Static and dynamic mechanical causes of hip pain

Structure, composition and anisotropic swelling of the bovine acetabular labrum

The fibro-cartilaginous labrum surrounds the acetabular rim and is important for hip joint stability and sealing. Sealing may be enhanced by swelling pressure within the normal labrum. Swelling of the degenerated or torn labrum might occur and potentially contribute to the development of osteoarthritis, through altered load transmission. This study aimed to characterize the three-dimensional swelling behaviour, the collagen fiber orientation and spatial proteoglycan distribution of the bovine acetabular labrum. Specimens were harvested from bovine donors (192-652 days, male, n = 6 donors). Structure was analyzed by scanning electron microscopy, histology, and dimethylmethylene blue assay. Specimen dimensions were measured before and after incubation in phosphate buffered saline to assess the swelling. Results showed that the articulating surface is composed of a collagen mesh network. Collagen fiber bundles showed a low degree of alignment close to the surface and were circumferentially aligned in the deep tissue. Proteoglycans were identified clustered between the collagen bundles. Glycosaminoglycan content was 10 x lower than that of cartilage (23.1 ± 6.4 compared to 299.5 ± 19.1 μg/mg dry weight) with minor regional differences. Specimens swelled significantly more in the orthogonal direction (swelling ratio 124.7 ± 10.2%) compared to the swelling parallel to the articulating surface (108.8 ± 6.1% and 102.8 ± 4.1%). In the deep tissue, swelling was also restricted in the main collagen fiber bundle direction (circumferentially), with a swelling ratio of 109.5 ± 4.0% in the main fiber bundle direction compared to 126.8 ± 7.3 % and 122.3 ± 5.8% radially. The findings demonstrate that the labrum shows anisotropic swelling properties, which reflect the anisotropy in the tissue structure and inter-fiber localisation of proteoglycans.

The Influence of Compensatory Pelvic Tilt on Patient-reported Outcome Measurements in FAI Patients Who Received Arthroscopic Treatment

OBJECTIVE

Pelvic compensation is common in femoroacetabular impingement (FAI) patients to reduce symptoms and increase range of motion. However, little attention was given to the postoperative clinical effect of pelvic compensation. Therefore, this study aims to compare the outcomes between pelvic compensation and normal pelvic position in femoroacetabular impingement (FAI) patients after hip arthroscopy.

METHODS

The retrospective study was conducted from January 2019 to June 2022, recruited consecutive patients who were diagnosed with FAI and received subsequent arthroscopic treatment. All patients completed an X-ray in the anterior-posterior standing position before and 4 weeks after surgery. Patients with pelvic compensation were compared with those who did not. Functional outcomes included hip disability and osteoarthritis outcome score (HOOS), modified Harris (mHHS) score, and lower-extremity activity scale (LEAS). Secondary outcomes included the EuroQol Five Dimensions Questionnaire (EQ-5D) and patient satisfaction. The intraclass correlation coefficient (ICC) was used to analyze interobserver and intraobserver reliability.

RESULTS

Ninety patients with a mean age of 39.40 years were included in the study. No significant compensation changes were noted within groups after the elimination of impingement. The functional scores showed no significant difference between groups (p(HOOS) = 0.352, p(mHHS) = 0.183, p(LEAS) = 0.865). The EQ-5D revealed statistically better performance in usual activities in the compensatory group (p = 0.044). There are no significant between-group differences in patients' satisfaction evaluations.

CONCLUSION

As assessed by Patient-Reported Outcome Measures (PROMs), patients with compensatory pelvic tilt demonstrated similar clinical outcomes without extra adverse events to patients with normal pelvic positioning in short-term follow-ups. Furthermore, compensatory pelvic tilt did not significantly enhance the range of motion or functional outcome at short-term follow-ups.

Does Increased Femoral Anteversion Can Cause Hip Abductor Muscle Weakness?

BACKGROUND

Increased femoral anteversion (IFA) causes functional problems (i.e., tripping, frequently falling, and fatigue) by affecting the pelvis and lower extremity biomechanics. In the frontal plane, increased contralateral pelvic drop and ipsilateral hip adduction, which are mainly considered deteriorated hip abductor muscle mechanisms, are associated with hip and knee injuries.

AIMS

The aim of this study was to examine the effects of femoral anteversion on hip abductor weakness and frontal plane pelvis-hip biomechanics during walking.

METHODS

The study included nine subjects with increased femoral anteversion and a control group of eleven subjects. Maximum isometric voluntary contraction (MIVC) values of the hip abductor muscles were measured with a handheld dynamometer. Three-dimensional gait analysis was performed for kinetic, kinematic, and temporo-spatial gait parameters. Non-parametric tests were used for statistical analysis (p < 0.05).

RESULTS

There was no significant difference found between the MIVC values of the IFA and control groups (p = 0.14). Moreover, no significant difference was determined between the ipsilateral peak hip adduction (p = 0.088) and contralateral pelvic drop (p = 0.149) in the stance phase. Additionally, there was no correlation between the peak hip adduction angle in the stance phase and normalized MIVC values in the IFA group (r = -0.198, p = 0.44), or in the control group (r = -0.174, p = 0.55). The deviations of pelvic rotation (p = 0.022), hip internal rotation (p = 0.003), and internal foot progression (p = 0.022), were found to be higher in the IFA group than in the controls.

CONCLUSIONS

IFA may not be associated with hip abductor muscle weakness, and it may not lead to the hip adduction and pelvic depression that can be seen in hip abductor weakness. Increased pelvic rotation and internal hip rotation during walking might be considered as a compensation for the femoral head-acetabulum alignment mechanism in the frontal plane.

Dysplastic hips demonstrate increased joint translation at higher body mass index

OBJECTIVE

To determine which radiographic measures used to define the severity of hip dysplasia are associated with hip joint translation and to investigate relationships between position, body mass index, and joint translation.

MATERIALS AND METHODS

This is a cross-sectional retrospective study evaluating 10 validated radiographic measures of dysplasia on weight-bearing AP pelvis and supine 45-degree bilateral Dunn radiographs of 93 young adults with symptomatic hip dysplasia presenting to a single academic institution between October 2016 and May 2019. We determined the difference between standing and supine measurements for each hip and the correlation of each measure with the patient's body mass index.

RESULTS

Femoral head extrusion index was 2.49% lower on supine X-ray (p = 0.0020). Patients with higher body mass index had higher center gap distance (p = 0.0274), femoral head extrusion (p = 0.0170), and femoral head lateralization (p = 0.0028) when standing. They also had higher Tönnis angle (p_standing = 0.0076, p_supine = 0.0121) and lower lateral center-edge angle (p_standing = 0.0196, p_supine = 0.0410) in both positions. The difference in femoral head lateralization between standing and supine positions increased with higher body mass index (p = 0.0081).

CONCLUSION

Translation of the hip joint with position change is demonstrated by decreased femoral head extrusion index on supine X-ray. Patients with higher body mass index had more dysplastic hips, as measured by five of six radiographic outcomes of dysplasia, and experienced more translation with weight-bearing, reflected by increased femoral head lateralization.

Open and arthroscopic management of femoroacetabular impingement: a review of current concepts

Femoroacetabular impingement (FAI) is a common femoral and/or acetabular abnormality that can cause progressive damage to the hip and osteoarthritis. FAI can be the result of femoral head/neck overgrowth, acetabular overgrowth or both femoral and acetabular abnormalities, resulting in a loss of native hip biomechanics and pain upon hip flexion and rotation. Radiographic evidence can include loss of sphericity of the femoral neck (cam impingement) and/or acetabular retroversion with focal or global overcoverage (pincer impingement). Operative intervention is indicated in symptomatic patients after failed conservative management with radiographic evidence of impingement and minimal arthritic changes of the hip, with the goal of restoring normal hip biomechanics and reducing pain. This is done by correcting the femoral head-neck relationship to the acetabulum through femoral and/or acetabular osteoplasty and treatment of concomitant hip pathology. In pincer impingement cases with small lunate surfaces, reverse periacetabular osteotomy is indicated as acetabular osteoplasty can decrease an already small articular surface. While surgical dislocation is regarded as the traditional gold standard, hip arthroscopy has become widely utilized in recent years. Studies comparing both open surgery and arthroscopy have shown comparable long-term pain reduction and improvements in clinical measures of hip function, as well as similar conversion rates to total hip arthroplasty. However, arthroscopy has trended toward earlier improvement, quicker recovery and faster return to sports. The purpose of this study was to review the recent literature on open and arthroscopic management of FAI.

