We performed a retrospective review of a consecutive
series of 178 Mobility total ankle replacements (TARs) performed
by three surgeons between January 2004 and June 2009, and analysed
radiological parameters and clinical outcomes in a subgroup of 129
patients. The mean follow-up was 4 years (2 to 6.3). A total of
ten revision procedures (5.6%) were undertaken. The mean Ankle Osteoarthritis
Scale (AOS) pain score was 17 (0 to 88) and 86% of patients were
clinically improved at follow-up. However, 18 patients (18 TARs,
14%) had a poor outcome with an AOS pain score of >
30. A worse
outcome was associated with a pre-operative diagnosis of post-traumatic degenerative
arthritis. However, no pre- or post-operative radiological parameters
were significantly associated with a poor outcome. Of the patients
with persistent pain, eight had predominantly medial-sided pain.
Thirty TARs (29%) had a radiolucency in at least one zone. The outcome of the Mobility TAR at a mean of four years is satisfactory
in >
85% of patients. However, there is a significant incidence
of persistent pain, particularly on the medial side, for which we
were unable to establish a cause. Cite this article:
Worldwide, total ankle replacement is being more frequently offered as an alternative to ankle fusion. Most reports in the literature come from single centres with surgery performed by ‘high volume’ foot and ankle surgeons. We describe the New Zealand experience with the Scandinavian Total Ankle Replacement (STAR). Fifty-two STARs in 49 patients were implanted between September 1998 and May 2005. Eleven surgeons performed between one and thirteen of the operations. Of the 49 patients five were deceased and five refused to participate in the study. The average age at surgery was 64.9 years (range 46-80). There were 26 males and 13 females. The average follow up was 58.2 months. Of the 41 ankles available for review 11 had been revised or fused (27%) at an average of 42 months post surgery. Of the remaining 30 intact ankles recent radiographs were available on all ankles. Of the retained primary ankles, the mean Oxford ankle score was 25.6. This scale has a range from 12, for an asymptomatic ankle, to 60. The mean WOMAC score was 18.9, the SF-12 PH 42 and the SF-12 MH 54. The scores were substantially worse for the group who had been revised or arthrodesed. Perioperative x-ray findings demonstrated intraoperative malleolar fracture occurred in seven patients including one with a complete saw cut transection of the medial malleolus and one who had sustained fractures of both malleoli. The tibial component was undersised in five patients and the talus oversized in at least three patients. Of the 11 revision cases, two were bearing exchanges only. Nine involved either a major revision procedure or tibiotalocalcaneal arthrodesis for subsidence of malaligned components usually in the presence of peri-implant fracture. Of the unrevised cases, the latest x-rays did not demonstrate any significant osteolysis or increased lucent lines. Five cases demonstrated subtle talar or tibial component subsidence when compared with earlier radiographs. Despite overall satisfactory outcomes in the majority of patients the perioperative complication rate and revision rate in infrequent users is concerning. There may be implant and instrumentation elements, which also contribute to these suboptimal outcomes. Level of evidence IV, retrospective review.
Worldwide, total ankle replacement is being offered more often as an alternative to ankle fusion. Most reports in the literature come from single centers with surgery performed by ‘high volume’ foot and ankle surgeons. We describe the New Zealand experience with the Scandinavian Total Ankle Replacement (STAR). Ethical approval was gained for the study. Using the national joint register we identified all STARs performed in New Zealand. Patients were contacted by mail and consented to participate in the study. We retrospectively reviewed patient notes and x-rays. Patients were asked to complete and return an Oxford Ankle Score, WOMAC score, and SF-12. Fifty two STARs were implanted in 49 patients between 1998 and 2005. Eleven surgeons performed between one and 13 operations. Forty one STARs in 39 patients were available for follow-up at an average of 58 months. Eight STARs had been revised (19.5%) at an average of 22 months post surgery. In patients with the implant still in-situ the average oxford score was 24.9, WOMACs core 17.3, SF-12 physical component 44.1, and SF-12 mental component 54. X-rays were available for review in 30 ankles. Most components were implanted in a good position. Intra-operative malleolar fracture was noted in six ankles. The tibial component was undersized in 5 patients and the talar component was oversized in three patients. Two cases of talar subsidence and 3 cases of tibial subsidence (one requiring revision) were noted on follow-up x-rays. In New Zealand, the Scandinavian Total Ankle Replacement has a high revision rate at five years’ post surgery. A significant number of intra-operative malleolar fractures and component mal-sizing was noted. Patients who have not required revision mostly report acceptable ankle specific, and quality of life outcomes.
The Morscher Cup is an acetabular component that was popular in the Bay of Plenty Region in the early 1990’s. It is an implant for which there are limited follow up results published in the international literature. Concerns have been raised that in some centres there has been marked, ballooning acetabular bone damage or osteolysis and that the implant may be associated with a higher dislocation rate. This paper will present the 13 – 15 year follow up in patients from Tauranga. Ethical approval was gained from the Northern Region Y Ethics Committee. Patients who had had a Morscher Cup acetabular component in Tauranga from January 1992 until December 1994 were identified using the Bay of Plenty District Health Board NHI coding system and hospital logbooks. They were then invited to take part in the research which involved completion of WOMAC, Oxford hip score and SF 12 questionnaires, clinical review and an X-ray. Of 81 patients with 91 Morscher Cup acetabular components implanted during the study period 62 patients with 70 Morscher Cup acetabular components were eligible for the study. Of these, 46 patients were available for clinical review, the remainder of the patients having passed away prior to final follow up. The average age at time of surgery for patients available for final follow up was 58 years. The average length of follow up was 13.7 years. The average Oxford hip score and WOMAC were 34.8 and 17.8 respectively. The average SF-12 PH was 40.9 and the average SF-12 MH was 54.8. The Morscher Cup is an acetabular component that is still commonly used in New Zealand. The 13 –15 year results indicate that patients in this study are satisfied with their implant, but there is a lack of published data to compare them to other patient groups who have had a Morscher Cup acetabular component.
The limping or non-weight bearing child can present a difficult diagnostic dilemma. It may be possible to avoid admission of a large proportion of these patients if septic arthritis or other serious pathology can be exclude d. We have established a continuing, prospective study of all patients admitted for hip pain (with normal radiographs) to Starship Children’s’ Hospital between two and 13 years of age. Forty-two patients had a final diagnosis of transient synovitis. Only two patients during an eight month period had septic arthritis. Due to small numbers of patients with serious pathology we compared the transient synovitis group with a retrospective review of those with septic arthritis treated at Starship Hospital in the previous four years. Following comparisons of these two groups, we found that there was a greater incidence of septic arthritis in Maori and Pacific Islanders and septic arthritis tended to occur in younger children. The patients’ initial history, temperature, white cell count and ESR were sensitive in discriminating between septic arthritis and irritable hip. Once the diagnosis of “irritable hip” was made it was unlikely to be altered. We therefore would recommend that it is possible to avoid admission in a large number of these patients. We would however continue to recommend admission for those with a clear history of current illness, Maori or Pacific Islanders, children under the age of four, those with an elevated temperature, and any patient with an elevated white cell count especially neutrophil count or ESR.
