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Introduction: Restoration of the anterior knee compartment is increasingly studied with the development of personalized surgery. However, evaluating the patellar tracking during the surgery is still subjective and at the surgeon’s discretion. This study aimed 1) to describe the assessment of the patellar tracking during robotic-assisted total knee arthroplasty (TKA), 2) to describe a new measurement technique for evaluating the evolution of this patellar tracking, and 3) to assess its reliability and repeatability. Method: This monocentric study assessed the evolution of patellar tracking for 20 robotic-assisted TKA. The sharp probe was used to perform patellar tracking in all the arcs of knee flexion before and after the bone cuts. The patella positioning was recorded every 10° of flexion between the full extension and 90° knee flexion and was assessed in the coronal and sagittal planes. For the measurements of the patellar tracking, we used a sagittal view and a coronal view of the knee on the MAKO software. From these two views, the difference between the patellar tracking before and after the bone cuts with the definitive implants was measured. Two independent reviewers performed the measurements to assess their reliability. To determine intraobserver variability, the first observer performed the measurements twice. Results: The mean age was 68.7 years old ± 5.2 [61; 75], the mean body mass index was 28.8 kg/m2 ± 4.2 [21.4; 36.2], the mean HKA angle was 176.3° ± 3.7° [174.1.4; 179.7]. The radiographic measurements showed very good to excellent intra-observer and inter-observer agreements (0.60 to 1.0). Conclusion: This new measurement technique assessed the evolution of patellar tracking after TKA with good inter and intra-observer reliability.

Introduction: This study aimed to compare the revision rate and long-term survival between two generations of uncemented dual mobility cup (DMC) from the same manufacturer in primary total hip arthroplasty (THA) at a minimum follow-up of 10 years. Methods: This retrospective monocentric study included all THA performed with an uncemented DMC from the same company. The cohort included 150 patients with 22 first-generation DMC and 128 second-generation DMC. The coating of the second generation was a double-coating Plasma spray of Titanium and Hydroxyapatite (HAP), compared to the coating of alumina and HAP for the first generation. The mean follow-up was 14.2 ± 1.2 years. The mean age was 76.0 ± 10.1 years. The Harris hip score (HHS), complications, and revisions were collected at the last follow-up. Ten- and fifteen-year Kaplan-Meier survival was calculated. Results: At the last follow-up, the mean HHS was 83.2 ± 9.1. There were two acetabular loosenings with the old coating (9.1%) and one case with the new one (0.78%) (p = 0.056). There was one extra-prosthetic dislocation (0.67%) and one postoperative infection (0.67%). Survival without acetabular revision at 10 and 15 years was 90.9% for the 1st generation and 99.2% for the 2nd generation (p = 0.009). Conclusion: Survival without acetabular revision was significantly higher at 10 and 15 years of follow-up with the second generation of DMC with plasma-sprayed titanium and HAP coating compared to the first generation of DMC coat. The dislocation was uncommon, thanks to the dual mobility concept. This second generation of uncemented DMC can be safely used in primary THA.

Introduction: Simultaneous bilateral total hip arthroplasty (THA) has demonstrated similar clinical outcomes to staged bilateral THA. However, there is scarce data regarding the early postoperative complications. This study compares simultaneous to staged bilateral THA with the direct anterior approach (DAA) regarding early complications and revision surgeries. Methods: This retrospective case-control study included all bilateral THAs, performed by DAA between 2013 and 2021 with a minimum follow-up of 6 months. A total of 264 THAs (132 patients) were identified [simultaneous group (1T): 58 patients; staged group (2T): 74] with a mean follow-up of 54 months. Complications and revisions, clinical outcomes, and days off work were assessed at the last follow-up. Moreover, blood loss was evaluated by the modified method of Mercuriali and Inghilleri. Results: Blood loss was higher in the 1T group (1003 mL 1T vs. 740 mL 2T; p

