Common characteristics of shoulder injury related to vaccine administration following COVID-19 vaccination: a comprehensive systematic review.

BACKGROUND: The pathogenesis of shoulder injury related to vaccine administration (SIRVA) is incompletely understood, but it is postulated to be an immune-mediated inflammatory response to a vaccine antigen, leading to shoulder pain and dysfunction. The purpose of this investigation is to systematically review the literature related to SIRVA specifically after the COVID-19 vaccination by describing the diagnostic and clinical characteristics, diagnoses associated with SIRVA, and incidence between vaccine types. METHODS: A systematic review was performed to identify level I to IV studies and case descriptions of shoulder pain occurring after COVID-19 vaccination. To confirm that no studies were missing from the systematic review, references of studies from the initial search were scanned for additional relevant studies. RESULTS: A total of 22 studies, comprised of 81 patients, were identified meeting the inclusion/exclusion criteria. Reports were most commonly published from countries in Asia (53.1%; n = 43/81). The most commonly described vaccines were Oxford-AstraZeneca at 37.0% (n = 30/81) and Pfizer-BioNTech at 33.3% (n = 27/81). Symptoms occurred most commonly after at least 72 hours of administration (30.9%, n = 25/81). One hundred percent of patients (n = 81/81) described pain as an associated symptom and 90.1% of patients (n = 73/81) described multiple symptoms. The diagnostic modalities utilized to identify a specific pathology consisted of magnetic resonance imaging (55.6%; n = 45/81), ultrasound (28.4; n = 23/81), radiograph (25.9%; n = 21/81), and computed tomography (4.9%; 4/81). Nearly a third of patients (32.1%; n = 26/81) were diagnosed with bursitis, while 22 (27.2%) were diagnosed with adhesive capsulitis, 17 (21.0%) with either rotator cuff tear or tendinopathy, and 14 (17.3%) with polymyalgia rheumatica or polymyalgia rheumatica-like syndrome. The 2 most common treatment options were physical therapy (34.6%; n = 28/81) and nonsteroidal anti-inflammatory medications (33.3%; 27/81). The majority of SIRVA cases (52.1%; n = 38/73) completely resolved within a few weeks to months. CONCLUSION: Despite the limited quality and lack of large-scale studies, it is important for providers to recognize SIRVA as a potential risk factor as the number of patients receiving COVID-19 vaccinations and boosters continues to rise.

Femoral Version May Impact Hip Arthroscopy Outcomes in Select Patient Populations: A Systematic Review.

PURPOSE: To provide further clarity regarding the management of patients with abnormal femoral version in the setting of hip arthroscopy and will discuss the definition of femoral version, the diagnostic and clinical evaluation of abnormal femoral version, and several described measurement techniques. METHODS: A systematic review was conducted in literature published before August 2021 that measured femoral version and reported patient-reported outcomes measures or rates of subsequent procedures following hip arthroscopy. Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed and the electronic databases, PubMed, OvidMedLine, Scopus, and Web of Science were searched. Two blinded reviews screened and evaluated data quality using the Newcastle-Ottawa Scale. RESULTS: Eighteen studies were included with 11 studies reporting patient outcomes and 7 studies reporting rates of subsequent procedures. The most commonly used definition of femoral version was 5° to 20° of femoral anteversion. Computed tomography scan was the most commonly used imaging modality. The majority of studies (7 of 11) demonstrated that femoral version does not have an impact on patient-reported outcomes measures and is not predictive of clinically meaningful improvement scores. However, in select studies, patients with femoral retroversion were found to experience slightly inferior outcomes following hip arthroscopy for femoroacetabular impingement. While femoral retroversion may be a risk factor for subsequent procedures, 3 of 7 studies refute this claim. Although in patients with borderline hip dysplasia, excessive femoral anteversion led to greater rates of subsequent hip procedures. CONCLUSIONS: While the majority of studies show that femoral version does not have an impact on patient-reported outcomes following hip arthroscopy, those with femoral retroversion and with excessive anteversion with coexisting borderline hip dysplasia need to be educated on their increased risk of subsequent operation. Ultimately, this review suggests that clinical improvement can likely be achieved regardless of femoral version. LEVEL OF EVIDENCE: IV; systematic review of Level I-IV studies.

Evaluating the role of graft integrity on outcomes: clinical and imaging results following superior capsular reconstruction.

BACKGROUND: Superior capsular reconstruction (SCR) addresses massive, irreparable rotator cuff tears in young patients. The purpose of this study was to retrospectively evaluate clinical outcomes and graft integrity in patients following SCR. METHODS: Thirty-four consecutive patients undergoing SCR by 2 surgeons with minimum 2-year follow-up were identified. Functional outcomes were obtained, including Simple Shoulder Test (SST), American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES), visual analog scale (VAS), and Single Assessment Numeric Evaluation (SANE) scores. Graft integrity was evaluated on magnetic resonance images (MRIs). RESULTS: Thirty-five shoulders in 34 patients were identified. Four patients underwent subsequent surgery. The mean preoperative scores were SST 21.6 ± 17.6, ASES 28.3 ± 10.1, SANE 50.6 ± 22.1, and VAS 6.6 ± 1.7. The mean postoperative outcomes were SST 79.1 ± 19.6, ASES 79.9 ± 17.4, SANE 74.3 ± 18.7, and VAS 1.5 ± 2.2. There was statistically significant improvement in SST, ASES, and VAS following SCR. MRI revealed graft failure in 62% (n = 13 of 21) of shoulders. Radiographic evidence of graft healing did not have any effect on SST, ASES, SANE, or VAS scores. CONCLUSION: Given the high rate of graft failure without a significant difference in clinical outcomes, graft healing after SCR might not be an independent predictor of success. The improved clinical improvement in patients undergoing SCR may be due to other known beneficial aspects of the procedure, including partial rotator cuff repair, débridement, and biceps management.

