JOA - 2026-05-22 - Journal Article
Can Arthroplasty Stem Influence Outcome (CASINO): A Seven-Year Follow-Up of a Randomized Controlled Trial of Stem Length in Cemented Total Hip Arthroplasty.
Clement ND, Williamson TR, Chopra S, Ohly NE, Macpherson GJ, Gaston P
Topics
Key Takeaway
At 7.3-year median follow-up, 125mm and 150mm cemented polished taper slip stems showed equivalent Oxford Hip Scores (mean difference 0.5, 95% CI -2.1 to 4.4) and equivalent survival (98.1% vs 98.2%), but the short stem demonstrated 0.7mm less subsidence.
Summary Depth
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Summary
This multicenter double-blind RCT compared a 125mm short versus 150mm standard cemented polished taper slip stem in 220 THA patients, assessing Oxford Hip Score, HRQoL, satisfaction, and radiographic survival through 7 years. No significant differences were found in Oxford Hip Score, Forgotten Joint Score, EQ-5D, EQ-VAS, SF-12, or satisfaction at any time point. Survival was equivalent at 98.1% vs 98.2%; however, the standard stem showed significantly greater subsidence (mean 0.7mm, P=0.035) and the short stem produced medial cortical femoral hypertrophy in 3 patients.
Key Limitation
Attrition to only 116 patients (53%) at 5-year follow-up compromises statistical power to detect clinically meaningful divergence in outcomes at mid-term, particularly for survival analysis.
Original Abstract
BACKGROUND
To assess whether a cemented short (125 mm) polished taper slip (PTS) stem offered an equivalent hip-specific outcome, health-related quality of life (HRQoL), satisfaction, and survival compared to the standard (150 mm) stem when used for total hip arthroplasty (THA).
METHODS
A multicenter double-blind randomized controlled trial was conducted. There were 220 patients randomized to either a standard or a short stem. Patient-reported outcome measures were completed preoperatively and at one (n = 193), two (n = 180), five (n = 116), and seven (n = 148) years postoperatively. Radiographic assessment was undertaken postoperatively, at one year (n = 210) and at a median follow-up of six years (n = 188).
RESULTS
There were no significant (P ≥ 0.428) differences in hip-specific function between the groups according to the Oxford hip score at any time point, with a marginal mean difference of 0.5 (95% confidence interval [CI] -2.1 to 4.4, P = 0.681) over the postoperative period (primary outcome). A similar trend was also observed for the forgotten joint score, EQ-5D, EQ-VAS, and short-form 12, with no significant (P ≥ 0.083) differences between the groups at any postoperative assessment or in the mean difference over the follow-up period (P ≥ 0.550). There were no differences in satisfaction at one (P = 0.537), two (P = 0.777), five (P = 0.438), or seven years postoperatively (P = 0.999). A greater subsidence (mean 0.7 mm, 95% CI 0.1 to 1.3, P = 0.035) was observed for the standard stem at a median of six years. There were three short-stem patients who demonstrated medial cortical femoral hypertrophy. The survival rate of the standard stem was 98.2% (95% CI 95.7 to 100) and 98.1% (95% CI 95.6 to 100) for the short stem at a median follow-up of 7.3 years, which was not significantly different (P = 0.994).
CONCLUSION
The short PTS stem had equivalent hip-specific outcomes, HRQoL, patient satisfaction, and survival when compared to the standard stem at seven years following THA, but was associated with reduced subsidence and proximal femoral hypertrophy.