Introduction: This study aimed to systematically review the literature and identify the surgical management strategy for fixed flexion contracture in primary total knee arthroplasty (TKA) surgery, pre-, intra-, and post-operatively. Secondary endpoints were etiologies and factors favoring flexion contracture. Materials and methods: Searches were carried out in November 2023 in several databases (Pubmed, Scopus, Cochrane, and Google Scholar) using the following keywords: “flexion contracture AND TKA”, “fixed flexion deformity AND TKA”, “posterior capsular release AND TKA”, “posterior capsulotomy in TKA”, “distal femoral resection AND TKA”. Study quality was assessed using the STROBE checklist and the Downs and Black score. Data concerning factors or strategies leading to the development or prevention of flexion contracture after TKA were extracted from the text, figures, and tables of the included references. The effect of each predictive factor on flexion contracture after TKA was recorded. Results: Thirty-one studies were identified to meet the inclusion and exclusion criteria. These studies described a variety of preoperative and intraoperative factors that contribute to the development or correction of postoperative flexion contracture. The only clearly identified predictor of postoperative flexion contracture was preoperative flexion contracture. Intraoperative steps described to correct flexion contracture were: soft-tissue balancing (in posterior and medial compartments), distal femoral resection, flexion of the femoral component, and posterior condylar resection. However, no study has investigated these factors in a global model. Discussion: This review identified various pre-, intra-, and post-operative factors predictive of post-operative flexion contracture. In practice, these factors are likely to interact, and it is therefore crucial to further investigate them in a comprehensive model to develop an algorithm for the management of flexion contracture. Level of evidence: IV

Introduction: The COVID-19 pandemic has significantly affected access to timely care for patients with hip osteoarthritis requiring total hip replacement (THR). This study aimed to assess the changes in surgical activity, outpatient treatment, length of stay (LOS), discharge destinations, readmission rates, clinical outcomes, and patient satisfaction before and after the pandemic at our institution. Materials and methods: This retrospective study encompassed patients undergoing primary THR through the direct anterior approach at a single university hospital. Data on demographic characteristics, surgical technique, perioperative management, LOS, discharge destinations, complications, and clinical outcomes were collected. Furthermore, a comparative analysis between the pre-pandemic (2019) and post-pandemic (2022) periods was conducted. Results: There was a 14% increase in surgical activity post-pandemic, with 214 patients undergoing surgery in 2019 versus 284 in 2022. The percentage of patients managed as outpatients significantly increased from 0.5% in 2019 to 29.6% in 2022 (p

Introduction: There have been controversial studies on the impact of prior knee arthroscopy (KA) on outcomes of total knee arthroplasty (TKA). The purpose of this comparative study is to investigate the impact of prior KA of medial meniscus on patients undergoing TKA by evaluating the International Knee Society Score (IKS), the complications, and revisions. Methods: This retrospective study reviewed 84 patients with TKA who had undergone prior KA of the medial meniscus and compared them to 84 cases, without a history of prior KA as a control group. Outcomes were assessed with the original IKS scores and complications. The mean follow-up was 8 years. Results: There was no significant difference between groups with respect to demographics, or pre-operative IKS. The mean pre and postoperative IKS was not different between groups. The all-cause reoperation, revision, and complication rates of the KA group were not significantly higher than those of the control group. Conclusion: The present study seems to reveal that previous KA of the medial meniscus does not negatively affect a subsequent TKA. Nevertheless, larger studies may be necessary to confirm this observation.

