Association of Cam Deformity on Anteroposterior Pelvic Radiographs and More Severe Chondral Damage in Femoroacetabular Impingement Syndrome

Associations between hip cartilage lesions and morphologic parameters of bony structures in a cohort of Asian patients with labral tears measured using a computed tomography-based software system

OBJECTIVE

This study aimed to investigate the associations between hip cartilage lesions and bony morphologic parameters in the hip joints using a computed tomography-based software system.

METHODS

Seventy-nine symptomatic hips that underwent hip arthroscopic labral preservation surgery were enrolled in this study. Bony structural morphologic parameters were subsequently assessed via a computed tomography-based software system. The indices included the femoral neck anteversion (FNA), alpha angle (AA) at each o'clock position of the femoral head, lateral center-edge angle (LCEA), and three-dimensional acetabular coverage (3D-AC). Cartilage damage was confirmed arthroscopically and classified according to the Multicenter Arthroscopy of the Hip Outcome Research Network (MAHORN) classification as well as the International Cartilage Repair Society classification.

RESULTS

Of the 79 hips, 41 patients were male, and 38 were female, with a mean age of 39.1 years ​±16.1 years (11-78). The mean LCEA was 27.6° ​± ​8.6° (range 7°-46°), and the mean FNA was 22.9° ​± ​14.4° (range -2°-63°). Grade 4 or 5 MAHORN acetabulum cartilage lesions were observed in 10 hips (13 ​%), while femoral head cartilage lesions with ICRS grade of 3 or 4 were found in 10 hips. Patients with MAHORN grade 4 or 5 cartilage lesions had significantly greater FNA compared with those with MAHORN grade 0 to 3 lesions (32.6° ​± ​10.3° versus 21.4° ​± ​14.4°, p ​= ​0.009). Although patients with MAHORN grade 4 or 5 lesions had greater AA at the entire o'clock of the femoral neck, the difference was not statistically significant. Patients whose FNAs were 26° or larger had a 6.2-fold greater odds ratio (95 ​% confidence interval, 1.2-31.5) of acetabular cartilage damage than those whose FNAs were less than 26° (p ​= ​0.015).

CONCLUSION

The use of computed tomography-based software provided detailed insights into bony abnormalities reinforcing its utility in evaluating hip joint pathologies and their relationship with cartilage lesions.

LEVEL OF EVIDENCE

Level III.

Predictive importance of cartilage acetabular index for acetabular dysplasia in orthopedic surgery

PURPOSE

To investigate the relationship between the cartilage acetabular index and acetabular development and secondary dysplasia.

METHODS

A total of 58 hips underwent intraoperative arthrography-guided open reduction or limited open reduction due to developmental hip dysplasia between 2011 and 2015 was included in the study. We evaluated patients with acetabular angle 8º as group 2. Intraoperative acetabular cartilage index measurements were performed, and patients with low and high cartilage acetabular index were divided into two groups.

RESULTS

There was a correlation between the cartilage acetabular index value, which indicates preoperative cartilage acetabular coverage, and acetabular development and secondary acetabular development.

CONCLUSION

The cartilage acetabular index is a technically easy and uncomplicated evaluation method that can be used to estimate acetabular development and should be used routinely together with the bone acetabular index.

Patients With Lateral and Anterolateral Cam Morphology Have Greater Deformities Versus Typical Anterolateral Deformity Alone but No Differences in Postoperative Outcomes: A Propensity-Matched Analysis at Minimum 5-Year Follow-Up

PURPOSE

To compare pre- and postoperative findings between patients undergoing hip arthroscopy for femoroacetabular impingement syndrome with lateral impingement versus those without lateral impingement METHODS: Patients who underwent primary hip arthroscopy for femoroacetabular impingement syndrome between 2012 and 2017 with minimum 5-year follow-up were included. Alpha angle (AA) was measured on preoperative anteroposterior (AP) and 90° Dunn radiographs. Patients with AA >60° on Dunn view but not AP view (no lateral impingement) were propensity matched by sex, age, and body mass index in a 1:3 ratio to patients with AA >60° on both views (lateral impingement). Demographic characteristics, radiographic and intraoperative findings, reoperation rates, and patient-reported outcomes (PROs) were compared between groups. Categorical variables were compared using the Fisher exact testing and continuous variable using 2-tailed Student t tests.