Does Pelvic Rotation Alter Radiologic Measurement of Anterior and Lateral Acetabular Coverage?

PURPOSE: The purpose of this study was to determine the radiologic tolerance of the lateral center edge angle (LCEA) and anterior center edge angle (ACEA) to pelvic rotation. METHODS: Eleven dry cadaveric pelvises from an osteological collection were reconstructed and placed in anatomic position with corresponding bilateral proximal femurs. Conventional anteroposterior (AP) and false-profile (FP) pelvic radiographs were taken at 5° increments with fluoroscopy from 0° to 25° of rotation. LCEA and ACEA were measured for conventional and rotated AP and FP fluoroscopic views, respectively. Statistical analysis was conducted to determine the error in ACEA and LCEA with pelvic rotation. RESULTS: The mean LCEA was 29.1° (95% confidence interval [CI], 25.5°-32.7°). Mean ACEA was 38.9° (95% CI, 34.1°-43.8°). There was significant change in the LCEA past 10° of rotation (P = .041). There was significant change in the ACEA with 5o or more of rotation (P < .001). The FP view rotated 40° from an AP view produced 6.8° (95% CI, 4.7-8.9) of error, whereas one rotated 90° from an AP view produced 13.2° (95% CI, 11.2°-15.3°) of error in the ACEA. An AP view rotated 25° toward the x-ray beam produced 2.3° (95% CI, 1.1°-3.4°) error, whereas one rotated 25° away from the beam produced 2.6° (95% CI, 1.5°-3.8°) of error. CONCLUSIONS: Rotation of AP and FP radiographs significantly affects the measured values of the LCEA and ACEA, respectively. The ACEA experiences more dramatic changes with rotation of the FP view compared with the LCEA with the same amount of rotation of an AP view. This study illustrates the importance of verifying the quality of the FP radiograph when using ACEA to guide therapy for hip pathology. CLINICAL RELEVANCE: This study emphasizes the importance of evaluating pelvic rotation when using the center edge angle to assess femoral head coverage.

Unplanned Admissions Following Hip Arthroscopy: Incidence and Risk Factors.

PURPOSE: To determine the rate of and risk factors for 30-day unplanned admissions following hip arthroscopy in a U.S. METHODS: Patients undergoing hip arthroscopy were identified in the American College of Surgeons National Surgical Quality Improvement Program database using validated Current Procedural Terminology and International Classification of Diseases, Ninth Revision and Tenth Revision codes. Patient demographics, comorbidities, preoperative laboratory values, surgical details, and postoperative outcomes were compared between patients with unplanned admissions and those without. Univariate analysis comparing study cohorts was performed using 2-tailed Student t tests with Levene's test for equality of variance or χ2/Fisher exact tests as appropriate. Using variables that were significant in the univariate analysis, we created Cox proportional hazard models to identify independent predictors for unplanned admission. RESULTS: A total of 1931 cases of hip arthroscopy were identified. There were 18 cases of unplanned admissions within 30 days of index procedure (0.9%). The median time to unplanned admission was 14.5 days (interquartile range: 3.875-25.125 days). The most common reasons for admission were surgical-site infection (11.1%), wound complications (11.1%), and thromboembolic events (11.1%). There were 4 patients who required reoperation (22.2%). There were 7 cases (39.0%) that were readmitted for reasons unrelated to the index hip arthroscopy procedure. Multivariate analysis identified increasing body mass index, chronic corticosteroid use, and perioperative blood transfusion as factors independently associated with increased risk for unplanned admission. CONCLUSIONS: There exists a low incidence of 30-day unplanned admission, predominantly secondary to surgical-site infections, wound complications, and thromboembolic events. Independent risk factors for unplanned admission include greater body mass index, chronic corticosteroid use, and perioperative transfusions. LEVEL OF EVIDENCE: Level III Retrospective Cohort Study.

Indications and Outcomes of Arthroscopic Labral Reconstruction of the Hip: A Systematic Review.

