Plantar compartment block for hallux valgus surgery: a proof-of-concept anatomic and clinical study.

BACKGROUND: Hallux valgus surgery is associated with moderate to severe postoperative pain. We hypothesized that a plantar compartment block may be a good technique for postoperative analgesia. We describe an anatomic approach to ultrasound-guided plantar compartment block and assess the clinical efficacy of the block for outpatient surgery. METHODS: The anatomic study was aimed to describe the plantar compartment, using both dissection methods and imaging, and to define a volume of local anesthetic. Patients scheduled for hallux valgus surgery with a popliteal sciatic nerve block, and combined plantar compartment and peroneal blocks were included in the clinical study. Data on attaining the criteria for rapid exit from the outpatient center, duration of sensory and analgesic block, visual analog scale (VAS) values for postoperative pain at rest and during movement, and the consumption of morphine as rescue analgesia were recorded. RESULTS: Plane-by-plane dissections and cross-sections were done in five cadaveric lower limbs. The medial calcaneal nerve divides into medial plantar and lateral plantar nerves in the upper part of the plantar compartment. These nerves were surrounded by 5 mL of colored gelatin, and 10 mL of injectates dye spread to the medial calcaneal branches. Thirty patients (26 women) were included in the clinical study. There were no failures of surgical block. Ninety per cent of patients successfully passed functional testing for ambulatory exit from the center within 5 hours (25th-75th centiles, 3.8-5.5 hours). The median duration of plantar compartment sensory block was 17.3 hours (10.5-21.5 hours), and the first request for rescue analgesic was 11.75 hours (10.5-23 hours) after surgery. The median VAS score for maximum pain reported within the 48-hour period was 2 (1-6). Twelve patients received 2.5 mg (0-5 mg) of morphine on day 1. Patients were highly satisfied and no adverse events were noted. CONCLUSIONS: This anatomic description of the ultrasound-guided plantar compartment block reported the injection area to target the medial and lateral plantar nerves with 5 mL of local anesthetic. Normal walking without assistance is attained rapidly with this regional anesthesia technique, and the time to request postoperative analgesia after hallux valgus surgery is long. TRIAL REGISTRATION NUMBER: NCT03815422.

Finite element analysis in the optimization of posterior-stabilized total knee arthroplasty.

Posterior-stabilized total knee arthroplasty (PS-TKA) is associated with high rates of satisfaction and functional recovery. This is notably attributed to implant optimization in terms of design, choice of materials, positioning and understanding of biomechanics. Finite elements analysis (FEA) is an assessment technique that contributed to this optimization by ensuring mechanical results based on numerical simulation. By close teamwork between surgeons, researchers and engineers, FEA enabled testing of certain clinical impressions. However, the methodological features of the technique led to wide variations in the presentation and interpretation of results, requiring a certain understanding of numerical and biomechanical fields by the orthopedic community. The present study provides an up-to-date review, aiming to address the following questions: what are the principles of FEA? What is the role of FEA in studying PS design in TKA? What are the key elements in the literature for understanding the role of FEA in PS-TKA? What is the contribution of FEA for understanding of tibiofemoral and patellofemoral biomechanical behavior? What are the limitations and perspectives of digital simulation and FEA in routine practice, with a particular emphasis on the "digital twin" concept? LEVEL OF EVIDENCE: V, expert opinion.

Combined structural allograft and tantalum cone to manage segmental metaphyseal tibial bone defect in revision knee arthroplasty.

Tibial bone defect remains a challenge in revision knee arthroplasty. The present innovative technique combines structural allograft and tantalum metaphyseal cone for treatment of AORI stage 2A and 2B (uncontained peripheral metaphyseal) tibial defect. The aim is to reconstitute bone stock and enhance allograft osseointegration, while limiting stress to the allograft by implanting the metaphyseal cone through the allograft and the original bone. LEVEL OF EVIDENCE: V (expert opinion).

