Pincer-type Femoroacetabular Impingement Research Articles

Mid-term results of autologous matrix-induced chondrogenesis for large chondral defects in hips with femoroacetabular impingement syndrome.

The purpose of this study was to evaluate the mid-term outcomes of autologous matrix-induced chondrogenesis (AMIC) for the treatment of larger cartilage lesions and deformity correction in hips suffering from symptomatic femoroacetabular impingement (FAI). This single-centre study focused on a cohort of 24 patients with cam- or pincer-type FAI, full-thickness femoral or acetabular chondral lesions, or osteochondral lesions ≥ 2 cm2, who underwent surgical hip dislocation for FAI correction in combination with AMIC between March 2009 and February 2016. Baseline data were retrospectively obtained from patient files. Mid-term outcomes were prospectively collected at a follow-up in 2020: cartilage repair tissue quality was evaluated by MRI using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported outcome measures (PROMs) included the Oxford Hip Score (OHS) and Core Outcome Measure Index (COMI). Clinical examination included range of motion, impingement tests, and pain. A total of 12 hips from 11 patients were included (ten males, one female, mean age 26.8 years (SD 5.0), mean follow-up 6.2 years (SD 5.2 months)). The mean postoperative MOCART score was 66.3 (SD 16.3). None of the patients required conversion to total hip arthroplasty. Two patients had anterior impingement. External hip rotation was moderately limited in four patients. There was a correlation between MOCART and follow-up time (rs = -0.61; p = 0.035), but not with initial cartilage damage, age, BMI, or imaging time delay before surgery. PROMs improved significantly: OHS from 37.4 to 42.7 (p = 0.014) and COMI from 4.1 to 1.6 (p = 0.025). There was no correlation between MOCART and PROMs. Based on the reported mid-term results, we consider AMIC as an encouraging treatment option for large cartilage lesions of the hip. Nonetheless, the clinical evidence of AMIC in FAI patients remains to be determined, ideally in the context of randomized controlled trials.

Acetabular Rim Disorders: Epidemiology, Etiology, Management, and Outcomes.

» Anatomic disorders of the acetabular rim are a common, correctable source of hip pain in younger patients.» Some common conditions of involving abnormal acetabular rim morphology include developmental dysplasia of the hip, pincer-type femoroacetabular impingement, acetabular protrusion, and acetabular retroversion.» Treatment option for these conditions were historically limited to open osteotomy and osteoplasty procedures; however, there is increasing use of arthroscopic intervention for these patients.» Arthroscopic intervention has demonstrated short-term success in a variety of focal acetabular rim disorders; however, further research is needed to determine the long-term outcomes of these procedures and their utility in more global pathology.

Sex differences in the anatomy of the anterior–superior acetabular rim in relation to pincer-type femoroacetabular impingement in Koreans: a three-dimensional quantitative analysis

PurposeThe aim of this study was to compare the anatomical structures of the acetabular rim around the anterior inferior iliac spine (AIIS) ridge that indicate anterior focal coverage of acetabulum between the sexes using a three-dimensional (3D) model.Methods3D models of 71 adults (38 men and 33 women) with normal hip joints were used. Based on the location of the inflection point (IP) of the acetabular rim around the AIIS ridge, the patients were classified into anterior and posterior types, and the ratios thereof for each sex were compared. Coordinates for the IP, the most anterior point (MAP), and the most lateral point (MLP) were obtained and compared between the sexes and between anterior and posterior types.ResultsCoordinates for IPs in men were located anterior and inferior to those in women. MAP coordinates for men were located inferior to those for women, and MLP coordinates for men were located lateral and inferior to those for women. Comparing AIIS ridge types, we noted that coordinates for IPs of the anterior type were located medial, anterior, and inferior to those of the posterior type. Meanwhile, MAP coordinates of the anterior type were located inferior to those of the posterior type, and MLP coordinates of the anterior type were located lateral and inferior to those of the posterior type.ConclusionAnterior focal coverage of the acetabulum appears to differ between the sexes, and this difference may affect the development of pincer-type femoroacetabular impingement (FAI). Additionally, we found that anterior focal coverage differs according to anterior or posterior positioning of the bony prominence around the AIIS ridge, which may affect development of FAI.

