Adolescent femoroacetabular impingement from malunion of the anteroinferior iliac spine apophysis treated with arthroscopic spinoplasty

Apophyseal ilium avulsion fractures in young athletes: a systematic review and return to sport analysis

The purpose of the current investigation was to synthesize the epidemiology, cause, management, and return to sport (RTS) outcomes of ilium avulsion fractures sustained during sporting activities in young athletes. Studies reporting on athletes <18 years old sustaining an avulsion fracture along the ilium [injury to the anterior superior or inferior iliac spine (ASIS or AIIS), or the iliac crest (IC)], and the athlete's RTS status were included. RTS was analyzed by injury acuity, location, mechanism of injury, and management, whereas complications were recorded. Seventy studies comprising 286 avulsions (169 ASIS, 87 AIIS, and 30 IC) were included. The mean age of athletes was 14.5 + 1.3 years (range, 8-18 years). Sprinting (n = 103/286; 36.0%) and soccer (n = 97/286; 33.9%) were the most common sports during which injuries occurred. A total of 96.5% (n = 276/286) of athletes reported successful RTS at an average of 16.2 + 19.3 weeks. The RTS rate for patients sustaining ASIS, AIIS, and IC avulsions was 95.3, 97.7, and 100%, respectively. Acute trauma was responsible for 89.8% (n = 158/176) of injuries, which demonstrated a significantly faster (13.3 + 9.3 weeks) and higher RTS rate (99.4%) compared with those with chronic avulsions (74.4 + 40.9 weeks and 83.3%, respectively). Those with complications (18.2%) had a significantly lower RTS rate (90.4%) and longer recovery (23.7 weeks) compared with athletes without complications (97.9% and 14.5 weeks, respectively). Outcomes were not significantly different based on sex or management. However, chronic avulsions and postoperative complications sustained worse RTS results. An accurate and timely diagnosis is crucial when presented with these rare injuries to avoid increasing the chronicity of injury.

Acute Pelvic and Hip Apophyseal Avulsion Fractures in Adolescents: A Summary of 719 Cases

BACKGROUND

Apophyseal avulsion fractures of the pelvis and hip are common injuries in adolescent athletes. However, high volume comparative studies elucidating the spectrum of injuries are largely absent from the literature. The current study provides a comprehensive analysis of demographic, anatomic, pathophysiological, clinical, and athletic-related variables associated with such injuries in an extensive population of affected adolescents.

METHODS

A retrospective review was performed of records of patients presenting to a single tertiary care pediatric hospital between January 1, 2005, and July 31, 2020, collecting variables including patient sex, age, body mass index, fracture location, injury mechanism, sport at the time of injury, and duration of prodromal symptoms.

RESULTS

Seven hundred nineteen fractures were identified in 709 patients. The average patient age was 14.6, and 78% of the fractures occurred in male patients. The anterior inferior iliac spine (33.4%), anterior superior iliac spine (30.5%), and ischial tuberosity (19.4%) were the most common fracture sites. The most common injury mechanisms were running (27.8%), kicking (26.7%), and falls (8.8%). The most common sports at the time of injury were soccer (38.1%), football (11.2%), and baseball (10.5%). Fracture site was significantly associated with patient sex, age, body mass index, laterality, mechanism, sport, time from injury, and presence of prodromal symptoms. The annual volume of pelvic avulsion fractures treated at the institution increased significantly from n=17 in 2005 to n=75 in 2019.

CONCLUSIONS

Adolescent pelvic and hip avulsion fractures occur during a narrow window of age and skeletal maturation and are frequently sustained during sporting activities. Each fracture location is associated with certain demographic, mechanistic, and patient-specific characteristics. The associations between fracture site and patient-specific or injury-specific variables offer insights into the pathophysiology and possible underlying biomechanical risk factors that contribute to these injuries.

LEVEL OF EVIDENCE

This is a level III retrospective study.

Outcomes of Arthroscopic Decompression of the Anterior Inferior Iliac Spine: A Systematic Review and Meta-analysis

BACKGROUND

Anterior inferior iliac spine (AIIS) impingement has been increasingly recognized as a source of extra-articular impingement and hip pain. However, no aggregate data analysis of patient outcomes after AIIS decompression has been performed.

PURPOSE

To evaluate outcomes after arthroscopic AIIS decompression.

STUDY DESIGN

Meta-analysis; Level of evidence, 4.

METHODS

A systematic review was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. PubMed, EMBASE, and Cochrane Central Register of Controlled Trials were queried for all English-language studies reporting outcomes of arthroscopic AIIS decompression performed in isolation or in conjunction with hip impingement correction surgery. After screening, 10 articles were included. The indications for AIIS decompression were recorded, and weighted mean improvements in patient-reported outcome (PRO) scores, complication rates, and revision rates were calculated.

RESULTS

A total of 547 patients (311 women; 57%) were identified, with a total of 620 operative hips. The mean age was 28.42 ± 5.6 years, and the mean follow-up was 25.22 ± 11.1 months. A total of 529 hips (85%) underwent AIIS decompression, 530 hips (85%) underwent femoral osteochondroplasty, and 458 hips (74%) underwent labral repair. Of the patients, 13% underwent bilateral AIIS decompression. The mean modified Harris Hip Score improved from 61.3 ± 6.9 to 88.7 ± 4.7 postoperatively (change, 27.4 ± 5.7 points; P < .001), the Hip Outcome Score-Activities of Daily Living improved from 67.2 ± 10.6 to 91.1 ± 3.2 postoperatively (change, 24.0 ± 8.0 points; P = .001), and the Hip Outcome Score-Sports Specific Subscale improved from 36.8 ± 19.2 to 82.8 ± 3.8 postoperatively (change, 46.0 ± 18.2 points; P = .002). The pooled risk of postoperative complications was 1.1% (95% CI, 0.1%-2.1%), and the pooled risk of needing revision surgery was 1.0% (95% CI, 0.1%-2.0%). No complication was directly attributed to the AIIS decompression portion of the procedure.

CONCLUSION

PROs improved significantly after hip arthroscopy with AIIS decompression, with a low risk of postoperative complications and subsequent revision surgeries. Failure to identify extra-articular sources of hip pain in outcomes of femoroacetabular impingement syndrome, including from the AIIS, could lead to poorer outcomes and future revision surgery.

Subspine femoroacetabular impingement: retrospective study of a series of patients treated by hip arthroscopic resection

BACKGROUND

Femoroacetabular impingement syndrome (FAIS) is a common hip pathology that causes pain and functional limitation in young patients. subspine femoroacetabular impingement (SFAI) is an increasingly diagnosed extra-articular subtype that occurs from mechanical conflict of the anteroinferior iliac spine (AIIS) with the cervico-diaphyseal junction during hip flexion, which is poorly described in the literature.

QUESTIONS/PURPOSES

We aimed to describe the clinical, functional, and radiological results of the arthroscopic treatment of a group of patients with SFAI treated in our Hip Unit.

STUDY DESIGN

Case series.

METHODS

We present a retrospective study of ten patients with SFAI treated between 2013 and 2020 with arthroscopic resection. Clinical results were assessed with scales such as visual analog scale (VAS); modified Harris Hip Score (mHHS), and Hip disability and Osteoarthritis Outcome Score (HOOS). Radiological results were assessed with radiological measurements, magnetic resonance imaging (MRI), and computed tomography (CT) reconstructions.

RESULTS

Six patients had a Type III AIIS and four of them had Type II. Two patients had previously been surgically treated for FAIS. The range of motion improved in flexion from 107 ± 11 degrees before surgery to 127.5 ± 6 degrees (p = 0.005). MHHS improved from 48.1 (38-75.3) before surgery to 83.1 (57-91) (p = 0.007) and HOOS improved from 65.2 (58-75) to 89 (68.1-100) (p = 0.007). VAS improved from 7.3 (5-9) pre-surgical to 2.5 (0-8) post-surgical (p = 0.005). We did not have significant complications except for an asymptomatic case of heterotopic ossification (Brooker I).

