Sagittal tibiotalar translation and clinical outcomes in mobile and fixed-bearing total ankle replacement.

BACKGROUND: Sagittal implant malalignment after total ankle replacement (TAR) has been considered to be a possible cause for premature implant failure. In a prior study, the change over time of the tibiotalar ratio (T-T ratio), which is the ratio between the posterior longitudinal talar length and the full longitudinal talar length, was assessed in 66 TARs where an unconstrained, mobile-bearing implant was implanted. The analysis documented an increase in the T-T ratio between 2 and 6 months post-surgery (on average from 34.6% to 37.2%). We hypothesized that this change might have been related to the presence of a mobile-bearing insert. In order to test our hypothesis, we designed a study to compare the translation of the talus in TARs performed with an unconstrained, mobile-bearing implant (designated the "Mobile ankle") and those performed with a semi-constrained, fixed-bearing implant (designated the "Fixed ankle"). METHODS: The study included 71 consecutive patients (71 ankles) who underwent TAR with the Mobile ankle and 24 consecutive patients (24 ankles) who received the Fixed ankle from May 2011 to December 2014. Patients were assessed clinically and radiologically preoperatively (T0), at 6 months (T2) and 12 months (T3) post-surgery. There was also a radiological assessment at 2 months post-surgery (T1). RESULTS: The comparison of the T-T ratio between the two implant groups and over time indicated an interaction between time and group, therefore the changes of the T-T ratio over time were affected by the implant type factor (P<0.001). The changes of the postoperative T-T ratio over time were not significant in the Fixed ankle group (35.7±6.7% at T1, T2, and T3; P=1.0 for each pairwise comparison). In the Mobile ankle group, the T-T ratio at 2 months (34.4±5.5%) was significantly different to the T-T ratio at 6 months (37.0±5.8%; P<0.001; i.e. there was a significant posterior translation of the talus). The AOFAS score increased from preop to 12 months post-surgery in both the Mobile ankle (72.7±12.8 at 12 months; P<0.001) and the Fixed ankle (85.0±9.7 at 12 months; P<0.001). CONCLUSION: The significant posterior translation of the talus from 2 to 6 months documented only in the Mobile ankle group may have been associated with the presence of the mobile bearing interface.

Long-term follow-up of primary total hip arthroplasty with the Alloclassic Variall system.

PURPOSE: The aim of the present study was to evaluate the clinical and radiographic results of primary total hip arthroplasty (THA) performed with the Alloclassic Variall system (a modified version of the Alloclassic Zweymüller system) and to compare them with those in the literature for the original system. METHODS: Between January 2001 and December 2002, 273 consecutive primary THAs were performed in 259 patients at a single centre with the study system, using ceramic-on-ceramic (81.7 %) or ceramic-on-highly-crosslinked-polyethylene (18.3 %) articulations. RESULTS: At the time of this study, 28 patients (29 hips; 10.6 %) had died and 40 (43 hips; 15.8 %) were lost to follow-up. Seventeen patients (19 hips; 7.0 %) could be reached only by telephone. There were four revisions in four patients (1.5 %), all involving only the femoral component. Ten-year Kaplan-Meier survival with revision of any component for any reason as the endpoint was 98.4 % (95 % confidence interval: 96.9-100 %; 30 hips remained 'at risk'). A total of 170 unrevised patients (178 hips; 65.2 %) were assessed clinically and radiographically at a median follow-up of 9.3 years (interquartile range [IQR] 8.8-9.8 years). The median Harris hip score (HHS) was 99.9 points (IQR 97.7-100). The score did not differ significantly between the two articulations. There was no sign of radiographic loosening. CONCLUSIONS: The ten-year implant survival and the HHS score outcomes for THAs performed with the novel system were in line with those documented in the literature for its predecessor.

Ten-Year Results of Primary and Revision Condylar-Constrained Total Knee Arthroplasty in Patients with Severe Coronal Plane Instability.

OBJECTIVE: To retrospectively review the results at minimum ten years after surgery of a consecutive series of total knee arthroplasties (TKAs) performed using a constrained condylar implant in patients with severe coronal plane instability. MATERIALS AND METHODS: The series comprised of 44 patients (45 knees) who received primary (19 knees) or revision (26 knees) TKA with a constrained condylar implant between 2001 and 2003 at a single institution. RESULTS: There were no revisions or any other surgery related complications at a mean implantation time of 11.0 years. In 38 patients (15 knees in the primary group and 24 knees in the revision group) who were available for clinico-radiographic follow-up at a minimum of ten years, there was no sign of radiographic loosening. Two patients showed cortical hypertrophy at the extension stem tip but none complained of pain around the stem tip. According to the TLKSS score grading, 73% of the patients in the primary group had results categorized as good or excellent, while 54% of the patients in the revision group had fair results. Four patients (one (7%) in the primary group and three (13%) in the revision group) had poor results. The median WOMAC Index was 80.2% (interquartile range: 74.0% - 81.2%) and 74.0% (interquartile range: 72.1% - 75.8%) in the primary and in the revision groups, respectively (p=0.010). CONCLUSION: This study showed satisfactory clinical outcomes with no re-operations at minimum ten years after implantation in patients who had undergone primary or revision TKA with a condylar constrained implant.