Labral tears are commonly associated with femoroacetabular impingement. We reviewed 151 patients (156 hips) with femoroacetabular impingement and labral tears who had been treated arthroscopically. These were subdivided into those who had undergone a labral repair (group 1) and those who had undergone resection of the labrum (group 2). In order to ensure the groups were suitably matched for comparison of treatment effects, patients with advanced degenerative changes (Tönnis grade > 2, lateral sourcil height < 2 mm and Outerbridge grade 4 changes in the weight-bearing area of the femoral head) were excluded, leaving 96 patients (101 hips) in the study. At a mean follow-up of 2.44 years (2 to 4), the mean modified Harris hip score in the labral repair group (group 1, 69 hips) improved from 60.2 (24 to 85) pre-operatively to 93.6 (55 to 100), and in the labral resection group (group 2, 32 hips) from 62.8 (29 to 96) pre-operatively to 88.8 (35 to 100). The mean modified Harris hip score in the labral repair group was 7.3 points greater than in the resection group (p = 0.036, 95% confidence interval 0.51 to 14.09). Labral detachments were found more frequently in the labral repair group and labral flap tears in the resection group. No patient in our study group required a subsequent hip replacement during the period of follow-up. This study shows that patients without advanced degenerative changes in the hip can achieve significant improvement in their symptoms after arthroscopic treatment of femoroacetabular impingement. Where appropriate, labral repair provides a superior result to labral resection

Aims. Acetabular retroversion is a recognized cause of hip impingement and can be influenced by pelvic tilt (PT), which changes in different functional positions. Positional changes in PT have not previously been studied in patients with acetabular retroversion. Methods. Supine and standing anteroposterior (AP) pelvic radiographs were retrospectively analyzed in 69 patients treated for symptomatic acetabular retroversion. Measurements were made for acetabular index (AI), lateral centre-edge angle (LCEA), crossover index, ischial spine sign, and posterior wall sign. The change in the angle of PT was measured both by the sacro-femoral-pubic (SFP) angle and the pubic symphysis to sacroiliac (PS-SI) index. Results. In the supine position, the mean PT (by SFP) was 1.05° (SD 3.77°), which changed on standing to a PT of 8.64° (SD 5.34°). A significant increase in posterior PT from supine to standing of 7.59° (SD 4.5°; SFP angle) and 5.89° (SD 3.33°; PS-SI index) was calculated (p < 0.001). There was a good correlation in PT change between measurements using SFP angle and PS-SI index (0.901 in the preoperative group and 0.815 in the postoperative group). Signs of retroversion were significantly reduced in standing radiographs compared to supine: crossover index (0.16 (SD 0.16) vs 0.38 (SD 0.15); p < 0.001), crossover sign (19/28 hips vs 28/28 hips; p < 0.001), ischial spine sign (10/28 hips vs 26/28 hips; p < 0.001), and posterior wall sign (12/28 hips vs 24/28 hips; p < 0.001). Conclusion. Posterior PT increased from supine to standing in patients with symptomatic acetabular retroversion. The features of acetabular retroversion were less evident on standing radiographs. The low PT angle in the supine position is a factor in the increased appearance of acetabular retroversion. Patients presenting with symptoms of hip impingement should be assessed by supine and standing pelvic radiographs to highlight signs of acetabular retroversion, and to assist with optimizing acetabular correction at the time of surgery. Cite this article: Bone Joint J 2022;104-B(7):786–791

Femoroacetabular impingement is a cause of hip pain in adults and is potentially a precursor of osteoarthritis. Our aim in this study was to determine the prevalence of bilateral deformity in patients with symptomatic cam-type femoroacetabular impingement as well as the presence of associated acetabular abnormalities and hip pain. We included all patients aged 55 years or less seen by the senior author for hip pain, with at least one anteroposterior and lateral pelvic radiograph available. All patients with dysplasia and/or arthritis were excluded. A total of 113 patients with a symptomatic cam-impingement deformity of at least one hip was evaluated. There were 82 men and 31 women with a mean age of 37.9 years (16 to 55). Bilateral cam-type deformity was present in 88 patients (77.8%) while only 23 of those (26.1%) had bilateral hip pain. Painful hips had a statistically significant higher mean alpha angle than asymptomatic hips (69.9° vs 63.1°, p < 0.001). Hips with an alpha angle of more than 60° had an odds ratio of being painful of 2.59 (95% confidence interval 1.32 to 5.08, p = 0.006) compared with those with an alpha angle of less than 60°. Of the 201 hips with a cam-impingement deformity 42% (84) also had a pincer deformity. Most patients with cam-type femoroacetabular impingement had bilateral deformities and there was an associated acetabular deformity in 84 of 201 patients (42%). This information is important in order to define the natural history of these deformities, and to determine treatment