PURPOSE: The primary purpose of this investigation was to systematically evaluate the literature for the current indications and outcomes of arthroscopic labral reconstruction of the hip. Our secondary purpose was to evaluate the role of arthroscopic labral reconstruction in the management of reparable labral tears. METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines using a PRISMA checklist. Studies published between June 2009 and June 2018 that evaluated outcomes after arthroscopic labral reconstruction with a minimum of 1 year of follow-up were included. RESULTS: Eleven studies met the inclusion and exclusion criteria. A total of 373 patients were identified. Of the 11 studies, 9 reported that an irreparable labrum was their indication for reconstruction, with 8 reporting that this was ultimately determined intraoperatively. Substantial variability in surgical technique, graft choice, and concurrent pathology was found. All 11 studies used at least 1 validated functional outcome metric to evaluate surgical outcomes, with all studies reporting improvement greater than the minimal clinically important difference. Donor-site pain was the most common complication, although it was reported in only 2 studies. Reported rates of revision surgery and conversion to arthroplasty were low (range, 0%-9.1% for both). CONCLUSIONS: All 11 studies included in this systematic review reported clinically significant functional improvements after arthroscopic labral reconstruction and low rates of complications, revision surgery, and progression of arthritis, although graft types and concomitant procedures confound the results. The most common indication for reconstruction was a deficient labrum on intraoperative evaluation. The 6 studies that evaluated patient satisfaction reported favorable results, with a range of 6.73 to 8.7. LEVEL OF EVIDENCE: Level IV, systematic review of Level III and IV studies.

Revisiting the Anteroinferior Iliac Spine: Is the Subspine Pathologic? A Clinical and Radiographic Evaluation.

BACKGROUND: Subspine impingement is a recognized source of extraarticular hip impingement. Although CT-based classification systems have been described, to our knowledge, no study has evaluated the morphology of the anteroinferior iliac spine (AIIS) with plain radiographs nor to our knowledge has any study compared its appearance between plain radiographs and CT scan and correlated AIIS morphology with physical findings. Previous work has suggested a correlation of AIIS morphology and hip ROM but this has not been clinically validated. Furthermore, if plain radiographs can be found to adequately screen for AIIS morphology, CT could be selectively used, limiting radiation exposure. QUESTIONS/PURPOSES: The purposes of this study were (1) to determine the prevalence of AIIS subtypes in a cohort of patients with symptomatic femoroacetabular impingement; (2) to compare AP pelvis and false profile radiographs with three-dimensional (3-D) CT classification; and (3) to correlate the preoperative hip physical examination with AIIS subtypes. METHODS: A retrospective study of patients undergoing primary hip arthroscopy for femoroacetabular impingement syndrome was performed. Between February 2013 and November 2016, 601 patients underwent hip arthroscopy. To be included here, each patient had to have undergone a primary hip arthroscopy for the diagnosis of femoroacetabular impingement syndrome. Each patient needed to have an interpretable set of plain radiographs consisting of weightbearing AP pelvis and false profile radiographs as well as full documentation of physical findings in the medical record. Patients who additionally had a CT scan with 3-D reconstructions were included as well. During the period in question, it was the preference of the treating surgeon whether a preoperative CT scan was obtained. A total of 145 of 601 (24%) patients were included in the analysis; of this cohort, 54% (78 of 145) had a CT scan and 63% (92 of 145) were women with a mean age of 31 ± 10 years. The AIIS was classified first on patients in whom the 3-D CT scan was available based on a previously published 3-D CT classification. The AIIS was then classified by two orthopaedic surgeons (TGM, MRK) on AP and false profile radiographs based on the position of its inferior margin to a line at the lateral aspect of the acetabular sourcil normal to vertical. Type I was above, Type II at the level, and Type III below this line. There was fair interrater agreement for AP pelvis (κ = 0.382; 95% confidence interval [CI], 0.239-0.525), false profile (κ = 0.372; 95% CI, 0.229-0.515), and 3-D CT (κ = 0.325; 95% CI, 0.156-0.494). There was moderate to almost perfect intraobserver repeatability for AP pelvis (κ = 0.516; 95% CI, 0.284-0.748), false profile (κ = 0.915; 95% CI, 0.766-1.000), and 3-D CT (κ = 0.915; 95% CI, 0.766-1.000). The plane radiographs were then compared with the 3-D CT scan classification and accuracy, defined as the proportion of correct classification out of total classifications. Preoperative hip flexion, internal rotation, external rotation, flexion adduction, internal rotation, subspine, and Stinchfield physical examination tests were compared with classification of the AIIS on 3-D CT. Finally, preoperative hip flexion, internal rotation, and external rotation were compared with preoperative lateral center-edge angle and alpha angle. RESULTS: The prevalence of AIIS was 56% (44 of 78) Type I, 39% (30 of 78) Type II, and 5% (four of 78) Type III determined from the 3-D CT classification. For the plain radiographic classification, the distribution of AIIS morphology was 64% (93 of 145) Type I, 32% (46 of 145) Type II, and 4% (six of 145) Type III on AP pelvis and 49% (71 of 145) Type I, 48% (70 of 145) Type II, and 3% (four of 145) Type III on false profile radiographs. False profile radiographs were more accurate than AP pelvis radiographs for classification when compared against the gold standard of 3-D CT at 98% (95% CI, 96-100) versus 80% (95% CI, 75-85). The false profile radiograph had better sensitivity for Type II (97% versus 47%, p < 0.001) and specificity for Types I and II AIIS (97% versus 53%, p < 0.001; 98% versus 90%, p = 0.046) morphology compared with AP pelvis radiographs. There was no correlation between AIIS type as determined by 3-D CT scan and hip flexion (rs = -0.115, p = 0.377), internal rotation (rs = 0.070, p = 0.548), flexion adduction internal rotation (U = 72.00, p = 0.270), Stinchfield (U = 290.50, p = 0.755), or subspine tests (U = 319.00, p = 0.519). External rotation was weakly correlated (rs = 0.253, p = 0.028) with AIIS subtype. Alpha angle was negatively correlated with hip flexion (r = -0.387, p = 0.002) and external rotation (r = -0.238, p = 0.043) and not correlated with internal rotation (r = -0.068, p = 0.568). CONCLUSIONS: The findings in this study suggest the false profile radiograph is superior to an AP radiograph of the pelvis in evaluating AIIS morphology. Neither preoperative hip internal rotation nor impingement tests correlate with AIIS type as previously suggested questioning the utility of the AIIS classification system in identifying pathologic AIIS anatomy. LEVEL OF EVIDENCE: Level III, diagnostic study.

