Subspine Impingement Research Articles

ARTHROSCOPIC TREATMENT OF ANTERIOR INFERIOR ILIAC SPINE IMPINGEMENT: FIVE-YEAR CLINICAL OUTCOMES

There is a limited literature available describing the various diagnostic modalities and treatment options for the management of subspine impingement (SSI). We developed a study to evaluate the clinical improvement at 1 year and 5 years, with iHOT 33 and HOS hip scores.(1) Do patients with subspine compression improve with arthroscopic treatment clinically at short term follow-up (1 year)? (2) Is the improvement maintained in the mid-term (5 years)?43 young patients with subspine compression (prominent anterior inferior iliac spine) treated arthroscopically between January 2010 and December 2021 were included. Patients completed the iHOT33, HOS-SPORT and HOS-ADL questionnaires before surgery, 1 year and 5 years follow up. We evaluated pre and postoperative differences at one year and at 5 years. Minimum Clinically Significant Difference (MCID) and the Substantial Clinical Benefit (SCB) were used to stablish clinical improvement.Mean age was 37.38 years and 66% were males. Almost 75% and 70% of our patients exceed the MCID and the SCB respectively in all the questionnaires after 1 year-follow up. However, at 5 years-follow up, nearly 70% and 65% of the patients exceeded MCID and SCB respectively.We demonstrate that arthroscopic treatment of subspine impingement as an effective treatment for Subspine impingement. However, it is necessary larger sample size and longer follow up period to analyze the long-term results to demonstrate this treatment as the “gold standard”.

Defining the Percent Thresholds for Achieving the Maximum Outcome Improvement of the Modified Harris Hip Score, the Non-Arthritic Hip Score, the Hip Outcome Score-Sports Subscale, the Visual Analog Scale for Pain, and the International Hip Outcome Tool-12 in Revision Hip Arthroscopy at Minimum 2-Year Follow-Up

To determine the respective percent thresholds for achieving the maximal outcome improvement (MOI) for the modified Harris Hip Score (mHHS), the Non-Arthritic Hip Score (NAHS), the Hip Outcome Score-Sports Subscale (HOS-SSS), the visual analog scale (VAS) for pain, and the International Hip Outcome Tool-12 (iHOT-12) that were associated with satisfaction following revision hip arthroscopy, and to identify predictors for achieving the MOI. An anchor question was provided to patients who underwent revision hip arthroscopy between April 2017 and July 2020. Patients were included for the final analysis if they answered the anchor question and had minimum 2-year follow-up. Receiver operating characteristic analysis was used to determine the thresholds for the percentage of the MOI predictive of satisfaction. A P-value of < .05 was considered significant. In total, 318 patients underwent revision hip arthroscopy. Of those patients, 292 (91.8%) had minimum 2-year follow-up. Of this cohort, 68 answered the anchor question, with 49 (72.1%) female and 19 (27.9%) male patients. The mean age, and body mass index time were 32.9 ± 13 years and 25.4 ± 5.1, respectively. It was determined that 42.1%, 50%, 48.1%, 50%, and 50% of MOI were the thresholds for maximal predictability of satisfaction for mHHS, NAHS, HOS-SS, VAS for pain, and the iHOT-12, respectively. The presence of unaddressed subspine impingement was a significant predictor for achieving the MOI threshold for the VAS (odds ratio 1.40; 95% confidence interval 1.00-1.95; P= 0.0273). Following revision hip arthroscopy, the percent thresholds for achieving the MOI at a minimum 2-year follow-up for the mHHS, NAHS, HOS-SS, VAS for pain, and iHOT-12 were 42.1%, 50%, 48.1%, 50%, and 50.9%, respectively. Addressing residual subspine impingement was identified as significant positive predictor for achieving the MOI. Level IV, case-series.

