Femoroacetabular impingement: current concepts in diagnosis and treatment

Femoral rotational osteotomy for femoroacetabular impingement: A systematic review

Purpose

To synthesize existing literature regarding the indications and outcomes of femoral rotational osteotomies (FDO) for femoroacetabular impingement (FAI) due to.

Methods

Medline, Cochrane, and Embase were searched using keywords "femoroacetabular impingement", "rotational osteotomy" and others to identify FAI patients undergoing FDO. Double-screened studies were reviewed by blinded authors according to inclusion criteria. Data from full texts was extracted including study type, number of patients, sex, mean age, surgical indication, type of dysplasia, associated pathology, surgical technique, follow-up, and pre-op/post-op evaluations of the following: impingement test, femoral version (FV), 'other angles measured', outcome scores, range of motion (ROM).

Results

7 studies including 91 patients (97 FDO surgeries), 73 females (80 %) with mean age of 28.3 years, and follow-up mean of 2.44 ± 2.83 years. Pain or impingement was the most common clinical indication, while others included aberrant FV and ROM measurements for both anteverted and retroverted femurs. There were reports of FDO being performed with concomitant procedures addressing other pathology. Various outcome scores and ROM measurements showed postoperative improvement after FDO. Complication data was sparse, preventing aggregation. The rate of unplanned reoperation was 40 % (where reported), with 'hardware removal' being the most common.

Conclusions

FDO is effective in treating FAI due to increased FV, improving clinical symptoms, and potentially delaying articular degeneration. Hardware removal surgery remains an inherent risk in undergoing FDO. Further work is needed to discover indications warranting FDO as a primary treatment versus hip arthroscopy.

Level of evidence

This review contains 4 studies with Level IV evidence and 3 studies with Level III evidence.

Deep Learning-Assisted Identification of Femoroacetabular Impingement (FAI) on Routine Pelvic Radiographs

To use a novel deep learning system to localize the hip joints and detect findings of cam-type femoroacetabular impingement (FAI). A retrospective search of hip/pelvis radiographs obtained in patients to evaluate for FAI yielded 3050 total studies. Each hip was classified separately by the original interpreting radiologist in the following manner: 724 hips had severe cam-type FAI morphology, 962 moderate cam-type FAI morphology, 846 mild cam-type FAI morphology, and 518 hips were normal. The anteroposterior (AP) view from each study was anonymized and extracted. After localization of the hip joints by a novel convolutional neural network (CNN) based on the focal loss principle, a second CNN classified the images of the hip as cam positive, or no FAI. Accuracy was 74% for diagnosing normal vs. abnormal cam-type FAI morphology, with aggregate sensitivity and specificity of 0.821 and 0.669, respectively, at the chosen operating point. The aggregate AUC was 0.736. A deep learning system can be applied to detect FAI-related changes on single view pelvic radiographs. Deep learning is useful for quickly identifying and categorizing pathology on imaging, which may aid the interpreting radiologist.

MRI texture analysis of acetabular cancellous bone can discriminate between normal, cam positive, and cam-FAI hips

OBJECTIVES

To compare the MRI texture profile of acetabular subchondral bone in normal, asymptomatic cam positive, and symptomatic cam-FAI hips and determine the accuracy of a machine learning model for discriminating between the three hip classes.

METHODS

A case-control, retrospective study was performed including 68 subjects (19 normal, 26 asymptomatic cam, 23 symptomatic cam-FAI). Acetabular subchondral bone of unilateral hip was contoured on 1.5 T MR images. Nine first-order 3D histogram and 16 s-order texture features were evaluated using specialized texture analysis software. Between-group differences were assessed using Kruskal-Wallis and Mann-Whitney U tests, and differences in proportions compared using chi-square and Fisher's exact tests. Gradient-boosted ensemble methods of decision trees were created and trained to discriminate between the three groups of hips, with percent accuracy calculated.

RESULTS

Sixty-eight subjects (median age 32 (28-40), 60 male) were evaluated. Significant differences among all three groups were identified with first-order (4 features, all p ≤ 0.002) and second-order (11 features, all p ≤ 0.002) texture analyses. First-order texture analysis could differentiate between control and cam positive hip groups (4 features, all p ≤ 0.002). Second-order texture analysis could additionally differentiate between asymptomatic cam and symptomatic cam-FAI groups (10 features, all p ≤ 0.02). Machine learning models demonstrated high classification accuracy of 79% (SD 16) for discriminating among all three groups.

CONCLUSION

Normal, asymptomatic cam positive, and cam-FAI hips can be discriminated based on their MRI texture profile of subchondral bone using descriptive statistics and machine learning algorithms.

CLINICAL RELEVANCE STATEMENT

Texture analysis can be performed on routine MR images of the hip and used to identify early changes in bone architecture, differentiating morphologically abnormal from normal hips, prior to onset of symptoms.

KEY POINTS

• MRI texture analysis is a technique for extracting quantitative data from routine MRI images. • MRI texture analysis demonstrates that there are different bone profiles between normal hips and those with femoroacetabular impingement. • Machine learning models can be used in conjunction with MRI texture analysis to accurately differentiate between normal hips and those with femoroacetabular impingement.

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.

Association of Chondrolabral Lesions with Ultrasound-Guided Detection of Pathological Head-Neck Contour

OBJECTIVE

This study aimed to investigate whether the asphericity of the neck-head junction of the femur confirmed via ultrasound is associated with further pathology due to femoro-acetabular impingement (FAI).

METHODOLOGY

After a clinical examination with positive FAI tests, an ultrasound examination of the hip was performed. In the case of asphericity, a quantitative ultrasound-assisted assessment of the hip was performed, followed by contrast-enhanced arthro-MRI with the question of cartilage or labral damage.

RESULTS AND CONCLUSIONS

We included 51 patients with a mean age of 35.25. According to the examination algorithm, asphericity was present in all patients via ultrasonography. The average anterior alpha angle (AAA) determined in ultrasonography was 43.49°. The average AAA on the arthro-MRI was 44.19°. The mean anterior head neck offset (AHNO) in ultrasound was 5.27 mm, and in arthro-MRI, it was 5.36 mm. Arthro-MRI confirmed a bump in 47 patients and a talization disorder in 4 patients. In 49 patients, a labral lesion was found, with one being a re-rupture. Furthermore, in one patient, labral degeneration was identified. Cartilage damage to the hip joint was found in 25 patients. Two patients had neither labral nor cartilage damage in the arthro-MRI. In our study, sonographically confirmed asphericity of the head-neck junction was found in 49 cases, which was associated with further pathology and, according to the current doctrine, was attributable to the FAI and required surgical intervention. This study shows that the detection of a pathologic head and neck contour via ultrasound in combination with positive clinical signs, as present in FAI, is associated with chondrolabral lesions detected via arthro-MRI in 96.1% of cases.

Femoroacetabular Impingement in Ice Hockey Athletes

ABSTRACT

Femoroacetabular impingement (FAI) in ice hockey is a concern for many athletes. The biomechanics of skating and the injury mechanism, prevalence, identification, and treatment protocols currently available for FAI in ice hockey athletes are important for all coaches and practitioners to understand. This article discusses the underlying anatomical issues and biomechanical considerations surrounding FAI. Furthermore, this article describes the interventions that can be used when encountering FAI and well-established protocols to aid in the return to play. Finally, prevention strategies that can aid in injury prevention are discussed.

Telemedicine Evaluation of Hip Ailments

Background During the coronavirus disease 2019 (COVID-19) pandemic, telemedicine has provided new means of patient care while still allowing for physical examination and history to be obtained. Hip ailments are a common musculoskeletal problem leading to limited function. Today, we lack a standardized telemedicine hip evaluation protocol. Aim The aim of this manuscript is to provide an efficient means of extracting relevant information while performing telemedicine examinations of the hip. Methods The authors have created a step-by-step evaluation guide for physicians to evaluate hip complaints, including inspection, palpation, range of motion, strength testing, functional assessment, gait analysis, and special testing, with images of each maneuver. Results  We have developed a table of evaluation questions and instructions and a glossary of images of each maneuver to facilitate hip examination via telemedicine. Conclusions This manuscript provides a structured template for performing a telehealth examination of hip ailments.

