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Image-based robotic tools improve the accuracy of unicompartmental knee arthroplasty (UKA) positioning, but few studies have examined its effect on axial alignment. The aim of this study was to compare the characteristics of tibial and femoral implant positioning, mainly the tibial rotation, during medial or lateral UKA, performed with an image-based robotic assisted system.A total of 71 UKA performed between September 2021 and June 2022 (53 medial and 18 lateral) were analyzed. All data regarding implant positioning (rotation, coronal and sagittal alignment) for tibial and femoral components were obtained using MAKO® software (Stryker®, Mahwah, USA) intra-operatively.The lateral UKA had a mean internal tibial rotation of 15.4 ± 3°, a mean external femoral rotation of 0.96 ± 2.4°, and a mean tibial slope of 4.7 ± 1.3°. The medial UKA had a mean internal tibial rotation of 0.18 ± 2.7°, a mean internal femoral rotation of 0.35 ± 2.2°, and a mean tibial slope of 5.4 ± 1.3°. The tibial rotations, femoral valgus, tibial varus and tibial size significantly differed between medial and lateral UKA (p 0.05). There was no significant difference in femoral rotation, flexion, femoral size, slope, and polyethylene thickness between medial and lateral UKA.Medial and lateral UKA had significantly different implantation characteristics related to the biomechanics of the knee compartments. Image-based robotic UKA allowed precise femorotibial positioning per-operatively to match native kinematic alignment.

Implant malpositioning, joint line (JL) lowering, and malalignment have been identified as risk factors for implant failure in unicompartmental knee arthroplasty (UKA). The aims of this study were to compare the accuracy of implant positioning in robotic-assisted UKA versus conventional UKA in a large cohort and examine the correlation with implant survival at mid-term follow-up.This retrospective study included 356 medial UKAs from 2011 to 2019. The radiological measurements performed were coronal positioning of tibial implant according to Cartier angle (Δ Cartier), posterior tibial slope (PTS), residual hip-knee-ankle (HKA), and JL restoration. Outliers were defined as follows: post-operative HKA 175° or 180°, Δ Cartier 3° or - 3°, JL change ≥ 2 mm, and PTS 2° or 8°. The survival probability was reported at the last follow-up.Out of the 356 knees included, 159 underwent conventional UKA (44.5%) and 197 (55.5%) robotic-assisted UKA. The mean follow-up was 61.3 months ± 24.0. Robotic UKA was associated with better accuracy compared to conventional UKA in relation to HKA (67% vs 56%, p = 0.023), JL restoration (70% vs 44%, p 0.0001), PTS (83% vs 55%, p 0.0001), and tibial varus restoration (65% vs 55%, p = 0.049). Implant survival in the robotic group was found to be superior at the last follow-up (96.4% versus 87.3% at 9 years, p = 0.004).Robotic assistance in patients undergoing medial UKA was associated with better accuracy compared to conventional UKA with respect to tibial implant positioning, post-operative limb alignment, and JL restoration. This was translated in improved survival at mid-term follow-up favouring the robotic group.

The aim was to investigate the contribution of robotics assisted total hip arthroplasty (THA) through direct anterior approach (DAA) in improving radiographic precision, functional results and complications.This retrospective study compared 100 primary conventional THA (cTHA) to 50 primary robotic THA (rTHA) through DAA. All cups were placed with the objective of having no anterior overhang while respecting the safe zones (SZ). Radiographic analysis included cup inclination and anteversion, vertical and horizontal changes of the rotation centre (ΔVCOR, ΔHCOR), acetabular and femoral offset. SZ were 30-50° of inclination and 10-30° of anteversion. Outliers were defined as medial displacement of the COR 5 mm, vertical displacement of the COR 3 mm superiorly. Harris hip score (HHS) and complications were compared at one year of follow-up.The robotic cups were better oriented with 98% in the global SZ versus 68% in the cTHA group (p = 0.0002). The COR was on average better restored in the robotic group in both the horizontal and vertical planes (Δ HCOR = - 5.0 ± 5.0 vs - 3.4 ± 4.9, p = 0.03; Δ VCOR = 1.6 ± 3.3 vs 0.2 ± 2.7, p = 0.04). There were fewer outliers in the rTHA group concerning VCOR (28% versus 10%, p = 0.03). There was no significant difference in HHS and complication rate at one year.The use of robotics for THA by DAA provided an advantage in controlling the orientation of the cup and the restoration of its rotation centre. Thanks to the 3D planning on CT scan, it allowed to respect the thresholds while avoiding the anterior overhangs.

