Despite total knee arthroplasty (TKA) being the gold standard for end-stage knee osteoarthritis, 20% of patients remain dissatisfied. Robotic-assisted arthroplasty promises unparalleled control of the accuracy of bone cuts, implant positioning, control of gap balance, and resultant hip–knee–ankle (HKA) axis. Patients underwent clinical and radiological assessments, including knee CT scans and patient-reported outcome measures (PROMs), preoperatively. Follow-up assessments were conducted at 2 weeks, 6 weeks, and 3 months post-operatively, with imaging repeated at 6 weeks. A total of 155 patients underwent robotic-assisted TKA and have completed 3 months of follow-up. Mean pre-operative HKA axis was 7.39 ± 5.52 degrees varus, improving to 1.34 ± 2.22 degrees varus post-operatively. Restoration of HKA axis was 0.76 ± 1.9 degrees from intra-operative planning (p < 0.0005). Implant placement accuracy in the coronal plane was 0.08 ± 1.36 degrees (p = 0.458) for the femoral component and 0.71 ± 1.3 degrees (p < 0.0005) for the tibial component. Rotational alignment mean deviation was 0.39 ± 1.49 degrees (p = 0.001). Most patients (98.1%) had ≤ 2 mm difference in extension–flexion gaps. PROM scores showed improvement and exceeded pre-operative scores by 6 weeks post-surgery. Robotic-assisted knee arthroplasty provides precise control over traditionally subjective factors, demonstrating excellent early post-operative outcomes.Level of evidence Prospective observational study—II.

Background: Only 80% of patients are satisfied with their outcomes post-TKA. Mounting attention has been paid to constitutional limb alignment and individualized alignment strategies in recent years. MacDessi et al. proposed the CPAK classification, which takes into account the patients’ arithmetic hip-knee-ankle axis (aHKA) and joint line obliquity (JLO). In this study, we aimed to establish local demographic data, compare them with published data, and assess their correlations with modifiable variables. Methods: A total of 500 end-stage osteoarthritic knees subjected to TKA were radiologically analyzed. The lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) were calculated from long limb radiographs before the aHKA and JLO were derived and a CPAK phenotype was assigned. Demographic data were harvested and analyzed for possible correlations. Results: There were 160 males (32%) and 340 females (68%), with a mean age of 66.42 years (range, 47–88). The mean MPTA was 85.8° (± 3.0)°, and the mean LDFA was 87.6° (± 2.4)°. The average aHKA was a varus of 1.8° (± 4.2)°, and the average JLO was 173.4° (± 3.45)°. The most common CPAK phenotype was Type 1 (43.4%). The Intraclass Correlation Coefficient demonstrated excellent reliability (> 0.9). No correlation existed between CPAK phenotypes and age, height, weight, or body mass index (BMI), but CPAK phenotype was significantly correlated with gender. Conclusion: An urban Malaysian population with osteoarthritic knees was found to be constitutionally varus, with the most common phenotype being varus aHKA with an apex-distal JLO. Constitutional alignment is not influenced by factors such as age, height, weight, or BMI. Level of Evidence: Retrospective Observational Study-III.

Background: In an ever-aging society that as a whole has become more affluent, significant emphasis has been accorded to an improved quality of life. Knee osteoarthritis is ever-increasingly treated with total knee arthroplasty. The benefits and satisfaction experienced by those who have undergone total knee replacements (TKR) are well documented in the literature. The issue arises when osteoarthritis of the affected knee is more complex than simple osteoarthritis, i.e. the patient has complex primary osteoarthritis. This collective term encompasses conditions such as massive bone loss, ligamentous laxity, coronal defects and those with contractures. There are various classifications to describe massive bone loss but we utilized the Anderson Orthopaedic Research Institute (AORI) classification. Numerous treatment options are available and we report the use of metaphyseal sleeves as a highly successful treatment option. Methods: We retrospectively reviewed all the patients at our centre who underwent primary TKR using the metaphyseal sleeves. Patients were assessed on symptoms and functional status, and radiographs were also taken to assess for osseointegration. Only patients who completed 2 years of follow up were included in our study. Results: The updated (2011) Knee Society Score (KSS) was used in conjunction with radiological assessments at each follow up. Mean KSS scores improved from 53.83 preoperatively to 193.39 postoperatively. All patients demonstrated increasing osseointegration throughout follow up. Conclusion: The metaphyseal sleeve is an excellent treatment option for complex primary osteoarthritic knees with good results objectively, functionally and radiologically and would be a great choice for all orthopaedic surgeons to include in their armamentarium.