CONCLUSION

Arthroscopic decompression of AIIS in SFAI patients is a safe procedure that provides satisfactory short-term functional results, improving clinical symptoms, function, sports performance, and range of motion in our study.

3D MRI of the Hip Joint: Technical Considerations, Advantages, Applications, and Current Perspectives

Magnetic resonance imaging (MRI) is a common choice among various imaging modalities for the evaluation of hip conditions. Conventional MRI with two-dimensional acquisitions requires a significant amount of time and is limited by partial-volume artifacts and suboptimal fluid-to-cartilage contrast. Recent hardware and software advances have resulted in development of novel isotropic three-dimensional (3D) single-acquisition protocols that cover the volume of the entire hip and can be reconstructed in arbitrary planes for submillimeter assessment of bony and labro-cartilaginous structures in their planes of orientation. This technique facilitates superior identification of small labral tears and other hip lesions with better correlations with arthroscopy. In this review, we discuss technical details related to 3D MRI of the hip, its advantages, and its role in commonly encountered painful conditions that can be evaluated with great precision using this technology. The entities described are femoroacetabular impingement with acetabular labral tears, acetabular dysplasia, avascular necrosis, regional tendinopathies and tendon tears, bursitis, and other conditions.

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

Purpose: Subspine impingement occurs due to a morphologically abnormal anterior inferior iliac spine (AIIS), capable of causing impingement against the distal femoral neck. The purpose of this investigation was to determine the prevalence of AIIS dysmorphism based on specimen sex, race, and age, while introducing a novel anatomic-based classification system.

Methods: A total of 1,797 adult cadaveric specimens (n = 3,594 hemipelvises) were analyzed. AIIS with the potential for subspine impingement (SSI) was recorded in each specimen by two independent authors. Specimens with AIIS dysmorphism were then reexamined to determine SSI subtype using a novel descriptive anatomic classification system.

Results: AIIS dysmorphism was present in 6.4% (n = 115 of 1,797 specimens) of specimens and 5.2% (n = 186 of 3,594) of hemipelvises. Dysmorphism was significantly more common in male specimens (p = 0.04) and African–American specimens (p = 0.04). No significant overall difference in prevalence was appreciated based on specimen age (p = 0.89). Subtype classification found that 67% of hemipelvises possessed a columnar type AIIS, 30% were bulbous and 3% hook type. Males possessed a significantly higher prevalence of columnar type AIIS dysmorphism (p < 0.001). No significant overall differences in anatomic classification were appreciated based on race (p = 0.12) or when analyzed based on age (p = 0.34).

Conclusion: AIIS dysmorphism was present in 6.4% of the 1,797 cadaveric specimens evaluated. African-American and male specimens possessed significantly higher prevalence of AIIS dysmorphism, with no significant difference based on specimen age. Columnar type AIIS dysmorphism was most common. Anatomic classification was not significantly different based on specimen race or age.

Level of Evidence: Case Series, Level IV.

Lack of Abdominal Stability and Control as a Possible Contributor to Rectus Femoris Avulsion Fracture in the Adolescent Soccer Player: A Case Report

PURPOSE

To describe evaluation and physical therapy treatment for an athlete who is male and 13 years old with healing bilateral rectus femoris avulsion fractures.

SUMMARY OF KEY POINTS

Fractures of the anterior inferior iliac spine may be linked to poor abdominal stability in soccer athletes who are male and an adolescent. The development and use of an abdominal stability screening tool could be an efficient and effective way to determine fracture risk and guide prevention programs.

CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE

Following 8 weeks of conservative physical therapy treatment, the athlete met all goals and returned to pain-free soccer activities without residual impairments. Four months following discharge, he reported full participation in soccer competition without complications. This case illustrates that abdominal weakness is a potential risk factor for anterior inferior iliac spine avulsion fracture. Screening for abdominal weakness and incorporating preventative programs into training regimens is recommended to prevent anterior inferior iliac spine injuries in this population.

Hip Impingement after Anterior Inferior Iliac Spine Avulsion Fractures: A Case Report with Review of the Literature

Avulsion fractures of the anterior inferior iliac spine (AIIS) are rare injuries in adolescent athletes. We present a case of a 15-year-old male who sustained an avulsion injury to his right AIIS when kicking a soccer ball. The patient had chronic pain and extra-articular subspinal impingement leading to decreased hip flexion and rotation. The injury occurred 1.5 years prior to symptom onset, and we were the first health care providers to manage the injury. We attempted six months of nonoperative management including activity modifications and nonsteroidal anti-inflammatory (NSAID) therapy without improvement. Although this injury can often be managed nonoperatively, his symptoms required excision of the AIIS and associated heterotopic ossification. He had an excellent outcome with return to soccer and no pain at his final follow-up visit two years after surgery. Due to the limited literature guiding the surgeon's management of AIIS avulsion injuries with associated heterotopic ossification, we provide a review of the literature detailing pre- and postoperative ranges of motion, surgical approach, fixation or excision of the avulsion fragment, and return to sport in this patient population.

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

Objective  To evaluate the clinical and radiographic results as well as complications related to patients undergoing arthroscopic treatment of subspine hip impingement.

Methods  We retrospectively evaluated 25 patients (28 hips) who underwent arthroscopic treatment of subspine impingement between January 2012 and June 2018. The mean follow-up was 29.5 months, and the patients were evaluated clinically by using the Harris hip score modified by Byrd (MHHS), the non-arthritic hip score (NAHS), and in terms of internal rotation and hip flexion. In addition, the following items were evaluated by imaging exams: the center-edge (CE) acetabular angle, the Alpha angle, the presence of a sign of the posterior wall, the degree of arthrosis, the presence of heterotopic hip ossification, and the Hetsroni classification for subspine impingement.

Results  There was an average postoperative increase of 26.9 points for the MHHS, 25.4 for the NAHS ( p  < 0.0001), 10.5° in internal rotation ( p  < 0.0024), and 7.9° for hip flexion ( p  < 0.0001). As for the radiographic evaluation, an average reduction of 3.3° in the CE angle and of 31.6° for the Alpha angle ( p  < 0.0001). Eighteen cases (64.3%) were classified as grade 0 osteoarthritis of Tönnis, and 10 (35.7%) were classified as Tönnis grade 1. Two cases (7.1%) presented grade 1 ossification of Brooker. Most hips ( n  = 15, 53.6%) were classified as type II of Hetsroni et al.

Conclusion  In the present study, patients undergoing arthroscopic treatment with subspine impingement showed improvement in clinical aspects and radiographic patterns measured postoperatively, with an average follow-up of 29.5 months.

Apophyseal avulsion fractures of the pelvis. A review

BACKGROUND AND AIM OF THE WORK

Fractures of the pelvis classically occur in adolescent during sports activities with forceful and repetitive contractions or passive lengthening acting on not yet ossified growth plates. Their misdiagnosis lead to disability, chronic pain and decrease of performances. Evidence based treatment guidelines do not exist; aim of this paper is to point out clinical outcomes, return to sport rates and complications of surgical and conservative approach.

METHODS

A systematic search based on MEDLINE database was performed in August 2017 to identify all published articles from 2010 to 2017 reporting outcomes, return to sport and complications rates after surgical and non-operative treatment of avulsion fractures of the pelvis.

RESULTS

Mean age was 14,5 years with anterior inferior iliac spine avulsion representing the most common injury (46%), followed by anterior superior iliac spine avulsion (32%), ischial tuberosity avulsion (12%) and iliac crest avulsion (11%). Rates of excellent outcome and return to sports at pre-injury levels were higher after surgical treatment; surgery has a higher risk of heterotopic ossification (9%) compared to conservative treatment (1,8%), whereas the risk of non-unions is lower (0% versus 2,5%).