Influence of kinematics of the lumbopelvic complex in hip arthroplasty dislocation: from assessment to recommendations.

INTRODUCTION: In total hip arthroplasty (THA), misplacement of the implant can provide instability. Adequate orientation of the acetabular cup is a challenge due to variations in inter-individual anatomy and kinematics of the pelvis in everyday life. The aim of this study was to characterize the kinematic factors influencing the risk of dislocation in order to give recommendations for optimal placement of the cup. We hypothesized that the lack of pelvic adaptation would influence the risk of prosthetic instability and motivate adapted. MATERIALS AND METHODS: Eighty patients with primary unilateral THA were included in a matched case-control study. Seventy-four patients were divided into two groups: group 1 (G1) consisting of patients with postoperative THA dislocation (37 patients) and group 2 (G2), without episodes of dislocation within two years postoperatively (37 patients). In both groups, spino-pelvic parameters and cup orientation were measured in standing and sitting positions with EOS® X-ray imaging and compared to each other between 12 and 24 months post-operatively. RESULTS: No significant difference between the two groups was found for static parameters. In a sitting position, a lack of pelvic retroversion with a significant lower variation in sacral slope was observed in group 1 (8.0° ± 9.3 for G1 versus 14.7° ± 6.2 for G2, p < 0.01). Twenty-two (59%) patients with THA instability had sacral slope variations of less than 10° versus eight (21% of patients) with stable THA (p < 0.01). Cup orientation in the Lewinnek safe zone was not significantly different (59% vs 67%, p = 0.62), and the spino-pelvic parameters and cup orientation measured did not change between the standing and sitting positions. However, only 14 (37%) cups in G1 were in the functional safe zone versus 24 (67%) in G2 (p = 0.03). CONCLUSION: Static parameters of the sagittal spinopelvic balance have a low predictive value for prosthetic instability. Dynamic analysis is essential. Kinematic parameters must be taken into account in determining the ideal position of the cup or stem. Stiffness with locked standing or sitting pelvis must be integrated in order to determine a personalized safe zone. LEVEL OF EVIDENCE: Level III (matched case-control study).

Validation of a novel finite-element model for evaluating patellofemoral forces and stress during squatting after posterior-stabilized total knee arthroplasty.

INTRODUCTION: Several studies have documented the relationship between patellofemoral pain and patient dissatisfaction after total knee arthroplasty (TKA). However, few computer simulations have been designed to evaluate the patellofemoral joint during flexion. The aim of this study was to validate a new computational simulation, driven by forces and moments, and to analyze patellofemoral reaction forces and stress under squat loading conditions after TKA implantation. HYPOTHESIS: This computational simulation of a squat using a model driven by forces and moments is comparable to in vitro and in silico data from the literature. MATERIAL AND METHODS: We developed a finite element model of the lower limb after implantation of a fixed-bearing posterior-stabilized TKA. To simulate squat loading conditions when standing on both legs, an initial load of 130N was applied to the center of the femoral head. Quadriceps force, patellofemoral contact force and Von Mises stress on the patellar implant, tibiofemoral contact forces and pressure on the tibial insert, and post-cam contact force were evaluated from 0° to 100° of knee flexion. RESULTS: Quadriceps force increased during flexion, up to 6 times the applied load. Von Mises stress on patellar implant increased up to 16MPa at 100° flexion. Tibiofemoral contact forces increased up to 415 N medially and 339 N laterally, with 64% distributed medially on the tibial insert. Post-cam contact started slightly before 70° of flexion. DISCUSSION: In this simulation, tibiofemoral, patellofemoral and post-cam contact forces, and pressure distribution on the tibial insert were consistent with various published studies. This agreement suggests that computational simulation driven by forces and moments can reproduce squat loading conditions during knee flexion after TKA, without experimental kinematic data used to drive the simulation. CONCLUSION: This study represents an initial step towards validating tibiofemoral and patellofemoral mechanical behavior under squat conditions, from this computational simulation driven by forces and moments. This model will help us better understand the influence of various implantation techniques on patellofemoral forces and stress during flexion. LEVEL OF EVIDENCE: IV, biomechanical computational study.

