After MPFL reconstruction, femoral tunnel widening and migration increase with poor tunnel positioning and are related to poor clinical outcomes.

PURPOSE: Isolated MPFL reconstruction (iMPFLR) is increasingly used for the surgical treatment of treatment for recurrent patella dislocation. The purpose of this study was to evaluate the influence of tunnel widening and migration on clinical outcomes after iMPFL using a CT-scannographic analysis at 6 months postoperatively. METHODS: One hundred and sixty patients (91 females for 69 males) with an average age of 23 years [14-54] who underwent iMPFLR and had an evaluation scan at 6 months postoperatively were evaluated with a mean follow-up of 97 ± 89 months [12 to 166]. Functional International Knee Documentation Committee (IKDC) Score, Kujala score, and joint mobility were assessed preoperatively, at 6 months and at the latest follow-up. The IKDC and Kujala scores were expressed as the difference between pre- and postoperative scores (dIKDC and dKujala). The position of the femoral tunnel was assessed according to the Schöttle criteria on post-operative radiographic profiles. Tunnel widening (at three levels of measurement) and the migration of the center of the tunnel were studied on a CT-scan analysis at 6 months. Any correlation and regression between the evolution of the clinical scores and the measured scannographic parameters were investigated. The relationships between tunnel position and tunnel changes were also studied. RESULTS: Between pre- and post-op, the IKDC (45 ± 13 to 80 ± 15, p < 0.001) and Kujala (55 ± 11 to 87 ± 12, p < 0.001) scores were significantly improved. Patients with tunnel changes had decreased clinical and functional results at 6 months post-op of an iMPFLR (p < 0.001). These changes in the femoral tunnel, evidenced by a tunnel entrance widening and migration of the tunnel center, were related to an initial malposition of the tunnel (p < 0.001). CONCLUSION: In iMPFLR, changes in the femoral tunnel, corresponding to dilatation and migration of the tunnel center, may occur. These changes are increased by the initial malpositioning of the femoral tunnel and are correlated with less good clinical and functional outcomes. LEVEL OF EVIDENCE: Level IV.

What Are the Sonographic Outcomes of Acute Achilles Tendon Rupture? Nonoperative Versus Surgical Repair?

INTRODUCTION: The objective was to compare the two-year ultrasonographic outcomes in a consecutive series of patients with acute Achilles tendon rupture (ATr), either treated surgically or nonoperatively. MATERIALS AND METHODS: This is a prospective, single-center, consecutive series. All patients presenting with acute ATr were included and divided into two groups: surgical or nonoperative groups. At two years, patients were evaluated clinically and sonographically. The parameters studied were length of the tendon on the rupture side (LTCR) and on the contralateral side (LTCS), ratio LTCR/LTCS, maximum anteroposterior diameter on the rupture side (DAPMR), maximum surface area on the rupture side (SMR), maximum anteroposterior diameter on the contralateral side (DAPMS), and maximum surface area on the contralateral side (SMS). Morphological changes in tendon structure were reported. RESULTS: Thirty patients were included. No difference in functional score was observed between both groups. In the nonoperative group, there is a significant difference between: LTCR and LTCS; DAPMR and DAPMS. In the surgical group, there is a significant difference between: LTCR and LTCS; DAPMR and DAPMS; SMR and SMS. There is a significant difference when comparing SMR/SMS between both groups. In terms of morphological changes in tendon structure, there were differences. CONCLUSION: At two years, there was no difference in functional outcomes between the two groups. In both groups, AT were lengthened and thickened without differences between groups. There was a significant difference when comparing the ratio SMR/SMS between groups. Ultrasound examination demonstrated different morphological changes in tendon structure depending on the treatment performed.

The anatomy of Kaplan fibers.