CONCLUSIONS

Surgery is preferred for major dislocations and fragment sizes, providing a faster return to pre-injury level of activity, decreasing the risk of pseudoarthrosis. Conservative treatment is advisable for minimally displaced fractures when a rapid recovery is not required; patient and his family should be informed on the risk of non-unions and the eventuality of a delayed surgical approach.

Arthroscopic excision of heterotopic ossification in the rectus femoris muscle causing extra-articular anterior hip impingement

Subspine impingement is an extra-articular hip impingement syndrome that usually occurs when there is abnormal contact between an enlarged or malorientated anterior inferior iliac spine (AIIS) and the distal anterior femoral neck in straight flexion of the hip. We present the case of a 13-year-old boy with a history of left groin pain and loss of range of movement of the hip for over six months following an avulsion fracture of the AIIS during a game of rugby. He was diagnosed with subspine impingement secondary to a large lesion of heterotopic ossification in the rectus femoris; this was dissected and extracted from the muscle in toto arthroscopically. This case highlights the importance of heterotopic ossification after injury as an important cause for subspine impingement in the young adult hip. This is the first report and describes subspine impingement secondary to a large lesion of heterotopic ossification.

Secondary Ossification Center Appearance and Closure in the Pelvis and Proximal Femur

INTRODUCTION

Variable ossification patterns of the pelvis in skeletally immature patients can make the interpretation of pelvic radiographs challenging. Inconsistencies among prior studies and lack of sex comparisons underscore the need for a more comprehensive characterization of the secondary ossification centers. This study evaluates the chronology and sex differences for appearance and closure of pelvic and proximal femoral secondary ossification centers using computed tomography (CT).

METHODS

Patients who underwent abdominal and pelvic CT scans between January 2009 and December 2014 at 2 tertiary level 1 trauma centers were retrospectively reviewed. Patients between the ages of 2 and 32 years with adequate imaging of the pelvis and proximal femurs were included. Patients with a history of orthopaedic trauma or pathology affecting ossification were excluded. CT scans were assessed for the appearance and closure of the following secondary ossification centers: anterior inferior iliac spine (AIIS), anterior superior iliac spine (ASIS), femoral head (FH), greater trochanter (GT), iliac crest (IC), ischial tuberosity (IT), lesser trochanter (LT), posterior superior iliac spine (PSIS), symphysis pubis (SP), and triradiate cartilage (TRC). Basic descriptive statistics are reported.

RESULTS

A total of 496 CT scans met inclusion criteria (240 males and 256 females). The order of appearance of the secondary ossification centers was: (male) GT, LT, AIIS, IT, ASIS, PSIS, IC, and SP; (female) GT, LT, IT, AIIS, PSIS, IC, ASIS, and SP. The order of closure was similar: (male) TRC, LT, FH, AIIS, GT, ASIS, PSIS, IT, IC, and SP; (female) LT, TRC, AIIS, FH, GT, ASIS, PSIS, IT, IC, and SP. Female ossification centers appeared ∼1 to 2 years before males in all locations. Female ossification centers closed ∼1 to 2 years before males in all locations except TRC, IC, and SP.

CONCLUSIONS

The appearance and closure of the pelvis and proximal femur secondary ossification centers follow a predictable pattern of development, occurring slightly earlier in females than males. Knowledge of more precise ages of development and sex differences better characterize this complex skeletal development. Future studies may use secondary ossification centers to further evaluate skeletal maturity, assess pediatric pathology, and aid surgical management.

LEVEL OF EVIDENCE

Level III.

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

BACKGROUND

Subspine impingement is a recognized source of extraarticular hip impingement. Although CT-based classification systems have been described, to our knowledge, no study has evaluated the morphology of the anteroinferior iliac spine (AIIS) with plain radiographs nor to our knowledge has any study compared its appearance between plain radiographs and CT scan and correlated AIIS morphology with physical findings. Previous work has suggested a correlation of AIIS morphology and hip ROM but this has not been clinically validated. Furthermore, if plain radiographs can be found to adequately screen for AIIS morphology, CT could be selectively used, limiting radiation exposure.

QUESTIONS/PURPOSES

The purposes of this study were (1) to determine the prevalence of AIIS subtypes in a cohort of patients with symptomatic femoroacetabular impingement; (2) to compare AP pelvis and false profile radiographs with three-dimensional (3-D) CT classification; and (3) to correlate the preoperative hip physical examination with AIIS subtypes.

METHODS

A retrospective study of patients undergoing primary hip arthroscopy for femoroacetabular impingement syndrome was performed. Between February 2013 and November 2016, 601 patients underwent hip arthroscopy. To be included here, each patient had to have undergone a primary hip arthroscopy for the diagnosis of femoroacetabular impingement syndrome. Each patient needed to have an interpretable set of plain radiographs consisting of weightbearing AP pelvis and false profile radiographs as well as full documentation of physical findings in the medical record. Patients who additionally had a CT scan with 3-D reconstructions were included as well. During the period in question, it was the preference of the treating surgeon whether a preoperative CT scan was obtained. A total of 145 of 601 (24%) patients were included in the analysis; of this cohort, 54% (78 of 145) had a CT scan and 63% (92 of 145) were women with a mean age of 31 ± 10 years. The AIIS was classified first on patients in whom the 3-D CT scan was available based on a previously published 3-D CT classification. The AIIS was then classified by two orthopaedic surgeons (TGM, MRK) on AP and false profile radiographs based on the position of its inferior margin to a line at the lateral aspect of the acetabular sourcil normal to vertical. Type I was above, Type II at the level, and Type III below this line. There was fair interrater agreement for AP pelvis (κ = 0.382; 95% confidence interval [CI], 0.239-0.525), false profile (κ = 0.372; 95% CI, 0.229-0.515), and 3-D CT (κ = 0.325; 95% CI, 0.156-0.494). There was moderate to almost perfect intraobserver repeatability for AP pelvis (κ = 0.516; 95% CI, 0.284-0.748), false profile (κ = 0.915; 95% CI, 0.766-1.000), and 3-D CT (κ = 0.915; 95% CI, 0.766-1.000). The plane radiographs were then compared with the 3-D CT scan classification and accuracy, defined as the proportion of correct classification out of total classifications. Preoperative hip flexion, internal rotation, external rotation, flexion adduction, internal rotation, subspine, and Stinchfield physical examination tests were compared with classification of the AIIS on 3-D CT. Finally, preoperative hip flexion, internal rotation, and external rotation were compared with preoperative lateral center-edge angle and alpha angle.

RESULTS

The prevalence of AIIS was 56% (44 of 78) Type I, 39% (30 of 78) Type II, and 5% (four of 78) Type III determined from the 3-D CT classification. For the plain radiographic classification, the distribution of AIIS morphology was 64% (93 of 145) Type I, 32% (46 of 145) Type II, and 4% (six of 145) Type III on AP pelvis and 49% (71 of 145) Type I, 48% (70 of 145) Type II, and 3% (four of 145) Type III on false profile radiographs. False profile radiographs were more accurate than AP pelvis radiographs for classification when compared against the gold standard of 3-D CT at 98% (95% CI, 96-100) versus 80% (95% CI, 75-85). The false profile radiograph had better sensitivity for Type II (97% versus 47%, p < 0.001) and specificity for Types I and II AIIS (97% versus 53%, p < 0.001; 98% versus 90%, p = 0.046) morphology compared with AP pelvis radiographs. There was no correlation between AIIS type as determined by 3-D CT scan and hip flexion (rs = -0.115, p = 0.377), internal rotation (rs = 0.070, p = 0.548), flexion adduction internal rotation (U = 72.00, p = 0.270), Stinchfield (U = 290.50, p = 0.755), or subspine tests (U = 319.00, p = 0.519). External rotation was weakly correlated (rs = 0.253, p = 0.028) with AIIS subtype. Alpha angle was negatively correlated with hip flexion (r = -0.387, p = 0.002) and external rotation (r = -0.238, p = 0.043) and not correlated with internal rotation (r = -0.068, p = 0.568).