Are modern knee outcomes scores appropriate for evaluating anterior knee pain and symptoms after total knee arthroplasty?

BACKGROUND: Up to 45% of patients who undergo primary total knee arthroplasty (TKA) with contemporary implants have residual anterior knee pain. While a specific evaluation of anterior knee symptoms is mandatory, little is known about the capability of patellofemoral scores to be used individually. This study aimed to assess the distribution of patellofemoral scores after TKA from a uniform cohort and to investigate their external validity and ability to detect anterior knee symptoms using floor and ceiling effects. HYPOTHESIS: Patellofemoral scores have high construct validity and fewer floor/ceiling effects than general knee scores. METHODS: We prospectively included 113 consecutive patients who underwent primary TKA for primary osteoarthritis at a single University Hospital. Clinical outcomes included patellofemoral scores (HSS Patella, Kujala and Lille scores) and general knee scores (KOOS and new KSS) at 1-year follow-up. The floor and ceiling effects were considered as significant when greater than 15%. These were determined for each score individually and for composite scores (combination of patellofemoral scores and new KSS). The construct validity of each score and their ability to detect anterior knee pain was evaluated. RESULTS: Patellofemoral scores showed no floor effect but a significant ceiling effect (from 25% to 65%). This ceiling effect decreased when composite scores were used. The convergent validity test showed strong correlation between patellofemoral scores (from 0.741 to 0.819, p<0.00001) and a better ability to discriminate anterior knee pain than the general knee scores. CONCLUSIONS: Patellofemoral scores showed no floor effect and a very good construct validity for anterior knee pain after TKA. However, studies aiming to monitor anterior knee symptoms after TKA should combine scoring systems to included patellofemoral-related items rather than use patellofemoral scores alone due their ceiling effects. LEVEL OF EVIDENCE: III; prospective study.

Influence of residual anterior laxity on functional outcomes after anterior cruciate ligament reconstruction.

INTRODUCTION: Residual laxity can persist after anterior cruciate ligament (ACL) reconstruction. This increased anterior translation can be measured with a knee arthrometer. Nevertheless, the measurement parameters and functional impact of this residual laxity are not well understood. The aims of this study were to (1) evaluate the effect of applying loads of 134N, 200N and 250N on the measured residual laxity after ACL reconstruction and (2) evaluate the prognostic ability of the various measurement parameters on the functional outcomes. HYPOTHESIS: After ACL reconstruction, the functional outcomes will be correlated to the postoperative residual laxity. METHODS: We did a prospective study of 61 recreational athletes who underwent surgical reconstruction of their ACL with the Kenneth-Jones technique between 2016 and 2019. The mean age of these patients was 27±7 years, and most were men (75%). The side-to-side difference in laxity was measured pre- and postoperatively using the GNRB® arthrometer at three load levels: 134N, 200N and 250N. The functional outcomes were determined based on the return to sports and the KOOS, IKDC and ARPEGE scores. The mean follow-up was 30±10 months. RESULTS: Half the patients had returned to sport at their pre-injury levels, while 25% had returned to a lower level and 25% had stopped doing any physical activity. At 134N, a 1-mm increase in side-to-side difference was associated with a 2-fold higher risk of not returning to sports (OR 2; 95% CI 1.22-3.23; p<0.01). At 200N, a 1-mm increase in side-to-side difference was associated with a 50% higher probability of having a poor/fair ARPEGE score (OR 1.5; 95% CI 1.05-2.02; p=0.02). At 200N, a 4-mm side-to-side difference was the prognostic threshold for failure to return to sports with a positive predictive value of 86% and specificity of 98%. CONCLUSIONS: This case series found a strong correlation between residual laxity and the functional outcomes after ACL reconstruction. A threshold of 4mm residual laxity evaluated on the GNRB® at 200N was predictive of adverse outcomes and failure to return to sports in our population of recreational athletes. LEVEL OF EVIDENCE: IV, retrospective study.

