In a retrospective study we compared 32 HINTEGRA
total ankle replacements (TARs) and 35 Mobility TARs performed between
July 2005 and May 2010, with a minimum follow-up of two years. The
mean follow-up for the HINTEGRA group was 53 months (24 to 76) and
for the Mobility group was 34 months (24 to 45). All procedures
were performed by a single surgeon. There was no significant difference between the two groups with
regard to the mean AOFAS score, visual analogue score for pain or
range of movement of the ankle at the latest follow-up. Most radiological
measurements did not differ significantly between the two groups.
However, the most common grade of heterotopic ossification (HO)
was grade 3 in the HINTEGRA group (10 of 13 TARs, 76.9%) and grade
2 in the Mobility group (four of seven TARs, 57.1%) (p = 0.025).
Although HO was more frequent in the HINTEGRA group (40.6%) than
in the Mobility group (20.0%), this was not statistically significant
(p = 0.065).The difference in peri-operative complications between
the two groups was not significant, but intra-operative medial malleolar
fractures occurred in four (11.4%) in the Mobility group; four (12.5%)
in the HINTEGRA group and one TAR (2.9%) in the Mobility group failed
(p = 0.185). Cite this article:
We describe the early results of a prospective study of 100 total ankle replacements (96 patients) at a single centre using the Mobility Total Ankle Replacement. At final review, six patients had died and five ankles (5%) had been revised, two by fusion and three by exchange of components. All remaining patients were reviewed at a minimum of three years. The mean follow-up was 43 months (4 to 63). The three-year survival was 97% (95% confidence interval (CI) 91 to 99). The four-year survival was 93.6% (95% CI 84.7 to 97.4). The portion of bony interface that was visible on plain radiograph was divided into 15 zones and a radiolucent line or osteolytic cavity was seen in one zone in 14 ankles. It was not seen in more than one zone. In five ankles it was >
10 mm in width. This study suggests that the early outcome of ankle replacement is comparable to that of other total joint replacements.
Between 2002 and 2008, 130 consecutive ankles were replaced with an hydroxyapatite (HA) and titanium-HA-coated Ankle Evolutive System total ankle prosthesis. Plain radiographs were analysed by two independent observers. Osteolytic lesions were classified by their size and location, with cavities >
10 mm in diameter considered to be ‘marked’. CT scanning was undertaken in all patients with marked osteolysis seen on the plain radiographs. Osteolytic lesions were seen on the plain films in 48 (37%) and marked lesions in 27 (21%) ankles. The risk for osteolysis was found to be 3.1 (95% confidence interval 1.6 to 5.9) times higher with implants with Ti-HA porous coating. Care should be taken with ankle arthroplasty until more is known about the reasons for these severe osteolyses.
