treat. Therefore, it is important to identify modifiable risk factors such as stem selection to reduce the occurrence of PPFs. This study aimed to clarify differences in fracture torque, surface strain, and fracture type analysis between three different types of cemented stems.

Aims

The aim of this study was to determine whether total hip arthroplasty (THA) for chronic hip pain due to unilateral primary osteoarthritis (OA) has a beneficial effect on cognitive performance.

Aims

The aim of this study was to evaluate the performance of first-generation annealed highly cross-linked polyethylene (HXLPE) in cementless total hip arthroplasty (THA).

Aims

To achieve the functional benefits of the direct anterior (DA) approach and the fixation benefits of cemented replacement, this study combined the two techniques posing the following questions: does the limited access of the DA approach adversely affect the cement technique?; and does such a cementing technique reduce the incidence of cementless complications?

Aims

Highly cross-linked polyethylene (HXLPE) has greatly improved the durability of total hip arthroplasty (THA) in young patients because of its improved wear characteristics. Few studies have followed this population into the second decade, and therefore the purpose of this investigation was to evaluate the clinical outcome for THA patients 50 years of age and younger at a minimum of 15 years postoperatively. The second purpose was to evaluate the radiological findings secondary to wear or mechanical failure of the implant.

Aims

We aimed to investigate if the use of the largest possible cobalt-chromium head articulating with polyethylene acetabular inserts would increase the in vivo wear rate in total hip arthroplasty.

Aims

Use of the direct anterior approach (DAA) for total hip arthroplasty (THA) has increased in recent years due to proposed benefits, including a lower risk of dislocation and improved early functional recovery. This study investigates the dislocation rate in a non-selective, consecutive cohort undergoing THA via the DAA without any exclusion or bias in patient selection based on habitus, deformity, age, sex, or fixation method.

Aims

The aim of this prospective cohort study was to evaluate the early migration of the TriFit cementless proximally coated tapered femoral stem using radiostereometric analysis (RSA).

Aims

We present the clinical and radiological results at a minimum follow-up of 20 years using a second-generation uncemented total hip arthroplasty (THA). These results are compared to our previously published results using a first-generation hip arthroplasty followed for 20 years.

We report the radiological and clinical outcome of a press-fit (SLF) acetabular component at two to three years in two groups of patients having primary total hip replacement. In 69 the implant was coated with hydroxyapatite (HA) and in 40 it was uncoated. The stability of the cup was assessed by measurement of proximal migration and change in the angle of inclination. The clinical results in the two groups did not differ significantly, and the mean proximal linear wear was similar in both. Fewer radiolucent lines (RLLs) were seen on the radiographs of cups coated with HA. The mean proximal migration was studied by calculating regression lines for each patient using migration measurements: for the SLF+HA group the mean slope was 0.06 mm/year and for the SLF–HA group 0.20 mm/year (p = 0.22). The change in the angle of inclination during follow-up was also consistently smaller in HA–coated cups. Using regression methods the SLF+HA group had a mean slope of 0.08°/year and the SLF-HA group 0.44°/year (p = 0.023). Partial HA coating appeared to have no effect on the clinical outcome or on the rate of wear of polyethylene, but there was a trend towards a reduced rate of proximal migration, and a significant reduction in rotational migration and the number of radiolucent lines. This suggests that HA coating enhances the stability of this acetabular component

After an allogenic bone-marrow transplant, a vascular necrosis of the femoral head may affect young adults, producing destructive lesions which require hip replacement. We have reviewed 27 consecutive such total hip arthroplasties (THA) at a minimal follow-up of two years. Of these, 20 were primary operations for Ficat (1985) stage-III and stage-IV lesions, and seven were revisions after the failure of previous surgery. The median age at operation was 30 years (17.5 to 44). The prostheses had a cemented, collared titanium-alloy stem, an alumina-alumina joint, and a press-fit socket. Seven had a titanium-alloy metal back and 20 had all-alumina cups of which six had to be cemented. At an average follow-up of five years, no patient had been lost to follow-up. One had died from septicaemia after two years and another with chronic graft-versus-host disease developed a deep infection 2.5 years postoperatively and had a successful revision. There were no revisions for aseptic loosening. The clinical results on the Merle d’Aubigné and Postel (1954) scale were very good or excellent in 23 hips (88%), good in one and fair in two. Ten hips showed incomplete acetabular radiolucencies less than 1 mm thick, but there were no radiolucent lines around the stems. We conclude that for these difficult patients THA with ceramic joints and careful technique provides the best short- and medium-term option after the failure of medical treatment

Aims

Short, bone-conserving femoral components are increasingly used in total hip arthroplasty (THA). They are expected to allow tissue-conserving implantation and to render future revision surgery more straightforward but the long-term data on such components is limited. One such component is the global tissue-sparing (GTS) stem. Following the model for stepwise introduction of new orthopaedic implants, we evaluated early implant fixation and clinical outcome of this novel short-stem THA and compared it to that of a component with established good long-term clinical outcome.

Aims

We evaluated a large database with mechanical failure of a single uncemented modular femoral component, used in revision hip arthroplasty, as the end point and compared them to a control group treated with the same implant. Patient- and implant-specific risk factors for implant failure were analyzed.