Survivorship of 4,748 Contemporary Total Ankle Replacements from the French Discharge Records Database.

BACKGROUND: Studies of survivorship of primary total ankle replacements (TARs) beyond 5 years have shown varying results among early and modern designs. National cohorts give valuable insights about TAR outcomes, revision risk factors, and specific designs. The purpose of this study was to investigate implant survivorship and risk factors for revision of contemporary TARs using our national database. METHODS: This observational study included patients identified in the national PMSI (Programme médicalisé des systèmes d'information) database as having undergone TAR from 2010 to 2019. Demographics, discharge data, concomitant procedures, and type of implant were extracted. Kaplan-Meier estimations were performed to determine time to revision using metal component revision for implant failure and revision for deep infection as end points. Weighted Cox models were used for risk factor analysis, including risks of early revision (within the first 2 years). The adjusted hazard ratios (HRadj) were reported with 95% confidence intervals. RESULTS: A cohort of 4,748 patients was extracted. The mean age at surgery was 63 years; 43% of the patients were female. The mean follow-up was 5 years (range, 1 to 10 years). Revisions were noted in 817 cases (17%), including 734 with metal component revision and 83 with revision due to deep infection. The 1-year, 2-year, 5-year, and 10-year survivorship free of metal component revision was 95%, 90%, 84%, and 78%, respectively. Younger age, implants derived from second-generation designs, and an institutional volume of ≤10 TARs per year were found to be independent predictors of revision for any cause. In addition to the above factors (except for implant generation), male sex and concomitant osteotomies and/or fusion were found to be significant predictors for any early revision. CONCLUSIONS: The 10-year survivorship free of metal component revision after TAR was 78%, which was consistent with other national registries. Revisions were associated with young age, associated arthritis or deformities requiring concomitant fusion or osteotomy, and implants derived from second-generation designs. Institutions where >10 procedures were performed per year were associated with better TAR survivorship. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Influence of dual-mobility acetabular implants on revision and survivorship of cup and Kerboull-type reinforcement ring constructs in aseptic acetabular loosening.

INTRODUCTION: Dual-mobility (DM) acetabular implants have been used in revision total hip arthroplasty (THA) to prevent postoperative instability, with excellent mid-term survivorship. However, few comparative studies assessed the long-term outcomes of DM implants used in Kerboull-type reinforcement ring constructs for acetabular revision. The present study aimed to compare long-term survivorship, dislocation rates and clinical outcome between DM acetabular implants and conventional single-bearing (SB) implants when cemented in a reinforcement ring. HYPOTHESIS: Dual-mobility implants are associated with equivalent survivorship and lower dislocation rates than SB implants. MATERIAL AND METHODS: A retrospective study included 60 revision THAs for aseptic loosening using a Kerboull-type reinforcement ring, and finally included 2 groups of 23 patients with either DM or SB cemented acetabular implants after matching for age, gender, BMI and preoperative Harris hip score. Mean follow-up was 10 years (range, 6-14 years). Acetabular implant survivorship, dislocation rate and radiographic failure incidence (>5mm migration, progressive radiolucency, graft non-integration, reinforcement ring breakage) were compared between the two groups. Clinical outcomes used the Harris hip score, the Postel-Merle d'Aubigné score and the Parker score. RESULTS: Survivorship free of aseptic acetabular re-revision was 89% at 10 years, with no significant difference between DM and SB (91% and 86%, respectively; p=0.54). Single-bearing implants showed a hazard ratio for dislocation of 6.7 (95% CI, 1.5-29.6; p=0.01) compared to DM implants. There were no significant differences in radiologic failure (10-year survivorship 72% and 64%, respectively; p=0.88) or functional scores. DISCUSSION: The present study confirmed the impact of dual-mobility implants in reducing long-term dislocation risk when used in Kerboull-type reinforcement ring constructs for acetabular aseptic revision, with no increased risk of re-revision compared to conventional single-bearing implants. LEVEL OF EVIDENCE: III, comparative retrospective study.

