HIP International

Ceramic-on-ceramic (CoC) couplings are alternative bearings surfaces that have been reported to reduce osteolysis, wear debris and aseptic loosening compared to the use of polyethylene. Early experiences with ceramics had poor results, but they have led to many improvements in the manufacture and design of subsequent implants.

We analysed medical files of 300 CoC total hip arthroplasty (THA) with a modular neck performed during period 1995-2000 by a single surgeon for a minimum follow-up of 13 years, evaluating clinical and radiological outcome.

The mean clinical Merle d'Aubigne and Postel hip score at the final follow-up is 17.4, against a pre-operative value of 11.4. Overall survivorship with an endpoint of revision is 93.2% (95% CI, 89.0%-97.3%) at 15 years, while considering only prosthesis failures related to aseptic loosening and ceramic breakage, survival rate at 15 years is 97.2% (95% CI, 94.8%-100%). We observed complications that led to revision surgery in 11 patients (4%) (periprosthetic fractures, liner ruptures, septic loosening of the implant, aseptic loosening of the cup, aseptic loosening of the stem). The occurrence of squeaking is low (1.6%, 4 cases) and we analysed the characteristics of these patients.

Our study shows an excellent long term survivorship of third generation alumina CoC THA. We reiterate the importance to have a stable implant to maximise the advantage of ceramic and to avoid complications.

The sensitivity of cobalt (Co) and chromium (Cr) ion-levels in detecting poorly performing metal-on-metal hip implants is low. This study proposes that serial changes in ion-levels are a more accurate marker of arthroplasties at risk.

Serial metal ion-levels and implant data of 285 patients with ASR resurfacing or replacement were studied. Patient and implant characteristics were analysed using univariate and multivariate analyses.

111 (39%) had revision surgery. Time since index surgery (p≤0.001), acetabular inclination (p≤0.001), their interaction (p≤0.001) and femoral head size (p = 0.01) were significant variables. Head size (≤51 mm) had lower Co and Cr levels (p = 0.01). Cr/Co showed marginal decrease over time in the unrevised group and no decrease prerevision.

Repeated measurement of ion-levels were higher in the revision group suggesting that serial measurements rather than absolute values may have a role to play in predicting implant failure.

Modular necks in total hip replacement (THR) can be a source of metal ion release.

We measured the level of cobalt (Co) and chromium (Cr) ions in the serum of 23 healthy volunteers with a well-functioning ceramic-on-ceramic THR of a particular design, containing a cobalt-chrome (Co-Cr) stem and a Co-Cr modular neck.

Average Co in serum was 1,71 μg/l; median Co was 1.50 μg/l. No patient had Co levels higher than 3.70 μg/l. Average Cr level was 0.49 μg/l; in all but one patient Cr was below the detection limit (≤0.50 μg/l). Co was higher for varus necks compared to all other subtypes: 2.14 μg/l vs 1.58 μg/l (p≤0.05). The same system with Titanium modular necks shows lower Co serum levels: 1.26 μg/l (p≤0.01). In conclusion, the hybrid THR Profemur Xm® – Procotyle L® with a Co-Cr modular neck on a Co-Cr stem design shows very low Cr ion serum levels in a randomly selected group of well-functioning hip patients.

Co ion serum levels are low, but significantly higher for 8° varus necks, and Co levels are significantly higher than values of this system with a Titanium modular neck.

Periprosthetic bone loss may lead to major complications in total hip arthroplasty (THA), including loosening, migration, and even fracture. This study analysed the influence of femoral implant designs on periprosthetic bone mineral density (BMD) after THA.

The results of all previous published studies reporting periprosthetic femoral BMD following THA were compiled. Using these results, we compared percent changes in bone loss as a function of: femoral stem fixation, material, and geometry.

The greatest bone loss was in the calcar region (Gruen Zone 7). Overall, cemented stems had more bone loss distally than noncemented stems, while noncemented stems had more proximal bone loss than cemented stems. Within noncemented stems, cobalt-chromium (CoCr) stems had nearly double the proximal bone loss compared to titanium (Ti) alloy stems. Finally, within noncemented titanium alloy group, straight stems had less bone loss than anatomical, tapered, and press-fit designs.

