Primary Total Hip Arthroplasty in Patients 20 Years Old and Younger.

Background: Historically, total hip arthroplasty (THA) performed in patients ≤20 years old has been associated with poor survivorship because of bearing-surface wear with conventional polyethylene, acetabular loosening with cemented sockets, and liner fracture in ceramic-on-ceramic (CoC) THA. For this population, there is a paucity of data regarding outcomes of THAs performed with use of modern implants and bearing surfaces. The purpose of the present study was to examine the mid- to long-term outcomes of modern THA in patients ≤20 years old.

Methods: Utilizing a single-institution, prospectively collected total joint registry, we retrospectively identified 91 primary THAs performed in 78 patients ≤20 years old from 1998 to 2016. The average patient age was 17 years (range, 11 to 20 years), and the average body mass index was 26 kg/m (range, 16 to 49 kg/m). Forty-eight THAs (53%) were performed in male patients, and 47 (52%) were performed on the right hip. Bearing surfaces included CoC (53 THAs, 58%), metal-on-highly cross-linked polyethylene (MoP; 28 THAs, 31%), and ceramic-on-highly cross-linked polyethylene (CoP; 10 THAs, 11%). Outcome measures included reoperations, revisions, complications, clinical outcome scores, and bearing-surface wear.

Results: At an average follow-up of 8 years (range, 2 to 18 years), the average modified Harris hip score was 92 (range, 54 to 100), and 95% of patients reported feeling "much better" following the surgical procedure. Survivorship at 2, 5, and 10 years postoperatively was 96.7%, 96.7%, and 95.0% for reoperation; 98.9%, 98.9%, and 97.2% for revision; and 91.2%, 91.2%, and 89.5% for complications, respectively. The most common complications were instability (3 THAs, 3%), aseptic acetabular loosening (2 THAs, 2%), and postoperative foot drop (2 THAs, 2%). Linear articular wear averaged 0.019 mm/yr. There were no correlations between age, sex, body mass index, bearing surface, femoral head size, use of cement, or operative time and survivorship from complications, reoperations, or revisions. There were no differences in linear wear among CoC, CoP, and MoP bearing surfaces.

Conclusions: In patients ≤20 years old, THAs performed with use of modern implants exhibit excellent clinical outcome scores and survivorship at mid- to long-term follow-up. CoC, CoP, and MoP bearing surfaces have similar survivorship, clinical outcomes, and bearing-surface wear in this population.

Level Of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.