Clinical, Economic, and Organizational Impact of the Clinical Pharmacist in an Orthopedic and Trauma Surgery Department.

AIM: The aim of this study was to evaluate the clinical, economic, and organizational impact of clinical pharmacist services added to an adult orthopedic and trauma surgery unit in a university hospital. METHODS: This was a prospective, observational study performed from January to February 2017. All pharmacists' interventions were documented, and their clinical, economic, and organizational impact and the probability of adverse drug events (ADEs) were assessed using the clinical, economic and organizational scale three-dimensional scale. An expert panel composed of three clinical pharmacists, one surgeon and one anesthetist classified the pharmacist intervention. The potential clinical impact was determined through a consensus by the expert panel. Cost avoidance was calculated for serious ADEs with a major impact by avoiding an additional cost of €4912 per event and taking into account the probability of ADE occurrence. RESULTS: The pharmacists performed 1014 interventions for 28 days with a 95.3% acceptance rate by prescribers. Thirty-nine interventions were rated to have a major clinical impact (3.8%). The organizational impact was estimated favorable for 856 (84.4%) pharmacist interventions. Cost avoidance was estimated at €24,364, and the indirect costs benefit was estimated at €11,864 during the study. The cost-benefit ratio of the clinical pharmacist intervention was €1.94 in savings for every €1 invested. CONCLUSIONS: Clinical pharmacist services in an orthopedic and trauma surgery department have the potential to improve patient outcomes and avoid healthcare costs. Furthermore, the presence of a pharmacist in surgical units allows for communication between the unit and the pharmacy, which produces better fluidity and improves the quality of care.

Influence of a temporary stabilization device on respiratory status in patients with severe trauma with a femoral shaft fracture treated by damage control strategy.

BACKGROUND: There are few studies on the safety and respiratory consequences of the use of a skeletal traction (ST) device in the management of femoral shaft fractures with damage control orthopaedics (DCO) strategy, particularly in cases of prolonged use. The aim of this study was to assess the influence of ST compared with an external fixator (EF) on respiratory complications and mechanical ventilation requirements in patients with severe trauma with a femoral shaft fracture managed by DCO strategy. METHODS: We retrospectively reviewed all patients with severe trauma patients with a unilateral femoral shaft fracture admitted to our institution from 2010 to 2015. Patients who did not undergo definitive osteosynthesis during the first 24 h were included and divided into two groups: DCO-ST group and DCO-EF group. In addition to trauma severity, global management of respiratory complications, the incidence of acute respiratory distress syndrome (ARDS) and mechanical ventilation requirements and outcome were compared. RESULTS: Fifty-five patients were managed with DCO strategy (mean Injury Severity Score, 28.4); there were 31 in the DCO-ST group and 24 in the DCO-EF group. No significant difference in terms of the main characteristics, initial severity and associated injuries was observed between the two groups. In contrast, ARDS was found more frequently in the DCO-ST group (81% versus 54%; P = 0.035). Number of ventilation days also tended to be higher in the DCO-ST group (9 days [IQR 3-15 days] versus 7 [IQR 2-16 days]; P = 0.24). No difference was found for mortality and hospitalization duration between the DCO-ST and DCO-EF groups. CONCLUSION: The prolonged use of an ST device in the present cohort was associated with a higher incidence of impaired respiratory function. Therefore, our findings suggest that EF is preferable to ST in the DCO setting for femoral shaft fracture, especially in trauma patients at high risk of developing delayed respiratory failure.

Femoral neck shortening after internal fixation of Garden I fractures increases the risk of femoral head collapse.