PURPOSE: Kaplan fibers (KF) have been described as connections between the iliotibial band and the distal femur. They are divided into two distinct structures, proximal (PKF) and distal (DKF) fibers, which may participate in the control of the rotatory knee stability. Their anatomical characteristics have not been investigated completely, in particular with respect to reconstruction procedures. The aim was to determine their anatomical characteristics and their morphological variation. METHODS: Twenty-one nonpaired fresh frozen human cadaveric knees (from whole leg) were used for the analysis of PKF and DKF through an anterolateral approach. The anatomical relationships between the adjacent anterolateral structures were reported and anatomical characteristics of PKF and DKF (thickness, width and length) measured at 50° knee flexion under different rotational conditions (neutral: NR, Internal at 5Nm: IR applied with a dynamometric torque rig). Bony ridges of PKF and DKF were measured. RESULTS: PKF and DKF and their respective bony ridges were individually identified in all knees studied (n = 21). The PKF and DKF were proximal and posterior to the lateral femoral epicondyle, respective distances 49.20 ± 7.38 and 27.54 ± 7.69 mm. DKF were thicker (p < 0.001), wider (p < 0.001) and longer (p < 0.001) than the PKF, regardless of the tibial rotation applied. Tensioning of KF was achieved in IR with a decrease in thickness and width, alongside fiber lengthening (p < 0.001). CONCLUSION: PKF and DKF are distinct and constant anatomical structures of the lateral compartment of the knee, whose anatomical characteristics and their tensioning in IR presume a function of controlling rotational knee stability.

Low Revision Rates at More Than 10 Years for Dual-Mobility Cups Cemented Into Cages in Complex Revision Total Hip Arthroplasty.

BACKGROUND: Instability and aseptic loosening are the two main complications after revision total hip arthroplasty (rTHA). Dual-mobility (DM) cups were shown to counteract implant instability during rTHA. To our knowledge, no study evaluated the 10-year outcomes of rTHA using DM cups, cemented into a metal reinforcement ring, in cases of severe acetabular bone loss. We hypothesized that using a DM cup cemented into a metal ring is a reliable technique for rTHA at 10 years, with few revisions for acetabular loosening and/or instability. METHODS: This is a retrospective study of 77 rTHA cases with severe acetabular bone loss (Paprosky ≥ 2C) treated exclusively with a DM cup (NOVAE STICK; Serf, Décines-Charpieu, France) cemented into a cage (Kerboull cross, Burch-Schneider, or ARM rings). Clinical scores and radiological assessments were performed preoperatively and at the last follow-up. The main endpoints were revision surgery for aseptic loosening or recurring dislocation. RESULTS: With a mean follow-up of 10.7 years [2.1-16.2], 3 patients were reoperated because of aseptic acetabular loosening (3.9%) at 9.6 years [7-12]. Seven patients (9.45%) dislocated their hip implant, only 1 suffered from chronic instability (1.3%). Cup survivorship was 96.1% at 10 years. No sign of progressive radiolucent lines were found and bone graft integration was satisfactory for 91% of the patients. CONCLUSION: The use of a DM cup cemented into a metal ring during rTHA with complex acetabular bone loss was associated with low revision rates for either acetabular loosening or chronic instability at 10 years.

Predictors of Functional Outcome After Microfracture Treatment of Cartilage Defects of the Knee.

INTRODUCTION: Microfracture (MFx) is a widely used technique in the treatment of articular cartilage defects of the knee. The objective of this study was to determine the prognostic factors of functional outcomes after MFx treatment of knee cartilage defects ≤ 4 cm2. MATERIALS AND METHODS: Forty-eight patients who were to be treated by MFx for knee cartilage defects ≤ 4 cm2 were prospectively included. The mean follow-up was 5.7 years (3.7-9.5). Demographics, sport practiced, time from diagnosis to surgery and associated lesions were collected. The cartilage defect was graded according to the ICRS classification. The MOCART score was calculated from a one-year MRI. The subjective VAS and IKDC scores were collected preoperatively and at the latest follow-up. Prognostic factors were determined using univariate and multivariate regression analyses incorporating pre-, peri- and postoperative clinical and radiological criteria. The dependent variable was defined as the difference between the pre- and post-operative clinical scores (dIKDC and dVAS). RESULTS: The mean size of the cartilage defect was 1.8 cm2 (0.8-4). At the last follow-up, the VAS and IKDC scores were significantly improved compared to the pre-operative period (p<0.01). The average MOCART score on the one-year MRI was 50 (20-70). Three patients (6 %) who demonstrated filling defects on MRI and debilitating pain required surgical re-intervention. The factors that impacted the functional outcome as reflected by the VAS and IKDC scores were age, BMI, time from diagnosis to surgery, size of the lesion and the MOCART score. CONCLUSION: This study demonstrates that MFx is a successful first-line treatment option for small articular cartilage defects (≤ 4 cm2) of the knee and provides good function and pain relief in the mid-term. The predictors of poor functional outcomes were older age, higher BMI, longer time from diagnosis to surgery, larger lesion size and lower MOCART score.

