Improved clinical outcomes when maintaining a neutral joint line obliquity at high tibial osteotomy and subsequent total knee arthroplasty

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: < 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.