BACKGROUND: Arthroplasty has not been proven superior over internal fixation for the treatment of non-displaced femoral neck fractures. However, internal fixation has been followed by high rates of revision for mechanical complications and of femoral neck impaction within the first postoperative year. The objective of this study was to determine whether femoral neck impaction was associated with avascular necrosis (AVN). HYPOTHESIS: Fracture healing with femoral neck shortening by impaction after internal fixation of a femoral neck fracture is associated with AVN. MATERIAL AND METHODS: A single-centre retrospective study in patients with Garden I fractures managed by screw fixation was performed to compare outcomes in the groups with and without femoral neck impaction. Follow-up radiographs were assessed for evidence of the femoral neck impaction during fracture healing. The occurrence of AVN was the primary evaluation criterion. The secondary evaluation criteria were risk factors for impaction and complications. RESULTS: Of the 75 included patients, 9 (12%) experienced AVN. Impaction was significantly associated with AVN (p=0.02; relative risk, 4.38). Significant risk factors for impaction were a higher body mass index (p=0.0003) and valgus-impacted fracture reduction between the radiographs at baseline and immediately after surgery (p=0.0001). DISCUSSION: Femoral neck impaction was a significant risk factor for AVN after screw fixation of Garden I fractures. Valgus-impacted fracture reduction must receive careful attention during fixation. We suggest static internal fixation if the impaction is reduced on a traction table and advise caution when using parallel screws. The diagnostic and therapeutic strategy proposed here deserves to be evaluated in a prospective study. LEVEL OF EVIDENCE: III, retrospective comparative study.

Are modern knee outcomes scores appropriate for evaluating patellofemoral degeneration in osteoarthritis? Evaluation of the ceiling and floor effects in knee outcomes scores.

INTRODUCTION: Patellofemoral (PF) degeneration plays an important role in knee function in the context of osteoarthritis. A specific evaluation of PF symptoms is needed to better understand the initial functional status of the knee before surgery. The aim of this study was to assess the validity of patient-related outcome measures (PROMs) for knee scores and PF scores in knee osteoarthritis. HYPOTHESIS: PF scores are more reliable for evaluating anterior knee pain than global knee scores in the context of PF degeneration in osteoarthritis. MATERIAL AND METHODS: We performed a prospective single-center study of continuous patients included between January 2017 and January 2018 in our surgical department for total knee arthroplasty (TKA) for primary knee osteoarthritis. The analysis used global knee PROMs (KOOS and new IKS) and PF-specific PROMs (HSS Patella score, Kujala score and Lille score). Floor and ceiling effects were determined for each score based on tibiofemoral and PF degeneration on radiographic views; it was considered significant when greater than 15%. RESULTS: We included 114 TKA procedures in 113 consecutive patients. According to the Iwano classification, no significant floor or ceiling effect was found for the PF preoperative scores (0-12%). The KOOS ADL and QOL scores were particularly affected by the ceiling and floor effects, whatever the patellofemoral degeneration (23-88%). In cases of severe PF degeneration (Iwano grade 3 and 4), no significant differences in the distribution of the functional scores were found. DISCUSSION: Modern knee outcome scores used to evaluate knee function do not monitor PF degeneration and related symptoms in the context of knee osteoarthritis according to the Iwano classification. PF scores do not have a floor and ceiling effects even if the severity of the PF degeneration is difficult to identify preoperatively. Physicians should be aware of this effect on the preoperative functional evaluation before TKA. LEVEL OF EVIDENCE: III, comparative prospective study.

Compared efficiency of trauma versus scheduled orthopaedic surgery operating rooms in a university hospital.