CONCLUSIONS

The findings in this study suggest the false profile radiograph is superior to an AP radiograph of the pelvis in evaluating AIIS morphology. Neither preoperative hip internal rotation nor impingement tests correlate with AIIS type as previously suggested questioning the utility of the AIIS classification system in identifying pathologic AIIS anatomy.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Sonographic Overview of Usual and Unusual Disorders of the Rectus Femoris Tendon Origins

Rectus femoris muscle proximal injuries are not rare conditions. The proximal rectus femoris tendinous anatomy is complex and may be affected by traumatic, microtraumatic, or nontraumatic disorders. A good knowledge of the proximal rectus femoris anatomy allows a better understanding of injury and disorder patterns. A new sonographic lateral approach was recently described to assess the indirect head of the proximal rectus femoris, hence allowing for a complete sonographic assessment of the proximal rectus femoris tendons. This article will review sonographic features of direct, indirect, and conjoined rectus femoris tendon disorders.

Hip Arthroscopy: Common Problems and Solutions

The use of hip arthroscopy continues to expand. Understanding potential pitfalls and complications associated with hip arthroscopy is paramount to optimizing clinical outcomes and minimizing unfavorable results. Potential pitfalls and complications are associated with preoperative factors such as patient selection, intraoperative factors such as iatrogenic damage, traction-related complications, inadequate correction of deformity, and nerve injury, or postoperative factors such as poor rehabilitation. This article outlines common factors that contribute to less-than-favorable outcomes.

Impingement around the hip: beyond cam and pincer

In this review, we bring to the attention of the reader three relatively unknown types of hip impingement. We explain the concept of low anterior inferior iliac spine (AIIS) impingement, also known as sub-spine impingement, ischio-femoral impingement (IFI) and pelvi-trochanteric impingement. For each type of impingement, we performed a search of relevant literature.We searched the PubMed, Medline (Ovid) and Embase databases from 1960 to March 2016. For each different type of impingement, a different search strategy was conducted.In total, 19 studies were included and described. No data analysis was performed since there was not much comparable data between studies.An overview of symptoms, clinical tests and possible surgical treatment options for the three different types of extra-articular impingement is provided.Several disorders around the hip can cause similar complaints. Therefore, we plead for a standardized classification. In young and athletic patients, in particular, there is much to gain if hip impingement is diagnosed early. Cite this article: EFORT Open Rev 2018;3:30-38. DOI: 10.1302/2058-5241.3.160068.

[Arthroscopic decompression of extra-articular subspinal hip impingement]

OBJECTIVE

Complete arthroscopic decompression of the impinging subspinal soft tissues and resection of the hypertrophic bone formation between the anterior hip capsule and the anterior inferior iliac spine (AIIS) or decompression of a hypertrophic AIIS.

INDICATIONS

Painful anterior hip impingement and decreased hip flexion following a hypertrophic osseous subspinal deformation.

CONTRAINDICATIONS

No clinical symptoms or decreased anterior hip function despite radiological osseous subspinal hip impingement.

SURGICAL TECHNIQUE

Hip arthroscopy in supine position on an extension table. Treatment of possible intraarticular hip pathologies in the central or peripheral compartment. Arthroscopic visualization of the hypertrophic impinging soft tissues below the AIIS and decompression using a shaver or radiofrequency device. Complete arthroscopic resection of the hypertrophic AIIS parts and the osseous subspinal deformation using a high speed burr under fluoroscopic control.

POSTOPERATIVE MANAGEMENT

Early functional rehabilitation with full weight-bearing and unlimited hip motion; 3 weeks ossification prophylaxis and 8 weeks of limitation for jumping and running sports activities.

RESULTS

There are no comparative studies or medium- and long-term study results in the literature for arthroscopic AIIS decompression. However, currently published case series show an improvement of the determined scores.

Operative Fixation of an Anterior Inferior Iliac Spine Apophyseal Avulsion Fracture Nonunion in an Adolescent Soccer Player: A Case Report

CASE

A 14-year-old male competitive soccer player presented with a history of recurrent right hip pain for 18 months. He was diagnosed with an anterior inferior iliac spine (AIIS) apophyseal avulsion fracture nonunion with subspinal impingement, which was confirmed by radiographs, computed tomography, and magnetic resonance imaging. The patient underwent surgical fixation and subspinal decompression. He returned to competitive soccer 5 months postoperatively.

CONCLUSION

AIIS apophyseal avulsion fractures occur in adolescent athletes and generally respond to nonoperative treatment. When such management is unsuccessful, surgical fixation can lead to resolution of pain with return of full function.

Anterior Inferior Iliac Spine Deformity as a Cause for Extra-articular Hip Impingement in Young Athletes After an Avulsion Fracture: A Case Report

Extra-articular hip impingement from prior traumatic injury to the anterior inferior iliac spine (AIIS) is an uncommon cause of groin pain in young athletes. Currently, the most common treatment for this injury is arthroscopic decompression. However, hip arthroscopy is not universally available and requires advanced skills. We report 2 cases of the development of extra-articular hip impingement from unusual bony exostoses off the AIIS after traumatic injury in 2 young athletes who underwent open surgical resection. The multidisciplinary sports medicine team should be aware of the development of extra-articular impingement from traumatic injury to the AIIS and that open surgical resection is a viable alternative to arthroscopic decompression.

Outcomes for Arthroscopic Treatment of Anterior Inferior Iliac Spine (Subspine) Hip Impingement

BACKGROUND

Femoroacetabular hip impingement (FAI) is now well recognized; however, anterior inferior iliac spine (AIIS; or subspine) impingement is a form of hip impingement that is underrecognized and can be an important source of hip disability and functional limitation.

PURPOSE

To investigate the outcomes after arthroscopic treatment of AIIS/subspine-related hip impingement in the absence of FAI surgery.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A prospective institutional hip preservation registry was reviewed to identify patients who underwent arthroscopic AIIS decompression without concurrent treatment of FAI. Primary outcome tools captured in the registry included the modified Harris Hip Score (mHHS), the Hip Outcome Score (HOS), and the International Hip Outcome Tool-33 (iHOT-33). Patients with minimum 1-year follow-up were included. Meaningful outcome improvement was determined per minimal clinically important difference (MCID). Statistical analyses were primarily descriptive.

RESULTS

Thirty-three patients with a mean follow-up of 19.1 months (range, 12-44 months) were identified. All patients were female, with a mean ± SD age of 26.1 ± 10.3 years. All patients were found to have an associated labral tear, and the mean acetabular version was increased at 2 and 3 o'clock (14.5° and 19.8°, respectively). Mean preoperative outcome scores on the mHHS, HOS ADL (activities of daily living), HOS sport, and iHOT-33 were 57.2 ± 15.3, 66.9 ± 18.8, 43.9 ± 23.6, and 33.5 ± 18.3, respectively. At final available follow-up, mean scores on these outcome measures were 79.5 ± 19.0, 86.8 ± 15.8, 70.4 ± 32.8, and 65.0 ± 31.0, respectively. By the 1-year follow-up, MCID had been achieved in the majority of patients across all 4 tools.

CONCLUSION

There is a paucity of outcomes evidence on AIIS/subspine-related hip impingement. This study demonstrates that isolated subspine impingement can be a cause of hip disability, even in the absence of FAI. Patients with isolated subspine impingement are more likely to be women and to present with low patient-reported outcome scores. However, meaningful outcome improvement can be achieved with arthroscopic AIIS decompression.