Femoral impingement in maximal hip flexion is anterior-inferior distal to the cam deformity in femoroacetabular impingement patients with femoral retroversion

Femoroacetabular impingement (FAI) patients report exacerbation of hip pain in deep flexion. However, the exact impingement location in deep flexion is unknown. The aim was to investigate impingement-free maximal flexion, impingement location, and if cam deformity causes hip impingement in flexion in FAI patients. A retrospective study involving 24 patients (37 hips) with FAI and femoral retroversion (femoral version (FV) < 5° per Murphy method) was performed. All patients were symptomatic (mean age 28 years (SD 9)) and had anterior hip/groin pain and a positive anterior impingement test. Cam- and pincer-type subgroups were analyzed. Patients were compared to an asymptomatic control group (26 hips). All patients underwent pelvic CT scans to generate personalized CT-based 3D models and validated software for patient-specific impingement simulation (equidistant method). Mean impingement-free flexion of patients with mixed-type FAI (110° (SD 8°)) and patients with pincer-type FAI (112° (SD 8°)) was significantly (p < 0.001) lower compared to the control group (125° (SD 13°)). The frequency of extra-articular subspine impingement was significantly (p < 0.001) increased in patients with pincer-type FAI (57%) compared to cam-type FAI (22%) in 125° flexion. Bony impingement in maximal flexion was located anterior-inferior at femoral four and five o'clock position in patients with cam-type FAI (63% (10 of 16 hips) and 37% (6 of 10 hips)), and did not involve the cam deformity. The cam deformity did not cause impingement in maximal flexion. Femoral impingement in maximal flexion was located anterior-inferior distal to the cam deformity. This differs to previous studies, a finding which could be important for FAI patients in order to avoid exacerbation of hip pain in deep flexion (e.g. during squats) and for hip arthroscopy (hip-preservation surgery) for planning of bone resection. Hip impingement in flexion has implications for daily activities (e.g. putting on shoes), sports, and sex.Cite this article: Bone Joint Res2023;12(1):22-32.

Can modified Dunn radiographs be an alternative to standing AP pelvis radiographs in the evaluation of pincer femoroacetabular impingement?

The purpose of this study was to compare modified Dunn radiographs with standing anteroposterior (AP) pelvis radiographs in respect of the tilt ratio, lateral centre-edge angle (LCEA), crossover sign, crossover percentage and joint space width measurements. The study hypothesis was that modified Dunn radiographs could be an alternative method to standing AP pelvis images in the evaluation of pincer-type femoroacetabular impingement (FAI). The study included 31 patients with a mean age of 42 years (range: 29-55 years) who had modified Dunn and standing AP pelvis radiographs taken in the radiological evaluation of non-traumatic hip pain between July 2018 and September 2022. Similar tilt ratio values were obtained on standing AP and modified Dunn images (P = 0.986). Joint space width showed a decrease in the transition from the modified Dunn position to the standing position, but the difference was not statistically significant (P = 0.161). The mean LCEA was measured as 34° ± 4° in the standing position and as 35° ± 5° in the modified Dunn position. No statistically significant difference was determined in the number of patients with a crossover sign or the crossover percentage values in these patients (P > 0.05). The data obtained in this study showed that there was no significant difference between images taken in the standing and modified Dunn positions in respect of radiological findings of pelvic tilt and pincer-type FAI. The modified Dunn radiograph is equivalent to the standing AP pelvis radiograph for the evaluation of pincer FAI.

