Cam impingement of the hip—a risk factor for hip osteoarthritis

Development of a novel rabbit model for femoroacetabular impingement through surgically induced acetabular overcoverage

There is a lack of validated small animal models for femoroacetabular impingement (FAI) that induce intra-articular lesions and cause osteoarthritis (OA) progression. The gene expression profile of articular cartilage in patients with FAI has not been characterized in animal studies. The purpose of this study is to describe a novel rabbit model for FAI with validated induction of intra-articular lesions and OA progression and to characterize the gene expression pattern in impinged cartilage using this model. Thirty 6-month-old New Zealand White rabbits underwent unilateral endobutton implant placement at the acetabular rim to surgically create overcoverage. Radiological assessment confirmed secure placement of endobutton at the acetabular rim for all operated hips with a mean alteration in lateral center-edge angle (ΔLCEA) of 16.2 ± 6.6°. Gross inspection revealed secondary cartilage injuries in the anterosuperior region of the femoral head for the operated hips. Cartilage injuries were shown to exacerbate with increased impingement duration, as demonstrated by the modified Outerbridge scores and Mankin scores. Immunostaining and quantitative real-time polymerase chain reaction revealed elevated expression of inflammatory, anabolic and catabolic genes in impinged cartilage. RNA sequencing analysis of cartilage tissue revealed a distinct transcriptome profile and identified C-KIT, CD86, and CD68 as central markers. Our study confirmed that the novel rabbit FAI model created acetabular overcoverage and produced articular cartilage injury at the impingement zone. Cartilage from the impingement zone demonstrated a heightened metabolic state, corroborating with the gene expression pattern observed in patients with FAI.

Relationship Between Hip and Groin Pain and Hip Range of Motion in Amateur Soccer and Australian Rules Football Players

Background

The relationship between hip/groin pain and hip range of motion (ROM) is unclear.

Purpose

To explore the relationship between hip/groin pain and hip joint ROM and examine the influence of sex and cam morphology on this relationship.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Included were 184 amateur soccer and Australian Rules football players (276 hips; 20% women; median age, 26 years; interquartile range, 24-30 years) with hip/groin pain >6 months and a positive flexion-adduction-internal-rotation (FADIR) test, and 50 matched asymptomatic control players (98 hips; 28% women, median age, 26 years; interquartile range, 23-31 years). Hip ROM measures were flexion, internal and external rotation at 90° of hip flexion, total rotation (internal and external), and bent-knee fall out (BKFO). Cam morphology was determined from anteroposterior pelvis or 45° Dunn radiographs, defined by an alpha angle ≥60°. Linear regression models with generalized estimating equations were used to examine the relationship between group (symptomatic and asymptomatic) and each ROM measure. Interaction terms (group × cam morphology or group × sex) were included to examine if relationships between group and hip ROM were influenced by cam morphology or sex. Where appropriate, models were adjusted for sex, age, and cam morphology.

Results

An interaction between the relationship between group × cam and internal rotation ROM was found. Symptomatic players with cam morphology had lower internal rotation ROM than controls with cam morphology (adjusted mean difference [AMD] = -4.5°; 95% CI, -7.4° to -1.6°). Hip/groin pain was not associated with internal rotation ROM if cam morphology was absent. A significant interaction was also found for group × sex and BKFO and total rotation ROM. Symptomatic women had lower total rotation ROM than control women (AMD = -8.2°; 95% CI, -14.1° to -2.2°), but no difference was seen in men. BKFO range was lower in men with hip/groin pain compared with control men (AMD = 1.6 cm; 95% CI, 0.3-3.0 cm), but no difference was seen in women. Flexion and external rotation ROM did not differ between symptomatic and control hips.

Conclusion

Cam morphology was an effect modifier of the relationship between hip/groin pain and internal rotation ROM. Sex-related differences were also observed in the relationship between hip/groin pain and hip ROM.

Femoroacetabular impingement syndrome in middle-aged individuals is strongly associated with the development of hip osteoarthritis within 10-year follow-up: a prospective cohort study (CHECK)

OBJECTIVE

The objective is to determine the association and absolute risk of femoroacetabular impingement syndrome (FAIS) for the development of radiographic hip osteoarthritis (RHOA).

METHODS

This is a nationwide, multicentre prospective cohort study (Cohort Hip and Cohort Knee) with 1002 individuals aged between 45 and 65 years. Hips without definitive RHOA (Kellgren-Lawrence (KL) grade≤1) at baseline and with anteroposterior pelvic radiographs at baseline and 10-year follow-up available (n=1386 hips) were included. FAIS was defined by the baseline presence of a painful hip, limited internal hip rotation≤25° and cam morphology defined by an alpha angle>60°. The outcomes were incident RHOA (KL grade≥2 or total hip replacement (THR)) and incident end-stage RHOA (KL≥3 or THR) within 10 years.

RESULTS

Of the 1386 included hips (80% women; mean age 55.7±5.2 years), 21 hips fulfilled criteria for FAIS and 563 hips did not fulfil any of the FAIS criteria (reference group; no symptoms, no signs, no cam morphology). Within 10-year follow-up, 221 hips (38%) developed incident RHOA and 15 hips (3%) developed end-stage RHOA (including 9 hips with THR). Adjusted for sex, age and body mass index, FAIS with cam morphology resulted in an OR of 6.85 (95% CI 2.10 to 22.35) for incident RHOA and 47.82 (95% CI 12.51 to 182.76) for incident end-stage RHOA, compared with hips not having any FAIS criteria. The absolute risk of FAIS was 81% for incident RHOA and 33% for incident end-stage RHOA.

CONCLUSION

FAIS was strongly associated with the development of RHOA within 10 years. Although the baseline prevalence of FAIS was low, the high absolute risk of FAIS for RHOA warrants further studies to determine preventive strategies.

The different subtypes of cam morphology as defined by statistical shape modeling and their relationship with the development of hip osteoarthritis: A nationwide prospective cohort study (CHECK) with 10 years follow-up

OBJECTIVE

To determine if subtypes of cam morphology on anteroposterior radiographs exist using statistical shape modeling (SSM), and to assess their association with incident radiographic hip osteoarthritis (RHOA) within 10 years.

DESIGN

The nationwide prospective Cohort Hip and Cohort Knee (CHECK) study included 1002 participants aged 45-65 years with 10-year follow-up. Subtypes of cam morphology were defined as SSM-based shape variations of femoral head-neck junction that are associated with baseline cam morphology (alpha angle ≥60°). The association between each subtype in hips free of osteoarthritis at baseline (Kellgren & Lawrence (KL) grade <2) and incident RHOA (KL grade≥2, or a total hip replacement) was estimated using logistic regression at 10-year follow-up and stratified by sex.

RESULTS

In sex-combined group, but also for males and females separately, cam morphology subtypes were captured in modes 1, 3, 4, and 5 with odds ratios (ORs) ranging from 0.39 (0.27-0.58) to 2.25 (1.64-3.10). For sex-combined group, only mode 3, a flattened head-neck junction, was associated with incident RHOA (OR:1.14, 1.02-1.27). Males' modes 1 and 3 and females' modes 3 and 4 were associated with RHOA. Notably, the female mode 4, a slightly flattened neck but with subtle curvature, was significantly protective for RHOA (OR:0.88, 0.80-0.98).

CONCLUSIONS

We identified four distinct morphological subtypes of cam morphology defined by alpha angle. Only some subtypes were found acting as risk factors for RHOA at 10-year follow-up, which differed between males and females. This highlights the need to study cam morphology beyond the alpha angle alone.

Radiological predictors of outcomes in hip arthroscopy for femoroacetabular impingement

Aims

Hip arthroscopy has gained prominence as a primary surgical intervention for symptomatic femoroacetabular impingement (FAI). This study aimed to identify radiological features, and their combinations, that predict the outcome of hip arthroscopy for FAI.

Methods

A prognostic cross-sectional cohort study was conducted involving patients from a single centre who underwent hip arthroscopy between January 2013 and April 2021. Radiological metrics measured on conventional radiographs and magnetic resonance arthrography were systematically assessed. The study analyzed the relationship between these metrics and complication rates, revision rates, and patient-reported outcomes.

Results

Out of 810 identified hip arthroscopies, 359 hips were included in the study. Radiological risk factors associated with unsatisfactory outcomes after cam resection included a dysplastic posterior wall, Tönnis grade 2 or higher, and over-correction of the α angle. The presence of acetabular retroversion and dysplasia were also significant predictors for worse surgical outcomes. Notably, over-correction of both cam and pincer deformities resulted in poorer outcomes than under-correction.

Conclusion

We recommend caution in performing hip arthroscopy in patients who have three positive acetabular retroversion signs. Acetabular dysplasia with a lateral centre-edge angle of less than 20° should not be treated with isolated hip arthroscopy. Acetabular rim-trimming should be avoided in patients with borderline dysplasia, and care should be taken to avoid over-correction of a cam deformity and/or pincer deformity.

Effects of physical exercise on muscle function of the knee, pain and quality of life in postmenopausal women with knee osteoarthritis: A systematic review with meta-analysis

Objective of this study was to investigate the effects of physical exercise on muscle function of the knee, pain and quality of life in postmenopausal women with knee osteoarthritis (OA). An electronic search was conducted of the PubMed, Embase, Web of Science, Cochrane Library, LILACS and PEDro databases for relevant articles published up to September 2023. Only randomized clinical trials with interventions involving physical exercise of any modality in postmenopausal women with knee OA were included. This review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses and the Cochrane Recommendations. Methodological quality of the studies selected was assessed using the PEDro scale and the evidence was synthesized using the Grading of Recommendations, Assessment, Development and Evaluation scale. Among the 169 articles identified, five were included in the present systematic review and enabled meta-analysis of the outcomes physical function, pain and stiffness. The findings demonstrated the effectiveness of physical exercise in improving physical function, assessed through the Six-Minute Walk Test and the WOMAC scale's physical function domain, compared to the control group. However, no significant differences were observed in pain or stiffness outcomes between the treatment and control groups. Unfortunately, insufficient data precluded a meta-analysis for knee muscle function and quality of life outcomes. Despite the potential of physical exercise to enhance physical function in postmenopausal women with knee OA, the study highlights a lack of standardization in assessment tools and tests, limiting the feasibility of meta-analysis. PROSPERO REGISTRATION: CRD42022316476.

Pincer Morphology Is Not Associated With Hip Osteoarthritis Unless Hip Pain Is Present: Follow-Up Data From a Prospective Cohort Study

OBJECTIVE

The objective of this study was to assess the relationship between pincer morphology and radiographic hip osteoarthritis (RHOA) over 2, 5, 8, and 10 years' follow-up and to study the interaction between pincer morphology and pain.