Medial patellofemoral ligament reconstruction with or without tibial tubercle transfer is an effective treatment for patellofemoral instability.

PURPOSE: The hypotheses were that medial patellofemoral ligament reconstruction (MPFLr) would improve the long-term symptoms of patellofemoral Instability (PFI) and control patellar tilt, based on computed tomography (CT), and that the addition of a TT transfer, when it is necessary, would not deteriorate the outcome. The purpose of this study was to evaluate the long-term clinical and radiographic outcomes of a large series of MPFLr, either isolated or associated with a TT transfer. METHODS: From 133 MPFLr with a minimum of 4 years postoperatively, three groups were defined: isolated MPFLr, MPFLr with tibial tubercle (TT) medialisation or MPFLr with TT medialisation and distalisation. IKDC and Kujala scores were evaluated. Patellar tilt was evaluated on the patient's preoperative and the last available radiograph, and on CT scan measurements performed preoperatively and at 6-month postoperatively. RESULTS: The mean follow-up was 6.3 ± 1.7 years [4.1-10.3] and four patients reported recurrent patellar dislocation. Between pre and postoperative at last follow-up a significant improvement in IKDC and Kujala functional scores was observed (P < 0.01), with no difference between the three groups. Regarding patellar tilt, there were significant decreases in Laurin and Merchant angles and an improvement of the Maldague stage (P < 0.01). The CT analysis of patellar tilt also demonstrates a significant improvement of the patella tilt (P < 0.01). The control of the patella tilt was correlated with a good functional result (P < 0.01). CONCLUSION: The MPFLr, whether isolated or associated with a TT transfer, provides good long-term clinical and radiological outcomes with a low rate of recurrence. The addition of a TT transfer, when necessary, results in the same good outcomes. This article provides a guide for surgeons evaluating PFI to choose the most appropriate procedure. LEVEL OF EVIDENCE: IV.

Outcomes of Augmented Dual Mobility Acetabular Cups.

INTRODUCTION: Total hip arthroplasty (THA) in patients with acetabular bone defects is associated with a high risk of dislocation and aseptic loosening. No studies to date have examined the use of uncemented and augmented dual mobility cups (DMC) in patients with acetabular defects. We hypothesized that the use of augmented DMC under these conditions would reduce the dislocation rate and lead to satisfactory bone integration in the medium term despite acetabular bone defects. MATERIALS AND METHODS: This continuous multicenter study included all cases of augmented DMC performed between 2010 and 2017 in patients with acetabular bone loss (Paprosky 2A: 46%, 2B: 32%, 2C: 15% and 3A: 6%). The indications for implantation were revisions for cup aseptic loosening (AL) (n=45), femoral stem AL (n=3), bipolar AL (n=11), septic loosening (n=10), periprosthetic fracture (n=5), chronic dislocation (n=4), intraprosthetic dislocation (n=2), cup impingement (n=1), primary posttraumatic arthroplasty (n=8), and acetabular dysplasia (n=4). The clinical assessment consisted of the Harris hip score (HHS) and Merle d'Aubigné Postel score (MDP), along with preoperative and final follow-up radiographs. The primary endpoint was surgical revision for aseptic acetabular loosening or the occurrence of dislocation. RESULTS: Overall, 93 patients were reviewed at a mean follow-up of 5.3 ± 2.3 years [0, 10]. As of the last follow-up, the acetabular cup had been changed in five cases: 3 AL (3.2%) and 2 infections (2.1%). Thus the overall survivorship of the cup was 94.6% and the survivorship for AL was 96.8%. Three patients (3%) suffered a dislocation. At the last follow-up visit, the mean MDP and HHS scores were 14.75 and 72.15, respectively, which reflected significant improvements relative to the preoperative scores (p < 0.05). CONCLUSION: Use of an uncemented and augmented DMC in cases of acetabular bone defect leads to satisfactory medium-term results with low dislocation and loosening rates. We recommend its use in these cases.

