No significant differences in 60-day postoperative complication rates between conventional and shortened stems

Abstract

Purpose: To compare 60-day complication rates, radiographic outcomes, and clinical outcomes following primary THA with conventional versus shortened stems, in a large cohort study.

Methods: The authors reviewed a consecutive series of 800 primary THAs, of which 781 met the inclusion/exclusion criteria: 395 received a conventional stem and 386 received a shortened stem. Intraoperative and postoperative complications were noted. Radiographic and clinical assessments were performed preoperatively and 60 days after surgery.

Results: Compared to conventional stems, shortened stems had significantly less intraoperative complications (2.8% vs 0.3%, p = 0.006), but no significant differences in complications that did not require reoperation (1.0% vs 1.3%, p = 0.620), complications that required reoperation without stem revision (2.0% vs 1.0%, p = 0.384), and complications that required stem revision (0.5% vs 0.5%, p = 1.000). Four hips (two from each group) required stem revision and were thus excluded from 60-day assessment. There were no significant differences between groups in subsidence ≥ 3 mm (1.0% vs 0.5%, p = 0.686), alignment (90.3%vs 86.7%, p = 0.192), net change in offset (within 3 mm, 32.3% vs 30.5%, p = 0.097), and limb length discrepancy (3.0 ± 2.6 mm vs 2.9 ± 2.4 mm, p = 0.695). Compared to conventional stems, shortened stems had significantly better preoperative mHHS (56.5 ± 18.5 vs 64.5 ± 13.5, p < 0.001), and significantly lower net improvement in mHHS (29.9 ± 17.1 vs 24.4 ± 15.0, p < 0.001), but no significant differences in postoperative mHHS (87.3 ± 11.9 vs 89.4 ± 9.6, p = 0.109).

Conclusions: There were no significant differences between conventional and shortened stems in terms of postoperative complication rates, radiographic outcomes, and postoperative mHHS. However, patients implanted with shortened stems had less intraoperative complications, but lower net improvement in mHHS.

Level of evidence: Level IV, Retrospective comparative cohort study.

Keywords: Radiographic outcomes; Short stems; THA; Total hip arthroplasty; Total hip replacement.

Fig. 1

Flowchart describing the initial cohort, study cohort, and final cohort

Fig. 2

Cortical thickness index (CTI) and canal calcar ratio (CCR) were performed on preoperative anteroposterior pelvic radiographs, with CTI = (d – c) / d and CCR = c / b

Fig. 3

Canal fill ratio (CFR) was calculated by dividing the femoral stem width by the endosteal diameter width at 3 levels, with the lesser trochanter (LT) as reference point: (i) 2 cm above the tip of the LT, (ii) at the level of the tip of the LT, and (iii) 7 cm below the tip of the LT