RESULTS

Sixty patients with lateral impingement (65.0% female, age: 35.3 ± 13.0 years) were matched to 180 patients without lateral impingement (65.0% female, age: 34.7 ± 12.5 years, P ≥ .279). Patients with lateral impingement had larger preoperative AAs on both Dunn (71.0° ± 8.8° vs 67.6° ± 6.1°, P = .001) and AP radiographs (79.0° ± 12.1° vs 48.2° ± 6.5°, P < .001). However, there were no differences in postoperative AAs on either view (Dunn: 39.0° ± 6.1° vs 40.5° ± 5.3°, AP: 45.8° ± 9.0° vs 44.9° ± 7.0°, P ≥ .074). Labral tears began more superiorly in patients with lateral impingement (12:00 ± 0:49 vs 12:17 ± 0:41, P = .030), and they demonstrated greater rates of acetabular and femoral cartilage damage (P = .030 for both); however, there were no differences in PROs or reoperation rates between the groups at 5-year follow-up.

CONCLUSIONS

Although cam deformities located laterally and anterolaterally are larger than those located anterolaterally alone, both can be resected adequately, resulting in similar postoperative radiographic measurements, PROs, and survivorship.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Current understanding of articular cartilage lesions in femoroacetabular impingement syndrome

The concept of femoroacetabular impingement syndrome (FAIS) has received much attention over the past 20 years. Currently, it is believed that FAIS can lead to intra-articular pathologies such as labral tears and articular cartilage lesions, resulting in clinical symptoms and subsequent poor clinical outcomes. FAIS-related articular cartilage lesions are common but unique, and their natural course always leads to early osteoarthritis of the hip. However, despite these cartilage lesions having gradually gained considerable attention, limited consensus has been reached on key aspects, such as diagnosis, mechanisms, classification, and management strategies, which limits clinical and research advances. Hence, an intensive comprehensive overview based on the existing evidence is necessary. The purpose of this review was to introduce the general consensus, controversial issues, and recent advances in FAIS-related articular cartilage lesions.

The association between cam morphology and hip pain in males and females within 10 years: A national prospective cohort study (CHECK)

OBJECTIVES

To determine the association between baseline cam morphology and self-reported hip pain assessed at annual visits over a 10-year follow-up period stratified by biological sex. The secondary aim was to study the association between the magnitude of cam morphology and the severity of pain in symptomatic hips.

METHODS

The nationwide prospective Cohort Hip and Cohort Knee (CHECK) study includes 1,002 participants aged 45-65 years. Logistic regression with generalized estimating equations were used to determine the strength of the associations between (1) baseline cam morphology (both alpha angle ≥60° and as a continuous measure) and the presence of hip pain at 10 annual follow-up visits and (2) the alpha angle (continuous) and the severity of pain as classified by Numerical Rating Scale at 5-,8-, 9-, and 10-years. The results are expressed as odds ratios (OR), adjusted for age, biological sex (only in the sex-combined group), body mass index, and follow-up Kellgren and Lawrence grade.

RESULTS

In total, 1,658 hips were included at baseline (1,335 female hips (79.2%)). The prevalence of cam morphology was 11.1% among all hips (29.1% in males; 6.4% in females). No association was found between cam morphology at baseline and the presence of hip pain at any follow-up in the female or sex-combined group. In males, only at 5-year follow-up, significant adjusted ORs were observed for the presence of cam morphology (1.77 (95%CI: 1.01-3.09)) and the alpha angle (1.02 (95%CI:1.00-1.04)). No evidence of associations was found between the alpha angle and the severity of hip pain in any of three groups.