Poster 232: Clinical Outcomes Among Individuals with Global Acetabular Retroversion who Underwent Hip Arthroscopy for FAI with Minimum 5-Year Follow-Up

Objectives: The purpose of this study was to compare functional outcomes and clinical threshold achievement rates of patients with radiographic signs of global acetabular retroversion who underwent hip arthroscopy for FAI with minimum follow-up of 5 years. Methods: Patients were identified from a single-surgeon prospectively-collected database who underwent primary hip arthroscopy for treatment of FAI. Patients completed patient-reported outcome (PRO) surveys at both baseline and at 5-year follow-up. Demographic data was collected including age, sex, BMI at time of surgery, and patient-reported symptom length. Intraoperative findings were recorded, including the Outerbridge grade, presence of labral tears, chondral delamination, subspine impingement, cam lesions, pincer lesions, and mixed-type FAI. Global acetabular retroversion was assessed on AP view using three radiographic signs: ischial spine, posterior wall, and crossover signs. Other radiographic measures included alpha angle measured on three view (AP, 45° Dunn, 90° Dunn), lateral center edge angle (LCEA), and Tönnis grade. Results: We identified 124 primary hip arthroscopy patients who had minimum 5-year follow-up with adequate imaging and complete 5-year PROs. Preoperative X-rays demonstrated presence of ischial spine sign in 65 patients (52.4%), posterior wall sign in 61 patients (49.2%), and crossover sign in 75 patients (60.5%). Mean alpha angle was highest on AP view (62.2°), followed by 45° Dunn view (55.9°) and 90° Dunn view (50.9°) and mean LCEA was 38.5°. A baseline comparison demonstrated no significant differences between groups in age, sex, BMI, preoperative symptom length, Tönnis grade, Outerbridge grade, and preoperative mHHS or NAHS (p&gt;0.05). At 5-year follow-up, patients reported significant improvement in both mHHS (mean 50.4 to 82.7, p&lt;0.001) and NAHS (49.4 to 85.5, p&lt;0.001). Achievement rates were high for MCID (90.3%), SCB (80.7%), and PASS (79.0%) for the mHHS. Three-way frequency comparison of acetabular retroversion signs found that all three signs tended to be present together (40 patients, 32.3%) or absent together (31 patients, 25.0%). Pairwise comparisons with tetrachoric correlation testing found all three signs to be significantly correlated with one another: ischial spine sign versus posterior wall (rtet=0.65, corrected p&lt;0.001), ischial spine sign versus crossover sign (rtet=0.74, corrected p&lt;0.001), and posterior wall sign versus crossover sign (rtet=0.51, corrected p&lt;0.001). Multivariable analysis did not find any of the three signs to be significant independent predictors of 5-year improvement in mHHS or NAHS (p&gt;0.05). Posterior wall sign was associated with lower odds of achieving the MCID (OR = 0.62, 95% CI [0.06 to 1.09]) but this did not achieve significance (χ2=3.39, p=0.07). Overall, achievement rates for MCID, SCB, and PASS did not significantly differ between the cohorts with respect to each sign (p&gt;0.05). Conclusions: Clinical outcomes and achievement rates at 5-year follow-up demonstrated no significant differences among patients with respect to each sign of acetabular retroversion based on mHHS, NAHS, MCID, SCB and PASS. Surgeons should be reassured that these patients regain function at a rate similar to the greater FAI population.

Ultrasound Assessment of Hip Subspine Bone Morphology Soft-tissue Correlates with Clinical Diagnosis of Impingement

To determine the ultrasound imaging manifestations associated with subspine impingement (SSI), including the osseous and soft-tissue injuries adjacent to anterior inferior iliac spine (AIIS) and to investigate the diagnostic value of ultrasound for SSI. We retrospectively evaluated patients who attended the sports medicine department of our hospital and underwent arthroscopic treatment for femoroacetabular impingement (FAI) between September 2019 and October 2020, with preoperative hip joint ultrasound and computed tomography (CT) examination within 1 month before surgery. All of the FAI patients were divided into the SSI group and non-SSI group, according to the clinical and intraoperative findings. The preoperative ultrasound and CT findings were assessed. The sensitivity, specificity, and positive predictive value (PPV) of some indicators were calculated and compared. Multivariable logistic regression and receiver operating characteristic curve (ROC) were also used. A total of 71 hips were included, with a mean age of 35.4 ± 10.4 years, 56.3% were women. Of these, 40 hips had clinically confirmed SSI. The bone morphology type III, heterogeneous hypoecho in anterosuperior joint capsule and the direct head of rectus femoris (dRF) tendon adjacent to AIIS on the Standard Section of the dRF in ultrasound were associated with SSI. Among them, the heterogeneous hypoecho in the anterosuperior joint capsule had the best diagnostic value for the SSI (85.0% sensitivity, 58.1% specificity, AUC= 0.681). The AUC of the ultrasound composite indicators was 0.750. The AUC and PPV of CT low-lying AIIS for the SSI diagnosis was 0.733 and 71.7%, which could be improved when CT was combined with the ultrasound composite indicators with AUC= 0.831 and PPV= 85.7%. Bone morphology abnormalities and soft-tissue injuries adjacent to the AIIS through sonographic evaluation were associated with SSI. Ultrasound could be used as a feasible method to predict SSI. The diagnostic value for SSI could be improved when ultrasound is combined with CT. Level IV, case series.

