The association of leg length and offset reconstruction after total hip arthroplasty with clinical outcomes

• Published in: Clinical biomechanics (Bristol) Vol. 68; pp. 89 - 95
• Main Authors: Bolink, Stijn A.A.N., Lenguerrand, Erik, Brunton, Luke R., Hinds, Nicole, Wylde, Vikki, Heyligers, Ide C., Blom, Ashley W., Whitehouse, Michael R., Grimm, Bernd
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-08-2019
• Subjects: Aged; Arthroplasty, Replacement, Hip; Female; Femur - diagnostic imaging; Femur - surgery; Gait; Gait analysis; Hip - diagnostic imaging; Hip Prosthesis; Humans; Leg length; Leg Length Inequality - diagnostic imaging; Leg Length Inequality - surgery; Male; Middle Aged; Offset; Patient Reported Outcome Measures; Pelvis - diagnostic imaging; Pelvis - surgery; Postoperative Period; Prospective Studies; Reconstructive Surgical Procedures; Reproducibility of Results; Severity of Illness Index; Total hip arthroplasty; Treatment Outcome; Trendelenburg test; United Kingdom; United Kingdom; Trendelenburg test; Leg length; Patient-reported outcome measures; Total hip arthroplasty; Gait analysis; Offset
• ISSN: 0268-0033; 1879-1271
• DOI: 10.1016/j.clinbiomech.2019.05.015

Restoring native hip anatomy and biomechanics is important to create a well-functioning hip arthroplasty. This study investigated the association of hip offset and leg length after hip arthroplasty with clinical outcomes, including patient reported outcome measures, the Trendelenburg Test and gait analysis.
In 77 patients undergoing primary hip arthroplasty for osteoarthritis (age mean = 65 SD = 11 years; BMI mean = 27 SD = 5 kg/m2), hip offset and leg length discrepancy were measured on anteroposterior radiographs. The Western Ontario & McMaster Universities Osteoarthritis Index, the Trendelenburg Test and gait were assessed preoperatively, and at 3 and 12 months postoperatively. An inertial measurement unit was used to derive biomechanical parameters, including spatiotemporal gait parameters and tilt angles of the pelvis. Relationships between radiographic and functional outcomes were investigated, and subgroups of patients with >15% decreased and increased femoral offset were analysed separately.
Patient-reported function scores and clinical tests demonstrated a few significant, weak correlations with radiographic outcomes (Spearman's ρ range = 0.26–0.32; p < 0.05). Undercorrection of femoral offset was associated with lower patient-reported function scores and with more step irregularity as well as step asymmetry during gait. Postoperative leg length inequality was associated with increased frontal plane tilt angle of the pelvis during the Trendelenburg Test and increased sagittal plane motion of the pelvis during gait. Femoral offset subgroups demonstrated no significant differences for patient-reported function scores and outcomes of the Trendelenburg Test and gait analysis.
Reduced hip offset and leg length discrepancy following hip arthroplasty seem to be marginally associated with worse clinical outcomes.
•Reduced offset after total hip arthroplasty results in worse patient-reported function.•Reduced offset following total hip arthroplasty causes gait irregularity and asymmetry.•Reduced offset following total hip arthroplasty alters outcomes the Trendelenburg Test.•Leg length discrepancy below 1 cm after total hip arthroplasty does not cause impaired function.