Correlation of femoral version measurements between computed tomography and magnetic resonance imaging studies in patients presenting with a femoroacetabular impingement-related complaint

Computed tomography (CT) is considered the gold standard for femoral version measurement. However, recent data have shown magnetic resonance imaging (MRI) as another modality to measure femoral version. This study aimed to correlate MRI and CT femoral version measurements in patients presenting with a femoroacetabular impingement (FAI)-related complaint. Patients (18-35 years old) who presented to the hip preservation clinic and radiology department with a suspected FAI diagnosis from 26 December 2018 to 4 March 2020 were included. All patients had a CT and MRI of the hip, with images including both hips and knees, as per our institution's protocol for possible hip preservation surgery. Patients were excluded if they were missing views of the knees, or if they had a history or imaging appearance of any condition affecting femoral version at the femoral head (e.g. slipped capital femoral epiphysis). Femoral version was measured by three reviewers. Fifty-eight patients were included, and 36 (62%) were female. Femoral version averaged 6.1° ± 11.8° on CT and 6.5° ± 10.8° on MRI. A strong positive correlation was reported between the two imaging modalities (r: 0.81; P < 0.001). Inter-rater reliability among the three reviewers was excellent and statistically significant for measurements on both MRI [intraclass correlation coefficient (ICC): 0.95; 95% CI: 0.85, 0.99; P < 0.001] and CT (ICC: 0.97; 95% CI: 0.92, 0.99; P < 0.001). Our finding suggests that MRI is a sufficient method for measuring femoral version to determine disease etiology and treatment progression. To avoid exposing patients to ionizing radiation, physicians should not obtain CT scans to evaluate femoral version.

Lower limb bone geometry in adult individuals with X-linked hypophosphatemia: an observational study

We assessed lower-limb geometry in adults with X-linked hypophosphatemia (XLH) and controls. We found large differences in multiple measures including femoral and tibial torsion, bowing and cross-sectional area and acetabular version and coverage which may contribute to clinical problems such as osteoarthritis, fractures and altered gait common in XLH.

PURPOSE

Individuals with X-linked hypophosphatemia (XLH) are at risk of lower-limb deformities and early onset of osteoarthritis. These two factors may be linked, as altered biomechanics is a risk factor for osteoarthritis. This exploratory evaluation aims at providing clues and concepts for this association to facilitate future larger-scale and longitudinal studies on that aspect.

METHODS

For this observational study, 13 patients with XLH, aged 18-65 years (6 female), were compared with sex-, age- and weight-matched healthy individuals at a single German research centre. Femoral and hip joint geometry, including femoral and tibial torsion and femoral and tibial shaft bowing, bone cross-sectional area (CSA) and acetabular version and coverage were measured from magnetic resonance imaging (MRI) scans.

RESULTS

Total femoral torsion was 29° lower in individuals with XLH than in controls (p < 0.001), mainly resulting from lower intertrochanteric torsion (ITT) (p < 0.001). Femoral lateral and frontal bowing, tibial frontal bowing, mechanical axis, femoral mechanical-anatomical angle, acetabular version and acetabular coverage were all greater and tibial torsion lower in individuals with XLH as compared to controls (all p < 0.05). Greater femoral total and marrow cavity CSA, greater tibial marrow cavity CSA and lower cortical CSA were observed in XLH (all p < 0.05).

DISCUSSION

We observed large differences in clinically relevant measures of tibia and particularly femur bone geometry in individuals with XLH compared to controls. These differences may plausibly contribute to clinical manifestations of XLH such as early-onset osteoarthritis, pseudofractures and altered gait and therefore should be considered when planning corrective surgeries.

Hip Preservation Surgery in Osteoarthritis Prevention: Potential Benefits of the Radiographic Angular Correction

Objective: The aim of the study is to describe the morphology associated with the development of osteoarthritis (OA) in three different age groups. These data will contribute to defining the morphology associated with early and late hip OA. Methods: We studied 400 hips in 377 patients who had undergone primary THA due to idiopathic OA. Three groups were compared: group 1 (n = 147), younger patients, aged up to 60 years; group 2 (n = 155), patients aged between 61 and 74 years; and group 3 (n = 98), aged 75 or over. Five independent researchers measured the hip angles and the mean values were used to build a database. Results: No differences between groups in sex distribution and BMI were detected. Less coverage of the head (extrusion index), higher Tönnis angle, lower Wiberg and alpha angles characterized early OA hips. These differences increased with age, being greater between group 2 and group 3 (p < 0.01). However, significant differences were still present in the comparison between group 1 and group 2 (p < 0.01)). No differences were detected between group 2 and group 3. Conclusion: Elevated acetabular angle, head extrusion and decreased Wiberg angle characterize hip osteoarthritis at younger ages and should be the focus of hip preservation surgery in terms of osteoarthritis prevention. Pincer-type FAI (higher Wiberg and lower Tönnis angle) and higher alpha angle (CAM) are correlated with the development of later OA. These results shed doubt on applying the hip preservation surgery concept in terms of osteoarthritis prevention in FAI, especially in Pincer-type FAI patients.

Risk factors for early symptomatic femoroacetabular impingement following in situ fixation of slipped capital femoral epiphysis

In situ fixation of slipped capital femoral epiphysis (SCFE) results in residual deformity that can cause femoroacetabular impingement (FAI). It is unknown what factors could help differentiate patients who are more likely to become symptomatic. We performed a retrospective review of 55 hips treated with in situ pinning for SCFE and subsequent secondary deformity correction procedure for symptomatic FAI and compared them to 39 asymptomatic hips with SCFE deformity using multivariable analysis. Case patients were slightly older than controls (12.6 vs 11.3 years, p = 0.0002) but had similar BMI. The mean epiphyseal-diaphyseal angle was 56° in cases versus 44° in controls (p = 0.0019). Cases were significantly more likely to have obligate external rotation with hip flexion, external foot progression, flexion <90°, antalgic limp, and Trendelenburg lurch. On radiographs, most cases had a head-neck offset ≤0 mm, a distinct metaphyseal corner prominence, acetabular retroversion, and an alpha angle ≥60°. Most controls also had head-neck offset ≤0 mm. Pre-pinning, older age (OR = 1.98 per year, p = 0.0016) and initial epiphyseal-diaphyseal angle (OR = 1.04 per degree, p = 0.018) significantly increased the odds of having symptomatic FAI. Post-pinning, external foot progression increased the odds of symptomatic FAI by 10.48 (p = 0.017), and an alpha angle ≥60° resulted in 11.4 times higher odds of symptomatic FAI (p = 0.011). The linear correlation between epiphyseal-diaphyseal and alpha angle was poor (r = 0.28). Older age and initial epiphyseal-diaphyseal pre-pinning mildly increased the odds of eventual symptomatic FAI. This information can help the surgeon to predict which patients may develop symptomatic FAI.

Open MRI assessment of anterior femoroacetabular clearance in active and passive impingement-provoking postures

Aims

Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement.

Methods

We recruited nine participants with cam and/or pincer morphologies and with pain, 13 participants with cam and/or pincer morphologies and without pain, and 11 controls from a population-based cohort. We scanned hips in active squatting and passive sitting flexion, adduction, and internal rotation using open MRI and quantified anterior femoroacetabular clearance using the β angle.

Results

In squatting, we found significantly decreased anterior femoroacetabular clearance in painful hips with cam and/or pincer morphologies (mean -11.3° (SD 19.2°)) compared to pain-free hips with cam and/or pincer morphologies (mean 8.5° (SD 14.6°); p = 0.022) and controls (mean 18.6° (SD 8.5°); p < 0.001). In sitting flexion, adduction, and internal rotation, we found significantly decreased anterior clearance in both painful (mean -15.2° (SD 15.3°); p = 0.002) and painfree hips (mean -4.7° (SD 13°); p = 0.010) with cam and/pincer morphologies compared to the controls (mean 7.1° (SD 5.9°)).

Conclusion

Our results support the anterior femoroacetabular impingement pathomechanism in hips with cam and/or pincer morphologies and highlight the effect of posture on this pathomechanism.

Cite this article: Bone Jt Open 2021;2(11):988–996.

Open MRI validation of a hip model driven with subject-specific motion capture data in predicting anterior femoroacetabular clearance

BACKGROUND

Cam and/or pincer morphologies (CPM) are potential precursors to hip osteoarthritis (OA) and important contributors to non-arthritic hip pain. However, only some CPM hips develop OA and/or pain, and it is not clear why. Anterior impingement between the femoral head/neck contour and acetabular rim during motion is a proposed pathomechanism. Understanding how activity and deformity combine to produce impingement may shed light on the causes of hip degeneration/pain. The objective of this study was to determine the accuracy of a subject-specific hip model driven by subject-specific motion data in predicting anterior impingement.