The findings from the present study quantified percent changes in periprosthetic BMD as a function of fixation method, alloy, and stem design. While no one stem type was identified as ideal, we now have a clearer understanding of the influence of stem design on load transfer to the surrounding bone.

The purpose of this study was to analyse the extent of surgical correction and the early clinical results obtained using periacetabular osteotomy with allogenic bone grafting in patients with severe acetabular dysplasia.

44 hips in 38 patients were confirmed to have severe acetabular dysplasia and underwent this procedure. The mean follow-up period was 4.2 (range 1.5-8.2) years. Severe acetabular dysplasia was defined as a centre-edge angle less than 0°, an acetabular-head index less than 50% and an acetabular roof obliquity greater than 30°. Periacetabular osteotomy was performed with transpositional osteotomy of the acetabulum. The patients were divided into 2 groups according to the radiographic appearance: 34 hips in the early stage group and 10 hips in the advanced stage group. Postoperatively, the hips were radiographically assessed for dysplasia correction. The clinical results and hip function were measured using the Harris Hip Score.

The average pre-operative Harris Hip Score improved from 70 to 91 points at the latest follow-up. The average centre-edge angle, acetabular-head index and acetabular roof obliquity improved from −9° to 36°, 41% to 91% and 31° to 2°, respectively. Continuity of the Shenton line improved from 15 to 35 hips. No instances of nonunion or of transported segment collapse were encountered in this series; however, a grafted allogenic bone was absorbed in 1 case.

The usage of allogenic bone grafting combined with periacetabular osteotomy is an effective technique for treating severe acetabular dysplasia. In this series, the early clinical and radiographic results were excellent.

The purpose of our study is to identify complications and early functional outcome scores in patients treated with periacetabular osteotomy (PAO) for mild acetabular dysplasia.

The study population consisted of patients from a single centre prospective hip registry undergoing PAO with mild acetabular dysplasia (LCEA ≥18° and ≤25°; n = 27 patients; Mild Dysplasia group). A comparison group of patients undergoing PAO with more severe acetabular dysplasia (lateral centre-edge angle [LCEA] ≤17°; n = 50 patients; Severe Dysplasia group) were included as a comparison cohort. Demographics, radiographic findings, complications, and functional outcome scores were recorded at 6 months, 1 year, and 2 years postoperatively (mean 15 months [range 6-30]).

Demographic characteristics were similar in patients with mild dysplasia undergoing PAO compared with more severe dysplasia. Achievement of radiological correction and complication rates were not different between the 2 groups. Functional outcome scores showed similar improvements in modified Harris Hip Score (mHHS), hip outcome score (HOS) activities of daily living (ADL), HOS Sport, and the international Hip Outcome Tool-33 (iHOT-33) at all time points between the 2 groups with over 90% of patients in the mild dysplasia group achieving a minimum important change (MIC) in functional outcome scores at final follow-up.

Patients with symptomatic mild acetabular dysplasia undergoing PAO have similar complication rates and functional outcomes as a cohort of patients with more severe dysplasia.

Eccentric rotational acetabular osteotomy (ERAO) is a modification of rotational acetabular osteotomy (RAO); it has been reported that ERAO allows the femoral head to translate medially and distally. However, no study has compared femoral head translation following RAO or ERAO. The purpose of this study was to compare immediate postoperative translation of the femoral head after RAO and ERAO in comparison with the pre-operative position by radiological methods.

Patients treated by RAO or ERAO between 2006 and 2014 were retrospectively evaluated. 19 hips (17 patients) were treated with RAO, and 25 hips (22 patients) were treated with ERAO. The acetabular roof angle and the location of the femoral head were measured on anteroposterior pelvic radiographs.

The mean pre-operative acetabular roof angle was 20.9° in the RAO group and 22.0° in the ERAO group, showing no significant difference. The mean acetabular roof angle immediately postoperatively was −0.5° in the RAO group and −0.4° in the ERAO group, again showing no significant difference. The mean femoral head translation immediately postoperatively was 3.1 mm (95% confidence interval (CI), 1.5-4.7 mm) laterally and 3.0 mm (95% CI, 1.3-4.7 mm) proximally in the RAO group and 0.8 mm (95% CI, −0.7-2.3 mm) medially and 2.8 mm (95% CI, 1.5-4.1 mm) distally in the ERAO group; this difference was very highly significant (p≤0.001).