Imaging of impingement syndromes around the hip joint

Impingement syndromes are increasingly recognised as significant causes of hip pain and dysfunction. A broad spectrum of intraarticular and extraarticular conditions has been implicated in their pathophysiology. Physical examination is often inconclusive as clinical findings may be unclear or misleading, often simulating other disorders. With current improvements in imaging techniques and better understanding of hip impingement related pathomechanisms, these entities can be accurately diagnosed. In addition, preoperative imaging has allowed for targeted treatment planning. This article provides an overview of the various types of hip impingement, including femoroacetabular impingement, ischiofemoral impingement, snapping hip syndrome, greater trochanteric-pelvic and subspine impingement. Current literature data regarding their pathogenesis, clinical manifestation and imaging work-up are discussed.

Arthroscopic Treatment of a Displaced Nonunion of the Anterior Inferior Iliac Spine Causing Extra-articular Impingement

This report describes a case of nonunion of an anterior inferior iliac spine (AIIS) apophyseal avulsion fracture with resultant subspine impingement combined with symptomatic femoroacetabular impingement (FAI). A 16-year-old male soccer player presented with a 6-month history of right groin pain exacerbated by kicking and running. The patient was diagnosed with a displaced nonunion of the AIIS apophysis avulsion fracture causing secondary extra-articular impingement beyond cam-type FAI by physical examination and radiological findings. The authors performed arthroscopic AIIS decompression, with concurrent FAI correction and labral repair and capsular closure. At 4 months after surgery, a radiograph and a computed tomography scan showed complete bony union of the AIIS apophyseal nonunion. Modified Harris Hip Sore and Nonarthritic Hip Score improved from 74.8 and 61, respectively, to 100 for both at final follow-up. The effectiveness of arthroscopic decompression of the AIIS as part of a comprehensive minimally invasive surgery including FAI correction and labral repair resulted in complete union of the AIIS and pain-free return to sport and bony union. [Orthopedics. 2017; 40(4):e725-e728.].

No difference in prevalence of radiographic subspinal impingement of the hip between symptomatic and asymptomatic subjects

PURPOSE

The study determined the prevalence of subspinal impingement (SSI) in symptomatic and asymptomatic individuals, morphologic characteristics in symptomatic patients, and risk factors for SSI.

METHODS

The study cohort consisted of 427 patients (427 hips; median age 33.4 years; range 19-50 years) with mechanical symptoms who underwent multi-detector computed tomography arthrography (symptomatic patients) and 259 control (asymptomatic) patients who underwent abdominopelvic three-dimensional CT because of a ureter stone or minor trauma. Two orthopaedic surgeons reviewed the images to evaluate the prevalence of SSI and the relationship with morphologic abnormalities. Radiologic parameters were further compared between the SSI and non-SSI groups in symptomatic patients using the Chi-squared test or two-sample t test. Variables with p values <0.10 (sex and age) were included in the multi-variate analysis. Logistic regression analysis was carried out to identify independent risk factors for SSI.

RESULTS

The prevalence of SSI in symptomatic and asymptomatic patients was 65/427 (15.2%) and 40/259 (15.4%), respectively (n.s.). Structural bony abnormalities in symptomatic patients were not associated with the presence of SSI (n.s.). Binary logistic regression analysis revealed that youth (odds ratio 0.952, 95% CI 0.922-0.984) was the only significant factor for SSI.

CONCLUSIONS

SSI had a similar prevalence in symptomatic and asymptomatic patients and was not rare in either group. Therefore, clinical implication of SSI in symptomatic patient should be re-evaluated through further study.

LEVEL OF EVIDENCE

Level IV.

Current concepts in the diagnosis and management of extra-articular hip impingement syndromes

PURPOSE

Extra-articular hip impingement syndromes encompass a group of conditions that have previously been an unrecognised source of pain in the hip and on occasion been associated with intra-articular hip impingement as well. As arthroscopic techniques for the hip continue to evolve, the importance of these conditions has been recognised recently and now form an important part of the differential of an individual presenting with hip pain. The aim of this article, therefore, is to provide the reader with an evidence-based and comprehensive update of these syndromes.

METHODS

By reviewing past literature, the anatomy, pathophysiology, clinical features and the management of the five common extra-articular hip impingement syndromes were described.

RESULTS

The common extra-articular impingement syndromes are: 1) Ischiofemoral impingement: quadratus femoris muscle becomes compressed between the lesser trochanter and the ischial tuberosity. 2) Subspine impingement: mechanical conflict occurs between an enlarged or malorientated anterior inferior iliac spine and the distal anterior femoral neck. 3) Iliopsoas impingement: mechanical conflict occurs between the iliopsoas muscle and the labrum, resulting in distinct anterior labral pathology. 4) Deep gluteal syndrome: pain occurs in the buttock due to the entrapment of the sciatic nerve in the deep gluteal space. 5) Pectineofoveal impingement: pain occurs when the medial synovial fold impinges against overlying soft tissue, primarily the zona orbicularis. Knowledge for these syndromes still remains limited for reasons mostly relating to their low prevalence and their co-existence with typical femoro-acetabular impingement.

CONCLUSIONS

The knowledge of extra-articular hip impingement syndromes is essential and should form a part of the differential diagnoses alongside intra-articular pathology including femoro-acetabular impingement particularly in the younger patient with a non-arthritic hip.

Morphological Distribution of the Anterior Inferior Iliac Spine in Patients With and Without Hip Impingement: Reliability, Validity, and Relationship to the Intraoperative Assessment

BACKGROUND

Subspinous impingement of the anterior inferior iliac spine (AIIS) on the femoral head-neck junction is increasingly recognized as a source of hip impingement. A classification system of AIIS morphology has previously been proposed that correlates with reduced hip motion and may predispose patients to subspinous hip impingement.

PURPOSE

To examine the morphological distribution of AIIS types in patients with and without diagnosed hip impingement and correlate AIIS morphology to intraoperative findings at the time of surgery.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Three-dimensional reconstructed pelvic computed tomography scans were generated for a stratified sample of 449 hips in patients without a history of hip pain or hip impingement and 59 hips in patients with a diagnosis of hip impingement. Three blinded assessors classified the AIIS for each hip twice. The morphological distribution between symptomatic and asymptomatic patients was compared, controlling for age, sex, and affected side. Within the symptomatic cohort, AIIS morphology was compared with the intraoperative assessment of a low-lying AIIS using the Fisher exact test.

RESULTS

The intraobserver reliability of the classification system in our cohort was substantial (κ = 0.68-0.77). The interobserver reliability was moderate (κ = 0.50). The morphological distribution between symptomatic and asymptomatic patients was similar, with 75% of patients in the asymptomatic group and 80% of the patients in the symptomatic group having a type 2 or type 3 AIIS. When matched for age, sex, and affected side, there was no significant difference in the assessed classification type between the groups ( P = .55). Within the symptomatic group, there was no significant correlation between the surgeon assessment of a low-lying AIIS and a type 2 or type 3 radiographic classification ( P = .10). The positive predictive value of a type 2 or type 3 AIIS classification for hip impingement symptoms was 10%, and the negative predictive value was 91%.

CONCLUSION

These findings suggest that a high percentage of patients with AIIS morphology associated with subspinous impingement are, in fact, asymptomatic. The current radiographic classification scheme should not be used exclusively for clinical decision making.

Anterior Inferior Iliac Spine (AIIS) and Subspine Hip Impingement

BACKGROUND

Abnormal morphology of the anterior inferior iliac spine (AIIS) and the subspine region of the acetabular rim are increasingly being recognised as a source of symptomatic extra-articular hip impingement. This review article aims to highlight important differences in the pathogenesis, clinical presentation and management of extra-articular hip impingement from both the AIIS and subspine bony regions, and the outcome following surgical intervention.

METHODS

A literature review was undertaken to examine the supporting evidence for AIIS and subspine hip impingement. A narrative account of the Author's professional experience in this area, including operative technique for arthroscopic correction, is also presented.

