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.

What happens to endoscopic/arthroscopic tenotomies with iliopsoas impingement in the medium term? Review of a prospective cohort of 64 patients with a minimum follow-up of 5 years.

INTRODUCTION: The occurrence of iliopsoas impingement (IPI) after total hip arthroplasty (THA) is a proven risk factor for negative outcomes. Endoscopic or arthroscopic tenotomies of the iliopsoas offer a surgical solution with short-term results that have already been validated in prospective multicenter series. We carried out a review of the patients at more than 5 years of follow-up in order to assess the stability of the results over time. HYPOTHESIS: Our main hypothesis was that endoscopic/arthroscopic tenotomies allow stable medium-term resolution of the painful symptoms of IPI. Our secondary hypothesis was that medium-term survival was satisfactory. MATERIAL AND METHOD: This study is a continuation of a multicenter prospective series. Patients were contacted through multiple channels in order to: obtain an Oxford score, assess for satisfaction, psoas irritation, and daily pain on a visual analogue scale (VAS). RESULTS: Of 64 patients in the original study, 57 were contacted. The Oxford score at the last follow-up was 40.7±7.7 [12-48]. There was a significant difference between the Oxford scores preoperatively, at 8 months and at the last follow-up. The mean satisfaction out of 10 was 8.0±2.1 [1-10]. We found 84% satisfaction at 5 years against 83% at 8 months. The VAS was 2.1±2.3 [0-10]. A straight leg psoas sign was present in 19.6% (10/51) of patients at 5 years, compared to 15.6% (8/51) at 8 months. The sign disappeared in four cases, while it reappeared during the interval in six cases. Survival was 91.2% (95% CI: 80.2-96.3) at 5 years. CONCLUSION: Endoscopic/arthroscopic iliopsoas tenotomies represent a permanent medium-term solution to treat IPI after THA. The existence of a force differential or an acetabular overhang does not seem, within a certain limit, to impact the results in the medium term. LEVEL OF EVIDENCE: IV; prospective series without control group.

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.

Labral tears in hip dysplasia and femoroacetabular impingement: A systematic review.

INTRODUCTION: Hip dysplasia and femoroacetabular impingement are pathologies whose impact on the function and survival of the hip joint is no longer debated. Labral tears may be present and impact the prognosis of the causal pathology. Labral tear management lacks consensus and still raises several questions, thus we conducted a systematic analysis to clarify: 1) What is its prevalence in hip dysplasia and femoroacetabular impingement? 2) Does it modify the symptomatology of the causal pathology? 3) Is its repair better than resection or abstention? MATERIAL AND METHOD: A systematic literature review was carried out following the PRISMA guidelines, using the Medline and Embase databases and including all articles in French or English, written until June 2022 referring to labral tears in hip dysplasia and femoroacetabular impingement. The articles were analyzed by 2 surgeons in order to select them according to a predefined algorithm. 1) Articles were selected by title from the search results. 2) A selection based on the abstract was then made. 3) A final selection was made upon complete reading. 4) In the event of a discrepancy during the selection, a third co-author was contacted for a final decision. 5) Data extraction was then carried out by the two readers using a preformatted sheet. RESULTS: Of the 1177 articles identified, 43 articles were kept for the final analysis. The prevalence of labral tears was on average 78.80±4.7% [17 to 100%] in dysplasia and 93.8±16.8% [33% to 100%] in impingement. The review did not reveal any symptomatology specific to the labral tear. In dysplasia, 5 comparative studies were analyzed. A single study on shelf arthroplasties demonstrated the negative impact of a labral tear in the event of resection on survival compared to no tear (83% versus 15.2% (p=0.048)). Regarding impingements, 8 comparative studies were analyzed. At 7 years of follow-up, only one study found a significant and clinically relevant functional gain in terms of MCID (minimal clinically important difference) for labral repair compared to debridement on the mHHS score (p=0.008), SF-12 score (p=0.012), and pain scale (p=0.002). One study showed superiority of repair over labral debridement in terms of 10-year survival (78% 95% CI [64-92%] vs 46% 95% CI [26-66%] (p=0.009)). DISCUSSION: The literature analysis was heterogeneous with a few comparative studies and predominantly short periods of follow-up. Understanding labral pathology and its impact requires differentiating between the different tear categories and proposing treatment to restore or preserve the biomechanical properties of the joint. LEVEL OF EVIDENCE: IV, Systematic Review of Level 1-4 Evidence.

Proximal femoral anatomy and collared stems in hip arthroplasty: is a single collar size sufficient?