Arthroscopic Decompression of the Anterior Inferior Iliac Spine.

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. 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. 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. 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. 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. 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. 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.

Large Hip Impingement Area and Subspine Hip Impingement in Patients With Absolute Femoral Retroversion or Decreased Combined Version.

It remains unclear if femoral retroversion is a contraindication for hip arthroscopy in patients with femoroacetabular impingement (FAI). To compare the area and location of hip impingement at maximal flexion and during the FADIR test (flexion, adduction, internal rotation) in FAI hips with femoral retroversion, hips with decreased combined version, and asymptomatic controls. Cross-sectional study; Level of evidence, 3. Twenty-four symptomatic patients (37 hips) with anterior FAI were evaluated. All patients had femoral version (FV) <5° according to the Murphy method. Two subgroups were analyzed: 13 hips with absolute femoral retroversion (FV <0°) and 29 hips with decreased combined version (McKibbin index <20°). All patients were symptomatic and had anterior groin pain and a positive anterior impingement test ; all had undergone pelvic computed tomography (CT) scans to measure FV. The asymptomatic control group consisted of 26 hips. Dynamic impingement simulation of maximal flexion and FADIR test at 90° of flexion was performed with patient-specific CT-based 3-dimensional models. Extra- or intra-articular hip impingement area and location were compared between the subgroups and with control hips using nonparametric tests. Impingement area was significantly larger for hips with decreased combined version (<20°) versus combined version (≥20°) (mean ± SD; 171 ± 140 vs 78 ± 55 mm2; P = .012) and was significantly larger for hips with FV <0° (absolute femoral retroversion) vs FV >0° (P = .025). Hips with absolute femoral retroversion had a significantly higher frequency of extra-articular subspine impingement versus controls (92% vs 0%; P < .001), compared to 84% of patients with decreased combined version. Intra-articular femoral impingement location was most often (95%) anterosuperior and anterior (2-3 o'clock). Anteroinferior femoral impingement location was significantly different at maximal flexion (anteroinferior [4-5 o'clock]) versus the FADIR test (anterosuperior and anterior [2-3 o'clock]) (P < .001). Patients with absolute femoral retroversion (FV <0°) had a larger hip impingement area, and most exhibited extra-articular subspine impingement. Preoperative FV assessment with advanced imaging (CT/magnetic resonance imaging) could help to identify these patients (without 3-dimensional modeling). Femoral impingement was located anteroinferiorly at maximal flexion and anterosuperiorly and anteriorly during the FADIR test.

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

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

A comparison between ultrasound-guided AIIS injection and radiography in the diagnosis of subspine impingement in patients with FAI

BackgroundSubspine impingement (SSI) does not have effective diagnostic criteria, especially in patients who also have femoroacetabular impingement (FAI). The classification of anterior inferior iliac spine (AIIS) morphology via three-dimensional CT is controversial.PurposeTo propose a method for ultrasound-guided AIIS injection as a way to diagnose SSI and evaluate the accuracy of radiography methods, including 3-D CT and MRI, as well as intraoperative findings.MethodsPatients diagnosed with FAI between September 2020 and December 2021 were evaluated in this prospective study. Those who met the criteria were included in the ultrasound-guided AIIS injection test. Whether the pain was relieved after injection was recorded in the radiology report. Patients who experienced significant relief of the anterior groin pain (more than 50%) after the AIIS injection were considered positive responders. Among these patients, radiography materials, including AIIS morphology as measured by 3-D CT as well as superior capsular oedema on MRI, were compared. The presence of congestion or bruising on the capsule side of the labrum corresponding to the AIIS during hip arthroscopy was recorded.ResultsA total of 73 patients with FAI underwent the ultrasound-guided AIIS injection test. Prevalence rates of 13.70% (10/73), 58.90% (43/73), 23.29% (17/73) and 4.11% (3/73) were recorded for Type I, Type IIA, Type IIB and Type III AIISs, respectively. Thirty-six patients had positive responses to injection, and 37 patients had negative responses to injection. None of the patients with Type I, 23 (53.49%) patients with Type IIA, 11 (64.71%) patients with Type IIB and 2 (66.7%) patients with Type III AIISs had positive responses to the injection. A total of 57.14% of patients with Type II or Type III AIIS had positive responses to the injection. The proportions of patients with superior capsular oedema on MRI in the Type I, Type IIA, Type IIB, and Type III AIIS groups was 0, 30.23, 29.41 and 0%, respectively. Among non-Type I AIIS patients, those who reported positive responses to the injection had a higher incidence of superior capsular oedema (38.89% vs. 14.81%, P = 0.036), but they had no significant differences in the proportion of congestion or bruising of the labrum (47.22% vs. 37.04%, P = 0.419). The results showed that no pairs of methods—ultrasound-guided injection, MRI, and intraoperative findings—achieved good consistency (κ = 0.222, κ = 0.098 and κ = − 0.116).ConclusionsRadiographic methods including 3-D CT and MRI as well as the intraoperative findings of the labrum cannot be considered an accurate and reliable basis for the diagnosis and treatment of SSI in FAI patients. It is suggested that ultrasound-guided AIIS injections be combined with radiography to better diagnose SSI.Level of EvidenceIV, case series.