In contrast with RAO, ERAO resulted in significant femoral head translation both medially and distally immediately postoperatively.

When performing total hip arthroplasty (THA) on a dysplastic hip, proper positioning of the acetabular component may not allow for more than 70% coverage. Structural support in the form of an autograft or a high porosity metal augment may be necessary. The purpose of the study was to investigate the value of pre-operative templating and deformity classification in predicting cup coverage and the need for structural support.

65 cases of THA for DDH were retrospectively analysed. 2 observers independently classified each dysplastic hip according to Hartofilakidis and determined the extent of cup coverage via templating software on pre-operative digital AP pelvic radiographs.

Weighted kappa interobserver agreement was 0.68 for cup coverage and 0.76 for Hartofilakidis type. Structural support was necessary in 10 hips. No structural support was necessary in Hartofilakidis type 1, dysplasia cases. However, 27-30% of cases with type 2 or type 3 dysplasia required structural support. All cases with templated cup coverage of 65% or less required structural support. Templated coverage within 65-75% and over 75% resulted in 20% and 10% of patients receiving structural augmentation, respectively.

Pre-Operative planning for THA in the setting of hip dysplasia is crucial and can provide valuable insight to the need for column augmentation. However, the 3-D severity of the deformity may be underestimated in the 2-D radiographs.

Recent reports indicate that total hip arthroplasty (THA) can be further accelerated and might be managed as day-case. This could provide benefits to health care expenditure, lower patient risks and change patient satisfaction. We evaluated the feasibility, efficacy, safety and patient satisfaction of same-day (≤12 hours) THA operation and discharge.

Consecutive patients were screened for eligibility (primary THA, ASA 1 or 2 physical status) and the presence of a support person to follow the patient for 48 hours postoperatively in an observational study. THA was managed as day-case (≤12 hours) through patient selection, pre-operative patient education programme, light spinal anaesthesia, low opioid usage, and early mobilisation. Efficacy and logistics were analysed and compared to current accelerated practice. Patient satisfaction was compared to existing fast-track THA and elective surgery cohorts.

29 consecutive patients were screened and 20 participated (69%). 17/20 patients (85%) were released on the day of surgery. There were no serious adverse events or complications, and no infections or readmission at 6-week follow-up. Patient overall satisfaction rating (1–5) was high (4.75), higher than in a 301-patient cohort (4.53) (THA and total knee arthroplasty) from the same centre (p = 0.23), and higher than in a national, elective surgery cohort (4.3) (p = 0.04).

We report the feasibility of day-case THA. Safety, complications and overall patient acceptance were satisfactory. Light spinal anaesthesia facilitated quick transit through postanaesthesia care unit to early mobilisation. Support persons and patient education may play a part in high patient acceptance of day-case surgery.

The current study was designed to describe types of histological changes within the acetabular labrum in the advanced stages of coxarthrosis, in patients requiring total hip arthroplasty (THA).

77 consecutive patients without systemic disorders or prior hip surgery, scheduled for THA with 3 types of coxarthrosis: avascular necrosis (AVN), idiopathic, and dysplastic coxarthrosis were analysed. Patient's data: age, gender, side of the involvement, duration of the symptoms were recorded, and standard anteroposterior (AP) radiographic views of the pelvis were obtained. During THA procedure the acetabular labrum was harvested and examined histologically and immunohistochemically. The mean chondrocytes number and density were calculated using morphometric techniques.

In 77 analysed acetabular labra the following histological changes were found: heterogenic matrix, foci of granular matrix breakdown, pseudocysts, intralabral c alcifications, chondrocyte apoptosis, inflammatory reaction with lymphocytes infiltration and macrophages infiltration and vascular proliferation with 2 stages of maturation: endothelial cell formation and fully formed blood vessels. The average chondrocytes density was 478 cells in 1 mm² and significantly decreased with age.

