Use of dual mobility cup cemented into a tantalum acetabular shell for hip revision with large bone loss can decrease dislocation risk without increasing the risk of mechanical failure.

BACKGROUND: Porous tantalum components and augments have demonstrated short to midterm fixation stability in acetabular total hip arthroplasty (THA) revision but do not offer a novel option to decrease the postoperative dislocation rate. Recently, dual mobility (DM) cups have gained interest to decrease the prevalence of recurrent hip instability after revision hip arthroplasty, but this issue was not confirmed combined with use of tantalum reconstruction devices. Therefore, we did a retrospective study aiming to: (1) evaluate at a 5-year minimum follow-up period the dislocation rate (and other intra- and postoperative complications), (2) assess radiographic results specifically looking at osseointegration and restoration of the hip center, (3) and also clinical results in a cohort of patients who underwent complex acetabular reconstruction with trabecular metal revision components associated with a cemented DM socket. HYPOTHESIS: Using a DM socket cemented in porous tantalum components can reach the low risk of hip dislocation reported with DM components in revision setting without increasing the risk of a mechanical failure. METHODS: A cross-sectional study identified 174 THA revision including an acetabular revision. Were excluded 118 revisions with acetabular defects Type 1, 2a or 2B according to Paprosky's classification, as well as 18 hips revised without a dual mobility and 3 patients (3 hips) lost to follow-up. Were thus included in this study 35 hips (35 patients) implanted with uncemented total hip arthroplasty revision using both trabecular metal acetabular cup-cage reconstruction and a cemented DM cup. Seven hips were classified Paprosky types 2C, 15 type 3A and 13 types 3B. Patients were followed with clinical and radiological evaluation regarding dislocation rate, infection, reoperation or re-revision, osseointegration and restoration of the hip center, and functional results according to the Harris hip score and psoas impingement presence. RESULTS: At a mean follow-up of 8.1±1.8 years (5.1-12.6), one dislocation was recorded, and one acute deep infection. No patient required a cup re-revision for septic or aseptic loosening. The survivorship at 8years regarding revision for any cause as an endpoint was 96.5% (CI95%: 92-99). Osseointegration of TM implants was analyzed and found no acetabular migration at the last follow-up in the cohort. The mean hip center position was optimized from 48±7mm (37-58) to 34±5mm (29-39) vertically and from 26±5mm (-18-36) to 24±8mm (7-31) horizontally without reaching significance (p=0.1). On the last follow-up X-rays, the mean acetabular inclination was 47̊±9̊ (32̊-61̊). According to the criteria of Hirakawa, 97.1% (34/35) of the hip centers were restored. One cup (2.9%) was more than 5mm proximally from the hip center, and none more than 10mm. Clinical results assessed a Harris Hip Score improved from 36±17 (23-62) preoperatively to 82±15 (69-93) at last follow-up (p<0.0001). Two patients (2/35, 5.7%) complained of psoas impingement. CONCLUSION: This study suggests effectiveness of DM cups in association with a tantalum-made acetabular shell for reconstruction of large bone defect in THRs for both solving postoperative instability and aseptic loosening without increasing the re-revision rate for any reason in a midterm follow-up. LEVEL OF EVIDENCE: IV; observational study.

Quick Transition to One Day Length of Stay after Hip and Knee Arthroplasty Using a Digital Follow-Up Tool during COVID-19: A Retrospective Comparative Study.

The COVID-19 pandemic highlighted the need for efficient use of hospital infrastructure. The hypothesis was that a rapid shift to outpatient surgery after hip or knee arthroplasty could be implemented without compromising quality of care. The aim of this study was to assess the safety, pain management and patient-reported outcomes before and after the implementation of an accelerated discharge program using a digital follow-up tool. A retrospective cohort design was used to compare 97 patients who received primary total hip or knee arthroplasty during the pandemic (early discharge) to comparable 194 pre-pandemic patients (normal discharge). Both cohorts had the same inclusion criteria and were closely monitored using the digital follow-up tool. The accelerated discharge program reduced length of stay from a median of 3 days (before the pandemic) to a median of 1 day (during the pandemic) (p < 0.001). The complication rate of 2% was the same for both groups (p > 0.05). Patient-reported outcomes for matched samples of hip (n = 100) and knee (n = 82) arthroplasty patients were similar before, at 6 weeks and 3 months after surgery for both groups (p > 0.05). There were no differences in pain and medication consumption for the first 6 weeks (p > 0.05). This study demonstrates that reducing length of stay from three to one night after total knee or hip arthroplasty, with the help of a digital follow-up tool, results in a stable rate of complications, readmission, and comparable clinical outcomes, while reducing the socio-economic burden on the health system.

The Deep-MCL Line: A Reliable Anatomical Landmark to Optimize the Tibial Cut in UKA.