We reviewed a consecutive series of 527 uninfected hip replacements in patients resident in the UK which had been implanted from 1981 to 1993. All had the same basic design of femoral prosthesis, but four fixation techniques had been used: two press-fit, one HA-coated and one cemented. Review and radiography were planned prospectively. For assessment the components were retrospectively placed into two groups: those which had failed from two years onwards by aseptic femoral loosening and those in which the femoral component had survived without revision or recommendation for revision. All available radiographs in both groups were measured to determine vertical migration and examined by two observers to agree the presence of radiolucent lines (RLLs), lytic lesions, resorption of the neck, proximal osteopenia and distal intramedullary and distal subperiosteal formation of new bone. We then related the presence or absence of these features and the rate of migration at two years to the outcome with regard to aseptic loosening and determined the predictive value of each of these variables. Migration of ≥2 mm at two years, the presence of an RLL of 2 mm occupying one-third of any one zone, and subperiosteal formation of new bone at the tip of the stem were predictors of aseptic loosening after two years. There were too few lytic lesions to assess at two years, but at five years a lytic lesion ≥2 mm also predicted failure. We discuss the use of these variables as predictors of femoral aseptic loosening for groups of hips and for individual hips. We conclude that if a group of about 50 total hip replacements, perhaps with a new design of femoral stem, were studied in this way at two years, a mean migration of < 0.4 mm and an incidence of < 10% of RLLs of 2 mm in any one zone would predict 95% survival at ten years. For an individual prosthesis, migration of < 2 mm and the absence of an RLL of ≤2 mm at two years predict a 6% chance of revision over approximately ten years. If either 2 mm of migration or an RLL of 2 mm is present, the chances of revision rise to 27%, and if both radiological signs are present they are 50%. If at five years a lytic lesion has developed, whatever the situation at two years, there is approximately a 50% chance of failure in the following five years. Our findings suggest that replacements using a limited number of any new design of femoral prosthesis should be screened radiologically at two years before they are generally introduced. We also suggest that radiographs of individual patients at two years and perhaps at five years should be studied to help to decide whether or not the patient should remain under close review or be discharged from specialist follow-up

Aims

This single-centre observational study aimed to describe the results of extensive bone impaction grafting of the whole acetabular cavity in combination with an uncemented component in acetabular revisions performed in a standardized manner since 1993.

Aims

Vitamin E-diffused, highly crosslinked polyethylene (VEPE) and porous titanium-coated (PTC) shells were introduced in total hip arthroplasty (THA) to reduce the risk of aseptic loosening. The purpose of this study was: 1) to compare the wear properties of VEPE to moderately crosslinked polyethylene; 2) to assess the stability of PTC shells; and 3) to report their clinical outcomes at seven years.

Objectives

Modern metal-on-metal (MoM) hip resurfacing arthroplasty (HRA), while achieving good results with well-orientated, well-designed components in ideal patients, is contraindicated in women, men with head size under 50 mm, or metal hypersensitivity. These patients currently have no access to the benefits of HRA. Highly crosslinked polyethylene (XLPE) has demonstrated clinical success in total hip arthroplasty (THA) and, when used in HRA, potentially reduces metal ion-related sequelae. We report the early performance of HRA using a direct-to-bone cementless mono-bloc XLPE component coupled with a cobalt-chrome femoral head, in the patient group for whom HRA is currently contraindicated.

Aims

We compared implant and patient survival following intraoperative periprosthetic femoral fractures (IOPFFs) during primary total hip arthroplasty (THA) with matched controls.

Aims

The aim of this study was to estimate the 90-day risk of revision for periprosthetic femoral fracture associated with design features of cementless femoral stems, and to investigate the effect of a collar on this risk using a biomechanical in vitro model.

Aims

Modular dual-mobility constructs reduce the risk of dislocation after revision total hip arthroplasty (THA). However, questions about metal ions from the cobalt-chromium (CoCr) liner persist, and are particularly germane to patients being revised for adverse local tissue reactions (ALTR) to metal. We determined the early- to mid-term serum Co and Cr levels after modular dual-mobility components were used in revision and complex primary THAs, and specifically included patients revised for ALTR.

Aims

The purpose of this study was to evaluate the biological fixation of a 3D printed porous implant, with and without different hydroxyapatite (HA) coatings, in a canine model.

Objectives

In order to address acetabular defects, porous metal revision acetabular components and augments have been developed, which require fixation to each other. The fixation technique that results in the smallest relative movement between the components, as well as its influence on the primary stability with the host bone, have not previously been determined.

Aims

We previously reported the long-term results of the cementless Duraloc-Profile total hip arthroplasty (THA) system in a 12- to 15-year follow-up study. In this paper, we provide an update on the clinical and radiological results of a previously reported cohort of patients at 23 to 26 years´ follow-up.

Aims

The use of trabecular metal (TM) shells supported by augments has provided good mid-term results after revision total hip arthroplasty (THA) in patients with a bony defect of the acetabulum. The aim of this study was to assess the long-term implant survivorship and radiological and clinical outcomes after acetabular revision using this technique.

Aims

The purpose of this exploratory study was to investigate if the 24-hour activity profile (i.e. waking activities and sleep) objectively measured using wrist-worn accelerometry of patients scheduled for total hip arthroplasty (THA) improves postoperatively.

Aims

Instability continues to be a troublesome complication after total hip arthroplasty (THA). Patient-related risk factors associated with a higher dislocation risk include the preoperative diagnosis, an age of 75 years or older, high body mass index (BMI), a history of alcohol abuse, and neurodegenerative diseases. The goal of this study was to assess the dislocation rate, radiographic outcomes, and complications of patients stratified as high-risk for dislocation who received a dual mobility (DM) bearing in a primary THA at a minimum follow-up of two years.