Ten-Year Clinical and Radiological Outcomes of 100 Total Hip Arthroplasty Cases with a Modern Cementless Dual Mobility Cup.

INTRODUCTION: The original cementless Sunfit® dual mobility cup (SERF, Décines, France) exhibited limited osseointegration due to its hydroxyapatite and alumina coating. We hypothesized that replacement of the alumina with plasma-sprayed titanium + hydroxyapatite and improvement of the external geometry (Sunfit TH®) would not increase the risk of aseptic loosening. The primary goal of this study was to determine the survivorship and clinical and radiological outcomes among patients with the Sunfit TH® implant. MATERIAL AND METHODS: This was a single-center, prospective study of the first 100 consecutive total hip arthroplasty (THA) cases performed using the combination of a press-fit Sunfit TH® dual mobility cup and a cementless straight stem. All of the cases were primary THA and the posterolateral approach was used. The patients underwent regular clinical and radiological monitoring. Radiological measurements were carried out using OsiriX® software (Pixmeo, Geneva, Switzerland). RESULTS: As of the final follow-up, 19 patients had died and 4 could not be contacted. Of the remaining patients, there were zero cases of aseptic loosening, dislocation or intraprosthetic dislocation (IPD). The survivorship was 100% at 10.03 years of follow-up. No significant implant migration was measured on radiographs. CONCLUSION: The excellent long-term outcomes with the Sunfit TH® cup are likely due to the use of plasma-sprayed titanium + hydroxyapatite in the coating and the addition of supplementary ridges and grooves to the outside of the cup. The absence of aseptic loosening, dislocation and IPD further confirms the high stability and good survivorship that can be achieved with these implants. We believe dual mobility cups should be used in patients above 60 years of age and in those below 60 years of age with a high risk of postoperative instability.

Anterolateral Ligament of the Knee: What we Know About its Anatomy, Histology, Biomechanical Properties and Function.

To better control anterolateral rotational instability (ALRI) after anterior cruciate ligament reconstruction (ACLR), many recent studies have examined the anterolateral ligament (ALL). Although some inconsistencies have been reported, anatomic studies demonstrated that the ALL runs on the lateral side of the knee from the femoral lateral epicondyle area to the proximal tibia, between Gerdy's tubercle and the fibula head. Histologic research has characterized the ALL structure, which is more than a simple capsular thickening; it shows a dense collagen core, typical bony insertions and mechanoreceptor function. An analysis of biomechanical properties suggests that the ALL is weaker than other knee ligaments. While its contributions to tibial anterior translation control and to a high grade on the Pivot-Shift test are still unclear, there is a consensus that the ALL controls tibial internal rotation. Further research will be needed to clarify the significance of ALL injuries and to gauge the value of combined ACL and ALL reconstructions.

Long-term wear of dual mobility total hip replacement cups: explant study.

PURPOSE: Dual mobility THA implantations are increasing. THA survival of more than 15 years is considered long-term survival based on the Charnley prosthesis, which has a median wear rate of 39 to 98 mm3/year. What is the median wear rate of dual mobility THA cups and its repartition on the liner volume? What are the factors influencing dual mobility wear? METHODS: Thirty-five explants were analysed. The liners were entirely mapped with a fully automatic stripe light scanner that uses green LED light. RESULTS: The liners had a median wear rate of 38 mm3/year. The distribution of the wear between the two bearings varied greatly. No factor was found influencing wear volumes. CONCLUSIONS: The median annual wear of dual mobility liners is at least as low as the wear of cemented polyethylene liners and lower than equivalent cementless liners. The two articulations of the dual mobility THA do not cause more wear. LEVEL OF EVIDENCE: Level IV - case series.

Correction to: Intraprosthetic dislocation of dual mobility total hip arthroplasty: still occurring?

The published online version contains mistake in the author list for the author name "Di Iorio Alexandre" was incorrectly presented.