Introduction: The new concepts in total knee arthroplasty (TKA) tend to improve the alignment and ligament balancing after TKA. Nevertheless, the assessment of the anterior compartment is difficult. The purpose of this study was to describe a new measurement technique of trochlear offset restoration on CT-scan after primary robotic-assisted TKA and assess its reliability and repeatability. Method: This monocentric study assessed the trochlear offset restoration on a CT scan after 20 robotic-assisted TKA. To evaluate the trochlear offset restoration, we measured the depth difference between the native and the prosthetic trochlea. Four sequential positions were assessed on the trochlea: at full extension, at 30°, 70°, and 90° flexion. For each of these positions, we compared the highest point of the lateral native condyle and the lateral prosthetic condyle, the highest point of the medial native condyle and the medial prosthetic condyle, the deepest point of the native trochlear groove and the prosthetic trochlea. Two independent reviewers performed the measurements to assess their reliability. To determine intraobserver variability, the first observer performed the measurements twice. Results: The mean age was 67.3 years old ± 8.3. Mean values of the trochlear offset restoration for the medial condyle, trochlear groove and lateral condyle were respectively: 1.0 mm ± 1.6, 1.1 mm ± 1.5, −2.7 mm ± 2.3 in full extension; −3.5 mm ± 1.7, −1.5 mm ± 1.7, −3.9 mm ± 3.9 at 30° flexion; −5.1 mm ± 1.8, 2.1 mm ± 2.7, −3.8 mm ± 1.8 at 70° flexion; 2.0 mm ± 1.4 and 3.1 mm ± 1.5 for the medial and lateral condyles at 90° flexion. The radiographic measurements showed very good to excellent intra-observer and inter-observer agreements with mean kappa values of 0.92 and 0.74. Conclusion: We present a novel measurement technique on CT scan for evaluating the restoration of the trochlear offset after TKA, demonstrating excellent inter and intra-observer reliability.

Introduction: This study aimed to determine the incidence of offset stem usage in revision total knee arthroplasty (rTKA), and to assess the necessity for their use with the femoral and tibial components. Methods: This retrospective radiological study included 862 patients who underwent rTKA between 2010 and 2022. Patients were divided into a non-stem group (group NS), offset stem group (group OS), and straight stem group (group SS). Two senior orthopedic surgeons evaluated all the post-operative radiographs of the group OS to assess the necessity of offset use. Results: In total, 789 patients met all eligibility inclusion criteria and were reviewed (305 males (38.7%)) with a mean age of 72.7 ± 10.2 years old [39; 96]. Eighty-eight (11.1%) patients had undergone rTKA with offset stems (34 tibia, 31 femur, 24 both) and 609 (70.2%) with straight stems. The tibial and femoral stems were diaphyseal of over 75 mm in 83 revisions (94.3%) for group OS and 444 revisions (72.9%) for group SS (p

Introduction: Nitride-based ceramic coating was introduced into surgical implants to improve hardness, reduce abrasion, and decrease the risk of metal-induced adverse reactions, especially for patients with suspected or identified metal hypersensitivity. The study aimed to evaluate the effectiveness and safety of a titanium nitride (TiN) coated prosthesis with a mobile bearing design. Methods: This was a retrospective matched-cohort study from a single center, comparing clinical outcomes between patients receiving either a TiN-coated versus an uncoated cobalt-chromium-molybdenum (CoCrMo) prostheses for primary total knee replacement. Seventeen patients received the TiN prosthesis between 2015 and 2019. These were matched 1:2 with patients receiving uncoated mobile-bearing knee prostheses with the same design manufacturer. Results: Fourteen patients in the TiN group had complete 5-year follow-up data and were compared with 34 patients from the CoCrMo group. The Knee Society Score was 170.6 ± 28.0 (Function subscore 83.7 ± 17.5 and Knee subscore 86.9 ± 13.8) in the TiN group and 180.7 ± 49.4 (Function subscore 87.5 ± 14.3 and Knee subscore 93.2 ± 9.6) in CoCrMo group, with no statistically significant difference (p = 0.19). One patient underwent a revision for instability requiring the removal of the implant in the TiN group and none in the CoCrMo group. The survival rates were 92.9% (CI95% 77.3–100.0) and 100.0% in the TiN group and CoCrMo group respectively (p = 1.0). Discussion: TiN-coated TKA with mobile bearing resulted in satisfactory clinical outcomes, and a low revision rate, and there was no complication related to the coated implant. The use of TiN-coated prostheses in case of confirmed or suspected metal allergy provides satisfactory short-term clinic outcomes.