Aims

Cementless femoral stems must be correctly sized and well-seated to obtain satisfactory biological fixation. The change in sound that occurs during impaction of the femoral broach is said to indicate good fit, but this has not been widely studied. We set out to find whether the presence or absence of these sound changes could predict correct sizing.

Aims

Severe acetabular bone loss and pelvic discontinuity (PD) present particular challenges in revision total hip arthroplasty. To deal with such complex situations, cup-cage reconstruction has emerged as an option for treating this situation. We aimed to examine our success in using this technique for these anatomical problems.

Aims

To determine the effect of a change in design of a cementless ceramic acetabular component in fixation and clinical outcome after total hip arthroplasty

Aims

This study reports the mid-term results of total hip arthroplasty (THA) performed using a monoblock acetabular component with a large-diameter head (LDH) ceramic-on-ceramic (CoC) bearing.

Aims

Our aim was to evaluate the radiographic characteristics of patients undergoing total hip arthroplasty (THA) for the potential of posterior bony impingement using CT simulations.

Aims

To evaluate the hypothesis that failed osteosynthesis of periprosthetic Vancouver type B1 fractures can be treated successfully with stem revision using a transfemoral approach and a cementless, modular, tapered revision stem with reproducible rates of fracture healing, stability of the revision stem, and clinically good results.

Patients with neuromuscular imbalance who require total hip arthroplasty (THA) present particular technical problems due to altered anatomy, abnormal bone stock, muscular imbalance and problems of rehabilitation.

In this systematic review, we studied articles dealing with THA in patients with neuromuscular imbalance, published before April 2017. We recorded the demographics of the patients and the type of neuromuscular pathology, the indication for surgery, surgical approach, concomitant soft-tissue releases, the type of implant and bearing, pain and functional outcome as well as complications and survival.

Recent advances in THA technology allow for successful outcomes in these patients. Our review suggests excellent benefits for pain relief and good functional outcome might be expected with a modest risk of complication.

Cite this article: Bone Joint J 2018;100-B(1 Supple A):17–21.

Aims

One method of femoral head preservation following avascular necrosis (AVN) is core decompression and insertion of a tantalum rod. However, there may be a high failure rate associated with this procedure. The purpose of this study was to document the clinical and radiological outcomes following total hip arthroplasty (THA) subsequent to failed tantalum rod insertion.

Concerns have been raised that deformation of acetabular shells may disrupt the assembly process of modular prostheses. In this study we aimed to examine the effect that the strength of bone has on the amount of deformation of the acetabular shell. The hypothesis was that stronger bone would result in greater deformation. A total of 17 acetabular shells were inserted into the acetabula of eight cadavers, and deformation was measured using an optical measuring system. Cores of bone from the femoral head were taken from each cadaver and compressed using a materials testing machine. The highest peak modulus and yield stress for each cadaver were used to represent the strength of the bone and compared with the values for the deformation and the surgeon’s subjective assessment of the hardness of the bone. The mean deformation of the shell was 129 µm (3 to 340). No correlation was found between deformation and either the maximum peak modulus (r² = 0.011, t = 0.426, p = 0.676) or the yield stress (r² = 0.024, t = 0.614, p = 0.549) of the bone. Although no correlation was found between the strength of the bone and deformation, the values for the deformation observed could be sufficient to disrupt the assembly process of modular acetabular components.

Cite this article: Bone Joint J 2015; 97-B:473–7.

Aims

The aim of this study was to identify patient- and surgery-related risk factors for sustaining an early periprosthetic fracture following primary total hip arthroplasty (THA) performed using a double-tapered cementless femoral component (Bi-Metric femoral stem; Biomet Inc., Warsaw, Indiana).

Objective

This study compared the primary stability of two commercially available acetabular components from the same manufacturer, which differ only in geometry; a hemispherical and a peripherally enhanced design (peripheral self-locking (PSL)). The objective was to determine whether altered geometry resulted in better primary stability.

This review summarises the technique of impaction grafting with mesh augmentation for the treatment of uncontained acetabular defects in revision hip arthroplasty.

The ideal acetabular revision should restore bone stock, use a small socket in the near-anatomic position, and provide durable fixation. Impaction bone grafting, which has been in use for over 40 years, offers the ability to achieve these goals in uncontained defects. The precepts of modern, revision impaction grafting are that the segmental or cavitary defects must be supported with a mesh; the contained cavity is filled with vigorously impacted morselised fresh-frozen allograft; and finally, acrylic cement is used to stabilise the graft and provide rigid, long-lasting fixation of the revised acetabular component.

Favourable results have been published with this technique. While having its limitations, it is a viable option to address large acetabular defects in revision arthroplasty.

Cite this article: Bone Joint J 2017;99-B(1 Supple A):25–30.

Objectives

In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes.

Aims

To investigate the longevity of uncemented fixation of a femoral component in total hip arthroplasty (THA) in patients with Dorr type C proximal femoral morphology.

Aims

The optimal management of intracapsular fractures of the femoral neck in independently mobile patients remains open to debate. Successful fixation obviates the limitations of arthroplasty for this group of patients. However, with fixation failure rates as high as 30%, the outcome of revision surgery to salvage total hip arthroplasty (THA) must be considered. We carried out a systematic review to compare the outcomes of salvage THA and primary THA for intracapsular fractures of the femoral neck.

