Incidence of soft tissue releases in robotic assisted cementless TKA with mechanical alignment and flexion gap balancing

Abstract

Background To ensure the success of total knee arthroplasty (TKA), precise bone cuts and a well-balanced soft tissue envelope are crucial. Soft tissue release may be necessary, subject to various factors. Therefore, documenting the type, frequency, and necessity of soft tissue releases can establish a benchmark for comparing different alignment techniques and philosophies and evaluating their outcomes. The purpose of this study was to demonstrate that robotic-assisted knee surgery requires minimal soft tissue release. Methods We prospectively documented and retrospectively reviewed the soft tissue releases employed in securing ligament balance in the first 175 patients who received robotic-assisted TKAs at Nepean Hospital. ROSA was utilized in all surgeries with the aim of restoring mechanical coronal alignment, with a flexion gap balancing technique. Surgeries were performed between December 2019 to August 2021 by a single surgeon who used a standard medial parapatellar approach without a tourniquet, and the cementless persona prosthesis. All patients were followed up for a minimum of 6 months post-surgery. Soft tissue releases included any form of medial release for varus knee, posterolateral release for valgus knee and PCL fenestration or sacrifice. Results There were 131 female and 44 male patients, aged between 48 to 89 years (average 60 years). The preoperative HKA ranged from 22 degrees varus to 28 degrees valgus, with 71% of patients presenting with a varus deformity. For the whole group, the no need for soft tissue release was documented in 123 patients (70.3%), small fenestrated releases of PCL in 27 (15.4%), sacrifice of PCL in 8 (4.5%), medial releases in 4 (2.3%) and posterolateral releases in 13 (7.4%). In 29.7% of patients in whom a soft tissue release was necessary for balance, over half were/received minor fenestrations of the PCL. Outcomes to date included no revisions or impending revisions, 2 MUAs (1%), and Oxford knee scores averaged 40 at 6 months. Conclusion We concluded that Robot technology enhanced the precision of bone cuts and allowed for titration of required soft tissue releases to achieve optimal balance.

Is 80% satisfaction still the expectation in modern TKA mechanically aligned with robot assist? We think not

“…In our study, over 70% of patients did not require a soft tissue release as we previously reported for this group [ 16 ] and our analysis did not show any significant difference in patients’ happiness whether they required a soft tissue release or not. Abhari et al [ 17 ] reported at 1 year follow up that 93% were satisfied in the kinematic alignment group compared to 83% in the mechanical aligned group using conventional instruments [ 17 ].…”

Impact of change in coronal plane alignment of knee (CPAK) classification on outcomes of robotic-assisted TKA

“…Song et al [ 22 ] concluded that RA-TKA leads to significantly less number of outliers in terms of postoperative limb alignment when compared with conventional instruments. Selvanathan et al [ 23 ], in a prospective study with 175 patients, concluded that robot assistance enhances bone cut precision in TKA, which allows titration of soft tissue balance to achieve optimal balance. Interestingly, multiple studies have reported only 80% satisfaction rate with TKA [ 3 , 4 ].…”

Initial Learning Curve for Robot-Assisted Total Knee Arthroplasty in a Dedicated Orthopedics Center

“…In their study, Weber et al reached similar conclusions as they performed manual TKAs in an average of 77.3 min, while navigated TKAs took slightly longer, with an average of 84.1 min [37]. The similar operative times can be attributed to the fact that while RA-TKAs require some preparation, this can be performed concurrently with the surgical approach of the knee; moreover, while RA-TKA involves a series of specific steps such as pin placement, knee soft tissue evaluation, and bone reference acquisition and balancing, which are distinct from those performed during manual TKA, some surgical steps are not required, such as drilling the femoral canal or setting up an extra/intramedullary tibial guide [38][39][40]. Therefore, it is reasonable to obtain an overall similar operative time between the two methods.…”