The narrow subspine space and relatively large labrum are radiographic features of subspine impingement: a case-control study

BackgroundSubspine impingement is considered a source of residual hip symptoms after primary hip arthroscopy, and the role of the subspine space and soft tissue is not clear. The purpose of this study was to analyze the relationship between the subspine space and labrum size in subspine impingement patients.MethodsWe performed a retrospective study of patients with femoroacetabular impingement between July 2016 and July 2020. Sixteen patients without hip symptom relief after primary hip arthroscopic treatment of femoroacetabular impingement and undergoing revision surgery for anterior inferior iliac spine compression were included as the study group. Forty-eight matched patients who underwent only primary surgery and whose hip discomfort was relieved without a diagnosis of subspine impingement were included as the control group. The patients’ preoperative computerized tomography data were reviewed, and the anterior inferior iliac spine dimensions and the size of the subspine space were measured. The size of the labrum at the 11:30, 1:30, and 3 o’clock positions was measured with the use of magnetic resonance imaging. The ratio of the subspine space to the labrum was also calculated.ResultsThere was no significant difference in anterior inferior iliac spine dimensions between these two groups (p > 0.05). A relatively narrow subspine space was found in the study group, especially in the direction of the anterior inferior iliac spine. Compared with the control group, subspine impingement patients were identified with larger labrums at 11:30 (8.20 ± 1.95 mm vs. 6.81 ± 0.50 mm, p = 0.016), 1:30 (7.83 ± 1.61 mm and 6.25 ± 0.78 mm, p = 0.001) and 3:00 (9.50 ± 1.73 mm vs. 7.48 ± 0.99 mm, p = 0.001). A relative mismatch between the subspine space and the labrum was also identified in the study group. The ratios of the labrum width to the subspine area were significantly larger in the study group than in the control group.ConclusionThis study reported potential additional criteria for subspine impingement—a large labrum and a relatively narrow subspine space—instead of abnormal anterior inferior iliac spine dimensions. For those with a large labrum and narrow subspine space, the diagnosis of subspine impingement should be carefully made, and arthroscopic anterior inferior iliac spine decompression may be important.

Imaging Diagnosis, Prevalence, and Clinical Outcomes of Arthroscopic Surgery for Anterior Inferior Iliac Spine Impingement: A Systematic Review and Meta-analysis.

