The radiographic analysis of over 5000 metal on metal (MoM) hips using Ein Bild Roentgen Analyse (EBRA) software have been recently published in an attempt to determine the influence of cup orientation on bearing function. The validation of this software relies one study, conducted in a phantom pelvis without a femoral head in situ. Three dimensional computed tomographic (3D-CT) has been shown to be more accurate for hip and knee arthroplasty than plain radiographs for measurements of component orientation and position. The accuracy of EBRA when compared to 3D-CT for MoM hips specifically is unclear. We measured the cup orientation of 96 large diameter MoM hips using EBRA analysis of plain radiographs and compared this to 3D-CT. All measurements were made using the radiographic definition of cup orientation. The mean difference in version between the two imaging modalities was 8°; with wide limits of agreement of −21.2° and +5.6°. Three retroverted cups were not detected by EBRA. The mean difference in inclination values was 0.3°, but there was up to 9°difference between imaging modalities. When measured by 3D CT, 64% of hips were within a 10° safe zone around 45° inclination and 20° version, compared to only 24% when measured by EBRA (Fishers Exact test, p< 0.0001). The measurement of cup orientation of MoM hips using EBRA software is insufficiently accurate, particularly for the assessment of cup version. The cup rim is obscured by the large diameter femoral head on plain radiographs. Research studies using EBRA analysis for version have limited value if accuracy of more than 20 degrees is required to draw conclusions. This software may not be suitable to measure the performance of a device or surgeon. The limitations of EBRA can be overcome, if 3D-CT with an extended Hounsfield scale for data capture is used

We aimed to determine whether the EBRA method had greater precision and sensitivity for measuring implant migration following total hip arthroplasty (THA) than direct plain radiographic techniques using modern measuring tools. Short-term precision was evaluated in 20 subjects following THA. Consecutive, standardised radiographs of the hip were performed on the same day after repositioning. Prosthetic cup and stem migration were measured from the plain radiographs using a digital calliper following methods described by Ianotti, Malchau, Nunn, Sutherland and Wetherall, and compared to those made using EBRA. Precision was expressed as 95% confidence interval (95%CI = 1.96x Std.dev.). 10 subjects were then followed prospectively with standardised plain radiographs at baseline, 6,12 and 26 weeks after THA. Migration measurements made using EBRA were compared to those made using the most precise plain radiographic method. The 95%CI of all EBRA cup and stem measurements was ±1mm or smaller. Only the Sutherland method had a similar level of precision (95%CI ±1.11 to 1.28 mm: F-Test P> 0.05; all other method comparisons with EBRA P< 0.05). In the longitudinal study cup cranial migration of 0.53 mm (SEM 0.19) and stem subsidence of 1.53 mm (SEM 0.19) were detected using EBRA (2-way ANOVA by rank; P< 0.05 and P< 0.001 respectively). No statistically significant migration of the cup or stem was detected using the Sutherland method. The EBRA method is a precise method for describing implant migration in small groups of patients in the early period following THA, and manual methods lack sufficient precision to be used for this purpose

Background: Resurfacing cups may produce significant clinical problems when placed at the extremes of version, including increased production of metal debris and psoas tendonitis. Methods: We obtained the femoral and acetabular components of two unused ASR (Articular Surface Replacement) and BHR (Birmingham Hip Resurfacing) devices. The components were placed in moulds at varying degrees of inclination and anteversion in a grid to simulate pelvic landmarks and AP radiographic images were captured. The true radiological anteversion was determined by rotating the x-ray beam so that it was perpendicular to the acetabular axis and measuring the angle subtended by the cup rim and the vertical axis. Five blinded orthopaedic registrars then used EBRA (Einzel-Bild-Roentgen-Analysis, University of Inns-bruck, Austria) software to determine the radiological anteversion from the AP films. Twenty-five ASR and twenty-five BHR images were analysed. At the same time each observer was asked to grade the cups as “1” (< 10°) “2” (10–20°) “3” (20–30°) or “4” (> 30°) depending on the appearances of the cup vertices. Results: Mean error for each observer was −0.7 (minimum) to 1.6° (maximum). The range of standard deviations of error for each observer was +/− 2.2 (minimum) to 3.5° (maximum). Retroverted cups were not identified in the majority of cases. Cups graded as “1” or “4” showed high sensitivity and specificity for the true grade as determined on the lateral radiographs. Conclusions: EBRA software can be used to calculate the anteversion of resurfacing cups to a clinically acceptable degree. The clinician must be aware of the limitations of the software most notably the difficulty in identifying a retroverted cup and errors arising from poor quality radiographs in terms of pelvic rotation. The presented clinical grading system can be used as a rapid assessment tool to identify cups at the extremes of anteversion

