Use of Younger Patient Age and Greater Anterior Center-Edge Angle to Predict the Need for Bilateral Hip Arthroscopy in Patients With Bilateral Femoroacetabular Impingement-Related Hip Pain

Primary and Revision Hip Arthroscopy in Borderline Hip Dysplasia Shows Comparable Outcomes at a Minimum 5-Year Follow-Up

PURPOSE

To compare patient-reported outcomes (PROs), achievement of clinically significant outcomes, and reoperation-free survivorship between primary and revision hip arthroscopy (HA) for femoroacetabular impingement syndrome (FAIS) in propensity-matched borderline hip dysplasia (BHD) patients at a minimum 5-year follow-up.

METHODS

Patients with BHD, characterized by a lateral center-edge angle 18° to 25°, who underwent HA for FAIS with capsular repair by a single surgeon between January 2012 and June 2018 with a minimum 5-year follow-up were identified. Cases of revision HA were propensity-matched 1:2 to cases of primary HA, controlling for age, sex, and body mass index. A 1:2 ratio was chosen to maximize the number of included patients. Collected PROs included Hip Outcome Score-Activities of Daily Living and Sport Subscales, International Hip Outcome Score 12, modified Harris Hip Score, and Visual Analog Scale for Pain. Achievement of minimal clinically important difference, patient acceptable symptom state, and substantial clinical benefit for any measured PRO was compared between groups along with reoperation-free survivorship using Kaplan-Meier analysis.

RESULTS

Thirty-six revision HA hips (34 patients) were propensity-matched to 72 primary HA hips (70 patients). The groups were similar in age (31.5 ± 10.3 years vs 30.5 ± 11.2, P = .669), sex (69.4% female vs 70.8%, P = .656), and body mass index (25.7 ± 4.0 vs 25.5 ± 3.7, P = .849). The revision group showed a greater prevalence of prolonged preoperative pain (50.0% vs 27.8%, P = .032) compared with the primary group. A significant improvement in all PROs was observed for both groups with comparable PROs preoperatively and at the 5-year follow-up between groups (P ≥ .086). The revision and primary groups showed comparable minimal clinically important difference (95.0% vs 95.7%, P ≥ .999), patient acceptable symptom state (80.0% vs 83.6%, P = .757), and substantial clinical benefit (62.5% vs 70.7%, P = .603) achievement for any PRO. Comparable reoperation-free survivorship was observed (P = .151).

CONCLUSIONS

Propensity-matched patients with BHD undergoing primary and revision hip arthroscopy for FAIS achieved similar minimum 5-year PROs, clinically significant outcomes, and reoperation-free survivorship.

LEVEL OF EVIDENCE

Level III, retrospective comparative case series.

Staged Bilateral Hip Arthroscopy for Femoroacetabular Impingement Syndrome: Index Surgery Patient Reported Outcome Measures Predict Contralateral Surgery Results at 2 Years

PURPOSE

To determine whether (1) patient-reported outcome (PRO) scores after index hip arthroscopy correlate with PRO scores for the contralateral hip in patients undergoing staged bilateral hip arthroscopy and (2) patients who achieved minimal clinically important difference (MCID) or patient-acceptable symptom state (PASS) for the index hip were more likely to achieve MCID or PASS for the contralateral hip.

METHODS

Patients who underwent staged bilateral hip arthroscopy for femoroacetabular impingement syndrome were retrospectively reviewed. PRO scores were prospectively collected at preoperative and 1- and 2-year timepoints. Odds ratios for achievement of MCID and PASS for the contralateral hip given achievement for the index hip were calculated. Improvements from before surgery to 2 years after surgery were correlated between both hips.

RESULTS

A total of 143 patients (286 hips) were included in the final analysis. Average time between surgeries was 8.5 months (range, 0.7-57.2). Both hips demonstrated significant improvement (P < .05 for all) in all PROs at 2 years. Achievement of MCID in Hip Outcome Score Activities of Daily Living (HOS-ADL) at the 1-year timepoint for the index hip was predictive of achievement of MCID in HOS-ADL at 2 years for the contralateral hip. Achievement of PASS in all PROs at the 1-year timepoint for the index hip were predictive of achievement of PASS in the equivalent outcome score at the 2-year mark for the contralateral hip. Achievement of MCID or PASS at the 2-year timepoint for the index hip was predictive of achievement of the equivalent outcome at the 2-year timepoint for the contralateral hip. The strongest correlation between improvement in PRO scores for the index and contralateral hips was noted in patients who underwent staged hip arthroscopy within less than 3 months.

CONCLUSION

Patients experience significant clinical benefit in both hips after staged bilateral hip arthroscopy. Results from the initial hip arthroscopy at either 1- or 2-year follow-up can be used to predict outcomes on the contralateral side; however, there is a higher degree of predictive value using 2-year results. Average correlations between 2-year PROs on the index and contralateral hips were moderate to strong, regardless of the time between surgeries.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Assessment of Femoral Torsion on Magnetic Resonance Imaging is More Reliable Using Axial-Oblique Sequences Compared With Standard Axial Slices in Patients With Femoroacetabular Impingement Syndrome

PURPOSE

To determine the agreeability of femoral torsion measurements on axial and oblique axial magnetic resonance imaging (MRI) sequences in patients with femoroacetabular impingement syndrome (FAIS).

METHODS

Patients who underwent primary hip arthroscopy for FAIS between January 2012 to January 2019 were identified. Inclusion criteria were all patients with an MRI scan containing the pelvis and knee imaging. MRI-based measurements of femoral torsion were performed on axial and oblique-axial slices by 2 raters, and inter-rater and intrarater reliability was assessed. Bland Altman plots were constructed to evaluate the agreeability between femoral torsion measurements performed using axial and oblique-axial slices. Bivariate correlation analyses were performed to assess the relationship between measurement methods on each respective scan. A linear regression was performed between measurements performed using axial and oblique-axial sequences.

RESULTS

A total of 164 patients were included. The mean true-axial and oblique axial femoral torsion were 12.2° ± 9.9° and 11.1° ± 9.2°, respectively. The intrarater reliability for axial and oblique-axial measurements were 0.993 and 0.997, respectively. The inter-rater reliability for axial and oblique-axial measurements were 0.925 and 0.965, respectively. The number of differences within the limits of agreement for axial and oblique-axial femoral torsion measurements was 58.54%. On Pearson correlation analysis, strong positive correlations were found between oblique-axial measurements at multiple time points (r = 0.994, P < .001), as well as axial measurements at multiple time points (r = 0.986, P < .001). A strong positive correlation was found between axial and oblique-axial measurements (r = 0.894, P < .001). A significant regression equation indicated that for each additional increase in axial femoral torsion, the oblique-axial femoral torsion increased 0.837 (95% confidence interval 0.772-0.901).

CONCLUSIONS

Femoral torsion values measured on oblique-axial sequences are smaller than on true-axial sequences. Femoral torsion measurements on axial and oblique-axial MRI sequences exhibit poor agreement. Oblique-axial sequences demonstrated greater measurement consistency at multiple timepoints. When evaluating torsional measurements, it is important to delineate which axial sequence was used, especially in patients with suspected severe femoral antetorsion. Standardization of MRI femoral version protocols within one's practice can ensure more consistent decision-making, especially in patients with suspected femoral antetorsion.

LEVEL OF EVIDENCE

Retrospective cohort, level III.