Introduction: Despite its excellent results in preventing dislocation, the dual mobility cup (DMC) is still struggling to be adopted by some teams due to premature wear and loosening reported on first-generation implants. Therefore, this study aimed to assess the mid-term survivorship of a modern DMC with a pre-impacted head and the radio-clinical results at a minimum follow-up of 5 years. Methods: This was a retrospective single-centre study performed on patients who had a primary total hip replacement for osteoarthritis in 2016. The cup was a third-generation DMC with a pre-impacted femoral head. Clinical (harris hip score (HHS)) and radiological (cup abduction, anteversion, overhang, and radiolucent lines) results were recorded, as well as complications, particularly dislocations and survivorship. A minimum of five years of follow-ups was required. Results: One hundred and seventy-five hips (167 patients) met the inclusion criteria. Five hips (2.9%, 5/175) were lost to follow-up and excluded from the postoperative analysis. The mean follow-up period was 70 ± 2.9 months [63.6–76.5]. Three cups needed revision surgery (1.8%, 3/170): one for septic loosening, and two for chronic infection. At 77 months, the global survival probability was 98.2% ± 1, and the survival probability excluding septic aetiology was 100%. There was a significant improvement in the HHS from pre-operatively (48.3 ± 6.0 [14.0–70.0]) to post-operatively (96 ± 4.5 [50–100]) (p

Introduction: Unicompartmental knee arthroplasty (UKA) has traditionally been contraindicated in the presence of an ACL deficient knee, bi-compartmental disease, or significant coronal deformity due to concerns regarding increased risk of persisted pain, knee instability, tibial loosening, or progression of osteoarthritis. The aim of this study was to evaluate the outcomes of patients undergoing UKA with an associated surgical procedure in these specific indications. Method: This was a retrospective cohort study of patients undergoing UKA between December 2015 and October 2020. Patients were categorized into groups based on associated procedures: UKA + ACL, UKA + HTO, and bicompartmental arthroplasty. Outcomes were assessed using the Knee Society Score (KSS) knee and function scores and the Forgotten Joint Score. Radiological and complication analysis was performed at the last clinical follow-up. Results: Thirty-two patients (13 men and 19 women) were included. The mean age was 56.2 years ± 11.1 (range, 33–84) with a mean follow-up of 26.3 months ± 15 (7.3–61.1). There was a significant improvement between the pre-and postoperative KSS Knee (+34.3 ± 16.5 [12–69]), Function (+34.3 ± 18.6 [0–75]), and Total scores (+68.5 ± 29.4 [24–129]) (p = 0.001). Seven patients (21.8%) required an arthroscopic arthrolysis for persistent stiffness. Two patients (UKA + PFA and UKA + ACL) underwent revision to TKA. Patient satisfaction was 90%, and mean flexion at last follow-up was 122° ± 6 (120–140). The implant survival rate was 94%. Discussion: This study found performing UKA with an additional procedure to address relative contraindications to the arthroplasty in physically active patients with monocompartmental knee arthritis is an efficient strategy with good results at short-term follow-up. It should be reserved for patients where TKA is likely to have unsatisfactory results, and the patient has been fully counseled regarding the management options. Even if there is a high rate of complications with stiffness requiring a re-intervention, the final results are very satisfying with no impact of the reintervention on the clinical result in the short term.

Introduction: Patella instability post total knee arthroplasty (TKA) is a rare complication. Tibial tubercle osteotomy (TTO) with medial patellofemoral ligament reconstruction (MPFLr) has not been well described for this indication. This paper describes a surgical technique to address the unique challenges faced when performing TTO and MPFLr in the prosthetic knee. Technique: This technique and video describe a TTO and MPFLr via an extensile incision and medial sub-vastus approach. A 6 cm long TTO is performed, if indicated, to medialise the extensor mechanism up to 1 cm and fixed with ×2 4.5 mm cortical screws. For the MPFLr, a quadriceps tendon autograft is utilized, with the natural insertion to the superior pole of the patella being left undisturbed. The graft is first attached with an interference screw and then reinforced with an endobutton to provide crucial cortical fixation to overcome the problem of low bone mineral density encountered in this area of the femur following TKA. Results: Five patients underwent MPFLr using the described technique. No failures or recurrence of instability occurred at the last follow-up. Pre-operative mean patella tilt and shift were 44° and 3.5 cm, respectively. Post-operatively, mean tilt and shift were 4.1° and 0.4 cm, respectively. There was one wound dehiscence requiring surgical debridement and closure. Conclusion: This paper describes a surgical technique to perform a TTO and MPFLr for patella instability post-TKA. The described method highlights key adaptations to address the unique challenges in this patient population.

