Dual-mobility tripod cup for revision hip arthroplasty: long-term (five to fourteen years) evaluation of a new generation cementless implant.

PURPOSE: The aims of this study were to evaluate the survivorships of a new generation cementless DMC with tripod additional fixation in revision total hip arthroplasty and complications at a minimum five year follow-up. METHODS: One hundred and fifteen revisions (THA) treated with tripod DMC performed between 2009 and 2015 were included in this retrospective study. Acetabular defects were classified as Paprosky 1 (n = 38, 33%), 2 (n = 75, 65%) or 3 (n = 2, 2%). Unipolar or bipolar revision was performed for the following indications: aseptic acetabular loosening (63%), infection (14%), aseptic bipolar loosening (11%), instability (4%), aseptic femoral loosening (3%), ALVAL (3%) and iliopsoas impingement (2%). Mean follow-up was 9.4 years ± two (range, 5 to 14). RESULTS: At the final follow-up, a single episode of dislocation occurred within three months after the procedure (0.8%) with no revision. Three cases of aseptic loosening were diagnosed (2.6%). Four infections (3.5%) required reoperation: three required a two stage bipolar revision; one was treated by DAIR procedure. At the latest follow-up, the survivorship of the acetabular cup for aseptic loosening was 98% [95% CI (91.2-99.4)] and for any reasons was 94.4% [95% CI (90.1%-98.9%)]; the mean HHS improved from 60 points (range, 18-94 points) to 83 points (range, 37-100 points) (p < .001). CONCLUSION: This study reports a low complication rate in favour of the use of a tripod DMC in revision THA with a satisfactory survivorship at a ten year follow-up.

Evaluation of containment measures' effect on orthopaedic trauma surgery during the COVID-19 pandemic: a retrospective comparison between 2019 and 2020.

BACKGROUND: There is no available information about the effect of containment measures on trauma surgery activity. The aim of this study was to analyse and report the containment measures' impact on trauma surgery activity during the COVID-19 pandemic in order to quickly react and adjust in case of a new sanitary crisis and containment. METHODS: An original epidemiological study was performed in our trauma centre in France. Data from trauma surgeries performed during the pre-containment (from March 1 to March 16, 2020), containment (from March 17 to April 17, 2020) and reference (from March 1 to April 17, 2019) periods were compared. The primary outcome was the number of patients operated on daily and the daily operating room time. Clinical data, delay for surgery, mechanism of injury and injury pattern were also reviewed. RESULTS: There was a statistically significant decrease in the number of patients operated upon daily (- 39,8%, p value < 0.001) and daily operating room time (- 35.5%, p value < 0.001) between the reference and containment periods and between the pre-containment and containment periods (respectively, - 35.0%, p value < 0.001 and - 28.7%, p value 0.002). No differences were reported between the reference and pre-containment periods for daily-operated patients (p value 0.359). CONCLUSION: Containment measures had a direct impact on trauma surgery activity with a decrease of a third of trauma surgery activity. Those results could be useful if a new containment occurred.

The influence of the sacral slope on pelvic kinematics and clinical manifestations in femoroacetabular impingement.

INTRODUCTION: The radiological study of the sagittal alignment of the spine in static and dynamic positions has allowed a better understanding of the clinical results of total hip prostheses. According to the Roussouly classification, the sacral slope in a standing position characterizes the patient with a stiff spine (less than 35̊) or a flexible spine (greater than 35̊). The objectives of this study were to compare, in a population of patients operated on for femoroacetabular impingement (FAI), firstly, the kinematics of the lumbar-pelvic-femoral complex and secondly, the clinical presentation depending on whether the spine is stiff or flexible. HYPOTHESIS: Patients with stiff spines (SS<35̊) were "hip users" and had less ability to compensate for their hip pathology. MATERIAL AND METHOD: This prospective and comparative multicenter study was conducted with patients operated on arthroscopically for FAI between 2020 and 2021. All patients included received preoperative EOS imaging of the lower limbs and spine, in standing and seated positions. The following parameters were measured: pelvic tilt (PT), pelvic incidence (PI), lumbar lordosis (LL), and sacral slope (SS), as well as dynamic parameters (intrinsic mobility of the hip: delta standing/sitting femoral sacral angle, and of the pelvis: delta standing/sitting sacral slope). The functional result was evaluated at 1 year. RESULTS: In the stiff spine group, 62 patients were included versus 138 in the flexible spine group. The mean follow-up was 15.1±3.3 months (9.2-24.3). Nineteen patients were lost to follow-up and there were 2 revisions for iterative arthroscopy. Intrinsic pelvic mobility and intrinsic hip mobility were 16̊±13.5 (-12; 44) and 44.5̊±28.5 (-9; 99) respectively in the stiff spine group. In the flexible spine group, these same measurements were 22̊±11.5 (-30; 45) and 29.7̊±22.7 (-33; 82) respectively. In the stiff spine group, the symptoms occurred at a significantly younger age: 28.3 years±9.5 (18-51) versus 31 years±8 (18-54) (p=0.017). DISCUSSION: The sacral slope is a determining factor in the kinematics of impingement and the appearance of symptoms. The sacral slope helps define the concept of a "hip user" in symptomatic FAI. LEVEL OF EVIDENCE: IV.