Subspine impingement, or anterior inferior iliac spine (AIIS) impingement, is a type of extra-articular pathology associated with femoroacetabular impingement syndrome and often requires subsequent arthroscopic surgery. To examine the diagnostic accuracy, prevalence, and clinical outcomes of arthroscopic treatment for AIIS impingement. Systematic review; Level of evidence, 4. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 checklist was applied. We searched for studies on the prevalence, diagnostic accuracy, and results of surgical treatment for AIIS impingement. For each included study, data synthesis and statistical analysis were performed to identify pooled prevalence, calculate clinical outcome scores, and estimate adverse events. The QUADAS (a quality assessment tool for diagnostic accuracy studies) was used to assess the quality of the diagnostic accuracy studies, and the Risk of Bias Assessment tool for Nonrandomized Studies was used to assess the quality of the studies on arthroscopic treatment efficacy. Out of an initial 791 studies, 23 were included. AIIS impingement was diagnosed by plain radiography with 76% to 86% sensitivity, 3-dimensional computed tomography with 80% to 81.8% sensitivity, magnetic resonance imaging with 80% sensitivity, and ultrasound with 92.5% sensitivity. For patients who underwent hip arthroscopy, the pooled prevalence of AIIS impingement was 18%. Significant improvement between pre- and postoperative clinical outcomes was observed: 25.75 points for the modified Harris hip score (mHHS), 46.88 points for the Hip Outcome Score-Sport subscale, 20.85 points for the Nonarthritic Hip Score, and -2.92 points for the pain visual analog scale. The minimal clinically important difference on the mHHS was exceeded by 94% of patients. The pooled incidence of surgical complications was 1%. Of 6 included studies on diagnostic accuracy, 2 were identified as having a low risk of bias, and 4 included >2 factors with a high risk of bias. All 9 included studies on treatment outcomes had at least 1 factor with a high risk of bias. Several imaging modalities assist in the diagnosis of AIIS impingement. The overall prevalence of AIIS impingement in patients that underwent hip arthroscopy was 18%. Clinical outcomes after arthroscopic AIIS decompression were generally favorable, with a relatively low rate of surgical complications.

Hip Impingement Location in Maximal Hip Flexion in Patients With Femoroacetabular Impingement With and Without Femoral Retroversion

Background: Symptomatic patients with femoroacetabular impingement (FAI) have limitations in daily activities and sports and report the exacerbation of hip pain in deep flexion. Yet, the exact impingement location in deep flexion and the effect of femoral version (FV) are unclear. Purpose: To investigate the acetabular and femoral locations of intra- or extra-articular hip impingement in flexion in patients with FAI with and without femoral retroversion. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An institutional review board–approved retrospective study involving 84 hips (68 participants) was performed. Of these, symptomatic patients (37 hips) with anterior FAI and femoral retroversion (FV <5°) were compared with symptomatic patients (21 hips) with anterior FAI (normal FV) and with a control group (26 asymptomatic hips without FAI and normal FV). All patients were symptomatic, had anterior hip pain, and had positive anterior impingement test findings. Most of the patients had hip/groin pain in maximal flexion or deep flexion or during sports. All 84 hips underwent pelvic computed tomography (CT) to measure FV as well as validated dynamic impingement simulation with patient-specific CT-based 3-dimensional models using the equidistant method. Results: In maximal hip flexion, femoral impingement was located anterior-inferior at 4 o’clock (57%) and 5 o’clock (32%) in patients with femoral retroversion and mostly at 5 o’clock in patients without femoral retroversion (69%) and in asymptomatic controls (76%). Acetabular intra-articular impingement was located anterior-superior (2 o’clock) in all 3 groups. In 125° of flexion, patients with femoral retroversion had a significantly (P < .001) higher prevalence of anterior extra-articular subspine impingement (54%) and anterior intra-articular impingement (89%) compared with the control group (29% and 62%, respectively). Conclusion: Knowing the exact location of hip impingement in deep flexion has implications for surgical treatment, sports, and physical therapy and confirms previous recommendations: Deep flexion (eg, during squats/lunges) should be avoided in patients with FAI and even more in patients with femoral retroversion. Patients with femoral retroversion may benefit and have less pain when avoiding deep flexion. For these patients, the femoral location of the impingement conflict in flexion was different (anterior-inferior) and distal to the cam deformity compared with the location during the anterior impingement test (anterior-superior). This could be important for preoperative planning and bone resection (cam resection or acetabular rim trimming) during hip arthroscopy or open hip preservation surgery to ensure that the region of impingement is appropriately identified before treatment.

Minimum 2-Year Outcomes and Return to Sports of Competitive Athletes Who Undergo Subspine Decompression During Primary Hip Arthroscopy for Femoroacetabular Impingement Syndrome and Subspine Impingement: A Propensity-Matched Controlled Study