Traditionally in total knee arthroplasty (TKA), a post-operative neutral alignment was the gold standard. This principle has been contested as functional outcomes were found to be inconsistent. Analysis of limb alignment in the non-osteoarthritic population reveals variations from neutral alignment and consideration of a personalized or patient-specific alignment in TKA is challenging previous concepts. The aim of this review was to clarify the variations of current personalized alignments and to report their results. Current personalized approaches of alignment reported are: kinematic, inverse kinematic, restricted kinematic, and functional. The principle of “kinematic alignment” is knee resurfacing with restitution of pre-arthritic anatomy. The aim is to resurface the femur maintaining the native femoral joint line obliquity. The flexion and extension gaps are balanced with the tibial resection. The principle of the “inverse kinematic alignment” is to resurface the tibia with similar medial and lateral bone resections in order to keep the native tibial joint line obliquity. Gap balancing is performed by adjusting the femoral resections. To avoid reproducing extreme anatomical alignments there is “restricted kinematic alignment” which is a compromise between mechanical alignment and true kinematic alignment with a defined safe zone of alignment. Finally, there is the concept of “functional alignment” which is an evolution of kinematic alignment as enabling technology has progressed. This is obtained by manipulating alignment, bone resections, soft tissue releases, and/or implant positioning with a robotic-assisted system to optimize TKA function for a patient’s specific alignment, bone morphology, and soft tissue envelope. The aim of personalizing alignment is to restore native knee kinematics and improve functional outcomes after TKA. A long-term follow-up remains crucial to assess both outcomes and implant survivorship of these current concepts.

Introduction: One of the principal complications after total knee arthroplasty (TKA) is stiffness. There are no publications concerning stiffness after unicompartmental knee arthroplasty (UKA). Study objectives were to describe the incidence of stiffness after UKA, to look for risk factors, and to describe safe and effective arthroscopic treatment. Methods: There were 240 UKA performed between March 2016 and January 2019 included. Robotic-assisted surgery was performed in 164 patients and mechanical instrumentation in 76 patients. Stiffness was defined as flexion < 90° or a flexion contracture > 10° during the first 45 post-operative days. Patients with stiffness were treated with arthroscopic arthrolysis. Several factors were studied to look for risk factors of stiffness: body mass index, gender, age, mechanical or robotic instrumentation, preoperative flexion, previous meniscectomy, and anticoagulant treatment. Arthrolysis effectiveness was evaluated by flexion improvement and UKA revision rate. Results: 22 patients (9%) developed stiffness. Mechanical instrumentation significantly increased the risk of stiffness with OR = 0.26 and p = 0.005. Robotic-assisted surgery decreased the risk of stiffness by five-fold. Before arthrolysis, mean knee flexion was 79°, versus 121° (53% improvement) after arthroscopic arthrolysis. Only 2 patients (9%) underwent UKA revision after arthrolysis. Discussion: Stiffness after UKA is an important complication with an incidence of 9% in this study. Arthroscopic arthrolysis is a safe and effective treatment with a range of motion improvement of > 50%. Robotic-assisted surgery significantly decreases the risk of postoperative stiffness. Level of evidence: Level III, therapeutic study, retrospective cohort study

Purpose: This study aimed to evaluate whether there are any differences in outcomes and complication rates between condylar constrained knee (CCK) and rotating hinge knee (RHK) prostheses used for the first revision of total knee arthroplasty (rTKA) after mechanical failure. Methods: Sixty-three consecutive non-septic revisions of posterior stabilized implants using 33 CCK and 30 RHK prostheses were included. Clinical evaluation and revision rate were compared between the two groups at two years minimum follow-up. Results: The CCK group had significantly better clinical outcomes and satisfaction rates compared to patients with RHK (KSS-knee 70.5 versus 60.7 (p