RESULTS

Abnormal morphology of the AIIS and subspine region has been classified using cadaveric, radiological and arthroscopic means; the clinical presentation and operative treatment has been documented in several case series studies. Dual pathology is often present - recognition and treatment of both intra- and extra-articular components are necessary for good postoperative outcome.

CONCLUSIONS

AIIS and sub-spine hip impingement should be considered as distinct pathological entities, which may also co-exist. Symptom relief can be expected following arthroscopic deformity correction with the treatment of concomitant intra-articular pathology. Failure to recognise and treat the extra-articular component may affect postoperative outcome.

LEVEL OF EVIDENCE

V.

Complications in Hip Arthroscopy

BACKGROUND

Recent developments in hip arthroscopic techniques and technology have made it possible in many cases to avoid open surgical dislocation for treating a variety of pathology in the hip. Although early reports suggest favourable results' using hip arthroscopy and it has been shown to be a relatively safe procedure, complications do exist and can sometimes lead to significant morbidity.

METHODS

This is a review article. The aim of this manuscript is to present the most frequent and/or serious complications that could occur at or following hip arthroscopy and some guidelines to avoid these complications.

CONCLUSION

Most complications of hip arthroscopy are minor or transient but serious complications can occur as well. A lot of complication e.g. acetabular labral puncture go unreported. Appropriate education and training, precise and meticulous surgical technique with correct instrumentation, the right indication in the right patient and adherence to advice from mentors and experienced colleagues are all essential factors for a successful outcome. Level of evidence: V.

Arthroscopic Decompression of a Type III Subspine Impingement

Extra-articular hip impingement refers to a variety of hip disorders causing pain and limited function in young, non-arthritic patients. Recently, there has been an increased focus on analyzing the degree of anterior inferior iliac spine (AIIS) dysmorphism and its correlation with subspine impingement (SSI), defined as abutment between a prominent distal aspect of the AIIS and the anterior aspect of the femoral head-neck junction. Arthroscopic decompression of the AIIS is recognized as an effective treatment for SSI. However, there may be some inherent risks of performing this procedure arthroscopically that require further investigation.

Femoroacetabular impingement in children and adolescents

PURPOSE OF REVIEW

The present review discusses the etiology, clinical presentation, and management of femoroacetabular impingement (FAI) in the pediatric population, including etiologic and diagnostic controversies, management options, and outcomes.

RECENT FINDINGS

New evidence demonstrates conflicting results regarding how and when primary FAI develops in relation to skeletal maturity. Recent studies also discuss the effects of sex, race, and sports on FAI development and radiographic considerations in the pediatric population. Recent literature demonstrates good to excellent outcomes in the operative management of FAI in children and adolescents.

SUMMARY

FAI is a source of pediatric hip pain and can occur primarily or secondarily. It is characterized by anterior hip pain, made worse with flexion activities, decreased hip internal rotation, and a positive impingement sign. Pathologic values for radiographic measures of FAI are not clearly defined in the pediatric population. As FAI is a risk factor for osteoarthritis, early intervention in specific patients may be indicated. Hip arthroscopy, surgical hip dislocation, or combined mini-open and arthroscopic approaches are utilized, with good to excellent short, and mid-term functional results. Further study is required in the pediatric population to identify potential preventive strategies, to delineate the pathologic radiographic values of FAI, to define specific indications for operative management, and to examine long-term outcomes to determine optimal management.

A Long-term Retrospective Evaluation of Functional and Radiographic Outcomes of Pediatric Hip Surgery in Hurler Syndrome

BACKGROUND

After successful hematopoietic stem cell transplantation, maintaining function and mobility have become key goals in the management of patients with Hurler syndrome, (mucopolysaccharoidosis type 1H). The aim of this study was to establish the functional and radiologic outcomes after hip surgery in patients with this condition who had reached skeletal maturity.

METHODS

We prospectively followed 13 mucopolysaccharoidosis type 1H patients with closed triradiate cartilages who had undergone hip surgery in a single institution (Our Lady's Children's Hospital, Crumlin) in early childhood, after successful hematopoietic stem cell transplantation. Functional assessment was performed using the Harris Hip Score. Acetabular and femoral head morphology were defined using a pelvic radiograph.

RESULTS

The average age at follow-up was 18.6 years (range, 13.2 to 23.8 y). The average length of follow-up from surgical intervention was 14.6 years (range, 10.3 to 21.6 y). The average Harris Hip Score at follow-up was 61.0 (range, 19 to 91). At follow-up, 4 patients were either wheelchair bound or required a walking frame to mobilize in the community. At follow-up, all hips were in-joint with an average center edge angle of 37.7 degrees (range, 0 to 63 degrees). All hips displayed characteristic medial flattening of the femoral head. Ten hips (of 26 hips) showed radiologic degenerative changes with loss of joint space <2 mm.

CONCLUSIONS

Despite the surgical provision of stable well-covered hips, active intervention did not prevent the development of radiologic deterioration and clinically significant hip arthritis. We recommend that pediatric hip surgery in Hurler syndrome be designed with the possibility of early hip replacement in mind.

LEVEL OF EVIDENCE

Level III.

Avulsion of the direct head of rectus femoris following arthroscopic subspine impingement resection: a case report

Arthroscopic resection of the anterior inferior iliac spine (AIIS) for subspine impingement has become a relatively common procedure. The AIIS is the origin of the direct head of rectus femoris (dhRF). Previous studies have reported that removal of the contributing portion of the AIIS causing impingement is unlikely to weaken the attachment of the dhRF. The purpose of this article is to report a case of avulsion of the dhRF, following revision hip arthroscopy for the treatment of subspine impingement. A 23-year-old professional footballer underwent revision left hip arthroscopy for the treatment of subspine impingement. 5-mm of bone was resected inferior to the AIIS. Two-weeks post-operatively, he presented with sudden onset, severe left anterior thigh pain following a fall and hyperextension of his left hip. The patient felt a pop over the anterior aspect of his hip. He noticed immediate swelling, severe pain and stiffness. Examination revealed diffuse swelling, 4/5-power on straight-leg-raise, focal tenderness over the AIIS but no palpable gap. MRI confirmed the clinical suspicion of a dhRF avulsion. Given the minimal loss of power and the lack of significant retraction, the patient was treated conservatively. He was instructed to avoid excessive hip extension. He returned to full participation at 3-months. This article highlights a case of avulsion of the dhRF due to a hyperextension injury of the hip following arthroscopic resection of subspinal impingement, a previously unreported complication. Resection of soft and bone from the AIIS may weaken the insertion of the dhRF. Care should be taken during post-operative rehabilitation to avoid trauma and excessive forces on the dhRF tendon, which may lead to rupture. Rehabilitation should be focused on range of motion of the hip.

Hip impingement: beyond femoroacetabular

In the last 20 years, femoroacetabular impingement has been at the forefront of clinical practice as a cause of hip pain in young adults. As arthroscopic techniques for the hip continue to evolve, the possible presence of a new group of conditions creating mechanical conflict in and around the hip joint (ischiofemoral, subspine and iliopsoas impingement) has recently been elucidated whilst interest in already known 'impingement' syndromes (pelvic-trochanteric and pectineofoveal impingement) is now revived. This article attempts to increase awareness of these relatively uncommon clinical entities by describing their pathomorphology, contact mechanics, treatment and published results available to present. It is hoped that such knowledge will diversify therapeutic options for the clinician, thereby improving outcomes in a small but not negligible portion of patients with previously unexplained persistent symptoms.

Pelvic Apophyseal Avulsion Fractures: A Retrospective Review of 228 Cases

BACKGROUND

The aim of this study was to assess the patient demographics, epidemiology, mechanism of injury, and natural history of pelvic apophyseal avulsion fractures.