Results of Arthroscopic Treatment for Femoroacetabular Impingement

Background. Femoroacetabular impingement (FAI) is one of the most frequent causes of hip pain and limited hip mobility in young and middle-aged patients. It is a result of repeated injury of hip structures, that leads to degenerative changes in hip labrum, cartilage and subchondral bone and provokes progressive development of hip osteoarthritis.&#x0D; Aim of study to analyze own experience of treating patients with femoroacetabular impingement and identify factors affecting its outcomes.&#x0D; Methods. Retrospective, uncontrolled, single-center clinical study included 128 patients with FAI which had 150 surgeries on 149 joints in in the period from 2013 to 2021. All patients underwent physical examination and X-ray diagnostics, their FAI type was identified. The alpha angle of external part of femoral head in anterior-posterior position and in the modified Dunn 45 position, as well as Tonnis angle, lateral central-marginal angle in Ogata modification and the height of articular gap along the lateral (LS) and medial edges (MS) of sclerosed acetabulum part were calculated. The i-HOT-33 and HOS scales were used to assess preoperative status and postoperative results.&#x0D; Results. The average follow-up period was 3.9 years (SD 1.71; min 1.05 and max 8.16). The study included 55 (43.0%) women and 73 (57.0%) men which underwent 64 (42.7%) and 86 (57.3%) surgeries respectively. The most common types of FAI, according to our data, were mixed type (53% of joints) and сam type (27.5% of joints). Insufficient coverage of the femoral head by the acetabulum (borderline dysplasia) in combination with the сam deformity of the femoral head was observed in 18.1%. Pincer-type FAI was observed in 1.4% of joints. We obtained the worst results with a combination of сam deformity and borderline dysplasia in comparison with cam- and mix-type FAI according to the i-HOT-33 and HOS scales. Patients age, deep cartilage damage, irreparable labrum damage and height decrease of the lateral part of the articular gap determined negative effect on treatment results according to the i-HOT-33 and HOS scales.&#x0D; Conclusion. Hip arthroscopy showed good short- and midterm outcomes in patients with FAI. Pain syndrome is most often manifested in patients with pathology of hip soft tissue structures concomitant to FAI. The combination of сam deformity and insufficient femoral head coverage, deep cartilage damage and a height decrease of the articular gap are important predictors of poor treatment results.

Reliability of simple radiographic signs in detecting pincer-type femoroacetabular impingement

Reliability of simple radiographic signs in detecting pincer-type femoroacetabular impingement

How frequent is absolute femoral retroversion in symptomatic patients with cam- and pincer-type femoroacetabular impingement?

AimsThe frequency of severe femoral retroversion is unclear in patients with femoroacetabular impingement (FAI). This study aimed to investigate mean femoral version (FV), the frequency of absolute femoral retroversion, and the combination of decreased FV and acetabular retroversion (AR) in symptomatic patients with FAI subtypes.MethodsA retrospective institutional review board-approved observational study was performed with 333 symptomatic patients (384 hips) with hip pain due to FAI evaluated for hip preservation surgery. Overall, 142 patients (165 hips) had cam-type FAI, while 118 patients (137 hips) had mixed-type FAI. The allocation to each subgroup was based on reference values calculated on anteroposterior radiographs. CT/MRI-based measurement of FV (Murphy method) and AV were retrospectively compared among five FAI subgroups. Frequency of decreased FV < 10°, severely decreased FV < 5°, and absolute femoral retroversion (FV < 0°) was analyzed.ResultsA significantly (p < 0.001) lower mean FV was found in patients with cam-type FAI (15° (SD 10°)), and in patients with mixed-type FAI (17° (SD 11°)) compared to severe over-coverage (20° (SD 12°). Frequency of decreased FV < 10° was significantly (p < 0.001) higher in patients with cam-type FAI (28%, 46 hips) and in patients with over-coverage (29%, 11 hips) compared to severe over-coverage (12%, 5 hips). Absolute femoral retroversion (FV < 0°) was found in 13% (5 hips) of patients with over-coverage, 6% (10 hips) of patients with cam-type FAI, and 5% (7 hips) of patients with mixed-type FAI. The frequency of decreased FV< 10° combined with acetabular retroversion (AV < 10°) was 6% (8 hips) in patients with mixed-type FAI and 5% (20 hips) in all FAI patients. Of patients with over-coverage, 11% (4 hips) had decreased FV < 10° combined with acetabular retroversion (AV < 10°).ConclusionPatients with cam-type FAI had a considerable proportion (28%) of decreased FV < 10° and 6% had absolute femoral retroversion (FV < 0°), even more for patients with pincer-type FAI due to over-coverage (29% and 13%). This could be important for patients evaluated for open hip preservation surgery or hip arthroscopy, and each patient requires careful personalized evaluation.Cite this article: Bone Jt Open 2022;3(7):557–565.

