gms | German Medical Science

Objectives: Does a new cemented all poly acetabular cup provide acceptable survivorship and patient-reported outcomes of Total Hip Arthroplasty in an elderly population?

Methods: This non-randomized prospective observational study was conducted on 72 (17 male and 55 female) patients with an average age of 72.1 years (Table 1 [Tab. 1]).

A population of this age is susceptible to having poor bone quality that puts them at risk for intra-operative fracture or other bone quality-related complications if implanted with a metal press-fit cup. The acetabular cup in this study is made of cross-linked polyethylene and features grooves to allow mechanical interlocking with bone cement. Patients receiving a primary implantation with the cemented all-polyethylene acetabular cup and either a cemented or uncemented tapered wedge femoral stem were included in the study. Adverse events and revisions were recorded. EQ-5D index scores, EQ Visual Analogue Scores (VAS), and Oxford Hip Scores (OHS) were collected during visits at early (2-5 years) and mid-term (5-7 years) follow-up. A t-test was used to determine whether the scores changed over time.

Results and conclusion: During the study, 1 patient was lost to follow-up, 2 requested discontinuation from the study, and 1 was revised for deep wound infection at 3.6 years follow-up. There were no revisions related to the design of the cup or the bone quality of the patients. Overall, the survivorship of the cup with an endpoint of revision for any reason is 98.6% at a mean follow-up of 4.04 years. This survivorship is higher than the 4-year survivorship of between 96% and 97% for elective total hip arthroplasties reported by the 2019 German Arthroplasty Registry (EPRD) Annual Report. The EQ-5D index scores recorded at early and mid-term follow-up (Table 2 [Tab. 2]) are higher than the average EQ-5D index scores for 65-74 year old patients in Germany (0.838) [1]. The EQ VAS values recorded at early and mid-term follow-up (Table 2 [Tab. 2]) are above the average EQ VAS values for 65-74 year old patients in Germany (68.6) [1]. The mean OHS values reach the benchmark for "excellent" (above 41) at both follow-ups. The OHS values met the benchmark for "good" (34 to 41) in 90% of patients at early follow-up and 85% of patients at mid-term follow-up. None of the scores were significantly different between the early and mid-term follow-ups (EQ-5D: p=0.18; EQ VAS: p=0.99; OHS: p=0.50).

The excellent clinical scores and high survivorship at mid-term associated with the acetabular cup in this study show that the new cemented all-polyethylene cup is a viable treatment option for the elderly population. The study will be continued to determine if these results can be expected at even longer follow-up periods.