This study aimed to compare the early clinical results and stem subsidence between three consecutive series of revision hip replacement cases with femoral impaction bone grafting to evaluate the effects of developments in technique. In the original series 1 (n=23), bone graft was irradiated at 25kG. I n series 2 (n=12) non-irradiated double washed graft and long stems were used as required. In series 3 (n=21) modular tamps were used. Sensitive radiographic analysis techniques, EBRA and RSA, were used to measure stem subsidence. Major stem re-revision was required in five hips in series one, one hip in series two and no hips in series three. Two periprosthetic fractures occurred in series one. There was a statistically significant reduction in stem subsidence at the cement-bone interface at 12 months between series one and series two and three (p<0.05). In series three there was negligible stem subsidence at the cement-bone interface. Technique developments in femoral impaction grafting, including the use of modular tamps designed to simply the procedure, yields excellent early clinical and radiographic results. Using RSA, we have shown that the fixation of the stems in bone is comparable to that achieved in primary hip replacement

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.

Femoral head diameters in THA have been increasing due to good long-term outcomes of 1^st generation HXLP cups. Furthermore, some 2^nd generation HXLP cups allow 36mm or larger heads. However, larger femoral head diameters increase the frictional torque and may lead to early cup migration and loosening. And there is a concern that larger head diameters and reduced liner thickness may increase polyethylene wear. In this study, we compared early acetabular component migration and wear rates between a group of larger heads using a 2^nd generation HXLP and a group smaller heads using a 1^st generation HXLP.

The larger head group comprising 30 hips underwent THA between February 2010 and March 2011 with the use of a sequentially cross-linked polyethylene liner (X3). 30 patients were included in this study (30 women). Their mean age was 59.3years; mean weight was 53.6kg. Trident HA-coated cementless cups were used and the sizes ranged from 46mm to 56mm (mean 50.5mm). The head diameters were 36mm in 23hips, 40mm in 5 hips, and 44mm in 2hips. All X3 liners were 5.9mm or less in thickness.

A control group was selected from a previous case series that had undergo THA between July 2007 and January 2008 using a 1st generation HXLP liner (Crossfire) by matching age and sex. Therefore 30 patients were included in this study (30 women) too. Their mean age was 60.0 years; mean weight was 55.5kg. The same Trident cups were used and the sizes ranged from 46mm to 56mm (mean 49.5mm). The head diameters were 26mm in 19hips and 32mm in 11hips. The liner thicknesses were 7.8mm or more.

All hips had standardized anteroposterior pelvic digital radiographs performed postoperatively and cup migration was measured on digital radiographs at the immediate postoperative period and two year using EBRA-CUP software. We analyzed horizontal and vertical cup migration distance and the difference in cup anteversion and inclination angle at two years. Additionally, total head penetrarion and polyethylene liner volumetric wear rates were measured using a computer-assited method with PolyWear software.

The larger head group revealed an average of 0.48mm of horizontal migration, 0.75mm of vertical migration, 0.19degree of inclination change, and 1.26 degrees of anteversion change. The control group showed an average of 0.63mm of horizontal migration, 0.36mm of vertical migration, 0.07 degree of inclination change, and 0.88 degree of anteversion change. Based on the EBRA-CUP measurements, there were no cases of significant early loosening which was indicated by more than 1mm of migration, more than 2.5 degree of inclination change, or more than 3.3 degree of anteversion change.

The liner penetration rates were 0.388±0.192mm/yr in the large head group and 0.362±0.178mm/yr in the control group. The difference was not significant (p=0.64.) The volumetric wear rates were 42.8±27.9mm⁁3/yr in the large head group and 42.0±33.0mm⁁3/yr in the control group. Again, the difference was not significant (p=0.94).

No significant early cup migration or increased wear rate were detected in THA with the sequentially cross-linked polyethylene liner and 36mm or large heads at two years.