Introduction: The design of uncemented femoral stems for use in total hip arthroplasty has evolved. Several uncemented short stems have been developed with different bone fixations, shapes, or stem lengths. The literature analyzing the biomechanical performance of short to standard stem lengths is limited. The aim was to compare the stress repartition on a standard uncemented stem and a shortened uncemented femoral stem with the same design features. Material and methods: This finite element analysis assessed the stress repartition on two femoral components with the same design (uncemented, collared, proximal trapezoidal cross-section, and a tapered quadrangular distal stem) but with two different lengths. The shortened stem was shorter by 40 mm compared to the standard stem. The stress repartition was analysed according to the Von Mises criterion. Results: The stress repartition was similar for the standard and shorter stem without significant difference (p = 0.94). The mean Von Mises stress was 58.1 MPa [0.2; 154.1] for the standard stem and 57.2 MPa [0.03; 160.2] for the short stem. The distal part of the standard stem, which was removed in the short stem, had mean stress of 3.7 MPa [0.2; 7.0]. Conclusion: The finite element analysis found similar stress repartitions between a standard uncemented collared stem and a short, collared stem with the same design. A clinical study assessing the clinical outcomes and the bone remodelling with a collared short stem would be interesting to confirm these first promising results.

Introduction: Ceramic-on-ceramic couplings are an alternative bearing surface to reduce the problems related to polyethylene wear and debris. However, ceramic articulations have their own risk of unique complications: fracture, squeaking, or dislocation. Few studies have assessed the outcomes of ceramic-on-ceramic total hip arthroplasties (THA) by direct anterior approach (DAA). The aim was to evaluate the early complications and revision rate of ceramic-on-ceramic THA by DAA. Material: A retrospective single-center study of 116 consecutive THAs was performed by DAA (106 patients) with ceramic-on-ceramic bearing from January 2015 to February 2018 with a minimum 24 months of follow-up. No patients were lost to follow-up. The mean age was of 55.3 years ± 11.3. The same cementless acetabular shell with a Biolox Delta ceramic insert and head were used. The complication and revision rates were collected at the last follow-up. The positioning of the acetabular implant was assessed on standard radiographs. Postoperative clinical outcomes were assessed by the Harris Hip Score. Results: At a mean follow-up of 31.9 months ± 5.5, no THA was revised. Five patients had late complications: 3 squeaking (2.6%) and 2 psoas impingements (1.7%) and were managed conservatively. All patients had satisfactory bony ingrowth of acetabular component, with no radiolucent lines and no osteolysis. Eight patients (6.9%) had an anterior overhang of the cup. The mean overhang for these patients was 4.1 mm. 111 hips (96%) were perceived as forgotten or having no limitations. Conclusion: This ceramic-on-ceramic coupling and shell by DAA produced excellent clinical outcomes and implant survival rate at a minimum two-year follow-up study. No serious complication was observed during the follow-up.

Since its creation in 1974, the Dual Mobility Cup (DMC) has been gaining in popularity, especially in the past decade. This intensive use could lead to inappropriate use and consequently to an increased complication rate. Compliance with conceptual requirements and surgical techniques will prevent the occurrence of complications that can be wrongly attributed to implants. In this context, we feel that it is essential to share our tips and tricks as well as an overview and an explanation of common errors, based on more than 45 years of clinical and research experience. From basic principles, including indications, implant choice and implant compatibility, to surgical tips, in this article orthopedic surgeons will find a practical overview of DMC in order to use it safely and with confidence.

Introduction: PJI is the most dramatic complication after joint arthroplasty. In patients with chronic infection, prosthesis exchange is in theory the rule. However, this surgical approach is sometimes not desirable especially in elderly patients with multiple comorbidities, as it could be associated with a dramatic loss of function, reduction of the bone stock, fracture, or peroperative death. We propose here to report different approaches that can help to maintain the function in such patients based on a pathophysiology-, multidisciplinary-, and an experience-based approach. Methods: We describe the different points that are needed to treat such patients: (i) the multidisciplinary care management; (ii) understanding the mechanism of bacterial persistence; (iii) optimization of the conservative surgical approach; (iv) use of suppressive antimicrobial therapy (SAT); (v) implementation of innovative agents that could be used locally to target the biofilm. Results: In France, a nation-wide network called CRIOAc has been created and funded by the French Health ministry to manage complex bone and joint infection. Based on the understanding of the complex pathophysiology of PJI, it seems to be feasible to propose conservative surgical treatment such as “debridement antibiotics and implant retention” (with or without soft-tissue coverage) followed by SAT to control the disease progression. Finally, there is a rational for the use of particular agents that have the ability to target the bacteria embedded in biofilm such as bacteriophages and phage lysins. Discussion: This multistep approach is probably a key determinant to propose innovative management in patients with complex PJI, to improve the outcome. Conclusion: Conservative treatment has a high potential in patients with chronic PJI for whom explantation is not desirable. The next step will be to evaluate such practices in nation-wide clinical trials.