The rapid adoption of robotic-assisted total knee arthroplasty (RATKA) has resulted in pre-operative CT scans becoming more readily available. After the segmentation and identification of landmarks by trained segmentation specialists, the Mako SmartRobotics^TM software generates measurements of interest for the calculation of the arithmetic hip-knee-ankle axis (aHKA), joint line obliquity (JLO), and the Coronal Plane Alignment of the Knee (CPAK) phenotype. The aim of this study is to ascertain how closely correlated these two sets of readings are and whether the CPAK distribution is altered when comparing both modalities. A retrospective radiological study was undertaken on 500 knees (367 patients: 133 bilateral, 234 unilateral) comparing the CT-based software-generated measurements of patients undergoing RATKA using the Stryker Mako system against manual measurements derived from long limb radiographs (LLRs). There were statistically significant differences between the average measurements of the LDFA (0.27 ± 2.95, p = 0.045), MPTA (1.15 ± 2.20, p < 0.001), aHKA (1.41 ± 3.85, p < 0.001) and JLO (0.89 ± 3.50, p < 0.001), with CT measurements having higher mean readings for LDFA, lower readings for MPTA, more varus aHKA and increased apex distal JLO. Despite this, correlation was moderately good: LDFA (r = 0.409, p < 0.001), MPTA (r = 0.683, p < 0.001), aHKA (r = 0.595, p < 0.001) and JLO (r = 0.456, p < 0.001). The CPAK distribution was also significantly different. LLRs underestimate the degree of constitutional varus and JLO compared to CT-based software-generated measurements, with a resultant increase in CPAK Types I and IV when using CT measurements. Despite moderately good correlation between both imaging modalities, there remains a statistically significant difference between them.

The integration of robotic systems in knee arthroplasty has accelerated, with early results indicating improved precision and outcomes. The ROSA^® Knee System facilitates the robotic-assisted positioning of cutting guides while enabling real-time assessment of ligament balance, with the surgeon retaining control of all bone resections. This study aimed to evaluate the precision of implant positioning, achievement of the planned hip–knee–ankle (HKA) axis, and consistency across different operating surgeons. A prospective observational study was conducted on patients undergoing robotic-assisted total knee arthroplasty (RATKA) using the ROSA Knee System. Radiographic assessments included pre- and post-operative AP/lateral knee and long-limb radiographs, supplemented with post-operative CT to assess femoral component rotation. Intra-operative alignment data recorded by the ROSA console were compared to post-operative imaging. Complication rates were also evaluated. Among 94 knees analyzed, the mean difference between intra-operative and post-operative HKA measurements was 1.66 ± 2.09°, which was statistically significant. Minor but significant differences were observed in LDFA (0.32 ± 1.84°, p = 0.034), MPTA (0.84 ± 1.17°, p < 0.001), and femoral component rotation (1.63 ± 2.40°, p < 0.001). No significant variation was noted in LDFA or MPTA between surgeons, though differences were present in rotational alignment and HKA. The intra-operative HKA showed moderate correlation with both measured post-op HKA and arithmetic HKA (aHKA), with slightly stronger correlation with the latter. The ROSA Knee System enables reproducible and accurate implant positioning with reliable restoration of the planned HKA axis. Once a surgeon is proficient, results are consistent without increased complication risks.

Introduction : Robotic-assisted total knee arthroplasty (RATKA) has been introduced to enhance surgical precision, alignment, and soft-tissue balancing, thus enabling the advent of numerous alignment philosophies including functional alignment (FA). This study aimed to compare early clinical outcomes, patient-reported outcome measures (PROMs), and radiographic accuracy brought about by RATKA using FA principles against the current reference standard of conventional total knee arthroplasty (TKA) and mechanical alignment (MA). Methods : This prospective, non-randomized cohort study included 45 patients undergoing primary unilateral TKA (30 RATKA, 15 conventional). Outcomes assessed were Visual Analogue Scale (VAS), Knee Society Score (KSS), and Knee injury and Osteoarthritis Outcome Score (KOOS) preoperatively and up to 1 year postoperatively. Forgotten Joint Score-12 (FJS-12) was evaluated at 1 year. Radiographic parameters included hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), lateral distal femoral angle (LDFA), and femoral component rotation. Alignment outliers were defined as a deviation of > ±3° from the target. Statistical significance was set at p < 0.05. Results : RATKA resulted in significantly lower VAS pain scores at 2 weeks and 3 months ( p < 0.05), with a consistent trend toward reduced pain at other timepoints. PROMs demonstrated improvements favoring RATKA across several KSS and KOOS subdomains at selected intervals. FJS-12 was higher in the RATKA group but did not reach statistical significance ( p = 0.12). Radiographic alignment was comparable between groups except for femoral component rotation, which showed greater external rotation in the conventional cohort ( p = 0.009). RATKA significantly reduced alignment outliers (10.0% vs 40.0%, p = 0.042). No complications were observed. Conclusion : The adoption of RATKA and functional alignment is associated with reduced early postoperative pain, modest improvements in PROMs, and improved consistency in achieving target alignment, without increased complications.