We describe our technique and rationale using hybrid fixation for primary total hip arthroplasty (THA) at the Hospital for Special Surgery. Modern uncemented acetabular components have few screw holes, or no holes, polished inner surfaces, improved locking mechanisms, and maximised thickness and shell-liner conformity. Uncemented sockets can be combined with highly cross-linked polyethylene liners, which have demonstrated very low wear and osteolysis rates after ten to 15 years of implantation. The results of cement fixation with a smooth or polished surface finished stem have been excellent, virtually eliminating complications seen with cementless fixation like peri-operative femoral fractures and thigh pain. Although mid-term results of modern cementless stems are encouraging, the long-term data do not show reduced revision rates for cementless stems compared with cemented smooth stems. In this paper we review the conduct of a hybrid THA, with emphasis on pre-operative planning, surgical technique, hypotensive epidural anaesthesia, and intra-operative physiology.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):54–9.

The ideal acetabular component is characterised by reliable, long-term fixation with physiological loading of bone and a low rate of wear. Trabecular metal is a porous construct of tantalum which promotes bony ingrowth, has a modulus of elasticity similar to that of cancellous bone, and should be an excellent material for fixation.

Between 2004 and 2006, 55 patients were randomised to receive either a cemented polyethylene or a monobloc trabecular metal acetabular component with a polyethylene articular surface. We measured the peri-prosthetic bone density around the acetabular components for up to two years using dual-energy x-ray absorptiometry.

We found evidence that the cemented acetabular component loaded the acetabular bone centromedially whereas the trabecular metal monobloc loaded the lateral rim and behaved like a hemispherical rigid metal component with regard to loading of the acetabular bone. We suspect that this was due to the peripheral titanium rim used for the mechanism of insertion.

The treatment of substantial proximal femoral bone loss in young patients with developmental dysplasia of the hip (DDH) is challenging. We retrospectively analysed the outcome of 28 patients (30 hips) with DDH who underwent revision total hip replacement (THR) in the presence of a deficient proximal femur, which was reconstructed with an allograft prosthetic composite. The mean follow-up was 15 years (8.5 to 25.5). The mean number of previous THRs was three (1 to 8). The mean age at primary THR and at the index reconstruction was 41 years (18 to 61) and 58.1 years (32 to 72), respectively. The indication for revision included mechanical loosening in 24 hips, infection in three and peri-prosthetic fracture in three.

Six patients required removal and replacement of the allograft prosthetic composite, five for mechanical loosening and one for infection. The survivorship at ten, 15 and 20 years was 93% (95% confidence interval (CI) 91 to 100), 75.5% (95% CI 60 to 95) and 75.5% (95% CI 60 to 95), respectively, with 25, eight, and four patients at risk, respectively. Additionally, two junctional nonunions between the allograft and host femur required bone grafting and plating.

An allograft prosthetic composite affords a good long-term outcome in the management of proximal femoral bone loss in revision THR in patients with DDH, while preserving distal host bone.

This study reports the results of 38 total hip arthroplasties (THAs) in 33 patients aged <  50 years, using the JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component. This represents an update of previous reports of the same cohort at ten and 16 years, which were reported in 2004 and 2009, respectively. We describe the survival, radiological and functional outcomes at a mean follow-up of 21 years (17 to 25). Of the surviving 34 THAs, one underwent femoral revision for peri-prosthetic fracture after 21 years, and one patient (one hip) was lost to follow-up. Using aseptic loosening as the end-point, 12 hips (31.5%) needed acetabular revision but none needed femoral revision, demonstrating 100% survival (95% confidence interval 89 to 100).

In young patients with high demands, the Furlong HAC–coated femoral component gives excellent long-term results.

Cite this article: Bone Joint J 2015;97-B:749–54.

The long-term survival of the cementless Spotorno CLS femoral component in patients aged > 50 years at the time of arthroplasty was investigated. Survivorship analysis of a consecutive series of 85 patients (100 hips; under 50 years of age at a mean follow-up of 18.4 years (16.3 to 20.8)) was performed. The clinical and radiographic outcomes were satisfactory. The overall rate of survival of the femoral component was 93.5% (95% confidence interval (CI), 90.9 to 96.1) after 19 years. Survival with revision for aseptic loosening as the end point was 95.7% (95% CI 93.6 to 97.8%) at 19 years.

This study demonstrates an excellent long-term survival of the Spotorno CLS femoral component after 16 to 20 years in young patients undergoing total hip arthroplasty.

Cite this article: Bone Joint J 2015;97-B:160–3.

A pelvic discontinuity occurs when the superior and inferior parts of the hemi-pelvis are no longer connected, which is difficult to manage when associated with a failed total hip replacement. Chronic pelvic discontinuity is found in 0.9% to 2.1% of hip revision cases with risk factors including severe pelvic bone loss, female gender, prior pelvic radiation and rheumatoid arthritis. Common treatment options include: pelvic plating with allograft, cage reconstruction, custom triflange implants, and porous tantalum implants with modular augments. The optimal technique is dependent upon the degree of the discontinuity, the amount of available bone stock and the likelihood of achieving stable healing between the two segments. A method of treating pelvic discontinuity using porous tantalum components with a distraction technique that achieves both initial stability and subsequent long-term biological fixation is described.

Cite this article: Bone Joint J 2014;96-B(11 Suppl A):73–7.

Dysplasia of the hip, hypotonia, osteopenia, ligamentous laxity, and mental retardation increase the complexity of performing and managing patients with Down syndrome who require total hip replacement (THR). We identified 14 patients (six males, eight females, 21 hips) with Down syndrome and degenerative disease of the hip who underwent THR, with a minimum follow-up of two years from 1969 to 2009. In seven patients, bilateral THRs were performed while the rest had unilateral THRs. The mean clinical follow-up was 5.8 years (standard deviation (sd) 4.7; 2 to 17). The mean Harris hip score was 37.9 points (sd 7.8) pre-operatively and increased to 89.2 (sd 12.3) at final follow-up (p = 1x10^-9). No patient suffered a post-operative dislocation. In three patients, four hips had revision THR for aseptic loosening at a mean follow-up of 7.7 years (sd 6.3; 3 to 17). This rate of revision THR was higher than expected. Our patients with Down syndrome benefitted clinically from THR at mid-term follow-up.