Editorial Commentary: Hip Arthroscopy for Femoroacetabular Impingement Syndrome in Adolescents Improves Outcomes: Don't Forget the Young Guns

It has been said that youth is wasted on the young. This notion does not apply to the value that hip arthroscopy provides in managing hip pathology in adolescents. Multiple studies have shown the efficacy of hip arthroscopy as a treatment modality in the adult population for a multitude of hip pathologies, particularly femoroacetabular impingement syndrome. The implementation of hip arthroscopy in the management of femoroacetabular impingement syndrome in the adolescent population is on the rise. More studies illustrating favorable outcomes following hip arthroscopy in adolescents will serve to reinforce its utility as a treatment option for this population. Early intervention and preservation of hip function are of critical importance in a youthful and active patient population. As a word of caution, acetabular retroversion predisposes these patients to an increased risk of revision surgery.

Relationship between the Depth of Acetabuloplasty and Outcomes of Hip Arthroscopy in Patients with Global Pincer Femoroacetabular Impingement: Study with a Minimum Follow-Up Period of 2 Years

OBJECTIVE

There has been no definite consensus on the ideal depth of acetabuloplasty, especially in cases of global pincer femoroacetabular impingement (FAI). This study aims to determine whether the depth of acetabuloplasty influences postoperative outcomes in cases of global pincer FAI.

METHODS

Data were retrospectively collected from patients with global pincer FAI who underwent hip arthroscopy with a minimum follow-up period of 2 years from May 2014 to December 2018. Patients with global pincer FAI were subdivided into low or high resection depth groups based on whether the intraoperative acetabular rim was resected by more than 3 mm. Radiographic measurements; arthroscopic procedures; preoperative and postoperative PROs were recorded. Achievement of MCID and PASS was compared for the VAS, mHHS, HOS-ADL, and iHOT-12. A paired Student t-test was used to evaluate the significance of preoperative and postoperative PROs and two-tailed unpaired Student t-test was used to compare demographic data and PROs between different groups. MCID and PASS were evaluated using the chi-square test or the Fisher's exact test.

RESULTS

A total of 41 hips with global pincer FAI (15 and 26 patients in low or high resection depth groups, respectively) were included in this study. Both groups showed significant postoperative improvements in the scores of all PROs (p < 0.001). Compared to the low resection depth group, the high resection depth group had a lower degree of improvement through hip arthroscopy, which manifested as lower postoperative mHHS scores (94.29 vs. 85.08, p = 0.006), higher VAS scores (0.93 vs. 2.54, p = 0.002), and lower improvements in VAS (-5.00 vs. -3.35, p = 0.028), HOS-ADL (34.99 vs. 23.90, p = 0.017) and iHOT-12 (39.89 vs. 29.27, p = 0.036). Patients in high resection depth group were less likely to achieve the MCID for the VAS score compared to low resection depth group in significant (73.3 vs. 26.9%, p = 0.004).

CONCLUSIONS

For patients with global pincer, the outcomes in high resection depth group were slightly worse than the the low resection depth group. It is indicated that excessive resection of the acetabular rim during the procedure should be avoided.

Telehealth examination of the lumbar spine

BACKGROUND

Telehealth evaluations of musculoskeletal conditions have increased due to the stay-at-home policies enacted during the COVID-19 pandemic. Back pain is one of the most common complaints in primary care. While telehealth may never supplant in-person evaluation of back pain, it is imperative in a changing world to learn to perform this evaluation via telephone or video. Virtual visits rely on history-taking and patient self-reported descriptions of pain elicited from self-palpation or specific movements while on the telephone with the clinician. Video examinations provide a unique way of evaluating the lower back compared to telephone because of the ability to visualize the actions of the patient.

OBJECTIVE

To create an evaluation pathway for examination of the lumbar spine via telehealth.

METHODS

Our group has created a step-by-step evaluation pathway to help physicians direct their patients through typical lumbar examination elements, including inspection, palpation, range of motion, and strength, special, and functional testing.

RESULTS

We have developed a table of questions and instructions and a glossary of images of each maneuver to facilitate lumbar spine examination via telemedicine.

CONCLUSIONS

This paper provides a guide for extracting clinically relevant information while performing telemedicine examinations of the lumbar spine.

Efficacy and safety of preoperative versus postoperative NSAIDs on pain relief in patients undergoing hip arthroscopy surgery: A multicentre, randomized, controlled trial

WHAT IS KNOWN AND OBJECTIVE

Postoperative pain relief is a critical issue for hip arthroscopy surgery (HAS). This study aimed to investigate the effect of preemptive non-steroidal anti-inflammatory drugs (NSAIDs) for postoperative analgesia in femoroacetabular impingement (FAI) patients receiving HAS.

METHODS

This multicenter, randomized, controlled study enrolled 204 FAI patients receiving HAS, then assigned them to preoperative (PRE, N = 103) or postoperative (POS, N = 101) group as a 1:1 ratio; the PRE group administrated NSAIDs from 24 h pre-surgery to day 7 (D7) post-surgery, while the POS group administrated NSAIDs from 12 h post-surgery to D7 post-surgery.

RESULTS AND DISCUSSION

Pain at rest was reduced at D1 (p = 0.016) and D2 (p = 0.023); pain at movement was decreased at D1 (p = 0.002), D2 (p = 0.020), and D3 (p = 0.030) in the PRE group compared with POS group, but not at other time points (all p > 0.05). Patient's satisfaction was increased at D1 (p = 0.013) and D3 (p = 0.029) in the PRE group compared to the POS group, but not at D7 (p = 0.145). Pethidine was less consumed at D3 (p = 0.038) and D7 (p = 0.017) in the PRE group in contrast with the POS group. Harris hip scores were similar at D7 (p = 0.124), month 1 (M1) (p = 0.273), and M3 (p = 0.360) between groups. Adverse events incidence was similar between groups (all p > 0.05). Besides, subgroup analysis discovered that pain was not influenced by the types of NSAID in both groups (all p > 0.05).

WHAT IS NEW AND CONCLUSION

Starting NSAIDs before HAS provides better short-term pain relief and improves patient's satisfaction compared with its postoperative utilization, while does not induce additional adverse events in FAI patients.

Patterns of labral tears and cartilage injury are different in femoroacetabular impingement and dysplasia

The aim of this study was to assess injury patterns and risk factors of the acetabular labrum and associated cartilage in patients with femoroacetabular impingement (FAI) versus dysplasia. We retrospectively reviewed 137 patients diagnosed with labral tears and FAI or dysplasia (74 or 63 cases, respectively) through an arthroscopic procedure. Labral and concomitant cartilage injuries were evaluated. Demographics and radiological variables [lateral center-edge angle (LCEA), anterior center-edge angle, acetabular index (AI), acetabular version and alpha angle] were evaluated as risk factors for labral and cartilage injuries. Detachment of acetabular cartilage with intact labro-cartilaginous junction was the most common in dysplasia, whereas cartilage delamination from the labro-cartilaginous junction was more common in FAI (P < 0.001). A higher body mass index was significantly associated with delamination injury in FAI (odds ratio 1.226; 95% CI 1.043–1.441; P = 0.013). A significant correlation was evident between detachment injury and a larger AI in dysplasia (odds ratio 1.127; 95% CI 1.000–1.270; P = 0.049). In addition, symptom duration was positively correlated with the extent of labral tearing in FAI (P = 0.013), whereas the smaller LCEA was correlated with the larger extent of labral tearing in dysplasia (P = 0.044). FAI and dysplasia patients exhibited different labral and cartilage injury patterns. Increased body mass index was correlated with delamination injury in FAI, whereas an increased AI was associated with detachment injury in dysplasia. Greater tearing was associated with a longer symptom duration in FAI, and a decreased LCEA was a risk factor for the extent of tearing in dysplasia.