Purpose The ability of kinematic alignment (KA) to consistently restore trochlea anatomy in total knee arthroplasty (TKA) is unknown despite recreation of constitutional anatomy being its rationale for use. The purpose of this study was to assess if alignment choice in TKA effects the ability to restore the native trochlea groove. Methods One hundred and twenty-two consecutive patients undergoing robotic-assisted TKA using the MAKO image-based robotic platform had simulated femoral components placed according to kinematic, mechanical and functional alignment principals. Implant position and trochlea restoration between groups were compared. Restoration was assessed by shift (medial–lateral) and depth relative to the native groove from three consistent points; full extension (0°), mid-flexion (30°–40°) and deep flexion (70°–80°). Results Three hundred and sixty-six alignment options were analysed. Femoral alignment was significantly different between groups. Of KA, 13.1% compared to 3.3% of FA plans were outside safe coronal boundaries. The trochlear groove was translated the most by MA compared to KA and FA (full extension, MA 7.84 ± 1.99 mm lateral to the native groove, KA 6.40 ± 2.43 mm and FA 6.88 ± 1.74 mm, p ≤ 0.001). In full extension, FA most closely restored the trochlear groove depth in all three positions of flexion. Conclusion Alignment philosophy led to significant differences in trochlea groove recreation. A kinematically placed femoral component led to positioning considered unsafe in over 13% of cases. A functionally placed femoral component most closely restored trochlea depth in all three positions of flexion.

Anterior cruciate ligament (ACL) deficiency can be a consequence or a cause of femoro-tibial osteoarthritis (OA). Several studies have published satisfactory outcomes of unicompartimental knee arthroplasty (UKA) and combined ACL reconstruction despite its absence classically being considered a contraindication. A major challenge in the ACL deficient knee is obtaining appropriate gap balancing and limb axis. Robotically assisted UKA allows for precise control of these factors; however, it's utilisation as a tool with combined ACL reconstruction and UKA has not been described. The purpose of this study was to evaluate the clinical and radiological outcomes of robotically assisted UKA with combined ACL reconstruction.This was a retrospective single-centre study of ten patients operated by a single surgeon from 2016 to 2020. All surgery was performed using a cemented fixed bearing UKA prosthesis (Journey uni, Smith and Nephew®) (8 medial, 2 lateral) inserted with the assistance of an image-free robotic-assisted system (BlueBelt, Navio, Smith and Nephew®). All ACL reconstructions were performed using hamstring autograft. Clinical assessment included International Knee Score (IKS) score, Tegner score and patient satisfaction. Radiological assessment was performed to assess radiolucent lines, progression of OA in the other compartments, Hip-Knee-Ankle angle and Posterior Tibial Slope.There were eight females (80%), mean age was 57 ± 7 [48-70], mean BMI was 26 ± 3 [22-31]. The mean follow-up was 45 months ± 13 months [24-66]. Mean post-operative IKS knee and function score were respectively 96 ± 4.5 [88-100] and 93 ± 8.2 [74-100], mean Tegner score was 4.5 ± 1.4 [3-6]. Nine patients (90%) returned to sport; one patient (10%) was dissatisfied because of residual pain preventing a return to a desired level of sport. 100% of the radiological objectives were achieved. No radiolucent lines were seen at the last follow-up. There were two re-operations (20%) for stiffness requiring arthroscopic arthrolysis at two and three months respectively following surgery, with full recovery of the flexion at the last follow-up in both cases. No other complications were observed.Robotic UKA associated with ACL reconstruction provides satisfactory early patient outcomes and accurate implant positioning. The first results in terms of return to sports were promising.