Aims. The purpose of this study was to evaluate spinopelvic mechanics from standing and sitting positions in subjects with and without femoroacetabular impingement (FAI). We hypothesize that FAI patients will experience less flexion at the lumbar spine and more flexion at the hip whilst changing from standing to sitting positions than subjects without FAI. This increase in hip flexion may contribute to symptomatology in FAI. Patients and Methods. Male subjects were prospectively enrolled to the study (n = 20). Mean age was 31 years old (22 to 41). All underwent clinical examination, plain radiographs, and dynamic imaging using EOS. Subjects were categorized into three groups: non-FAI (no radiographic or clinical FAI or pain), asymptomatic FAI (radiographic and clinical FAI but no pain), and symptomatic FAI (patients with both pain and radiographic FAI). FAI was defined as internal rotation less than 15° and alpha angle greater than 60°. Subjects underwent standing and sitting radiographs in order to measure spine and femoroacetabular flexion. Results. Compared with non-FAI controls, symptomatic patients with FAI had less flexion at the spine (mean 22°, . sd. 12°, vs mean 35°, . sd. 8°; p = 0.04) and more at the hip (mean 72°, . sd. 6°, vs mean 62°, . sd. 8°; p = 0.047). Subjects with asymptomatic FAI had more spine flexion and similar hip flexion when compared to symptomatic FAI patients. Both FAI groups also sat with more anterior pelvic tilt than control patients. There were no differences in standing alignment among groups. Conclusion. Symptomatic patients with FAI require more flexion at the hip to achieve sitting position due to their inability to compensate through the lumbar spine. With limited spine flexion, FAI patients sit with more anterior pelvic tilt, which may lead to impingement between the acetabulum and proximal femur. Differences in spinopelvic mechanics between FAI and non-FAI patients may contribute to the progression of FAI symptoms. Cite this article: Bone Joint J 2018;100-B:1275–9

Femoroacetabular impingement (FAI) is commonly associated with early hip arthritis. We reviewed our series of 1300 hip resurfacing procedures. More than 90% of our male patients, with an average age of 53 years, had cam impingement lesions. In this condition, there are anterior femoral neck osteophytes, and a retroverted femoral head on a normally anteverted neck. It is postulated that FAI results in collision of the anterior neck of the femur against the rim of the acetabulum, causing damage to the acetabular labrum and articular cartilage, resulting in osteoarthritis. Early treatment of FAI involves arthroscopic or open removal of bone from the anterior femoral neck, as well as repair or removal of labral tears. However, once osteoarthritis has developed, hip replacement or hip resurfacing is indicated. Hip resurfacing can re-orient the head and re-shape the neck. This helps to restore normal biomechanics to the hip, eliminate FAI, and improve range of motion. Since many younger men with hip arthritis have FAI, and are also considered the best candidates for hip resurfacing, it is evident that resurfacing has a role in these patients

The February 2024 Children’s orthopaedics Roundup. 360. looks at: Hip impingement after in situ pinning causes decreased flexion and forced external rotation in flexion on 3D-CT; Triplane ankle fracture patterns in paediatric patients; Improved forearm rotation even after early conversion to below-elbow; Selective dorsal rhizotomy and cerebral palsy (CP) hip displacement; Abduction bracing following anterior open reduction for developmental dysplasia of the hip does not improve residual dysplasia or reduce secondary surgery; 40% risk of later total hip arthroplasty for in situ slipped capital femoral epiphysis (SCFE) pinning; Does brace treatment following closed reduction of developmental dysplasia of the hip improve acetabular coverage?; Waterproof hip spica casts for paediatric femur fractures

Femoroacetabular impingement (FAI) causes pain and chondrolabral damage via mechanical overload during movement of the hip. It is caused by many different types of pathoanatomy, including the cam ‘bump’, decreased head–neck offset, acetabular retroversion, global acetabular overcoverage, prominent anterior–inferior iliac spine, slipped capital femoral epiphysis, and the sequelae of childhood Perthes’ disease. Both evolutionary and developmental factors may cause FAI. Prevalence studies show that anatomic variations that cause FAI are common in the asymptomatic population. Young athletes may be predisposed to FAI because of the stress on the physis during development. Other factors, including the soft tissues, may also influence symptoms and chondrolabral damage. FAI and the resultant chondrolabral pathology are often treated arthroscopically. Although the results are favourable, morphologies can be complex, patient expectations are high and the surgery is challenging. The long-term outcomes of hip arthroscopy are still forthcoming and it is unknown if treatment of FAI will prevent arthrosis