Recurrent Labral Tearing on Magnetic Resonance Imaging Is Not Predictive of Diminished Participation Among National Football League Athletes.

PURPOSE: To investigate the prevalence of shoulder labral repair and utility of magnetic resonance imaging (MRI) in determining the risks of recurrent labral tearing and impact on future participation in the National Football League (NFL). METHODS: Athletes invited to the NFL Combine between 2012 and 2015 were retrospectively reviewed. Athletes with a history of labral repair and MRI of the operative shoulder at the Combine were included in the study for further analysis, excluding athletes without a history of labral repair, labral repair without MRI at the Combine, additional procedure to the operative shoulder, or athletes still undergoing rehabilitation at the time of the Combine after labral repair. All MRIs were reviewed to determine initial labral repair location, the presence of recurrent tearing, and any concomitant shoulder pathology. Prospective information on future NFL participation in regard to draft status, games played, and games started in the athlete's first NFL season after the Combine was compared between athletes with a history of labral repair with and without recurrent tearing versus all other athletes participating in the Combine. RESULTS: A total of 132 (10.1%) athletes underwent 146 shoulder labral repair procedures before the NFL Combine, of whom 32% (n = 39 athletes, n = 46 shoulders) had recurrent labral tears on MRI. Athletes with recurrent tears were more likely to have undergone bilateral labral repairs (P = .048) and possess concomitant shoulder pathology (P < .001). Recurrent labral tearing was significantly more common in the posterior labrum in athletes with a history of posterior labral repairs (P = .032). Prospective participation in the NFL in terms of games played (P = .38) or started (P = .98) was not significantly reduced in athletes with a history of labral repair compared with those without repair. Participation was not diminished in athletes with recurrent labral tears compared with those with intact repairs or those with evidence of degenerative joint disease. CONCLUSIONS: Athletes invited to the NFL Scouting Combine with a history of bilateral repair, posterior labral repair, and concomitant shoulder pathology are at high risk of recurrent labral tearing on MRI. No significant reduction in NFL participation the year after the Combine was seen in athletes with a history of labral repair, recurrent labral tearing, or degenerative joint disease who were successfully drafted into the NFL. In athletes with a history of labral repair, assessment of labral integrity on MRI alone is not predictive of future short-term participation. LEVEL OF EVIDENCE: Level IV, prognostic study-case series.

Amateur and Recreational Athletes Return to Sport at a High Rate Following Hip Arthroscopy for Femoroacetabular Impingement.

PURPOSE: To compare the return-to-play rates, patient-reported outcome (PRO) scores, and satisfaction between high-level amateur athletes and recreational athletes and to evaluate for differences in ability to return to sport in these groups based on patient-related and sport-related characteristics. METHODS: Clinical data were retrieved for 66 (26 male/40 female) consecutive athletes undergoing hip arthroscopy for femoroacetabular impingement. Athletes were classified as high-level amateur or recreational. Athletes were also divided into 6 distinct sporting categories based on the physical demands on the hip. Preoperative and 2-year PROs including a sport-specific questionnaire, modified Harris Hip Score (MHHS), and Hip Outcome Scores with Activities of Daily Living (HOS-ADL) and Sports-Specific (HOS-SS) subscales were collected. RESULTS: Of the 66 patients, 49 were recreational and 17 were high-level amateur athletes (10 high school and 7 collegiate). High-level athletes were significantly younger than recreational athletes (18.4 ± 2.3 years vs 29.7 ± 6.8 years; P < .001). After 2 years, all PROs had improved significantly, with no differences between the 2 athletic groups. There was a high overall rate of return for both recreational and high-level amateur athletes (94% vs 88%; P = .60). Increasing preoperative withdrawal time from sport prior to surgery was associated with decreased HOS-SS (r = 0.33; P = .04) and MHHS scores (r = 0.02; P = .02). Overall, athletes who had withdrawn from sport for greater than 8 months before surgery returned to sport significantly more slowly (P = .01). Increasing body mass index (BMI) was associated with lower improvements in HOS (r = 0.26; P = .04) and MHHS scores (r = 0.38; P < .01). CONCLUSIONS: Recreational athletes, despite being significantly older than their high-level counterparts, return to play at a similar high rate and with comparable PROs. Increasing preoperative cessation time from sport significantly prolongs return to sport. Additionally, increasing preoperative cessation from sport and higher preoperative BMI were associated with decreased improvements in PROs. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Prevalence of Surgical Repair for Athletic Pubalgia and Impact on Performance in Football Athletes Participating in the National Football League Combine.