Treatment of Severe Pincer-Type Femoroacetabular Impingement With Arthroscopic Significant Acetabular Rim Correction and Circumferential Labral Reconstruction Improves Patient-Reported Outcome Measures

To validate an arthroscopic approach for performing significant acetabular rim correction and circumferential labral reconstruction required to treat severe pincer-type femoroacetabular impingement. Using a minimum of 2-year follow-up, data from 48 hips, including 47 patients (11 male, 36 female; mean age of 42 years) having undergone significant arthroscopic acetabuloplasty for severe pincer impingement (center edge angle >45°) with concomitant circumferential allograft labral reconstruction were analyzed to determine improvements in patient-reported outcomes and degree of radiographic correction. Findings demonstrated a 98% success rate, including substantial improvements on all radiographic measurements and patient-reported outcomes. Minimal clinically important differences were met with extremely strong measures of effect. The mean center edge angle improved from 49° to 36° (MΔ= 13.96, P ≤ .001, standard deviation [SD]= 55.97, confidence interval [CI] 12.17- 15.62, d= 2.33) and the mean Tönnis angle improved from -6° to 0° (MΔ= 6.2, P ≤ .001, SD= 2.76 CI -7.1 to -5.39, d= 2.29). Modified Hip Harris Scores improved by a mean of 34.45 points (P ≤ .001, SD= 20.64, 95% CI 28.45-40.44, d= 1.66). Lower extremity functional scale scores improved by a mean of 27.35 points (P ≤ .001, SD= 18.37, 95% CI 22.02-32.69, d=1.48). No complications were reported. One case converted to a total hip arthroplasty (2%). Findings validated that the significant acetabular rim correction required to treat severe pincer morphology is safe and feasible via an arthroscopic approach. This, in addition to concomitant circumferential allograft labral reconstruction, resulted in improvement in patient-reported outcomes and radiographic measurements. Level IV, therapeutic case-series.

PINCER MORPHOLOGY IS NOT ASSOCIATED WITH DEVELOPMENT OF HIP OSTEOARTHRITIS WITHIN 10 YEARS; A NATIONWIDE PROSPECTIVE COHORT STUDY (CHECK)

Purpose: Pincer morphology is an overcoverage of the acetabulum relative to the femoral head (figure 1). During motion of the hip, this might lead to an abutment between the acetabular rim and femoral head-neck junction, a process referred to as pincer-type femoroacetabular impingement. This abnormal contact between the femoral head and acetabulum might potentially lead to damage of the labrum and articular cartilage. However, to date, results on the relationship between pincer morphology and hip osteoarthritis (OA) have been conflicting and previous prospective cohort studies typically did not find an association.

Femoroacetabular impingement in the unpinned contralateral hip in patients with primary unilateral slipped capital femoral epiphysis: preliminary radiographic outcomes.

The study evaluated femoroacetabular impingement (FAI) in the unpinned contralateral hip in patients with unilateral slipped capital femoral epiphysis (SCFE) and verified initial age, posterior sloping angle (PSA) and center-edge angle (CEA) as predictors of FAI in the contralateral hip. 152 patients with unilateral SCFE with a mean index age of 13.2 years (8.2-17.2 years) were enrolled retrospectively into the study. Mean follow-up was 8 years (3-14 years). PSA and CEA were measured on initial radiographs of the unaffected hip. Alpha-angle and CEA were measured on radiographs taken at the last follow-up to identify FAI. Four groups of patients were distinguished: (1) no FAI (10 patients, 17.54%); (2) CAM-type FAI (41 patients, 71.9%); (3) pincer-type FAI (3 patients, 5.26%) and (4) mixed-type FAI (13 patients, 22.8%). The mean PSA was 12.1°, 12°, 16.8°, 11.9° for groups 1, 2, 3 and 4, respectively, with no significant difference ( P = 0.65). The mean initial CEA for groups 1, 2, 3 and 4 was 34.4°, 35.5°, 42° and 42° respectively, with significant differences between groups 1 versus 4 ( P = 0.034) and 2 versus 4 ( P = 0.009). Conclusions are as follows: 1. Radiographic features of FAI were present in 85.1% of unpinned contralateral hips in patients with unilateral SCFE. 2. 71.9% of unpinned contralateral hips developed CAM deformity. 3. CEA can be used in predicting pincer-type FAI in the contralateral hip in unilateral SCFE. 4. PSA and age revealed negligible value in predicting FAI.