Radiological signs of femoroacetabular impingement are linked to pelvic version in asymptomatic subjects.

INTRODUCTION: With the recent interest in hip-spine relationship, the link between femoroacetabular impingement (FAI) and the lumbar-pelvic-femoral complex (LPFC) appears decisive. The objectives of this study were (1) to compare the pelvic version, as well as (2) all the parameters of the LPFC between two populations of healthy subjects, comparing those with radiological signs of FAI to those without and finally, (3) to evaluate the LPFC parameters according to the type of FAI. HYPOTHESIS: Asymptomatic subjects with radiological signs of FAI had superior pelvic anteversion. MATERIALS AND METHOD: This retrospective study was based on a prospective cohort of 118 voluntary asymptomatic patients including 62 men (52.5%) with a mean age of 25.6 years±4.4 (19-39). The following parameters: pelvic version (PV), pelvic incidence (PI), lumbar lordosis (LL), sacral slope (SS), hip flexion, intrinsic (IER) and extrinsic (EER) extension reserve were measured using EOS imaging™ in the reference standing position and the lunge position. The radiological signs of FAI (cam, pincer, mixed) were identified on these acquisitions then separated into 2 groups. The first was the group presenting with one or more images of FAI (FAI+) and the second group with no images of FAI (FAI-). RESULTS: There were 143 hips in the FAI+ group compared to 93 hips in the FAI- group. There were 36.4% cams and 45% pincers. With an average of 9.08°±7.81 (-11.0; 27.0) versus 12.33°±8.94 (-5.0; 55.0), the PV was significantly lower (p=0.022) in the FAI+ group compared to the FAI- group. A post-hoc power analysis on the primary outcome (PV) confirmed sufficient power (1-ß=0.809). Compared to the FAI- group, the cam group presented a significantly lower IER and EER (respectively p=0.014 and p=0.047). The comparative analysis between the FAI- and pincer groups found a significant difference in PI (p=0.001), PV (p<0.001), IER (p=0.017) and hip flexion (p<0.001), SS in lunge position (p=0.031) and EER (p=0.039). CONCLUSION: Asymptomatic subjects with radiographic signs of FAI present with weak pelvic version when standing. This pelvic hyper-anteversion is mainly found in the event of a radiological pincer sign. LEVEL OF EVIDENCE: III, retrospective comparative study.

Autologous osteochondral transplantation for focal femoral condyle defects: Comparison of mosaicplasty by arthrotomy vs. arthroscopy.

BACKGROUND: While many studies have reported the outcomes of open mosaicplasty, data on arthroscopic mosaicplasty are scarce. Only two cadaver studies have compared arthrotomy and arthroscopy. Moreover, the patello-femoral joint, which is the main donor site, has never been assessed using a specific functional score. The objective of this in vivo study was to compare arthrotomy and arthroscopy for mosaicplasty using both a global functional knee score and a specific score of the patello-femoral joint. HYPOTHESIS: The arthroscopic technique results in better functional patello-femoral outcomes. MATERIAL AND METHODS: We retrospectively compared two groups of 17 patients who underwent mosaicplasty for focal condylar cartilage defects, at our department between 2009 and 2019. Functional outcomes were assessed using the Kujala score and the Lysholm score, at least 1 year after surgery. The return to sports was assessed using the Tegner score. RESULTS: Mean follow-up was 67.4±15.9 months in the arthrotomy group and 45.2±35.1 months in the arthroscopy group (p<0.01). Cartilage defect size was similar in the two groups (arthrotomy: 1.21±0.91cm2; arthroscopy: 0.92±1.23cm2; p=0.052). The mean Kujala score was 85±21.3 in the arthrotomy group and 91.9±13.7 in the arthroscopy group (p=0.064). The mean Lysholm score was 83.9±19.8 with arthrotomy and 89.5±14.9 with arthroscopy (p=0.1). The Kujala score was greater than 95 in 4 (26%) arthrotomy patients and 13 (81%) arthroscopy patients (p=0.003). The Lysholm score was higher than 95 in 4 (26%) arthrotomy patients and 12 (75%) arthroscopy patients (p=0.012). No patient underwent surgical revision for autograft failure. DISCUSSION: This is the first clinical study comparing arthrotomy and arthroscopy for mosaicplasty. Clinical outcomes were good with both techniques. The proportion of patients with excellent Lysholm and Kujala functional scores was significantly higher in the arthroscopy group than in the arthrotomy group. This result may be ascribable to decreased donor-site morbidity obtained with arthroscopy. LEVEL OF EVIDENCE: IV, retrospective observational comparative study.