There have been considerable recent advances in the understanding and management of femoroacetabular impingement and associated labral and chondral pathology. We have developed a classification system for acetabular chondral lesions. In our system, we use the six acetabular zones previously described by Ilizaliturri et al. The cartilage is then graded on a scale of 0 to 4 as follows: grade 0, normal articular cartilage lesions; grade 1, softening or wave sign; grade 2, cleavage lesion; grade 3, delamination; and grade 4, exposed bone. The site of the lesion is further classed as A, B or C based on whether the lesion is less than one-third of the distance from the acetabular rim to the cotyloid fossa, one-third to two-thirds of the same distance and greater than two-thirds of the distance, respectively. In order to validate the classification system, six surgeons graded ten video recordings of hip arthroscopy. Our findings showed a high intra-observer reliability of the classification system with an intraclass correlation coefficient of 0.81 and a high interobserver reliability with an intraclass correlation coefficient of 0.88. We have developed a simple reproducible classification system for lesions of the acetabular cartilage, which it is hoped will allow standardised documentation to be made of damage to the articular cartilage, particularly that associated with femoroacetabular impingement

Although the association between femoroacetabular impingement and osteoarthritis is established, it is not yet clear which hips have the greatest likelihood to progress rapidly to end-stage disease. We investigated the effect of several radiological parameters, each indicative of a structural aspect of the hip joint, on the progression of osteoarthritis. Pairs of plain anteroposterior pelvic radiographs, taken at least ten years apart, of 43 patients (43 hips) with a pistol-grip deformity of the femur and mild (Tönnis grade 1) or moderate (Tönnis grade 2) osteoarthritis were reviewed. Of the 43 hips, 28 showed evidence of progression of osteoarthritis. There was no significant difference in the prevalence of progression between hips with initial Tönnis grade 1 or grade 2 osteoarthritis (p = 0.31). Comparison of the hips with and without progression of arthritis revealed a significant difference in the mean medial proximal femoral angle (81° vs 87°, p = 0.004) and the presence of the posterior wall sign (39% vs 7%, p = 0.02) only. A logistic regression model was constructed to predict the influence of these two variables in the development of osteoarthritis. Mild to moderate osteoarthritis in hips with a pistol-grip deformity will not progress rapidly in all patients. In one-third, progression will take more than ten years to manifest, if ever. The individual geometry of the proximal femur and acetabulum partly influences this phenomenon. A hip with cam impingement is not always destined for end-stage arthritic degeneration

Slipped upper femoral epiphysis (SUFE) is one of the known causes of cam-type femoroacetabular impingement (FAI). The aim of this study was to determine the proportion of FAI cases considered to be secondary to SUFE-like deformities. . We performed a case–control study on 96 hips (75 patients: mean age 38 years (15.4 to 63.5)) that had been surgically treated for FAI between July 2005 and May 2011. Three independent observers measured the lateral view head–neck index (LVHNI) to detect any SUFE-like deformity on lateral hip radiographs taken in 45° flexion, 45° abduction and 30° external rotation. A control group of 108 healthy hips in 54 patients was included for comparison (mean age 36.5 years (24.3 to 53.9). The impingement group had a mean LVHNI of 7.6% (16.7% to -2%) versus 3.2% in the control group (10.8% to -3%) (p < 0.001). A total of 42 hips (43.7%) had an index value > 9% in the impingement group versus only six hips (5.5%) in the control group (p < 0.001). The impingement group had a mean α angle of 73.9° (96.2° to 53.4°) versus 48.2° (65° to 37°) in the control group (p < 0.001). Our results suggest that SUFE is one of the primary aetiological factors for cam-type FAI. Cite this article: Bone Joint J 2014; 96-B:724–9