METHODS

Individuals from the prospective Cohort Hip and Cohort Knee study were drawn. Anteroposterior pelvic and false profile radiographs were obtained. Hips free of definite RHOA (Kellgren and Lawrence [KL] grade 0 or 1) at baseline were included. Pincer morphology was defined as a lateral or anterior center edge angle or both ≥40° at baseline. Incident RHOA was defined as KL ≥ 2 or total hip replacement at follow-up. Multivariable logistic regression with generalized estimating equations estimated the associations at follow-up. Associations were expressed as unadjusted odds ratios (ORs) and adjusted ORs with 95% confidence intervals (CIs). An interaction term was added to investigate whether pincer morphology had a different effect on symptomatic hips.

RESULTS

Incident RHOA developed in 69 hips (5%) at 2 years' follow-up, in 178 hips (14%) at 5 years' follow-up, in 279 hips (24%) at 8 years' follow-up, and in 495 hips (42%) at 10 years' follow-up. No significant associations were found between pincer morphology and incident RHOA (adjusted OR 0.35 [95% CI 0.06-2.15]; adjusted OR 1.50 [95% CI 0.94-2.38]). Significant interactions between pain and anterior pincer morphology in predicting incident RHOA were found at 5, 8, and 10 years' follow-up (OR 1.97 [95% CI 1.03-3.78]; OR 3.41 [95% CI 1.35-8.61]).

CONCLUSION

No associations were found between radiographic pincer morphology and incident RHOA at any follow-up moment. Anteriorly located pincer morphology with hip pain, however, was significantly associated with incident RHOA. This highlights the importance of studying symptoms and hip morphology simultaneously.

Increased Alpha Angles and Younger Age Increase the Risk of Contralateral Femoral Acetabular Impingement Syndrome Symptom Development and Surgical Intervention: A Systematic Review

PURPOSE

To identify the preoperative risk factors associated with contralateral symptom development and surgical intervention for patients presenting with unilateral femoral acetabular impingement (FAI) syndrome.

METHODS

A literature search was performed using PubMed and Scopus computerized databases according to the 2020 Preferred Reporting Items for Systematic Meta-Analyses guidelines. Studies evaluating preoperative risk factors associated with the contralateral progression of FAI were included. Quality assessment was completed using the Methodological Index for Non-Randomized Studies criteria.

RESULTS

A total of 5 studies (n = 1,011 patients; mean age, 29.9 years) published from 2013 to 2022 met the inclusion/exclusion criteria. Mean follow-up ranged from 12 to 132 months. The overall rate of contralateral progression of symptomatic FAI ranged from 32.4% to 81%. Increased alpha angle was frequently reported factor associated with contralateral symptom progression, followed by decreased total arc of rotation, decreased internal rotation, reduced neck-shaft angle, and head-neck offset. The incidence rate of progression to contralateral surgery ranged from 15.7% to 24% of patients. Younger age was frequently reported factor associated with contralateral surgical intervention, followed by male sex, increased level of activity, and increased alpha angle.

CONCLUSIONS

Increased alpha angle and younger age were commonly reported risk factors associated with an increased risk of symptom development and surgical progression of contralateral FAI, respectively. The overall rate of contralateral progression of symptomatic FAI and the rate of progression to surgical intervention ranged up to 81% and 24%, respectively. This information may help both patients and surgeons to establish expectations regarding development of contralateral hip symptoms and possible need for surgery.

LEVEL OF EVIDENCE

Level III; systematic review of Level II-III studies.

Hip Contact Forces During Sprinting in Femoroacetabular Impingement Syndrome

PURPOSE

Sprinting often provokes hip pain in individuals with femoroacetabular impingement syndrome (FAIS). Asphericity of the femoral head-neck junction (cam morphology) characteristic of FAIS can increase the risk of anterior-superior acetabular cartilage damage. This study aimed to 1) compare hip contact forces (magnitude and direction) during sprinting between individuals with FAIS, asymptomatic cam morphology (CAM), and controls without cam morphology, and 2) identify the phases of sprinting with high levels of anteriorly directed hip contact forces.

METHODS

Forty-six recreationally active individuals with comparable levels of physical activity were divided into three groups (FAIS, 14; CAM, 15; control, 17) based on their history of hip/groin pain, results of clinical impingement tests, and presence of cam morphology (alpha angle >55°). Three-dimensional marker trajectories, ground reaction forces, and electromyograms from 12 lower-limb muscles were recorded during 10-m overground sprinting trials. A linearly scaled electromyogram-informed neuromusculoskeletal model was used to calculate hip contact force magnitude (resultant, anterior-posterior, inferior-superior, medio-lateral) and angle (sagittal and frontal planes). Between-group comparisons were made using two-sample t -tests via statistical parametric mapping ( P < 0.05).

RESULTS

No significant differences in magnitude or direction of hip contact forces were observed between FAIS and CAM or between FAIS and control groups during any phase of the sprint cycle. The highest anteriorly directed hip contact forces were observed during the initial swing phase of the sprint cycle.

CONCLUSIONS

Hip contact forces during sprinting do not differentiate recreationally active individuals with FAIS from asymptomatic individuals with and without cam morphology. Hip loading during early swing, where peak anterior loading occurs, may be a potential mechanism for cartilage damage during sprinting-related sports in individuals with FAIS and/or asymptomatic cam morphology.

Physical Therapy May Not Be Successful for Patients With Cam-Type Femoroacetabular Impingement Syndrome and May Result in Insufficient Hip Range of Motion When Femoral Anteversion Is Less Than 16° and α-Angle Is Greater Than 65°

PURPOSE

To identify factors associated with insufficient range of motion (ROM) improvement after the posterior pelvic tilt change in cam-type femoroacetabular impingement syndrome.

METHODS

Preoperative computed tomography images from 71 consecutive patients with femoroacetabular impingement syndrome treated with arthroscopic cam resection were evaluated. Using a dynamic computer simulation program, 3-dimensional models with a 10° posterior pelvic tilt from the supine functional pelvic plane (baseline) were created by computed tomography models. Patients were divided into 2 groups: those who experienced >10° (effective group) and ≤10° (ineffective group) improvements in internal rotation at 90° flexion after a 10° posterior pelvic tilt. Demographic characteristics; preoperative range of internal rotation at 90° flexion; and radiographic parameters, including Tönnis grade, lateral center-edge angle, acetabular roof obliquity angle, central acetabular anteversion, cranial acetabular anteversion, femoral anteversion, and α angle, were compared in the 2 groups. Univariate and multivariable logistic regression analyses were performed to evaluate factors associated with insufficient ROM improvement following a 10° posterior pelvic tilt.

RESULTS

The 71 patients included 58 men and 13 women, of mean age 41.4 ± 14.6 years. Posterior pelvic tilt was effective in 13 hips and ineffective in 58. Univariate analysis showed that preoperative range of internal rotation at 90°flexion, femoral anteversion, and α angle differed significantly in the 2 groups. Multivariable analysis showed that femoral anteversion <16° (odds ratio 7.4; 95% confidence interval 1.6-35; P = .012) and α angle >65° (odds ratio 6.7; 95% confidence interval 1.2-37; P = .027) were significant factors associated with insufficient ROM improvement after posterior pelvic tilt.

CONCLUSIONS

Physical therapy may not be successful for patients with cam-type femoroacetabular impingement syndrome and may result in insufficient hip ROM when femoral anteversion is less than 16° and α-angle is greater than 65°.

CLINICAL RELEVANCE

Patients with a prominent cam-type deformity and lower anterior femoral anteversion are at high risk of clinical failure following improvement in pelvic mobility by conservative treatment alone and are likely to benefit from surgery for cam deformity.

Analysis of cam location characteristics in FAI syndrome patients from 3D MR images demonstrates sex-specific differences

Cam femoroacetabular impingement (FAI) syndrome is associated with hip osteoarthritis (OA) development. Hip shape features, derived from statistical shape modeling (SSM), are predictive for OA incidence, progression, and arthroplasty. Currently, no three-dimensional (3D) SSM studies have investigated whether there are cam shape differences between male and female patients, which may be of potential clinical relevance for FAI syndrome assessments. This study analyzed sex-specific cam location and shape in FAI syndrome patients from clinical magnetic resonance examinations (M:F 56:41, age: 16-63 years) using 3D focused shape modeling-based segmentation (CamMorph) and partial least squares regression to obtain shape features (latent variables [LVs]) of cam morphology. Two-way analysis of variance tests were used to assess cam LV data for sex and cam volume severity differences. There was no significant interaction between sex and cam volume severity for the LV data. A sex main effect was significant for LV 1 (cam size) and LV 2 (cam location) with medium to large effect sizes (p < 0.001, d > 0.75). Mean results revealed males presented with a superior-focused cam, whereas females presented with an anterior-focused cam. When stratified by cam volume, cam morphologies were located superiorly in male and anteriorly in female FAI syndrome patients with negligible, mild, or moderate cam volumes. Both male and female FAI syndrome patients with major cam volumes had a global cam distribution. In conclusion, sex-specific cam location differences are present in FAI syndrome patients with negligible, mild, and moderate cam volumes, whereas major cam volumes were globally distributed in both male and female patients.

Factors associated with cam deformity in Japanese local residents

Femoroacetabular impingement has increasingly been recognized as a cause of primary hip osteoarthritis; however, its epidemiological indications remain unclear. We aimed to clarify the epidemiological indications and factors associated with cam deformity in a large-scale population-based cohort in Japan. Overall, 1480 participants (2960 hips) (491 men, 989 women; mean age, 65.3 years) analyzed in the third survey of the Research on Osteoarthritis/Osteoporosis Against Disability study were included. The α angle and spinopelvic parameters (lumbar lordosis, sacral slope, pelvic tilt, and pelvic incidence) were radiographically measured. Cam deformity was defined as α angle ≥ 60°. Overall, the cam deformity prevalence was 147/2960 (5.0%). Cam deformity prevalence tended to increase with age; in the univariate analysis, a higher percentage of men was observed in the group with cam deformity than in the group without it. No relationship was observed between cam deformity and hip pain. Factors associated with α angle were examined via multiple regression analysis for each gender; α angle was significantly associated with age and BMI in each gender. The α angle and PT were correlated in women. Thus, α angle and cam deformity prevalence increase with age in Japanese individuals. Accordingly, cam deformity can be considered a developmental disease.

The association between lateral hip muscle size/intramuscular fat infiltration and hip strength in active young adults with long standing hip/groin pain

OBJECTIVES

To investigate associations between lateral hip muscle size/intramuscular fat infiltration (MFI) and hip strength in active young adults with longstanding hip/groin pain.

DESIGN

Cross-sectional study.

SETTING

University/Clinical.

PARTICIPANTS

Sub-elite soccer and Australian Football players (n = 180; 37 female) with long standing hip/groin pain.

MAIN OUTCOME MEASURES

Muscle size (volume) and MFI of gluteus maximus, medius, and minimis, and tensor fascia latae (TFL) were assessed using magnetic resonance imaging. Isometric hip strength was measured with handheld dynamometry. Associations between muscle size/MFI were assessed using linear regression models, adjusted for body mass index and age, with sex-specific interactions.

RESULTS

Positive associations were identified between lateral hip muscle volume and hip muscle strength, particularly for gluteus maximus and gluteus minimus volume. For all muscles, hip abduction was associated with an increase in strength by up to 0.69 N (R2 ranging from 0.29 to 0.39). These relationships were consistent across sexes with no sex interactions observed. No associations were found between MFI and strength measures.