METHODS

A retrospective records review of imaging and clinical documentation was performed for patients diagnosed with pelvic apophyseal avulsion fractures at our institution from 2007 to 2013. Patient's Risser score, triradiate status, fracture location, size, and displacement were recorded based on initial injury radiographs. Further clinical and radiographic chart review was utilized to determine mechanism of injury, presence of multiple/bilateral injuries, nonunion, chronic pain, as well as any surgical interventions performed.

RESULTS

We identified 225 patients diagnosed with 228 apophyseal avulsion fractures with mean age of 14.4 years. Males represented 76% of the patients. Anterior inferior iliac spine (AIIS) avulsions were the most common, representing 49% of all avulsion fractures, followed by anterior superior iliac spine (30%), ischial tuberosity (11%), and iliac crest (10%). The most common mechanism of injury was sprinting/running (39%) followed by kicking (29%), but the mechanism varied by fracture type with 50% of AIIS avulsions caused by kicking. Multiple pelvic fractures were identified in 6% of patients. Pain >3 months out from initial injury was present in 14% of all patients and AIIS avulsion fractures were 4.47 times more likely to have chronic pain. Five nonunions were identified, 4 of which were ischial tuberosity avulsions. Initial fracture displacement >20 mm increased the risk of nonunion by 26 times. Surgical treatment was indicated in 3% of cases.

CONCLUSIONS

In this series, nearly all pelvic avulsion fractures (97%) were managed successfully with a conservative approach. Contrary to prior studies, AIIS avulsions represented half of the avulsion fractures. AIIS and ischial tuberosity fractures are at increased risk of developing future pain and nonunions, respectively. Patients and families need to be counseled about this possibility because future intervention may be necessary.

LEVEL OF EVIDENCE

Level IV-therapeutic.

A Computed Tomography Study of Gender Differences in Acetabular Version and Morphology: Implications for Femoroacetabular Impingement

PURPOSE

To assess the prevalence of acetabular retroversion in a large population of patients with asymptomatic hips. Furthermore, we sought to identify gender differences in acetabular morphology to address the current thinking that retroversion and pincer-type femoroacetabular impingement (FAI) are more common in women.

METHODS

We retrospectively reviewed morphologic features of acetabula from a consecutive series of trauma-protocol computed tomography scans of patients without pelvis injury. An automated algorithm determined the acetabular rim profile and center of the femoral head, normalized the frontal plane of the pelvis, and calculated version and coverage. We then compared male and female rim profiles, specifically focusing on version and acetabular wall coverage in the 1-o'clock (anterosuperior), 2-o'clock (central), and 3-o'clock (inferior) positions.

RESULTS

Of 1,088 patients in the database, 878 had complete data (i.e., age, ethnicity, and body mass index) and were therefore included in the final analysis. Of these, 34.3% were women and 65.7% were men. Mean global acetabular version was 19.1° for men and 22.2° for women (P < .001). Mean acetabular version for men and women was 15.5° and 18.3°, respectively, in the 1-o'clock position; 21.5° and 24.0°, respectively, in the 2-o'clock position; and 20.2° and 24.3°, respectively, in the 3-o'clock position (P < .001 for all 3). True retroversion (<0°) was observed only in the 1-o'clock position. The prevalence of true acetabular retroversion in the 1-o'clock position for men and women was 4.3% and 3%, respectively (P = .36).

CONCLUSIONS

Mean global and focal acetabular anteversion was greater in women, and the prevalence of focal cephalad retroversion in the 1-o'clock position was not significantly different compared with men. Acetabular retroversion and anterior overcoverage are not more prevalent in women in the anterosuperior acetabulum, where femoroacetabular impingement most commonly occurs.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Avulsion fracture of anterior inferior iliac spine complicated by hypertrophic malunion causing femoroacetabular impingement: Case report

•

Hypertrophic malunion of anterior inferior iliac spine causing impingement.

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Failed conservative management.

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Surgical excision of hypertrophic fragment have been done to relieve the symptom.

•

First case in Qatar.

Introduction

Avulsion fractures of the anterior inferior iliac spine are uncommon and such injuries are caused by the sudden forceful contraction of the straight head of rectus femoris muscle while the hip is hyperextended and the knee is flexed.

Case presentation

This case report describes the condition of 17 year old male footballer who complained of pain in the right groin for duration of 2 years after being involved in forceful sport activity. Detailed history, clinical examination, X-rays and CT scan revealed hypertrophic malunion of avulsion fracture of anterior inferior iliac spine causing an extra-articular type of femoroacetabular impingement. The patient was surgically treated when conservative management was unsuccessful.

Discussion

This is the first case of hypertrophic malunion of avulsion fracture of anterior inferior iliac spine with femoroacetabular impingement that has been recognized in Qatar. The patient was surgically treated in order to relieve symptoms and avoid osteoarthritis.

Conclusion

Malunited avulsion fracture of anterior inferior iliac spine can cause extra-articular femoroacetabular impingement.

Extra-articular hip impingement: a systematic review examining operative treatment of psoas, subspine, ischiofemoral, and greater trochanteric/pelvic impingement

PURPOSE

Extra-articular hip impingement can be the result of psoas impingement (PI), subspine impingement (SSI), ischiofemoral impingement (IFI), and greater trochanteric/pelvic impingement (GTPI). Symptoms may be due to bony abutment or soft-tissue irritation, and often, it is a challenge to differentiate among symptoms preoperatively. Currently, the clinical picture and diagnostic criteria are still being refined for these conditions. This systematic review was conducted to examine each condition and elucidate the indications for, treatment options for, and clinical outcomes of surgical management.

METHODS

We searched online databases (Medline, Embase, and PubMed) for English-language clinical studies published from database inception through December 31, 2013, addressing the surgical treatment of PI, SSI, IFI, and GTPI. For each condition, 2 independent assessors reviewed eligible studies. Descriptive statistics are presented.

RESULTS

Overall, 9,521 studies were initially retrieved; ultimately, 14 studies were included examining 333 hips. For PI, arthroscopic surgery resulted in 88% of patients achieving good to excellent results, as well as significant improvements in the Harris Hip Score (P = .008), Hip Outcome Score-Activities of Daily Living (P = .02), and Hip Outcome Score-Sport (P = .04). For SSI, arthroscopic decompression, with no major complications, resulted in a mean 18.5° improvement in flexion range of motion, as well as improvements in pain (mean visual analog scale score of 5.9 points preoperatively and 1.2 points postoperatively) and the modified Harris Hip Score (mean of 64.97 points preoperatively and 91.3 points postoperatively). For both IFI and GTPI, open procedures anecdotally improved patient symptoms, with no formal objective outcomes data reported.

CONCLUSIONS

This review suggests that there is some evidence to support that surgical treatment, by arthroscopy for PI and SSI and by open surgery for IFI and GTPI, results in improved patient outcomes.

LEVEL OF EVIDENCE

Systematic review of Level IV and V (case report) studies.

The modified mid-anterior portal for hip arthroscopy

The modified mid-anterior portal is a utilitarian hip arthroscopy working portal that permits dual-portal comprehensive surgery for femoroacetabular impingement and related chondrolabral procedures without the need for interportal exchange. Its distal location facilitates labral reparative and reconstructive procedures while minimizing iatrogenic acetabular chondral damage. The relatively lateral location permits instrument navigation not only along the anterosuperior acetabular rim and anterolateral proximal femur typically required for acetabuloplasty and femoroplasty but even to the posterior regions of the hip in cases of global pincer femoroacetabular impingement and posterior extensions of cam morphology and the anteromedial proximal femur while avoiding direct injury to the lateral femoral cutaneous nerve.