Objectives. High failure rates of metal-on-metal hip arthroplasty implants have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices. The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage. We aimed to identify validated surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty (THA). Methods. We conducted a systematic review of studies evaluating surrogate markers for predicting long-term outcome in primary THA. Long-term outcome was defined as revision rate of an implant at ten years according to National Institute of Health and Care Excellence guidelines. We conducted a search of Medline and Embase (OVID) databases. Separate search strategies were devised for the Cochrane database and Google Scholar. Each search was performed to include articles from the date of their inception to June 8, 2015. Results. Our search strategy identified 1082 studies of which 115 studies were included for full article review. Following review, 17 articles were found that investigated surrogate markers of long-term outcome. These included one systematic review, one randomised control trial (RCT), one case control study and 13 case series. Validated surrogate markers included Radiostereometric Analysis (RSA) and Einzel-Bild-Röntgen-Analyse (EBRA), each measuring implant migration and wear. We identified five RSA studies (one systematic review and four case series) and four EBRA studies (one RCT and three case series). Patient Reported Outcome Measures (PROMs) at six months have been investigated but have not been validated against long-term outcomes. Conclusions. This systematic review identified two validated surrogate markers of long-term primary THA outcome: RSA and EBRA, each measuring implant migration and wear. We recommend the consideration of RSA in the pre-market testing of new implants. EBRA can be used to investigate acetabular wear but not femoral migration. Further studies are needed to validate the use of PROMs for post-market surveillance. Cite this article: T. T. Malak, J. A. J. Broomfield, A. J. R. Palmer, S. Hopewell, A. Carr, C. Brown, D. Prieto-Alhambra, S. Glyn-Jones. Surrogate markers of long-term outcome in primary total hip arthroplasty: A systematic review. Bone Joint Res 2016;5:206–214. DOI: 10.1302/2046-3758.56.2000568

Porous tantalum is a highly osteoinductive biomaterial, initially introduced in orthopedics in 1997, with a subsequent rapid evolution of orthopedic applications. The use of porous tantalum for the acetabular component in primary total hip arthroplasty (THA) has demonstrated excellent short-term and mid-term results. However, long term data are scarce. The purpose of this prospective study is to report the long-term clinical and radiological outcome following use of an uncemented porous tantalum acetabular component in primary THA with a minimum follow-up of 17.5 years, in a previously studied cohort of patients. We prospectively followed 128 consecutive primary THAs in 140 patients, between November 1997 and June 1999. A press-fit porous tantalum monoblock acetabular component was used in all cases. The presence of initial gaps in the polar region, as sign of incomplete seating of the monoblock cup, was assessed on the immediate postoperative radiographs. All patients were followed clinically and radiographically at 6, 12, and 24 weeks and 12 months and then at 2, 5, 8, 10, and 19 years, for a mean of 18.1 years (range 17.5 – 19 years). Periacetabular dome gap filling, acetabular cup migration and polyethylene wear were assessed by the EBRA digital measurement system, until 2 years postoperatively. Mean age of patients at the time of operation was 60.4 years old (range 24 – 72). Harris hip score, Oxford Hip Score and range of motion (ROM) were dramatically improved in all cases (p < 0.001). In the initial postoperative radiographs, periacetabular dome gaps were observed in the 15% of cases, and were progressively filled within 6 months. In 2 years postoperatively, the mean component migration, as shown in EBRA study, was 0.67 mm. At last follow-up, all cups were radiographically stable with no evidence of migration, gross polyethylene wear, progressive radiolucencies, osteolytic lesions or acetabular fractures. The survivorship with re-operation for any reason as end point was 92.8%, whereas the survivorship for aseptic loosening as an end point was 100%. Upon visual inspection, two removed acetabular components due to recurrent dislocation and infection, respectively, showed extensive bone osseointegration. In our primary THA series, the porous tantalum monoblock cup demonstrated excellent clinical and radiographic outcomes with no failures because of aseptic loosening at a mean follow-up of 18.1 years. Porous tantalum acetabular components showed excellent initial stability, produced less wear debris and revealed a great potential for bone ingrowth. Due to its unique osteoinductive properties and elliptical shape, porous tantalum monoblock cups have demonstrated superior short and long-term survivorship compared to other press fit prostheses in the market