Level of evidence

Level III. Case–control study.

Two-Tiered Resection of Cam Lesions in Hip Femoroacetabular Impingement: Optimizing Femoral Head Sphericity

Hip arthroscopy is one of the most rapidly growing fields in orthopaedic surgery. One of the most frequent pathologies treated with hip arthroscopy remains femoroacetabular impingement, which is addressed by labral repair and femoral osteoplasty. The most commonly cited reason for failure of arthroscopic treatment of femoroacetabular impingement is under-resection of the cam lesion. Surgeons frequently use evaluations of preoperative images, intraoperative fluoroscopy, and dynamic range of motion to ensure adequate resection. In this article, we describe a reproducible and standardized technique to assist in appropriate resection. This is achieved by a 2-tiered resection technique: Tier 1 aims to set the depth of resection and restore the head-neck offset. Tier 2 then matches the depth of the resection set by tier 1 and allows for retention of appropriate transition of the proximal convexity to the distal concavity seen in more ideally shaped femoral heads. With this technique, we offer a tool to avoid under-resection in the area of maximal conflict while simultaneously minimizing the risk of proximal over-resection and thus compromising the fluid seal dynamics of the joint in deeper flexion angles.

Conservative therapy versus arthroscopic surgery of femoroacetabular impingement syndrome (FAI): a systematic review and meta-analysis

Purpose

FAI (femoroacetabular impingement syndrome) is a common cause of hip pain, resulting in a decreased life quality. This study aims to compare the postoperative clinical outcome between arthroscopic surgery (AT) and conservative treatment (CT).

Method

The six studies were selected from PubMed, Embase and OVID database. The data were extracted and analyzed by RevMan5.3. Mean differences and 95% confidence intervals were calculated. RevMan5.3 was used to assess the risk of bias.

Result

Six observational studies were assessed. The methodological quality of the trials indicated five of six studies had a low risk of bias and one article had a high risk of bias. The differences were statistically significant between AT and CT for HOS (follow-up for 6 months), iHOT-33 (follow-up for 6 months) improvement, iHOT-33 (follow-up for 12 months) improvement, iHOT-33 (follow-up for 12 months), EQ-5D-5L index score (follow-up for 12 months) and AT showed higher benefits than CT. Meanwhile no statistically significant were found in iHOT-33 (follow-up for 6 months), EQ-5D-5L index score (follow-up for 6 months), EQ5D-VAS (follow-up for 6 months) and EQ5D-VAS (follow-up for 12 months).

Conclusion

AT and CT both can have clinical effects when facing FAI. In our meta-analysis, hip arthroscopy is statistically superior to conservative treatment in both long-term and short-term effects.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

LEVEL OF EVIDENCE

Retrospective cohort, level III.

Outcomes and Survivorship at a Median of 8.9 Years Following Hip Arthroscopy in Adolescents with Femoroacetabular Impingement: A Matched Comparative Study with Adults

BACKGROUND

Because of the unique theoretical surgical risks, including osteonecrosis, acute iatrogenic slipped capital femoral epiphysis, and epiphyseal injury, the optimal treatment strategy for femoroacetabular impingement (FAI) in growing adolescents has yet to be established. The aim of this study was to compare the clinical outcomes of primary arthroscopic treatment of FAI in growing adolescents with a matched adult group.

METHODS

Patients with FAI who underwent arthroscopic treatment with a minimum follow-up of 2 years were included. Patients with previous ipsilateral hip surgery, an Outerbridge grade of ≥3, a preoperative Tönnis grade of ≥2, or evidence of dysplasia (lateral center-edge angle of <25°) were excluded. Eligible patients who were ≤19 years old and whose proximal femoral physis had not yet closed were matched to adult (20 to 40-year-old) counterparts in a 1:1 ratio by sex, body mass index, and time of surgery. For the adolescents, cam resection was performed with a physeal-sparing approach. Outcome scores, including the modified Harris hip score (mHHS), Hip Outcome Score-Activities of Daily Living (HOS-ADL), and HOS-Sports-Specific Subscale (HOS-SSS), were prospectively collected.

RESULTS

Of the 196 eligible adolescents, 157 (80%) were pair-matched to adult controls, with a median postoperative follow-up of 8.9 and 6.6 years, respectively. Fourteen (9%) of the adolescents required revision hip arthroscopy compared with 18 adults (11%) (p = 0.46). No patient in the adolescent group had conversion to a total hip arthroplasty (THA), while 3 in the adult group had a THA (p = 0.25). For adolescents without subsequent hip surgery, the median mHHS improved from 59 preoperatively to 96 postoperatively; the HOS-ADL, from 71 to 98; and the HOS-SSS, from 44 to 94 (p < 0.001), which were significantly higher postoperative scores than those of the matched adults (p < 0.05) despite similar or inferior baseline scores. No complications were found during the office visit or at the final follow-up.

CONCLUSIONS

Hip arthroscopy performed with a physeal-sparing approach for FAI in growing adolescents is safe and effective and yields superior clinical outcomes compared with those in a matched adult group.

LEVEL OF EVIDENCE

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

Edema of the Ligamentum Teres as a Novel MRI Marker for Non-Traumatic Painful Hip Pathology: A Retrospective Observational Study

Background

The ligamentum teres has been recognized as an important stabilizer of the hip joint and can be affected by various hip pathologies. This study aims to introduce ligamentum teres edema as an MRI marker to diagnose the underlying cause of hip pathology, mainly femoral acetabular impingement (FAI) and adult developmental dysplasia of the hip (ADDH), in non-traumatic patients.

Methodology

Adult patients presenting with non-traumatic hip pain of variable duration and ligamentum teres edema on MRI between 2014 and 2020 were included. A high-resolution standard MRI hip protocol was used for all patients in this series. MRI and plain radiographs were assessed. Ligamentum teres edema, alpha angle, center edge angle of Wiberg, and retroversion were assessed.

Results

In total, 55 patients with 110 hip joints (males: 29 (52.7%), females: 26 (47.3%)) of different ethnicities were included in this study. Out of the 55 patients with ligamentum teres edema, one had only unilateral right-sided FAI, seven had only unilateral left-sided FAI, and 46 (94 hip joints) had either bilateral FAI or ADDH. Therefore, eight (14.5%) patients with unilateral FAI had the absence of the contralateral FAI or ADDH (6.5% false-positive) despite the presence of ligamentum teres edema bilaterally, and the rest of the patients with bilateral ligamentum teres edema (102 joints: 92.7% positive predictive value) had findings of either FAI or ADDH.

Conclusions

Ligamentum teres edema can be considered as an early MRI marker to diagnose the underlying pathology of symptomatic painful hip disorders, especially FAI.

Treatment of Full-Thickness Acetabular Chondral Flaps During Hip Arthroscopy: Bone Marrow Aspirate Concentrate Versus Microfracture

Background:

The optimal treatment strategy for patients with full-thickness chondral flaps undergoing hip arthroscopy is controversial.

Purpose:

To compare functional outcomes of patients who underwent bone marrow aspirate concentrate (BMAC) application with those of patients who underwent microfracture.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This was a retrospective case series of prospectively collected data on patients who underwent arthroscopic acetabular labral repair by 1 surgeon between June 2014 and April 2020. The inclusion criteria for this study were age ≥18 years, preoperative radiographs of the pelvis, arthroscopic acetabular labral repair, exposed subchondral bone with overlying chondral flap seen at the time of hip arthroscopy, microfracture or BMAC to address this lesion, and completed patient-reported outcome measures (PROMs) (International Hip Outcome Tool–33 [iHOT-33], Hip Outcome Score–Activities of Daily Living [HOS-ADL], Hip Outcome Score–Sports Subscale [HOS-Sport], modified Harris Hip Score [mHHS], and visual analog scale [VAS] for pain) at enrollment and 12-month follow-up. Clinical outcomes were assessed using PROM scores.