PURPOSE: To examine the prevalence and impact of athletic pubalgia (AP) surgery in elite American football athletes participating in the National Football League (NFL) Combine. METHODS: Results from 1,311 athletes participating in the Combine from 2012 to 2015 were evaluated. Athletes with a history of AP repair were identified using the NFL Combine Database. Athlete history and available imaging was reviewed. NFL performance based on draft status, games played, games started, and current status in the NFL was gathered using publicly available databases. Statistical analysis was performed to detect for significant associations between athlete history and NFL performance in the presence of AP repair and pelvic pathology on postsurgical magnetic resonance imaging (MRI). RESULTS: AP repair was identified in 4.2% (n = 55) of athletes. MRI was performed in 35% (n = 19 of 55) with AP repair, of which 53% (n = 10 of 19) had positive pathology. Athletes with repair were not at risk of playing (P = .87) or starting (P = .45) fewer regular season games, going undrafted (P = .27), or not being on an active NFL roster (P = .51). Compared with athletes with negative imaging findings, positive pathology on MRI did not have a significant impact on games played (P = .74), games started (P = .48), draft status (P = .26), or being on an active roster (P = .74). Offensive linemen (P = .005) and athletes with a history of repair within 1 year of the Combine (P = .03) had a significantly higher risk of possessing positive pathology on MRI. CONCLUSIONS: Athletes with a history of successful AP surgery invited to the NFL Combine and those with persistent pathology on MRI are not at increased risk for diminished performance in the NFL. Offensive linemen and athletes less than 1 year out from surgery have a higher risk for positive MRI findings at the pubic symphysis. LEVEL OF EVIDENCE: Level IV, prognostic study-case series.

Does the Hip Capsule Remain Closed After Hip Arthroscopy With Routine Capsular Closure for Femoroacetabular Impingement? A Magnetic Resonance Imaging Analysis in Symptomatic Postoperative Patients.

PURPOSE: The purpose of this study was to examine the hip capsule in a subset of symptomatic patients who underwent capsular closure during hip arthroscopy. METHODS: All patients undergoing primary hip arthroscopy for femoroacetabular impingement (FAI) with routine capsular closure between January 1, 2012, and December 31, 2015, were eligible. Only patients with unilateral surgery and a postoperative magnetic resonance imaging (MRI; ordered for persistent symptoms) were included. Four independent reviewers evaluated each hip capsule for thickness and the absence or presence of defects. RESULTS: During the study, 1,463 patients had hip arthroscopy for FAI with routine capsular closure, and 53 (3.6%) underwent a postoperative MRI. Fourteen of the 53 were excluded owing to revision status or additional procedures. The final study population included 39 patients (23 female patients and 16 male patients), with an average patient age of 31.7 ± 11.4 years and an average body mass index of 23.3 ± 2.9. There were 3 (7.5%) capsular defects, and the intraclass correlation coefficient (ICC) was 0.82. The operative hip capsule was significantly thicker in the zone of capsulotomy, and subsequent repair as compared with the unaffected, contralateral hip capsule (5.0 ± 1.2 mm vs 4.6 ± 1.4 mm; P = .02), ICC 0.83. Additionally, males had thicker hip capsules as compared with their female counterparts, on the operative side (5.4 ± 1.1 mm vs 4.5 ± 1.2 mm; P = .02) and the nonoperative side (4.8 ± 1.6 mm vs 4.1 ± 0.9 mm; P = .08). CONCLUSIONS: In a subset of symptomatic patients after hip arthroscopy for FAI, the majority (92.5%) of the repaired hip capsules remained closed at greater than 1 year of follow-up. The hip capsule adjacent to the capsulotomy and subsequent repair is thickened compared with the same location on the contralateral, nonoperative hip. Aside from gender, patient-related and FAI-related factors do not correlate with capsular thickness nor do they seem to correlate with the propensity to develop a capsular defect. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Radiographic Signs of Femoroacetabular Impingement Are Associated With Decreased Pelvic Incidence.

PURPOSE: To investigate the relation between cam, acetabular version, and pelvic incidence. METHODS: This was a retrospective analysis of 65 patients with symptomatic hip pain and radiographic signs of femoroacetabular impingement (FAI). Twenty-seven patients were used as a control. All patients received a CT scan of the pelvis that included the sacral endplate. Alpha angle, acetabular version, and pelvic incidence (PI) were measured on 2D CT. Patients were then assigned to 1 of 4 groups: control, cam (alpha angle > 55°, version > 15°), retroverted (alpha angle < 55°, version < 15°), or mixed (alpha angle > 55°, version < 15°). RESULTS: The PI in mixed-type FAI was 46.7° ± 3.7°, which showed a statistically significant decrease from the PI of the control group, 56.1° ± 4.4° (P = .01). The PI for cam-only deformity was 50.8° ± 4.6°, and the PI for retroverted-only deformity was 51.0° ± 4.6°. Neither was statistically different from the control. CONCLUSIONS: This study suggests that mixed-type FAI may develop as a response to decreased PI. This result is consistent with previous reports showing decreased PI associated with cam and retroversion deformities. Although the cause of FAI remains controversial, the potential impact of sagittal balance of the pelvis, and specifically, decreased PI, should not be ignored. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Capsulotomy Size Affects Hip Joint Kinematic Stability.