Cite this article: Bone Joint J 2014;96-B:1455–8.

Between January 1998 and December 1998, 82 consecutive patients (86 hips) underwent total hip arthroplasty using a trabecular metal monoblock acetabular component. All patients had a clinical and radiological follow-up evaluation at six, 12 and 24 weeks, 12 months, and then annually thereafter. On the initial post-operative radiograph 25 hips had a gap between the outer surface of the component and the acetabular host bed which ranged from 1 to 5 mm. All patients were followed up clinically and radiologically for a mean of 7.3 years (7 to 7.5). The 25 hips with the 1 to 5 mm gaps were studied for component migration at two years using the Einzel-Bild-Roentgen-Analyse (EBRA) digital measurement method. At 24 weeks all the post-operative gaps were filled with bone and no acetabular component had migrated. The radiographic outcome of all 86 components showed no radiolucent lines and no evidence of lysis. No acetabular implant was revised. There were no dislocations or other complications. The bridging of the interface gaps (up to 5 mm) by the trabecular metal monoblock acetabular component indicates the strong osteoconductive, and possibly osteoinductive, properties of trabecular metal.

We reviewed 111 hemispherical Duraloc series-500 acetabular components with a minimum follow-up of 12 years. The mean clinical and radiological follow-up was 13.4 years (12 to 15). A Profile hydroxyapatite-coated anatomical femoral component was used in each case. Six patients had a late dislocation, for whom the polyethylene liner was exchanged. Each acetabular component was well fixed and all femoral components showed signs of bone ingrowth. The mean rate of femoral head penetration was 0.10 mm/year (0.021 to 0.481). The probability of not developing femoral cortical hypertrophy and proximal osteopenia by 12 years was 80.2% (95% confidence interval, 72.7 to 87.6) and 77.5% (95% confidence interval, 69.7 to 85.2), respectively. Despite these good clinical results, further follow-up is needed to determine whether these prostheses will loosen with time.

We conducted a longitudinal study including patients with the same type of primary hybrid total hip replacement and evaluated patient activity and femoral osteolysis at either five or ten years post-operatively. Activity was measured using the University of California, Los Angeles scale. The primary outcome was the radiological assessment of femoral osteolysis. Secondary outcomes were revision of the femoral component for aseptic loosening and the patients’ quality of life. Of 503 hip replacements in 433 patients with a mean age of 67.7 years (30 to 91), 241 (48%) were seen at five and 262 (52%) at ten years post-operatively. Osteolytic lesions were identified in nine of 166 total hip replacements (5.4%) in patients with low activity, 21 of 279 (7.5%) with moderate activity, and 14 of 58 (24.1%) patients with high activity. The risk of osteolysis increased with participation in a greater number of sporting activities. In multivariate logistic regression adjusting for age, gender, body mass index and the inclination angle of the acetabular component, the adjusted odds ratio for osteolysis comparing high vs moderate activity was 3.6 (95% confidence interval 1.6 to 8.3). Stratification for the cementing technique revealed that lower quality cementing increased the effect of high activity on osteolysis. Revision for aseptic loosening was most frequent with high activity. Patients with the highest activity had the best outcome and highest satisfaction.

In conclusion, of patients engaged in high activity, 24% had developed femoral osteolysis five to ten years post-operatively.

The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components.

A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis.

Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups.

Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation.

The introduction of a trabecular tantalum rod has been proposed for the management of early-stage osteonecrosis of the femoral head but serves as a single-point of support of the necrotic lesion. We describe a technique using two or three 4.2 mm (or later 4.7 mm) tantalum pegs for the prevention of collapse of the necrotic lesion. We prospectively studied 21 patients (26 hips) with non-traumatic osteonecrosis of the femoral head treated in this manner. Of these, 21 patients (24 hips) were available for radiological and clinical evaluation at a mean follow-up of 46 months (18 to 67). Radiological assessment showed that only eight hips deteriorated according to the Association Research Circulation Osseous classification, and four hips according to the Classification of the Japanese Investigation Committee of Health and Welfare. Functional improvement was obtained with an improvement in the mean Harris hip score from 65.2 (33.67 to 95) to 88.1 (51.72 to 100), the mean Merle D’Aubigné-Postel score from 13 (6 to 18) to 16 (11 to 18), a mean visual analogue score for pain from 5.2 (0 to 9.5) to 2.6 (0 to 7), and the mean Short-Form 36 score from 80.4 (56.8 to 107.1) to 92.4 (67.5 to 115.7). Of these 24 hips followed for a minimum of 18 months, three were considered as failures at the final follow-up, having required total hip replacement. One of the hips without full follow-up was also considered to be a failure. In more than two-thirds of the surviving hips a satisfactory clinical outcome was achieved with promising radiological findings. The estimated mean implant survival was 60 months (95% confidence interval 53.7 to 66.3).

We report a 12- to 15-year implant survival assessment of a prospective single-surgeon series of Birmingham Hip Resurfacings (BHRs). The earliest 1000 consecutive BHRs including 288 women (335 hips) and 598 men (665 hips) of all ages and diagnoses with no exclusions were prospectively followed-up with postal questionnaires, of whom the first 402 BHRs (350 patients) also had clinical and radiological review.