The extramedullary guides for the tibial resection during medial unicompartmental knee arthroplasty (UKA) are inaccurate, with an error risk in coronal and sagittal planes and cut thickness. It was our hypothesis that the use of anatomical landmarks for the tibial cut can help the surgeon to improve accuracy. The technique described in this paper is based on the use of a simple and reproducible anatomical landmark. This landmark is the line of insertion of the fibers of the deep medial collateral ligament (MCL) around the anterior half of the medial tibial plateau called the "Deep MCL insertion line". The used anatomical landmark determines the orientation (in the coronal and sagittal planes) and the thickness of the tibial cut. This landmark corresponds to the line of insertion of the fibers of the deep MCL around the anterior half of the medial tibial plateau. A consecutive series of patients who underwent primary medial UKA between 2019 and 2021 were retrospectively reviewed. A total of 50 UKA were included. The mean age at the time of surgery was 54.5 ± 6.6 years (44-79). The radiographic measurements showed very good to excellent intra-observer and inter-observer agreements. The limb and implant alignments and the tibial positioning were satisfying, with a low rate of outliers and good restoration of the native anatomy. The landmark of the insertion of deep MCL constitutes a reliable and reproducible reference for the tibial cut axis and thickness during medial UKA, independent of the wear severity.

Retrospective analysis of return to impact sport after medial unicompartmental knee arthroplasty based on a cohort of 92 patients.

BACKGROUND: Return to sport after Knee Arthroplasty has been investigated reporting modifications in the physical activities with a trend towards to lower impact sports after Unicompartemental Knee Arthroplasty. The purpose of this study was to analyze the return to sport level after medial unicompartmental knee arthroplasty (MUKA) in a population of osteoarthritic patients having practiced impact sport, defined with a University of California at Los Angeles activity scale (UCLA)≥9 in their pre-symptomatic arthritic period. HYPOTHESIS: Return to an impact sport after MUKA was possible for a population of osteoarthritic patients having practiced impact sport in their pre-symptomatic arthritic period. METHODS: Ninety-two MUKA with a pre-symptomatic arthritic UCLA score≥9, including 60 men (65.2%) and operated between January 2009 and September 2014, were evaluated by a dedicated survey. Informations were obtained concerning the physical activities (intensity, frequency, kind of sport, reasons to decrease or stop the physical activities in the pre- and the postoperative period). The average age was 64.9 years±6.4 (range 49-74.4). Three different periods were compared: pre-symptomatic arthritic, preoperative and postoperative period. The mean follow-up was 7.3±1.7 years. RESULTS: The mean pre-symptomatic arthritic UCLA score was 9.9±0.3, the mean preoperative UCLA score was 7.0±2.5 (2-10) and the mean postoperative UCLA score was 7.2±2.0 (3-10). There were significant differences for the mean UCLA score values between pre-symptomatic arthritis and postoperative UCLA scores (p=0.034), however no difference was detected in mean score values before and after surgery (p=0.09). Only 32.6% (30/92) of patients had a postoperative UCLA score≥9. For patients practicing an impact sport activity (UCLA≥9) in the preoperative period (23/92; 25%), the postoperative UCLA score was at 8±1.1 (range 4-10). In this subgroup, 47.8% (11/23) of patients had a postoperative UCLA score≥9. The decline in sports in postoperative was predominantly explained by residual pain of the operated knee (31/92; 34%), precaution to not damage the prosthesis (25/92; 27%) and restrictions due to another joint (19/92; 21%). DISCUSSION: Return to impact sport after MUKA seems to be limited to a restrained number of patients. The main reasons to the decline in sporting activity level are linked to the residual pain of the operated knee and the precaution to not damage the prosthesis. LEVEL OF EVIDENCE: IV, retrospective cohort study.

Is sequential bilateral robotic total knee arthroplasty a safe procedure? A matched comparative pilot study.

INTRODUCTION: To our knowledge, no papers have reported the results of robotic-assisted surgery for sequential bilateral Total Knee Arthroplasty (TKA). Indeed, sequential bilateral TKA present several benefits, as one single anesthesia, surgical episode, hospitalization, and rehabilitation. The purpose of our study was to evaluate peri-operative outcomes and compare the complication rates, clinical outcomes, and implant positioning of sequential bilateral TKA performed with a robotic-assisted system versus a conventional technique. MATERIALS AND METHODS: All patients who underwent a sequential bilateral robotic-assisted primary TKA (raTKA) in our institution between November 2019 and February 2021 were included. Twenty patients met the inclusion criteria and were matched with 20 sequential bilateral TKA performed with a conventional technique. The two groups were comparable for the demographic data and the preoperative parameters, including preoperative anticoagulation and ASA score. The minimum follow-up was 6 months. RESULTS: The operative time was significantly longer in the robotic group (< 0.0001), with a mean additional time of 29 min. There was no significant difference between both groups for postoperative blood loss, rate of blood transfusion, or postoperative pain. The average length of stay was 5 days. There was one early complication in the robotic group due to the tibial trackers. The functional outcomes were similar between both groups, except for the functional KSS score, which was better at 6 months in the robotic group (p < 0.0001). The restoration of the knee alignment and the distal femoral anatomy were significantly better in the robotic group than in the conventional group. CONCLUSIONS: Despite a longer operative time, the peri-operative parameters of sequential bilateral TKA were similar between robotic and conventional techniques. Further, sequential bilateral raTKA was at least as safe as a conventional technique, without additional risk of medical complications.