The acetabular labrum is an important part of the process of degeneration of the hip in osteoarthritis (OA). Vascular formation and cellular infiltration found in the damaged fibrocartilage may represent a labral response to degenerative changes.

Numerous salvage surgeries were popularised to halt the progression of hip osteonecrosis (ON). We aimed to compare the clinico-radiological outcomes of inverted femoral head graft (IFHG) versus standard core decompression (SCD) in treatment of nontraumatic hip ON at pre-arthritic stage.

A case review was performed at a minimum 3 years follow-up of 61 patients (71 hips; mean age 32.96 (19-50) years; mean follow-up 7.86 (3-14) years; mean body mass index 28.58 (19-46); 32 males, 29 females) suffering nontraumatic hip ON at pre-arthritic stage. 38 hips underwent SCD and 33 IFHG. The outcome was assessed by changes in modified Harris Hip Score (MHHS), need for revision surgery and progression of modified Ficat-Arlet staging. Data were analysed including logistic regression and Kaplan-Meier survivorship analysis.

13/34 (38.2%) hips in SCD group were revised at 4.61 ± 2.61 years, while 7/33 (21.2%) in IFHG group at 8.43 ± 4.32 years (p = 0.023). MHHS was significantly higher in IFHG group at 1 and 3 years as well as at last follow-up (p = 0.014, 0.001 and 0.023 respectively). Clinical and radiological significant differences were found in survivorship analysis between both groups, in favor of IFHG. A higher clinical failure was noted among obese patients.

An IFHG technique offers a better alternative regarding postoperative clinico-radiological outcomes in nontraumatic hip ON at the pre-arthritic stage. A cautious prognosis is recommended in obese patients.

To assess the accuracy of a novel digital templating methodology for total hip arthroplasty (THA) in patients with osteonecrosis of the femoral head (ONFH).

A retrospective study was carried out on 77 hips in 58 patients who had undergone uncemented THA for ONFH. Pre-Operative radiographs were templated using a 2-step procedure: (i) calculation of basic cup and stem sizes based on the anatomical morphology; (ii) adjustment of the basic sizes to account for variables such as femoral external rotation, osteoporotic changes in the femur, osteosclerotic changes in the acetabulum, and the type of stem. Basic and adjusted sizes were compared with the actual sizes of the implants used.

Before adjustment, the overall accuracy was 69% and 70% for stem size and the cup respectively. Among all the cases, 31 femoral components (40%) and 17 acetabular components (22%) required adjustment. After adjustment, the accuracy of templating for stem and cup sizes in these adjusted cases improved from 52% to 87% (p = 0.002), and 41% to 82%, respectively (p = 0.032). And the overall templating accuracy improved to 83% on the stem side (p = 0.038) and 79% on the cup side (p = 0.195).

Pre-Operative digital templating was useful in predicting cup and stem sizes in patients with ONFH. Radiographic signs of femoral rotation or osteoporotic changes call for appropriate adjustment to improve the accuracy of templating for THA.

The purpose of this study was to compare the usefulness of measuring acetabular anterior coverage by tomosynthesis and false profile (FP) radiography.

70 hips in 35 patients who were diagnosed with early stage osteoarthritis of the hip, and 60 hips from 30 healthy volunteers were analysed. Plain FP radiographs were taken, and vertical-centre-anterior margin (FP-VCA) angles were measured. Acetabular anterior coverage was measured in the natural standing position using a tomosynthesis imaging system in the sagittal plane. As with FP radiography, we measured vertical-centre-anterior margin (TS-VCA) angles.

The median values of the FP-VCA angle, and TS-VCA angle were 43.8°, 54.4°, respectively. The TS-VCA angle was significantly larger than the FP-VCA angle. For FP radiographs, the intraobserver intraclass correlation coefficient (ICC) was 0.68, and the interobserver ICC was 0.79. For tomosynthesis sagittal images, the intraobserver ICC was 0.85, and the interobserver ICC was 0.92. There was a strong positive correlation between the TS-VCA angle and the FP-VCA angle. When the FP-VCA angle was 25°, the TS-VCA angle was 35° in regression analysis.