METHODS

We recruited 22 participants with CPM (both with and without pain) and 11 controls. We collected subject-specific 3D kinematics during squatting and sitting flexion, adduction, and internal rotation (FADIR) (an active and a passive maneuver, respectively, proposed to provoke impingement). We then developed 3D subject-specific hip models from supine 3T hip MRI scans that predicted the beta angle (a measure of anterior femoroacetabular clearance) for each frame of acquired kinematics. To assess the accuracy of these predictions, we measured the beta angle directly in the final position of squatting and sitting FADIR using open MRI scans. We selected the frame of motion data matching the static imaged posture using the least-squares error in hip angles. Model accuracy for each subject was calculated as the absolute error between the open MRI measure of beta and the model prediction of beta at the matched time frame. To make the final model accuracy independent of goodness of match between open MRI position and motion data, a threshold was set for least-squares error in hip angles, and only participants that were below this threshold were considered in the final model accuracy calculation, yielding results from 10 participants for squatting and 7 participants for sitting FADIR.

RESULTS

For squatting and sitting FADIR, we found an accuracy of 1.1°(0.8°) and 1.3°(mean (SD), and root mean squared error, respectively) and 0.5°(0.3°) and 0.6°, respectively.

CONCLUSION

This subject-specific hip model predicts anterior femoroacetabular clearance with an accuracy of about 1°, making it useful to predict anterior impingement during activities measured with motion analysis.

Arthroscopic Hip Surgery versus Conservative Therapy on Femoroacetabular Impingement Syndrome: A Meta-Analysis of RCTs

To determine the outcome and differences between arthroscopic hip surgery and conservative therapy in patients suffering from femoroacetabular impingement syndrome, we searched articles from PubMed, Embase, Cochrane, Web of Science and Clinicaltrials.gov using a Boolean search algorithm. Only randomized controlled trials comparing arthroscopic hip surgery and conservative therapy were included in this meta‐analysis of femoroacetabular impingement syndrome management. Two authors determined eligibility, extracted the needed data and assessed the risk of bias of eligible studies independently. Then we meta‐analyzed three articles to assess pooled estimate size (ES) and 95% confidence interval for Hip Outcome Score of activities of daily living (HOS ADL subscale), Hip Outcome Score sport (HOS sports subscale) and International Hip Outcome Tool (iHOT‐33) analyses were performed by using STATA version 14.0 MP (STATA, College Station, TX, USA) with the principal summary measures are mean between group difference, sample size, and standard deviation. We collected 52 articles in total after removing duplicates and screened by titles and abstracts. A total of three RCTs were included finally. There was definite evidence of additional benefit of arthroscopic hip surgery against conservative therapy in the field of improving quality of life (three trials, 575 participants, ES = 2.109, 95% CI: 1.373 to 2.845, I² = 42.8%, P = 0.000) and activity of daily living (two trials, 262 participants, ES = 9.220, 95% CI: 5.931 to 12.508, I² = 16.5%, P = 0.000). However, no significant difference could be seen in sports function improvement (two trials, ES = 7.562, 95% CI: −2.957 to 18.082, I² = 60.1%, P = 0.159). In conclusion, this meta‐analysis suggests that arthroscopic hip surgery provided essential benefit compared with conservative therapy in improving activity of daily living and quality of life.

Proximal Femoral Rotational Osteotomy for Symptomatic Femoral Retroversion : A Case Report

The Rotational osteotomy for femoral retroversion has been extremely rare despite the known association between femoral neck retroversion, hip pain, and osteoarthritis. Here, we describe a case of femoral neck retroversion for which proximal femoral rotation osteotomy. A 16-year-old boy with a past history of developmental dysplasia of the both hip treated conservatively presented with a complaint of pain in left hips. On physical examination, flexion of the left hip was limited to 90° with terminal pain. Internal rotation was also limited to 10°. Computed tomography (CT) showed -7.1° anteversion of the left femur. We performed rotational osteotomy to increase femoral anteversion because conservative treatment was not effective. The postoperative course was uneventful. At 12 postoperative months, his left hip pain was completely disappeared and femoral anteversion was 34° on CT scans. Retroversion of the femur is a distinct dynamic factor that should be considered in the evaluation of mechanical causes of hip pain. Restoring the normal rotational alignment of the hip resulted in cure of the impingement due to femoral retroversion. J. Med. Invest. 67 : 214-216, February, 2020.

Cam Osteochondroplasty for Femoroacetabular Impingement Increases Microinstability in Deep Flexion: A Cadaveric Study

PURPOSE

The purpose of this in vitro cadaveric study was to examine the contributions of each surgical stage during cam femoroacetabular impingement (FAI) surgery (i.e., intact-cam hip, T-capsulotomy, cam resection, and capsular repair) toward hip range of motion, translation, and microinstability.

METHODS

Twelve cadaveric cam hips were denuded to the capsule and mounted onto a robotic tester. The hips were positioned in several flexion positions-full extension, neutral (0°), 30° of flexion, and 90° of flexion-and performed internal-external rotations to 5 Nm of torque in each position. The hips underwent a series of surgical stages (T-capsulotomy, cam resection, and capsular repair) and were retested after each stage. Changes in range of motion, translation, and microinstability (overall translation normalized by femoral head radius) were measured after each stage.

RESULTS

Regarding range of motion, cam resection increased internal rotation at 90° of flexion (change in internal rotation = +6°, P = .001) but did not affect external rotation. Capsular repair restrained external rotation compared with the cam resection stage (change in external rotation = -8° to -4°, P ≤ .04). In terms of translation, the hip translated after cam resection at 90° of flexion in the medial-lateral plane (change in translation = +1.9 mm, P = .04) relative to the intact and capsulotomy stages. Regarding microinstability, capsulotomy increased microinstability in 30° of flexion (change in microinstability [Δ_M] = +0.05, P = .003), but microinstability did not further increase after cam resection. At 90° of flexion, microinstability did not increase after capsulotomy (Δ_M = +0.03, P = .2) but substantially increased after cam resection (Δ_M = +0.08, P = .03), accounting for a 31% change with respect to the intact stage.

CONCLUSIONS

Cam resection increased microinstability by 31% during deep hip flexion relative to the intact hip. This finding suggests that iatrogenic microinstability may be due to separation of the labral seal and resected contour of the femoral head.

CLINICAL RELEVANCE

Our in vitro study showed that, at time zero and prior to postoperative recovery, excessive motion after cam resection could disrupt the labral seal. Complete cam resection should be performed cautiously to avoid disruption of the labral seal and postoperative microinstability.

Reporting Clinical Significance in Hip Arthroscopy: Where Are We Now?

BACKGROUND

Although p values are standard for reporting statistical significance of patient-reported outcome measures (PROMs), the shift toward clinically important outcome values, including minimal clinically important difference (MCID) and substantial clinical benefit (SCB), necessitates re-evaluation of the current literature.

QUESTIONS/PURPOSES

We sought to answer two questions regarding studies on primary hip arthroscopy performed for the treatment of femoroacetabular impingement syndrome (FAIS). (1) Do such studies reporting statistical significance on common PROMs meet published MCID/SCB thresholds? (2) What proportion of such studies report both statistical and clinical significance?

METHODS

We identified four papers published in two journals defining MCID/SCB values on the modified Harris Hip Score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), Hip Outcome Score-Sport (HOS-Sport), international Hip Outcome Tool (iHOT-33), and its short version (iHOT-12) for different groups of FAIS patients undergoing hip arthroscopy. We reviewed these two journals from the dates of publication to the present to identify papers reporting changes in post-operative PROMs. The difference in pre- and post-operative scores on each PROM was calculated and compared to MCID/SCB thresholds.

RESULTS

Twelve studies were included. Ten studies (83%) evaluated mHHS (90% met MCID, 50% met SCB), seven (58%) evaluated HOS-ADL (100% met MCID/SCB) and HOS-Sport (100% met MCID, 57% met SCB), and one (8%) evaluated iHOT-33 (met MCID/SCB) and iHOT-12 (met MCID). Most studies met MCID and SCB at both 1- and 2-year timepoints. Of the studies evaluated, 50% reported clinical relevance.

CONCLUSIONS

Nearly all studies evaluated met MCID, while fewer met SCB. Only half discussed these clinical measures. It is proposed that all future studies report both statistical and clinical significance as standard best practice.

