Behaviour of the ultra-short anatomic cementless femoral stem in young and elderly patients

Abstract

Purpose The question arises as to whether it is possible to obtain rigid fixation of the ultra-short metaphyseal-fitting anatomic cementless stem without diaphyseal fixation in the elderly as well as younger patients. We investigated whether ultra-short, metaphyseal-fitting anatomic cementless femoral stem would provide similar functional improvements in the younger and elderly patients, radiographically secure implant fixation would be achieved in both groups, the bone content would be preserved in both groups, and complication rates would be similar in both groups. Methods A total of 100 patients (114 hips) in the younger patient group and 100 patients (112 hips) in the elderly patient group were included in the study. Their mean age was 43.9± 6.11 years (range, 31-65 years) in the younger patient group and 78.9±12.1 years (range, 66-91 years) in the elderly patient group. The mean duration of follow-up was 7.5 years (range, six to nine years) in the younger patient group and 7.6 years (range, six to nine years) in the elderly patient group. Results The mean postoperative Harris hip scores (95 points versus 91 points), WOMAC scores (11 points versus 15 points), thigh pain (none in either group), UCLA activity scores (6.5 points versus 4.5 points), and radiographic results were not significantly different between the two groups. No hip in either group had an aseptic loosening. No hip in either group had clicking or squeaking sounds or ceramic fractures. Conclusion The cementless ultra-short, metaphyseal-fitting anatomic cementless femoral component provides stable fixation without any need of diaphyseal fixation in both younger and elderly patients. Despite the concern, the poor bone quality in elderly patients did not compromise the stability, and osseointegration of this ultra-short, anatomic cementless femoral stem was achieved in all elderly patients.

Ultrashort versus Conventional Anatomic Cementless Femoral Stems in the Same Patients Younger Than 55 Years

“…There are few short-term studies of the ultrashort stem [17,19,21,22,34], and to our knowledge well-designed randomized controlled long-term studies regarding the performance of ultrashort and conventional stems in the same patients have not been published. We therefore sought to compare ultrashort and conventional anatomic cementless stems in the same patients to document the long-term performance of both stems.…”

“…The intraobserver error in all the radiographic measurements ranged from 0.95 to 1.00 by the chance-corrected kappa coefficient [25], indicating excellent reproducibility. BMD was determined using dualenergy X-ray absorptiometry (DEXA) as reported by Kim et al [16,17,[19][20][21][22]. DEXA scans were taken at 1 week, 1 year, 10 years, and at the final followup after surgery (mean, 11.8 years).…”

“…To analyze complication rates and the radiologic data, the chi-square test with Yate's correction was used. BMD was compared using a two-tailed Student's t-test [21].…”

“…Because clinical and radiographic performance of this ultrashort anatomic cementless stem have been investigated in only a few studies and at short-term followup [16,17,19,[21][22][23]34], it remains to be determined whether an ultrashort anatomic cementless stem shows similar clinical and radiographic results, bone mineral density (BMD), and revision rate as a conventional cementless stem at long-term followup.…”

“…Thus, the distal fixation achieved with a conventional cementless stem may provide greater resistance to torsional loads [29]. Questions regarding whether an ultrashort stem will be sufficiently biomechanically stable to achieve durable bone ingrowth and longer-term clinical performance have been raised [17,21,22,34].…”