Results:

A total of 81 hips with full-thickness chondral flaps were included in this study: 50 treated with BMAC and 31 treated with microfracture. There were no significant differences between groups in age, sex, body mass index, tear size, radiographic osteoarthritis, or radiographic femoroacetabular impingement. In the BMAC cohort, all PROM scores improved significantly from preoperatively to follow-up: 41.7 to 75.6 for iHOT-33, 67.6 to 91.0 for HOS-ADL, 41.5 to 72.3 for HOS-Sport, 59.4 to 87.2 for mHHS, and 6.2 to 2.2 for VAS pain (P < .001 for all). In the microfracture cohort, the score improvements were 48.0 to 65.1 for iHOT-33 (P = .001), 80.5 to 83.3 for HOS-ADL (P = .275), 59.2 to 62.4 for HOS-Sport (P = .568), 70.4 to 78.3 for mHHS (P = .028), and 4.9 to 3.6 for VAS pain (P = .036). Regarding clinically meaningful outcomes, 77.6% of the BMAC group and 50.0% of the microfracture group met the minimal clinically important difference for iHOT-33 at the 12-month follow-up (P = .013).

Conclusion:

Patients with full-thickness chondral flaps at the time of hip arthroscopy experienced greater improvements in functional outcome scores at the 12-month follow-up when treated with BMAC as opposed to microfracture.

Subspine Hypertrophy: Higher Incidence of Symptomatic versus Asymptomatic Hips in Patients with Unilateral Femoroacetabular Impingement

Objective

To compare the difference of anterior inferior iliac spine (AIIS) and subspine hypertrophic deformity between symptomatic and asymptomatic hips in patients traditionally diagnosed with femoroacetabular impingement (FAI), and investigate the correlation of subspine decompression with AIIS variation and subspine hypertrophic deformity.

Methods

We retrospectively reviewed 70 patients with unilateral symptomatic FAI who underwent hip arthroscopy. The operative hips and contralateral hips naturally formed the symptomatic groups and asymptomatic control groups, respectively. The morphometric comparison of the hip joint was performed between the operative and contralateral sides of each patient. Radiological assessment was performed by two observers (an experienced musculoskeletal radiologist and an experienced surgeon). Three‐dimensional (3D)‐CT images of each patient were blindly reviewed to determine the AIIS variation and subspine hypertrophic deformity. Reformatted two‐dimensional (2D)‐CT images and anterior–posterior (AP) pelvic plain radiographs were blindly reviewed to determine FAI‐related morphological measurements. Moreover, the surgical assessment was reviewed by one experienced surgeon to interpret whether subspine decompression was performed. The correlation of subspine decompression with AIIS variation and subspine hypertrophy was analyzed.

Results

Out of 70 patients with unilateral symptomatic FAI, 37 were males (52.9%) and 23 (32.9%) had symptoms involving the left hip. The mean age was 39.3 ± 10.4 years and the mean BMI was 24.3 ± 3.6. The distribution of AIIS variants in symptomatic hips did not differ significantly from that in asymptomatic hips (χ² = 3.092, P = 0.213). Twenty‐nine hips in the symptomatic group (41.4%) and 12 hips in the asymptomatic group (17.1%) were identified as positive for subspine hypertrophy. The incidence of positive subspine hypertrophy was significantly higher in the symptomatic hips compared to the asymptomatic hips (χ² = 9.968, P = 0.002). FAI‐related morphological parameters including α angle, lateral center‐edge angle, acetabular anteversion, crossover sign, and Tonnis grade were highly symmetrical and did not show significant differences between symptomatic and asymptomatic hips. Fifty‐four of 70 hips (77.1%) had labral tears extended to the acetabular rim corresponding to the AIIS. Forty‐seven hips of 70 hips (67.1%) underwent subspine decompression, which was significantly correlated with AIIS variation and subspine hypertrophic deformity (P = 0.019 and 0.001, respectively).

Conclusion

Subspine hypertrophic deformity was found to be more common in symptomatic side vs asymptomatic side in patients with unilateral symptomatic femoroacetabular impingement. Subspine hypertrophy may be considered as an underlying indication for subspine decompression besides low‐lying AIIS.

Mechanical stretching induces calcification and cartilage matrix metabolism, causing degeneration of the acetabular labrum

PURPOSE

The acetabular labrum plays an important role in joint lubrication, and damage to this structure leads to osteoarthritis. This study aimed to histologically classify the degree of degeneration of the acetabular labrum and to investigate the changes in gene expression induced by mechanical stretching.

METHODS

We obtained acetabular labrum cells from patients with hip osteoarthritis during total hip arthroplasty (n = 25). The labrum was stained with safranin O, and images were histologically evaluated using a new parameter, the red/blue (R/B) value. The samples were divided into the degenerated group (D group: n = 18) and the healthy group (H group: n = 7) in accordance with the Kellgren-Lawrence (KL) grade. The cultured acetabular labral cells were subjected to loaded uniaxial cyclic tensile strain (CTS). After CTS, changes in gene expression were examined in both groups.

RESULTS

Spearman's correlation analysis revealed that the R/B value was significantly correlated with the KL grade and the Krenn score. The expression levels of genes related to cartilage metabolism, osteogenesis and angiogenesis significantly increased after CTS in the H group, while gene expression in the D group showed weaker changes after CTS than that in the H group compared to the nonstretched control group.

CONCLUSIONS

The degree of labral degeneration could be classified histologically using the R/B value and the KL grade. Mechanical stretching caused changes in gene expression that support the pathological features of labral degeneration.

Arthroscopic Approach to Preservation of the Hip with Avascular Necrosis

Avascular necrosis (AVN) of the hip is a devastating disease that affects middle-aged adults with poor outcomes if not treated in its early stages. In recent years, subchondroplasty with calcium phosphate solution has shown promising results. Concomitant intra-articular pathologies, including femoroacetabular impingement and chondral lesions, have been described in hips affected by AVN. These should be addressed at the time of surgery to lower the risk of failure. In this Technical Note, we describe an arthroscopic approach to femoral head subchondroplasty with precollapse lesion in AVN affected hip, combined with labral reconstruction and acetabular chondral treatment.

Arthroscopic Treatment of Femoroacetabular Impingement in Patients With and Without Borderline Developmental Dysplasia of the Hip: A Systematic Review and Meta-analysis

Background:

Based on previous studies, it is difficult to discern whether patients who have femoroacetabular impingement (FAI) with borderline developmental dysplasia of the hip (BDDH) would benefit from arthroscopy when compared with patients without BDDH.

Purpose:

To evaluate the existing comparative literature on arthroscopic findings, procedures, patient-reported outcomes (PROs), and failures in patients who have FAI with BDDH compared with those without BDDH.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

The PubMed, Embase, and Ovid databases were searched for studies published up to August 31, 2019, that reported outcomes after arthroscopy to treat patients who had FAI with BDDH. Included studies were required to have patients diagnosed with FAI and BDDH who were treated arthroscopically and compared with control patients (FAI without BDDH). Arthroscopic findings, PROs, and revision or total hip arthroplasty (THA) conversion rates were compared between groups.

Results:

Included in the review were 4 articles (933 patients). Patients who had FAI with BDDH were defined as having a lateral center-edge angle (LCEA) of either 18° to 25° or 20° to 25°; for control patients, the maximum LCEA was 40°. Across the studies, there were 224 patients who had FAI with BDDH compared with 709 control patients; the mean follow-up time ranged from 21.6 to 31.3 months among the groups. Improvements were shown across all PROs in each study. Random-effects meta-analysis indicated no statistically significant differences in postoperative PROs, the risk for revision surgery, or conversion to THA between the patients who had FAI with versus without BDDH.