Background: Patient-reported outcomes (PROs) and return to sports (RTS) have not been established in athletes undergoing primary hip arthroscopy and subspine decompression for femoroacetabular impingement syndrome (FAIS) and subspine impingement (SSI). Purpose: (1) To report minimum 2-year PROs and RTS in competitive athletes undergoing primary hip arthroscopy for treatment of FAIS with subspine decompression for treatment of SSI and (2) to compare clinical results with a matched control group of athletes without SSI. Study Design: Cohort study, Level of evidence, 3. Methods: Data were reviewed for professional, collegiate, and high school athletes undergoing primary hip arthroscopy for FAIS with arthroscopic subspine decompression for SSI between February 2011 and October 2018. Inclusion criteria included preoperative and minimum 2-year follow-up scores for the modified Harris Hip Score, Nonarthritic Hip Score, Hip Outcome Score–Sport Specific Subscale, and visual analog scale for pain. Rates of achieving the minimal clinically important difference (MCID) were also calculated. For comparison, athletes in the SSI group were propensity matched according to age at the time of surgery, sex, body mass index, lateral center-edge angle, alpha angle, sport level, acetabular labrum articular disruption grade, and sport type to a control group of athletes without SSI. Results: A total of 30 SSI athletes were included in the study, with a mean plus or minus standard deviation follow-up of 32.1 ± 7.1 months and age of 20.9 ± 5.7 years. The SSI cohort demonstrated significant improvement in all recorded PROs (P < .001), returned to sports at high rates (88.5%), and achieved the MCID for the Hip Outcome Score–Sport Specific Subscale at a high rate (80.0%). Furthermore, these patients had a low rate of undergoing revision surgery (6.7%). When compared with a propensity-matched control group of 59 athletes, the SSI group demonstrated similar rates of RTS, revision, and achieving the MCID for all PROs. Conclusion: Competitive athletes with FAIS and SSI who underwent primary hip arthroscopy and subspine decompression had favorable outcomes and high RTS rates at minimum 2-year follow-up. These results were comparable with those of a control group of athletes without SSI undergoing primary hip arthroscopy.

Outcomes After Management of Subspine and Femoroacetabular Impingement Using a Direct Anterior Mini-Open Approach.

Background:Subspine impingement (SSI) has been commonly managed with arthroscopic decompression. However, arthroscopic decompression is a demanding technique, as under- or over-resection of the anterior inferior iliac spine (AIIS) could lead to inferior outcomes. An anterior mini-open approach has also been used in the management of femoroacetabular impingement (FAI), and it could provide adequate visualization of the anterior hip joint without a long learning curve.Purpose/Hypothesis:The objective of the current study was to compare the outcomes of SSI patients with FAI who underwent arthroscopic subspine decompression and osteoplasty with a group undergoing subspine decompression and osteoplasty using a modified direct anterior mini-open approach. It was hypothesized that there would be no significant difference in outcomes between the groups.Study Design:Cohort study; Level of evidence, 3.Methods:We reviewed the records of SSI patients who underwent decompression surgery (arthroscopic or mini-open) at our institution from June 1, 2015 to December 31, 2016. Both groups underwent the same postoperative rehabilitation protocol. Preoperative and 2-year postoperative patient-reported outcomes were compared using the modified Harris Hip Score (mHHS), International Hip Outcome Tool–33 (iHOT–33), and Hip Outcome Score—Activities of Daily Living (HOS–ADL). Major and minor complications as well as reoperation rates were recorded.Results:Included were 47 patients (49 hips) who underwent subspine decompression using an anterior mini-open approach and 35 patients (35 hips) who underwent arthroscopic subspine decompression. There were no differences in demographic and radiological parameters between the groups, and patients in both groups showed significant improvement in all outcome scores at follow-up. The pre- to postoperative improvement in outcome scores was also similar between groups (mini-open vs arthroscopy: mHHS, 26.30 vs 27.04 [P = .783]; iHOT–33, 35.76 vs 31.77 [P = .064]; HOS–ADL, 26.09 vs 22.77 [P = .146]). In the mini-open group, 10 of the 47 patients had temporary meralgia paresthetica, and fat liquefaction was found in 1 female patient. There were no reoperations in the mini-open group.Conclusion:Subspine decompression using the anterior mini-open approach had similar outcomes to arthroscopic decompression in the management of SSI. The lateral femoral cutaneous nerve should be protected carefully during use of the anterior mini-open approach.

The case of 'A Rhino Horn': case report and proposal for modification to the Hetsroni and Kelly classification.