Arthroscopic assisted mini-open arthrotomy for the treatment of the femoroacetabular impingement

Treatment of pathologies of the central and peripheral compartment of the hip using arthroscopic assisted mini-open arthrotomy via the Smith-Petersen approach. Cam- and pincer-type femoroacetabular impingement (FAI), labral tear, loose bodies. Osteoarthritis of the hip with Tönnis classification grade ≥ 2. After mini-open approach to the hip joint via direct anterior muscular gap, the anterior capsule is split with protection of the labrum. Decompression allows the joint to be inspected using an arthroscope. Depending on the intra-articular findings, additional procedures can be performed (e.g., curettage of the cartilage, microfracturing, matrix-induced autologous chondrocyte implantation [MACI]). Cases with pincer-type FAI or labral tear can also be addressed. After partial release, the cam-type FAI can be resected using asurgical burr. Partial weightbearing for 2-6weeks with 10-20 kg or half body weight using crutches depending on the intraoperative treatment. Radiological analysis of the pre- and postoperative X‑rays (n = 69) prove that this surgical technique is suitable to address pathologies especially FAI syndromes. The α‑angle according to Nötzli could be reduced from amean preoperative value of 72.8° to 49.4° postoperative. In combined cam-type and Pincer-type FAI syndrome (n = 16), the lateral center-edge angle could be reduced from amean preoperative value of 50.2° to 37.6° postoperatively. The clinical follow-up (n = 29) revealed good midterm outcomes after arthroscopic assisted mini-open arthrotomy (modified Harris Hip Score [mHHS] 84.8points after 4.9years [range 4.2-5.7; ±0.43]).

Ultrasound and shear-wave elastography characteristics of the iliocapsularis muscle in pincer-type femoroacetabular impingement.

The iliocapsularis muscle is a structure of the anterior hip, which may play a key role in stabilizing the hip joint, but to our knowledge no studies exist describing ultrasound (US) and shear-wave characteristics of this muscle. To investigate the anatomic dimensions and elasticity of the iliocapsularis muscle in patients with pincer-type femoroacetabular impingement (FAI) and normal hips using gray-scale US and shear-wave elastography (SWE). Case-control study. Sports medicine and ultrasound department within a tertiary hospital. Thirty-three patients (33 hips) with pincer-type FAI and 37 healthy volunteers (37 hips). Not applicable. US parameters (anteroposterior diameter, transverse diameter and circumference) of the iliocapsularis muscle in patients with pincer-type FAI and volunteers. Shear-wave velocity and Young's modulus of the iliocapsularis muscle in patients with pincer-type FAI and volunteers in both neutral and external rotation positions. Significant differences were not observed in the anatomic dimensions of the iliocapsularis muscle between patients with pincer-type FAI and volunteers. The iliocapsularis muscle in patients with pincer-type FAI had significantly lower shear-wave velocity and Young's modulus than the volunteers (p < .05). The cutoff value of the maximum velocity in the external rotation position was 3.35 m/s, which separated pincer-type FAI patients from volunteers and revealed the highest accuracy with sensitivity, specificity, and accuracy of 78.8%, 48.6%, and 64.3%, respectively. The anatomic dimensions of the iliocapsularis muscle in pincer-type FAI patients and volunteers were similar; however, iliocapsularis stiffness in patients with pincer-type FAI was significantly lower than that of the volunteers. SWE can demonstrate altered muscle stiffness of the iliocapsularis muscle in pincer-type FAI patients, which might be used to help make clinical decisions.

Lower pelvic tilt, lower pelvic incidence, and increased external rotation of the iliac wing in patients with femoroacetabular impingement due to acetabular retroversion compared to hip dysplasia.