Aims. Abnormal femoral torsion (FT) is increasingly recognized as an additional cause for femoroacetabular impingement (FAI). It is unknown if in-toeing of the foot is a specific diagnostic sign for increased FT in patients with symptomatic FAI. The aims of this study were to determine: 1) the prevalence and diagnostic accuracy of in-toeing to detect increased FT; 2) if foot progression angle (FPA) and tibial torsion (TT) are different among patients with abnormal FT; and 3) if FPA correlates with FT. Patients and Methods. A retrospective, institutional review board (IRB)-approved, controlled study of 85 symptomatic patients (148 hips) with FAI or hip dysplasia was performed in the gait laboratory. All patients had a measurement of FT (pelvic CT scan), TT (CT scan), and FPA (optical motion capture system). We allocated all patients to three groups with decreased FT (< 10°, 37 hips), increased FT (> 25°, 61 hips), and normal FT (10° to 25°, 50 hips). Cluster analysis was performed. Results. We found a specificity of 99%, positive predictive value (PPV) of 93%, and sensitivity of 23% for in-toeing (FPA < 0°) to detect increased FT > 25°. Most of the hips with normal or decreased FT had no in-toeing (false-positive rate of 1%). Patients with increased FT had significantly (p < 0.001) more in-toeing than patients with decreased FT. The majority of the patients (77%) with increased FT walk with a normal foot position. The correlation between FPA and FT was significant (r = 0.404, p < 0.001). Five cluster groups were identified. Conclusion. In-toeing has a high specificity and high PPV to detect increased FT, but increased FT can be missed because of the low sensitivity and high false-negative rate. These results can be used for diagnosis of abnormal FT in patients with FAI or hip dysplasia undergoing hip arthroscopy or femoral derotation osteotomy. However, most of the patients with increased FT walk with a normal foot position. This can lead to underestimation or misdiagnosis of abnormal FT. We recommend measuring FT with CT/MRI scans in all patients with FAI. Cite this article: Bone Joint J 2019;101-B:1218–1229

We retrospectively examined the long-term outcome of 96 asymptomatic hips in 96 patients with a mean age of 49.3 years (16 to 65) who had radiological evidence of femoroacetabular impingement. When surveillance commenced there were 17, 34, and 45 hips with cam, pincer, and mixed impingement, respectively. Overall, 79 hips (82.3%) remained free of osteoarthritis for a mean of 18.5 years (10 to 40). In contrast, 17 hips (17.7%) developed osteoarthritis at a mean of 12 years (2 to 28). No statistically significant difference was found in the rates of development of osteoarthritis among the three groups (p = 0.43). Regression analysis showed that only the presence of idiopathic osteoarthritis of the contralateral diseased hip was predictive of development of osteoarthritis on the asymptomatic side (p = 0.039). We conclude that a substantial proportion of hips with femoroacetabular impingement may not develop osteoarthritis in the long-term. Accordingly, in the absence of symptoms, prophylactic surgical treatment is not warranted

We reviewed the clinical outcome of arthroscopic femoral osteochondroplasty for cam femoroacetabular impingement performed between August 2005 and March 2009 in a series of 40 patients over 60 years of age. The group comprised 26 men and 14 women with a mean age of 65 years (60 to 82). The mean follow-up was 30 months (12 to 54). The mean modified Harris hip score improved by 19.2 points (95% confidence interval 13.6 to 24.9; p < 0.001) while the mean non-arthritic hip score improved by 15.0 points (95% confidence interval 10.9 to 19.1, p < 0.001). Seven patients underwent total hip replacement after a mean interval of 12 months (6 to 24 months) at a mean age of 63 years (60 to 70). The overall level of satisfaction was high with most patients indicating that they would undergo similar surgery in the future to the contralateral hip, if indicated. No serious complications occurred. Arthroscopic femoral osteochondroplasty performed in selected patients over 60 years of age, who have hip pain and mechanical symptoms resulting from cam femoroacetabular impingement, is beneficial with a minimal risk of complications at a mean follow-up of 30 months

Over an eight-month period we prospectively enrolled 122 patients who underwent arthroscopic surgery of the hip for femoroacetabular impingement and met the inclusion criteria for this study. Patients with bilateral hip arthroscopy, avascular necrosis and previous hip surgery were excluded. Ten patients refused to participate leaving 112 in the study. There were 62 women and 50 men. The mean age of the patients was 40.6 yrs (95% confidence interval (CI) 37.7 to 43.5). At arthroscopy, 23 patients underwent osteoplasty only for cam impingement, three underwent rim trimming only for pincer impingement, and 86 underwent both procedures for mixed-type impingement. The mean follow-up was 2.3 years (2.0 to 2.9). The mean modified Harris hip score (HHS) improved from 58 to 84 (mean difference = 24 (95% CI 19 to 28)) and the median patient satisfaction was 9 (1 to 10). Ten patients underwent total hip replacement at a mean of 16 months (8 to 26) after arthroscopy. The predictors of a better outcome were the pre-operative modified HHS (p = 0.018), joint space narrowing ≥ 2 mm (p = 0.005), and repair of labral pathology instead of debridement (p = 0.032). Hip arthroscopy for femoroacetabular impingement, accompanied by suitable rehabilitation, gives a good short-term outcome and high patient satisfaction