Intravenous Tranexamic Acid Bolus plus Infusion Is Not More Effective than a Single Bolus in Primary Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Preoperative administration of the antifibrinolytic agent tranexamic acid reduces bleeding in patients undergoing hip arthroplasty. Increased fibrinolytic activity is maintained throughout the first day postoperation. The objective of the study was to determine whether additional perioperative administration of tranexamic acid would further reduce blood loss. METHODS: This prospective, double-blind, parallel-arm, randomized, superiority study was conducted in 168 patients undergoing unilateral primary hip arthroplasty. Patients received a preoperative intravenous bolus of 1 g of tranexamic acid followed by a continuous infusion of either tranexamic acid 1 g (bolus-plus-infusion group) or placebo (bolus group) for 8 h. The primary outcome was calculated perioperative blood loss up to day 5. Erythrocyte transfusion was implemented according to a restrictive transfusion trigger strategy. RESULTS: The mean perioperative blood loss was 919 ± 338 ml in the bolus-plus-infusion group (84 patients analyzed) and 888 ± 366 ml in the bolus group (83 patients analyzed); mean difference, 30 ml (95% CI, -77 to 137; P = 0.58). Within 6 weeks postsurgery, three patients in each group (3.6%) underwent erythrocyte transfusion and two patients in the bolus group experienced distal deep-vein thrombosis. A meta-analysis combining data from this study with those of five other trials showed no incremental efficacy of additional perioperative administration of tranexamic acid. CONCLUSIONS: A preoperative bolus of tranexamic acid, associated with a restrictive transfusion trigger strategy, resulted in low erythrocyte transfusion rates in patients undergoing hip arthroplasty. Supplementary perioperative administration of tranexamic acid did not achieve any further reduction in blood loss.

Endoscopic neurolysis of the ulnar nerve: retrospective evaluation of the first 60 cases.

BACKGROUND: The aim of this study was to determine the clinical efficacy of minimally invasive endoscopic ulnar nerve release at midterm follow-up. METHODS: This was a retrospective, consecutive, single-center study. The inclusion criterion was presentation of the patient with isolated and stable cubital tunnel syndrome. The surgical technique described by Hoffmann and Siemionow in 2006 was used for all patients. The cubital tunnel syndrome was graded by Dellon's classification and scored as described by MacDermid and Grewal in 2013. RESULTS: Sixty patients underwent surgery (62 cubital tunnel operations). Fifty-three patients were included in the study. The mean follow-up was 17 months (6-34). In the preoperative period, according to Dellon's classification, 8 patients were grade 1, 29 patients were grade 2, and 16 patients were grade 3. After surgery, according to the MacDermid score, 45 patients (84.9%) had good or excellent results, 6 (11.3%) had moderate results, and 2 (3.8%) had poor results. The mean preoperative score was 103.1 (25-181), and the mean postoperative score was 26.3 (0-135). By comparison with standard surgical technique, the endoscopic technique appears to be reliable with a similar success rate and functional improvement. The advantages are the minimally invasive portion of the surgical technique. Endoscopic control allowed complete release of the ulnar nerve with few complications. CONCLUSION: The endoscopic technique as described by Hoffman et al had similar efficacy to open surgical techniques with the advantage of being minimally invasive.

Bousquet dual mobility socket for patient under fifty years old. More than twenty year follow-up of one hundred and thirty one hips.

PURPOSE: The aim of this study was to analyze dual mobility cup survival rate on young patients under 50 years old at more than 20 years of follow up. METHODS: One hundred thirty seven hips with a first generation of dual mobility Bousquet cup (Serf) were included. The mean age at the time of the surgery was 41 years and the mean follow-up was 21.9 years. RESULTS: Twenty year follow-up cup survival rate was 77%. No dislocation occurred, 44 hips were revised (including 21 cup aseptic loosenings isolated, 15 Intra Prosthetic Dislocations), seven hips were lost to follow-up, 11 patients died, and 75 hips were still in situ. CONCLUSION: First generation dual mobility cup survival on young patient was comparable with literature results. The main complications, cup aseptic loosening and intra prosthetic dislocation, were wear-related. With improvements of the defects of first generation dual mobility, we might expect an even better survival rate with contemporary DM cups.

Results of primary total hip replacement with first generation Bousquet dual mobility socket with more than twenty five years follow up. About a series of two hundred and twelve hips.