Subspine impingement syndrome by definition involves a prominent antero-inferior iliac spine (AIIS) which can lead to impingement on the femoral neck thereby causing symptoms. We present the case of a 22-year-old semi-professional athlete who presented with a Type III AIIS morphology leading to subspine impingement syndrome and was managed via a mini open anterior approach. Radiological examination revealed a fairly prominent left AIIS resembling the ‘horn of a rhino’ extending to the trochanteric region anteriorly. A mini-anterior surgical approach was utilized for the resection of the ‘rhino horn’ and the rectus femoris was reattached. The patient remained asymptomatic at the one-year follow-up and had resumed weightlifting. Following this case, we propose a new classification of the type III AIIS morphology in view of the clinical presentation. The AIIS type III-Standard represents an extension from the acetabular rim to less than 1 cm (type III-S) and type III-Large, with an extension from the acetabular rim beyond 1 cm (type III-L). The type III-L will further be divided into two groups based on its relation to the ilium, type III-Lr (‘rib shape’) and type III-Lrh (‘rhino horn’).

Intraoperative Findings and Clinical Outcomes Associated With Arthroscopic Management of Subspine Impingement: A Propensity-Matched, Controlled Study

(1) To investigate intra-articular damage in the hip joint associated with subspine impingement (SSI); (2) to evaluate clinical outcomes of arthroscopic treatment of hips with SSI; and (3) to compare the findings and outcomes to a control group without SSI. Eligible patients had arthroscopic treatment for femoroacetabular impingement (FAI) concurrent with SSI between January 2015 and December 2017. Inclusion criteria consisted of preoperative and minimum 2-year patient-reported outcomes and preoperative measurements for Tönnis, lateral center edge angle, and alpha angle. Included patients were propensity-matched in a 1:3 ratio to patients who had FAI without SSI. Patient-reported outcomes were compared between groups. Minimal clinically important difference was calculated for modified Harris Hip Score (mHHS) and Hip Outcome Score-Sports Specific Subscale (HOS-SSS). Fifty SSI cases were matched to 150 patients who had FAI without SSI. A greater proportion of the SSI cohort required labral reconstruction (P= .010). The size and locations for labral tears and chondral defects were comparable between groups (P > .05). Both groups demonstrated similar minimum 2-year outcomes for mHHS (P= .103), Nonarthritic Hip Score (P= .200), HOS-SSS (P= .119), visual analog scale (P= .231), international Hip Outcome Tool-12 (P=.300), Short Form-12 Mental (P=.426), Short Form-12 Physical (P= .328), Veterans RAND 12-Item Health Survey, Mental (P= .419), and Veterans RAND 12-Item Health Survey, Physical (P= .316). The percentage of patients achieving minimal clinically important difference for mHHS and HOS-SSS was similar (P > .05). Survivorship was 96.0% and 98.7% for the SSI and control cohorts at 2 years, respectively. Arthroscopic treatment of hips with SSI with subspine decompression and concomitant treatment of labral tears and FAI yielded significant improvement in patients' outcomes, which compared favorably with the control group. SSI may correlate with more complex labral tears, not amenable to repair, and complete tears of the ligamentum teres. Other findings, such as location and size of intra-articular damage, were similar between the cohorts. III, case-control study.

Capsule-Preserving Approach to Arthroscopic Decompression of the Anterior Inferior Iliac Spine

Hip arthroscopy techniques have evolved to treat a wide range of extra-articular pathologies. Subspine impingement commonly occurs in femoroacetabular impingement, particularly in athletes with a high range of motion, patients with low degrees of femoral version, and those with large subspine deformities. A reliable technique that preserves the hip capsule would be helpful for hip arthroscopy surgeons. This note details our technique using pericapsular windows proximal to the interportal capsulotomy to access and decompress a subspine deformity in the setting of hip femoroacetabular impingement.

Prevalence of Anterior Inferior Iliac Spine Dysmorphism and Development of a Novel Classification System: An Anatomic Study of 1,797 Cadaveric Specimens.

Purpose: Subspine impingement occurs due to a morphologically abnormal anterior inferior iliac spine (AIIS), capable of causing impingement against the distal femoral neck. The purpose of this investigation was to determine the prevalence of AIIS dysmorphism based on specimen sex, race, and age, while introducing a novel anatomic-based classification system.Methods: A total of 1,797 adult cadaveric specimens (n = 3,594 hemipelvises) were analyzed. AIIS with the potential for subspine impingement (SSI) was recorded in each specimen by two independent authors. Specimens with AIIS dysmorphism were then reexamined to determine SSI subtype using a novel descriptive anatomic classification system.Results: AIIS dysmorphism was present in 6.4% (n = 115 of 1,797 specimens) of specimens and 5.2% (n = 186 of 3,594) of hemipelvises. Dysmorphism was significantly more common in male specimens (p = 0.04) and African–American specimens (p = 0.04). No significant overall difference in prevalence was appreciated based on specimen age (p = 0.89). Subtype classification found that 67% of hemipelvises possessed a columnar type AIIS, 30% were bulbous and 3% hook type. Males possessed a significantly higher prevalence of columnar type AIIS dysmorphism (p < 0.001). No significant overall differences in anatomic classification were appreciated based on race (p = 0.12) or when analyzed based on age (p = 0.34).Conclusion: AIIS dysmorphism was present in 6.4% of the 1,797 cadaveric specimens evaluated. African-American and male specimens possessed significantly higher prevalence of AIIS dysmorphism, with no significant difference based on specimen age. Columnar type AIIS dysmorphism was most common. Anatomic classification was not significantly different based on specimen race or age.Level of Evidence: Case Series, Level IV.