Pelvic morphology medial to the femoral head center predicts anterior coverage and range of motion after curved periacetabular osteotomy

This study observed anterior coverage extent after lateral rotation of the acetabulum, without anterior or posterior rotation, during curved periacetabular osteotomy by three-dimensional simulation, and determined if preoperative pelvic morphology affects postoperative anterior coverage and range of motion. Thirty patients scheduled for consecutive primary curved periacetabular osteotomy for developmental hip dysplasia at our hospital between 2016 and 2017 were included. Virtual acetabular osteotomies were performed to achieve a postoperative lateral center-edge angle of 30°. We measured anterior center-edge angles before curved periacetabular osteotomy through the medial one-third and one-quarter of the femoral head as an index reflecting the pelvic morphology medial to the femoral head center. The range of motion simulation was performed after virtual curved periacetabular osteotomy. Single linear regression analysis was performed to examine correlations between preoperative pelvic morphology parameters and anterior center-edge angles after virtual osteotomy. Furthermore, linear regression analysis was used to assess correlations between center-edge angles and simulated range of motions (P < .05). Anterior center-edge angle after virtual osteotomy was more strongly correlated with the anterior center-edge angle through the medial one-third (r = .92, P < .0001) and one-quarter (r = .84, P < .0001) of the femoral head. Flexion angle and internal rotation at 90° flexion showed significant correlations with anterior center-edge angle through the medial one-third (r = -.62, P = .0003; r = -.57, P = .001) and one-quarter (r = -.60, P = .0005; r = -.55, P = .002) of the femoral head and anterior center-edge angle after virtual osteotomy (r = -.67, P = .0005; r = -.62, P = .0003). Measuring preoperative parameters reflecting pelvic morphology enables surgeons to predict postoperative anterior coverage and range of motion in curved periacetabular osteotomy cases.

Hip-spine syndrome: rationale for ischiofemoral impingement, femoroacetabular impingement and abnormal femoral torsion leading to low back pain

The term 'hip-spine syndrome' was introduced in recognition of the frequent occurrence of concomitant symptoms at the hip and lumbar spine. Limitations in hip range of motion can result in abnormal lumbopelvic mechanics. Ischiofemoral impingement, femoroacetabular impingement and abnormal femoral torsion are increasingly linked to abnormal hip and spinopelvic biomechanics. The purpose of this narrative review is to explain the mechanism by which these three abnormal hip pathologies contribute to increased low back pain in patients without hip osteoarthritis. This paper presents a thorough rationale of the anatomical and biomechanical characteristics of the aforementioned hip pathologies, and how each contributes to premature coupling and limited hip flexion/extension. The future of hip and spine conservative and surgical management requires the implementation of a global hip-spine-pelvis-core approach to improve patient function and satisfaction.

Mirror Image Modeling of Acetabular Rim Thickness Differences in Patients With Unilateral Femoroacetabular Impingement Syndrome

Purpose

To use mirror imaging to identify the location and magnitude of difference in acetabular rim morphology between the symptomatic and unaffected acetabula in patients with symptomatic unilateral pincer-type or mixed femoroacetabular impingement syndrome (FAIS) using 1-dimensional models created with computed tomography (CT).

Methods

CT scans of bilateral hips in 33 patients diagnosed with unilateral pincer-type or mixed FAIS were obtained. Three-dimensional bilateral hip models were constructed, and the unaffected hemipelvis was superimposed onto the symptomatic side to compare acetabular thickness. Protrusion of the symptomatic side was recorded, and rim morphology was divided into clock face quadrants to analyze the location of greatest magnitude of difference between affected and unaffected acetabula. Analysis of the quadrants was performed using analysis of variance with post hoc Bonferroni correction.

Results

The study group consisted of more females (51.6%) than males, with an average age of 35.72 ± 7.8 years and an average body mass index of 24.3 ± 4.1 kg/m². Of the 33 hips included, 14 were isolated pincer-type FAIS and 19 were mixed. The average preoperative symptomatic side lateral center edge angle was 37.5° ± 7.2° compared with 29° ± 5.1° on the asymptomatic side (P = .001). The symptomatic acetabular rim was on average 0.43 ± 0.18 mm thicker than the corresponding location on the unaffected rim. When the acetabulum was divided into clock face quadrants, the 12 to 3 o'clock position showed the greatest difference between symptomatic and unaffected sides (0.55 ± 0.18 mm) compared with the 3 to 6 o'clock position (0.4 ± 0.28 mm; P = .006), 6 to 9 o'clock (0.34 ± 0.07 mm; P < .001), and 9 to 12 o'clock (0.38 ± 0.03; P = .001).

Conclusions

Patients with unilateral, symptomatic pincer-type or mixed FAIS show statistical differences in rim thickness between the affected and unaffected acetabula. Small changes in acetabular rim morphology on the order of ≤0.5 mm may be the difference between symptomatic FAIS and the unaffected hip.

Level of Evidence

IV, case series.

CrossFit-related hip and groin injuries: a case series

To provide descriptive data on injury presentation and treatment and to identify risk factors for requiring surgical treatment for athletes presenting with CrossFit-related hip and groin injuries. CrossFit-related injuries (n = 982) were identified within a single hospital system from 2010 to 2017, with 83 (8.5% of total) identified hip or groin injuries. Patient demographics, injury diagnosis, surgical procedure and rehabilitation were assessed. Independent predictors of requiring surgery were analyzed via multivariate logistic regression analysis. Patients with hip or groin injuries were more often female (hip injuries: 63%; all injuries: 50%; P < 0.001) with mean age 34.3 years (standard deviation 10.9). Median symptom duration was 4 months with 70% reporting insidious onset. Most common diagnoses were femoral-acetabular impingement syndrome (34%), hamstring strain (11%), non-specific hip/groin pain (imaging non-diagnostic) (11%), hernia (7%) and iliotibial band syndrome (6%). Most (90%) required physical therapy (median 2 months). Surgery occurred in 24% (n = 12 hip arthroscopy, n = 5 inguinal hernia repair, n = 3 total hip arthroplasty), with 100% return to sport after arthroscopy or hernia repair. The only predictor of surgery was complaint of primarily anterior hip/groin pain (82% surgical patients, 46% non-surgical) (odds ratio 5.78, 95% confidence interval 1.44–23.1; P = 0.005); age, sex, body mass index, symptom duration and symptom onset (insidious versus acute) were non-significant (P > 0.25). CrossFit athletes with hip and groin injuries often present with prolonged symptoms with insidious onset. Most patients require several months of physical therapy and approximately one quarter require surgery. Patients presenting with primarily anterior hip/groin pain are at increased risk for requiring surgery.

Improvement in Functional Outcome Scores Despite Persistent Pain With 1 Year of Nonsurgical Management for Acetabular Labral Tears With or Without Femoroacetabular Impingement

BACKGROUND

Acetabular labral tears are increasingly recognized as a source of hip pain in a younger active population. Given the significant focus on surgical intervention, there has been limited investigation on the nonsurgical management and natural history of such injuries.

HYPOTHESIS

Patients undergoing nonsurgical treatment for symptomatic acetabular labral tears experience functional improvement based on patient-reported outcome measures over the course of 1 year.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Seventy-one patients were identified who had acetabular labral injuries confirmed by magnetic resonance imaging or arthrography, received a minimum of 1 year of nonsurgical treatment, and completed baseline functional outcome questionnaires: modified Harris Hip Score (mHHS), Hip Outcome Score (HOS)-Activities of Daily Living, HOS-Sports, and iHOT-33 (International Hip Outcome Tool-33). Of these, 52 (73.2%) completed the minimum 1-year follow-up questionnaires. Chart review was conducted to obtain demographic information. Statistical significance ( P < .05) was determined by paired t test, independent samples t test, and chi-square test.

RESULTS

Twenty-two male and 30 female patients completed 1-year follow-up questionnaires. Mean ± SD follow-up time was 16.2 ± 3.1 months. The cohort had a mean age of 38.9 ± 9.3 years. Baseline radiographs demonstrated minimal arthritis (Tönnis grades 0-2). Mean alpha angle differed significantly between men and women at 52.9°± 8.6° and 46.3°± 8.5°, respectively. At 1-year follow-up, patients experienced a significant improvement in all 4 functional outcome measures (mHHS: 72.6 vs 81.8, HOS-Activities of Daily Living: 78.6 vs 86.4, HOS-Sports: 56.0 vs 71.1, iHOT-33: 47.5 vs 67.9). Patients with and without femoroacetabular impingement demonstrated a significant improvement in the mHHS. However, 48.1% reported no improvement in their pain; 69.2% were limited in their activities; and 40.4% were still considering surgery. Overall, 71.2% were satisfied with nonsurgical treatment.

CONCLUSION

Patients with symptomatic labral tears can experience functional improvement after a minimum 1 year of nonsurgical treatment in the presence and absence of femoroacetabular impingement. However, many report residual pain, alteration of their activities, and interest in surgery. This information is important when patients are counseled in the treatment options for this injury. Identifying the population that responds best to nonsurgical management and comparing outcomes with those undergoing surgical management should be the focus of future research. Longer-term follow-up may be necessary to reevaluate pain, function, and return to activities.