PURPOSE: To evaluate the effect of capsulotomy size and subsequent repair on the biomechanical stability of hip joint kinematics through external rotation of a cadaveric hip in neutral flexion. METHODS: Eight fresh-frozen cadaveric hip specimens were used in this study. Each hip was tested under torsional loads of 6 N·m applied by a servohydraulic frame and transmitted by a pulley system. The test conditions were (1) neutral flexion with the capsule intact, (2) neutral flexion with a 4-cm interportal capsulotomy, (3) neutral flexion with a 6-cm capsulotomy, and (4) neutral flexion with capsulotomy repair. Soft tissue was retained during all interventions. Measures indicating joint kinematics (range of motion [ROM], hysteresis area [HA], and neutral zone [NZ]) were obtained for each condition. RESULTS: For all hip specimens, the average ROM, HA, and NZ were calculated relative to the intact capsular state (100%) and expressed in terms of percentage (± SD). The findings for ROM were as follows: intact, 100%; 4 cm, 107.42% ± 5.69%; 6 cm, 113.40% ± 7.92%; and repair, 99.78% ± 3.77%. The findings for HA were as follows: intact, 100%; 4 cm, 108.30% ± 9.30%; 6 cm, 115.30% ± 13.92%; and repair, 99.47% ± 4.12%. The findings for NZ were as follows: intact, 100%; 4 cm, 139.61% ± 62.35%; 6 cm, 169.25% ± 78.19%; and repair, 132.03% ± 64.38%. Statistically significant differences in ROM existed between the intact and 4-cm conditions (P = .039), the intact and 6-cm conditions (P < .0001), the 4-cm and repair conditions (P = .033), and the 6-cm and repair conditions (P < .0001). There was no statistically significant difference between the intact and repair conditions (P > .99) or between the 4- and 6-cm conditions (P = .126). CONCLUSIONS: Under laboratory-based conditions, larger-sized capsulotomies were accompanied by increases in all 3 measures of joint mobility: ROM, HA, and NZ at time zero. Complete capsular closure effectively restored these measures when compared with the intact condition. CLINICAL RELEVANCE: Cadaveric models consisting of the hip joint with surrounding soft tissue were used under laboratory testing conditions to investigate potential iatrogenic joint instability resulting from expansive capsulotomies, showing that complete capsular closure leads to reconstitution of original joint stability properties at time zero.

Radiographic Comparison of Anterior Acetabular Rim Morphology Between Pincer Femoroacetabular Impingement and Control.

PURPOSE: To define and compare 3 new parameters (anterior rim angle [ARA], anterior wall angle [AWA], and anterior margin ratio [AMR]), in addition to the lateral center-edge angle of Wiberg and the Tönnis angle, for measuring pincer-type femoroacetabular impingement (FAI) in an asymptomatic versus symptomatic FAI population. METHODS: We reviewed anteroposterior pelvis radiographs of patients verified to have no hip complaints between December 2009 and December 2011. We also reviewed anteroposterior pelvis radiographs of patients who underwent a rim-trimming procedure for pincer FAI between December 2010 and December 2011. Patients aged older than 65 years or younger than 18 years were excluded. Radiographs with a Tönnis grade of 2 or greater were also excluded. For the group of patients with symptomatic hip impingement, radiographs that did not have a crossover sign were excluded. The 2 cohorts were matched for age, sex, and body mass index. Measurements included the Tönnis angle, lateral center-edge angle of Wiberg, ARA, AWA, and AMR. These measurements were compared between the groups. RESULTS: Seventy-two asymptomatic hips were measured. There were 44 female patients (61%) and 28 male patients (39%), aged 25 to 51 years, in the asymptomatic group. The mean ARA was 88.91° ± 8.06°, the mean AWA was 34.89° ± 8.09°, and the mean AMR was 0.49 ± 0.15. Seventy-two symptomatic hips were measured. There were 40 female patients (56%) and 32 male patients (44%), aged 27 to 58 years, in the symptomatic group. The mean ARA was 82.98° ± 10.82°, the mean AWA was 39.11° ± 9.00°, and the mean AMR was 0.56 ± 0.14. The mean difference in the ARA between asymptomatic patients and symptomatic patients was 5.92° (P = .0001). The mean difference in the AWA was 4.22° (P = .0019). The mean difference in the AMR was 0.07 (P = .0039). CONCLUSIONS: Our study provides information on several measurements within an asymptomatic cohort and a symptomatic cohort. Although we found statistically significant differences between the 2 populations, the clinical significance remains unknown. We recommend using this asymptomatic population as a guideline for limits on resection of the anterior acetabular rim. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Quantification and correlation of hip capsular volume to demographic and radiographic predictors.

