Achieving coronal plane alignment in total knee arthroplasty through modified preoperative planning based on long-leg radiographs: a prospective study

Abstract

Purpose This prospective study was undertaken to examine whether the desired coronal plane alignment of limb and prosthetic components in total knee arthroplasty (TKA) could be achieved precisely using conventional jig-based methods by modifying the preoperative planning of bone resection utilizing long-leg radiographs (LLRs). Methods The study included consecutive 245 TKA procedures. Pre- and postoperative radiological variables, i.e., the mechanical axis (hip-knee-ankle [HKA] axis), mechanical lateral distal femoral angle (mLDFA), and medial proximal tibial angle (MPTA), and their outliers were evaluated. Statistical analysis was performed using SPSS version 21.0. Results The mean postoperative HKA axis, mLDFA and MPTA was 179.80 ± 1.81° (p < 0.01; 95% CI: 8.09–9.67), 90.35 ± 1.54° (p < 0.01; 95% CI: 1.33–2.02), and 90.26 ± 1.25° (p < 0.01; 95% CI: 4.41–5.20), respectively. The postoperative HKA axis on the coronal plane was 180 ± 3° in 235 knees (95.92%, 4.08% outliers). Femoral and tibial components were implanted in an acceptable position, withing 90 ± 3° of the mechanical axis of the femur and tibia on the coronal plane in 238 (97.14%, 2.86% outliers) and 243 (99.18%, 0.8% outliers) knees, respectively. Conclusion Modified preoperative planning for TKA on LLRs is a reliable and consistent method to achieve the desired limb and component alignment on the coronal plane without adding financial or logistical costs. Level of evidence II

Medial pivot design does not yield superior results compared to posterior-stabilised total knee arthroplasty: a systematic review and meta-analysis of randomised control trials

“…Any deviation from the correct implant alignment can change the knee kinematics and impact patient satisfaction and overall material survivorship [35]. The implant positioning basically depends on the preoperative plan and the surgeons’ surgical skills [18, 35]. In our study, all radiology signs examined were similar across the groups, which means that the implant positioning was not a confounding factor for the reported clinical outcomes.…”

“…Radiographic markers are paramount for assessing a TKA. Any deviation from the correct implant alignment can change the knee kinematics and impact patient satisfaction and overall material survivorship [35]. The implant positioning basically depends on the preoperative plan and the surgeons’ surgical skills [18, 35].…”

Learning curve of robot-assisted total knee arthroplasty and its effects on implant position in asian patients: a prospective study

“…Thus, failure to restore the neutral mechanical axis leads to unfavorable clinical outcomes and prosthesis failure. However, several studies have reported a considerable proportion of outliers exceeding 3° from the neutral mechanical axis in c-TKA [ 12 , 28 , 29 ]. For the distal femoral cutting procedure, the system of IM referencing has generally been adopted in c-TKA, which could be influenced by the individual anatomic factors of the femur [ 30 ].…”

Learning curve of robot-assisted total knee arthroplasty and its effects on implant position in Asian patients: A prospective study

“…Thus, failure to restore the neutral mechanical axis leads to unfavorable clinical outcomes and prosthesis failure. However, several studies have reported a considerable proportion of outliers exceeding 3° from the neutral mechanical axis in c-TKA [12,23,24]. For the distal femoral cutting procedure, the system of IM referencing has been generally adopted in c-TKA.…”