AimsThe effect of pelvic tilt (PT) and sagittal balance in hips with pincer-type femoroacetabular impingement (FAI) with acetabular retroversion (AR) is controversial. It is unclear if patients with AR have a rotational abnormality of the iliac wing. Therefore, we asked: are parameters for sagittal balance, and is rotation of the iliac wing, different in patients with AR compared to a control group?; and is there a correlation between iliac rotation and acetabular version?MethodsA retrospective, review board-approved, controlled study was performed including 120 hips in 86 consecutive patients with symptomatic FAI or hip dysplasia. Pelvic CT scans were reviewed to calculate parameters for sagittal balance (pelvic incidence (PI), PT, and sacral slope), anterior pelvic plane angle, pelvic inclination, and external rotation of the iliac wing and were compared to a control group (48 hips). The 120 hips were allocated to the following groups: AR (41 hips), hip dysplasia (47 hips) and cam FAI with normal acetabular morphology (32 hips). Subgroups of total AR (15 hips) and high acetabular anteversion (20 hips) were analyzed. Statistical analysis was performed using analysis of variance with Bonferroni correction.ResultsPI and PT were significantly decreased comparing AR (PI 42° (SD 10°), PT 4° (SD 5°)) with dysplastic hips (PI 55° (SD 12°), PT 10° (SD 6°)) and with the control group (PI 51° (SD 9°) and PT 13° (SD 7°)) (p < 0.001). External rotation of the iliac wing was significantly increased comparing AR (29° (SD 4°)) with dysplastic hips (20°(SD 5°)) and with the control group (25° (SD 5°)) (p < 0.001). Correlation between external rotation of the iliac wing and acetabular version was significant and strong (r = 0.81; p < 0.001). Correlation between PT and acetabular version was significant and moderate (r = 0.58; p < 0.001).ConclusionThese findings could contribute to a better understanding of hip pain in a sitting position and extra-articular subspine FAI of patients with AR. These patients have increased iliac external rotation, a rotational abnormality of the iliac wing. This has implications for surgical therapy with hip arthroscopy and acetabular rim trimming or anteverting periacetabular osteotomy (PAO).Cite this article: Bone Jt Open 2021;2(10):813–824.

Preoperative Alpha Angles Can Predict Severity of Acetabular Rim Chondral Damage in Symptomatic Cam-Type Femoroacetabular Impingement: A Prospective Observatory Study

To identify the relationship between the alpha angle and the severity of chondrolabral separation as well as acetabular rim chondral damage in symptomatic cam-type femoroacetabular impingement (FAI) with or without focal pincer-type FAI. Patients who received hip arthroscopy under the diagnosis of symptomatic cam-type FAI between January 2018 and August 2018 were identified in a prospectively collected database. Patients were excluded if preoperative lateral center-edge angle <25°, lateral center-edge angle ≥40°, Tönnis grade >1, with previous surgery on the affected hip, or with concomitant synovial disease. The chondrolabral junction was classified into intact chondrolabral junction, stable chondrolabral separation and unstable chondrolabral separation. The classification of acetabular rim chondral damage was modified from the MAHORN (Multicenter Arthroscopy of the Hip Outcomes Research Network) classification: normal/softening, bubble, pocket, flap, and exposed bone. The relationship between the hip morphology and severity of chondrolabral junction and acetabular rim chondral damage was assessed. A total of 71 patients with the mean age of 33.2 ± 11.0 years were included. Preoperative alpha angles on anteroposterior (AP) or Lauenstein view positively correlated with the severity of acetabular rim chondral damage (P= .028 and P= .016, respectively). A significant increment of the alpha angle between 2 consecutive grades of acetabular rim chondral damage was 7.1° (P=.001) on AP view and 5.2° on Lauenstein view (P= .001). The cut-off values for predicting advanced acetabular rim chondral damage (pocket, flap or bony exposure) were an AP alpha angle of 70° (P= .025) and a Lauenstein alpha angle of 57° (P= .003). There was no significant association between the alpha angle and the severity of chondrolabral separation. In patients with symptomatic cam-type FAI with or without focal pincer-type FAI, greater preoperative alpha angles on AP and Lauenstein views can predict more severe acetabular chondral damage. Level III.

The lateral joint space width is essential for the outcome after arthroscopically assisted mini-open arthrotomy for treatment of a femoroacetabular impingement: an analysis of prognostic factors for the success of this hip-preserving technique.