CONCLUSION

Greater lateral hip muscle volumes are associated with greater hip strength in active young adults with long standing hip/groin pain, irrespective of sex. Gluteus maximus and minimus volume showed the most consistent relationships with hip strength across multiple directions.

Cam morphology is strongly and consistently associated with development of radiographic hip osteoarthritis throughout 4 follow-up visits within 10 years

OBJECTIVE

To determine the association between cam morphology and the development of radiographic hip osteoarthritis (RHOA) at four time points within 10-year follow-up.

DESIGN

The nationwide prospective Cohort Hip and Cohort Knee study includes 1002 participants aged 45-65 years with 2-, 5-, 8-, and 10-year follow-ups. The associations of cam morphology (alpha angle >60°) and large cam morphology (alpha angle >78°) in hips free of osteoarthritis at baseline (Kellgren & Lawrence (KL) grade <2) with the development of both incident RHOA (KL grade≥2) and end-stage RHOA (KL grade≥3) were estimated using logistic regression with generalized estimating equation at each follow-up and using Cox regression over 10 years, adjusted for age, sex, and body mass index.

RESULTS

Both cam morphology and large cam morphology were associated with the development of incident RHOA at all follow-ups with adjusted Odd Ratios (aORs) ranging from 2.7 (95% Confidence interval 1.8-4.1) to 2.9 (95% CI 2.0-4.4) for cam morphology and ranging from 2.5 (95% CI 1.5-4.3) to 4.2 (95% CI 2.2-8.3) for large cam morphology. For end-stage RHOA, cam morphology resulted in aORs ranging from 4.9 (95% CI 1.8-13.2) to 8.5 (95% CI 1.1-64.4), and aORs for large cam morphology ranged from 6.7 (95% CI 3.1-14.7) to 12.7 (95% CI 1.9-84.4).

CONCLUSIONS

Cam morphology poses the hip at 2-13 times increased odds for developing RHOA within a 10-year follow-up. The association was particularly strong for large cam morphology and end-stage RHOA, while the strength of association was consistent over time.

Non-operative Management and Outcomes of Femoroacetabular Impingement Syndrome

PURPOSE

To serve as a guide for non-operative physicians in the management of femoroacetabular impingement syndrome and provide an algorithm as to when to refer patients for potential surgical management.

RECENT FINDINGS

Supervised physical therapy programs that focus on active strengthening and core strengthening are more effective than unsupervised, passive, and non-core-focused programs. There is promising evidence for the use of intra-articular hyaluronic acid and PRP as adjunct treatment options. Recent systematic reviews and meta-analyses have found that in young active patients, hip arthroscopy demonstrates improved short-term outcomes over physical therapy. The decision for the management of FAIS is complex and should be specific to each patient. Consideration of the patient's age, timing to return to sport, longevity of treatment, hip morphology, and degree of cartilage degeneration is required to make an informed decision in the treatment of these patients.

Association of Chondrolabral Lesions with Ultrasound-Guided Detection of Pathological Head-Neck Contour

OBJECTIVE

This study aimed to investigate whether the asphericity of the neck-head junction of the femur confirmed via ultrasound is associated with further pathology due to femoro-acetabular impingement (FAI).

METHODOLOGY

After a clinical examination with positive FAI tests, an ultrasound examination of the hip was performed. In the case of asphericity, a quantitative ultrasound-assisted assessment of the hip was performed, followed by contrast-enhanced arthro-MRI with the question of cartilage or labral damage.

RESULTS AND CONCLUSIONS

We included 51 patients with a mean age of 35.25. According to the examination algorithm, asphericity was present in all patients via ultrasonography. The average anterior alpha angle (AAA) determined in ultrasonography was 43.49°. The average AAA on the arthro-MRI was 44.19°. The mean anterior head neck offset (AHNO) in ultrasound was 5.27 mm, and in arthro-MRI, it was 5.36 mm. Arthro-MRI confirmed a bump in 47 patients and a talization disorder in 4 patients. In 49 patients, a labral lesion was found, with one being a re-rupture. Furthermore, in one patient, labral degeneration was identified. Cartilage damage to the hip joint was found in 25 patients. Two patients had neither labral nor cartilage damage in the arthro-MRI. In our study, sonographically confirmed asphericity of the head-neck junction was found in 49 cases, which was associated with further pathology and, according to the current doctrine, was attributable to the FAI and required surgical intervention. This study shows that the detection of a pathologic head and neck contour via ultrasound in combination with positive clinical signs, as present in FAI, is associated with chondrolabral lesions detected via arthro-MRI in 96.1% of cases.

Running Mechanics After Repeated Sprints in Femoroacetabular Impingement Syndrome, Cam Morphology, and Controls

BACKGROUND

People with femoroacetabular with femoroacetabular impingement syndrome (FAIS) often report pain during sports involving repeated sprinting. It remains unclear how sports participation influences running biomechanics in individuals with FAIS.

HYPOTHESIS

Changes in running biomechanics and/or isometric hip strength after repeated sprint exercise would be greatest in individuals with FAIS compared with asymptomatic individuals with (CAM) and without cam morphology (Control).

STUDY DESIGN

Controlled laboratory study.

LEVEL OF EVIDENCE

Level 3.

METHODS

Three-dimensional hip biomechanics during maximal running (10 m) and hip strength were measured in 49 recreationally active individuals (FAIS = 15; CAM = 16; Control = 18) before and after repeated sprint exercise performed on a nonmotorized treadmill (8-16 × 30 m). Effects of group and time were assessed for biomechanics and strength variables with repeated-measures analyses of variance. Relationships between hip pain (Copenhagen Hip and Groin Outcome Score) and changes in hip moments and strength after repeated sprint exercise were determined using Spearman's correlation coefficients (ρ).

RESULTS

Running speed, hip flexion angles, hip flexion and extension moments, and hip strength in all muscle groups were significantly reduced from pre to post. No significant between-group differences were observed before or after repeated sprint exercise. No significant relationships (ρ = 0.04-0.30) were observed between hip pain and changes in hip moments or strength in the FAIS group.

CONCLUSION

Changes in running biomechanics and strength after repeated sprint exercise did not differ between participants with FAIS and asymptomatic participants with and without cam morphology. Self-reported pain did not appear to influence biomechanics during running or strength after repeated sprint exercise in participants with FAIS.

CLINICAL RELEVANCE

A short bout of repeated sprinting may not elicit changes in running biomechanics in FAIS beyond what occurs in those without symptoms. Longer duration activities or activities requiring greater hip flexion angles may better provoke pathology-related changes in running biomechanics in people with FAIS.

Hip muscle strength in male and female patients with femoroacetabular impingement syndrome: Comparison to healthy controls and athletes

OBJECTIVES

To examine hip muscle strength deficits in patients with femoroacetabular impingent syndrome (FAIS), with special emphasis on potential sex- and comparison-related (between-subject vs within-subject) differences.

DESIGN

Cross-sectional comparative study.

PARTICIPANTS

Forty FAIS patients (20 women), 40 healthy controls (20 women) and 40 athletes (20 women).

MAIN OUTCOME MEASURES

Hip abduction, adduction and flexion isometric strength was tested using a commercially-available dynamometer. Two between-subject comparisons (FAIS patients vs controls and FAIS patients vs athletes) and one within-subject comparison (inter-limb asymmetry) of strength deficits were conducted, based on the calculation of respective percent differences.

RESULTS

For all hip muscle groups, women were 14-18% weaker than men (p < 0.001), but no sex-related interactions were observed. For all hip muscle groups, FAIS patients were 16-19% weaker than controls (p = 0.001) and 24-30% weaker than athletes (p < 0.001). For FAIS patients, the involved hip abductors were 8.5% weaker than the uninvolved ones (p = 0.015), while no inter-limb asymmetry was observed for the other hip muscles.

CONCLUSION

Sex had no influence on hip muscle strength deficits in FAIS patients while a major impact of comparison method/group was observed. Hip abductors showed consistent deficits for all comparison methods, suggestive of a possible greater impairment compared to hip flexors and adductors.

Arthroscopic Decompression of the Anterior Inferior Iliac Spine

Background

Pathologic contact between the femoral neck and anterior inferior iliac spine (AIIS or subspine) often occurs concomitantly with femoroacetabular impingement, contributing to hip pain and dysfunction1-4. We perform arthroscopic AIIS decompression to alleviate this source of extra-articular impingement and eliminate a potential cause of persistent pain following primary hip arthroscopy5-7.

Description

After identifying abnormal AIIS morphology on preoperative false-profile radiographs and/or 3D computed tomography, we utilize a beaver blade to make a small incision in the proximal capsule and rectus femoris tendon. This peri-capsulotomy window grants access to the subspine region. We then shuttle an arthroscopic burr into place within this window and begin debriding the subspine deformity under direct visualization. Fluoroscopy is utilized intraoperatively to ensure adequate resection, using intraoperative false-profile views achieved by canting the C-arm approximately 40°. Resection is considered adequate when the AIIS deformity is no longer readily apparent on false-profile views and when intraoperative range-of-motion testing confirms no further impingement with hip hyperflexion.

Alternatives

Femoroacetabular impingement can be treated nonoperatively with use of physical therapy and activity modification8; however, outcomes following nonoperative treatment are inferior to those following hip arthroscopy, according to various studies9-12. There are no known alternative treatments specific to subspine impingement.

Rationale

As patients with subspine deformities progress through hip flexion, the femoral neck collides with the AIIS, limiting range of motion. As such, subspine deformities have been shown to be more common in dancers and other high-flexion athletes13,14. Additionally, studies have demonstrated that low femoral version of <5° is associated with increased contact between the distal femoral neck and the AIIS. This pathologic contact can occur even in the absence of an obvious subspine deformity15. In both of these patient populations, surgeons should have a high suspicion for subspine impingement, and a subspine decompression should be performed during hip arthroscopy in order to maximize patient outcomes.

Expected Outcomes

This is a safe procedure that, if performed when indicated, can improve outcomes following primary hip arthroscopy. A recent systematic review found a pooled complication risk of 1.1%, a pooled revision risk of 1.0%, and significant postoperative improvements in patient-reported outcome measures16.

Important Tips

Suspect subspine impingement in high-flexion athletes and patients with low femoral version, even in the absence of an obvious deformity.Ensure adequate visualization of the entire subspine deformity by creating a pericapsular window.Confirm thorough resection with use of fluoroscopic imaging intraoperatively, including false-profile views demonstrating absent subspine deformity.

Acronyms and Abbreviations

FAI = femoroacetabular impingementAP = anteroposterior, refers to the technique used to obtain one of the pelvic radiographs3D CT = three-dimensional computed tomographyLCEA = lateral center-edge angle, a measurement used to quantify severity of hip dysplasiaOR = operating roomAlpha = alpha angle, a measurement used to measure femoral head-neck offset and assess the severity of a cam deformityIc = iliocapsularisRFd = direct head of rectus femorisRFr = reflected head of rectus femorisCap = hip capsuleGMi = gluteus minimusmHHS = modified Harris Hip ScoreHOS-ADL = Hip Outcome Score - Activities of Daily LivingHOS-SSS = Hip Outcome Score - Sports Specific Subscale.

