Predictive factors for deep medial collateral ligament release in adjusted mechanical alignment total knee arthroplasty.

BACKGROUND: Total knee arthroplasty (TKA) demands precision in achieving optimal alignment and soft tissue balance, especially in cases of medial compartment osteoarthritis where the need for medial soft tissue release is critical yet challenging to ascertain. OBJECTIVE: This study aims to systematically investigate the relationship between preoperative data, initial knee conditions and the necessity for deep collateral ligament (MCL) release in adjusted mechanical alignment total knee arthroplasty. METHODS: We conducted a retrospective study involving 61 TKA patients who underwent adjusted mechanical alignment robotic-assisted procedures. Soft tissue release was carried out when clinically indicated. We collected and statistically analyzed patient demographics, initial knee conditions, and surgical details. RESULTS: Among the patients, 52% required deep MCL release. Notably, patients without soft tissue release exhibited lower initial hip-knee-ankle (HKA) angles, reduced varus-valgus stress test angles, and a greater range of flexion. We identified a predictive threshold HKA angle of 6.250 degrees, demonstrating high sensitivity and specificity for determining the need for deep MCL release. CONCLUSION: This study underscores the significance of the initial HKA angle and varus-valgus stress tests in predicting deep MCL release during TKA. The established HKA angle threshold simplifies surgical decision-making, reducing the likelihood of unnecessary soft tissue release.

A novel robotic surgical assistant for total knee arthroplasty has a learning curve ranging from 6 to 14 cases and exhibits high accuracy in tibial bone cuts.

BACKGROUND: The adoption of robot-assisted total knee arthroplasty (TKA) aims to enhance the precision of implant positioning and limb alignment. Despite its benefits, the adoption of such technology is often accompanied by an initial learning curve, which may result in increased operative times. This study sought to determine the learning curve for the ROSA (Robotic Surgical Assistant) Knee System (Zimmer Biomet) in performing TKA and to evaluate the accuracy of the system in executing bone cuts and angles as planned. The hypothesis of this study was that cumulative experience with this robotic system would lead to reduced operative times. Additionally, the ROSA system demonstrated reliability in terms of the accuracy and reproducibility of bone cuts. METHODS: In this retrospective observational study, we examined 110 medical records from 95 patients who underwent ROSA-assisted TKA performed by three surgeons. We employed the cumulative summation methodology to assess the learning curves related to operative time. Furthermore, we evaluated the accuracy of the ROSA Knee System in performing TKA by comparing planned versus validated values for femoral and tibial bone cuts and angles. RESULTS: The learning curve for the ROSA Knee System spanned 14, 14, and 6 cases for the respective surgeons, with operative times decreasing by 22 min upon reaching proficiency (70.8 vs. 48.9 min; p < 0.001). Significant discrepancies were observed between the average planned and validated cuts and angles for femoral bone cuts (0.4 degree ± 2.4 for femoral flexion, 0.1 degree ± 0.6 for femoral coronal alignment, 0.3 mm ± 1.2 for distal medial femoral resection, 1.4 mm ± 8.8 for distal lateral femoral resection) and hip-knee-ankle axis alignment (0.3 degree ± 1.9 )(p < 0.05) but not for tibial bone cuts. Differences between planned and validated measurements during the learning and proficiency phases were nonsignificant across all parameters, except for the femoral flexion angle (0.42 degree ± 0.8 vs. 0.44 degree ± 2.7) (p = 0.49). CONCLUSION: The ROSA Knee System can be integrated into surgical workflows after a modest learning curve of 6 to 14 cases. The system demonstrated high accuracy and reproducibility, particularly for tibial bone cuts. Acknowledging the learning curve associated with new robot-assisted TKA technologies is vital for their effective implementation.

Enoxaparin versus No Anticoagulation Prophylaxis after Total Knee Arthroplasty in Thai Patients: A Randomized Controlled Trial.

Background: There has been some controversy about routine use of thromboprophylaxis after total knee arthroplasty (TKA) in Asian patients. Objective: To compare the efficacy and safety of enoxaparin in preventing venous thromboembolic diseases after TKA in Asian patients. Material and Method: We randomized 50 patients undergoing primary TKA into two equal groups, 25 patients received once daily subcutaneous enoxaparin injections as thromboprophylaxis and 25 control patients did not receive anticoagulation. The primary outcome was deep vein thrombosis (DVT) identified by color Doppler ultrasonography and/or pulmonary embolism (PE). All significant bleeding complications were recorded. Results: Deep vein thrombosis occurred in only one patient in the control group (4%) and in none in the enoxaparin group (0%, p = 0.31). No patient in both groups had clinical signs of PE. No patient had significant bleeding complications. One patient in enoxaparin group had a minor bleeding complication (4%) and also a surgical wound complication. Conclusion: We concluded that the incidence of thromboembolic diseases after primary TKA in Thai patients is very low. Enoxaparin had no significant benefit in reducing venous thromboembolic complications after TKA in Asian patients, however it is safe in term of bleeding complications. We do not recommend routine use of enoxaparin as thromboprophylaxis after TKA in Asian patients.

Effects of single shot femoral nerve block combined with intrathecal morphine for postoperative analgesia: a randomized, controlled, dose-ranging study after total knee arthroplasty.

OBJECTIVE: Pain after total knee arthroplasty (TKA) is severe, thus adequate pain control can be a challenge. Intrathecal morphine (ITM) provides excellent postoperative analgesia for TKA, but may have side effects. Femoral nerve block (FNB) also has been used for postoperative analgesia in TKA. We examined postoperative analgesia efficacy and side effects of ITM combined with single shot femoral nerve block (SSFNB) after TKA, over the dosage range of 0.0 to 0.3 mg. MATERIAL AND METHOD: Sixty patients undergoing elective TKA received SSFNB (0.5% bupivacaine 20 ml) and spinal anesthesia with 15 mg of hyperbaric bupivacaine (0.5% Heavy Marcaine) were included in this study. They were randomized to receive ITM (0, 0.1, 0.2, and 0.3 mg). A patient-controlled analgesia (PCA) device provided additional intravenous morphine. Morphine consumption, pain score, and side effects were recorded at 0, 1, 4, 8, 12, and 24 hour postoperative. Patient satisfaction was rated at the 24-hour postoperative visit. RESULTS: Morphine consumption was significant higher in 0 mg ITM group (control) than other groups, but there was no difference between ITM groups. Pain score was significant lower in 0.3 mg ITM group compared to 0 mg at 1 hour (0.5 vs. 3.5, respectively; p-value = 0.013) and 4 hour (1.5 vs. 4.5, respectively; p-value = 0.037) postoperative period Side effects were not different in all groups. CONCLUSION: The present study concluded that, low-dose ITM combination with SSFNB provided good pain relief with low side effects and reduced morphine consumption during the first 24 hours post TKA.