An anatomo-functional implant positioning technique with robotic assistance for primary TKA allows the restoration of the native knee alignment and a natural functional ligament pattern, with a faster recovery at 6 months compared to an adjusted mechanical technique.

PURPOSE: An anatomo-functional implant positioning (AFIP) technique in total knee arthroplasty (TKA) could restore physiological ligament balance (symmetric gap in extension, asymmetric gap in flexion). The purposes were to compare (1) ligament balancing in extension and flexion after TKA in the AFIP group, (2) TKA alignment, implant positioning and patellar tracking between AFIP and adjusted mechanical alignment (aMA) techniques, (3) clinical outcomes between both groups at 12 months. METHODS: All robotic-assisted TKA with an AFIP technique were included (n = 40). Exclusion criteria were genu valgum (HKA angle > 183°), extra-articular deformity more than 10°, and patellar maltracking (high-grade J-sign). One control patient with a TKA implanted by an aMA technique was matched for each case, based on age, body mass index, sex, and knee alignment. Ligament balancing (medial and lateral gaps in millimeters) in full extension and at 90° of flexion after TKA in the AFIP group was assessed with the robotic system. TKA alignment (HKA angle), implants positioning (femoral and tibial coronal axis, tibial slope, joint-line orientation), patellar tracking (patellar tilt and translation) and the Knee Society Score (KSS) at 6 and 12 months were compared between both groups. The ligament balancing was compared using a t test for paired samples in the AFIP group. The radiographic measurements and KSS scores were compared between groups using a t test for independent samples. RESULTS: In the AFIP group, there was no significant difference between the medial and lateral gap laxity in extension (NS). A significant opening of the lateral gap was observed in flexion compared to extension (mean: + 2.9 mm; p < 0.0001). The mean postoperative HKA angle was comparable between both groups (177.3° ± 2.1 in the AFIP group vs 176.8° ± 3.2; NS). In the AFIP group, the femoral anatomy was restored (90.9° ± 1.6) and the tibial varus was partially corrected (87.4° ± 1.8). The improvement of Knee and Function KSS at 6 months was better in the AFIP group (59.3 ± 11.9 and 51.7 ± 20, respectively, versus 49.3 ± 9.7 and 20.8 ± 13; p < 0.001). CONCLUSION: The AFIP concept allowed the restoration of the native knee alignment and a natural functional ligament pattern. With a more physiological target for ligament balancing, the AFIP technique had equivalent clinical outcomes at 12 months compared to aMA, with a faster recovery. LEVEL OF EVIDENCE: III retrospective therapeutic case control series.

Safe and reliable clinical outcomes at 2 years of a fixed-bearing partial knee arthroplasty with a morphometric tibial tray in a large worldwide population.

PURPOSE: The purpose of this study was to evaluate: (1) improvement of functional and quality of life scores, (2) adverse events, (3) short-term implants survivorship of a newly designed fixed-bearing partial knee replacement (PKR) with a morphometric tibial tray in a large and multicentric population at a minimum follow-up of 2 years. METHODS: From 2017 to 2019, 479 medial PKR were implanted by 16 non-developing surgeons from United States, Europe, and Japan. Eight patients were lost to follow-up (1.8%). Standardized follow-up procedures included patient-reported outcomes (Oxford Knee Society score, Forgotten Joint Score, EQ VAS, EQ 5D), patient satisfaction, radiographic assessments, adverse event at 2 years. Comparisons between the preoperative and postoperative values were performed using Student t test. Kaplan-Meier survivorship analysis was performed with knee revision as the endpoint. RESULTS: The mean age was 65.6 ± 9.6 years. Mean body mass index was 29.5 ± 5.1 kg/m2. Oxford Knee Society score and Forgotten Joint Score, respectively, improved from 23.7 ± 8 and 16 ± 15.8 preoperatively to 42.4 ± 6.5 and 74 ± 24.9 at 2 years (p < 0.0001). Satisfaction Score was 92.3 ± 13.4 at 2 years. Ten re-operations (2.1%) were reported including seven implant removals (1.5%). No other adverse event was reported. The causes of conversion to total knee arthroplasty were: nickel allergy (n = 2), patellofemoral osteoarthritis (n = 1), pain (n = 1), deep infection (n = 3). Two re-operations were performed due to infection, and one for internal fixation for a tibial plateau fracture. The 2-year Kaplan-Meier survival estimate was 98.4%, with implant removals as the endpoint. CONCLUSION: This prospective multicentric study reported safe and reliable clinical outcomes of a morphometric PKR, which optimized tibial coverage and femoral fit, in a large population of patients worldwide at 2 years. LEVEL OF EVIDENCE: Prospective cohort study-therapeutic study, Level II.

An orthopaedic intelligence application successfully integrates data from a smartphone-based care management platform and a robotic knee system using a commercial database.

