Abstract

Cemented total hip arthroplasty (THA) in the younger patient has historically been associated with higher wear and revision rates. We carried out a retrospective study of a prospectively collected database of patients at Wrightington hospital undergoing cemented THA under 55 years of age to determine acetabular wear and revision rates.

Between August 2005 and December 2021 a cohort of 110 patients, 56 males and 54 females, underwent Cemented Total Hip Replacement through a posterior approach. Mean age at operation was 50yrs (35–55). The mean follow up was 6 years 9 months (0–16 years). 3 patients were lost to follow-up. Of the remaining 107 patients, Conventional and cross lined polyethylene were used in 54 and 53 patients respectively. Ceramic heads were used in 102 patients. 22.225mm and 28mm heads were used in 60 and 47 patients respectively. Clinical outcomes were assessed by Merle d'Aubigne and Postel scores which showed significant functional improvement. Linear wear was measured on plain radiographs using TRAUMA CAD and cup loosening was assessed by classification of Hodgkinson et al.

No cases were revised during the observed follow up period. The mean wear rate in conventional and crosslinked polyethylene cups were 2.31mm (0.1–4.6) and 1.02mm (0.1–2.6) respectively.

Cemented THA with both conventional and crosslinked polyethylene provides excellent survival rates in adults under the age of 55 years and crosslinked polyethylene may further improve these results due to improved wear rates.

Purpose: Femoral neck fracture collapse and shortening has been a desired effect of parallel screw fixation to promote healing. While some degree of compression might be beneficial, it remains unknown whether the effects of uncontrolled femoral neck shortening leads to detectable functional impairment. We aimed to evaluate the effect of shortening and varus collapse after cancellous screw fixation of femoral neck fractures on patient functional status and quality of life.

Method: The databases of four University Hospitals were screened to identify patients with a healed isolated femoral neck fracture. Patients were contacted by telephone to complete Short-form 36(SF36) and Euroquol-5D(EQ5D) questionnaires (Primary outcome: SF36 physical functioning score[PF]). Femoral neck shortening and varus collapse were assessed by three independent reviewers blinded to functional outcome results based on the latest follow-up radiographs and categorized into three grades: None/Mild (within 5mm/5°), Moderate (5–10mm/5–10°), and Severe (> 10mm/> 10°). The minimal clinically important difference for SF36 PF score equals 12 points (1/2 of Standard deviation).

Results: Out of 660 patients screened at all four sites 70 met the inclusion criteria and were available for follow-up. The average follow-up was 20 months and an the average age was 71 years. Overall, there were 24/70 patients with none/mild femoral neck shortening, 25/70 with moderate shortening and 21/70 with severe shortening. Patients with severe shortening of their hip had significantly lower SF36 physical functioning scores (No/Mild vs. Severe shortening: 74 vs. 42 points, p=0.01). Similar important effects occurred with moderate shortening suggesting a gradient effect (No/Mild vs. Moderate shortening: 74 vs. 53 points). Some degree of varus collapse occurred in 39% of the patients and correlated moderately with the occurrence of shortening (r=0.66, p< 0.001).

Conclusion: A large proportion of displaced and undisplaced femoral neck fractures fixed with cancellous screws heal in a shortened position (66%) and varus (39%). The differences in function we observed represent patient important declines and suggest that uncontrolled sliding with cancellous screw fixation has limitations.