Reverse shoulder arthroplasty (RSA) is often indicated in elderly patients with displaced proximal humerus fractures (PHF). The rate of greater tuberosity (GT) healing varies from 37 to 90% in this population. The aim of this study was to assess greater and lesser tuberosity (LT) fixation and healing on CT scan after RSA for PHF. Our hypothesis was that both GT and LT healing leads to better functional results after RSA for fracture. Our retrospective cohort consisted of 28 patients treated with an RSA for a four-part PHF during the inclusion period. The mean age at surgery was 77 years. Clinical examination and CT scan were performed at a minimum one year follow-up to assess tuberosity position and healing. The GT healed in 22 patients (78.5%), the LT in 24 patients (87.5%) and both tuberosities were healed in 20 patients (71.5%). Constant score was significantly improved with GT, LT and both tuberosity healing (p = 0.05, p = 0.04 and p = 0.02 respectively). Motion in anterior elevation was improved with GT and both tuberosity healing (p = 0.01 and p = 0.04 respectively). Motion in external rotation was improved with GT and both tuberosity healing (p = 0.01 and p = 0.02 respectively). GT and LT healing was associated with better functional results and active motion. Anatomical reduction and consolidation of both tuberosities is beneficial with a cumulative effect for functional recovery.

PURPOSE: Cup positioning is important for optimum hip stability, avoiding component impingement and decreasing both bearing surface wear and revision rate. Transitioning from posterior approach in a lateral position to direct anterior approach (DAA) in a supine presents unique challenges for surgeons. The aim of this study was to examine the learning curve when using standard instrumentation that was not specific to DAA. METHODS: A consecutive retrospective series of 537 total hip arthroplasty by DAA from May 2013 to December 2017. Cup positioning was analysed on radiographs and classified whether inside or outside two safe zones (inclination 30-50° and anteversion 10-30°). The demographic data (age, BMI, gender, neck shaft angle (NSA)), surgeon's dominant side and experience were assessed as risk factors. RESULTS: Eighty per cent of cups (n=426) were in the combined safe zones. Eighty-eight per cent (n=470) were in appropriate anteversion and 87% (n=463) abduction. Two factors that were significant were identified: Cups of left hips operated by right-handed surgeons were more anteverted (OR=4.06) and more vertical (OR=2.23); females had a higher anteversion of the cup (OR=2.42). Obesity, age and NSA were not risk factors for cup malposition. There was a spike of cups too horizontal at the beginning of the experience (OR=3.86), and no learning curve was observed in the other orientations. CONCLUSION: With our DAA technique using standard instrumentation, there were no risk factors linked to the patient identified for cup malposition. DAA-specific instrumentation is not required to achieve optimum positioning of the cup. Surgeon has to be aware of an excess of abduction at the beginning of his experience and an excess of anteversion and adduction when performing THA on the opposite side of his dominant hand.

The aim of this study was to evaluate the radiographic effect of sagittal tibial osteotomy (STO), flexion tibial osteotomy (FTO) and deflexion tibial osteotomy (DTO) around the knee. It has been hypothesized that proximal STO modifies patellar height and could cause varus/valgus changes of the anatomical tibial axis: The purpose of the study was to verify this and to analyse these modifications. Patients underwent proximal STO in our department between 2007 and 2018: overall 28 consecutive patients (19 males, 9 females; 28 knees). Twelve patients underwent DTO, and 16 patients underwent FTO. Two independent observers measured the pre-operative and post-operative radiological indexes: posterior tibial slope, Caton-Deschamps Index (CDI) and Modified Insall-Salvati Index (MISI) in the lateral views; medial Tibial Plateau-Tibial Shaft (mTPTS) and medial Femoral Shaft-Tibial Shaft (mFTA) anatomical angles were measured in the frontal plane. No complications were reported at the average follow-up of 1.6 ± 1.1 years. The mean mTPTS significantly increased from 0.6° ± 2.4° pre-operatively to 2.9° ± 2.6° of varus post-operatively (DTO (pre-operative 0.3 ± 3.1°, post-operative 2.4 ± 2.1°, ns); FTO (pre-operative 0.9 ± 1.9°, post-operative 3.2 ± 3.0°, P