The purpose of this study was to analyze predicting factors for a conversion to a total hip replacement (THR) after mini-open arthrotomy for treatment of femoroacetabular impingement (FAI). Between 2011 and 2016, we identified 32 patients, who were treated for FAI with a mini-open arthrotomy and received after mean time of 2.1 ± 1.4years a THR. These patients were compared to 47 cases who did not receive a THR (mean follow-up: 4.3 ± 0.7years) to explore pre- and intra-operative factors associated with a conversion to THR. The results were presented in separated Kaplan-Meier curves with log rank test for significance and hazard ratios. A lateral joint space width of > 4mm showed a higher THR-free survival rate compared to < 4mm (p = 0.001); analogously one-sided (acetabular/femoral) 3-4° cartilage damage had a comparable THR-free survival rate than 1-2° kissing lesions (p = 0.001). Furthermore, an intact labrum without treatment and good cartilage status, a refixed labrum after rim resection in case of a pincer type FAI, or a refixed teared labrum were associated with a longer THR-free time than an untreated labrum accompanied by a poor cartilage status or an ossified labrum (p = 0.002). The strongest independent factor for a conversion to THR was femoral cartilage damage grade 1 and higher (p = 0.046). However, the rate of available patients was 53.0%. The success of a joint-preserving mini-open arthrotomy seems to be dependent on the status of the radiological joint space width and the intra-operative cartilage status of the lateral edge.

Sex differences in the prevalence of radiographic findings of structural hip deformities in patients with symptomatic femoroacetabular impingement.

ABSTRACTThe purpose of this study was to determine the sex differences in the overall prevalence of radiographic femoroacetabular impingement (FAI) deformity patients presenting with hip pain and to identify the most common radiographic findings in male and female patients. A geographic database was used to identify patients between the age of 14 and 50 years with hip pain from 2000 to 2016. A chart and radiographic review was performed to identify patients with cam, pincer and mixed-type FAI. A total of 374 (449 hips) out of 612 (695 hips) male patients and 771 (922 hips) out of 1281 (1447 hips) female patients had radiographic features consistent with FAI. Ninety-four male hips (20.9%) and 45 female hips (4.9%) had cam type, 20 male hips (4.5%) and 225 female hips (24.4%) had pincer type and 335 male hips (74.6%) and 652 female hips (70.7%) had mixed type. The overall prevalence of radiographic findings consistent with FAI in male and female patients with hip pain was 61.1% and 60.2%, respectively. Mixed type was the most prevalent. The most common radiographic finding for cam-type FAI was an alpha angle >55°, and the most common radiographic finding for pincer-type FAI was a crossover sign. Male patients were found to have a higher prevalence of cam-type deformities, whereas female patients were found to have a higher prevalence of pincer-type deformities.

Ossification of the acetabular rim: a highly prevalent finding in asymptomatic non-osteoarthritic hips of all ages

ObjectiveTo estimate the prevalence of acetabular rim ossifications in the adult population with asymptomatic, morphologically normal hips at CT and to determine whether the presence of these ossifications is associated with patient- or hip-related parameters.MethodsWe prospectively included all patients undergoing thoracoabdominal CT over a 3-month period. After exclusion of patients with a clinical history of hip pathology and/or with signs of osteoarthritis on CT, we included a total of 150 hips from 75 patients. We analyzed the presence and the size of ossifications around the acetabular rim. The relationships between the size of acetabular rim ossifications and patient-related (sex, age, BMI) or hip-related parameters (joint space width, and cam- and pincer-type femoroacetabular impingement morphology) were tested using multiple regression analysis.ResultsThe prevalence of acetabular rim ossifications in this population of asymptomatic, non-osteoarthritic hips was 96% (95% CI = [80.1; 100.0]). The presence of ossifications and their size were correlated between the right and left hips (Spearman coefficient = 0.64 (95% CI = [0.46;0.79]), p < 0.05)). The size of acetabular rim ossifications was significantly associated with age (p < 0.0001) but not with BMI (p = 0.35), gender (p = 0.05), joint space width (p ≥ 0.53 for all locations), or any of the qualitative or quantitative parameters associated with femoroacetabular morphology (p ≥ 0.34).ConclusionAcetabular rim ossifications are highly prevalent in asymptomatic, non-osteoarthritic adult hips at all ages. Their size is not correlated with any patient- or hip-related parameters except for age. These findings suggest that ossifications at the acetabular rim, when present in isolation, should not be considered a sign of osteoarthritis or femoroacetabular impingement morphology.Key Points• Acetabular rim ossifications are extremely common in asymptomatic, non-osteoarthritic adult hips.• Acetabular rim ossifications are present independently from other signs of osteoarthritis in adult hips at all ages and should not be interpreted as a pathological finding.• The diagnosis of osteoarthritis or femoroacetabular impingement morphology should not be made based on the sole presence of ossifications at the acetabular rim.

