Abstract
Research Type:
Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies
Introduction/Purpose:
As with other artificial joint surgeries, osteolysis in ankle artificial joint is a major cause of implant loosening. It is known that polyethylene wear particles are the main cause, but it is also caused by implant surface coating particles such as metal and hydroxyapatite (HA) particles. In particular, in the case of HA, early pattern of osteolysis is known to progress in a focal cystic shape, but there is no comparative study between HA coating and non-HA coating implants. Therefore, this study aimed to compare the postoperative osteolysis patterns between Taric system (Titanium coating) and Hintegra system (HA coating).
Methods:
Patients who underwent total ankle arthroplasty with either Taric or Hintegra at our medical center and had a follow-up period of at least 2 years were included in the study. A total of 39 patients were identified in the Taric group and 451 patients in the Hintegra group. To adjust for baseline potential confounders, a propensity score matching (PSM) analysis was performed. Matching was conducted using a 1:1 matching protocol with the nearest neighbor matching algorithm. Preoperative and postoperative clinical outcomes, including pain visual analog scale, ankle osteoarthritis scale, and ankle range of motion were compared. Radiological outcomes were assessed by evaluating the presence of osteolysis, its pattern (focal cystic or diffuse linear, Figure 1.), the volume, and the shortest time to occurrence.
Results:
Baseline patient-related characteristics were well balanced after the PSM analysis (mean follow-up 27.3 months, 24 – 54). There was no significant difference in pre- and post-operative clinical outcomes between the two groups. Regarding radiological outcomes, there was no significant difference in the overall incidence of periprosthetic osteolysis between two groups (81.6% vs. 64.1%, p = 0.125), whereas ballooning osteolysis was more common in the Hintegra group (18.4% vs. 41.0%, p = 0.046). The time to the first appearance of osteolysis was significantly shorter in the Taric group (5.3 vs. 12.6 months, p = 0.002). There was no significant difference in early osteolysis volume between the two groups (2.5 cm3 vs. 3.2 cm3, p = 0.197).
Conclusion:
The results of this study showed that focal cystic osteolysis occurred more frequently with the Hintegra system in the short-term radiological follow-up results, and in particular, its size tended to be larger compared to the metal coating implants. This phenomenon could be likely caused by the HA. Clinically, it is closely related to the loosening of the HA coating component, so continuous observation of changes is required.
Patterns of osteolysis
A. Diffuse linear, B. Focal cystic