Inflammaging and Osteoarthritis

Osteoarthritis is a highly prevalent disease particularly in subjects over 65 years of age worldwide. While in the past it was considered a mere consequence of cartilage degradation leading to anatomical and functional joint impairment, in recent decades, there has been a more dynamic view with the synovium, the cartilage, and the subchondral bone producing inflammatory mediators which ultimately lead to cartilage damage. Inflammaging is defined as a chronic, sterile, low-grade inflammation state driven by endogenous signals in the absence of infections, occurring with aging. This chronic status is linked to the production of reactive oxygen species and molecules involved in the development of age-related disease such as cancer, diabetes, and cardiovascular and neurodegenerative diseases. Inflammaging contributes to osteoarthritis development where both the innate and the adaptive immune response are involved. Elevated systemic and local inflammatory cytokines and senescent molecules promote cartilage degradation, and antigens derived from damaged joints further trigger inflammation through inflammasome activation. B and T lymphocyte populations also change with inflammaging and OA, with reduced regulatory functions, thus implicating self-reactivity as an additional mechanism of joint damage. The discovery of the underlying pathogenic pathways may help to identify potential therapeutic targets for the management or the prevention of osteoarthritis. We will provide a comprehensive evaluation of the current literature on the role of inflammaging in osteoarthritis and discuss the emerging therapeutic strategies.

[Preoperative MR imaging for hip dysplasia : Assessment of associated deformities and intraarticular pathologies]

BACKGROUND

Developmental dysplasia of the hip (DDH) is a known reason for hip pain for adolescents and young adults. Preoperative imaging is increasingly recognized as an important factor due to the recent advances in MR imaging.

OBJECTIVES

The aim of this article is to give an overview of preoperative imaging for DDH. The acetabular version and morphology, associated femoral deformities (cam deformity, valgus and femoral antetorsion) and intraarticular pathologies (labrum and cartilage damage) and cartilage mapping are described.

METHODS

After an initial evaluation with AP radiographs, CT or MRI represent the methods of choice for the preoperative evaluation of the acetabular morphology and cam deformity, and for the measurement of femoral torsion. Different measurement techniques and normal values should be considered, especially for patients with increased femoral antetorsion because this could lead to misinterpretation and misdiagnosis. MRI allows analysis of labrum hypertrophy and subtle signs for hip instability. 3D MRI for cartilage mapping allows quantification of biochemical cartilage degeneration and yields great potential for surgical decision-making. 3D-CT and, increasingly, 3D MRI of the hip to generate 3D pelvic bone models and subsequent 3D impingement simulation can help to detect posterior extraarticular ischiofemoral impingement.

RESULTS AND DISCUSSION

Acetabular morphology can be divided in anterior, lateral and posterior hip dysplasia. Combined osseous deformities are common, such as hip dysplasia combined with cam deformity (86%). Valgus deformities were reported in 44%. Combined hip dysplasia and increased femoral antetorsion can occur in 52%. Posterior extraarticular ischiofemoral impingement between the lesser trochanter and the ischial tuberosity can occur in patients with increased femoral antetorsion. Typically, labrum damage and hypertrophy, cartilage damage, subchondral cysts can occur in hip dysplasia. Hypertrophy of the muscle iliocapsularis is a sign for hip instability. Acetabular morphology and femoral deformities (cam deformity and femoral anteversion) should be evaluated before surgical therapy for patients with hip dysplasia, considering the different measurement techniques and normal values of femoral antetorsion.

Hip Labral Morphological Changes in Patients with Femoroacetabular Impingement Speed Up the Onset of Early Osteoarthritis

Over the last decade, evidence has mounted for a prominent etiologic role of femoroacetabular impingement (FAI) in the development of early hip osteoarthritis (OA). The aim of this study was to compare the ultrastructure and tissue composition of the hip labrum in healthy and pathological conditions, as FAI and OA, to provide understanding of structural changes which might be helpful in the future to design targeted therapies and improve treatment indications. We analyzed labral tissue samples from five healthy multi-organ donors (MCDs) (median age, 38 years), five FAI patients (median age, 37 years) and five late-stage OA patients undergoing total hip replacement (median age, 56 years). We evaluated morpho-functional by histology and transmission electron microscopy. Extracellular matrix (ECM) structure changes were similar in specimens from FAI compared to those from patients with OA (more severe in the latter) showing disorganization of collagen fibers and increased proteoglycan content. In FAI and in OA nuclei the chromatin was condensed, organelle degenerated and cytoplasm vacuolized. Areas of calcification were mainly observed in FAI and OA labrum, as well as apoptotic-like features. We showed that labral tissue of patients with FAI had similar pathological alterations of tissue obtained from OA patients, suggesting that FAI patients might have high susceptibility to develop OA.

Outcomes of Arthroscopic Decompression of the Anterior Inferior Iliac Spine: A Systematic Review and Meta-analysis

BACKGROUND

Anterior inferior iliac spine (AIIS) impingement has been increasingly recognized as a source of extra-articular impingement and hip pain. However, no aggregate data analysis of patient outcomes after AIIS decompression has been performed.

PURPOSE

To evaluate outcomes after arthroscopic AIIS decompression.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were queried for all English-language studies reporting outcomes of arthroscopic AIIS decompression performed in isolation or in conjunction with hip impingement correction surgery. After screening, 10 articles were included. The indications for AIIS decompression were recorded, and weighted mean improvements in patient-reported outcome (PRO) scores, complication rates, and revision rates were calculated.

RESULTS

A total of 547 patients (311 women; 57%) were identified, with a total of 620 operative hips. The mean age was 28.42 ± 5.6 years, and the mean follow-up was 25.22 ± 11.1 months. A total of 529 hips (85%) underwent AIIS decompression, 530 hips (85%) underwent femoral osteochondroplasty, and 458 hips (74%) underwent labral repair. Of the patients, 13% underwent bilateral AIIS decompression. The mean modified Harris Hip Score improved from 61.3 ± 6.9 to 88.7 ± 4.7 postoperatively (change, 27.4 ± 5.7 points; P < .001), the Hip Outcome Score-Activities of Daily Living improved from 67.2 ± 10.6 to 91.1 ± 3.2 postoperatively (change, 24.0 ± 8.0 points; P = .001), and the Hip Outcome Score-Sports Specific Subscale improved from 36.8 ± 19.2 to 82.8 ± 3.8 postoperatively (change, 46.0 ± 18.2 points; P = .002). The pooled risk of postoperative complications was 1.1% (95% CI, 0.1%-2.1%), and the pooled risk of needing revision surgery was 1.0% (95% CI, 0.1%-2.0%). No complication was directly attributed to the AIIS decompression portion of the procedure.

CONCLUSION

PROs improved significantly after hip arthroscopy with AIIS decompression, with a low risk of postoperative complications and subsequent revision surgeries. Failure to identify extra-articular sources of hip pain in outcomes of femoroacetabular impingement syndrome, including from the AIIS, could lead to poorer outcomes and future revision surgery.

Acetabular cartilage delamination: performance of MRI using arthroscopy as the standard of reference

BACKGROUND

Femoroacetabular impingement (FAI) frequently leads to acetabular chondral delamination. Early identification and treatment of these cases is crucial to prevent further damage to the hip.

PURPOSE

To evaluate the accuracy of morphological signs of cartilage acetabular delamination in non-arthrographic magnetic resonance imaging (MRI) using intra-articular arthroscopic findings in patients undergoing FAI surgery.

MATERIAL AND METHODS

All hip MRI scans were assessed individually by three independent radiologists. Images were assessed for signs of delamination including the presence of a linear area of bright signal intensity along the acetabular subchondral bone and an area of darker tissue at the surface of the acetabular cartilage. All FAI patients underwent surgery; arthroscopy served as the standard of reference.

RESULTS

The mean age of participants was 36.1±10.9 years with 36 (48.6%) women. In the FAI group, arthroscopic surgery showed acetabular chondral delamination in 37 hips. In all hips (including the controls), MRI signs of acetabular cartilage delamination showed an average sensitivity across the three raters of 73.0% with a specificity of 71.0%. In a separate analysis of only the FAI patients, a slightly higher sensitivity (77.7%) but lower specificity (66.7%) was demonstrated. The interrater reliability showed a moderate agreement (average [k]) across the raters (0.450).

CONCLUSION

Performance of non-arthrographic MRI in diagnosing acetabular chondral delamination showed good results, yet inter-observer reproducibility among different radiologists was only moderate. Our results suggest that an increased level of awareness, for signs of delamination using MRI, will be helpful for detecting chondral delamination in patients with a history of FAI.

Patient-Perceived Outcomes Improve Faster Than Hip Strength in Recovery After Surgical Correction for Symptomatic Femoroacetabular Impingement

Background: Patients with symptomatic femoroacetabular impingement (FAI) have hip strength deficits, instability, and increased risk for concomitant injury. While surgical intervention is an effective method of treatment for FAI, more information is needed about the recovery process. Purposes: We sought to understand how patients with FAI recover from surgical correction in the short term. Do patients' perceptions of improvement correspond with measured improvements in hip strength? Methods: We conducted a prospective cohort study of 17 patients (11 male, age range: 16-38 years) who were diagnosed with symptomatic FAI at a single surgeon's practice. Hip strength (flexion, extension, and abduction) was measured preoperatively and at 14, 26, and 52 weeks postoperatively. Patient-reported outcomes using the modified Harris Hip Score (mHHS) and Hip Outcome Osteoarthritis Score (HOOS) subscales were measured at the same time points and at 2 weeks postoperatively. Results: Compared with preoperative values, there was a significant increase in postoperative values at 26 and 52 weeks in normalized isokinetic hip extension (29% and 38%, respectively) and normalized hip abduction (48% and 55%, respectively). No differences in strength were observed at 14 weeks. Modified Harris Hip Score and all HOOS subscales were decreased by 2 weeks postoperatively, and by 14 weeks mHHS improved by 21%, and HOOS subscales improved as well (activities of daily living by 18%, pain by 34%, quality of life by 69%, sport and recreation by 36%, and symptoms by 28%). Conclusion: We observed that patient-reported outcomes including symptoms, function, and satisfaction improved at 14 weeks, while objective measures of hip strength improved at 26 weeks following surgical correction of FAI. More rigorous study is indicated.

Olympic fencer with femoroacetabular impingement syndrome uses active rehabilitation to avoid surgery: A case report

INTRODUCTION

Femoroacetabular impingement (FAI) syndrome is a musculoskeletal condition characterized by hip symptoms. Conservative therapy is indicated prior to surgical intervention. However, no literature has described conservative management of FAI in detail. This report provides a detailed active rehabilitation plan for an elite athlete with FAI to guide future research and clinicians.