Acetabular Rim Disorders/Pincer-type Femoroacetabular Impingement and Hip Arthroscopy.

Femoroacetabular impingement (FAI) can lead to acetabular impaction, chondral injury, and labral pathology secondary to deformities of the proximal femur (CAM-type FAI), acetabulum (pincer-type FAI), or with combined FAI. While the majority of cases are of the combined type, this paper focuses on acetabular overcoverage/pincer-type deformities. Various pincer subtypes include focal anterior overcoverage, global retroversion, global overcoverage/profunda, protrusio, subspine impingement, and os acetabuli/rim fracture variants. A thorough history and physical examination, plain radiographs, magnetic resonance imaging, 3-dimensional computerized tomography, and diagnostic injections can lead to an accurate assessment of pincer-type variants. Appropriately indicated arthroscopic management techniques and pearls for the various pincer subtypes can lead to improved patient-related outcome measures and a high rate of return to athletic activity for the majority of these patients.

Subspine Hip Impingement: Clinical and Radiographic Results of its Arthroscopic Treatment.

Objective To evaluate the clinical and radiographic results as well as complications related to patients undergoing arthroscopic treatment of subspine hip impingement. Methods We retrospectively evaluated 25 patients (28 hips) who underwent arthroscopic treatment of subspine impingement between January 2012 and June 2018. The mean follow-up was 29.5 months, and the patients were evaluated clinically by using the Harris hip score modified by Byrd (MHHS), the non-arthritic hip score (NAHS), and in terms of internal rotation and hip flexion. In addition, the following items were evaluated by imaging exams: the center-edge (CE) acetabular angle, the Alpha angle, the presence of a sign of the posterior wall, the degree of arthrosis, the presence of heterotopic hip ossification, and the Hetsroni classification for subspine impingement. Results There was an average postoperative increase of 26.9 points for the MHHS, 25.4 for the NAHS ( p < 0.0001), 10.5° in internal rotation ( p < 0.0024), and 7.9° for hip flexion ( p < 0.0001). As for the radiographic evaluation, an average reduction of 3.3° in the CE angle and of 31.6° for the Alpha angle ( p < 0.0001). Eighteen cases (64.3%) were classified as grade 0 osteoarthritis of Tönnis, and 10 (35.7%) were classified as Tönnis grade 1. Two cases (7.1%) presented grade 1 ossification of Brooker. Most hips ( n = 15, 53.6%) were classified as type II of Hetsroni et al. Conclusion In the present study, patients undergoing arthroscopic treatment with subspine impingement showed improvement in clinical aspects and radiographic patterns measured postoperatively, with an average follow-up of 29.5 months.

Femoroacetabular Impingement and Acetabular Labral Tears - Part 2: Clinical Diagnosis, Physical Examination and Imaging.

The clinical diagnosis of femoral acetabular impingement (FAI) continues to evolve as the understanding of normal and pathological hips progresses. Femoral acetabular impingement is currently defined as a syndrome in which the diagnosis consists of the combination of a previously-obtained comprehensive clinical history, followed by a consistent and standardized physical examination with specific orthopedic maneuvers. Additionally, radiographic and tomographic examinations are used for the morphological evaluation of the hip, and to ascertain the existence of sequelae of childhood hip diseases and the presence of osteoarthritis. The understanding of the femoral and acetabular morphologies and versions associated with images of labral and osteochondral lesions obtained through magnetic resonance imaging (MRI) contributes to the confirmation of this syndrome in symptomatic patients, and helps in the exclusion of differential diagnoses such as iliopsoas tendon snaps, subspine impingement, ischiofemoral impingement, and other hip joint pathologies.