Hip Joint Torsional Loading Before and After Cam Femoroacetabular Impingement Surgery

BACKGROUND

Surgical management of cam femoroacetabular impingement (FAI) aims to preserve the native hip and restore joint function, although it is unclear how the capsulotomy, cam deformity, and capsular repair influence joint mechanics to balance functional mobility.

PURPOSE

To examine the contributions of the capsule and cam deformity to hip joint mechanics. Using in vitro, cadaveric methods, we examined the individual effects of the surgical capsulotomy, cam resection, and capsular repair on passive range of motion and resistance of applied torque.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Twelve cadaveric hips with cam deformities were skeletonized to the capsule and mounted onto a robotic testing platform. The robot positioned each intact hip in multiple testing positions: (1) extension, (2) neutral 0°, (3) flexion 30°, (4) flexion 90°, (5) flexion-adduction and internal rotation (FADIR), and (6) flexion-abduction and external rotation. Then the robot performed applicable internal and external rotations, recording the neutral path of motion until a 5-N·m of torque was reached in each rotational direction. Each hip then underwent a series of surgical stages (T-capsulotomy, cam resection, capsular repair) and was retested to reach 5 N·m of internal and external torque again after each stage. During the capsulotomy and cam resection stages, the initial intact hip's recorded path of motion was replayed to measure changes in resisted torque.

RESULTS

Regarding changes in motion, external rotation increased substantially after capsulotomies, but internal rotation only further increased at flexion 90° (change +32%, P = .001, d = 0.58) and FADIR (change +33%, P < .001, d = 0.51) after cam resections. Capsular repair provided marginal restraint for internal rotation but restrained the external rotation compared with the capsulotomy stage. Regarding changes in torque, both internal and external torque resistance decreased after capsulotomy. Compared with the capsulotomy stage, cam resection further reduced internal torque resistance during flexion 90° (change -45%, P < .001, d = 0.98) and FADIR (change -37%, P = .003, d = 1.0), where the cam deformity accounted for 21% of the intact hip's torsional resistance in flexion 90° and 27% in FADIR.

CONCLUSION

Although the capsule played a predominant role in joint constraint, the cam deformity provided 21% to 27% of the intact hip's resistance to torsional load in flexion and internal rotation. Resecting the cam deformity would remove this loading on the chondrolabral junction.

CLINICAL RELEVANCE

These findings are the first to quantify the contribution of the cam deformity to resisting hip joint torsional loads and thus quantify the reduced loading on the chondrolabral complex that can be achieved after cam resection.

Mini Breaks, Many Benefits: Development and Pilot Testing of an Intraoperative Microbreak Stretch Web-Application for Surgeons

Periodic intraoperative microbreaks with calesthenic exercises performed within the sterile field improved self-reported mental focus (38%) and physical performance (57%) for 56 surgeons. Therefore, targeted stretching exercises and a web-application (web-app) leading the stretches with a reminder system were developed and piloted using user-centered design principles. A focus group with 10 users was conducted to refine the developed app. Seven surgeons (4 females) at a quaternary medical institute piloted the periodic stretching web-app in their operating rooms. At the end of each surgical day, the surgeons completed a short survey about the intraoperative stretching exercises web-app impact on their physical performance, mental focus and workflow disruption. Non-Routine Events were captured during the procedures. Twelve surgical days were followed with a median of 6 microbreaks/day/surgeon. Results showed that better physical performance and lower fatigue were reported (91.7%) across the surgical days, also better mental focus was reported (83.3%) across the surgical days, and less pain/discomfort was reported (100%) across the surgical days, with others reporting no change. The web-app leading sterile field microbreak stretches helped reduce physical pain, discomfort/pain, fatigue, and improve mental focus with minimal disruption for a small sample. The web-app is a promising tool for improving surgeon mental focus and physical performance and potentially musculoskeletal health.

Diagnostic Accuracy of Magnetic Resonance Arthrography in Detecting Intra-articular Pathology Associated with Femoroacetabular Impingement

Purpose  The aim of this study was to assess the diagnostic accuracy of magnetic resonance arthrography (MRA) in the detection of intra-articular lesions of the hip in patients affected by femoroacetabular impingement (FAI) by using arthroscopy as reference standard.

Methods  Twenty-nine consecutive hip arthroscopies performed in 24 patients were considered for the study. Patients had a mean age of 38.3 years. Ultrasound-guided 1.5-T MRA was performed with precontrast short tau inversion recovery, T1-weighted and PD coronal, T1-weighted, and T2-weighted axial with 3-mm-thick slice sequences, and postcontrast T1-weighted fat saturation MRA (Fat-SAT) axial, coronal and oblique sagittal, and T1-weighted Vibe 3D coronal sequences with MPR sagittal, axial, and radial reconstructions with 2-mm-thick slice and coronal density protonil (DP) Fat-SAT. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of MRA were evaluated by comparison arthroscopy for the following intra-articular findings: acetabular and femoral chondral lesions, labral degeneration, labral tears, synovitis, ligamentum teres (LT) tears, CAM lesions, pincer lesions, loose bodies, and osteophytes.

Results  An absolute per cent agreement (100%) was observed for all the variables in the assessment of CAM lesions. Sensitivity, specificity, PPV, and NPV of MRA were 100, 68.4, 72.7, and 100%, respectively, for acetabular chondral lesions; 100, 50, 47.3, and 100%, respectively, for femoral chondral lesions; 33, 85, 20, and 91.6%, respectively, for labral tears; 95, 71, 91.3, and 83.3%, respectively, for labral degeneration; 100, 88, 57.1, and 100%, respectively, for LT tears; 33.3, 85, 50, and 73.9%, respectively, for pincer lesions; 50, 96, 66.6, and 92.3%, respectively, for intra-articular loose bodies; and 100, 73.9, 50, and 100%, respectively, for osteophytes.

Conclusion  MRA may play an important role in detecting intra-articular lesions associated with FAI. This might be helpful for the preoperative planning before hip arthroscopy.

Level of Evidence  This is a Level 2, diagnostic accuracy study compared with gold standard.

Clinical Outcomes According to Femoral and Acetabular Version After Periacetabular Osteotomy

Background:

Patients with acetabular dysplasia often have abnormal femoral and acetabular version. The effect of combined femoral and acetabular version on clinical outcomes after periacetabular osteotomy for the treatment of acetabular dysplasia remains unclear. The purposes of the present study were (1) to evaluate the association of combined femoral and acetabular version with clinical outcome after periacetabular osteotomy and (2) to investigate the association of femoral version independently with clinical outcome after periacetabular osteotomy.

Methods:

We retrospectively reviewed the records for 92 consecutive patients (95 hips) who had undergone periacetabular osteotomy for the treatment of symptomatic acetabular dysplasia. The patient cohort comprised 85 females and 7 males with a mean age of 38.9 years at the time of surgery. The mean duration of follow-up was 4.8 years (range, 2.0 to 7.2 years). Femoral and acetabular version and the alpha angle were measured on postoperative computed tomography scans. Clinical outcomes included range of motion and the modified Harris hip score. Analysis of variance was used to investigate the effect of femoral version on clinical outcomes. Analysis of covariance was used to adjust for potential covariates.

Results:

Combined femoral and acetabular version after periacetabular osteotomy was slightly, but significantly, correlated with postoperative flexion (r = 0.222; p = 0.031) and internal rotation in flexion (r = 0.326; p = 0.001). Patients with mild femoral version (<15°) experienced significantly less postoperative internal rotation in flexion than those with severe femoral version (>35°); however, this difference was lost after adjustment for potential covariates. There were no differences among femoral version groups (mild, moderate, and severe) in terms of improvements in the clinical outcomes of pain, function, and activity.

Conclusions:

Combined femoral and acetabular version after periacetabular osteotomy was significantly correlated with postoperative range of motion. Abnormality of femoral version associated with acetabular dysplasia did not demonstrate any effect on the clinical outcomes of periacetabular osteotomy.

Level of Evidence:

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Advanced Concepts in Hip Morphology, Associated Pathologies, and Specific Rehabilitation for Athletic Hip Injuries

Hip and groin injuries comprise up to 17% of athletic injuries and can pose rehabilitation challenges for many athletes. Injuries involving abnormal femoral acetabular morphology, reduced range of motion, and decreased lumbopelvic strength and endurance also may increase the risk of injury to lower extremities and delay return to play if proper rehabilitation does not take place. The rehabilitation of athletic hip injuries requires a multifaceted interdisciplinary approach that manages the interplay of multiple factors to restore preinjury function and facilitate return to play. Emphasis should be placed on activity modification, preservation of the arcs of range of motion, functional strengthening of the lumbopelvic core, and optimization of proprioceptive and neuromechanical strategies. Communication between providers and the injured athlete also is crucial to ensure that proper therapeutic approaches are being applied.