PURPOSE: To evaluate the feasibility of using a smartphone-based care management platform (sbCMP) and robotic-assisted total knee arthroplasty (raTKA) to collect data throughout the episode-of-care and assess if intra-operative measures of soft tissue laxity in raTKA were associated with post-operative outcomes. METHODS: A secondary data analysis of 131 patients in a commercial database who underwent raTKA was performed. Pre-operative through six week post-operative step counts and KOOS JR scores were collected and cross-referenced with intra-operative laxity measures. A Kruskal-Wallis test or a Wilcoxon sign-rank was used to assess outcomes. RESULTS: There were higher step counts at six weeks post-operatively in knees with increased laxity in both the lateral compartment in extension and medial compartment in flexion (p < 0.05). Knees balanced in flexion within < 0.5 mm had higher KOOS JR scores at six weeks post-operative (p = 0.034) compared to knees balanced within 0.5-1.5 mm. CONCLUSION: A smartphone-based care management platform can be integrated with raTKA to passively collect data throughout the episode-of-care. Associations between intra-operative decisions regarding laxity and post-operative outcomes were identified. However, more robust analysis is needed to evaluate these associations and ensure clinical relevance to guide machine learning algorithms.

Artificial intelligence in knee arthroplasty: current concept of the available clinical applications.

BACKGROUND: Artificial intelligence (AI) is defined as the study of algorithms that allow machines to reason and perform cognitive functions such as problem-solving, objects, images, word recognition, and decision-making. This study aimed to review the published articles and the comprehensive clinical relevance of AI-based tools used before, during, and after knee arthroplasty. METHODS: The search was conducted through PubMed, EMBASE, and MEDLINE databases from 2000 to 2021 using the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocol (PRISMA). RESULTS: A total of 731 potential articles were reviewed, and 132 were included based on the inclusion criteria and exclusion criteria. Some steps of the knee arthroplasty procedure were assisted and improved by using AI-based tools. Before surgery, machine learning was used to aid surgeons in optimizing decision-making. During surgery, the robotic-assisted systems improved the accuracy of knee alignment, implant positioning, and ligamentous balance. After surgery, remote patient monitoring platforms helped to capture patients' functional data. CONCLUSION: In knee arthroplasty, the AI-based tools improve the decision-making process, surgical planning, accuracy, and repeatability of surgical procedures.

Assistive technologies in knee arthroplasty: fashion or evolution? Rate of publications and national registries prove the Scott Parabola wrong.

PURPOSE: Most opponents of assistive technologies in orthopedic surgery consider them as a marketing ruse or fashion. Our hypothesis was that many innovations in modern knee arthroplasty are not following the Scott Parabola. This parabola represents the visual curve of a procedure or therapy showing great promise at the beginning, becoming the standard treatment after reports of encouraging results, only to fall into disuse due to adverse outcome reports. This study aimed to assess the interest in these assistive technologies by (1) their number of publications/year and (2) their actual surgical use reported in the National Joint Registries. METHODS: The search was performed through PubMed, EMBASE, and MEDLINE databases from 1997 to 2021 inclusive to identify all available literature that described the use and results of assistive technologies or new surgical techniques in knee arthroplasty. In the Australian and Norwegian registries, the number of cases performed with these techniques in knee arthroplasty has been quantified year by year. RESULTS: Following the initial online search, a total of 4085 articles was found. After the assessment mentioned above, 2106 articles were included in the study. The orthopedic techniques assessed in this study are not following the "Scott's parabola" in the literature. Computer-assisted knee arthroplasty and patient-specific instrumentation have increased quickly to have reached a plateau, with a stable number of publications over the last 6 years. The number of publications concerning robotic surgery, accelerometers and sensors continue to rise. In the Australian registry, the proportion of primary TKA performed by computer-assisted systems increased from 2.4% in 2003 to 32% in 2019. In the Norwegian registry, the proportion of computer-assisted TKA remained between 8 and 12% of primary TKA since 2007. CONCLUSION: Most of the innovations in modern knee arthroplasty are not following the Scott Parabola. After a fast rise, these techniques do not disappear but continue to evolve. Their evolution is synergistic, and techniques appeared to be linked to each other's. Despite persisting concerns about the cost-efficiency of assisting technologies in knee arthroplasties, the interest and use do not decrease and seems to be directly linked to an exponential increase in interest for a better understanding of alignment targets and improved functional recovery.

Concepts and techniques of a new robotically assisted technique for total knee arthroplasty: the ROSA knee system.

INTRODUCTION: The ROSA (Robotic Surgical Assistant) Knee system (Zimmer Biomet, Warsaw, IN) for total knee arthroplasty (TKA) can be considered as collaborative robotics, where the surgeon remains in charge of the procedure and collaborates with a smart robotic tool, to perform the surgery with a high accuracy and reproducibility. The aim was to describe: (1) its concept and surgical technique; (2) its advantages and potential limits; (3) the early experience with this system. MATERIALS AND METHODS: The goal during its development phase was to keep the surgeon active and at the center of the operation: the surgeon handles the saw and performs the cuts while the robotic arm places and holds the guide at the right place. The ROSA knee platform assists the surgeon for the distal femoral cut, the femoral component sizing and positioning, the tibial cut and the ligament balance. This robotic system has two options: image-based with 3D virtual model; or image-less, based on intraoperative landmarks acquisition. All the classic surgical techniques can be used: measured resection, gap balancing, functional alignment, kinematic alignment. Some techniques recently developed are more ROSA-specific: Robotic personalized TKA, ROSA-FuZion technique. RESULTS: Its advantages as compared to other available systems include: radiographs in standing position, collaborative robotic system where the robot completes the surgeon skills, "off-the-shelf" implants, predictive robotic with concept of machine learning incorporated into the system. Two cadaveric studies have reported the high accuracy and reproducibility of this device. This robotic system is recent and currently no clinical series has enough follow-up to report clinical outcomes. CONCLUSION: The ROSA knee system is a robotically assisted semi-autonomous surgical system with some specific characteristics. The aim of this collaborative robotic system is to improve the accuracy and reliability of the bone resections and the ligament balancing, without replacing the steps well performed by the surgeon.