Mean follow-up was 13.7 years (12.3 to 15.3). In total, 59 patients (68 hips) died 0.7 to 12.6 years following surgery from unrelated causes. There were 38 revisions, 0.1 to 13.9 years (median 8.7) following operation, including 17 femoral failures (1.7%) and seven each of infections, soft-tissue reactions and other causes. With revision for any reason as the end-point Kaplan–Meier survival analysis showed 97.4% (95% confidence interval (CI) 96.9 to 97.9) and 95.8% (95% CI 95.1 to 96.5) survival at ten and 15 years, respectively. Radiological assessment showed 11 (3.5%) femoral and 13 (4.1%) acetabular radiolucencies which were not deemed failures and one radiological femoral failure (0.3%).

Our study shows that the performance of the BHR continues to be good at 12- to 15-year follow-up. Men have better implant survival (98.0%; 95% CI 97.4 to 98.6) at 15 years than women (91.5%; 95% CI 89.8 to 93.2), and women < 60 years (90.5%; 95% CI 88.3 to 92.7) fare worse than others. Hip dysplasia and osteonecrosis are risk factors for failure. Patients under 50 years with osteoarthritis fare best (99.4%; 95% CI 98.8 to 100 survival at 15 years), with no failures in men in this group.

Cite this article: Bone Joint J 2014;96-B:1298–1306.

Cementless femoral stems are currently preferred for total hip replacement (THR) in the United States. Improvements in stem design, instrumentation and surgical technique have made this technology highly successful, reproducible, and applicable to the vast majority of patients requiring a THR. However, there are ongoing developments in some aspects of stem design that influence clinical results, the incidence of complications and their inherent adaptability in accommodating the needs of individual patients. Here we examine some of these design features.

Cite this article: Bone Joint J 2013;95-B, Supple A:53–6.

The purpose of this study was to define immediate post-operative ‘quality’ in total hip replacements and to study prospectively the occurrence of failure based on these definitions of quality. The evaluation and assessment of failure were based on ten radiological and clinical criteria. The cumulative summation (CUSUM) test was used to study 200 procedures over a one-year period. Technical criteria defined failure in 17 cases (8.5%), those related to the femoral component in nine (4.5%), the acetabular component in 32 (16%) and those relating to discharge from hospital in five (2.5%). Overall, the procedure was considered to have failed in 57 of the 200 total hip replacements (28.5%). The use of a new design of acetabular component was associated with more failures. For the CUSUM test, the level of adequate performance was set at a rate of failure of 20% and the level of inadequate performance set at a failure rate of 40%; no alarm was raised by the test, indicating that there was no evidence of inadequate performance.

The use of a continuous monitoring statistical method is useful to ensure that the quality of total hip replacement is maintained, especially as newer implants are introduced.

This systematic review of the literature summarises the clinical experience with ceramic-on-ceramic hip bearings over the past 40 years and discusses the concerns that exist in relation to the bearing combination. Loosening, fracture, liner chipping on insertion, liner canting and dissociation, edge-loading and squeaking have all been reported, and the relationship between these issues and implant design and surgical technique is investigated. New design concepts are introduced and analysed with respect to previous clinical experience.

The orientation of the acetabular component can influence both the short- and long-term outcomes of total hip replacement (THR). We performed a prospective, randomised, controlled trial of two groups, comprising of 40 patients each, in order to compare freehand introduction of the component with introduction using the transverse acetabular ligament (TAL) as a reference for anteversion. Anteversion and inclination were measured on pelvic radiographs.

With respect to anteversion, in the freehand group 22.5% of the components were outside the safe zone versus 0% in the transverse acetabular ligament group (p = 0.002). The mean angle of anteversion in the freehand group was 21° (2° to 35°) which was significantly higher compared with 17° (2° to 25°) in the TAL group (p = 0.004). There was a significant difference comparing the variations of both groups (p = 0.008).

With respect to inclination, in the freehand group 37.5% of the components were outside the safe zone versus 20% in the TAL group (p = 0.14). There was no significant difference regarding the accuracy or variation of the angle of inclination when comparing the two groups.

The transverse acetabular ligament may be used to obtain the appropriate anteversion when introducing the acetabular component during THR, but not acetabular component inclination.

Cite this article: Bone Joint J 2014;96-B:312–18.

Surface hip replacement (SHR) is generally used in younger, active patients as an alternative conventional total hip replacement in part because of the ability to preserve femoral bone. This major benefit of surface replacement will only hold true if revision procedures of SHRs are found to provide good clinical results.

A retrospective review of SHR revisions between 2007 and 2012 was presented, and the type of revision and aetiologies were recorded. There were 55 SHR revisions, of which 27 were in women. At a mean follow-up of 2.3 years (0.72 to 6.4), the mean post-operative Harris hip score (HHS) was 94.8 (66 to 100). Overall 23 were revised for mechanical reasons, nine for impingement, 13 for metallosis, nine for unexplained pain and one for sepsis. Of the type of revision surgery performed, 14 were femoral-only revisions; four were acetabular-only revisions, and 37 were complete revisions.

We did not find that clinical scores were significantly different between gender or different types of revisions. However, the mean post-operative HHS was significantly lower in patients revised for unexplained pain compared with patients revised for mechanical reasons (86.9 (66 to 100) versus 99 (96 to 100); p = 0.029). There were two re-revisions for infection in the entire cohort.