Background. Migration analysis after total joint arthroplasty are performed using EBRA analysis (Krismer et al., 1997) or - more accurate but also much more cost-intensive and time-consuming – via radiostereometric analysis (RSA). For the latter, additional radiographs from two inclined perspectives are needed in regular intervals in order to define the position of the implant relative to tantalum bone markers which have been implanted during surgery of the artificial joint (Fig. 1). Modern analysis software promises a migration precision along the stem axis of a hip implant of less than 100 μm (Witvoet-Brahm et al., 2007). However, as the analysis is performed semi-automatically, the results are still dependent on the subjective evaluation of the X-rays by the observer. Thus, the present phantom study aims at evaluating the inter- and intra-observer reliability, the repeatability as well as the precision and gives insight into the potential and limits of the RSA method. Materials and Methods. Considering published models, an RSA phantom model has been developed which allows a continuous and exact positioning of the prostheses in all six degrees of freedom (Fig. 2). The position sensitivities of the translative and rotative positioning components are 1 μm and 5 to 24, respectively. The roentgen setup and Model-Based RSA software (3.3, Medis specials bv, Leiden, Netherlands) was evaluated using the SL-PLUS® standard hip stem (size 7, Smith & Nephew, Baar, Switzerland). The inter-observer (10 repetitions) and intra-observer (3 observers) reliability have been considered. Additionally, the influences of the model repositioning and inclination as well as the precision after migration and rotation along the stem axis are investigated. Results and Discussion. Precision along the stem axis was determined to 161 μm (± 230 μm), in the lateral plane 100 μm (± 85 μm) and maximal rotations to 0.524° (± 1.268°). High reproducibility (intra-observer reliability) is reported with relevant influences of the inclination of the implant on the radiograph, in particular for the first clinical scene which serves as a reference. Deviations after translations along the stem axis are 0.37 ± 1.92% and −3.28 ± 6.62% after rotations. In conclusion, the precision given by the software producer of less than 100 μm could not be verified. Beside the limitations from the software, potential sources of errors are the subjective analysis by the observer, a small number of bone markers and the positioning of the implant (patient) during X-ray examination. Though, Model-Based RSA largely outmatches the EBRA approach in terms of measuring implant migration. However, standardization of the X-rays and RSA analysis is recommended

Introduction: The Allofit cup is a hemispherical pressfit cup with a flattened pole for cementless implantation. Clinical use started in 1993 and we report our clinical and radiographic results of the first 100 cases. 75 hips of this group have been followed during the first 3 to 4 years using EBRA for migration analysis. These results also are presented. Material: Out of 100 hips 81 have been followed mith a mean of 10,1 years (9,8–11). 6 patients died, 11 did not show for follow up an 1 patient had a revision for deep infection with two-stage exchange meanwhile. The initial diagnosis was primary coxarthrosis in 63, rheumatoid arthritis in 10, congenital dislocation of the hip in 5 and necrosis of the femoral hed in 3. In all cases the cementless Alloclassic stem was used, as bearing material metasul was implanted in 73 and ceramic-polyethylene in 8 cases. Complications: For prolonged exsudation from the wound one soft tissue revision was necessary. 2 luxations were treated conservative. One early deep infection healed after synovectomy and irrigation, one late deep infection was cured by a two stage reimplantation. Results: The EBRA migration analysis after 3,6 years (2,3–4,2) showed cranial migration of 0,35 mm (0,2–0,6 mm), medial migration of 0,25 mm (0,10–0,40 mm) and a calculated total migration as a combination of both of 0,45 mm (0,22–0,72). Therefore at this time there was no evidence of early loosening or migration indicating later loosening. The preoperative Harris hip score was 53,13 pts (23–73), the postoperative score after 10 years 96,5 (78–100). Radiographic evaluation after 10 years showed no lucencies in 78 of 81 jpints. 3 hips had a lucent line of 1mm in zone III. We detected no signs of osteolysis, loosening or migration. No reoperations for any reason exept 2 septic cases have been performed yet. Summary: After 10 years the clinical and radiological results of this implant are very satisfying. These results confirm the early observations of a migration analysis performed 6 to 8 years before

Introduction. Acetabular component positioning, offset, combined anteversion, leg length, and soft tissue envelope around the hip plays an important role in hip function and durability. In this paper we will focus on acetabular positioning of the cup. Technique. The axis of the pelvis is identified intra-operatively as a line drawn from the highest point of the iliac crest to the middle of the greater trochanter. Prior to reaming the acetabulum, an undersized trial acetabular component is placed parallel and inside the transverse ligament, inside the anterior column and projecting posterior to the axis of the pelvis. This direction is marked and the subsequent reaming and final component placement is performed in the same direction. The lateral opening is judged based on the 45-degree angle from the tear drop to the lateral margin of the acetabulum on anteroposterior pelvic radiographs. The final anteversion of the cup is adjusted based on increased or decreased lumbar lordosis and combined anteversion. Methods. Anteroposterior pelvic radiographs of 100 consecutive patients undergoing posterior THR between September 2010 and March 2011 with this method were evaluated for cup inclination angle and anteversion using EBRA software. Results. There were no malalignments or dislocations. The mean cup inclination angle and anteversion were 41 ± 5.1 degrees (range 37.1 – 48.4) and 22.1 ± 4.8 degrees (range 16.6 – 29.3), respectively. Conclusion. This is a reproducible method of cup positioning and with proper femoral component position and restoring leg length, offset, combined anteversion, and balance soft tissue around the hip. These factors affect the incidence of dislocation, infection, reduced wear, and durability