PURPOSE: The purpose of this study was to develop a novel method to quantify hip capsular volume in patients undergoing hip arthroscopic surgery, utilizing magnetic resonance arthrogram (MRA) and to determine whether there are demographic or radiological factors that are associated with capsular volume. METHODS: A retrospective review was performed from 2006 to 2014 of consecutive patients who presented with hip pain and received a hip MRA and plain radiographs. All patients were suspected of soft tissue injury due to underlying femoroacetabular impingement (FAI). A novel technique using Osirix MD for the quantification of capsular and femoral head volumes was described. RESULTS: Ninety-seven patients met the study criteria and were included for analysis. The average total capsular volume (including the femoral head) measured 79.89 ± 20.35 cm(3), average femoral head volume 46.68 ± 12.32 cm(3), and average true capsular volume measured 33.20 ± 12.58 cm(3). Average total capsular:femoral head volume ratio was 1.74 ± 0.27. Significant differences were seen between genders for total capsular volume (P < 0.01), femoral head volume (P < 0.01), and true capsular volume (P < 0.01). Total capsular volume:femoral head ratio was greater for females, but was not statistically significant (n.s.). Femoral head volume significantly correlated with alpha angle (P < 0.01), height (P < 0.01), BMI (P < 0.01), BMI (P = 0.02), and age (P < 0.01). Total capsular volume significantly correlated with height (P < 0.01), BMI (P = 0.01), and age (P < 0.01). Age was also correlated with true capsular volume (P = 0.011). No significant differences in capsular volumes were found between normal and abnormal radiographic measurements. CONCLUSION: The current study describes a reproducible radiographic measurement for hip capsule volumes from MRAs. Only gender was predictive of total capsular volume, femoral head volume, and true capsular volume. There were no macroscopic anatomical differences evident on MRA. This method showed good intra- and inter-observer reliability and can aid in future research regarding hip capsule volumes. This novel technique may potentially allow clinicians a readily available and reliable method to detect large and redundant capsules, a possible predisposition for hip micro-instability. LEVEL OF EVIDENCE: Retrospective case series, Level IV.

The False-Profile View May Be Used to Identify Cam Morphology.

PURPOSE: To identify the accuracy of measuring the alpha angle on the false-profile, anteroposterior (AP), and 90° Dunn lateral views of the hip as compared with computed tomography (CT) scan findings. METHODS: Forty patients were needed to have power greater than 80%. Forty-five consecutive patients undergoing hip arthroscopy were retrospectively reviewed with preoperative radial oblique CT reformatted scans and plain radiographs. Alpha angles were measured on plain radiographs (AP, 90° Dunn lateral, and false profile) and CT reformatted views. Abnormal alpha angles were considered greater than 50.5°. Two orthopaedic surgeons independently measured the images, and the results were compared between imaging modalities. RESULTS: The false-profile view was 60% sensitive and 89.0% specific for diagnosing cam deformities of the hip. All radiographs combined were 86% sensitive and 75% specific for diagnosing cam deformities. The false-profile view most strongly correlated with the 2-o'clock (R = 0.746, P = .001) and 3-o'clock (R = 0.698, P < .0001) positions. An intraclass correlation coefficient of 0.81 was found for measurement of the alpha angle on the false-profile view. CONCLUSIONS: This study has proved that the false-profile view effectively characterizes cam deformity, especially anterior deformity at the 3-o'clock position. Measuring the alpha angle on the false-profile view appears to be reproducible. The false-profile view along with standing AP pelvis and 90° Dunn lateral views of the hip comprises a good screening radiographic series for patients presenting with symptoms of femoroacetabular impingement. LEVEL OF EVIDENCE: Level III, diagnostic study.

Prevalence of Femoroacetabular Impingement Imaging Findings in Asymptomatic Volunteers: A Systematic Review.

PURPOSE: The aim of this study was to determine the prevalence of radiographic findings suggestive of femoroacetabular impingement (FAI) in asymptomatic individuals. METHODS: A systematic review was performed using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Studies reporting radiographic, computed tomographic, or magnetic resonance imaging (MRI) findings that were suggestive of FAI in asymptomatic volunteers were included. Cam, pincer, and combined pathologic conditions were investigated. RESULTS: We identified 26 studies for inclusion, comprising 2,114 asymptomatic hips (57.2% men; 42.8% women). The mean participant age was 25.3 ± 1.5 years. The mean alpha angle in asymptomatic hips was 54.1° ± 5.1°. The prevalence of an asymptomatic cam deformity was 37% (range, 7% to 100% between studies)-54.8% in athletes versus 23.1% in the general population. Of the 17 studies that measured alpha angles, 9 used MRI and 9 used radiography (1 study used both). The mean lateral and anterior center edge angles (CEAs) were 31.2° and 30°, respectively. The prevalence of asymptomatic hips with pincer deformity was 67% (range 61% to 76% between studies). Pincer deformity was poorly defined (4 studies [15%]; focal anterior overcoverage, acetabular retroversion, abnormal CEA or acetabular index, coxa profunda, acetabular protrusio, ischial spine sign, crossover sign, and posterior wall sign). Only 7 studies reported on labral injury, which was found on MRI without intra-articular contrast in 68.1% of hips. CONCLUSIONS: FAI morphologic features and labral injuries are common in asymptomatic patients. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging. LEVEL OF EVIDENCE: Level IV, systematic review if Level II-IV studies.

Effect of interference screw depth on fixation strength in biceps tenodesis.

