Abstract Purpose The primary aim was to study the impact of joint line obliquity (JLO) on clinical outcomes and survivorship in patients undergoing total knee arthroplasty (TKA) after a previous high tibial osteotomy (HTO). The secondary aim was to study how maintaining neutral JLO at both HTO and TKA affected clinical outcomes of TKA. Methods A retrospective review of patients undergoing TKA following valgus‐producing HTO, having a minimum 1‐year follow‐up, was performed. Using the coronal plane alignment of the knee (CPAK) classification, three groups of JLO were formed: distal JLO (183°). Clinical outcomes were assessed using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC). The level of significance was 0.05. Results The study included 110 TKA (mean follow‐up: 5.8 years). Prevalence of a proximal JLO post‐TKA was higher ( p 0.05). Post‐TKA, the stiffness, function and total WOMAC were significantly better ( p < 0.05) in patients with a neutral JLO pre‐TKA and neutral JLO post‐TKA as compared to those with a proximal JLO pre‐TKA and proximal JLO post‐TKA or a proximal JLO pre‐TKA and neutral JLO post‐TKA. Conclusion While a proximal JLO after conversion TKA did not show a statistically higher revision rate, maintaining a neutral JLO during HTO and at the time of subsequent TKA was associated with higher post‐operative clinical scores. However, further research in different and larger populations is needed to confirm these findings. Level of Evidence Level IV.
Maniar et al. (Thu,) studied this question.