BACKGROUND: The objective of this study was to contribute to an OR efficiency optimisation effort by comparing a trauma OR versus a scheduled surgery OR in a lower limb orthopaedic surgery department. HYPOTHESIS: The main hypothesis is that efficiency is lower in the trauma OR than in the scheduled surgery OR. The secondary hypothesis is that efficiency of the trauma OR is lower during weekends. MATERIAL AND METHODS: This prospective study was conducted in 2016 in the orthopaedic surgery department of a university hospital. Patients were divided into three groups based on whether they underwent scheduled surgery (SchOS), trauma surgery on a weekday (TSwk), or trauma surgery on a weekend (TSwkend). Actual OR occupancy time, allocated OR block time (BT), OR occupancy rate, patient entrance-to-incision time, incision-to-closure time, closure-to-post-anaesthesia care unit (PACU) entrance time, and clean-up/set-up time (T4) were measured. RESULTS: We included 691 patients in the SchOS group, 819 in the TSwk group, and 327 in the TSwkend group. OR efficiency was lower in the TSwk group compared to the SchOS group (occupancy rate, 86% vs. 88%; p=10-4). All occupancy time components were longer in the TSwk group. However, each component accounted for similar total occupancy time proportions in the two groups, except for clean-up/set-up time, which was longer in the TSwk group (p<0.05). On average, entrance-to-incision time accounted for 31%, incision-to-closure time for 34%, closure-to-PACU time for 18%, and clean-up/set-up time for 17% of total occupancy time. Efficiency was lower in the TSwkend group than in the TSwk group (occupancy rate, 75% vs. 86%; p=10-4). The TSwkend group had shorter entrance-to-incision and incision-to-closure times (p<0.05) and a nearly 10% longer clean-up/set-up time (p<0.05). CONCLUSION: Efficiency of the trauma OR, although lower compared to the scheduled orthopaedic surgery OR, was nevertheless satisfactory as assessed based on standard indicators. Of the four total occupancy time components, the first three accounted for similar proportions of the total; differences occurred only for clean-up/set-up time. Efforts to improve OR efficiency should focus on arrival of the first patient and turnover time. LEVEL OF EVIDENCE: II, prospective cohort study.

Cementless revision femoral stems application of press-fit principles and clinical outcomes.

BACKGROUND: Cementless femoral stems are currently used in revision total hip arthroplasty (THA) with the surgeon choosing between various fixation modes. The outcomes are good in the medium term; however, some failures have been attributed to technical errors during implantation. When the decision has been made to use a press-fit implant, the impact of the surgeon's technique on the functional outcomes have not been explored in-depth. This led us to carry out a retrospective study on a large population of total hip arthroplasty patients which aims were achieved press-fit to (1) determine the impact of the type of primary fixation (with and without press-fit) on the functional outcomes; (2) specify the effect of stem length on the functional scores when diaphyseal press-fit is achieved and (3) analyse the main reasons why a true press-fit effect was not achieved (three-point fixation). HYPOTHESIS: There is a relationship between the primary fixation method by press-fit of a revision femoral stem and the functional outcomes. PATIENTS AND METHODS: We performed a retrospective analysis of a continuous cohort of 244 THA revision cases with a mean follow-up of 6.1 ± 3.5 years (range, 2-18). The femoral area in which close contact was achieved (shared interface between the bone and implant) was used to define various types of press-fit fixation. The functional outcomes were determined using the Harris Hip Score (HHS) and the Merle d'AubignéPostel score (MAP score) out of 12 points (pain and walking items). RESULTS: The post-operative HHS averaged 90.83 ± 7.51 for proximal press-fit and 80.14 ± 14.93 with no press-fit (p = 0.01). The MAP averaged 10.83 ± 1.03 for proximal press-fit and 9.75 ± 2.09 with no press-fit (p = 0.09). The MAP score was worse for long diaphyseal press-fit than for short press-fit (p = 0.02). Use of a long stem with an endofemoral route or an overly small femoral window in patients with a curved femur is the main reason that three-point fixation occurred instead of press-fit. CONCLUSIONS: While press-fit is an effective concept, it is a demanding one that requires the surgeon to choose the correct surgical strategy for the patient's anatomy. A meticulous surgical technique is required to achieve proximal press-fit or at a minimum, short diaphyseal press-fit.

Dual mobility device reduces the risk of prosthetic hip instability for patients with degenerated spine: A case-control study.