Measuring acetabular anterior coverage using sagittal plane tomosynthesis correlates well with FP radiography. Regardless of the presence of acetabular deformities, tomosynthesis demonstrated high reproducibility, simple posture setting, low effective doses, and high versatility. A cut-off value of 35° was useful for the detection of developmental dysplasia of the hip joint using the TS-VCA angle.

Legg-Calvé-Perthes disease (LCPD) is a paediatric form of osteonecrosis that ultimately heals but will cause femoral head and acetabular deformities. The purpose of this study was to investigate the early serum measurement of osteocalcin in children with femoral head necrosis compared with that of healthy children.

20 patients with LCPD (4 girls and 16 boys) and 20 healthy volunteers (5 girls and 15 boys) were enrolled. All patients did not have additional treatment. Blood samples were obtained from all patients pre-operatively in the morning. All cases had hip radiographs. The serum levels of osteocalcin comparisons between the LCPD patients and the healthy volunteers were performed using Wilcoxon signed-rank test. The Spearman rank correlation was used to assess correlation between LCPD grade and serum osteocalcin levels. Significance was set at p = 0.05.

The 20 patients with LCPD (72.75 ± 24.92 ng/ml) had significantly higher serum osteocalcin levels compared with the healthy group (16.80 ± 4.04 ng/ml) (p≤0.01). Serum osteocalcin levels of different LCPD grades were significantly different (Spearman's p = 0.540, p = 0.014).

We observed a significant correlation between serum osteocalcin levels and LCPD. These results may be meaningful in clinical practice and to future studies.

To compare 4 different bearings in total hip arthroplasty (THA) in a randomised controlled clinical study on clinical performance.

393 patients with osteoarthritis of the hip or avascular necrosis were included and allocated to 1 of the head-and-cup couples zirconia-on-polyethylene (group A), metal-on-metal (group B), zirconia-on-polyethylene with the liner moulded into the shell (group C), or alumina-on-alumina (group D). In the individual case the surgeon could choose other implants if indicated.

299 patients were operated with the allocated prosthesis. The estimated cumulated prosthesis survival percentages and 95% confidence interval after 10 years were: group A 84.6 (75.8-93.4); group B 95.0 (89.5-100); group C 93.2 (86.7-99.7); group D 66.1 (54.5-77.7). The patients' physical function was significantly improved and remained equally good in all 4 groups, however slightly declining with ageing. The luxation rate was initially high, and equal between the groups, but was reduced by improving the surgical procedure introducing capsule repair by reinsertion of the short external hip rotators.

The metal-on-metal or zirconia-on-polyethylene prostheses had high 10-year survival percentages. The longevity of these bearing couples by themselves was not related to the combination of materials. The zirconia-on-polyethylene prosthesis with the liner mounted peroperatively possibly exhibited cases of backside wear which the corresponding bearing couple with moulded polyethylene (Asian) did not. The alumina-on-alumina bearing performed poorly - it was redesigned after our study initiation and later withdrawn from the market.

Repairs of labral tears are performed for unstable tears, hip instability, and after detachment concomitant to the treatment of femoroacetabular impingement (FAI), but limited data is known about the strength of repair. This study evaluated the effect of simulated axial weight-bearing on suture anchor based repair of the acetabular labrum.

3 cadaveric pelvises underwent creation of a 1.5 cm anterior-superior labral tear in each hip. The tears were then repaired using 2 suture anchors per hip. Following repair, the hip joint underwent axial cyclic loading to 756 N, and were inspected for separation of the labrum from the acetabulum. The strength of the suture anchor repair was evaluated by testing load to failure, in-line with insertion.

Upon visual examination, all 6 repairs remained fully intact following loading with no visible gap formation or damage at the repair site. In all cases an arthroscopic probe could not be inserted under the edge of the repair. The mean failure force of the 12 suture anchors, in-line with insertion, was 154 N ± 44 N.

Acetabular labral suture anchor repairs may be able to immediately withstand the physiological loads of axial weight-bearing. Labral repair may be able to tolerate axial weight-bearing immediately after repair, preserving the strength and integrity of muscles and soft tissues.