Position of the greater trochanter and functional femoral antetorsion: Which factors matter in the management of femoral antetorsion disorders?

Aims

The primary aim of this study was to define and quantify three new measurements to indicate the position of the greater trochanter. Secondary aims were to define 'functional antetorsion' as it relates to abductor function in populations both with and without torsional abnormality.

Patients and Methods

Three new measurements, functional antetorsion, posterior tilt, and posterior translation of the greater trochanter, were assessed from 61 CT scans of cadaveric femurs, and their reliability determined. These measurements and their relationships were also evaluated in three groups of patients: a control group (n = 22), a 'high-antetorsion' group (n = 22) and a 'low-antetorsion' group (n = 10).

Results

In the cadaver group, the mean anatomical antetorsion was 14.7° (sd 8.5; 0 to 36.5) and the functional antetorsion 21.5° (sd 8.1; 3.6 to 44.3): the posterior tilt was 73.3° (sd 10.8; 46.9 to 88.7) and the posterior translation 0.59 (sd 0.2; 0.2 to 0.9). These measurements had excellent intra and interobserver agreement with a range from 0.93 to 0.99. When the anatomical antetorsion decreased, the greater trochanter was more tilted and translated posteriorly in relation to the axis of the femoral neck, and the difference between functional and anatomical antetorsion increased. The results the three patient groups were similar to those of the cadaver group.

Conclusion

The position of the greater trochanter and functional antetorsion varied with anatomical antetorsion. In the surgical management of femoral retrotorsion, subtrochanteric osteotomy can result in an excessively posterior position of the greater trochanter and an increase in functional antetorsion. Cite this article: Bone Joint J 2018;100-B:712-19.

Anatomic Predictors of Sagittal Hip and Pelvic Motions in Patients With a Cam Deformity

BACKGROUND

As there is a high prevalence of patients with cam deformities and no ongoing hip dysfunction, understanding the biomechanical factors predicting the onset of symptoms and degenerative changes is critical. One such variable is how the spinopelvic parameters may influence hip and pelvic sagittal mobility. Hypothesis/Purpose: Pelvic incidence may predict sagittal hip and pelvic motions during walking and squatting. The purpose was to determine which anatomic characteristics were associated with symptoms and how they influenced functional hip and pelvic ranges of motion (ROMs) during walking and squatting.

STUDY DESIGN

Controlled laboratory study.

METHODS

Fifty-seven participants underwent computed tomography and were designated either symptomatic (n = 19, cam deformity with pain), asymptomatic (n = 19, cam deformity with no pain), or control (n = 19, no cam deformity or pain). Multiple femoral (cam deformity, neck angle, torsion), acetabular (version, coverage), and spinopelvic (pelvic tilt, sacral slope, pelvic incidence) parameters were measured from each participant's imaging data, and sagittal hip and pelvic ROMs during walking and squatting were recorded using a motion capture system.

RESULTS

Symptomatic participants had large cam deformities, smaller femoral neck-shaft angles, and larger pelvic incidence angles compared with the asymptomatic and control participants. Discriminant function analyses confirmed that radial 1:30 alpha angle (λ₁ = 0.386), femoral neck-shaft angle (λ₂ = 0.262), and pelvic incidence (λ₃ = 0.213) ( P < .001) were the best anatomic parameters to classify participants with their groups. Entering these 3 parameters into a hierarchical linear regression, significant regressions were achieved for hip ROM only when pelvic incidence was included for walking ( R² = 0.20, P = .01) and squatting ( R² = 0.14, P = .04). A higher pelvic incidence decreased walking hip ROM ( r = -0.402, P = .004). Although symptomatic participants indicated a trend of reduced squatting hip and pelvic ROMs, there were no significant regressions with the anatomic parameters.

CONCLUSION

A cam deformity alone may not indicate early clinical signs or decreased ROM. Not only was pelvic incidence a significant parameter to classify the participants, but it was also an important parameter to predict functional ROM. Symptomatic patients with a higher pelvic incidence may experience limited sagittal hip mobility.

CLINICAL RELEVANCE

Patients with symptomatic femoroacetabular impingement showed a higher pelvic incidence and, combined with a cam deformity and varus neck, can perhaps alter the musculature of their iliopsoas, contributing to a reduced sagittal ROM. With an early and accurate clinical diagnosis, athletes could benefit from a muscle training strategy to protect their hips.

Impingement-type bony morphology was related to cartilage defects, but not pain in professional ballet dancers' hips

OBJECTIVES

Professional ballet dancers may have hip bony morphology that predisposes them to cartilage or labral injury. However, the relationship between bony morphology and pathology has not been investigated in ballet. This study investigates associations between bony morphology, chondrolabral defects and hip pain in ballet dancers.

DESIGN

Cross-sectional study.

METHODS

33 male and female professional ballet dancers, (mean age 27 years (range 19-39)), completed questionnaires with hip pain measured on a visual analogue scale; and underwent 3.0-T magnetic resonance imaging (3T MRI) to measure lateral centre edge angles (LCEA), alpha angles in the anterior and superior position, femoral neck-shaft angles (NSA) and acetabular version angles; and to detect acetabular labral tear and articular cartilage defects.

RESULTS

Seventeen dancers (51.5%) had impingement-type (alpha angle>50.5° or acetabular version <10° or >20°) and 19 (58%) had instability-type (LCEA<25° or NSA>135°) bony morphology. Cartilage defect prevalence was higher in dancers with impingement-type bony morphology (n=14) compared to those without impingement-type morphology (n=4, p=0.001). There was no relationship between instability-type bony morphology and cartilage defects (p>0.05). There was no relationship between labral tears and bony morphology (p>0.05). Neither chondrolabral pathology nor any morphological feature were associated with hip pain (p>0.05 for all).

CONCLUSIONS

Impingement-type bony morphology was related to cartilage defects, but not labral tear. Hip pain was not associated with pathology or bony morphology. Longitudinal studies are warranted to determine if bony features, such as cam morphology, acetabular retroversion or anteversion, are precursors to symptomatic hip joint injury or osteoarthritis.

Diminished femoral head-neck offset and the restricted hip range of motion suggesting a possible role in ACL injuries

PURPOSE

Femoroacetabular impingement may be associated with anterior cruciate ligament (ACL) injuries. The purpose of this study was to determine the head-neck offset, as measured by 45° Dunn's view alpha angles, in patients with ACL injuries compared to control subjects.

METHODS

In this retrospective study, 140 consecutive non-professional athletes with primary ACL ruptures confirmed with knee arthroscopy and 100 consecutive patients with non-ACL injury were enrolled. Hip range of motion was assessed in lower extremities in all participants, and alpha angle was calculated according to 45° Dunn's view radiographs.

RESULTS

There is not any difference in age, gender distribution, height, weight, and BMI between groups. Internal rotation, abduction, and adduction of the hip were significantly decreased in ACL-injured patients comparing with control subjects (p < 0.001). ACL-injured patients had also a significantly higher alpha angle comparing to the control individuals (p < 0.001). The mean of alpha angle in the ACL-injured patients was 56.1 (SD 10.1) and in the non-ACL-injured group was 49.3 (SD 9.4).

CONCLUSIONS

The patients in ACL-injured group showed a significant restriction in hip range of motion and also a diminished femoral head-neck offset suggesting a possible role of these findings in the outcome assessed.

LEVEL OF EVIDENCE

III.

Surgeon symptoms, strain, and selections: Systematic review and meta-analysis of surgical ergonomics

Background

Many surgeons experience work-related pain and musculoskeletal symptoms; however, comprehensive reporting of surgeon ailments is lacking in the literature. We sought to evaluate surgeons' work-related symptoms, possible causes of these symptoms, and to report outcomes associated with those symptoms.

Materials and methods

Five major medical indices were queried for articles published between 1980 and 2014. Included articles evaluated musculoskeletal symptoms and ergonomic outcomes in surgeons. A meta-analysis using a fixed-effect model was used to report pooled results.