CASE PRESENTATION

A 30-year-old male Olympic fencing athlete presented with unilateral hip pain less than 1 year prior to the Olympic Games. Radiographic imaging demonstrated bilateral cam morphology. Hip mobilizations and stretching did not provide a meaningful pain reduction. Cortisone injection was then suggested prior to the Games where surgery was suggested following the Games.

MANAGEMENT AND OUTCOME

Active rehabilitative exercises targeted motor control of the lumbo-pelvic-hip complex, which led to significant pain reduction and full return to sport. Surgical intervention and cortisone injections were deemed unnecessary due to resolution of symptoms.

CONCLUSION

Athletes with FAI syndrome may benefit from specific active rehabilitation exercises. Future clinical trials should explore rehabilitative exercises that address improved motor control to manage individuals with FAI syndrome.

Which hip morphology measures and patient factors are associated with age of onset and symptom severity in femoroacetabular impingement syndrome?

BACKGROUND

Bony morphology is central to the pathomechanism of femoroacetabular impingement syndrome (FAIS), however isolated radiographic measures poorly predict symptom onset and severity. More comprehensive morphology measurement considered together with patient factors may better predict symptom presentation. This study aimed to determine the morphological parameter(s) and patient factor(s) associated with symptom age of onset and severity in FAIS.

METHODS

99 participants (age 32.9 ± 10.5 years; body mass index (BMI 24.3 ± 3.1 kg/m²; 42% females) diagnosed with FAIS received standardised plain radiographs and magnetic resonance scans. Alpha angle in four radial planes (superior to anterior), acetabular version (AV), femoral torsion, lateral centre-edge, anterior centre-edge (ACEA) and femoral neck-shaft angles were measured. Age of symptom onset (age at presentation minus duration of symptoms), international Hip Outcome Tool-33 (iHOT-33) and modified UCLA activity scores were recorded. Backward stepwise regression assessed morphological parameters and patient factors (age, sex, BMI, symptom duration, annual income, private/public healthcare system accessed) to determine variables independently associated with onset age and iHOT-33 score.

RESULTS

Earlier symptom onset was associated with larger superoanterior alpha angle (p = 0.007), smaller AV (p = 0.023), lower BMI (p = 0.010) and public healthcare system access (p = 0.041) (r² = 0.320). Worse iHOT-33 score was associated with smaller ACEA (p = 0.034), female sex (p = 0.040), worse modified UCLA activity score (p = 0.010) and public healthcare system access (p < 0.001) (r² = 0.340).

CONCLUSIONS

Age of symptom onset was chiefly predicted by femoral and acetabular bony morphology measures, whereas symptom severity predominantly by patient factors. Factors measured explained a small amount of variance in the data; additional unmeasured factors may be more influential.

Evolution of Hip Muscles Strength in Femoroacetabular Impingement Patients Treated by Arthroscopy or Surgical Hip Dislocation: A Retrospective Exploratory Study

Hip arthroscopy and surgical hip dislocation (SHD) can be adequate surgical options for patients suffering from femoroacetabular impingement (FAI) syndrome, but there is to date no published data on their impact on hip muscles strength. The purpose of this retrospective study was, therefore, to evaluate it on a consecutive series of 50 FAI patients treated either by arthroscopy (n = 29, aged 27.4 ± 7.5 years, 76% of women) or SHD (n = 21, aged 25.9 ± 6.5 years, 38% of women) at La Tour Hospital between 2020 and 2021. The bilateral isometric strengths of eight hip-related muscles were evaluated before and three months after surgery (halfway through the rehabilitation program). For arthroscopy, a statistically significant (p < 0.05) reduction in hip muscles strength could be noted on the operated hamstrings (1.49 ± 0.43 vs. 1.39 ± 0.38 Nm/kg), flexors (1.88 ± 0.46 vs. 1.73 ± 0.41 Nm/kg), abductors (1.97 ± 0.42 vs. 1.72 ± 0.40 Nm/kg) and external rotators (1.17 ± 0.40 vs. 1.04 ± 0.37 Nm/kg). The abductors were the most affected muscles, with 45% of the patients suffering from a strength reduction ≥15%. The non-operated external rotators were also affected but to a lesser extent (1.21 ± 0.38 vs. 1.10 ± 0.36 Nm/kg). For SHD, a statistically significant strength reduction could be noted on the operated extensors (2.28 ± 0.84 vs. 2.05 ± 0.70 Nm/kg), abductors (1.87 ± 0.49 vs. 1.65 ± 0.41 Nm/kg), quadriceps (2.96 ± 0.92 vs. 2.44 ± 0.89 Nm/kg), external rotators (1.16 ± 0.42 vs. 0.93 ± 0.36 Nm/kg) and internal rotators (1.26 ± 0.38 vs. 0.96 ± 0.30 Nm/kg). The internal rotators were the most affected muscles, with 75% of the patients suffering from a strength reduction ≥15%. To conclude, particular attention should be paid to operated abductors for patients treated by arthroscopy as well as operated internal/external rotators, abductors and quadriceps for those treated by surgical hip dislocation. It reinforces that a rehabilitation method based on isolated muscle reinforcement and functional exercises that goes beyond three postoperative months is needed.

Increased Synovial CD14 mRNA Expression and Proportion of CD14high Subsets in Early-Stage Hip Osteoarthritis: Propensity Matched Score Analysis

The pathophysiology of early-stage hip osteoarthritis (EOA) is not fully understood. Although a previous study in an age-unmatched cohort reported that the number of macrophages was increased in knee EOA compared to late OA (LOA), it remained unclear whether increased macrophages in EOA accurately reflect EOA pathology. We investigated the differences in CD14 expression levels between EOA and LOA using age-unmatched and -matched cohorts. Synovial tissues were obtained from 34 EOA (Tönnis grades 0 and 1) and 80 LOA (Tönnis grades 2 and 3) patients. To correct for differences in demographics between patients with LOA and EOA, we also created propensity score-matched cohorts (16 EOA and 16 LOA). CD14 expression and its association with pain was estimated in LOA and EOA before and after propensity matching. We performed flow cytometry on tissues from the 16 patients, with 8 from each group, to assess for CD14+ subsets in the cells. The CD14 expression in EOA was higher than that in LOA both before and after propensity matching. The proportion of CD14high subsets in EOA was higher than that in LOA. The CD14 expression was associated with pain in EOA before matching. However, no difference was observed between the pain and CD14 expression after matching in EOA. The increased CD14 expression and the proportion of CD14high subsets may be important features associated with hip EOA pathology. To accurately compare early and late OA, the analysis of a propensity score-matched cohort is necessary.

Does Femoral Osteoplasty Improve Long-term Clinical Outcomes and Survivorship of Hip Arthroscopy? A 15-Year Minimum Follow-up Study

BACKGROUND

Although femoral osteoplasty is common practice in treating cam-type femoroacetabular impingement (FAI), long-term data are lacking that support the ability of this procedure to optimize outcomes and alter natural history.

PURPOSE

To compare long-term clinical outcomes and survivorship of treatment for symptomatic FAI via arthroscopic correction of labral or chondral pathology with and without femoral osteoplasty.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective cohort study was performed across 2 consecutive cohorts of patients with isolated cam-type FAI who underwent hip arthroscopic treatment of labral or chondral pathology without femoral osteoplasty (HS group) or with femoral osteoplasty (HS-OST group). These unique cohorts were established at a distinct transition time in our practice before and after adoption of femoral osteoplasty for treatment of FAI. Clinical outcomes were measured using the modified Harris Hip Score (mHHS). Kaplan-Meier analysis was used to assess for total hip arthroplasty (THA)-free and reoperation-free survivorship.

RESULTS

The final HS group included 17 hips followed for 19.7 ± 1.2 years, and the final HS-OST group included 23 hips followed for 16.0 ± 0.6 years. No significant patient or morphological differences were found between groups. Compared with the HS group, the HS-OST group had significantly higher final mHHS (82.7 vs 64.7 for HS-OST vs HS, respectively; P = .002) and mHHS improvement (18.4 vs 6.1; P = .02). The HS-OST group also had significantly greater 15-year THA-free survivorship versus the HS group (78% vs 41%, respectively; P = .02) and reoperation-free survivorship (78% vs 29%; P = .003).

CONCLUSION

This study demonstrated superior long-term clinical outcomes and survivorship with combined arthroscopy and femoral osteoplasty compared with hip arthroscopy alone. These long-term data strongly support the practice of femoral osteoplasty in patients with cam FAI morphologies and suggest that this treatment alters the natural history of FAI at long-term follow-up.

Factors Associated With Disease Progression in the Contralateral Hip of Patients With Symptomatic Femoroacetabular Impingement: A Minimum 5-Year Analysis

BACKGROUND

Femoroacetabular impingement (FAI) is one of the most common causes of hip osteoarthritis, yet the factors controlling disease progression are poorly understood.

PURPOSE

To investigate rates of initial and subsequent symptoms in the contralateral hip of patients with FAI, and identify predictors of disease progression (symptom development and surgical intervention) in the contralateral hip.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

This prospective study included a minimum 5-year follow-up of the contralateral hip in 179 patients undergoing FAI surgery. Symptoms (moderate pain) and surgical progression were monitored. Univariate and multivariate analyses compared patient-specific and imaging characteristics of symptomatic patients with those who remained asymptomatic to identify factors associated with disease progression.

RESULTS

A total of 150 patients (84% follow-up) were followed for a mean of 7.1 years (range, 5-11 years). Thirty-nine of these patients (26% [39/150]) had contralateral hip symptoms at initial evaluation. Of those without contralateral hip symptoms at initial evaluation, 32% (36/111) had developed contralateral hip symptoms by latest follow-up. Those who developed symptoms during the study period had a lower anteroposterior head-neck offset ratio (0.153 vs 0.165; P = .005), decreased total arc of rotation in 90° of flexion (39.9° vs 51.1°; P = .005), and decreased external rotation in 90° of flexion (28.6° vs 37.1°; P = .003) compared with those who never developed symptoms. Age, sex, body mass index, alpha angle, lateral center-edge angle, internal rotation in flexion, and University of California, Los Angeles (UCLA), activity score were similar between these groups. Those with contralateral symptoms at initial evaluation progressed to contralateral surgery at a rate of 41% (16/39) and those who developed contralateral symptoms during the study period progressed to contralateral surgery at a rate of 28% (10/36). Among those with contalateral hip symptoms (either present initially or developed during study period)), younger age (24.6 vs 34.1 years; P < .001) and baseline UCLA activity score ≥9 (P = .003) were associated with progression to surgery. By Kaplan-Meier analysis, 64%, 54%, and 48% of patients remained free of contralateral hip symptoms at 2, 5, and 10 years.

CONCLUSION

At a mean follow-up of 7.1 years, significant symptoms in the contralateral hip of patients with FAI were present in approximately 50% of patients. FAI disease progression (symptom development and surgical intervention) was associated with decreased hip rotation arc, decreased external rotation, and decreased head-neck offset ratio. In symptomatic patients, younger age and UCLA activity score ≥9 were associated with progression to surgery. These findings represent important factors for patient counseling and risk modeling in FAI.

