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.

The use of a total hip arthroplasty with alumina on alumina bearing couple should limit the risk of wear and secondary osteolysis. From June 1999 to December 2002, we have realised a continuous series of 265 ABGII cementless THA with Alumina bearing.

The average age was 58 years (22–78 years). The main causes were osteoarthritis (81%) and osteonecrosis (13%). The operation was performed through a posterior standard approach. In all cases, an anatomic cementless ABG II stem and an acetabular cementless ABG II cup were implanted. The bearing couple was always Alumina Biolox Forte with a 28 mm femoral head in 99% of cases. To date, 12 patients died and 17 patients were lost to follow up (6.4%). 224 patients (232 hips) had a regular clinical and radiological follow-up. The mean follow up was 8.5 years (5–11 years). 9 patients were revised for septic loosening (4cases), femoral fracture (4 cases) and inveterate dislocation (1 case). There was no aseptic loosening. The overall survival rate at more than 10 years is 96.6%. We deplore 2 cases of postoperative dislocation. In this series, we did not observe any breakage of ceramic implant. The clinical and functional outcome is good and stable over time with an average PMA score at 17.6 and an average Harris score at 97.3. 16 patients reported at least one or more episode of abnormal noise “Squeaking” type (6%). It is most often a mild noise and it occurs in a static bending position. This noise disappeared with time in 10 cases. It never necessitated a prosthetic revision. The radiological control does not show any wear. There is no evidence of acetabular or femoral osteolysis. The radiological implant fixation according to the Engh and ARA criteria was good and stable in all cases.

This series demonstrate that the implantation of an anatomic cementless HA arthroplasty with an alumina bearing in a young and active patient prevents the risk of wear and osteolysis and improves durability over time. The use of a 28 mm head does not increase the risk of instability and we did not observe failure of the ceramic implants.

Purpose of the study: Implanting a femoral stem with a modular neck can modify the range and the position in space of hip rotation arcs. The purpose of this work was to evaluate changes in three versions of a modular neck and to define the determining criteria for the choice of the neck to implant.

Material and method: This series included 52 primary modular THA (ABGII) with ceramic bearings implanted with the HipNav 1.3 navigation system. The range of hip rotation were measured referring to the femoral saggital plane and the anterior pelvic plane. After insertion of the cup and the final ABGII stem and after choosing the length of the modular neck and the frontal inclination, the three different versions (retroversion −7, neutral 0 and anteverion +7) were tested. The range of hip rotation was measured by dynamic testing done under navigation. At the same time, the surgeon evaluated the stability and the absence of posterior impingement.

Results: In extension, mean range of rotation was 71° (102–123). It was modified by neck version. The position of the centre of rotation in relation to the reference rotation (rotation 0) depended on the version of the modular neck. The balance of the rotational arcs was better with a retroversed (−7) neck (mean centre of rotation -9) with a neutral neck (centre -13) or an ante-versed (+7) neck (centre-20). The determining factors were the version of the femoral stem and the combined (cup+stem) version. After checking the stability, the surgeon chose an anteversed neck in three cases (5.7%), a neutral neck in 25 (48%) and a retroversed neck in 24 (46.3%). The choice of the modular neck maintained the ligament balance in 71% of the hips.

Discussion: This demonstrates that the use of a prosthesis with a modular neck enables modulation of the rotational balance of the hip. This work demonstrates that work on balancing the rotational arcs of the hip in extension is a reliable operative criterion for choosing the version of the modular neck without using a navigation system.

Introduction: A femoral stem with a modular neck can optimize the range of motion (ROM). The hip’s maximal rotational ranges were evaluated with three different modular neck versions

Methods: This study included 52 primary implantations of a short cementless anatomical modular stem using navigation control. ROM was measured using the sagittal femoral and the anterior pelvic plane as references. Once the cup and stem were implanted, three different neck versions (retroverted: −7°, neutral: 0, and anteverted: +7°) were used. A dynamic test measured the maximal ROM for each patient and neck version. Simultaneously, the surgeon evaluated the stability and the absence of posterior impingement.