BACKGROUND: Even if the benefits of collars are unclear, they remain widely used, in several femoral stem designs. This study aimed to determine whether collar size should be proportional to hip dimensions and morphology. The hypothesis was that the collar should be larger for greater stem sizes and for varus femoral necks. METHODS: Computed Tomography scans of 204 healthy hips were digitally analysed and manually templated to determine principle dimensions, appropriate stem size and model, as well as cortical distance at the femoral calcar (ideal collar size). RESULTS: Univariable analysis revealed that cortical distance was moderately correlated with mediolateral offset (r = 0.572; p < 0.0001) and stem model (r = 0.520; p < 0.0001). Cortical distance was weakly correlated with head diameter (r = 0.399; p < 0.0001), stem size (r = 0.200; p = 0.017), and patient gender (r = 0.361; p < 0.0001). Multivariable analysis confirmed that stem model (p < 0.0001) and head diameter (p = 0.0162) are directly correlated to cortical distance. CONCLUSION: We found that cortical distance along the femoral calcar is directly correlated with the model of the stem implanted ('standard' or 'varus') and with the head diameter. This cortical distance indicates optimal collar size, which would grant maximum calcar coverage without prosthetic overhang. Collar size should be proportional to the size of the operated hip, and should be larger for 'varus' stem models than for 'standard' stem models.

Hip pain from impingement and dysplasia in patients aged 20-50 years. Workup and role for reconstruction.

In the 20-50-year age group, hip pain usually indicates dysplasia. Chronic mechanical pain is the usual pattern, although acute pain caused by avulsion or degeneration of the labrum may occur. The morphological characteristics of the dysplastic hip should be evaluated, and the link between the dysplasia and the osteoarthritis should be confirmed. Three factors indicate a favorable prognosis: joint space preservation, age younger than 40 years, and correctable femoral and acetabular abnormalities. Reconstruction is highly desirable, as it delays the need for joint replacement by 20 years. After 15 years, good outcomes are seen in 87% of patients after shelf arthroplasty and 85% after femoral varus osteotomy with or without shelf arthroplasty. Chiari acetabular osteotomy can be performed in patients with osteoarthritis but is followed by prolonged limping. Periacetabular osteotomy should be reserved for patients with moderate dysplasia and no evidence of osteoarthritis. Shelf arthroplasty and femoral osteotomy require 5-8 months off work (compared to 5 months after hip replacement surgery) but subsequently permits a far more active lifestyle. Hip replacement, which is required 20 years or more after biologic reconstruction, carries the same prognosis as first-line hip replacement (good results in 80% of patients after 15 years). Acute sharp pain related to anterior hip derangement also occurs in primary femoroacetabular impingement (FAI). The most common pattern is cam impingement, which is due to a decrease in head-neck offset and manifests as pain during flexion and adduction of the hip. Cam impingement can be corrected by anterolateral osteoplasty, which is often performed arthroscopically. Pincer-type impingement is contact between the anterior acetabular rim and the femoral neck due to retroversion of the proximal acetabulum. The imaging study strategy is discussed. Coxometry, computed tomography, and arthrography can be used. Primary FAI, which occurs as a result of geometric abnormalities, should be distinguished from secondary impingement. Causes of secondary impingement include exaggerated lumbar lordosis with pelvic tilt and to hip osteophytosis (sports or posterior hip osteoarthritis). Osteoplasty is rarely appropriate in patients with secondary impingement. The features of acute anterior hip derangement are now better defined. They can be used to guide palliative treatment, which is effective, in the medium term at least. Experience acquired over the last two decades has established the efficacy of surgery for hip dysplasia.

Can rotation osteotomy remain effective for more than ten years?

Trochanteric rotation osteotomies displace the necrotic zone of the femoral head outside the major acetabular weight-bearing zone and rotate the head anteriorly or posteriorly. Nineteen consecutive patients were selected for rotation osteotomy based on age,absence of progressive disease, and preoperative imaging studies predicting that rotation osteotomy would move the entire necrotic zone away from the acetabular roof. Factors associated with failure were head flattening and necrosis deeper than one third of the femoral head diameter. Among patient subsets with identical disease stages, outcomes seemed better after posterior rotation than after anterior rotation. Rotation osteotomies,fixed by a nail plate, can be recommended in a few selected patients with shallow necrosis involving less than one third of the femoral head diameter and without osteoarthritis or head flattening. Under these conditions, good outcomes may be achieved for 10 years or longer.