Analysis of factors affecting the time for implantation of a total hip arthroplasty in patients with symptomatic primary and secondary hip osteoarthritis

BACKGROUND

Many studies have identified factors associated with an unfavourable clinical outcome or an early conversion to total hip arthroplasty (THA) after joint-preserving treatment. We analysed the effect and reliability of different factors on the age at which THA becomes necessary.

METHODS

Hip joint radiographs of 2485 cases were evaluated using the lateral centre-edge angle (LCEA) and acetabulum angle (ACA) as well as the alpha angle to describe the femoral head shapes. Regressions were performed using patient's age at the time of THA and body mass index (BMI) as well as LCEA and ACA. Multiple linear regressions were used to create a formula comprising factors that significantly correlated with patient age at the time of joint replacement surgery.

RESULTS

The BMI, LCEA, and ACA showed significant correlations with the age of THA implantation (p < 0.001). Multiple linear regressions produced the following formula: age (THA) = 72.40-0.40 × BMI + 0.20 × LCEA-0.18 × ACA. BMI showed a stronger impact on the age of end-stage osteoarthritis than the ACA. The formula explained 12.1% of the distributing data (r²). Surprisingly, the alpha angle did not show an impact on the age of THA surgery.

CONCLUSIONS

BMI had the greatest impact on patient's age at the time of THA, followed by the characteristic radiological angles for hip dysplasia. The resulting formula could emphasise and visualise the significant impact of these factors. However, despite the calculation being based on 2485 cases, the calculated validity of 12.1% was limited.

Accuracy of Computer Navigation-Assisted Arthroscopic Osteochondroplasty for Cam-Type Femoroacetabular Impingement Using the Model-to-Image Registration Method

BACKGROUND

Precise osteochondroplasty is important in arthroscopic hip surgery for cam-type femoroacetabular impingement (FAI). Although computer-assisted surgery with a navigation system may enhance the accuracy of arthroscopic osteochondroplasty, few clinical studies have assessed its accuracy.

PURPOSE

To evaluate the accuracy of arthroscopic osteochondroplasty by a computed tomography (CT)-based navigation system for cam-type FAI, using 3-dimensional (3D) reconstruction with more detail compared with previous methods.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Twenty patients (14 men and 6 women) who underwent navigation-assisted arthroscopic surgery for cam-type FAI were included. The preoperative 3D model of the femur was constructed from each patient's CT data, and a planned model with virtual cam resection was generated. A femoral model was reconstructed from CT data postoperatively. The 3 models for each patient were overlaid using a 3D model registration method. Then, the contours of the bone resection area of each model were compared by measuring them. To measure the deviation between planned and actual bone resections, 4 cross-sectional images of the 3 femoral models were set at one-quarter intervals from the femoral head radius. All measurements were based on clockface lines set around the femoral neck axis at 30-minute intervals. Differences between the planned and postoperative contour lines were deemed resection deviations.

RESULTS

All cam resections were performed in the anterior half of the region of interest. Therefore, only the anterior half (48 points) of the 96 points per case were analyzed. In 876 (91.3%) points of the total measurement points (960 points/20 cases), the error in resection depth was within 3 mm. Overresection was observed at 35 (3.6%) points and underresection at 49 (5.1%) points. The observed maximum deviations from the planned models were 6.3 mm overresection and -7.1 mm underresection. The alpha angles of the postoperative model at the posterior 9- to 3-o'clock position were <55° in all patients.

CONCLUSION

Navigation-assisted arthroscopic osteochondroplasty showed favorable accuracy. Underresection was more frequent than overresection on the anterosuperior side of the femur, despite assistance of the navigation system.

Patient-Specific Risk Factors Exist for Hip Fractures After Arthroscopic Femoroacetabular Impingement Surgery, But Not for Dislocation—An Analysis of More Than 25,000 Hip Arthroscopies

Purpose

To identify postoperative complications and risk factors associated with hip fracture and dislocation following primary arthroscopic surgical management of femoroacetabular impingement (FAI) syndrome.

Methods

MarketScan was queried to identify patients who underwent FAI surgery from 2007 to 2016. Patients were stratified into 2 groups: acetabuloplasty only or femoroplasty only. A subanalysis of combined acetabuloplasty and femoroplasty also was undertaken. Surgical outcomes were followed postoperatively for 180 days. Multivariate logistic regression was used to control for with an alpha value of 0.05 set as significant.

Results

This study identified 13,809 patients (mean age, 36.3 years) who underwent primary acetabuloplasty or femoroplasty. We also identified 10,026 patients who underwent both procedures. Postoperative complication rates were similar between the cohorts (acetabuloplasty 17.1%, femoroplasty 19.9%, P = .0622). Rates of hip fracture (femoroplasty: 2.4% vs acetabuloplasty: 2.0%, P = .0302) and heterotopic ossification (femoroplasty: 11.3% vs acetabuloplasty: 8.8%, P < .0001) were greater in the femoroplasty-only cohort. Combined acetabuloplasty and femoroplasty was associated with the greatest complication burden of 21.6% (P < .0001). After multivariate regression, differences in age, sex, comorbid status, or procedure type did not influence odds in risk for postoperative hip dislocation. Adjusted data showed that neither femoroplasty nor acetabuloplasty influenced odds of hip fracture (P > .05). Patients who were aged younger than 20 years old were significantly less likely to fracture their hips postoperatively than patients aged 60+ years (odds ratio 0.3, 95% confidence interval 0.1-0.8). Hypertension was independently associated with increased odds of hip fracture (odds ratio 1.7, 95% confidence interval 1.2-3.5).

Conclusions

Older age, male sex, and hypertension all carry increased risk for a hip fracture following acetabuloplasty or femoroplasty. Patient- and procedure-specific factors that could be assessed with this database did not influence risk for hip dislocation.

Level of Evidence

Level III; retrospective comparative observation trial.

Arthroscopic hip surgery offers better early patient-reported outcome measures than targeted physiotherapy programs for the treatment of femoroacetabular impingement syndrome: a systematic review and meta-analysis of randomized controlled trials

Targeted physiotherapy programs (TPP), and surgery, using either open surgical hip dislocation or hip arthroscopy (HA), are the treatment modalities available for femoroacetabular impingement syndrome (FAIS). Randomized controlled trials have recently been performed to compare these treatment options. This review was performed to provide a focused synthesis of the available evidence regarding the relative value of treatment options. A systematic search was performed of Medline, Embase, Cochrane Library and ClinicalTrials.gov databases. Inclusion criteria were randomized controlled trials comparing treatment methods. The Cochrane Risk of Bias assessment tool (RoB2) was used to assess the selected studies. A meta-analysis was performed between homogenous studies. Four trials were identified including 749 patients (392 males). The mean ages of the cohorts ranged between 30.1 and 36.2 years old. Three hundred thirty-five patients underwent HA by 46 surgeons among all trials. Fifty-two patients crossed over from the TPP to the HA group. One of the trials was found to have a high risk of bias, while the other three were between low risk and some concerns. The iHOT-33 was the most commonly used patient-reported outcome measure followed by the HOS ADL and EQ-5D-5L. Others scores were also identified. Scores from two trials could be pooled together for meta-analysis. Apart from SF-12 and GRC, all other scores have shown significantly better outcomes with HA in comparison to TPP at 8- and 12-months follow-up points. HA offers better patient-reported outcomes than TPP for management of FAIS at 8- and 12-months follow-up.

Five-Year Follow-up After Hip Arthroscopic Surgery in the Horsens-Aarhus Femoroacetabular Impingement (HAFAI) Cohort

Background:

Patients with femoroacetabular impingement syndrome (FAIS) are offered hip arthroscopic surgery to decrease hip pain, improve their function, and decrease development of hip osteoarthritis (OA). Nonetheless, long-term follow-up data are few.

Purpose:

To investigate patient-reported outcomes, clinical tests, reoperations, and radiographic status 5 years after primary hip arthroscopy in patients with FAIS.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 60 patients (age, 36 ± 9 years; 63% female) diagnosed with FAIS were included in the study and followed for 5 years after hip arthroscopy. Follow-up included Copenhagen Hip and Groin Outcome Score (HAGOS); Hip Sports Activity Scale; and clinical tests (flexion, adduction, internal rotation [FADIR]; flexion, abduction, external rotation [FABER]; and psoas muscle/tendon major pain provocation). Radiographic evaluation included lateral joint-space width (LJSW) and Tönnis classification for hip OA. Reoperations and conversion to total hip replacement (THR) were recorded. We calculated the proportion of patients who exceeded the minimal important change (MIC), achieved the Patient Acceptable Symptom State (PASS), and were within the 95% reference interval of age- and sex-matched persons with no hip problems. Changes were investigated using paired t tests.

Results:

Compared with preoperatively, all HAGOS subscales were improved substantially 5 years after surgery (mean, ≥21 points; P < .001), and 67% to 89% of patients reported improvements exceeding MIC. Between 56% and 80% achieved PASS, but only 7% to 24% reached the 95% reference interval for the HAGOS subscales. A total of 36% had a positive FADIR test and 25% had a positive FABER test, which were improvements compared with preoperatively (P < .001 for both). Patients with a positive FADIR test had significantly worse HAGOS subscales. Six patients (10%) had a THR since their primary hip arthroscopy. In the remaining patients, the mean LJSW was decreased (-0.4 mm; P = .043), and hip OA had worsened in 9 patients (23%; P = .003).

Conclusion:

Five years after surgery, the majority of patients experienced HAGOS improvements exceeding MIC while also showing an acceptable PASS. However, clinical tests, participation in physical activities, and quality of life indicated that many patients still experience hip problems.

Registration:

NCT04590924 (ClinicalTrials.gov identifier).

Bilateral hip arthroscopy for treating femoroacetabular impingement: a systematic review

PURPOSE

Femoroacetabular impingement (FAI) is a hip disorder which can often present bilaterally. The purpose of this systematic review was to explore the current practices for bilateral hip arthroscopy in treating FAI as they relate to outcomes and complications.

METHODS

This review has been conducted according to the guidelines of Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). The electronic databases PubMed, MEDLINE, EMBASE, and CENTRAL (Cochrane Central Register of Controlled Trials) were searched from data inception to October 18th, 2020. The Methodological Index for Non-randomized Studies (MINORS) was used to assess study quality. Data are presented descriptively.

RESULTS

Overall, 19 studies were identified, comprising 957 patients (48.6% male) with a mean age of 27.9 ± 7.1 years and a mean follow-up of 31.7 ± 20.8 months. The majority of patients were treated with a staged bilateral hip arthroscopy (78.5%) with a mean duration between surgeries of 7.1 ± 4.0 months. Significant preoperative-to-postoperative improvements for clinical outcomes such as pain, hip function, and health-related daily living as well as radiographic outcomes were reported in six studies for staged procedures (p < 0.05) and three studies for simultaneous procedures (p < 0.02). Significant improvements in patient-reported outcomes (e.g., HOS-ADL, Pain, HOS-SS, mHHS, and NAHS) were found in favor of those undergoing a shorter delay between surgeries in three studies (i.e., < 3, 10 or 17 months) (p < 0.05) compared to those who had delayed surgeries (i.e., > 3, 10, or 17 months). The overall complication rate was 10.1% (97/957).

