A comparative meta-analysis of stress shielding between short-stem and conventional femoral stem in total hip...

Stress shielding-related complications remain a key clinical challenge in total hip arthroplasty (THA). While short-stem prostheses have shown potential bone-preserving benefits in preclinical and single-center studies, pooled high-quality evidence remains inconsistent. This study aimed to compare periprosthetic bone mineral density (BMD) changes between short-stem and conventional straight-stem THA, and evaluate the stress-shielding benefits of short-stem designs.

We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library from database inception to 31 March 2026 for eligible randomized controlled trials (RCTs). Meta-analysis was performed using standardized mean differences with 95% confidence intervals. Two reviewers independently assessed study quality via the GRADE criteria, and a minimum clinically important difference framework was applied to interpret BMD changes.

Six RCTs were included, involving 398 patients (202 hips with short-stem THA, 225 with conventional THA). Within 12 months postoperatively, short-stem THA showed significantly better BMD preservation in Gruen zone 1 at 3 (SMD = 0.22, P = 0.04), 6 (SMD = 0.51, P = 0.02) and 12 months (SMD = 0.59, P = 0.002), and in Gruen zone 7 at 6 months (SMD = 0.65, P < 0.00001). Subgroup analysis confirmed significant BMD preservation benefits with novel-design short stems (12-month Gruen zone 1: SMD = 0.94, P < 0.00001), while traditional tapered short stems showed no significant difference from conventional stems. No between-group differences were found in other Gruen zones.

This meta-analysis provides moderate-quality evidence that novel-design short-stem THA is associated with better short-term proximal femoral BMD preservation compared with conventional stems within 1 year postoperatively, with benefits highly specific to prosthesis design subtypes. It must be emphasized that periprosthetic BMD is a surrogate endpoint, and the observed short-term bone preservation advantage has not yet been definitively linked to reduced revision rates or decreased aseptic loosening in large-scale registry data. Stress shielding is a chronic, ongoing process, and the clinical implications of BMD differences measured at 12 months require validation through long-term follow-up studies. Clinical decision-making should be individualized, and further large-sample, long-term RCTs are needed to determine whether the observed BMD benefits translate into improved hard clinical outcomes.

PROSPERO registration number: CRD420250653026.