The Exeter (Howmedica Ltd) and Ultima-TPS (Depuy Ltd) implants are both collarless, polished, double-tapered, cemented femoral implants. The Exeter is manufactured in stainless steel and has an excellent long-term survivorship. The Ultima-TPS is manufactured in cobalt-chrome and has been recently introduced. The aim of this study was to compare the early performance of these implants in a 2-year randomised clinical trial. 65 patients with unilateral hip osteoarthritis were randomised to receive either the Exeter or TPS stem. All received a Charnley Cup. Outcome measures included the Oxford Hip Questionnaire, proximal femoral bone mineral density (BMD) measured by dual energy x-ray absorptiometry, and implant subsidence measured using EBRA. At 2 years 43 patients (66%) were reviewed. 22 patients (mean age 70 years, 16 female, BMI 27.9Kg/m. 2. ) received the TPS implant, and 21 patients (mean age 70 years, 15 female, BMI 28.9Kg/m. 2. ) received the Exeter implant. 19 patients withdrew for reasons unrelated to the study, 2 died, and 1 was withdrawn after deep wound infection. Complete Oxford hip scores were available pre-operatively and at 2 years in 37 patients (n=20 TPS). Median (IQR) pre-operative hip scores were 51 (43 to 54) and 48 (36 to 53) for the TPS and Exeter implants, respectively. At 2 years the hip scores improved to 24 (18 to 31) and 22 (16 to 31), respectively. There were no differences in scores between groups at each time-point. There were no differences in BMD between groups at pre-operative baseline, 3 months, 1 and 2 years (Gruen zones 1–7, all time-points; n=19 TPS, n=13 Exeter implants: P> 0.05). Maximum bone loss was seen in Gruen zone 7 at 2 years for bone implants (TPS-11%, Exeter -14%, P> 0.05). Measurement of subsidence over 2 years using EBRA was possible in 20 patients (n=7 TPS, n=13 Exeter). Mean subsidence at 2 years was 1.62mm for the TPS implant and 1.60mm for the Exeter implant (P> 0.05). There was no plain radiographic evidence of osteolysis in either group. These data suggest that the early performance of the two implants studied is similar. However, long-term survivorship data is required to confirm their equivalency

We aimed to investigate the clinical consequences of intraoperative acetabular fractures. Between 2003 and 2012, a total of 3391 cementless total hip arthroplasties (THA) were performed at the Dept. of Orthopaedics, Innsbruck Medical University. Of those, a total of 160 patients underwent a CT scan within 30 days postoperatively. The scans of 44 patients were not suitable for analyse due to thick scan layers. Of the remaining 116 patients, 76 had a fracture. Reasons for CT-scans were suspected bleeding, hip pain, abdominal symptoms, etc. The fractures included 59 isolated acetabular fractures, the rest of fractures was in the superior or inferior pubic ramus or the tuber ischiadicum. Four cases out of the 59 acetabular fractures underwent revision surgery due to periprosthetic joint infection after 0, 2, 10 and 23 months. Four patients underwent revision due to cup loosening after 13 and 14 days as well as after 16 and 24 months. Of those, three showed a central acetabular fracture with protrusion. In 33 of the remaining 51 patients, a minimum of 3 x-rays was available for migration analysis with EBRA. In 6 patients, the x-rays were not comparable to each other. The 27 remaining acetabular fractures were categorised according to AO classification in 62A1 (1; posterior wall), 62A2 (16; posterior column), 62A3 (6; anterior wall), and others (4). Four hips showed initial migration of more than 3 mm in the first 6 months. One had a central fracture, and was lost for follow-up after 8 months. Two had an anterior column fracture and showed no further migration after 6 months. One showed also a radiolucency of more than 2 mm in all 3 zones and was lost for follow-up. We conclude that intraoperative acetabular fractures occur more often than we expected. Fractures of the acetabular ring involving one column do not seem to compromise the long-term stability of the implant. Central fractures required revision or showed loosening proved by high cup migration