Conclusion:

The results of the current review indicated that hip arthroscopy produced similar short-term outcomes between patients who had FAI with versus without BDDH.

Three-dimensional motion analysis of ten common Asian sitting positions in daily living and factors affect range of hip motions

BACKGROUND

Sitting involves many activities of daily life and requires most motion in the hip joint. Asians have more hip flexion and external rotation motions than Westerners owing to cultural and lifestyle differences. Being aware of the normal range of hip motion is essential in clinical practice. Limited research has focused on the hip motions of common sitting positions. The objective was to determine the hip motions of 10 common sitting positions, and to determine whether gender or being overweight affects the range of hip motions.

METHODS

An experimental cross-sectional study was conducted to determine hip motions by using a standard, three-dimensional, motion-analysis system. Healthy subjects performed 10 sitting positions during 3 trials. All hip-kinematic data were measured on the dominant leg of each participant, except for the right- and left-monk positions (both hips were analyzed). Density plots were constructed and statistical analyses were performed to detect the differences between groups (male and female; non-overweight and overweight).

RESULTS

The 48 participants comprised 24 males and 24 females. Most were right-leg dominant (45 participants, 93.8%). Of the 22 participants in the overweight group (body mass index ≥23 kg/m²), 18 (75%) were male. Squatting showed the highest flexion angle (99.7°, 47.3°-122°). Cross-legged sitting had the highest abduction angle (28.9°, 9.9°-45.7°) and the largest external rotation angle (62°, 37.6°-81.7°). In the female group, there were trends toward a greater flexion angle (4 out of 10 sitting positions) and a smaller abduction angle (6 out of 9 positions), with P values < 0.05. As to body weight, the overweight participants had a smaller flexion angle but a greater abduction angle, with 5 out of 9 positions having a P value < 0.05. Kinematic data of the transverse plane revealed that the heterogeneity of the rotational angles depended on the sitting position.

CONCLUSIONS

This study provided the functional hip motions of common Asian sitting positions. The kinematic data can be utilized in clinical practice as reference values to determine safe positions. Gender and being overweight affected the hip angles in the sagittal and frontal planes.

TRIAL REGISTRATION

Number TCTR20181021004 , retrospectively registered at the Thai Clinical Trials Registry (http//:www.clinicaltrials.in.th).

Sex differences in the prevalence of radiographic findings of structural hip deformities in patients with symptomatic femoroacetabular impingement

The purpose of this study was to determine the sex differences in the overall prevalence of radiographic femoroacetabular impingement (FAI) deformity patients presenting with hip pain and to identify the most common radiographic findings in male and female patients. A geographic database was used to identify patients between the age of 14 and 50 years with hip pain from 2000 to 2016. A chart and radiographic review was performed to identify patients with cam, pincer and mixed-type FAI. A total of 374 (449 hips) out of 612 (695 hips) male patients and 771 (922 hips) out of 1281 (1447 hips) female patients had radiographic features consistent with FAI. Ninety-four male hips (20.9%) and 45 female hips (4.9%) had cam type, 20 male hips (4.5%) and 225 female hips (24.4%) had pincer type and 335 male hips (74.6%) and 652 female hips (70.7%) had mixed type. The overall prevalence of radiographic findings consistent with FAI in male and female patients with hip pain was 61.1% and 60.2%, respectively. Mixed type was the most prevalent. The most common radiographic finding for cam-type FAI was an alpha angle >55°, and the most common radiographic finding for pincer-type FAI was a crossover sign. Male patients were found to have a higher prevalence of cam-type deformities, whereas female patients were found to have a higher prevalence of pincer-type deformities.

Arthroscopic Treatment for Femoroacetabular Impingement Syndrome with External Snapping Hip: A Comparison Study of Matched Case Series

OBJECTIVE

To determine the effectiveness of hip arthroscopy combined with endoscopic iliotibial band (ITB) release in patients with both femoroacetabular impingement (FAI) syndrome and external snapping hip (ESH).

METHODS

Retrospectively review the preoperative and minimum of 2-year follow-up data of patients with both FAI syndrome and ESH who underwent endoscopic ITB release during hip arthroscopy (FAI + ESH group) from January 2014 to December 2018. The same number of age- and gender-matched FAI syndrome patients without ESH undergoing hip arthroscopy were enrolled in the control group (FAI group). Patient-reported outcomes (PROs) including international Hip Outcome Tool (iHOT-33), modified Harris Hip Score (mHHS), visual analog scale for pain (VAS-pain), and abductive force of affected hip at 3 month and 2 years postoperatively were comparatively analyzed. The VAS-satisfaction score of two groups at 2 years postoperatively were also analyzed.

RESULTS

The prevalence of ESH in FAI syndrome patients undergoing hip arthroscopy in our institution was 5.5% (39 of 715 hips), including nine males (10 hips) and 29 females (29 hips). The mean age at the time of surgery was 32.1 ± 6.9 years (range, 22-48 years). According to inclusion and exclusion criteria, 23 patients were enrolled in FAI + ITB group. Twenty-three age- and sex-matched FAI syndrome patients were enrolled in FAI group. At 24 months postoperatively, no patient still suffered ESH symptoms and painful palpation at lateral region in FAI + ITB group. The iHOT-33, mHHS, and VAS-pain score of patients in FAI + ESH group were significantly severer than patients in FAI group preoperatively (41.6 ± 7.5 vs 48.8 ± 7.2, 54.8 ± 7.2 vs 59.2 ± 6.9, 5.5 ± 0.9 vs 4.7 ± 1.0; P < 0.05), while there was no significant difference in these scores between the patients in FAI + ESH group and FAI group at 3-month and 24-month follow-up (73.6 ± 8.5 vs 76.1 ± 6.9, 85.3 ± 7.8 vs 84.2 ± 6.6, 0.8 ± 0.9 vs 0.6 ± 0.9; P > 0.05). At 3 months after surgery, the abductive force of operated hip was significantly smaller than that in FAI group (82.4 ± 12.4 N vs 91.9 ± 16.1 N, P < 0.05), whereas there was no significant difference at 24 months after surgery (101.6 ± 14.9 N vs 106.5 ± 13.7 N, P > 0.05). The VAS-satisfaction scores of patients in the two groups were at a similarly high level (90.5 ± 6.8 vs 88.8 ± 7.3, P > 0.05). There was no complication and no arthroscopic revision in either group until 2-year follow-up.

CONCLUSION

Although abductive force recovery of the hip was delayed, hip arthroscopy combined with endoscopic ITB release addressed hip snapping in patients with both FAI syndrome and ESH, and could get similar functional improvement, pain relief, recovery speed, as well as patient satisfaction compared with the pure hip arthroscopy in FAI syndrome patients without ESH.

Femoracetabular impingement treated with surgical hip dislocation: Short-term results

BACKGROUND AND OBJECTIVE

Most of the studies available in the literature related to the treatment of femoroacetabular impingement (FAA) with surgical hip dislocation (CLD) come from Europe and North America. This study describes the short-term results of the LQC technique for treating PFA in a cohort of Colombian patients.

PATIENTS AND METHODS

We retrospectively analysed 42 cases of PFA treated with LQC from 2006 to 2018. The same orthopaedic surgeon performed all surgeries. Clinical outcome was assessed using the Merle d'Aubigné scores, while radiological assessment was performed using the Tönnis score.

RESULTS

Fifteen women and 25 men were included in the study, with a mean age of 36.3 years. Two patients had bilateral symptomatic involvement. Of the 42 cases, there were 13 cam type, 11 pincer type and 18 mixed. Preoperatively, 31 hips were classified as poor and moderate, and 11 as good according to the Merle d'Aubigné scale. The preoperative Tönnis radiological classification showed grade 0 in half of the cases. The mean duration of follow-up was 24 months (12 to 37). The final postoperative Merle d'Aubigné scores classified 7 cases as poor or moderate, and 35 as good to excellent (p<0.05). The postoperative Tönnis score showed no significant variation. As complications, one patient had heterotopic ossification, and three had trochanteric nonunion requiring refixation.