The radiological evaluation of the anterolateral femoral head is an essential tool for the assessment of the cam type of femoroacetabular impingement. CT, MRI and frog lateral plain radiographs have all been suggested as imaging options for this type of lesion. The alpha angle is accepted as a reliable indicator of the cam type of impingement and may also be used as an assessment for the successful operative correction of the cam lesion. We studied the alpha angles of 32 consecutive patients with femoroacetabular impingement. The angle measured on frog lateral radiographs using templating tools was compared with that measured on CT scans in order to assess the reliability of the frog lateral view in analysing the alpha angle in cam impingement. A high interobserver reliability was noted for the assessment of the alpha angle on the frog lateral view with an intraclass correlation coefficient of 0.83. The mean alpha angle measured on the frog lateral view was 58.71° (32° to 83.3°) and that by CT was 65.11° (30° to 102°). A poor intraclass correlation coefficient (0.08) was noted between the measurements using the two systems. The frog lateral plain radiograph is not reliable for measuring the alpha angle. Various factors may be responsible for this such as the projection of the radiograph, the positioning of the patient and the quality of the image. CT may be necessary for accurate measurement of the alpha angle

Deformity after slipped upper femoral epiphysis (SUFE) can cause cam-type femoroacetabular impingement (FAI) and subsequent osteoarthritis (OA). However, there is little information regarding the radiological assessment and clinical consequences at long-term follow-up. We reviewed 36 patients (43 hips) previously treated by in situ fixation for SUFE with a mean follow-up of 37 years (21 to 50). Three observers measured the femoral head ratio (FHR), lateral femoral head ratio (LFHR), α-angle on anteroposterior (AP) and frog-leg lateral views, and anterior femoral head–neck offset ratio (OSR). A Harris hip score < 85 and/or radiologically diagnosed osteoarthritis (OA) was classified as a poor outcome. Patients with SUFE had significantly higher FHR, LFHR and α-angles and lower OSR than a control group of 22 subjects (35 hips) with radiologically normal hips. The interobserver agreement was less, with wider limits of agreement (LOA), in hips with previous SUFE than the control group. At long-term follow-up abnormal α-angles correlated with poor outcome, whereas FHR, LFHR and OSR did not. We conclude that persistent deformity with radiological cam FAI after SUFE is associated with poorer clinical and radiological long-term outcome. Although the radiological measurements had quite wide limits of agreement, they are useful for the diagnosis of post-slip deformities in clinical practice

Young adults with hip pain secondary to femoroacetabular impingement (FAI) are rapidly being recognised as an important cohort of orthopaedic patients. Interest in FAI has intensified over the last decade since its recognition as a precursor to arthritis of the hip and the number of publications related to the topic has increased exponentially in the last decade. Although not all patients with abnormal hip morphology develop osteoarthritis (OA), those with FAI-related joint damage rapidly develop premature OA. There are no explicit diagnostic criteria or definitive indications for surgical intervention in FAI. Surgery for symptomatic FAI appears to be most effective in younger individuals who have not yet developed irreversible OA. The difficulty in predicting prognosis in FAI means that avoiding unnecessary surgery in asymptomatic individuals, while undertaking intervention in those that are likely to develop premature OA poses a considerable dilemma. FAI treatment in the past has focused on open procedures that carry a potential risk of complications.

Recent developments in hip arthroscopy have facilitated a minimally invasive approach to the management of FAI with few complications in expert hands. Acetabular labral preservation and repair appears to provide superior results when compared with debridement alone. Arthroscopic correction of structural abnormalities is increasingly becoming the standard treatment for FAI, however there is a paucity of high-level evidence comparing open and arthroscopic techniques in patients with similar FAI morphology and degree of associated articular cartilage damage. Further research is needed to develop an understanding of the natural course of FAI, the definitive indications for surgery and the long-term outcomes.

Cite this article: Bone Joint J 2013;95-B, Supple A:26–30.

We examined the morphology of mammalian hips asking whether evolution can explain the morphology of impingement in human hips. We describe two stereotypical mammalian hips, coxa recta and coxa rotunda. Coxa recta is characterised by a straight or aspherical section on the femoral head or head-neck junction. It is a sturdy hip seen mostly in runners and jumpers. Coxa rotunda has a round femoral head with ample head-neck offset, and is seen mostly in climbers and swimmers.

Hominid evolution offers an explanation for the variants in hip morphology associated with impingement. The evolutionary conflict between upright gait and the birth of a large-brained fetus is expressed in the female pelvis and hip, and can explain pincer impingement in a coxa profunda. In the male hip, evolution can explain cam impingement in coxa recta as an adaptation for running.