Incidence and Risk Factors for Residual High-Grade Pivot Shift After ACL Reconstruction With or Without a Lateral Extra-articular Tenodesis.

BACKGROUND: Residual rotatory knee laxity at midterm follow-up after isolated anterior cruciate ligament reconstruction (ACLR) versus ACLR with lateral extra-articular tenodesis (LET) remains an issue. PURPOSE/HYPOTHESIS: To evaluate the outcomes of ACLR with or without additional LET at a minimum 2-year follow-up in patients with preoperative high-grade pivot shift (PS). Our hypothesis was that the addition of LET would decrease the risk of secondary meniscal injury and the presence of residual high-grade PS at follow-up. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A retrospective analysis performed at 3 sports medicine centers identified 266 study patients; all had a high-grade PS (grade 2 or 3) preoperatively and underwent isolated ACLR with or without LET. Four different ACLR techniques were used: single-strand quadrupled semitendinosus (ST4) ACLR without LET (ST4 group; n = 55), ST4 with anatomic LET (ST4+LET group; n = 77), bone-patellar tendon and modified Lemaire LET (BTB+LET group; n = 43), and quadriceps tendon and modified Lemaire LET (QT+LET group; n = 91). At follow-up, we evaluated for the presence of high-grade (grade ≥2) PS. Preoperative meniscal tears and their treatment were recorded. RESULTS: Overall, 185 (69.5%) patients had at least 1 meniscal tear at index surgery. The mean follow-up period was 44.3 months; 47 (17.7%) patients had a new meniscal tear and 64 (24%) patients had a high-grade PS at follow-up. Compared with meniscal repair, significant predictors for high-grade PS at follow-up were meniscectomy (odds ratio [OR] = 2.65 [95% CI, 1.19-5.63]; P = .02) and nonrepair of preoperative meniscal tear (OR = 3.26 [95% CI, 1.27-9.43]; P = .007). The appearance of a new symptomatic meniscal tear was the strongest significant predictor of high-grade PS at follow-up (OR = 4.31 [95% CI, 2.31-8.06]; P < .001). No significant correlation was observed between the addition of LET and the presence of high-grade PS at follow-up. CONCLUSION: In the current study, 1 in 4 patients with high-grade PS before ACLR with or without LET was at risk of residual rotatory knee laxity at mean 44-month follow-up, regardless of the technique used. Repairing a pre-existing meniscal lesion was more effective than performing LET to decrease the presence of a high-grade PS at follow-up.

Neutral alignment resulting from tibial vara and opposite femoral valgus is the main morphologic pattern in healthy middle-aged patients: an exploration of a 3D-CT database.

PURPOSE: Given the goal of achieving optimal correction and alignment after knee arthroplasty or high tibial osteotomy, literature focusing on the inter-individual variability of the native knee, tibia and femur with regards to the coronal or sagittal alignment is lacking. The aim of this study was to analyse normal angular values in the healthy middle-aged population and determine differences of angular values according to inter-individual features. The first hypothesis was that common morphological patterns may be identified in the healthy middle-aged non-osteoarthritic population. The second hypothesis was that high inter-individual variability exists with regards to gender, ethnicity and alignment phenotype. METHODS: A CT scan-based modelling and analysis system was used to examine the lower limb of 758 normal healthy patients (390 men, 368 women; mean age 58.5 ± 16.4 years) with available data concerning angular values and retrieved from the SOMA database. The hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA) and non weight-bearing joint line convergence angle (nwJLCA) were then measured for each patient. Results were analysed for the entire cohort and based on gender, ethnicity and phenotype. RESULTS: The mean HKA was 179.4° ± 2.6°, LDFA: 85.8° ± 2.0°, MPTA: 85.6° ± 2.4°, PDFA: 85.2° ± 1.5°, PPTA: 83.8° ± 2.9° and nwJLCA: 1.09° ± 0.9°. Gender was associated with higher LDFA and lower HKA for men. Ethnicity was associated with greater proximal tibial vara and distal femoral valgus for Asian patients. Patients with an overall global varus alignment had more tibia vara and less femoral valgus than patients with an overall valgus alignment. CONCLUSION: Even if significant differences were found based on subgroup analysis (gender, ethnicity or phenotype), this study demonstrated that neutral alignment is the main morphological pattern in the healthy middle-aged population. This neutrality is the result from tibia vara compensated by an ipsilateral femoral valgus. LEVEL OF CLINICAL EVIDENCE: III, retrospective cohort study.

Trabecular Metal Cones Combined With Short Cemented Stem Allow Favorable Outcomes in Aseptic Revision Total Knee Arthroplasty.