CONCLUSION

Our results suggest that the LQC technique for the treatment of patients with PFA shows satisfactory short-term results with a low complication rate. To our knowledge, this is the first report of results of the surgical procedure for hip dislocation in our region.

Femoroacetabular Impingement of the Hip Joint – Literature Review

Introduction: In patients with painful hip joint, femoroacetabular impingement is a relatively frequently diagnosed condition. Study aim: The aim of the study was to present the anatomy, biomechanics and pathomechanism of femoroacetabular impingement, surgical diagnostics and treatment, as well as physiotherapeutic procedures, and to provide answers to the following questions: 1. What are the causes of femoroacetabular impingement development and what is its most common form? 2. What are the clinical and imaging diagnosis of femoroacetabular impingement based on? 3. What are the goals of physiotherapeutic treatment in the treatment of patients with postoperative femoroacetabular impingement? Material and method: Current professional literature was analysed based on a review of Internet databases, including Pubmed and Google Scholar. Results: From the abovementioned Internet databases, 30 items from the current profession-al literature on the analysed variables were identified. Conclusions: The reasons for the development of femoroacetabular impingement are com-plex, including developmental disorders of the hip joint or its chronic overload. Its most common form is mixed type. The basic imaging test used is anterior-posterior X-ray, while clinical assessment is based on anterior-posterior impingement test. Physiotherapy should be individually tailored and focused on improving range of motion and muscle strength of the hip joint.

Increased range of motion but otherwise similar clinical outcome of arthroscopy over open osteoplasty for femoroacetabular impingement at midterm follow-up: A systematic review

BACKGROUND

A systematic review was conducted comparing patient reported outcomes measures (PROMs), functional scores, and the rate of complications between arthroscopic and open treatment for femoroacetabular impingement (FAI) at mid-term follow-up.

MATERIAL AND METHODS

This systematic review was performed according to the PRISMA guidelines. The literature search was performed in October 2020. All clinical trials treating FAI using open osteoplasty or arthroscopic surgery were considered for inclusion. Only articles reporting >12 months follow-up were included.

RESULTS

Data from 97 articles (9981 procedures) were collected. At a mean 19.2 months follow-up there was no difference between the two cohorts. At a mean follow-up of 38 months, the external rotation was increased in the arthroscopic group (P < 0.0001). The modified Harris Hip Score scored greater in favour of the open osteoplasty group (P = 0.04), as did the Hip Outcome Score - Activities of Daily Living subscale (P = 0.01). At a mean 45.1 months the arthroscopic group presented greater external rotation (P < 0.0001) and SF-12 Mental (P = 0.04). The modified Harris Hip Score was greater in favour of the open osteoplasty group (P = 0.03), as was the HOS-ADL (P = 0.01). Regarding complications, the arthroscopic group experienced lower rates of subsequent revisions (P < 0.0001).

CONCLUSION

Based on the significant reduction of revisions-rate and significant increase in range of motion, arthroscopy treatment for the management of FAI may be recommended.

Functional Condition of Patients after Unilateral Hip Arthroscopy in the Process of FAI-Femoroacetabular Impingement: A Case-Control Study and Preliminary Report

Introduction: Femoroacetabular impingement is a commonly recognized condition among people with hip pain. Aim: The aim of this study was to assess how arthroscopy and physiotherapy treatment influenced the quality of life and functional condition of patients after arthroscopic femoroacetabular impingement (FAI) surgery. Materials and methods: We examined 19 people for the study and included 12 (6 men and 6 women). Their mean age was 40.1 ± 9.7 years. Manual and digital goniometers were used for the range of motion (ROM) measurements, and a dynamometer for muscle strength was used. Results from the operated limb were compared to the nonoperated healthy limb. We examined the patient’s health and well-being using the Harris Hip Score (HHS) and Short-Form Health Survey (SF-36) scales. The mean follow-up period was 21.2 months. Results: The postsurgery mean range of motion for all movements was lower in the operated limb. Statistically significant differences between limbs in ROM were observed for flexion, abduction, extension, and external rotation. Muscle strength was comparable between hip joints, except extension and adduction, which were statistically significantly weaker. The mean strength of the hip flexors and internal rotators was higher in the operated limb. After surgery, 67% of patients returned to exercise at the same or higher level. The mean HHS results were good, with values of 88.00 ± 11.48. The SF-36 scores were >50. Conclusion: After surgery and physiotherapy of FAI, ROM remained lower in the operated limb. Flexion and rotations remained to cause pain. The strength of flexors and internal rotators improved, and there was a high rate of return to sport.

FUNCTIONAL OUTCOMES OF ARTHROSCOPIC TREATMENT IN 230 FEMOROACETABULAR IMPINGEMENT CASES

Objective:

To analyze the functional outcomes after arthroscopic treatment of femoroacetabular impingement (FAI).

Methods:

194 patients (131 males and 63 females), with a mean age of 39 (15-68) years old for men and 43 (16-58) years old for women. The average follow-up was 17 months (2 to 71). 103 patients presented Cam-type FAI, 102 mixed and 25 Pincer. “Unilateral” arthroscopy was performed in 161 cases, “Bilateral” (only once each side) in 46 cases and, “Multiple” (more than one procedure on the same hip) in 23. The female sex was prevalent in the Pincer type FAI (76%), while males were prevalent in Mixed and Cam type, 74.5% and 72.8%, respectively.

Results:

The mean HHSpre score was 63.7 and 87.1 for HHSpost, i.e. 73.11%. Differences appeared between “mixed” and “unilateral” groups. The complications percentage in this series was 18.7% and 7% progressed to total hip arthroplasty.

Conclusion:

The arthroscopic FAI treatment improved the postoperative clinical scores of these patients, especially in cases of mixed-type FAI, which presented a higher improvement rate. Insufficient femoral osteoplasty was the main cause for surgical re-intervention, particularly in the initial cases of this series. Level of Evidence II, Retrospective study.

Accurate Arthroscopic Cam Resection Normalizes Contact Stresses in Patients With Femoroacetabular Impingement

BACKGROUND

Femoroacetabular impingement (FAI) is increasingly recognized as a cause of hip pain in young adults. The condition leads to chondrolabral separation and chondral delamination and eventually predisposes to osteoarthritis of the hip. FAI that inflicts cartilage damage has been observed in hips with abnormal morphological characteristics and is related to a long-term evolution toward osteoarthritis. Arthroscopic surgery, which allows for correction of morphological characteristics and restores impingement-free motions, is the current standard of treatment.

HYPOTHESIS

Arthroscopic cam resection can restore the normal mechanical environment of the hip joint in cam-type FAI.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Patient-specific discrete element models from 10 patients with cam-type FAI (all male; age, 18-40 years) were defined based on preoperative computed tomography scans and postoperative magnetic resonance imaging (MRI) scans. Complete cam resection postoperatively on MRI was confirmed with alpha angles <55°. The preoperative and postoperative peak contact stress findings during impingement testing were compared against a matched control group.

RESULTS

Peak contact stress was significantly elevated in patients with cam-type FAI during impingement testing, with increasing amounts of internal hip rotation (26.6 ± 11.64 MPa in cam patients preoperatively, 12.1 ± 4.62 MPa in those same patients postoperatively, and 11.4 ± 1.72 MPa in the virtual control group during impingement testing at 20° of internal hip rotation; P < .01). This effect was normalized after arthroscopic cam resection and loading patterns matched those of the control group.

CONCLUSION

Accurate arthroscopic cam resection restored the normal peak joint contact stresses in the hip joint. This highlights the importance of early and complete cam resections in the face of a positive diagnosis of cam-type FAI.