CONCLUSIONS

Bilateral surgery for FAI yields improved outcomes postoperatively and complication rates similar to unilateral surgery. The overall complication rate was 10.1% with the most common complication being revision surgery. Staged bilateral surgery is more commonly performed than simultaneous surgery. Clinicians should consider preoperative imaging, clinical history, and patient values when deciding between staged and simultaneous procedures for bilateral FAI surgery. Future studies are required to determine the optimal indications for simultaneous versus staged procedures, as well as the ideal timing between surgeries for the latter.

LEVEL OF EVIDENCE

Level IV.

Hip joint motion does not change one year after arthroscopic osteochondroplasty in patients with femoroacetabular impingement evaluated with dynamic radiostereometry

Purpose

Dynamic radiostereometric analysis (dRSA) enables precise non-invasive three-dimensional motion-tracking of bones for assessment of joint kinematics. Hereby, the biomechanical effects of arthroscopic osteochondroplasty of the hip (ACH) can be evaluated in patients with femoroacetabular impingement (FAI).

The aim was to investigate the pre- and postoperative range of motion (ROM) and the CT bone volume removed (BV) after ACH. We hypothesize increase in ROM 1 year after surgery.

Methods

Thirteen patients (6 female) with symptomatic FAI were included prospectively. The patient’s hips were CT-scanned and CT-bone models were created. Preoperative dRSA recordings were acquired during passive flexion to 90°, adduction, and internal rotation (FADIR). ACH was performed, CT and dRSA were repeated 3 months and 1 year postoperatively. Hip joint kinematics before, and 3 months and 1 year after ACH were compared pairwise. The bone volume removal was quantified and compared to change in ROM.

Results

Mean hip internal rotation, adduction and flexion were all unchanged after ACH at 1-year follow-up (p > 0.84). HAGOS scores revealed improvement of quality of life (QOL) from 32 to 60 (p = 0.02). The BV was between 406 and 1783 mm³ and did not correlate to post-operative ROM.

Conclusions

ACH surgery in FAI patients had no impact of ROM at 1-year follow-up. QOL improved significantly. This indicates that the positive clinical effects reported after ACH might be a result of reduced labral stress and cartilage pressure during end-range motion rather than increased ROM.

Level of evidence

Therapeutic prospective cohort study, level II.

Global, regional, and national burdens of hip osteoarthritis from 1990 to 2019: estimates from the 2019 Global Burden of Disease Study

BACKGROUND

Hip osteoarthritis is a common disabling condition of the hip joint and is associated with a substantial health burden. We assessed the epidemiological patterns of hip osteoarthritis from 1990 to 2019 by sex, age, and socio-demographic index (SDI).

METHODS

Age-standardized rates (ASRs) were obtained for the incidence and disability-adjusted life years (DALYs) of hip osteoarthritis from 1990 to 2019 for 21 regions, encompassing a total of 204 countries and territories. The estimated annual percentage changes (EAPCs) of ASRs were calculated to evaluate the trends in the incidence and DALYs of hip osteoarthritis over these 30 years.

RESULTS

Globally, from 1990 to 2019, the age-standardized incidence rate (ASIR) of hip osteoarthritis increased from 17.02 per 100,000 persons to 18.70 per 100,000 persons, with an upward trend in the EAPC of 0.32 (0.29-0.34), whereas the age-standardized DALY rate increased from 11.54 per 100,000 persons to 12.57 per 100,000 persons, with an EAPC of 0.29 (0.27-0.32). In 2019, the EAPCs of the ASIR and age-standardized DALY rate of hip osteoarthritis were positively associated with the SDI of hip osteoarthritis. In 1990 and 2019, the incidence of hip osteoarthritis was unimodally distributed across different age groups, with a peak incidence in the 60-64-year-old age group, whereas the DALYs increased with age.

CONCLUSIONS

The incidence and DALYs of hip osteoarthritis have been increasing globally. The EAPCs of the ASIR and age-standardized DALY rate were particularly significant in developed regions and varied across nations and regions, indicating the urgent need for governments and medical institutions to increase the awareness regarding risk factors, consequences of hip osteoarthritis.

Preoperative Intra-articular Steroid Injections as Predictors of Hip Arthroscopy: 2-Year Outcomes

BACKGROUND

In patients with femoroacetabular impingement, preoperative diagnostic injections are commonly used to establish a diagnosis of intra-articular pathology. In some cases, intra-articular steroid injections are also used for therapeutic purposes.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine if a positive response to intra-articular steroid injection was predictive of superior outcomes after hip arthroscopy to determine if the response to intra-articular steroid injection was predictive of outcomes after hip arthroscopy. It was hypothesized that a positive response to a preoperative hip injection would be predictive of improved short- to midterm outcomes after hip arthroscopy.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

This was a retrospective study of 208 patients who elected to have ultrasound-guided intra-articular steroid injection before they underwent hip arthroscopy between January 2016 and December 2016. Patients were divided into 2 groups: those who showed improvement in pain after the injection (steroid responder group) and those who showed no response (nonresponder group). The authors compared the preoperative and 2-year postoperative patient-reported outcomes (modified Harris Hip Score [mHHS] and Hip Outcome Score-Activities of Daily Living [HOS-ADL]) and radiographic findings between groups. Clinical endpoints, including rates of revision and conversion to total hip arthroplasty, were also reviewed.

RESULTS

There were 88 patients in the nonresponder group and 120 patients in the responder group, with no significant between-group differences in preoperative descriptive variables. The responder group had significantly higher 2-year mHHS and HOS-ADL, pre- to postoperative change in mHHS and HOS-ADL, percentage of patients achieving the patient acceptable symptomatic state (PASS) on the mHHS, and percentage of patients reaching the minimum clinically important difference and the PASS on the HOS-ADL. There was no difference in Tönnis grade, acetabular labrum articular disruption grade, revision rate, or conversion to total hip arthroplasty between the 2 groups.

CONCLUSION

The response to preoperative intra-articular injection did aid in predicting 2-year patient-reported outcomes of hip arthroscopy for femoroacetabular impingement. Overall, the result of a preoperative intra-articular injection can be a helpful clinical tool for surgical decision-making and counseling patients on expected outcomes after hip arthroscopy.

3D MRI Models of the Musculoskeletal System

Computed tomography (CT) is most commonly used to produce three-dimensional (3D) models for evaluating bone and joint morphology in clinical practice. However, 3D models created from magnetic resonance imaging (MRI) data can be equally effective for comprehensive and accurate assessment of osseous and soft tissue structure morphology and pathology. The quality of 3D MRI models has steadily increased over time, with growing potential to replace 3D CT models in various musculoskeletal (MSK) applications. In practice, a single MRI examination for two-dimensional and 3D assessments can increase the value of MRI and simplify the pre- and postoperative imaging work-up. Multiple studies have shown excellent performance of 3D MRI models in shoulder injuries, in the hip in the setting of femoroacetabular impingement, and in the knee for the creation of bone surface models. Therefore, the utility of 3D MRI postprocessed models is expected to continue to rise and broaden in applications. Computer-based and artificial intelligence-assisted postprocessing techniques have tremendous potential to improve the efficiency of 3D model creation, opening many research avenues to validate the applicability of 3D MRI and establish 3D-specific quantitative assessment criteria. We provide a practice-focused overview of 3D MRI acquisition strategies, postprocessing techniques for 3D model creation, MSK applications of 3D MRI models, and an illustration of cases from our daily clinical practice.

A longitudinal cohort study of adolescent elite footballers and controls investigating the development of cam morphology

Cam morphology describes an asphericity of the femoral head that develops during adolescence, is highly prevalent in athletes, and predisposes individuals to future osteoarthritis. However, it’s aetiology remains poorly understood. The aim of this study was to perform 3-year longitudinal follow-up of a control population and football club academy cohort to compare the change in hip and growth plate anatomy between athletes and controls. MRI and questionnaires were used to characterise change in hip and growth plate anatomy and quantify activity levels. 121 male academy footballers and 107 male and female controls participated at baseline. Footballers experienced significantly greater increases in femoral head asphericity (4.83 degrees (95% CI: 2.84 to 6.82), p < 0.001) than controls. A positive correlation existed between activity levels and change in femoral head morphology (coefficient 0.79, p  ≤  0.001). Greatest morphological change occurred in individuals aged 11–12 years at baseline, with no significant change in individuals aged 14 years and older at baseline. Cam morphology development was secondary to soft tissue hypertrophy and lateral growth plate extension. In conclusion, excessive loading of the hip joint through exercise prior to 14 years of age may result in growth plate adaptations causing cam morphology. Potential interventions may include training type and load modification in young adolescent football players.

Is hip morphology a risk factor for developing hip osteoarthritis? A systematic review with meta-analysis

OBJECTIVE

To appraise the highest evidence on hip morphology as a risk factor for developing hip osteoarthritis (OA).

DESIGN

We searched for studies evaluating the association between radiological hip morphology parameters and the prevalence, incidence or progression of hip OA (based on different radiographic and clinical criteria) in the MEDLINE, EMBASE, Web of Science, Scopus, Cochrane Library and PEDro databases from inception until June 2020. Prospective and cross-sectional studies were separately evaluated. Data are presented as odds ratios (OR) with 95% confidence intervals (CI).

RESULTS

We included 9 prospective and 21 cross-sectional studies in the meta-analysis, and evaluated 42,831 hips from 25,898 individuals (mean age: 59 years). Prospective studies showed that, compared with control hips, hips with cam morphology (alpha angle >60°; OR = 2.52, 95% CI: 1.83 to 3.46, P < 0.001) or hip dysplasia (lateral center-edge angle (LCEA) <25°; OR = 2.38, 95% CI: 1.84 to 3.07, P < 0.001), but not hips with pincer morphology (LCEA >39°; OR = 1.08, 95% CI: 0.57 to 2.07, P = 0.810), were more likely to develop hip OA than hips without these morphologies. Cross-sectional studies showed a greater prevalence of pincer morphology (LCEA >39°, OR = 3.71, 95% CI: 2.98 to 4.61, P < 0.001) and acetabular retroversion (crossover sign; OR = 2.65, 95% CI: 1.17 to 6.03, P = 0.020) in hips with OA than in control hips.

CONCLUSION

Cam morphology and hip dysplasia were consistently associated with the development of hip OA. Pincer morphology was associated with hip OA in cross-sectional but not in prospective studies. The heterogeneous quantification of pincer morphology on radiographs limits a clear conclusion on its association with hip OA.