CONCLUSION

Within this study, no consistent associations were found between cam morphology and hip pain at multiple follow-ups. There might be a weak relationship between cam morphology and hip pain in males, while no such relation was found in females. We did not identify an association between the alpha angle and severity of hip pain.

Femurs in patients with hip dysplasia have fundamental shape differences compared with cam femoroacetabular impingement

Femoral deformities are common in developmental dysplasia of the hip (DDH), but decisions about how to treat them are not standardized. Of interest are deformities that may be akin to cam femoroacetabular impingement (FAI). We used three-dimensional and two-dimensional measures to clarify the similarities and differences in proximal femur shape variation among female patients with DDH (n = 68) or cam FAI (n = 60). Three-dimensional measures included femoral head asphericity, as well as shape variation using statistical shape modeling and principal component analysis (PCA). Two-dimensional measures included the α-angle, head-neck offset (HNO) and the neck-shaft angle (NSA). Significant shape variations were captured in the first five PCA modes, with the greatest shared variation between groups being the length from the lesser trochanter to the femoral head and greater trochanter height. Variations unique to DDH were irregularities at different areas of the femoral head, but not at the lateral femoral head-neck junction where variation was strong in FAI. The FAI group also had unique variations in greater trochanter shape. DDH femoral heads were less spherical, as indicated by larger sphere-fitting errors (P < 0.001). Radiographically, the DDH group had significantly smaller α-angles (P < 0.001), larger head-neck offsets (P = 0.02) and larger NSAs (P < 0.001). Both the articular and extra-articular regions of the proximal femur have distinct shape features in DDH and cam FAI that can uniquely affect the biomechanics of each disorder. Accordingly, approaches to addressing each disorder should be unique.

A Superolateral Cam Lesion Location Increases Odds of Total Hip Arthroplasty 5 Years After Hip Arthroscopy

PURPOSE

To determine if radiographic cam location is associated with hip survivorship and postoperative patient-reported outcomes (PROs) at 5-year follow-up.

METHODS

We conducted a review of prospectively collected data of patients with cam lesions who underwent hip arthroscopy for femoroacetabular impingement syndrome. Cam lesions were categorized into 3 locations: superolateral, anterolateral, or anterior. Conversion to total hip arthroplasty (THA), revision rates, and reoperation rates were assessed. Patient-reported outcome measures, including modified Harris Hip Scores (mHHS) and Non-Arthritic Hip Scores (NAHS), were collected preoperatively and at 5-year follow-up.

RESULTS

Of the 156-patients, 125 met the final criteria (80.1%). Mean age was 41.1 ± 12.7 years. Seventy-one patients (56.8%) had superolateral cam lesions, 41 (32.8%) had anterolateral lesions, and 13 (10.4%) had anterior lesions. Revision rates within 5 years were 7.7% for anterior, 24.4% for anterolateral, and 14.1% for superolateral lesions; conversions to THAs were 15.4% for anterior), 7.3% for anterolateral, and 8.5% for superolateral. Reoperations were 23.1% for anterior, 29.3% for anterolateral, and 21.1% for superolateral. The superolateral cohort was younger than the anterior and anterolateral cohorts (anterior, 46.6 ± 12.2 years; anterolateral, 44.7 ± 12.2 years; superolateral, 38.1 ± 12.3 years; P = .006). Multivariable analysis showed the anterolateral group was significantly predictive of lower odds of undergoing THA compared to the superolateral group (odds ratio, 0.01; 95% CI, <0.01-0.72; P = .03). There were no differences in the 5-year improvement in mHHS (anterior, 32.4; anterolateral, 36.8; superolateral, 33.0; P = .29) or NAHS (anterior, 34.8; anterolateral, 39.0; superolateral, 37.3; P = .65).

CONCLUSIONS

A superolateral cam lesion increases the odds of conversion to THA within 5 years of hip arthroscopy compared to those with anterolateral lesions on multivariable analysis. Those with superolateral lesions were significantly younger compared to those with anterior or anterolateral lesions. Cam lesion location did not affect improvement in PROs at 5-year follow-up.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

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.