CLINICAL RELEVANCE

Treatment of cam-type FAI effectively normalizes hip joint contact mechanics.

Image quality of hip MR arthrography with intra-articular injection of hyaluronic acid versus gadolinium-based contrast agent in patients with femoroacetabular impingement

OBJECTIVE

To compare image quality of magnetic resonance arthrography (MRA) of the hip with intra-articular injection of high-viscosity hyaluronic acid (HA-MRA) versus Gd-based contrast agent (Gd-MRA) in patients with femoroacetabular impingement (FAI).

MATERIALS AND METHODS

Design: single-centre, observational, retrospective, inter-individual, and cross-sectional. FAI patients who underwent HA-MRA (3 mL of high-viscosity HA plus 17 mL of saline) were compared with 37 age- and sex-matched FAI patients who underwent Gd-MRA (20 mL of 2 mmol/L solution of gadopentetate dimeglumine). Two independent blinded radiologists assessed image quality for all sequences (two-dimensional proton density, non-fat-sat axial, fat-sat coronal and sagittal; three-dimensional dual-echo steady state), using a 5-point Likert scale considering separately labrum, cartilage, round ligament, transverse ligament, and capsule. Pearson χ² and Cohen κ were used.

RESULTS

The HA-MRA group was composed of 37 patients (23 males, 14 females; median age 38 years), the Gd-MRA group of 37 patients (21 males, 16 females; median age 38 years), without significant difference for age (p = 0.937) and sex (p = 0.636). Image quality did not differ between the two readers for any structure: labrum (p ≥ 0.340), cartilage (p ≥ 0.198), round ligament (p ≥ 0.255), transverse ligament (p ≥ 0.806), and capsule (p ≥ 0.314). Inter-reader agreement (κ) ranged from 0.785 to 1.000.

CONCLUSIONS

HA-MRA provided an image quality not significantly different from that of Gd-MRA. This may open the possibility of combining MRA and viscosupplementation in one single procedure.

Pathomechanics Underlying Femoroacetabular Impingement Syndrome: Theoretical Framework to Inform Clinical Practice

Over the last decade, there has been a marked increase in attention to, and interest in, femoroacetabular impingement syndrome (FAIS). Despite continued efforts by researchers and clinicians, the development, progression, and appropriate treatment of FAIS remains unclear. While research across various disciplines has provided informative work in various areas related to FAIS, the underlying pathomechanics, time history, and interaction between known risk factors and symptoms remain poorly understood. The purpose of this perspective is to propose a theoretical framework that describes a potential pathway for the development and progression of FAIS. This paper aims to integrate relevant knowledge and understanding from the growing literature related to FAIS to provide a perspective that can inform future research and intervention efforts.

Expression profile of matrix metalloproteinases in the labrum of femoroacetabular impingement

Aims

Femoroacetabular impingement (FAI) is a potential cause of hip osteoarthritis (OA). The purpose of this study was to investigate the expression profile of matrix metalloproteinases (MMPs) in the labral tissue with FAI pathology.

Methods

In this study, labral tissues were collected from four FAI patients arthroscopically and from three normal hips of deceased donors. Proteins extracted from the FAI and normal labrums were separately applied for MMP array to screen the expression of seven MMPs and three tissue inhibitors of metalloproteinases (TIMPs). The expression of individual MMPs and TIMPs was quantified by densitometry and compared between the FAI and normal labral groups. The expression of selected MMPs and TIMPs was validated and localized in the labrum with immunohistochemistry.

Results

On MMP arrays, most of the targeted MMPs and TIMPs were detected in the FAI and normal labral proteins. After data normalization, in comparison with the normal labral proteins, expression of MMP-1 and MMP-2 in the FAI group was increased and expression of TIMP-1 reduced. The histology of the FAI labrum showed disorderly cell distribution and altered composition of thick and thin collagen fibres. The labral cells expressing MMP-1 and MMP-2 were localized and their percentages were increased in the FAI labrum. Immunohistochemistry confirmed that the percentage of TIMP-1 positive cells was reduced in the FAI labrum.

Conclusion

This study established an expression profile of MMPs and TIMPs in the FAI labrum. The increased expression of MMP-1 and MMP-2 and reduced expression of TIMP-1 in the FAI labrum are indicative of a pathogenic role of FAI in hip OA development.

Cite this article:Bone Joint Res. 2020;9(4):173–181.

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.

The Prevalence of Radiographic Findings of Structural Hip Deformities for Femoroacetabular Impingement in Patients With Hip Pain

BACKGROUND

Radiography is the initial imaging modality used to evaluate femoroacetabular impingement (FAI), and diagnostic radiographic findings are well-established. However, the prevalence of these radiographic findings in patients with hip pain is unknown.

PURPOSE

The purpose was 3-fold: (1) to determine the overall prevalence of radiographic FAI deformities in young patients presenting with hip pain, (2) to identify the most common radiographic findings in patients with cam-type FAI, and (3) to identify the most common radiographic findings in patients with pincer-type FAI.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A geographic database was used to identify patients aged 14 to 50 years with hip pain between the years 2000 to 2016. The following were evaluated on radiographs: cam type: typical pistol grip deformity, alpha angle >55°; pincer type: crossover sign (COS), coxa profunda or protrusio acetabuli, lateral center edge angle (LCEA) ≥40°, Tönnis angle <0°; and mixed type: both cam- and pincer-type features. Posterior wall sign (PWS) and ischial spine sign (ISS) were also evaluated. The prevalence of each was determined. Descriptive statistics were performed on all radiographic variables.

RESULTS

There were 1893 patients evaluated, and 1145 patients (60.5%; 1371 hips; 374 male and 771 female; mean age, 28.8 ± 8.4 years) had radiographic findings consistent with FAI. Of these hips, 139 (10.1%) had cam type, 245 (17.9%) had pincer type, and 987 (72.0%) had mixed type. The prevalence of a pistol grip deformity and an alpha angle >55° was 577 (42.1%) and 1069 (78.0%), respectively. The mean alpha angle was 66.9°± 10.5°. The prevalence of pincer-type radiographic findings was the following: COS, 1062 (77.5%); coxa profunda, 844 (61.6%); ISS, 765 (55.8%); PWS, 764 (55.7%); Tönnis angle <0°, 312 (22.8%); LCEA ≥40°, 170 (12.4%); and protrusio acetabuli, 7 (0.5%).

CONCLUSION

The overall prevalence of radiographic findings consistent with FAI in young patients with hip pain was 60.5%. Radiographic findings for mixed-type FAI were the most prevalent. The most common radiographic finding for cam-type FAI was an alpha angle >55°. The most common radiographic finding for pincer-type FAI was the COS.

Corrections in alpha angle following two different operative approaches for CAM-type femoral acetabular impingement - Ganz surgical hip dislocation vs anterior mini-open

BACKGROUND

Femoroacetabular impingement (FAI) is a predisposing factor for secondary osteoarthritis of the hip joint. The two extensively described impingement mechanisms of FAI are CAM and Pincer-type. Initially managed conservatively, operative intervention should be offered to the persistently symptomatic patient. The measurement of the alpha angle is considered a standard method of assessing the severity of pathology in Cam-type FAI on pre-operative plain radiographs. The radiological correction of the alpha angle has not been previously compared between different surgical approaches. We hypothesize that there is no difference in alpha angle correction between Ganz surgical hip dislocation and the anterior mini-open approach.

AIM

To compare the magnitude of alpha angle correction achieved by using the Ganz surgical hip dislocation and the anterior mini-open approach.

METHODS

This is a retrospective study assessing seventy-nine patients identified in a 5-year period. These patients had preoperative radiographic evidence of FAI and underwent surgery by a single surgeon at our institution, a tertiary care center. Patients with missing radiographic documentation, radiographs with insufficient quality which then precluded accurate measurement of the angle α, a diagnosed congenital condition, isolated type II pathology (Pincer), and history of prior surgery were excluded from the study. Either the Ganz surgical hip dislocation or the anterior mini open approach was used. Postoperative radiographic evaluation of the alpha angle between the two surgical methods was done and corrected for age and gender using two-sample t-tests and Chi-square analyses.

