The Effects of Rasp Oversize on the Clinical and Radiographic Outcomes of Total Hip Arthroplasty With a Collared Satin-Finished Composite Beam Cemented Stem

概要

〔Purpose]
This study aimed to compare the clinical and radiographic outcomes of using two different oversized rasps in total hip arthroplasty (THA) with a composite beam cemented stem (DCM,J).

(Methods]
A consecutive series of 105 hips underwent hybrid THA using the DCM-J stem between 2006 and 2010. Among the patients with a minimum 10-year follow-up, a Hmm oversized rasp was used in 38 hips (group S), whereas a 0. 5-mm oversized rasp was used in 36 hips (group M). The Japanese Orthopedic Association hip score and radiographic findings were evaluated, including cement mantle thickness, stress shielding, and cortical hypertrophy.

[Results)
The Japanese Orthopedic Association hip score was significantly improved postoperatively with 100% of the implant survival rate in both groups when septic loosening was excluded, Radiographic assessment performed immediately postoperatively revealed that the cement mantle thickness was significantly larger in group M than group S in Gruen zone 1 but did not differ between groups in zones 2-7. Stress shielding was significantly more frequent in group M than group S at 2 years (P =・011), 5 years (P = . 012), and ≥10 years postoperatively (P = .038), Cortical hypertrophy appeared in a time-dependent manner； however, the prevalence did not significantly differ between groups at final follow'up at a mean of 11.7 years (range 10-14 years) postoperatively.

(Conclusion]
The DCM-J stem achieved good clinical results in both groups. Stress shielding was significantly more frequent in T11A using the 0. 5-mm rasp than the 1.5-nira rasp, indicating that sufficient cement mantle room should be prepared for the cemented stem.