Introduction: Total knee arthroplasty (TKA) remains the treatment of choice for severe osteoarthritis of the knee and nearly 60% of patients undergoing TKA are women. Females present three notable anatomic differences. Thus, gender-specific (GS) components were introduced to accommodate the females’ anatomic differences. No systematic review has been published since 2014. The aim of this study was to perform a recent systematic review of the literature to determine whether there is any clinical benefit of gender-specific implants compared to conventional unisex implants in total knee arthroplasty (TKA). Methods: This study included prospective randomized controlled trials (PRCTs) comparing clinical and radiological outcomes, and complications in TKA with gender-specific implants and conventional implants. All studies had a minimum follow-up of two years. Results: Three PRCTs published between 2010 and 2012 were included. These studies showed a low risk of bias and were of very high quality. We did not find superior clinical outcomes for gender-specific prostheses compared to conventional prostheses. However, gender-specific TKA reduced the number of patients with femoral component overhang compared to conventional TKA. Conclusion: In our systematic review, despite a lower overhang rate, gender-specific implants in female TKA showed no clinical benefit over standard unisex implants. Good clinical results with significant improvement were observed with both designs. There is a notable absence of new studies on this subject in recent years, and further research needs to be performed using various gender-specific implant designs to further define the role of gender-specific implants. Level of evidence: Systematic review, Level IV

Introduction: Proficiency in the direct anterior approach (DAA) as with many surgical techniques is considered to be challenging. Added to this is the controversy of the benefits of DAA compared to other total hip arthroplasty (THA) approaches. Our study aims to assess the influence of experience on learning curve and clinical results when transitioning from THA via posterior approach in a lateral position to DAA in a supine position. Methods: A consecutive retrospective series of 525 total hip arthroplasty of one senior and six junior surgeons was retrospectively analysed from May 2013 to December 2017. Clinical results were analysed and compared between the two groups and represented as a learning curve. Mean follow up was 36.2 months ± 11.8. Results: This study found a significant difference in complications between the senior and junior surgeons for operating time, infection rate, and lateral femoral cutaneous nerve (LFCN) neuropraxia. A trainee’s learning curve was an average of 10 DAA procedures before matching the senior surgeon. Of note, the early complications correlated with intraoperative fractures increased with experience in both groups. Operating time for the senior equalised after 70 cases. Dislocation rate and limb length discrepancy were excellent and did not show a learning curve between the two groups. Conclusion: DAA is a safe approach to implant a THA. There is a learning curve and initial supervision is recommended for both seniors and trainees. Level of evidence: Retrospective, consecutive case series; level IV.

Introduction: Distal Femoral Osteotomy (DFO) is a common procedure for correcting lower limb valgus deformity and lateral compartment overload. Low 20-year survivorship rate was reported with a consequent need for total knee arthroplasty (TKA). This study aims to review literature and to analyse the influence of a previous distal femoral osteotomy on outcomes of patients undergoing TKA. Methods: A systematic literature review was performed in PubMed/Medline and Embase in May 2020. Papers were selected based on the following criteria: patient with a previous distal femoral osteotomy; total knee replacement; Pre- and Postoperative outcomes; surgical outcomes: clinical scores, range of motion, radiographic evaluation and revisions for any cause; case series, retrospective studies, observational studies, open-label studies, randomized clinical trials; systematic reviews and meta-analyses were included to extract primitive studies. Results: 306 articles were found, of which five papers were considered eligible for this review. In every study included, postoperative clinical outcomes (Knee Society Score or Hospital for Special Surgery score) statistically improved from the preoperative. Complications were not uncommon; implant survivorship at the available follow-up seems to be similar to primary TKA, although being too short to draw any conclusions. Conclusions: Limited and highly heterogeneous evidence is currently available on the influence of DFO on outcomes after TKA. Knee replacement improves clinical middle-term outcomes in patients with previous distal femoral osteotomy. In this complex surgery, the use of technical tips and tricks could help surgeons to obtain an accurate knee balancing and better long-term results.