Outcomes and survival of a modern dual mobility cup and uncemented collared stem in displaced femoral neck fractures at a minimum 5-year follow-up.

INTRODUCTION: The choice of implant type for total hip replacement in the treatment of femoral neck fractures remains debated. Some authors advocate for the systematic use of cemented stems, while others do not use dual mobility first-line. We therefore conducted a retrospective study using a dual mobility cup (DMC) and an uncemented collared stem (UCS) in order to: (1) confirm the low dislocation rate in this indication, (2) assess other surgical complications, in particular periprosthetic fractures, (3) ensure that these benefits are maintained over time, at a minimum follow-up of 5 years and, (4) assess the rate of revision of the implants. HYPOTHESIS: Our hypothesis was that the dual mobility dislocation rate for the treatment of femoral neck fractures was lower than for bipolar hemiarthroplasties or single mobility hip prostheses. PATIENTS AND METHODS: A retrospective study of 244 femoral neck fractures (242 patients) treated with DMC and UCS was conducted, between 2013 and 2014. The mean age was 83±10 years (60-104). The occurrence of dislocation, periprosthetic fracture, infection of the surgical site, loosening, reoperation and revision were investigated. The HOOS Joint Replacement (JR) score was collected. The cumulative incidence with mortality was used as a competing risk. RESULTS: The mean follow-up was 6 years±0.5 (5-7). At the last follow-up, 108 patients (50%) had died. Twenty-three patients (9.5%) were lost to follow-up. One case of symptomatic aseptic loosening of DMC was observed. The cumulative incidence of dislocations and periprosthetic fractures at 5 years were 2% (95% CI: 0.9-5.4) and 3% (95% CI: 1.2-6), respectively. The 5-year cumulative incidence of surgical site infections was 3.5% (95% CI: 1.8-7). The cumulative incidence of reoperations at 5 years was 7% (95% CI: 4.5-11). The causes of reoperation were periprosthetic fracture (n=6), infection (n=8), postoperative hematoma (n=2) and cup malposition (n=2). The cumulative incidence of a revision at 5 years was 2.7% (95% CI: 1.2-6). The cumulative incidence of a surgical complication from any cause at 5 years was 9% (95% CI: 6.7-14.8). The mean HOOS JR score was 79±5 (52-92). DISCUSSION: The cumulative incidence of dislocation at 5 years is low and other surgical complications (including periprosthetic fractures) do not increase during this period for DMC associated with UCS, in femoral neck fractures. The use of this type of implant is reliable in the treatment of femoral neck fractures. LEVEL OF EVIDENCE: IV; retrospective study without control group.

Improved sizing with image-based robotic-assisted system compared to image-free and conventional techniques in medial unicompartmental knee arthroplasty.

AIMS: Ideal component sizing may be difficult to achieve in unicompartmental knee arthroplasty (UKA). Anatomical variants, incremental implant size, and a reduced surgical exposure may lead to over- or under-sizing of the components. The purpose of this study was to compare the accuracy of UKA sizing with robotic-assisted techniques versus a conventional surgical technique. METHODS: Three groups of 93 medial UKAs were assessed. The first group was performed by a conventional technique, the second group with an image-free robotic-assisted system (Image-Free group), and the last group with an image-based robotic arm-assisted system, using a preoperative CT scan (Image-Based group). There were no demographic differences between groups. We compared six parameters on postoperative radiographs to assess UKA sizing. Incorrect sizing was defined by an over- or under-sizing greater than 3 mm. RESULTS: There was a higher rate of tibial under-sizing posteriorly in the conventional group compared to robotic-assisted groups (47.3% (n = 44) in conventional group, 29% (n = 27) in Image-Free group, 6.5% (n = 6) in Image-Based group; p < 0.001), as well as a higher rate of femoral under-sizing posteriorly (30.1% (n = 28) in conventional group, 7.5% (n = 7) in Image-Free group, 12.9% (n = 12) in Image-Based group; p < 0.001). The posterior femoral offset was more often increased in the conventional group, especially in comparison to the Image-Based group (43% (n = 40) in conventional group, 30.1% (n = 28) in Image-Free group, 8.6% (n = 8) in Image-Based group; p < 0.001). There was no significant overhang of the femoral or tibial implant in any groups. CONCLUSION: Robotic-assisted surgical techniques for medial UKA decrease the risk of tibial and femoral under-sizing, particularly with an image-based system using a preoperative CT scan. Cite this article: Bone Joint J 2021;103-B(4):610-618.