Introduction: Acetabular component positioning, offset, combined anteversion, leg length, and soft tissue envelope around the hip plays an important role in hip function and durability. In this paper we will focus on acetabular positioning of the cup. Technique: The axis of the pelvis is identified intra-operatively as a line drawn from the highest point of the iliac crest to the middle of the greater trochanter. Prior to reaming the acetabulum, an undersized trial acetabular component is placed parallel and inside the transverse ligament, inside the anterior column and projecting posterior to the axis of the pelvis. This direction is marked and the subsequent reaming and final component placement is performed in the same direction. The lateral opening is judged based on 45-degree angle from the tear drop to the lateral margin of the acetabulum on anteroposterior pelvic radiographs. The final anteversion of the cup is adjusted based on increase or decrease of lumbar lordosis and combined anteversion. Methods: Anteroposterior pelvic radiographs of 100 consecutive patients undergoing posterior THR between September 2010 and March 2011 with this method were evaluated for cup inclination angle and anteversion using EBRA software. Results: There were no malalignment or dislocation. The mean cup inclination angle and anteversion were 41 ± 5.1 degrees (range 37.1 – 48.4) and 22.1 ± 4.8 degrees (range 16.6 – 29.3), respectively. Conclusion: This is a reproducible method of cup positioning and with proper femoral component position, restores leg length, offset, combined anteversion, and balances soft tissue around the hip. These factors affect the incidence of dislocation, infection, reduced wear, and durability

Introduction. Radiological Inclination (RI) is defined as the angle formed between the acetabular axis and the longitudinal axis when projected onto the coronal plane. Higher RI angles are associated with adverse outcomes. Methods. Primary aim: to investigate the effect of adjusting patient pelvic position in the transverse plane by using a ‘head-down’ (HD) operating table position. This was to determine, when aiming for 35° Apparent Operative Inclination (AOI), which operating table position most accurately achieved a target post-operative RI of 42°. N=270. Patients were randomised to one of three possible operating table positions:. 0°HD (Horizontal),. 7°HD, or. Y°HD (Patient Specific Table Position). Operating table position was controlled using a digital inclinometer. RI was measured using EBRA software. Results. 0° HD:Range 32.9–61.7°,Mean 47.1°,Mean deviation from target 5.8°. 7° HD:Range 24.0–53.8°,Mean 41.0°,Mean deviation from target 4.2°. Y° HD:Range 30.6–54.8°,Mean 43.3°,Mean deviation from target 3.9°. ANOVA: Significant differences in mean deviation from target RI between both the 0°HD/7°HD table positions (p=0.002) and the 0°HD/Y°HD table positions (p<0.001). Though the mean deviation from target RI was lower for the patient specific HD table position (3.9°) compared to the 7° HD table position (4.2°),this did not obtain significance (p=0.562). Discussion. When aiming for 42° RI, both the 7°HD table position and Patient Specific HD table position provided a narrower RI range, more desirable mean RI and statistically improved mean deviation from target RI when compared to the 0°HD table position. Conclusion. When aiming for 35° AOI in order to obtain a target RI of 42°, the surgeon should avoid pelvic adduction by considering a ‘head down’ operating table tilt

Introduction. Cup positioning in total hip arthroplasty (THA) is an important variable for short and long term durability of any hip implant. This novel method utilises internal and external bony landmarks, and the transverse acetabular ligament for positioning the acetabular component. Methods. The cup is placed parallel and superior to the transverse ligament and inside the anterior wall notch of the true acetabulum, and then adjusted for femoral version and pelvic tilt, fixed obliquity, and transverse rotational deformity based on weight bearing pre-operative radiographs. Seventy consecutive THRs (68 patients) were performed using the above technique. The cup radiographic and functional anteversion and abduction angle were measured on post-operative weight bearing pelvic radiographs using EBRA software. Results. The mean follow-up was 8.1 ± 2.4 months (4.3 – 11.8 months). There were no dislocations. The mean anteversion and abduction angle was 41.8 degrees ± 4.6 degrees and 18.5 degrees ± 4.4 degrees, respectively. In 3 hips, the radiographic abduction angle was slightly outside the safe zone of Lewinnek as measured based on the inter-teardrop line. However, when using a weight bearing AP pelvis radiograph to measure functional abduction angle using a horizontal line as a reference, they were all within the normal range. Discussion and Conclusion. The proposed technique utilises intra- and extra-articular bony landmarks, allows for adjustment for lumbosacral angle, abnormal femoral anteversion, and excessive acetabular version. The proposed technique is a reproducible and accurate method for cup placement with posterior exposure