BACKGROUND: The purpose of this study was to compare the functional outcomes and implant survivorship at a minimum of 5 years of follow-up of several reconstruction techniques with or without metaphyseal cone and stems of variable length. METHODS: A retrospective comparative matched analysis was performed from 2 prospectively collected databases. Only patients who underwent revision total knee arthroplasty procedures for aseptic causes using a single design of rotating hinge knee with a minimum of 5 years of follow-up were analyzed. Patients were separated into 3 groups: trabecular metal (TM) cones + short cemented stems (TM + short stem [SS]), TM cones + long uncemented stems (TM + long stem [LS]), and no cone (NC) + long uncemented stems (NC + LS). A matching process based on age (±5 years) was realized. RESULTS: About 99 patients were included; 33 in the TM + SS group, 33 in the TM + LS group, and 33 in the NC + LS group. The mean time of follow-up was 9.3 years. A significant difference of the improvement of subscale pain, symptom, activities of daily living, quality of life of the Knee Injury and Osteoarthritis Outcome score and knee, function of the Knee Society Score was observed in favor of TM + SS group compared with the 2 other groups. At 8 years of survivorship, the components free of revision for any cause were 90.9% for the TM + SS group, 84.9% for the TM + LS group, and 90.6% for the NC + LS group. CONCLUSION: The use of a short cemented tibial stem combined with a TM cone in revision total knee arthroplasty offers identical survival rate with better functional outcome compared with the use of a long uncemented stem associated with TM cones or metallic augments at a minimum of 5 years of follow-up.

Can dual mobility cups prevent dislocation without increasing revision rates in primary total hip arthroplasty? A systematic review.

BACKGROUND: Dislocation is one of the leading causes for early revision surgery after total hip arthroplasty (THA). To address this problem, the dual mobility (DM) cup was developed in the 1970s by the French. Despite the increased and, in some countries, broad use of DM cups, high quality evidence of their effectiveness compared to traditional unipolar (UP) cups is lacking. There are a few well-conducted literature reviews, but the level of evidence of the included studies was moderate to low and the rates of revision were not specifically investigated. Therefore, we did a systematic review to investigate whether there is a difference in the rate of dislocations and revisions after primary THA with a DM cup or a UP cup. METHODS: We conducted a systematic literature search in PubMed, Embase and Cochrane databases in July 2019. The articles were selected based upon their quality, relevance and measurement of the predictive factor. We used the MINORS criteria to determine the methodological quality of all studies. RESULTS: The initial search resulted in 702 citations. After application of the inclusion and exclusion criteria, eight articles met our eligibility criteria and were graded. Included studies were of medium to low methodological quality with a mean score of 14/24 (11-16) points following the MINORS criteria. In the case-control studies, a total of 549 DM cups and 649 UP cups were included. In the registry studies, a total of 5.935 DM cups and 217.362 UP cups were included. In the case-control studies, one (0.2%) dislocation was reported for the DM cups and 46 (7.1%) for the UP cup (p=0.009, IQR=0.00-7.00). Nine (1.6%) revisions, of which zero due to dislocation, were reported for the DM cup and 39 (6.0%), of which 30 due to dislocation, for the UP cup (p=0.046, CI=-16.93-5.73). In the registry studies 161 (2.7%) revisions were reported for the DM cup, of which 14 (8.7%) due to dislocation. For the UP cup, 3.332 (1.5%) revisions were reported (p=0.275, IQR=41.00-866.25), of which 1.093 (32.8%) due to dislocation (p=0.050, IQR=3.50-293.25). CONCLUSION: This review suggests lower rates of dislocation and lower rates of revision for dislocation in favor of the DM cups. Concluding, DM cups might be an effective solution to reduce dislocation in primary THA. To evaluate the efficacy of DM cups compared to UP cups, an economic evaluation alongside a randomized controlled trial is needed focusing on patient important endpoints. LEVEL OF EVIDENCE: III, systematic review of level III studies.

Opening wedge high tibial osteotomy allows better outcomes than unicompartmental knee arthroplasty in patients expecting to return to impact sports.

PURPOSE: Prior studies have compared unicompartmental knee arthroplasty (UKA) with high tibial osteotomy (HTO) suggesting that both procedures had good functional outcomes. But none had established the superiority of one of the two procedures for patients with high expectation including return to impact sport. The aim of this study was to compare functional outcomes and ability to return to impact sport of active patients defined with a pre-arthritis University of California and Los Angeles activity (UCLA) score > 8, after UKA or HTO procedures. METHODS: A retrospective review of patients with a pre-arthritis UCLA score > 8 operated between January 2014 and September 2017 has identified 91 patients with open-wedge HTO and 117 patients with UKA. A matching process based on age (± 3 years) and gender allowed to include 50 patients in each group for comparative analysis. Patient reported outcomes included Knee Osteoarthritis Outcomes Score (KOOS), UCLA Score, Knee Society Score (KSS) and time to return to sport or previous professional activities at 3, 6, 12 and 24 months following surgery. RESULTS: Mean time to return to sport activities or previous professional activities were significantly lower for the HTO group than for UKA group [respectively, 4.9 ± 2.2 months for HTO group vs 5.8 ± 6.2 months for UKA group (p = 0.006) and 3 ± 3 months for HTO group vs 4 ± 3 months for UKA group (p = 0.006)]. At 24-month follow-up, UCLA score, KOOS Sports Sub-score and KSS activity score were significantly higher for HTO group than for UKA group (Δ: 2 CI 95% (1.3-2.5 points) p < 0.0001, (Δ: 10.9 CI 95% (2.9-18.9 points) p = 0.04 and Δ: 7.8 CI 95% (2.4-13.4 points) p = 0.006, respectively) and 31 patients (62%) were practicing impact sport in the HTO group versus 14 (28%) in the UKA group (odd-ratio 4.2 CI 95% (1.8-9.7) p < 0.0001). CONCLUSION: HTO offers statistically significant quicker return to sport activities and previous professional activities with a higher rate of patients able to practice impact activity (62% for HTO vs 28% for UKA) and better sports related functional scores at two years after surgery compared to UKA. LEVEL OF EVIDENCE: III retrospective case-control study.