Results: The average rotational range in extension was 72° for a retroverted neck, 71° for a neutral neck and 76° for an anteverted neck. This difference was not clinically significant. The equilibrium of the rotational ranges appeared better with a retroverted neck (average center: −6°) than with a neutral neck (average center: −8°) or an anteverted neck (average center: −13°) (p< 0,001). The equilibrium of the rotational range correlated with the femoral stem anteversion (r=−0.70, p< 0.001) and with the combined anteversion (r=−0.74, p< 0.001). Finally, an anteverted neck was used in 3 cases, a neutral neck in 25 cases and a retroverted neck in 24 cases. The surgeon’s final neck version choice obtained the best equilibrium in 60% of cases.

Discussion/Conclusion: The study showed that balancing the hip rotational ranges may be a helpful operative test when choosing a modular neck without a navigation system.

Primary hip arthroplasty performed through a mini incision ( less than 10 cm) should provide more comfortable postoperative period and faster rehabilitation.

After a long period of learning curve ( more than one hundred cases) and development of specific instruments, a prospective comparison between the standard approach technique (38 cases) and mini incision technique (41 cases) was performed. In all cases, the ABG II stem was implanted. It was uncemented in 76% of cases. As it is not randomised, there is a slight difference between the two groups in age (p = 0,03) and body mass index (p = 0,01).

The fonctional status was evaluated at the third and seventh post operative days and at the first and second post operative months. Pain relief (EVA score), total peri operative blood loss (OSTHEO study criteria) and radiologic implants positioning are mesured.

In this study, there was no major complication. There was one case of phlebitis in both groups. During the evaluation, there was no significant difference in the functional result. The post operative EVA pain score was not different. The mean total peri operative blood loss was 1025 ml in the standard approach group and 1164 ml in the mini incision approach group (p = 0,405). The radiologic evaluation showed no difference in the cup positioning. In the mini incision group, there was few cases of varus positioning of the ABG II stem (21% cases) but it was not significant.

Those results demonstrate the safety and the efficacy of the posterior mini incision approach. There is a need for a technical learning curve and a resonably incision sizing adapted for each patient. Under those conditions, we are able to achieve the same quality of implant positioning, which should provide the same long term result.

Hip revision failures are partly due to the poor quality of femoral bone stock. Several work showed that bone reconstruction without grafts is possible around a non cemented, stable stem. It is enhanced by a transfemoral approach.

We designed the Restoration TM DLS stem (anatomical, S curved, HA coating and distal locking to ensure a primary stability).

Preoperative planning is necessary. The operative technique is based on a double postero-lateral femoral flaps approach. An innovating and modular instrumentation was developed. It rests on a femoral clamp that solidarises the femur and the trial stem, and allows a precise adjustment of the length and the stem anteversion. A targeting device allows a precise distal locking of the final implant. Osteosynthesis of the flaps is carried out by cerclages in order to bring the bone around the prosthesis.

Forty-seven revisions cases were followed up. No major peroperative incident has occurred. We report one case of locking error. Compared to the planning, the instrumentation was considered to be precise in 94% for the adjustment of the leg length and of the ante-version. The bone adaptation around the implant was generally correct. In 21 cases, it was necessary to carry out metaphysal re-calibration or osteotomies for correction of a femoral deviation. The synthesis of the flaps is stable in 92%. For follow up greater than 3 months, the consolidation of the osteotomies is effective in 90%.

This study made it possible to validate a surgical procedure by transfemoral approach that makes safe implant and cement removal. It also allowed us to validate an innovating, precise yet flexible instrumentation that allows, after preoperative planning, the anatomical reconstruction of the femur around the stem. A perfect proximal adaptation of the femur to the implant is necessary to the good tolerance of the distal locking.