Based on the overall clinical results, we believe that revision of SHR can have good or excellent results and warrants a continued use of the procedure in selected patients. Close monitoring of these patients facilitates early intervention, as we believe that tissue damage may be related to the duration of an ongoing problem. There should be a low threshold to revise a surface replacement if there is component malposition, rising metal ion levels, or evidence of soft-tissue abnormalities.

Cite this article: Bone Joint J 2013;95-B, Supple A:88–91.

Hip replacement is a very successful operation and the outcome is usually excellent. There are recognised complications that seem increasingly to give rise to litigation. This paper briefly examines some common scenarios where litigation may be pursued against hip surgeons. With appropriate record keeping, consenting and surgical care, the claim can be successfully defended if not avoided. We hope this short summary will help to highlight some common pitfalls. There is extensive literature available for detailed study.

In 2012 we reviewed a consecutive series of 92 uncemented THRs performed between 1986 and 1991 at our institution using the CLS Spotorno stem, in order to assess clinical outcome and radiographic data at a minimum of 21 years. The series comprised 92 patients with a mean age at surgery of 59.6 years (39 to 77) (M:F 43;49).

At the time of this review, seven (7.6%) patients had died and two (2.2%) were lost to follow-up. The 23-year Kaplan–Meier survival rates were 91.5% (95% confidence intervals (CI) 85.4% to 97.6%; 55 hips at risk) and 80.3% (95% CI, 71.8% to 88.7%; 48 hips at risk) respectively, with revision of the femoral stem or of any component as endpoints. At the time of this review, 76 patients without stem revision were assessed clinically and radiologically (mean follow-up 24.0 years (21.5 to 26.5)). For the 76 unrevised hips the mean Harris hip score was 87.1 (65 to 97). Femoral osteolysis was detected in five hips (6.6%) only in Gruen zone 7. Undersized stems were at higher risk of revision owing to aseptic loosening (p = 0.0003). Patients implanted with the stem in a varus position were at higher risk of femoral cortical hypertrophy and thigh pain (p = 0.0006 and p = 0.0007, respectively).

In our study, survival, clinical outcome and radiographic data remained excellent in the third decade after implantation. Nonetheless, undersized stems were at higher risk of revision owing to aseptic loosening.

Cite this article: Bone Joint J 2014;96-B:455–61.

In a prospective study, 93 unselected consecutive uncemented hip arthroplasties were performed in 80 patients using the titanium-coated RM acetabular component and the CLS femoral component. The mean age of the patients at operation was 52 years (28 to 81). None were lost to follow-up. In the 23 patients who had died (26 hips) only one acetabular component had been revised. In the 57 living patients (67 hips), 13 such revisions had been performed. Of the 14 revisions, seven were for osteolysis, five for loosening and two for infection.

Survival analysis of this implant showed a total probability of survival of 83% (95% confidence interval 73 to 90), with all revisions as the endpoint, and a probability of 94% (95% confidence interval 87 to 98) with revision for aseptic loosening as the endpoint, indicating reliable long-term fixation of the titanium-coated RM acetabular component.

The increasing need for total hip replacement (THR) in an ageing population will inevitably generate a larger number of revision procedures. The difficulties encountered in dealing with the bone deficient acetabulum are amongst the greatest challenges in hip surgery. The failed acetabular component requires reconstruction to restore the hip centre and improve joint biomechanics. Impaction bone grafting is successful in achieving acetabular reconstruction using both cemented and cementless techniques. Bone graft incorporation restores bone stock whilst providing good component stability. We provide a summary of the evidence and current literature regarding impaction bone grafting using both cemented and cementless techniques in revision THR.

Cite this article: Bone Joint J 2013;95-B, Supple A:98–102.

The conventional method for reconstructing acetabular bone loss at revision surgery includes using structural bone allograft. The disadvantages of this technique promoted the advent of metallic but biocompatible porous implants to fill bone defects enhancing initial and long-term stability of the acetabular component. This paper presents the indications, surgical technique and the outcome of using porous metal acetabular augments for reconstructing acetabular defects.

Cite this article: Bone Joint J 2013;95-B, Supple A:103–8.

We performed a case–control study to compare the rates of further surgery, revision and complications, operating time and survival in patients who were treated with either an uncemented hydroxyapatite-coated Corail bipolar femoral stem or a cemented Exeter stem for a displaced intracapsular fracture of the hip. The mean age of the patients in the uncemented group was 82.5 years (53 to 97) and in the cemented group was 82.7 years (51 to 99) We used propensity score matching, adjusting for age, gender and the presence or absence of dementia and comorbidities, to produce a matched cohort receiving an Exeter stem (n = 69) with which to compare the outcome of patients receiving a Corail stem (n = 69). The Corail had a significantly lower all-cause rate of further surgery (p = 0.016; odds ratio (OR) 0.18, 95% CI 0.04 to 0.84) and number of hips undergoing major further surgery (p = 0.029; OR 0.13, 95% CI 0.01 to 1.09). The mean operating time was significantly less for the Corail group than for the cemented Exeter group (59 min [12 to 136] vs 70 min [40 to 175], p = 0.001). The Corail group also had a lower risk of a peri-prosthetic fracture (p = 0.042; OR 0.19, 95% CI 0.01 to 1.42) . There was no difference in the mortality rate between the groups. There were significantly fewer complications in the uncemented group, suggesting that the use of this stem would result in a decreased rate of morbidity in these frail patients. Whether this relates to an improved functional outcome remains unknown.

Cite this article: Bone Joint J 2014;96-B:299–305.

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively.

A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen.

In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern.

Cite this article: Bone Joint J 2014; 96-B:868–75.