Biochemical MRI With dGEMRIC Corresponds to 3D-CT Based Impingement Location for Detection of Acetabular Cartilage Damage in FAI Patients.

Background:Anterior femoroacetabular impingement (FAI) is associated with labral tears and acetabular cartilage damage in athletic and young patients. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) is an imaging method for detecting early damage to cartilage.Purpose:We evaluated the following questions: (1) What is the sensitivity and specificity of morphological magnetic resonance imaging (MRI) and dGEMRIC for detecting cartilage damage? Do the mean acetabular and femoral dGEMRIC indices differ between (2) superior acetabular clock positions with and without impingement and (3) between cam- and pincer-type FAI?Study Design:Cohort study (diagnosis); Level of evidence, 2.Methods:This was a retrospective comparative study of 21 hips (20 patients with symptomatic anterior FAI) without osteoarthritis on anteroposterior radiographs. Morphological MRI and dGEMRIC (3.0-T, 3-dimensional [3D] T1 maps, dual–flip angle technique) of the same hip joint were compared. Intraoperative acetabular cartilage damage was assessed in patients who underwent surgical treatment. Computed tomography (CT)–based 3D bone models of the same hip joint were used as the gold standard for the detection of impingement, and dGEMRIC indices and zones of morphologic damage were compared with the CT-based impingement zones.Results:Of the 21 hips, 10 had cam-type FAI and 8 had pincer-type FAI according to radiographs. The mean age was 30 ± 9 years (range, 17-48 years), 71% were female, and surgical treatment was performed in 52%. We found a significantly higher sensitivity (69%) for dGEMRIC compared with morphological MRI (42%) in the detection of cartilage damage (P < .001). The specificity of dGEMRIC was 83% and accuracy was 78%. The mean peripheral acetabular and femoral dGEMRIC indices for clock positions with impingement (485 ± 141 and 440 ± 121 ms) were significantly lower compared with clock positions without impingement (596 ± 183 and 534 ± 129 ms) (P < .001). Hips with cam-type FAI had significantly lower acetabular dGEMRIC indices compared with hips with pincer-type FAI on the anterosuperior clock positions (1 to 3 o’clock) (P = .018).Conclusion:MRI with dGEMRIC was more sensitive than morphological MRI, and lower dGEMRIC values were found for clock positions with impingement as detected on 3D-CT. This could aid in patient-specific diagnosis of FAI, preoperative patient selection, and surgical decision making to identify patients with cartilage damage who are at risk for inferior outcomes after hip arthroscopy.

Incidence of radiographic findings of femoroacetabular impingement in a healthy Egyptian population: a cross-sectional study

Background: Femoroacetabular impingement (FAI) is a unique pathological problem affecting young adults. It can be defined as the impingement between the proximal femur and the acetabular rim. Although clinical presentation usually is hip pain, it can be asymptomatic. Radiographic FAI findings are quite common in a population of healthy young adults and must be correlated to the clinical presentation. The aim of our study was to evaluate the incidence of radiographic findings of FAI among a cohort of healthy Egyptian participants. Methods: From March 2017 to April 2019, a cross-sectional study was conducted among a cohort of 160 Egyptians (100 men and 60 women) from 20 to 40 yr old. Anteroposterior and frog-leg lateral views were obtained for 320 hips. By using computer software (ICONICO Screen Protractor, ICONICO, Inc., New York, NY), we measured central edge crossover sign alpha angle and the acetabular index. Results: Pincer type FAI was found in 86 hips on the right side (53.27%) and in 104 hips on the left side (65%). Cam type of FAI was found in 54 hips on the right side (34.2%) and in 54 hips on the left side (34.2%). Mixed type was found in 26 hips on the right side (16.25%) and in 32 hips on the left side (20%). Conclusions: Radiographic FAI findings are quite common in Egyptian healthy young adults who have no hip symptoms. Clinical diagnosis is necessary for FAI and must be correlated with the radiographic data. Level of Evidence: Level II.