Patient-specific high-tibial osteotomy's 'cutting-guides' decrease operating time and the number of fluoroscopic images taken after a Brief Learning Curve.

PURPOSE: Patient-specific cutting guides (PSCGs) have been advocated to improve the accuracy of deformity correction in opening-wedge high-tibial osteotomies (HTO). It was hypothesized that PSCGs for HTO would have a short learning curve. Therefore, the goals of this study were to determine the surgeons learning curve for PSCGs used for opening-wedge HTO assessing: the operating time, surgeons comfort levels, number of fluoroscopic images, accuracy of post-operative limb alignment and functional outcomes. METHODS: This prospective cohort study included 71 consecutive opening-wedge HTO with PSCGs performed by three different surgeons with different experiences. The operating time, the surgeon's anxiety levels evaluated using the Spielberger State-Trait Anxiety Inventory (STAI), the number of fluoroscopic images was systematically and prospectively collected. The accuracy of the postoperative alignment was defined by the difference between the preoperative targeted correction and the final post-operative correction both measured on standardized CT-scans using the same protocol (ΔHKA, ΔMPTA, ΔPPTA). Functional outcomes were evaluated at 1 year using the different sub-scores of the KOOS. Cumulative summation (CUSUM) analyses were used to assess learning curves. RESULTS: The use of PSCGs in HTO surgery was associated with a learning curve of 10 cases to optimize operative time (mean operative time 26.3 min ± 8.8), 8 cases to lessen surgeon anxiety levels, and 9 cases to decrease the number of fluoroscopic images to an average of 4.3 ± 1.2. Cumulative PSCGs experience did not affect accuracy of post-operative limb alignment with a mean: ΔHKA = 1.0° ± 1.0°, ΔMPTA = 0.5° ± 0.6° and ΔPPTA = 0.4° ± 0.8°. No significant difference was observed between the three surgeons for these three parameters. There was no statistical correlation between the number of procedures performed and the patient's functional outcomes. CONCLUSION: The use of PSCGs requires a short learning curve to optimize operating time, reduce the use of fluoroscopy and lessen surgeon's anxiety levels. Additionally, this learning phase does not affect the accuracy of the postoperative correction and the functional results at 1 year. LEVEL OF EVIDENCE: II: prospective observational study.

Adding a protective K-wire during opening high tibial osteotomy increases lateral hinge resistance to fracture.

PURPOSE: It was hypothesized in this in-vitro study that positioning a K-wire intersecting the cutting plane at the theoretical lateral hinge location would limit the cut depth and help preserve the lateral hinge during the opening of the osteotomy. Objectives were (1) to compare the mechanical resistance of the hinge and the protective effect of leaving the K-wire during the opening procedure (2) to check if the K-wire would limit the depth of the osteotomy. METHODS: An ex-vivo mechanical study, testing 5 pairs of fresh-frozen tibias, was designed. CT-scan based Patient-specific cutting guides were obtained to define the cutting plane and the location of the K-wire at the hinge, using standardized 3D planning protocol. In each pair, OWHTO was performed either with or without the K-wire. To evaluate the hinge's resistance to fracture, the specimens were rigidly fixed at the proximal tibia and a direct load was applied on the free tibial diaphysis to open the osteotomy. The maximum load at breakage, maximum permissible displacement and maximal angulation of the osteotomy before hinge failure was measured. To assess the preservation of an unscathed hinge (protected by the K-wire), the distance from the end of the osteotomy cut to the lateral tibial cortical was measured in mm. RESULTS: The maximum load to hinge breakage in the K-wires PsCG knees compared to the control group (48.3 N vs 5.5 N, p = 0.004), the maximum permissible displacement (19.8 mm vs 7.5 mm, p = 0.005) and the maximal angulation of the osteotomy before hinge breakage (9.9° vs 2.9°, p = 0.002) were all statistically superior in the K-wires PsCG knees compared to the control group. A mean distance of 10 ± 1 mm between cut-bone (saw-print) and lateral hinge cortical bone was found post-performing the osteotomy and the hinge failing. CONCLUSION: The maximum load to breakage and the maximum permissible displacement were, respectively, 880% and 260% higher during the opening of the OWHTO in using K-wires compared to the non-K-wire control group. This confirms the mechanical advantage of using a K-wire for both stabilization and protecting the Hinge during OWHTO. This comparative cadaveric study shows an improvement of the lateral hinges resistance to failing during the opening of the osteotomy. This can be achieved by the placement of a K-wire intersecting the cutting plane at the theoretical location of the lateral hinge.