PURPOSE: The purpose of this study was to assess the biomechanical performance of the long head of the biceps tenodesis with an interference screw with respect to screw depth. METHODS: Twenty-one human cadaveric shoulders were randomized into 3 treatment groups (7 each): interference screw placed flush to the humeral cortex, 50% proud, or fully recessed. Bone density was determined, and subpectoral biceps tenodesis was performed with 8 × 12 mm Bio-Tenodesis screws (Arthrex, Naples, FL). Each construct was cyclically loaded from 5 to 70 N for 500 cycles at 1 Hz and then pulled to failure at 1 mm/s. Relative actuator displacement was calculated from cyclic testing. Maximum load, elongation, linear stiffness, and failure mode were recorded from pull-to-failure testing. Because of numerous failures during cyclic testing, the final load data from the fully recessed group were not statistically analyzed. The remaining groups were compared by use of a 2-tailed, Student unpaired t test and χ(2) analysis. RESULTS: There was no significant difference in displacement among groups during cyclic testing. Five specimens in the recessed group failed during cyclic testing, whereas 2 specimens and 0 specimens failed in the proud and flush groups, respectively. The maximum loads sustained were 281.6 ± 77.8 N, 184.5 ± 56.3 N, and 209.1 ± 57.0 N for the flush group, 50% proud group, and recessed group (in those specimens surviving cyclical loading), respectively. CONCLUSIONS: Placement of a Bio-Tenodesis screw flush to the humeral cortex is preferred for maximum fixation strength in subpectoral biceps tenodesis. A screw placed to 50% depth may be effective in the laboratory setting, but recessed placement is more variable and requires additional fixation. The fully recessed group resulted in 5 of 7 failures during cyclical loading, with no specimens failing in the flush group. CLINICAL RELEVANCE: This study shows the importance of determining the optimal depth of interference screw placement during biceps tenodesis to obtain optimal biomechanical performance and reduce the risk of fixation failure.

The high failure rate of biologic resurfacing of the glenoid in young patients with glenohumeral arthritis.

BACKGROUND: The current study evaluated the outcomes of biologic resurfacing of the glenoid using a lateral meniscus allograft or human acellular dermal tissue matrix at intermediate-term follow-up. METHODS: Forty-five patients (mean age, 42.2 years) underwent biologic resurfacing of the glenoid, and 41 were available for follow-up at a mean of 2.8 years. Lateral meniscal allograft resurfacing was used in 31 patients and human acellular dermal tissue matrix interposition in 10. Postoperative range of motion and clinical outcomes were assessed at the final follow-up. RESULTS: The overall clinical failure rate was 51.2%. The lateral meniscal allograft cohort had a failure rate of 45.2%, with a mean time to failure of 3.4 years. Human acellular dermal tissue matrix interposition had a failure rate of 70.0%, with a mean time to failure of 2.2 years. Overall, significant improvements were seen compared with baseline with respect to the visual analog pain score (3.0 vs. 6.3), American Shoulder and Elbow Surgeons score (62.0 vs. 36.8), and Simple Shoulder Test score (7.0 vs. 4.0). Significant improvements were seen for forward elevation (106° to 138°) and external rotation (31° to 51°). CONCLUSION: Despite significant improvements compared with baseline values, biologic resurfacing of the glenoid resulted in a high rate of clinical failure at intermediate follow-up. Our results suggest that biologic resurfacing of the glenoid may have a minimal and as yet undefined role in the management of glenohumeral arthritis in the young active patient over more traditional methods of hemiarthroplasty or total shoulder arthroplasty.

Role of the superior labrum after biceps tenodesis in glenohumeral stability.

BACKGROUND: Little is known about the role that a torn superior labrum (SLAP) plays in glenohumeral stability after biceps tenodesis. This biomechanical study evaluated the contribution of a type II SLAP lesion to glenohumeral translation in the presence of biceps tenodesis. The authors hypothesize that subsequent to biceps tenodesis, a torn superior labrum does not affect glenohumeral stability and therefore does not require anatomic repair in an overhead throwing athlete. METHODS: Baseline anterior, posterior, and abduction and maximal external rotation glenohumeral translation data were collected from 20 cadaveric shoulders. Translation testing was repeated after the creation of anterior (n = 10) and posterior (n = 10) type II SLAP lesions. Translation re-evaluation after biceps tenodesis was performed for each specimen. Finally, anatomic SLAP lesion repair and testing were performed. RESULTS: Anterior and posterior SLAP lesions led to significant increases in glenohumeral translation in all directions (P < .0125). Biceps tenodesis showed no significance in stability compared with SLAP alone (P > .0125). Arthroscopic repair of anterior SLAP lesions did not restore anterior translation compared with the baseline state (P = .0011) but did restore posterior (P = .823) and abduction and maximal external rotation (P = .806) translations. Repair of posterior SLAP lesions demonstrated no statistical difference compared with the baseline state (P > .0125). CONCLUSIONS: With no detrimental effect on glenohumeral stability in the presence of a SLAP lesion, biceps tenodesis may be considered a valid primary or revision surgery for patients suffering from symptomatic type II SLAP tears. However, biceps tenodesis should be considered with caution as the primary treatment of SLAP lesions in overhead throwing athletes secondary to its inability to completely restore translational stability.