Leg length discrepancy should be assessed based on the whole length of the lower limb in patients with osteoarthritis secondary to developmental dysplasia of the hip

Ryuichi Sato; Hidetoshi Hamada; Keisuke Uemura; Kazuma Takashima; Wataru Ando; Masaki Takao; Mitsuru Saito; Nobuhiko Sugano

doi:10.1302/2633-1462.52.BJO-2023-0152.R1

Leg length discrepancy should be assessed based on the whole length of the lower limb in patients with osteoarthritis secondary to developmental dysplasia of the hip

Bone Jt Open. 2024 Feb 1;5(2):79-86. doi: 10.1302/2633-1462.52.BJO-2023-0152.R1.

Authors

Ryuichi Sato^{1

2}, Hidetoshi Hamada¹, Keisuke Uemura³, Kazuma Takashima³, Wataru Ando¹, Masaki Takao³, Mitsuru Saito², Nobuhiko Sugano¹

Affiliations

¹ Department of Orthopaedic Medical Engineering, Osaka University Graduate School of Medicine, Suita, Japan.
² Department of Orthopaedic Surgery, The Jikei University School of Medicine, Tokyo, Japan.
³ Department of Orthopaedic Surgery, Osaka University Graduate School of Medicine, Suita, Japan.

PMID: 38295838
PMCID: PMC10830171
DOI: 10.1302/2633-1462.52.BJO-2023-0152.R1

Abstract

Aims: This study aimed to investigate the incidence of ≥ 5 mm asymmetry in lower and whole leg lengths (LLs) in patients with unilateral osteoarthritis (OA) secondary to developmental dysplasia of the hip (DDH-OA) and primary hip osteoarthritis (PHOA), and the relationship between lower and whole LL asymmetries and femoral length asymmetry.

Methods: In total, 116 patients who underwent unilateral total hip arthroplasty were included in this study. Of these, 93 had DDH-OA and 23 had PHOA. Patients with DDH-OA were categorized into three groups: Crowe grade I, II/III, and IV. Anatomical femoral length, femoral length greater trochanter (GT), femoral length lesser trochanter (LT), tibial length, foot height, lower LL, and whole LL were evaluated using preoperative CT data of the whole leg in the supine position. Asymmetry was evaluated in the Crowe I, II/III, IV, and PHOA groups.

Results: The incidences of whole and lower LL asymmetries were 40%, 62.5%, 66.7%, and 26.1%, and 21.7%, 20.8%, 55.6%, and 8.7% in the Crowe I, II/III, and IV, and PHOA groups, respectively. The incidence of tibial length asymmetry was significantly higher in the Crowe IV group (44.4%) than that in the PHOA group (4.4%). In all, 50% of patients with DDH-OA with femoral length GT and LT asymmetries had lower LL asymmetry, and 75% had whole LL asymmetry. The incidences of lower and whole LL asymmetries were 20% and 42.9%, respectively, even in the absence of femoral length GT and LT asymmetries.

Conclusion: Overall, 43% of patients with unilateral DDH-OA without femoral length asymmetry had whole LL asymmetry of ≥ 5 mm. Thus, both the femur length and whole LL should be measured to accurately assess LL discrepancy in patients with unilateral DDH-OA.