Clinical results, radiological findings and survival of a proximally hydroxyapatite-coated hip ABG II stem at a minimum of ten years' follow-up: results of a consecutive multicentre study of 1148 hips in 1053 patients

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 hydroxyapatite-coated implants in revision surgery for acetubular component loosening

Since 1989,the authors have used the Hydroxyapatite (HA)-coated ABG prosthesis for both primary and revision hip replacement. Hydroxyapatite is osteoconductive, and therefore speeds up bone formation and ensures a direct contact between the implant and the host bone, without any interposed fibrous tissue. The cup can thus be firmly fixed in the bony acetabulum, with eventual osseointegration into the host bone. The quality of the results achieved, at primary hip replacement, with bioactively coated devices has been highlighted in a large number of publications.

[Single-compartment knee arthroplasty prosthesis and idiopathic necrosis of the medial tibia surface]

PURPOSE OF THE STUDY

Idiopathic necrosis of the medial articular surface of the tibia is exceptional. Diagnosis is quite difficult and often made late. Among the different treatments proposed, we preferred single-compartment arthroplasty.

MATERIAL AND METHODS

We report 8 cases in women with a mean age of 71.1 years. Diagnosis was suspected due to drug-resistant knee pain, particularly frequent at night, initially with radiographically normal knees. The first radiographic signs, seen 3 months after the onset of pain, were pathognomonic for osteonecrosis evidencing subchondral defects of the tibial surface with a dense peripheral rim and apparently "sequestered" in a notch. Bone scintigraphy evidenced intense uptake in the medial compartment. MRI confirmed the diagnosis evidencing a band of low intensity signals completely surrounding a sequestered zone reaching the cortical. This band was stable and irreversible. In 5 cases CT scan and in 3 cases tomography identified the width and height of the necrotic area that was limited to the medial compartment in all cases. All patients were treated with a single compartment implant. The diagnosis of necrosis was confirmed at pathology.

RESULTS

At 4,6 years of mean follow up all patients had an excellent outcome, "forgetting" their knee. No lucent lines developed along the femoral or tibial implants.

DISCUSSION

Necrosis of the medial articular surface of the tibia is exceptional and often diagnosed late by bone scintigraphy or MRI. Surgical treatment is usually based on tibial osteotomy for valgisation or a single or three-compartment prosthesis. In our 8 cases, the necrosis was limited to the medial compartment, warranting our therapeutic option.

[Unicondylar fractures of the femur]

The authors have treated and reviewed 8 recent and 24 ancient unicondylar fractures of the femur. They point out that initial diagnosis had often been missed, due to associated lesions or apparently minimal displacement. They think that recent fractures should always be surgically treated by sagittal screwing. Indications are given for the treatment of malunions (osteotomies, arthrolysis, arthrodesis, prosthesis).