In a prospective randomised clinical study acetabular components were implanted either freehand (n = 30) or using CT-based (n = 30) or imageless navigation (n = 30). The position of the component was determined post-operatively on CT scans of the pelvis.

Following conventional freehand placement of the acetabular component, only 14 of the 30 were within the safe zone as defined by Lewinnek et al (40° inclination sd 10°; 15° anteversion sd 10°). After computer-assisted navigation 25 of 30 acetabular components (CT-based) and 28 of 30 components (imageless) were positioned within this limit (overall p < 0.001). No significant differences were observed between CT-based and imageless navigation (p = 0.23); both showed a significant reduction in variation of the position of the acetabular component compared with conventional freehand arthroplasty (p < 0.001). The duration of the operation was increased by eight minutes with imageless and by 17 minutes with CT-based navigation.

Imageless navigation proved as reliable as that using CT in positioning the acetabular component.

We report a multicentre prospective consecutive study assessing the long-term outcome of the proximally hydroxyapatite (HA)-coated ABG II monobloc femoral component in a series of 1148 hips in 1053 patients with a mean age at surgery of 64.77 years (22 to 80) at a mean follow-up of 10.84 years (10 to 15.25). At latest follow-up, the mean total Harris hip score was 94.7 points (sd; 6.87; 49 to 100), and the mean Merle d’Aubigné–Postel score was 17.6 points (sd 1.12; 7 to 18). The mean total Engh radiological score score was 21.54 (sd 5.77; 3.5 to 27), with 95.81% of ‘confirmed ingrowth’, according to Engh’s classification. With aseptic loosening or pain as endpoints, three AGB II stems (0.26%) failed, giving a 99.7% survival rate (se 0.002; 95% confidence interval (CI) 0.994 to 1) at 14 years’ follow-up. The survival of patients ≤ 50 years of age (99.0% (se 0.011; 95% CI 0.969 to 1)) did not differ significantly from those of patients aged > 50 years (99.8% (se 0.002; 95% CI 0.994 to 1)). This study confirmed the excellent long-term results currently achieved with the ABG II proximally HA-coated monobloc stem.

Cite this article: Bone Joint J 2013;95-B:1610–16.

Revision surgery of the hip was performed on 114 hips using an extensively porous-coated femoral component. Of these, 95 hips (94 patients) had a mean follow-up of 10.2 years (5 to 17). No cortical struts were used and the cortical index and the femoral cortical width were measured at different levels.

There were two revisions for aseptic loosening. Survivorship at 12 years for all causes of failure was 96.9% (95% confidence interval 93.5 to 100) in the best-case scenario. Fibrous or unstable fixation was associated with major bone defects. The cortical index (p = 0.045) and the lateral cortical thickness (p = 0.008) decreased at the proximal level over time while the medial cortex increased (p = 0.001) at the proximal and distal levels. An increase in the proximal medial cortex was found in patients with an extended transtrochanteric osteotomy (p = 0.026) and in those with components shorter than 25 cm (p = 0.008).

The use of the extensively porous-coated femoral component can provide a solution for difficult cases in revision surgery. Radiological bony ingrowth is common. Although without clinical relevance at the end of follow-up, the thickness of the medial femoral cortex often increased while that of the lateral cortex decreased. In cases in which a shorter component was used and in those undertaken using an extended trochanteric osteotomy, there was a greater increase in thickness of the femoral cortex over time.

Peri-prosthetic bone loss caused by stress shielding may be associated with aseptic loosening of femoral components. In order to increase primary stability and to reduce stress shielding, a three-dimensional, cementless individual femoral (Evolution K) component was manufactured using pre-operative CT scans. Using dual energy x-ray absorptiometry, peri-prosthetic bone density was measured in 43 patients, three months, six months, 3.6 and 4.6 years after surgery. At final follow-up there was a significant reduction in mean bone density in the proximal Gruen zones of −30.3% (zone 7) and −22.8% (zone 1). The density in the other zones declined by a mean of between −4% and −16%. We conclude that the manufacture of a three-dimensional, custom-made femoral component could not prevent a reduction in peri-prosthetic bone density.

We performed 114 consecutive primary total hip arthroplasties with a cementless expansion acetabular component in 101 patients for advanced osteonecrosis of the femoral head. The mean age of the patients at surgery was 51 years (36 to 62) and the mean length of follow-up was 110 months (84 to 129).

The mean pre-operative Harris hip score of 47 points improved to 93 points at final follow-up. The polyethylene liner was exchanged in two hips during this period and one broken acetabular component was revised. The mean linear wear rate of polyethylene was 0.07 mm/year and peri-acetabular osteolysis was seen in two hips (1.9%). Kaplan-Meier analysis indicated that the survival of the acetabular component without revision was 97.8% (95% confidence interval 0.956 to 1.000) at ten years.

Our study has shown that the results of THA with a cementless expansion acetabular component and an alumina-polyethylene bearing surface are good.

Revision total hip arthroplasty (THA) is projected to increase by 137% from the years 2005 to 2030. Reconstruction of the femur with massive bone loss can be a formidable undertaking. The goals of revision surgery are to create a stable construct, preserve bone and soft tissues, augment deficient host bone, improve function, provide a foundation for future surgery, and create a biomechanically restored hip. Options for treatment of the compromised femur include: resection arthroplasty, allograft prosthetic composite (APC), proximal femoral replacement, cementless fixation with a modular tapered fluted stem, and impaction grafting. The purpose of this article is to review the treatment options along with their associated outcomes in the more severe femoral defects (Paprosky types IIIb and IV) in revision THA.