PURPOSE: The aim of our study was to evaluate long-term survival and dislocation rate of this concept. METHODS: It was a retrospective study, on 212 hips using a Bousquet dual mobility Novae® tripodal socket (SERF). Mean follow-up was 25.3 years (95 to 372 months). Mean age at the time of the surgery was 53 years. RESULTS: Pre-operative mean Harris and PMA scores were respectively 54.14 and 11.2. Their respective last follow-up counterparts were 83.6 and 16.9; 25 year follow-up cup survival rate was 90.6%. No dislocation occurred, 45 hips were revised (including 17 cup aseptic loosenings, ten intra prosthetic dislocations, nine liner changes, seven stem failures, two sepsis). CONCLUSION: Dual mobility socket global long term survival rate was comparable to similar cemented or uncemented series. The absence of dislocations proved the interest of dual mobility concept in hip stability. Implant improvements might widen DM socket indication.

The linear penetration rate is not relevant for evaluating wear of dual mobility cups: an explant study.

PURPOSE: The linear penetration rate (LPR) has been used to estimate volumetric wear ever since metal-on-polyethylene bearings were first introduced. Annual volumetric wear and osteolysis are interrelated. The use of dual mobility cups has increased; however, the presence of two bearings needs paraclinical monitoring of wear to anticipate potential wear-related complications. Is LPR correlated to volumetric wear? METHODS: Ninety-eight dual mobility liner retrievals were mapped in three-dimensions (3D) with a fully automatic stripe light scanner. Martell's method was applied to 3D maps of the explants to determine how much the centres of the inner and outer bearings had shifted in the three planes, and in particular, penetration of the femoral head in the "z" axis. The total, inner and outer wear volumes were then compared to the shift in the centres of rotation (COR) and the pre-operative X-rays. RESULTS: There was no relationship between wear and head penetration into the liner. There was a statistically significant relationship between the 3D centre of rotation shift and inner wear or total wear. Wear was multidirectional. CONCLUSIONS: LPR is ineffective for estimating wear of dual mobility inserts, since its wear not two-dimensional. In the future, a 3D imaging method with very thin slices could be used to monitor the wear of dual mobility inserts by measuring the shift in the centres of rotation, once artifacts are overcome.

Understanding wear in dual mobility total hip replacement: first generation explant wear patterns.

PURPOSE: Dual mobility was introduced by Pr. G. Bousquet to improve the dislocation risk of total hip arthroplasty (THR). The wear mechanisms of this implant remain to be understood. Could enhanced explant wear analysis explain liner wear behaviour? METHODS: Sixty-six explanted liners were selected. Non-destructive 3D scanning and heat colour treatment allowed reporting wear patterns on both convex and concave sides of the liners. RESULTS: For many liners, liner convexity wear was found to be homogeneous, and linked to a longer implantation time. A few liners had signs of blocking of the convexity, leading to excessive internal damage. Intra prosthetic dislocations were found to only have internal circular wear without liner penetration. CONCLUSION: Heat colour treatment showed its effectiveness for highlighting wear patterns. Optimal convexity mobility seemed to be leading to a longer implantation time, with decreased contact stresses on concavity. The retentive rim should have a distinct wear analysis.

The Hemi-Castaing ligamentoplasty for chronic lateral ankle instability does not modify proprioceptive, muscular and posturographic parameters.

PURPOSE: The Hemi-Castaing ligamentoplasty uses a powerful dynamic stabilizer of the ankle which is the peroneus brevis tendon. To our knowledge, there is no study available evaluating the effects of this type of surgery on proprioceptive, muscular and posturographic parameters. METHODS: This case-control study included 39 subjects divided into two groups: the operated (n = 24) and the control group (n = 15). All subjects underwent a clinical, proprioceptive and isokinetic assessment using a CON-TREX dynamometer, and a postural evaluation using the Win-Posturo force platform. RESULTS: At a mean period of 23 (SD 5.4) post-operative months, the Karlsson ankle functional score was 84.2 (SD 23.8) and the AOFAS score was 88.1 (SD 16.2). The mean ankle joint position error for operated ankles was from 1.9° (SD 0.9) at 10° of inversion range of motion to 2.5° (SD 1.7) at 20°. It was similar to that achieved in the control group ranging from 2.2° (SD 1) at 10° to 2.3° (SD 1.3) at 20°. No significant loss of ankle eversion strength could be observed after ligamentoplasty. Ankle eversion/inversion ratio when tested under all velocities and contraction modes failed to reveal any statistical difference between the operated and healthy ankles in the patient group, neither between the patient and control groups. CONCLUSIONS: This surgical technique achieved excellent functional outcomes. It did not impair the agonist/antagonist balance of ankle muscles, and use of half the peroneus brevis tendon did not lessen the eversion strength. LEVEL OF EVIDENCE: Case-control study, Level III.