Multi-centre randomised controlled trial comparing arthroscopic hip surgery to physiotherapist-led care for femoroacetabular impingement (FAI) syndrome on hip cartilage metabolism: the Australian FASHIoN trial

Background

Arthroscopic surgery for femoroacetabular impingement syndrome (FAI) is known to lead to self-reported symptom improvement. In the context of surgical interventions with known contextual effects and no true sham comparator trials, it is important to ascertain outcomes that are less susceptible to placebo effects. The primary aim of this trial was to determine if study participants with FAI who have hip arthroscopy demonstrate greater improvements in delayed gadolinium-enhanced magnetic resonance imaging (MRI) of cartilage (dGEMRIC) index between baseline and 12 months, compared to participants who undergo physiotherapist-led management.

Methods

Multi-centre, pragmatic, two-arm superiority randomised controlled trial comparing physiotherapist-led management to hip arthroscopy for FAI. FAI participants were recruited from participating orthopaedic surgeons clinics, and randomly allocated to receive either physiotherapist-led conservative care or surgery. The surgical intervention was arthroscopic FAI surgery. The physiotherapist-led conservative management was an individualised physiotherapy program, named Personalised Hip Therapy (PHT). The primary outcome measure was change in dGEMRIC score between baseline and 12 months. Secondary outcomes included a range of patient-reported outcomes and structural measures relevant to FAI pathoanatomy and hip osteoarthritis development. Interventions were compared by intention-to-treat analysis.

Results

Ninety-nine participants were recruited, of mean age 33 years and 58% male. Primary outcome data were available for 53 participants (27 in surgical group, 26 in PHT). The adjusted group difference in change at 12 months in dGEMRIC was -59 ms (95%CI − 137.9 to - 19.6) (p = 0.14) favouring PHT. Hip-related quality of life (iHOT-33) showed improvements in both groups with the adjusted between-group difference at 12 months showing a statistically and clinically important improvement in arthroscopy of 14 units (95% CI 5.6 to 23.9) (p = 0.003).

Conclusion

The primary outcome of dGEMRIC showed no statistically significant difference between PHT and arthroscopic hip surgery at 12 months of follow-up. Patients treated with surgery reported greater benefits in symptoms at 12 months compared to PHT, but these benefits are not explained by better hip cartilage metabolism.

Trial registration details

Australia New Zealand Clinical Trials Registry reference: ACTRN12615001177549. Trial registered 2/11/2015.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-021-04576-z.

Primary cam morphology; bump, burden or bog-standard? A concept analysis

BACKGROUND

Cam morphology, a distinct bony morphology of the hip, is prevalent in many athletes, and a risk factor for hip-related pain and osteoarthritis. Secondary cam morphology, due to existing or previous hip disease (eg, Legg-Calve-Perthes disease), is well-described. Cam morphology not clearly associated with a disease is a challenging concept for clinicians, scientists and patients. We propose this morphology, which likely develops during skeletal maturation as a physiological response to load, should be referred to as primary cam morphology. The aim of this study was to introduce and clarify the concept of primary cam morphology.

DESIGN

We conducted a concept analysis of primary cam morphology using articles that reported risk factors associated with primary cam morphology; we excluded articles on secondary cam morphology. The concept analysis method is a rigorous eight-step process designed to clarify complex 'concepts'; the end product is a precise definition that supports the theoretical basis of the chosen concept.

RESULTS

We propose five defining attributes of primary cam morphology-tissue type, size, site, shape and ownership-in a new conceptual and operational definition. Primary cam morphology is a cartilage or bony prominence (bump) of varying size at the femoral head-neck junction, which changes the shape of the femoral head from spherical to aspherical. It often occurs in asymptomatic male athletes in both hips. The cartilage or bone alpha angle (calculated from radiographs, CT or MRI) is the most common method to measure cam morphology. We found inconsistent reporting of primary cam morphology taxonomy, terminology, and how the morphology is operationalised.

CONCLUSION

We introduce and clarify primary cam morphology, and propose a new conceptual and operational definition. Several elements of the concept of primary cam morphology remain unclear and contested. Experts need to agree on the new taxonomy, terminology and definition that better reflect the primary cam morphology landscape-a bog-standard bump in most athletic hips, and a possible hip disease burden in a selected few.

FAI morphology increases the risk for osteoarthritis in young people with a minimum follow-up of 25 years

INTRODUCTION

The mechanical conflict in symptomatic femoroacetabular impingement can lead to early osteoarthritis. However, radiographic impingement morphology is often seen in asymptomatic individuals. Long-term observation regarding the risk of developing osteoarthritis in these individuals is lacking. Our study addressed the following questions: Does femoroacetabular impingement morphology increase the risk for development of osteoarthritis after at least 25 years? If yes, which radiographic parameter is the most predictive? Does the level of activity influence the risk for development of osteoarthritis? Are PROM influenced by the grade of osteoarthritis in this population?

METHODS

We investigated 51 (32 male, 19 female) patients for whom AP pelvis and Dunn view radiographs were available with a minimum follow-up of 25 years. Alpha angle in AP pelvis and Dunn view radiographs, femoral torsion in Dunn view, lateral center edge angle, cross-over sign, posterior wall sign and prominence of ischial spine sign in AP pelvis radiographs were determined. On the follow-up radiographs, osteoarthritis was graded. Tegner Score for the time of the index radiograph was evaluated. Harris Hip Score and Western Ontario and McMaster Universities Osteoarthritis Index were assessed at latest follow-up.

RESULTS

The mean follow-up was 43 years (range 25-58). Cam impingement morphology showed to increase the risk for development of osteoarthritis: Alpha angles of ≥ 55° on AP pelvis and Dunn view radiographs were associated risk factors and showed an OR of 1.05 (p = 0.002) and 1.10 (p = 0.001), respectively. Abnormal femoral torsion and acetabular retroversion were not risk factors for osteoarthritis. Tegner Score at index presentation, HHS and WOMAC Score did not correlate with the grade of osteoarthritis.

CONCLUSION

This study showed that cam impingement morphology in young patients raises the risk for development of hip osteoarthritis by 5-10% in a long-term follow-up with a minimum of 25 years, thus its contribution was small.

Pre- and postoperative in silico biomechanics in individuals with cam morphology during stair tasks

BACKGROUND

Osteochondroplasty for cam femoroacetabular impingement is a common treatment to improve hip function and prevent joint degeneration. The purpose was to compare in-silico hip biomechanics during stair tasks in pre- and postoperative patients matched with healthy controls.

METHODS

Ten symptomatic cam femoroacetabular impingement patients performed stair ascent and descent pre- and 2 years postoperatively. Patients were age, and body-mass-index matched to controls. Full-body kinematics and kinetics were computed and, muscle and hip contact forces were estimated using musculoskeletal modeling and static optimization. Stance-phases were time-normalized and compared using statistical non-parametric mapping.

FINDINGS

Preoperatives showed lower hip abduction than controls during stairs ascent (76-100%, P = .007). Pre- and postoperative showed lower hip external rotation compared to controls on stair ascent (Pre-op vs controls: 71-100%, P = .005; Post-op vs controls: 72-100%, P = .01) and stair descent (Pre-op vs controls: 0-62%, P = .001; Post-op vs controls: 0-60%, P = .001). Postoperatives showed lower iliacus force compared to preoperative (1-3%, P = .012) and control (3-6%, P = .008), and higher gluteus maximus and piriformis forces compared to controls during stair descent. Lower postoperative anterior hip contact force (0-7%, P = .004) during descent, and superior (33-35%, P = .018) during ascent compared to controls were observed. Postoperative contact forces were medialized compared to preoperative (0-2%, P = .011) and controls (1-2%, P = .016).

INTERPRETATION

Forcing participants to adhere to standardized step length/rise minimized sagittal kinematic differences between conditions and groups. Persistent reduced hip external rotation postoperatively and minor muscle force adaptations led to reduced superior hip contact force during stair ascent and reduced anterior and more medialized contact forces during stair descent.

Low rate of adverse events in a randomized controlled trial addressing the surgical treatment of femoroacetabular impingement (FAI) syndrome

PURPOSE

The femoroacetabular impingement randomised controlled trial (FIRST) is a multi-center randomized controlled trial (RCT), comparing arthroscopic osteochondroplasty with arthroscopic lavage in adults aged 18-50 years diagnosed with non-arthritic femoroacetabular impingement (FAI) syndrome. The purpose of the present study is to report the prevalence, distribution and severity of adverse events during and within 24-month follow-up period.

METHODS

Of the 220 patients included, 6 were adjudicated as ineligible, for a total of 214 patients included in the final analysis. An independent Adjudication Committee evaluated operatively treated and non-operatively treated adverse events that were related to the hip. Adverse events were also reported directly by each participating clinical site. Continuous variables were reported as mean and standard deviation, categorical variables were reported as counts and percentages.

RESULTS

There were a total of 52 (24.2%, 52/214) adverse events in 46 (21.5%) patients (mean age 34.2 ± 7.9 years, 58.7% male) during the 24-month follow-up. There were 12.6% (27/214) operatively treated adverse events for: hip pain, re-injury of labrum and heterotopic ossification. There were 11.7% (25/214) non-operatively treated adverse events for predominantly: hip pain, hip tendinopathy and hip popping/snapping. Approximately, 87% of adverse events resolved within the 24-month follow-up time.

CONCLUSION

Given the inherent challenges with conducting RCTs, the results of this adverse event study from the FIRST trial demonstrate that it is safe to perform an RCT addressing FAI syndrome.

LEVEL OF EVIDENCE

Level III.

Comparison Between Hip Arthroscopic Surgery and Periacetabular Osteotomy for the Treatment of Patients With Borderline Developmental Dysplasia of the Hip: A Systematic Review

Background:

The treatment for borderline developmental dysplasia of the hip (BDDH) has historically been arthroscopic surgery or periacetabular osteotomy (PAO). As orthopaedic surgery is constantly evolving, a lack of comparison of outcomes for these 2 treatment methods could potentially be stalling the progression of treatment for patients with BDDH.

Purpose:

To evaluate the existing literature on patient characteristics, procedures, clinical outcomes, and failure rates for patients with BDDH and to determine whether PAO or hip arthroscopic surgery is a better treatment method for patients with BDDH.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

Studies included were found using the following search words: “hip” and “borderline dysplasia,” “osteotomy” or “arthroscopy,” and “outcome” or “procedure.” Articles were included if they detailed participants of all sexes and ages, reported on isolated hips, and had patients diagnosed with BDDH.

Results:

A search was conducted across 3 databases, resulting in 469 articles for consideration, from which 12 total studies (10 on arthroscopic surgery and 2 on PAO) were chosen for a review. There were 6 studies that included patients with a lateral center-edge angle of 18° to 25°, while the remainder included patients with a lateral center-edge angle of 20° to 25°. All the studies reviewing arthroscopic surgery reported concomitant/accessory procedures, while the articles on the topic of PAO did not. It was determined that, whether treated using arthroscopic surgery or PAO, outcomes improved across all patient-reported outcome measures. Revision surgery was also common in both procedures.

Conclusion:

There is a lack of consensus in the literature on the best treatment option for patients with BDDH. Preoperative patient characteristics and concomitant injuries should be considered when evaluating which surgical procedure will result in the most favorable outcomes.