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.

This Outcome Studies Software suite has been designed and carried out by Surgeons for Surgeons in order to provide the Orthopaedic Community with a valuable tool devoted to the computerized clinical follow-up of Joint Arthroplasty, named OrthoWave(tm). The development of the OrthoWave(tm) suite, since 1996, has got involved clinical studies coordinators, software engineers, orthopaedic surgeons, and statisticians.

One underlying theme regarding Health Care has and always will be constant: the need to understand if our treatments actually work. Providing answers makes not only scientific sense but pragmatic and economic sense as well. In such a way, Evaluation in Joint Arthroplasty has become a master word in the realm of Orthopaedic Surgery, which thus gets many actors involved, be they Surgeons, Scientific Societies, Health Department Authorities, Journal Editors, and Orthopaedic Devices Manufacturer.

While bearing in mind that more than a million of Hip and Knee replacements are worldly performed annually and there are thousands of devices and device combinations in use to achieve arthroplasties, these replacement procedures have to be properly evaluated as a very challenging procedure. An outcomes study software needs to allow for easy and user friendly collection of clinical data and related images, while preserving privacy of patients and their personal data. This software must then provide consistent statistical and survivorship analyzes in the very long run. The OrthoWave(tm) software has been widely used worldly, and currently features the on-line Version 6, now available as a web-based secured “cloud computing” computer system. The so called “regular databases” can be linked to additional “scientific databases” and “monitored databases” able to set up together a very consistent and efficient global system.

Roughly speaking, OrthoWave addresses (1) data collection of Surgeons themselves, able to self evaluate their surgeries while owning their own data, (2) Local Registries, involving groups of Surgeons, to analyze, report and publish clinical series in the Literature, (3) Brand Registries, for tracking upon large multicenter studies at an early stage any problem that might occur with any given implant, (4) Clinical Affairs Departments in Industry, (5) and finally enables potential automatic links to National and International Joint Registries.

This OrthoWave software has thus permitted a “fine tuning” of clinical results, radiographic findings, survival rates and real assessment of quality of life, helping to determine in large databases studies if implant composition or joint replacement features can be associated with decreased need for repeat surgery, and to outline best methodological approaches to the assessment of failures in arthroplasty, in terms of functioning, quality of life and long-term disability.

All along these 14 years of continuous use of this OrthoWave software suite, we have tried to help it to be more and more efficient and user friendly. The current on-line web-based version now meets our expectation, and is flexible enough to adapt itself to future needs and better treatments for patients.

This study describes 146 primary total knee replacements, either fully or partially coated with hydroxyapatite of which 74 knees in 68 patients were available for clinical and radiological assessment at a mean of 11.2 years (10 to 15). The global failure rate was 1.37% and survival rate with mechanical failure as the end-point was 98.14%. Radiological assessment indicated intimate contact between bone and the hydroxyapatite coating. Over time the hydroxyapatite coating appears to encourage filling of interface gaps remaining after surgery. Our results compare favourably with those of series describing cemented or porous-coated knee replacements, and suggest that fixation with hydroxyapatite is a reliable option in primary total knee replacement.

Purpose: Despite excellent histological and biomechanical results proving the real efficacy of “biological” implant-bone fixation, use of hydroxyapatite surfacing, widely used for hip implants, remains largely unemployed for knee prostheses. We analysed our ten years experience with hydroxyapatite coated knee implants in a prospective study of 384 cases.

Material and methods: Among the 384 prostheses, 361 were primary implantations, and 331 (92%) were still “in place” after ten years experience. Nineteen patients had died and only one (0.3%) was lost to follow-up; three patients were excluded from the analysis due to other major handicaps. There were five revision procedures including three (0.8%) related to deep infection and two (0.6%) to failure with loosening and pain. Mean age of the patients was 70.4 years (40–89). Indications were basically degenerative disease (91%), inflammatory rheumatoid disease (6.9%) and necrosis (1.7%).

Results: Mean IKS score at five years minimal follow-up for primary surgery patients was 95.4 and 84.2 points for the overall knee score and the functional score respectively, giving 81.1% and 73.1% good and excellent results for the knee and functional score.

Discussion: These clinical results compare well with the best studies reported on total knee arthroplasty with or without cement. Radiographically, we did not have any cases with evidence of an implant-bone interface problem, for femoral or tibial components with the exception of two knees (0.55%) with severe osteolysis and loosening leading to revision surgery. In addition, hydroxyapatite demonstrated its capacity to progressively fill bone-implant gaps over time, confirming the experimental work by Søballe. Cumulative survival was 96.6±0.0688% and 97.37 ± 0.0324% taking ablation and prosthesis-related failure as the endpoint respectively.

Conclusion: These results allow renewed confidence in hydroxyapatite as a prosthesis fixation mode, for the knee as well as for the hip.