Introduction. Total hip arthroplasty (THR) with non-cemented or hybrid fixation remains one of the most successful procedures performed today. The aim of this study was to assess the safety and efficacy of a hydroxyapatite (HA) coated, hemispherical cup. Material and Methods. Between 2003 and 2007, 223 THAs (210 patients) with peripheral self-locking (PSL) cup and highly cross-linked polyethylene (Crossfire, Stryker, Mahwah, NJ) with minimum 5 years clinical and radiographic follow-up (5–9 years) were analyzed. The mean age was 62.5 years ± 10.8 (range, 32.7 – 86.3) at the time of surgery and the predominant preoperative diagnoses was osteoarthritis (97.8%). 72% were solid cups without screw augmentation and 28% were multi-hole with screw. Clinical analysis included Hospital for Special Surgery (HSS) hip scores at latest follow-up. Detail radiographic analysis was carried out on anteroposterior and false profile views for evidence of osseointegration in all Charnley's zones. Osseointegration was assessed based on presence of Stress Induced Reactive Cancellous Bone (SIRCaB) with trabecular bone hypertrophy 5–15mm extending from the cup, and absence of radiolucency or demarcation. EBRA software was used to assess cup positioning. Results. At final follow up, clinical result were excellent with average HSS score of 34.8. 4% underwent revision for following reasons: dislocation (1.34%), loose stem (0.89%), stem fracture (0.89%), pain/bursitis (0.45%), and infection (0.45%). There were no revisions for failures of fixation. In radiographic analysis, the average functional cup abduction angle and functional anteversion were 41.7° ± 5.2 (range, 30 – 52) and 16.8° ± 6.1 (range, 4 – 30). 96% of the cups were within the safezone of Lewinnek. There was no progressive radiolucency, migration or change in the cup position at final follow-up. The average overall SIRCaB and radial trabeculae in all 3 zones were 47% and 93%, respectively; both were most prevalent in Zone 1. Conclusion. The hemispherical, peripheral press-fit, HA-coated PSL cup has excellent safety and efficacy, appropriate radiographic osseointegration with no mechanical failures at 5 – 9 years. PSL cup has 1 mm increase in the radius at the periphery of the shell to allow for an enhanced initial press fit. Based on our results, supplementary screw with this cup may not lead to better fixation

Introduction. All current methods of cup placement use anterior pelvic plane (APP) as the reference. However, the majority of studies investigating the measurement of anteversion (AV) and abduction angles (AA) are inaccurate since the effect of pelvic tilt and obliquity are not considered. The aim of this study was to describe a reproducible, novel technique for functional cup positioning using internal and external bony landmarks and the transverse acetabular ligament (TAL). Methods. The pelvic obliquity and tilt are measured on the pre-operative weight bearing AP and lateral pelvic radiographs. Intra-operatively, the highest point of the iliac crest is identified and a line is drawn to the middle of the greater trochanter with knee flexed to 90 degrees and leg thigh horizontal to the floor, parallel to the APP. The cup is placed parallel to the TAL and inside the anterior acetabular wall notch, and then is adjusted for the femoral anteversion, pelvic tilt and obliquity. The angle between the drawn line and the cup handle is the operative anteversion. 78 consecutive total hip replacements (76 patients) were performed using this technique. The functional cup orientation was measured on post-operative weight bearing pelvic radiographs using EBRA software. Results. The mean follow-up was 1.2 ± 0.3 years. There were no fracture, dislocation or infection. The mean functional AV and AA were 17.9° ± 4.7° (7.8–28.7) and 41.7° ± 3.8° (33.4–50), respectively. The mean pelvic tilt and obliquity were −3.1° ± 9.7° (−25–9) and −1.5° ± 3.2° (−9.9–7.4), respectively. 96% of functional AV and 100% of functional AA measurements were within the safe zone. Discussion and Conclusion. This is an easy, accurate, and reproducible technique, which uses bony landmarks and TAL, adjusted for femoral anteversion and pelvis tilt and obliquity. Weight-bearing radiographs should be used to standardise the measurements with the goal to reproduce the functional cup orientation within the safe zone