RESULTS

A total of 79 patients met the inclusion and exclusion criteria. Forty-seven males (mean age of 35.3, range 16-53) and 32 females (mean age 36.7, range 16-60) were enrolled. Forty-seven patients underwent the anterior mini-open approach, and 32 underwent the Ganz surgical hip dislocation. There were no significant differences in age between the two surgical groups or in pre- and post-operative alpha angles based on patient gender. The mean pre-operative alpha angle for the Ganz surgical hip dislocation group was 88.0 degrees (SD 12.3) and 99.4 degrees (SD 7.2) for the anterior mini-open group. Mean post-operative angles were 49.9 degrees (SD 4.3) for the Ganz surgical hip dislocation and 43.8 (SD 4.3) degrees for the anterior mini-open group. There was a statistically significant difference in patient’s pre-operative and post-operative angles (P = 0.000) with both surgical approaches.

CONCLUSION

Statistically significant decreases in alpha angle were noted for both surgical techniques, with larger decreases seen in the anterior mini-open group.

Magnetic Resonance Arthrography, a valuable pre-operative imaging modality in femoro-acetabular impingement

Background

The diagnostic accuracy of MR arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients.

A non-randomized control study including 31 FAI patients (17 male and 14 females, mean age 31.9 years). All patients underwent MR arthrography after US-guided intra-articular contrast injection. Conventional and MR arthrography images were evaluated for bone abnormalities (including alpha angle and acetabular depth measurements), labral tears, and chondral abnormalities. The results were correlated to arthroscopy as the gold standard. Sensitivity, specificity, PPV, and NPV in the detection of labral tears and chondral abnormalities were statistically calculated.

Results

The included FAI patients presented cam (mean age 30.4 years ± 6.8 years), pincer (mean age 33.6 years ± 9.8 years), and mixed (mean age 36.6 years ± 12.9 years) types with the predominance of cam type. Cam type predominated in the male, while pincer and mixed types predominated in female patients. MR arthrography detected 41 labral tears in 23 patients with 87.5%, 71.4%, 91.3%, and 62.5% sensitivity, specificity, PPV, and NPV, respectively, and detected chondral abnormalities in 13 patients with 66.7%, 92.3%, 92.3%, and 66.7% sensitivity, specificity, PPV, and NPV, respectively.

Conclusion

MR arthrography is a valuable imaging modality in preoperative assessment of FAI patients. Besides identifying the type of impingement through alpha angle and acetabular depth measurements, it detects labral tears with high sensitivity and PPV. Although less sensitive in detection of chondral abnormalities, our results showed high specificity.

Efficacy of preemptive analgesia versus postoperative analgesia of celecoxib on postoperative pain, patients' global assessment and hip function recovery in femoroacetabular impingement patients underwent hip arthroscopy surgery

We aimed to investigate the efficacy of preemptive analgesia of celecoxib on postoperative pain, patients' global assessment (PGA) and hip function recovery compared to postoperative analgesia of celecoxib in femoroacetabular impingement (FAI) patients who underwent hip arthroscopy surgery (HAS). The 100 FAI patients underwent HAS were randomly allocated to preemptive analgesia group (N = 50) or postoperative analgesia group (N = 50) as a 1:1 ratio for 3 months. Pain visual analog scale (VAS) score, PGA score, rescue-use pethidine consumption and Harris hip score were assessed. Compared to postoperative analgesia group, pain VAS score decreased on day 1 (P = 0.036), day 2 (P = 0.046) and day 3 (P = 0.046), while was similar prior to operation (P = 0.587), on day 7 (P = 0.398), at month 1 (P = 0.461) and month 3 (P = 0.805) in preemptive analgesia group. Besides, rescue-use pethidine consumption was decreased in preemptive analgesia group than postoperative analgesia group within 3 days (P = 0.016) and within 7 days (P = 0.033) post-operation. For PGA score, it reduced on day 2 (P = 0.030) and day 3 (P = 0.048), while was similar prior to operation (P = 0.699), on day 1 (P = 0.699), day 7 (P = 0.224), at month 1 (P = 0.640) and month 3 (P = 0.400) in preemptive analgesia group than postoperative analgesia group. For Harris hip score, it was similar prior to operation (P = 0.372), on day 7 (P = 0.366), at month 1 (P = 0.466) and month 3 (P = 0.658) between the two groups. In conclusion, preemptive analgesia of celecoxib decreases short-term postoperative pain and PGA, but without effect on long-term hip function recovery than postoperative analgesia of celecoxib in FAI patients who underwent HAS.

Predictors of chronic prescription opioid use after orthopedic surgery: derivation of a clinical prediction rule

Background

Prescription opioid use at high doses or over extended periods of time is associated with adverse outcomes, including dependency and abuse. The aim of this study was to identify mediating variables that predict chronic opioid use, defined as three or more prescriptions after orthopedic surgery.

Methods

Individuals were ages between 18 and 50 years and undergoing arthroscopic hip surgery between 2004 and 2013. Two categories of chronic opioid use were calculated based on individuals (1) having three or more unique opioid prescriptions within 2 years and (2) still receiving opioid prescriptions > 1 year after surgery. Univariate elationships were identified for each predictor variable, then significant variables (P > 0.15) were entered into a multivariate logistic regression model to identify the most parsimonious group of predictor variables for each chronic opioid use classification. Likelihood ratios were derived from the most robust groups of variables.

Results

There were 1642 participants (mean age 32.5 years, SD 8.2, 54.1% male). Nine predictor variables met the criteria after bivariate analysis for potential inclusion in each multivariate model. Eight variables: socioeconomic status (from enlisted rank family), prior use of opioid medication, prior use of non-opioid pain medication, high health-seeking behavior before surgery, a preoperative diagnosis of insomnia, mental health disorder, or substance abuse were all predictive of chronic opioid use in the final model (seven variables for three or more opioid prescriptions; four variables for opioid use still at 1 year; all< 0.05). Post-test probability of having three or more opioid prescriptions was 93.7% if five of seven variables were present, and the probability of still using opioids after 1 year was 69.6% if three of four variables were present.

Conclusion

A combination of variables significantly predicted chronic opioid use in this cohort. Most of these variables were mediators, indicating that modifying them may be feasible, and the potential focus of interventions to decrease the risk of chronic opioid use, or at minimum better inform opioid prescribing decisions. This clinical prediction rule needs further validation.

Position of the Hip in Yoga

BACKGROUND

Yoga is growing in popularity as a form of exercise throughout the world. Orthopedic patients participate in yoga, yet little is known about the ranges-of-motion of the hip within various yoga poses. Orthopedic surgeons are unsure about what potential positions their patients are placing their hips during a yoga practice. The aim of this study is to quantify the degree of hip motion with common yoga poses.

METHODS

Twenty healthy, regular practitioners of yoga performed 11 different yoga poses in a standardized fashion. Motion analysis was used to capture range-of-motion of the hip during each pose.

RESULTS

Many yoga poses put the hip in extremes of motion. Poses such as downward dog, forward fold, seated twist, and pigeon stressed the hip in flexion. Warrior 1, warrior 2, crescent lunge, pigeon, and triangle stressed the hip in extension. Eagle and seated twist put the hip in higher adduction, while half moon, eagle, and triangle produced more hip internal rotation.

CONCLUSION

Many poses were found to reach extremes of hip motion. This study may help guide the orthopedic surgeon in counseling hip arthroplasty and hip impingement patients about yoga-related activity. By knowing which poses potentially stress the hip in particular planes of motion, surgeons may better inform their patients who are returning to yoga after injury or surgery.