A protective hinge wire, intersecting the osteotomy plane, can reduce the occurrence of perioperative hinge fractures in medial opening wedge osteotomy.

PURPOSE: A recent study reported that positioning a K-wire to intersect the cutting plane at the theoretical lateral hinge location increases the lateral hinge's resistance to fracture during the opening of opening wedge high tibial osteotomy (OWHTO). The purpose of this study was to evaluate the clinical relevance of the use of this K-wire and its benefits in terms of lateral hinge protection during OWHTO in daily practice. METHODS: A retrospective comparative study identified 206 patients who underwent OWHTO from January 2014 to December 2017. Among these patients, 71 had an additional K-wire (HK + group), whereas 135 did not (HK- group). The subjects meeting the inclusion criteria were included in a matched pairing process, which identified 60 patients in the HK + group and 60 patients in the HK- group. Mean follow-up time was 2.3 ± 1.0 years (range 2-4.2). Radiographic outcomes were evaluated with intraoperative and postoperative fluoroscopic imaging and with CT imaging at 6 weeks post OWHTO surgery. The knee osteoarthritis outcomes score (KOOS) was used and time needed to return to work and any kind of sports was collected. RESULTS: Thirty six patients (30%) were found to have a LHF. Among these patients, 26 (72%) did not have an additional K-wire positioned at their theoretical lateral hinge location (HK- group) during the procedure. LHF rate for patients without additional K-wire group (HK-) was 43.3%, whereas it was 16.7% for the patients with an additional K-wire (HK +) [Odd ratio 3.8 95% CI 1.6-8.3; p = 0.005]. The mean time to return to work, return to any kind of sports, and bone union was significantly shorter for HK + group (p < 0.05). CONCLUSION: This study demonstrated that during OWHTO, positioning a K-wire intersecting the cutting plane at the theoretical lateral hinge location reduced the number of intraoperative lateral hinge fractures. LEVEL OF EVIDENCE: III retrospective case-control study.

Non-operative treatment is a reliable option in over two thirds of patients with Garden I hip fractures. Rates and risk factors for failure in 298 patients.

BACKGROUND: Non-operative treatment for impacted femoral neck fractures is a now rarely used strategy whose indications are controversial. No outcome predictors have been convincingly identified, in part due to the small sizes of available studies. We conducted a large retrospective study with the following objectives: (1) to evaluate the percentage of patients older than 65 years of age with non-operatively treated Garden I femoral neck fractures who experience secondary displacement, (2) to identify predictors of secondary displacement, and (3) to determine the frequency of non-operative treatment failure due to any cause and requiring joint replacement surgery. HYPOTHESIS: Non-operative treatment is reliable in patients older than 65 years of age with Garden I femoral neck fractures. MATERIAL AND METHODS: Approval was obtained from the French data protection authority to conduct a retrospective observational study of information in the Marseille university hospitals database. Consecutive patients who were older than 65 years of age at traumatology department admission for Garden I femoral neck fractures managed non-operatively between January 2007 and December 2017 were included. Non-operative treatment consisted in a walking test on day 1 followed by radiographs on days 2, 7, 14, 21, and 45 and after 3 and 12 months. Patients with secondary displacement underwent hip arthroplasty. Demographic data, cognitive performance, and radiological parameters were collected for each patient. We evaluated the rates of secondary displacement avascular necrosis, and non-union. RESULTS: We included 298 patients with a mean age of 82 years (range, 65-101). Mean follow-up was 5±3 years. Secondary displacement occurred in 91 (30%) patients, at a mean of 16 days (range 2-45 days) after the fracture. Avascular necrosis of the femoral head developed in 13 (4.3%) patients and non-union in 11 (3.7%) patients. Secondary displacement was significantly associated with hypnotic treatment (OR, 4.1; 95%CI, 2.2-7.5; p=0.039), institutionalisation (OR, 6.7; 95%CI, 3.1-14.8; p=0.028), a history of repeated falls (OR, 13.5; 95%CI, 6.3-8.4; p<0.0001), having three or more comorbidities (OR, 3.2; 95%CI, 1.7-5.8; p=0.046), and having dementia (OR, 3.5; 95%CI, 1.7-6.9; p=0.0003). Secondary displacement occurred in 18 (12%) of the 151 community-dwelling patients with normal cognition and no history of repeated falls compared to 37 (75%) of the 50 institutionalised patients with dementia. DISCUSSION: Non-operative treatment was effective in 196 (66%) of 298 patients with Garden I femoral neck fractures. Significant risk factors for secondary displacement were dementia, institutionalisation, hypnotic treatment, multiple comorbidities, and a history of repeated falls. Of 151 community-dwelling patients with normal cognition and no repeated falls, 133 (88%) achieved a full recovery with non-operative treatment alone. LEVEL OF EVIDENCE: IV, retrospective cohort study.