Origin of the direct and reflected head of the rectus femoris: an anatomic study

PURPOSE

This study aimed to define the footprint of the direct and reflected heads of the rectus femoris and the relation of the anterior inferior iliac spine (AIIS) to adjacent neurovascular (lateral circumflex femoral artery and femoral nerve), bony (anterior superior iliac spine [ASIS]), and tendinous structures (iliopsoas).

METHODS

Twelve fresh-frozen cadaveric hip joints from 6 cadavers, average age of 44.5 (±9.9) years, were carefully dissected of skin and fascia to expose the muscular, capsular, and bony structures of the anterior hip and pelvis. Using digital calipers, measurements were taken of the footprint of the rectus femoris on the AIIS, superior-lateral acetabulum and hip capsule, and adjacent anatomic structures.

RESULTS

The average dimensions of the footprint of the direct head of the rectus femoris were 13.4 mm (±1.7) × 26.0 mm (±4.1), whereas the dimensions of the reflected head footprint were 47.7 mm (±4.4) × 16.8 mm (±2.2). Important anatomic structures, including the femoral nerve, psoas tendon, and lateral circumflex femoral artery, were noted in proximity to the AIIS. The neurovascular structure closest to the AIIS was the femoral nerve (20.8 ± 3.4 mm).

CONCLUSIONS

The rectus femoris direct and reflected heads originate over a broad area of the anterolateral pelvis and are in close proximity to critical neurovascular structures, and care must be taken to avoid them during hip arthroscopy.

CLINICAL RELEVANCE

A thorough knowledge of the anatomy of the proximal rectus femoris is valuable for any surgical exposure of the anterior hip joint, particularly arthroscopic subspine decompression and open femoroacetabular impingement (FAI) surgery.

Anatomic footprint of the direct head of the rectus femoris origin: cadaveric study and clinical series of hips after arthroscopic anterior inferior iliac spine/subspine decompression

PURPOSE

The purposes of this study were to define the anatomy of the anterior inferior iliac spine (AIIS) and its relation to the footprint of the rectus femoris tendon and to evaluate on the clinical outcomes after AIIS/subspine decompression.

METHODS

The rectus origin was dissected and detached in 11 male cadaveric hips with a mean age of 54.3 ± 14.3 years (range, 33 to 74 years). The proximal-distal and medial-lateral extent of the footprint and its relation to the AIIS and acetabular rim were evaluated, with the 12-o'clock position defined as directly lateral at the insertion of the indirect head of the rectus tendon and the 1- to 6-o'clock positions defined as anterior acetabular positions. To assess the safety and efficacy of subspine decompression for AIIS deformity, clinical correlation of a series of 163 AIIS decompressions (mean age, 27.8 years; age range, 14 to 52 years) performed from January 2011 to January 2012 was completed, and outcome scores, strength deficits, and ruptures were assessed by manual muscle testing and postoperative radiographs. All patients presented with symptomatic FAI with proximal femoral and/or acetabular deformity and type 2 (131 hips) or type 3 (32 hips) AIIS morphology as defined by Hetsroni et al.

RESULTS

The mean proximal-distal and medial-lateral distances for the rectus origin footprint were 2.2 ± 0.1 cm (range, 2.1 to 2.4 cm) and 1.6 ± 0.3 cm (range, 1.2 to 2.3 cm), respectively. There was a characteristic bare area at the anteromedial AIIS. On the clock face, the lateral margin (1-o'clock to 1:30 position) and medial margin (2-o'clock to 2:30 position) of the AIIS and the indirect head of the rectus (12 o'clock) were consistent for all specimens. In the clinical series, 163 AIIS decompressions were performed for symptomatic subspine impingement. The mean modified Harris Hip Score was 63.1 points (range, 21 to 90 points) preoperatively compared with 85.3 points (range, 37 to 100 points) at a mean follow-up of 11.1 ± 4.1 months (range, 6 to 24 months) (P < .01). Short Form 12 scores improved significantly from a mean of 70.4 (range, 34 to 93) preoperatively to a mean of 81.3 (range, 31 to 99) postoperatively (P < .01). The mean pain score on a visual analog scale also improved significantly from a mean of 4.9 (range, 0.1 to 8.6) preoperatively to a mean of 1.9 (range, 0 to 7.8) postoperatively (P < .01). The mean alpha angle improved from 61.5° (range, 35° to 90°) preoperatively to 49° (range, 35° to 63°) postoperatively on anteroposterior radiographs and from 71° (range, 45° to 90°) preoperatively to 44.3° (range, 37° to 60°) postoperatively on lateral radiographs. No short- or long-term hip flexion deficits or rectus femoris avulsions were noted with up to 2 years' follow-up.

CONCLUSIONS

The origin of the rectus femoris tendon is broad on the AIIS and protective against direct head detachment with subspine decompression. This broad origin and consistent bare area anteromedially on the AIIS can be readily used by surgeons to perform a safe AIIS resection in cases of symptomatic impingement. Arthroscopic subspine decompression in addition to osteoplasty for symptomatic cam- and/or pincer-type FAI deformities can reliably improve outcome scores without significant hip flexion deficits or AIIS/rectus femoris avulsions.

CLINICAL RELEVANCE

The direct head of the rectus tendon has a broad insertion on the AIIS, and an area devoid of tendon provides a "safe zone" for subspine decompression in cases of symptomatic AIIS impingement.

Hip arthroscopy for extra-articular hip disease

The increasing popularity and success of hip arthroscopy has led to the development of related techniques for treating hip pathologies external to the joint proper. These minimally invasive endoscopic procedures serve in a diagnostic role to complement clinical evaluations and offer a therapeutic alternative to traditional open techniques. The indications for extra-articular hip endoscopy continue to expand. Recent literature describes applications for treating greater trochanteric pain syndrome, internal snapping hip, deep gluteal syndrome, and subspine impingement and for diagnosing and treating extra-articular sources of hip pain in patients who have undergone hip arthroplasty.

MR imaging of the hip: pathologies and morphologies of the hip joint, what the surgeon wants to know

MR imaging of the hip is frequently used in symptomatic patients before hip preservation surgery; it is used as a decision-making tool and as a planning tool. The MRI can confirm the preliminary working diagnosis, identify other possible sources of pain, and highlight anatomic areas that are not routinely viewed during surgery. In addition, MR imaging is capable of illustrating normal and abnormal bony morphology of the femur and pelvis; and in the case that arthrography is used, diagnostic injection can be administrated concurrently. This article highlights a surgeon's perspective on the use of MR imaging in the patient with nonarthritic hip pain.

Complications of arthroscopic surgery of the hip

Over recent years hip arthroscopic surgery has evolved into one of the most rapidly expanding fields in orthopaedic surgery. Complications are largely transient and incidences between 0.5% and 6.4% have been reported. However, major complications can and do occur. This article analyses the reported complications and makes recommendations based on the literature review and personal experience on how to minimise them.

Protrusio acetabuli: contraindication or indication for hip arthroscopy? And the case for arthroscopic treatment of global pincer impingement

Protrusio acetabuli has been considered a contraindication for hip arthroscopy. We present the case of a 33-year-old man with bilateral symptomatic protrusio acetabuli-the most extreme form of global pincer femoroacetabular impingement-and cam femoroacetabular impingement. We demonstrate the feasibility of the arthroscopic correction of severe deformities and describe key surgical steps permitting central compartment access, subtotal acetabuloplasty, labral reconstruction, and femoroplasty of the right hip, followed by later subtotal acetabuloplasty, labral refixation, and femoroplasty of the left hip, with improved outcomes at 2 and 1 years, respectively, as measured by the nonarthritic hip score. Though challenging, global pincer impingement, even acetabular protrusion, may be successfully treated with dual-portal outpatient hip arthroscopy. The modified midanterior portal enables central compartment access and extended posterior "reach" in the arthroscopic treatment of major global pincer femoroacetabular impingement, potentially making this contraindication a historical one while respectfully challenging the "global" recommendation for open surgery in this setting.