Patient Satisfaction After Robotic-Assisted Versus Conventional Total Knee Arthroplasty

• Type of Study: Randomized controlled trial.
• Study Setting: Ain Shams University hospitals
• Sampling Method: Consecutive sampling.
• Sample Size: A minimum of 70 patients with symptomatic end-stage primary knee osteoarthritis who meet the inclusion and exclusion criteria will be enrolled and randomly allocated into two groups, with 35 patients in each group.
• Study procedures:

Two-arm, parallel-group, randomized controlled trial comparing Mako4 robotic-arm assisted total knee arthroplasty with conventional total knee arthroplasty. Participants will be allocated in a 1:1 ratio using simple computer-generated randomization. Allocation will be concealed by an off-site holder of the randomization sequence who is independent of participant enrollment and outcome assessment. Outcome assessors will be blinded to treatment allocation, while participants and the operating surgical team will not be blinded because of the nature of the interventions.

Group A: Conventional Total Knee Arthroplasty (C-TKA). Group B: Robotic-Assisted Total Knee Arthroplasty (RA-TKA).

1. Primary (Preoperative) Diagnosis and Evaluation:
2. Clinical Evaluation
3. history

• Age, sex, occupation, level of activity, comorbidities, medical and surgical history
• To assess (BMI), The American Society of Anesthesiologists (ASA) score

1. General examination:

• Vital data (Heart Rate, Respiratory Rate, Blood Pressure, and peripheral pulsations)
• The Charnley Functional Classification based on patients' overall physical condition and comorbidities
• ligamentous laxity
• Spine, hip, foot and ankle examination
• Signs of inflammatory arthropathies (RA or SPA)

1. local examination

• Inspection, palpation, range of motion and special tests for ligaments integrity
• Preoperative scores: Oxford Knee Score (OKS), and 2011 Knee Society Score (KSS) objective knee indicators, Symptoms, Functional Activities, and Expectations Domains.

1. Radiological Evaluation:

PLAIN FILMS

• Weight bearing Anteroposterior (AP) knee Xrays
• Lateral knee Xrays (with knees in 30 ° flexion) to assess patellar height and component position
• Merchant view to assess the patella and the patellofemoral joint.
• Standing long-leg radiographs, obtained with the patellae facing forward and the feet flat on the ground

1. Overall, Limb Alignment

• Hip-Knee-Ankle angle (HKA)
• Mechanical axis deviation (MAD)

1. Femoral and tibial Parameters

• Mechanical Lateral Distal Femoral Angle (mLDFA)
• Mechanical Medial Proximal Tibial Angle (mMPTA)

1. Joint-Related Angles

• Joint Line Convergence Angle (JLCA)

1. Deformity Analysis

• Site (femoral vs tibial) and magnitude of deformity

1. preoperative patient preparation:

• All patients will undergo preoperative laboratory investigations (CBC with differentials, HBA1C, Bun, creatinine, Na, K, ALT, AST, PT, PTT, INR and Virology (HIV, HCV, HBV)
• ECG and echocardiogram to assess cardiac function
• Corresponding medical consultation according to their comorbidities II. intraoperative management: All patients will be managed by the same surgical team following a standardized perioperative protocol. Surgery will be performed with the patient in the supine position. Prophylactic intravenous antibiotics will be administered 30 minutes prior to skin incision in accordance with hospital policy, using weight-adjusted dosing. Above-knee pneumatic tourniquet will be applied in all cases. A standard medial parapatellar approach will be utilized. Total knee arthroplasty will be performed either using a conventional manual jig-based technique (C-TKA) (Group A) with a Fixed-bearing Posterior- Stabilized (PS) implants or robotic-assisted total knee arthroplasty (RA-TKA) (Group B), according to patient allocation. All implants and instrumentation will be provided by the same company (STRYKER). Regardless of surgical technique, all TKAs will be performed using cemented fixation. Stem extensions will be selectively used on a case-by-case basis in the presence of obesity, osteoporosis, or significant bone defects. The patella will be managed with conventional patelloplasty in all patients. Closed-suction drains will be used routinely. III. Postoperative management and follow up:

1. Rehab and medications: All patients will receive the same

• TKA education.
• Postoperative antibiotic and analgesia regimens (including Patient controlled Analgesia (PCA)).
• Venous thromboembolism prophylaxis protocol.
• Postoperative isometric quadriceps exercises, ankle pumps and straight leg raises
• Encouragement of immediate postoperative weight-bearing as tolerated on the day of surgery using a walker, along with initiation of early knee range-of-motion exercises.
• Postoperative CBC, wound and drain follow up

1. Radiological study:

• Immediate postoperative Xray knees Ap, lateral and if applicable; merchant view To check for implant position, retained cement and periprosthetic fractures.

With follow up at 6 weeks, 3months , 6 months and 1 year.

• Radiological outcomes will be assessed using the (KSRES) in the immediate postoperative period and at 6 months and 1 year postoperatively. The KSRES will be utilized to evaluate component alignment and positioning, radiolucent lines, osteolysis, component migration, and signs of aseptic loosening or implant failure,
• Standing long-leg radiographs, obtained with the patella facing forward and the feet flat on the ground, will be used to assess mechanical axis deviation and identify alignment outliers, defined as any postoperative alignment measurement deviating by more than 3° from the planned target alignment.

1. Computed tomography (CT) of the operated knee will be performed in the immediate postoperative period to assess femoral and tibial component rotational alignment and overall implant rotational profile.
2. Functional score At follow-up visits, the FJS-12, OKS, and ((2011 KSS) objective knee parameters, Symptoms, Functional Activities, fulfilled Expectations, and Satisfaction domains) will be recorded at 6 weeks, 3 months, 6 months, and 1 year and compared between both groups throughout follow-up.
3. Complications will be monitored and managed accordingly, e.g.: DVT, infection, periprosthetic fracture, implant loosening or failure .

Statistical Analysis:

By using Power Analysis and Sample Size Software (PASS 15) (Version 15.0.10) for sample size calculation, with a power of 80% and a significance level of 0.05, based on previous study results (Bollars et al., 2025), which reported that among patients undergoing total knee arthroplasty (TKA), patient satisfaction measured by FJS-12 was higher in those who underwent robotic-assisted TKA (mean 73.2 ± 23.3) compared to conventional instrumented TKA (mean 53.6 ± 29.0), and accounting for a 10% dropout rate; a sample size of at least 70 patients presenting with symptomatic end-stage primary knee osteoarthritis divided randomly into 2 groups (35 patients in each group) will be needed.