Forgotten joint score is worse when the affected leg perceived longer than shorter after total hip arthroplasty

Abstract

Background One of the causes of patient dissatisfaction after total hip arthroplasty (THA) is leg length discrepancy (LLD). Even when radiographic LLD (R-LLD) is within 5 mm, some people perceive the affected side to be longer, while others perceive it is shorter. The purpose of this study was to investigate the relationship between perceived LLD (P-LLD), R-LLD, and Forgotten Joint Score (FJS-12) after THA. Methods A retrospective study of 164 patients with unilateral hip disease was conducted. Based on P-LLD after THA, they were classified into three categories: perceived short (PS 21 patients), no LLD (PN 121 patients), and perceived long (PL 22 patients). On the other hand, based on R-LLD after THA, they were divided into < − 5 mm (RS 36 patients), − 5 mm ≤ x < 5 mm (RN 99 patients), and 5 mm ≥ (RL 29 patients), respectively. The proportion of P-LLD in the RN group was also evaluated. In each group, the relationship between P-LLD, R-LLD and FJS-12 was investigated. Results After THA, the PL group had significantly worse FJS-12 (PS: 68.3 ± 26.2, PN: 75.0 ± 20.9, PL: 47.3 ± 25.2, P < .0001). In the R-LLD evaluation, there was no difference in FJS-12 among the three groups (RS: 73.7 ± 21.1, RN: 70.0 ± 24.5, RL: 67.7 ± 25.4, P < .53). The RN group perceived leg length to be longer (RN-PL) in 12.1% of cases, and the RN-PL groups had significantly worse FJS-12 (RN-PS: 65.4 ± 24.8, RN-PN: 73.8 ± 23.1, RN-PL: 41.8 ± 27.6, P < .0001). Conclusion One year after THA, patients with longer P-LLD had worse FJS-12, even if the R-LLD was less than 5 mm.

The Sum of the Leg Length Discrepancy and the Difference in Global Femoral Offset Is Equal to That of the Contralateral Intact Side and Improves Postoperative Outcomes after Total Hip Arthroplasty: A Three-Dimensional Analysis

“…According to our findings, a GFO of 1.01 and an SGL of 0.18 mm/100 cm BH longer than that of the non-surgical side leads to improved postoperative outcomes; consequently, LLD should be adjusted slightly shorter than that of the non-surgical side. Kawakami et al [ 8 ] stated that when the perceived LLD was longer, postoperative outcomes would likely worsen, even if radiological LLDs were equal. Therefore, our findings are consistent with their results.…”

“…Finally, for LLD, we evaluated the adjusted system with the X-, Y-, and Z-axes adjusted to be parallel. Recent reports have focused on “perceived LLD [ 8 ]”, and our findings were examined as “radiological LLD”. Therefore, different findings may be observed regarding “perceived LLD”.…”

“…Leg length differences also affect hip function and postoperative outcomes, such as walking speed and stride length after THA [ 7 , 8 , 9 , 10 ]. A two-dimensional (2D) study using computed tomography (CT)-derived images previously described a relationship between the absolute value of the sum of leg length discrepancy (LLD), FO, and AO compared with the non-surgical side; a smaller absolute value of the sum may consequently be recommended to restore an absolute value of the sum; reduce the postoperative trochanteric pain syndrome; and improve the clinical outcome evaluated using the Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score, and the EuroQol of patients after THA [ 11 ].…”