Introduction: The number of total knee replacements performed (TKR) is increasing and so are patient expectations and functional demands. The mean age at which orthopedic surgeons may indicate TKR is decreasing, and therefore return to sport (RTS) after TKR is often an important expectation for patients. The aim of this study was to analyze the mid-term RTS, recreational activities, satisfaction level, and forgotten joint level after TKR. Methods: Between January 2015 and December 2016, 536 TKR (same implant design, same technique) were performed in our center. The mean age at survey was 69 years with a mean follow-up of 43 months. All patients who did not have a follow-up in the last 6 months were called. Finally, 443 TKR were analyzed. RTS was assessed using the University of California Los Angeles Scale (UCLA), forgotten joint score (FJS), and Satisfaction Score. Results: In this study, 85% of patients had RTS after TKR with a mean UCLA score increasing from 4.48 to 5.92 and a high satisfaction rate. Satisfaction with activity level was 93% (satisfied and very satisfied patients). The RTS is more important for people with a higher preoperative UCLA score and a lower American Society of Anesthesiologist score (ASA). Each point increase in ASA score is associated with reduced probability to RTS by 52%. Discussion: RTS and recreational activity were likely after TKR with a high satisfaction score. Preoperative condition and activity are the two most significant predictive factors for RTS. Level of evidence: Retrospective case series, level IV.

Purpose: The aim of this study was to perform a systematic review of the literature to determine whether there are any clinical or radiological differences in mechanically aligned Total Knee Arthroplasty (TKA) compared with kinematically aligned TKA. Methods: This study included retrospective cohort studies, prospective randomized controlled trials (PRCTs) and prospective cohort studies comparing clinical and radiological outcomes, and complications in TKA with kinematic alignment (KA) and mechanical alignment (MA). All studies had a minimum follow-up of 2 years. Results: Five PRCTs published between 2014 and 2020 were included. These studies showed a low risk of bias and were of very high quality. We did not find a superiority of KA compared to MA technique for clinical and radiological outcomes, except in one study which showed a significant difference favoring KA between the two groups for all clinical scores. Conclusion: We found that KA in TKA achieved clinical and radiological results similar to those of MA. The complication rate was not increased for KA TKAs. Studies with longer follow-up and larger cohorts are required to prove any benefit of KA technique over MA technique.

BackgroundPredictive modeling promises to improve our understanding of what variables influence patient satisfaction after total knee arthroplasty (TKA). The purpose of this article was to systematically review the relevant literature using predictive models of clinical outcomes after TKA. The aim was to identify the predictor strategies used for systematic data collection with the highest likelihood of success in predicting clinical outcomes.MethodsA Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol systematic review was conducted using 3 databases (MEDLINE, EMBASE, and PubMed) to identify all clinical studies that had used predictive models or that assessed predictive features for outcomes after TKA between 1996 and 2020. The ROBINS-I tool was used to evaluate the quality of the studies and the risk of bias.ResultsA total of 75 studies were identified of which 48 met our inclusion criteria. Preoperative predictive factors strongly associated with postoperative clinical outcomes were knee pain, knee-specific Patient-Reported Outcome Measure (PROM) scores, and mental health scores. Demographic characteristics, pre-existing comorbidities, and knee alignment had an inconsistent association with outcomes. The outcome measures that correlated best with the predictive models were improvement of PROM scores, pain scores, and patient satisfaction.ConclusionsSeveral algorithms, based on PROM improvement, patient satisfaction, or pain after TKA, have been developed to improve decision-making regarding both indications for surgery and surgical strategy. Functional features such as preoperative pain and PROM scores were highly predictive for clinical outcomes after TKA. Some variables such as demographics data or knee alignment were less strongly correlated with TKA outcomes.Level of evidenceSystematic review - Level III.