Background. Reasons for revision of metal-on-metal hip resurfacing arthroplasty (MoMHRA) have evolved with improving surgical experience and techniques. Early revisions were often due to fracture of the femoral neck while later revisions are associated with loosening and/or adverse local tissue reactions (ALTR) to wear debris. In some studies, revisions of MoMHRA with ALTR have been complicated by an increased risk of rerevision and poor outcome. The purpose of this study was to investigate the causes of failure and to identify factors that improve outcome following revision of a failed HRA. Methods. From 2001 to May 2015, 180 consecutive HRA revisions were performed in 172 patients. Ninety-nine primary surgeries were done at a HRA specialist centre (99/4211, revision rate: 2.4%), 81 elsewhere. Eight different HRA designs were revised mainly in females (60%). Components’ orientation was measured from radiographs using EBRA. Ion levels were used as a diagnostic tool since 2006 (n=153). Harris-Hip-Score (HHS) was obtained prerevision and at latest follow-up. The initial experience of the first 42 cases (Initial Group) was compared to cases 43–180 (Later Group). Patients of the Later group were noted to have less soft tissue damage, had significantly bigger THA heads implanted at surgery, were educated of the increased complication risk and some wore an abduction brace for 6 weeks. Results. All patients presented with some pain/discomfort. Mean time to revision was 38 months (0–160). Eight HRAs were revised for fracture and 8 for infection. The most common reason for revision was component malpositioning (acetabular 48%, excessive abduction and/or anteversion; femoral 10%) usually associated with high metal ions (62%). The most common intra-operative finding was ALTR (48%) followed by metallosis (36%) and impingement (29%). Metal sensitivity was suspected in 8 patients (6F/2M). There were gender-specific differences in component sizes and causes of failure, with a higher incidence of component malpositioning, osteolysis and elevated metal ions in women. Time to revision in patients with high metal ion levels was shorter with the ASR (21 months, SD:10) in comparison to the BHR (38 months, SD: 25) (p=0.05). For the whole cohort, HHS significantly improved post revision (93, 42–100) (p<0.001). Fourteen complications (9 dislocations; 5 infections) and 9 re-revisions occurred. Outcome {HHSpost-op (p=0.04), complication and re-revision rates (p=0.005)} was significantly better in the Later Group compared to the Initial group. The incidence of complications/re-revisions significantly reduced since the introduction of metal ions (p=0.004). The presence of ALTR did not significantly affect outcome (p=0.65). However, patients with ALTR in the Later group (n=51) had significant reduced complication(p=0.005) and re-revision(p=0.016) rates in comparison to those in the Initial Group. Conclusion. Component malpositioning is the most common cause of HRA failure. Metal ion measurements are an excellent tool to detect wear at an early stage. The revision analysis highlights the importance of surgical experience, indications and prosthesis design. Use of ion levels, big THA-heads and patient education/compliance were identified as factors improving outcome following HRA revision. Patients with soft tissue reactions can have good outcome if operated prior to extensive soft tissue destruction

Introduction. Although femoral neck fractures remain a concern in short term failures for hip resurfacing, acetabular component position and fixation are increasingly being recognized as causes of mid term failures for hip resurfacing. This study aimed to evaluate the migration pattern of a cobalt chrome, beaded acetabular component for a metal on metal hip resurfacing. Methods. 130 patients underwent metal on metal hip resurfacing: 66 hips in 60 patients had sufficient films to be included in this analysis. Forty-eight patients were male and 12 were female, with a mean age of 50 (range, 32–66). Ninety-five percent of the procedures were performed for osteoarthritis. In all cases acetabular migration was measured both vertically and horizontally, on serial radiographs using the computer-assisted Ein Bild Röntgen Analyse method. A minimum of three comparable radiographs is necessary for calculating the migration curves. We scored medial migration as negative horizontal movement. Results. At a mean follow up 25.3 months (24–36 months), each hip had an average of 5.1 radiographs for analysis. 12.5% of the cups showed more than 1 mm migration in the medial-lateral axis and 45.3% more than 1 mm in the vertical axis. 23% of the cups showed a combined migration of greater than 2 mm in the observation period. Two of these cases required revision for aseptic loosening at 34 months. Discussion and Conclusion. Previous studies have shown EBRA to have an excellent sensitivity and positive predictive value for mid to long term cup failure. This data raises concern about the initial stability if this acetabular component. Continued follow-up is needed to monitor the longer term survival of this implant