Arthrofibrosis in Robotic Total Knee Arthroplasty: An Investigation Into How Robotic Assistance May Contribute to a Tight Knee.

INTRODUCTION: Arthrofibrosis after total knee arthroplasty (TKA) can lead to pain and restricted range of motion. Matching native knee kinematics is crucial in avoiding arthrofibrosis postoperatively. However, manual jig-based instruments have demonstrated variability and inaccuracy during primary TKA. Robotic-arm-assisted surgery was developed to increase the precision and accuracy of bone cuts and component alignment. In the literature, limited information on arthrofibrosis after robotic-assisted TKA (RATKA) exists. The purpose of this study was to compare the incidence of arthrofibrosis after manual TKA (mTKA) with RATKA by examining the need for manipulation under anesthesia (MUA) postoperatively and evaluating preoperative and postoperative radiographic parameters. METHODS: A retrospective analysis of patients who underwent primary TKA from 2019 to 2021 was conducted. Rates of MUA were evaluated and perioperative radiographs were analyzed to determine posterior condylar offset ratio, Insall-Salvati Index, and posterior tibial slope (PTS) in patients who underwent mTKA versus RATKA. Range of motion was recorded for patients who required MUA. RESULTS: A total of 1234 patients were included, of which 644 underwent mTKA, and 590 underwent RATKA. Thirty-seven RATKA patients compared with 12 mTKA patients required MUA postoperatively (P < 0.0001). A significant decrease in PTS postoperatively was seen in the RATKA (7.10° ± 2.4° preoperatively versus 2.46° ± 1.2° postoperatively), with a mean decrease of the tibial slope of -4.6° ± 2.5° (P < 0.0001). In patients requiring MUA, a larger decrease was seen in the RATKA group when compared with the mTKA group (mean -5.5 ± 2.0 versus -5.3 ± 0.78, P = 0.6585). No significant difference was seen in the posterior condylar offset ratio and Insall-Salvati Index in both groups. DISCUSSION: When conducting RATKA, it is important to match PTS close to the native tibial slope to decrease the incidence of arthrofibrosis postoperatively, as a decrease in PTS can lead to decreased postoperative knee flexion and poor functional outcomes.

Improving Postoperative Acute Kidney Injury Rates Following Primary Total Joint Arthroplasty.

BACKGROUND: Perioperative hip and knee arthroplasty complications remain a significant clinical and financial burden. Our institution has shifted to developing protocols to decrease these perioperative complications. This study focuses on acute kidney injury (AKI) rate status post primary total joint arthroplasty (TJA). Current literature demonstrates a 2%-15% incidence of AKI following TJA. However, there is a paucity of published literature on protocols that have effectively reduced AKI rates following TJA. The purpose of this study is to evaluate the effect that our institutionally developed perioperative renal protocol had on the postoperative AKI rates. METHODS: A retrospective cohort study was performed. Patient demographics, baseline creatinine, and postoperative creatinine values during the patient's hospitalization were collected and analyzed. The preintervention cohort data contained all patients at our institution who underwent a primary TJA from November 1, 2016 to January 1, 2018. The postintervention cohort included all primary TJA patients from July 1, 2018 to February 2, 2020. AKI was defined using the AKI Network classification system comparing baseline and postoperative creatinine values. A multivariate analysis was performed to determine the statistical significance of our results. RESULTS: Before intervention 1013 patients underwent a primary TJA with 68 patients developing an AKI postoperatively. After intervention 2169 patients underwent primary TJA with 90 patients developing an AKI (6.71% vs 4.15%; P = .0015, odds ratio = 0.59, 95% confidence interval = 0.42-0.82). CONCLUSION: This study demonstrated that implementation of a perioperative renal protocol can significantly reduce AKI rates. A reduction in AKI rates following TJA will result in improved outcomes and secondarily decrease the financial impact of postoperative complications seen following TJA.

The UniSpacer: a treatment alternative for the middle-aged patient.

The UniSpacer is a metallic tibial hemiarthroplasty for treatment of isolated osteoarthritis of the medial compartment of the joint. It is a mobile-bearing, self-centering shim that is introduced into the knee through a limited medial arthrotomy without requiring bone cuts or fixation to the tibia or femur. Clinical data are now available that define the efficacy of the procedure in addition to defining the ideal clinical setting for its use in the treatment of osteoarthritis of the medial compartment of the knee.

Unicompartmental tibial hemiarthroplasty: early results of the UniSpacer knee.

An intra-articular metallic spacer is evaluated for the treatment of isolated medial compartment OA. It is proposed that this implant can provide axial correction for a varus deformity, eliminate the pseudolaxity of the MCL, improve knee function, maintain ROM, and provide pain relief. One-and 2-year data are presented on 71 UniSpacer Knee System implants that were implanted in 67 patients (four had bilateral surgeries). The mean age and weight of these patients was 54 years and 94 kg (207 lb), respectively. The heaviest patient in the group weighed 168 kg (370 lb). All knees were evaluated using the Knee Society clinical rating system, Lysholm scoring scale, radiographic limb alignment, and ROM. The mean Knee Society knee score improved 169% in the 1-year group and 193% in the 2-year group. The mean Knee Society function score improved 31% and 65%, respectively. The mean Lysholm score improved 88% and 140%, respectively. Five implants (7%) were revised to total knee arthroplasty (TKA) and 10 implants (14%) were revised to another UniSpacer Knee System implant. The early results suggest that an intra-articular metallic spacer is a viable treatment option for OA in the younger patient.

The UniSpacer Knee System: have we been there before?

Tibial hemiarthroplasty using the UniSpacer Knee System is a viable treatment alternative for knee osteoarthritis of the medial compartment. Improvements in patient selection, surgical technique, and rehabilitation continue to improve results. In contrast to alternative procedures, implantation of the UniSpacer Knee System preserves the natural knee anatomy therefore future knee procedures are not compromised. The early results suggest that the UniSpacer Knee System is a complementary alternative to other treatment options.