INTRODUCTION: The pelvic incidence is an anatomical and biomechanical pelvic parameter determining spine sagittal morphology and kinematics. Stiffening of the lumbo-pelvic complex, a result of degeneration, affects the functional cup positioning, putting prosthetic hip patients at risk of instability. The anti-dislocation dual mobility (DM) device may be clinically advantageous by reducing the risk of prosthetic instability for older patients with spine ageing. Our study aims to answer the following questions: (1) is there a relationship between prosthetic hip instability and the standing cup position, (2) is there a relationships between prosthetic hip instability and the pelvic incidence, (3) is there a relationships between prosthetic hip instability and the severity of the spine degeneration?, (4) is the DM cup device an effective option for reducing the risk of prosthetic instability related to spine degeneration? HYPOTHESIS: There is a relationship between prosthetic hip instability and the standing cup position and pelvic parameters. METHODS: Case-control study on prospectively collected data since 2009. From 1672 conventional total hip replacements (THR-5.4% dislocation rate) and 1056 DM-THRs (1.1% dislocation rate) performed at our institute since 2009, we created three groups: 33 patients with unstable THR (group 1-case), 41 patients with stable THR (group 2-control), and 42 patients with stable DM-THR (group 3-control). The cup orientation was measured on standing pelvic radiographs and the spino-pelvic parameters were measured on standing EOS™ biplanar images or lateral full spine radiographs. RESULTS: By comparing patients from group 1 with those of group 2 we found they had similar cup position (57% versus 51% fitting the safe zone, p=0.58), higher pelvic incidence (58° versus 51°, p=0.01), and more severe spine degeneration (smaller anterior pelvic plane Tilt (2° versus 7° [p=0.002]), a larger pelvic incidence-lumbar lordosis mismatch (17° versus 8° [p=0.005]), and a higher proportion of spino-sacral angle<127° (70% versus 43%, (p=0.02)). Patients from group 3 had similar cup position, pelvic incidence, and spine degeneration compared to patients from group 1. DISCUSSION/CONCLUSION: Patients with spine-hip relation type 2C/D (high pelvic incidence and severe spine degeneration) have an increased risk of instability that is partly compensated for by the use of a DM device. Preoperative screening of patients with abnormal spine-hip relation would improve THR planning and reduce the risk of prosthetic hip instability. The use of a DM device on spine-degenerated elderly patients is probably sound. LEVEL OF EVIDENCE: III, case-control study.

Global radiological score for femoral cementless revision stem.

PURPOSE: The purpose of this study was to evaluate the outcomes of total hip arthroplasty (THA) revision with cementless stems using a numeric global radiological score (GRxS) that summarizes two previously validated scores: secondary bone stock (SBS) and osseointegration-secondary stability (O-SS). METHOD: One hundred fifty cases of THA were evaluated at a mean follow-up of 6.5 ± 3.7 years. The GRxS combines the SBS, which evaluated cortical bone thickness, bone density and bone defects in each Gruen zone and the O-SS, which evaluated the location and extent of a single radiolucent line. To calculate the GRxS, the SBS and O-SS were each expressed on a 10-point scale and given equal weighing. The final result was a number out of 20. The GRxS was used to assign a radiological grade to each THA case: very good (20), good (18-15), average (13-12), or poor (≤ 10). The numerical mean (Nm) was calculated for each grade. The inter- and intra-observer reproducibility was evaluated. RESULTS: The inter-observer reproducibility was good (0.8) and the intra-observer reproducibility was very good (0.9). The GRxS was considered very good in 46 cases (Nm 20), good in 57 cases (Nm 16.6), average in 25 cases and poor in 22 cases. There was a significant relationship between the GRxS and the Harris Hip and Postel Merle d'Aubigné scores (p < 0.0001), and the initial bone stock (p = 0.0001). CONCLUSIONS: The GRxS is reliable and reproducible. This information can be used by surgeons to adapt the surgical technique to bone characteristics (especially during revision cases) and to compare the outcomes of different implant designs.