Results

Forty articles with 5152 surveyed surgeons were included. Sixty-eight percent of surgeons surveyed reported generalized pain. Site-specific pain included pain in the back (50%), neck (48%), and arm or shoulder (43%). Fatigue was reported by 71% of surgeons, numbness by 37%, and stiffness by 45%. Compared with surgeons performing open surgery, surgeons performing minimally invasive surgery (MIS) were significantly more likely to experience pain in the neck (OR 2.77 [95% CI 1.30–5.93]), arm or shoulder (OR 4.59 [2.19–9.61]), hands (OR 2.99 [1.33–6.71], and legs (OR 12.34 [5.43–28.06]) and experience higher odds of fatigue (8.09 [5.60–11.70]) and numbness (6.82 [1.75–26.65]). Operating exacerbated pain in 61% of surgeons, but only 29% sought treatment for their symptoms. We found no direct association between muscles strained and symptoms.

Conclusions

Most surgeons report work-related symptoms but are unlikely to seek medical attention. MIS surgeons are significantly more likely to experience musculoskeletal symptoms than surgeons performing open surgery. Symptoms experienced do not necessarily correlate with strain.

•

68% of surveyed surgeons reported experiencing generalized pain from operating.

•

Minimally-invasive surgeons were more likely to report pain, fatigue, and numbness.

•

Only 29% of surgeons reported seeking treatment for symptoms.

•

No association between objective strain on muscles and reported symptoms was found.

Prevalence of asymptomatic femoroacetabular impingement in Turkey; cross sectional study

OBJECTIVES

Femoroacetabular impingement (FAI) is one of the causes of hip pain in young-adult patients. The purpose of our study is to determine the prevalence of radiological FAI findings in asymptomatic population in Turkey.

METHODS

Trauma patients aged 18-65 years who applied to the emergency service between September 2015 and September 2016 were retrospectively evaluated for this study. After a preliminary study and power analysis, 2152 hips of the 1076 previously asymptomatic patients were evaluated radiologically with pelvis antero-posterior and frog-leg radiographs. On radiographs of these patients; alpha angle, lateral central edge angle (LCEA), Tönnis angle (TA) and collodiaphyseal angle were measured. Alpha angle values higher than 55° were noted as cam type FAI. TA values lower than 0° or LCEA values higher than 39° were noted as pincer type FAI. LCEA values lower than 25° or TA values higher than 10° were noted as acetabular dysplasia.

RESULTS

Mean age of 1076 patients (602 female, 474 male) was 42.1 ± 15.6 years. The assessment showed that 15.9% of the patients had cam type, 10.6% had pincer type, 3.1% had combined type FAI and 9.3% had findings of acetabular dysplasia. The prevalence of asymptomatic FAI is significantly more in males (46%) in comparison to females (17%) in Turkey.

CONCLUSION

Even though FAI is considered to be a pathology associated with hip osteoarthritis; it is very common in asymptomatic population. In this respect, our study showed that prevalence of radiological FAI findings in asymptomatic adult population was 29.6% in Turkey.

Abnormal femoral antetorsion-a subtrochanteric deformity

Femoral rotational malalignment is associated with pain and functional disability and may be a contributing factor to hip impingement as well as to instability. In general, the deformity can be addressed surgically by rotational osteotomy. However, the anatomic location of the deformity is debated. The goal of the present study was to narrow down the anatomic site of deformity using the lesser trochanter (LT) as an additional landmark. One hundred and eight patients underwent computer tomography (CT)-based rotational analysis of their lower extremities. Femoral torsion (FT) and LT torsion (LTT) were measured. The combined angle (CoA) between FT and LTT was calculated. Statistical evaluation was done by multiple regression analysis. Ninety-seven extremities were examined for FT and LTT. Average age was 41 years (SD = 16.9) with a range of 18–85 years. Mean values were 20° for FT (SD = 12.2) and −16° for LTT (SD = 11.3). Mean CoA was 37.2 (SD = 8.7). Statistical analysis reveals a strong linear relationship between FT and LTT (y=31+0.74x) and a weaker relationship between FT and CoA (y=31+0.24x). This study identifies the LT as a reliable landmark and shows a strong linear relationship between the orientation of the LT and the overall torsion of the femur below and above the LT with about two-thirds of torsional changes occurring distal to it. These results provide a considerable indication for a subtrochanteric osteotomy to address correction of femoral rotational deformity at its anatomical origin.

Level of Evidence: Level III, observational study.

Assessment of the alpha angle and mobility of the hip in patients with noncontact anterior cruciate ligament injury

PURPOSE

To evaluate the alpha angle of the hip in patients with noncontact anterior cruciate ligament (ACL) injury and compare it with patients without injury. In addition, external and internal rotation of the hip was assessed and correlated with the alpha angle.

METHODS

The alpha angle of the ipsilateral hip was assessed in 41 subjects with non-contact ACL tear and compared with 39 subjects with no tear. The external and internal rotation of the ipsilateral hip was also evaluated.

RESULTS

The alpha angle was larger in subjects with noncontact ACL injury. The mean was 70.31° (±13.92°) compared with 58.55° (±13.95°) in the control group (p < 0.001). The groups were similar when considering the external, internal, and sum of rotation of the ipsilateral hip. There was no correlation between the alpha angle and decreased rotational range of motion of the hip in either group (p > 0.05).

CONCLUSION

Patients with noncontact ACL injury presented a greater alpha angle when compared with the group without tear. There was no difference in the rotational mobility of the hip between groups, nor was there a correlation between the increase in the alpha angle and the decrease in the rotational mobility of the hip.

Isolated Acetabuloplasty and Labral Repair for Combined-Type Femoroacetabular Impingement: Are We Doing Too Much?

PURPOSE

To evaluate patient outcomes after isolated arthroscopic volumetric acetabular osteoplasty and labral repair for the treatment of patients with combined femoroacetabular impingement (FAI) lesions.

METHODS

A review of a prospectively collected registry identified 86 patients (106 hips) with an average age of 38.1 years (range, 17-59 years) with combined-type FAI that underwent isolated acetabular osteoplasty and labral repair. Preoperative α-angle, degree of radiographic degenerative changes, and presence of a crossover sign were recorded. Clinical outcomes were assessed with the modified Harris Hip Score (mHHS), International Hip Outcome Tool-12 (iHOT-12), Hip Outcome Score Sport-Specific Subscale (HOS-SSS), and patient satisfaction score (out of 10) at a minimum 2-year follow-up.

RESULTS

Clinical follow-up was obtained at a mean follow-up of 37.2 months (range, 27.9-79.2 months). Patients with Tönnis grade 0 and I findings had significantly higher mHHS (83.5 vs 71.5, P = .01), HOS-SSS (81.3 vs 59.9, P = .02), and iHOT-12 scores (71.1 vs 58.8, P = .04) compared to patients with Tonnis grade II changes. However, patient satisfaction scores (8.0 vs 7.2, P = .45) were no different. No significant difference was noted between unilateral and bilateral hip patient outcome scores. Patient age and preoperative α-angles did not correlate with any outcome scores (all R² <0.05). There were no cases of revision surgery or progression to arthroplasty.

CONCLUSIONS

Isolated acetabular decompression may adequately address the underlying impingement in combined-type FAI while avoiding the risks associated with femoral-sided decompression. Good to excellent patient-reported outcomes and satisfaction scores were noted with significantly higher scores in patients with minimal arthritic change. Patient age and preoperative α-angle had less effect on postoperative outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Restricted Hip Rotation Is Correlated With an Increased Risk for Anterior Cruciate Ligament Injury

PURPOSE

The primary purpose was to compare ipsilateral hip internal rotation (IR) in male and female athletes with or without an anterior cruciate ligament (ACL) tear. A secondary purpose was to compare radiographic markers of femoroacetabular impingement (FAI) in patients with or without an ACL tear.

METHODS

In this prospective case-control study, based on a power analysis, a convenience sample of 25 ACL-injured and 25 control patients matched by age and gender were examined over 14 months. The ACL injury group included preoperative patients 12-40 years old with an ACL rupture within the previous 3 months with no prior lower extremity injuries, ligamentous laxity, or arthralgias. Controls included patients presenting with an upper extremity complaint with no history of knee injury. In the outpatient clinic, hip axial rotation range of motion was measured with a goniometer on physical examination and hip radiographs were evaluated for morphologic variations consistent with FAI. Univariate analysis of variance was used to examine differences between groups.

RESULTS

Each group had 13 males and 12 females, average ages of 22.8 ± 7.2 years (ACL group) versus 24.5 ± 7.9 years (controls; P = .439). The average sum of hip rotation (internal plus external) in patients with an ACL tear was 60.3 ± 12.4° compared with 72.6 ± 17.2° in controls (P = .006). ACL-injured patients had decreased hip IR compared with controls, with respective mean measurements of 23.4 ± 7.6° versus 30.4 ± 10.4° (P = .009). For every 10° increase in hip IR, the odds of having an ACL tear decreased by a factor of 0.419 (P = .015).

