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.

Purpose of the study: The natural history of congenital hip dysplasia with weight-bearing usually progresses towards degenerative joint disease. The anatomic type of the dislocation, whether treated or not, was well classified by Crowe who described four types.

Material and methods: Since 1989, we have used an ABG hydroxyapatite (HA) coated prosthesis for the treatment of congenital hip dysplasia. The hemispheric acetabular implant is coated with hydroxyapatite and the femoral implant, which is inserted in an anatomic position with anteversion, antetorsion and anteflexion, has a HA-coated stem. Forty-three Crowe type 3 or 4 hips (high position) were treated with this technique:

implantation of the cup in the paleoacetabulum;

Results: Cup implantation in the paleoacetabulum was achieved in all patients except two. A screwed autograft was inserted in 75% and remained stable over time for the larger grafts but tended to resorb for smaller grafts. For femoral anteverions, an ABG implant was used in 34 cases: 21 ABG1 stems, 11 ABF2 stems, and one ABG revision stem. The ABG stem enabled satisfactory anatomic restoration in 20 hips but with postoperative stiffness. For 14 hips, due to the important femoral anteversion related to the dysplasia, a reversed ABG-HA implant was used: eight left implants for right hips and six right implants for left hips. This «reversed» curvature gained 24° in the femoral anteversion plane. The outcome was excellent in these 14 cases, particularly with a clear improvement in postoperative external rotation. At close to 15 years follow-up we have had no case of femoral loosening, nor of femoral shaft osetolysis, with this type of implant.

Discussion: Certain authors propose using a custom-made implant for sequelar congenital hip dysplasia, but we prefer the proposed technique which provides very satisfactory results and limits the need for custom-made material.

Purpose: Reconstruction of massive bone loss with cancellous bone deposited in a pseudomembrane induced by a cemented strut was performed in 40 procedures. We evaluated the 5-year results of this technique for the treatment of gaps measuring more than 5 cm.

Material and methods: We reviewed 12 patients; all had suffered major loss of tibial bone. The operations consisted in resection, insertion of a cement strut, and closure with a local are free flap over he disinfected soft tissues. The second operation at least two years later used a fragmented autologous cancellous graft leaving the membrane intact. The fibula was used as a tutor whenever possible. Bone losses measured 5 to 25 cm in young men who had infection after trauma or, in one patient, tumour resection. We analysed clinical and radiological outcome.

Results: All patients were seen five to ten years after initial management. At last follow-up, all wounds had dried and bone healing was solid. All had required secondary repeated grafts, realignment surgery (for valgus and varus) or operations related to the initial injury (arthrodesis, claw toe). Generally, the patients had resumed their occupational and recreational activities. The walking distance was not limited and single leg stance was painless. The radiological analysis demonstrated a trend towards graft tubulisation.

Discussion: The stut technique using cement induces the formation of a pseudo-synovial membrane. This technique has been used for more than ten years in our unit to treat circumferential defects. Bone healing was achieved in all patients. The main complication was valgus malalignment which almost always requires surgical correction. Rapid healing is not a function of the extent of the gap but rather the radical nature of the resection and the quality of the cover. This technique should be compared with other alternatives used to fill major bone gaps (Illizarov, vascularised bone transfer).

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.