Prevention of Dislocation Risk During Hip Revision Surgery with the Dual Mobility Concept; Study of a New Generation of Dual Mobility Cups.

INTRODUCTION: Total hip arthroplasty (THA) is a common surgery presenting well-known failures that may require surgical revision. To reduce the risk of hip dislocation after revision THA, we hypothesize the interest of the use of a new generation dual mobility cup by evaluating its survival and complication rates. MATERIALS AND METHODS: We analyzed the survival and the failures rate of 91 patients who underwent revision THAs with a specific dual mobility cup Novae® E TH (SERF, Décines-Charpieu, France). The surgical indication for revision THAs were: 59 aseptic loosening or insert advanced wear (61.5%), 10 recurrent dislocations (10.9%), and 22 deep infections (24.1%). All patients underwent the same surgical technique and received a clinical and radiological examination. Failure of the cup was defined as an aseptic loosening; all failures were reported. RESULTS: During the follow up, 17 patients died and five were unaccounted for. The mean follow-up of the 86 patients included was 33 months (0-71) with a mean age of 71 years (41-99) at the time of surgery. The Postel Merle D'Aubigné (PMA) increased by 6.8 points from preoperative until the last consultation. No aseptic loosening was reported. The postoperative dislocation rate was 3.5% and 4.6% for deep infections. The overall rate for re-revision THAs was 8.1%. DISCUSSION: New choice of design and coating for the cup have demonstrated good results to reduce the rate of aseptic loosening compared to other studies. The three hip dislocations concerned two patients who had a history of recurrent dislocation and psychiatric pathologies. The limit of the study is its short follow-up, partially explained by the occurrence of 10 deaths in the first year of follow-up (lowering the mean). CONCLUSION: The use of a cementless dual mobility tripod cup for revision THA confirms its place in the possible therapeutic range by its excellent results at medium term.

Does inverse kinematic alignment coupled with robot-assisted TKA optimize patellofemoral clinical and radiological results?

INTRODUCTION: With a satisfaction rate of 80%, total knee arthroplasty (TKA) surgery has seen significant improvements in recent decades. The 20% of poor results may be explained by the alignment technique used for implant placement, which can influence patellofemoral kinematics. The objective of this study was to demonstrate that the use of inverse kinematic alignment makes it possible to obtain satisfactory clinical and radiological patellar scores in robotic TKA. HYPOTHESIS: The inverse kinematic alignment technique coupled with robotic surgery makes it possible to restore the native kinematics of the patella. MATERIALS AND METHODS: This prospective study including 100 TKAs with a primary TKA performed using the Stryker Mako™ robotic surgery system, and the inverse kinematic alignment technique. Patients who underwent patella resurfacing were excluded. Clinical and radiological scores were recorded preoperatively and 1 year postoperatively. RESULTS: At one year, the specific patellar clinical scores were excellent with an average Kujala score of 85.69 and an average HSS Patellar score 88.15. The average patellar lateralization index was 0.15 and the average patellar tilt was 5.1°, showing no significant difference compared to preoperation (p=0.45 and p=0.18). The average external rotation of the femoral implant was 0.47±0.6° [-1.9; 2.1]. DISCUSSION: The patellofemoral clinical results were excellent. The use of the robotic arm coupled with this alignment technique makes it possible to obtain a controlled external rotation of the femoral implant as well as an optimized orientation of the tibial component, favoring good restitution of the alignment of the extensor apparatus. This study did not demonstrate any radiological correction of patellar tilt and lateralization. CONCLUSION: The combined use of robotic surgery with the inverse kinematic alignment technique seems effective on specific clinical results of the patellofemoral joint. LEVEL OF EVIDENCE: II; prospective cohort.