Alexander D Orsi1, Edgar A Wakelin2, Christopher Plaskos2, Josh Petterwood3, Simon Coffey4. 1. Corin Ltd, Clinical Research, 480 Paramount Drive, Raynham, MA, 02767, USA. alex.orsi@coringroup.com. 2. Corin Ltd, Clinical Research, 480 Paramount Drive, Raynham, MA, 02767, USA. 3. Department of Surgery, Royal Hobart Hospital, Hobart, TAS, 7000, Australia. 4. Department of Orthopaedics, Nepean Hospital, Penrith, NSW, 2750, Australia.
Abstract
PURPOSE: The purpose of this study was to compare ligament balance and laxity profiles achieved throughout flexion in restricted kinematic alignment (rKA) and gap balancing (GB). rKA and GB both aim to improve soft tissue balance and reduce ligament releases in total knee arthroplasty (TKA). METHODS: One surgeon performed 68 rKA, another performed 73 GB TKAs using the same CR implant and robotic system. rKA limited femoral valgus and tibial varus to 6°, with tibial recuts performed to achieve balance. GB limited tibial varus and femoral valgus to 2°, with femoral resections adjusted to achieve mediolateral balance throughout flexion using predictive-gap planning software. Final joint laxity was measured using a robotic ligament tensioner. Statistical analyses were performed to compare differences in mediolateral balance and joint laxity throughout flexion. Further analyses compared alignment, joint line elevation and orientation (JLO), and frequency of ligament releases and bone recuts. RESULTS: Both techniques reported greater lateral laxity throughout flexion, with GB reporting improved mediolateral balance from 10° to 45° flexion. GB resected 1.7 mm more distal femur (p ≤ 0.001) and had greater overall laxity than rKA throughout flexion (p ≤ 0.01). rKA increased JLO by 2.5° and 3° on the femur and tibia (p ≤ 0.001). Pre-operative and post-operative coronal alignment were similar across both techniques. rKA had a higher tibial recut rate: 26.5% vs 1.4%, p < 0.001. CONCLUSIONS: rKA and GB both report lateral laxity but with different JLO and elevation. Use of a predictive-gap GB workflow resulted in greater mediolateral gap symmetry with fewer recuts. LEVEL OF EVIDENCE: III, retrospective cohort study.
PURPOSE: The purpose of this study was to compare ligament balance and laxity profiles achieved throughout flexion in restricted kinematic alignment (rKA) and gap balancing (GB). rKA and GB both aim to improve soft tissue balance and reduce ligament releases in total knee arthroplasty (TKA). METHODS: One surgeon performed 68 rKA, another performed 73 GB TKAs using the same CR implant and robotic system. rKA limited femoral valgus and tibial varus to 6°, with tibial recuts performed to achieve balance. GB limited tibial varus and femoral valgus to 2°, with femoral resections adjusted to achieve mediolateral balance throughout flexion using predictive-gap planning software. Final joint laxity was measured using a robotic ligament tensioner. Statistical analyses were performed to compare differences in mediolateral balance and joint laxity throughout flexion. Further analyses compared alignment, joint line elevation and orientation (JLO), and frequency of ligament releases and bone recuts. RESULTS: Both techniques reported greater lateral laxity throughout flexion, with GB reporting improved mediolateral balance from 10° to 45° flexion. GB resected 1.7 mm more distal femur (p ≤ 0.001) and had greater overall laxity than rKA throughout flexion (p ≤ 0.01). rKA increased JLO by 2.5° and 3° on the femur and tibia (p ≤ 0.001). Pre-operative and post-operative coronal alignment were similar across both techniques. rKA had a higher tibial recut rate: 26.5% vs 1.4%, p < 0.001. CONCLUSIONS: rKA and GB both report lateral laxity but with different JLO and elevation. Use of a predictive-gap GB workflow resulted in greater mediolateral gap symmetry with fewer recuts. LEVEL OF EVIDENCE: III, retrospective cohort study.
Authors: Ephrat Most; Guoan Li; Steven Schule; Peter Sultan; Sang Eun Park; Shay Zayontz; Harry E Rubash Journal: Clin Orthop Relat Res Date: 2003-11 Impact factor: 4.176
Authors: John M Keggi; Edgar A Wakelin; Jan A Koenig; Jeffrey M Lawrence; Amber L Randall; Corey E Ponder; Jeffrey H DeClaire; Sami Shalhoub; Stephen Lyman; Christopher Plaskos Journal: Arch Orthop Trauma Surg Date: 2021-07-13 Impact factor: 3.067
Authors: Edgar A Wakelin; Sami Shalhoub; Jeffrey M Lawrence; John M Keggi; Jeffrey H DeClaire; Amber L Randall; Corey E Ponder; Jan A Koenig; Stephen Lyman; Christopher Plaskos Journal: Knee Surg Sports Traumatol Arthrosc Date: 2021-02-12 Impact factor: 4.342