CONCLUSIONS

Risk of ACL injury is associated with restricted hip IR, and as hip IR increases, the odds of having an ACL tear decreases. In addition, ACL injury is associated with FAI in a generalized population of male and female athletes, although causality cannot be determined and most ACL-injured patients do not exhibit hip complaints.

LEVEL OF EVIDENCE

Level II, prognostic, prospective cohort study.

Femoral Component Revision of Total Hip Arthroplasty

Modern primary total hip arthroplasty (THA) is among the most successful operations in medicine. It has been a consistently effective treatment for end-stage osteoarthritis of the hip. With the increasing number of primary THA procedures being performed and the decreasing age of patients undergoing the procedure, there is an inevitable associated increase in revision burden for arthroplasty surgeons. Revision THA is most often indicated for instability, aseptic loosening, osteolysis, infection, periprosthetic fracture, component malposition, and catastrophic implant failure. Understanding the etiology of THA failure is essential for guiding clinical decision making. Femoral component revision presents a complex challenge to the arthroplasty surgeon because of modern implant design as well as bone loss in the proximal femur. Thorough patient evaluation, defect classification, and well-executed surgical reconstruction based on comprehensive preoperative planning may determine the postoperative results. Knowledge of various reconstructive options and the indications for each is necessary to achieve a successful outcome. This article highlights the most common indications for revision after THA and offers recommendations for how to approach revision of the femoral component. Specifically, the authors review preoperative assessment, common classification systems for femoral deficiency, techniques for component extraction, and modalities of femoral component fixation. [Orthopedics. 2016; 39(6):e1129-e1139.].

Effect of angular deformities of the proximal femur on impingement-free hip range of motion in a three-dimensional rigid body model

INTRODUCTION

Abnormalities in hip morphology can reduce range of motion (ROM) through femoroacetabular impingement (FAI). Structural issues, such as asphericity of the head-neck junction and regional or global acetabular over-coverage, have been extensively discussed in the literature. The effect of varying femoral neck-shaft angle or torsion on native hip range of motion, however, has been poorly studied. Our hypothesis was that varying neck-shaft angles or femoral torsion affect the impingement-free ROM of the hip and can be treated by femoral osteochondroplasty or acetabular rim resection.

MATERIAL AND METHODS

A computer-aided design tool and a 3-D model of the hip were used to simulate incremental deformation of the proximal femur. Neck-shaft angles ranging from 90-160°, and femoral torsions ranging from -15-50°, were created. Femoroacetabular impingement was defined as bone-to-bone contact within physiological hip ROM, as described in the literature.

RESULTS AND CONCLUSION

With decreasing neck-shaft angles (≤110°) or femoral torsion (≤10°), impingement occurred at the anterosuperior rim area. With increasing neck-shaft angles (≥135°) and femoral torsion (≥25°) posteroinferior or ischiofemoral impingement occurred. Acetabular rim trimming could compensate for neck-shaft angles ≥90° and femoral torsion ≥-5°, without creating acetabular dysplasia. Femoral impingement zones in low neck-shaft and low femoral torsion angles were found to be distal to the head-neck junction at the mid-cervical region. The cross-sectional area at this neck region was the smallest, and thus osteochondroplasty at this location may prove potentially dangerous.

Cytokines as a predictor of clinical response following hip arthroscopy: minimum 2-year follow-up

Hip arthroscopy in patients with osteoarthritis has been shown to have suboptimal outcomes. Elevated cytokine concentrations in hip synovial fluid have previously been shown to be associated with cartilage pathology. The purpose of this study was to determine whether a relationship exists between hip synovial fluid cytokine concentration and clinical outcomes at a minimum of 2 years following hip arthroscopy. Seventeen patients without radiographic evidence of osteoarthritis had synovial fluid aspirated at time of portal establishment during hip arthroscopy. Analytes included fibronectin–aggrecan complex as well as a multiplex cytokine array. Patients completed the modified Harris Hip Score, Western Ontario and McMaster Universities Arthritis Index and the International Hip Outcomes Tool pre-operatively and at a minimum of 2 years following surgery. Pre and post-operative scores were compared with a paired t-test, and the association between cytokine values and clinical outcome scores was performed with Pearson’s correlation coefficient with an alpha value of 0.05 set as significant. Sixteen of seventeen patients completed 2-year follow-up questionnaires (94%). There was a significant increase in pre-operative to post-operative score for each clinical outcome measure. No statistically significant correlation was seen between any of the intra-operative cytokine values and either the 2-year follow-up scores or the change from pre-operative to final follow-up outcome values. No statistically significant associations were seen between hip synovial fluid cytokine concentrations and 2-year follow-up clinical outcome assessment scores for those undergoing hip arthroscopy.

The Hip in Ice Hockey: A Current Concepts Review

Ice hockey is a fast, physical sport with unique associated biomechanical demands often placing the hip in forced and repetitive supraphysiological ranges of motion. Ice hockey players commonly endure and are sidelined by nebulous groin injury or hip pain. Underlying causes can be chronic or acute and extra-articular, intra-articular, or "hip-mimicking." This article serves to review common hip-related injuries in ice hockey. For each, we define the particular condition; comment on risk factors and preventive strategies; discuss key historical, physical examination, and imaging findings; and finally, suggest nonoperative and/or operative treatment plans.

Arthroscopic Management of Femoroacetabular Impingement in Adolescents

PURPOSE

To report the outcomes of hip arthroscopy for adolescent patients with symptomatic femoroacetabular impingement (FAI) in relation to a control group of adult patients treated arthroscopically for FAI.

METHODS

All patients undergoing hip arthroscopy were assessed with a modified Harris Hip Score preoperatively and postoperatively at 3, 12, 24, and 60 months. Inclusion criteria were all patients less than 18 years of age who underwent arthroscopic surgery for symptomatic FAI and had achieved minimum 1-year follow-up. These cases were gathered over an 8-year period.

RESULTS

The study group consisted of 122 consecutive hips (108 patients), and the control group consisted of 122 hips. Follow-up averaged 30 months (range 12 to 60 months). For the study group, the average age was 16 years, with 55 males and 65 females; control group average age was 36 years, with 71 males and 51 females. In the study group, the average scores were preoperative 68.3 and postoperative 93.6, with a 25.4-point improvement. The duration of symptoms averaged 16.6 months, and 95.9% participated in athletic activities. The study group included 36 cam, 17 pincer, and 69 combined lesions. One hundred eleven labral tears underwent 85 refixations and 26 debridements; there were 101 acetabular chondral lesions (51 grade 3 or 4), with 4 microfractures and 3 femoral chondral lesions. Among the control group, the average scores were preoperative 63.3 and postoperative 85.5, with a 22.2-point improvement. The duration of symptoms averaged 31.2 months, and 61.5% participate in athletic activities. The control group consisted of 53 cam, 5 pincer, and 64 combined FAI lesions. One hundred three labral tears underwent 52 refixations and 51 debridements; there were 112 acetabular lesions (92 grade 3 or 4), with 20 microfractures and 17 femoral chondral lesions. The study group included 15 concomitant extra-articular procedures, and there were 5 in the control group. In the study group, 4 underwent repeat arthroscopy and 1 periacetabular osteotomy; in the control group, 1 patient underwent repeat arthroscopy.

CONCLUSIONS

Favorable outcomes of arthroscopic management of FAI in adolescents are reported compared with an adult control group. The present data support that arthroscopy does have a role in the management of FAI in adolescents.

LEVEL OF EVIDENCE

Level III, case control study.

Avoiding Failure in Hip Arthroscopy: Complications, Pearls, and Pitfalls

Although most patients have successful outcomes after hip arthroscopy, a minority of patients experience complications that may impact their recovery and long-term benefit. As most of these complications can be minimized by appropriate surgical technique, many tips have been recommended. Additionally, the reasons behind clinical failure postoperatively have been scrutinized, which include, most commonly, incomplete correction of osseous pathomorphology, underappreciated preexisting hip osteoarthritis, and/or an incorrect preoperative diagnosis. Meticulous preoperative planning, evaluation of advanced imaging studies, and proper patient selection will help to reduce the number of postoperative failures and increase the chance of a successful outcome following hip arthroscopy.

Return to Play Following Hip Arthroscopy

Femoroacetabular impingement may be particularly disabling to the high-demand athlete, especially those with significant cutting and pivoting requirements. If nonoperative treatment fails to adequately alleviate symptoms or sufficiently restore function in the athlete, hip arthroscopy can lead to improved pain, improved range of motion, and high rates of return to play with proper postoperative rehabilitation. The rate of return to previous level of competition is also high with accurate diagnosis and well-executed correction of deformity. A clear understanding of the etiology, diagnosis, management, and outcomes is essential for clinicians to optimally help patients to return to play.