The lesser trochanter as a cause of hip impingement: pathophysiology and treatment options

Stress Fracture after Arthroscopic Lesser Trochanter Resection: Diagnosis and Therapy

We report on the case of a 52-year-old female who presented with a stress fracture after undergoing an endoscopic resection of the lesser trochanter in ischiofemoral impingement, which was resistant to maximal conservative treatment. To the best of our knowledge, this complication has not been previously described. Non-weight-bearing and intravenous alendronic acid were prescribed for management. No additional surgery was required. The patient was pain free with the ability to perform sports on the same level as before and had no complaints.

Ischiofemoral impingement syndrome: a case report and review of literature

Introduction

The etiology of ischiofemoral impingement (IFI) syndrome, an unusual and uncommon form of hip pain, remains uncertain. Some patients demonstrate narrowing of the space between the ischial tuberosity and lesser trochanter from trauma or abnormal morphology of the quadratus femoris muscle. Combined clinical and imaging aid in the diagnosis.

Case report

A 32-year-old female presented with a 3 years history of pain over the lower aspect of the right buttock, aggravated by movements of the right hip, and partially relieved with rest and medications. The right hip showed extreme restriction of abduction and external rotation. MRI of the right hip showed reduced ischiofemoral space and quadratus femoris space when compared to the left hip. The patient underwent endoscopic resection of the right lesser trochanter, with no recurrence of pain at 2 years.

Conclusion

An unusual cause of hip pain, IFI syndrome, should be suspected when hip pain at extremes of movement is associated with signal abnormality of quadratus femoris muscle. Management is tailored to address the inciting factors that precipitated the IFI syndrome.

MRI findings of ischiofemoral impingement after total hip arthroplasty are associated with increased femoral antetorsion

BACKGROUND

Ischiofemoral impingement (IFI) is a known complication after total hip arthroplasty (THA).

PURPOSE

To assess if increased postoperative (FA) is associated with magnetic resonance imaging (MRI) findings of IFI.

MATERIAL AND METHODS

In 221 patients with THA, two independent readers measured FA, ischiofemoral space (IFS), quadratus femoris space (QFS), edema, and fatty infiltration of quadratus femoris muscle. Three sets of IFI-imaging features were defined: acute IFI (set 1): IFS ≤15 mm or QFS ≤10 mm and edema in the quadratus femoris muscle; chronic IFI (set 2): IFS ≤15 mm or QFS ≤10 mm and fatty infiltration of quadratus femoris muscle Goutallier grade ≥2; acute and chronic IFI (set 3) with both criteria applicable. For each set, FA angles were compared between positive findings of IFI and negative findings of IFI. The t-test for independent samples tested statistical significance.

RESULTS

In 7.2% (16/221) of patients, findings of IFI (IFS ≤15 mm or QFS ≤10 mm and edema, n = 1; fatty infiltration, n = 9; or both, n = 6) were observed. In women, 11.4% (14/123) exhibited findings of IFI compared to 2.0% (2/98) in men. Comparison in set 1 (n = 7): mean antetorsion of 23.9° ± 9.8° (findings of acute IFI) compared to 14.4° ± 9.7° (P = 0.01). Comparison in set 2 (n = 15): mean antetorsion of 16.2° ± 6.3° (findings of chronic IFI) compared to 14.5° ± 9.9° (P = 0.49). Comparison in set 3 (n = 6): mean antetorsion of 20.4° ± 3.8° (findings of acute and chronic IFI) compared to 14.5° ± 9.9° (P = 0.01).

CONCLUSION

After THA, high postoperative FA is associated with MRI findings of acute as well as acute and chronic IFI. Findings of IFI were commonly seen in women.

Rotation osteotomy of the distal femur influences coronal femoral alignment and the ischiofemoral space

INTRODUCTION

Despite the fact that osteotomies around the knee represent well-established treatment options for the redistribution of loads and forces within and around the knee joint, unforeseen effects of these osteotomies on the remaining planes and adjacent joints are still to be defined. It was, therefore, the aim of this study to determine the influence of a distal femoral rotation osteotomy on the coronal limb alignment and on the ischiofemoral space of the hip joint.

MATERIALS AND METHODS

Long-leg standing radiographs and CT-based torsional measurements of 27 patients undergoing supracondylar rotational osteotomies of the femur between 2012 and 2019 were obtained and utilized for the purpose of this study. Postoperative radiographs were obtained after union at the osteotomy site. The hip-knee-ankle angle (HKA), the mechanical lateral distal femur angle (mLDFA), and the ischiofemoral space were measured. Comparison between means was performed using the Wilcoxon-Mann-Whitney test.

RESULTS

Twenty-seven patients underwent isolated supracondylar external rotation osteotomy to reduce the overall antetorsion of the femur. The osteotomy resulted in a 2.4° ± 1.4° mean increase in HKA and 2.4 mm ± 1.7 mm increase in the ischiofemoral space (p < 0.001).

CONCLUSION

Supracondylar external rotation osteotomy of the femur leads to valgisation of the coronal limb alignment and increases the ischiofemoral space. This is resultant to the reorientation of the femoral antecurvature and the femoral neck. When planning a rotational osteotomy of the lower limb, this should be appreciated and may also aid in the decision regarding osteotomy site.

Conservative Treatment of Avulsion Injuries of the Lesser Trochanter in Adolescent Athletes

BACKGROUND

 Avulsion injuries of the lesser trochanter apophysis are relatively uncommon injuries and there have been no peer-reviewed case series dedicated to the evaluation and treatment of this injury. The purpose of this study is to characterize avulsion injuries of the lesser trochanter apophysis, review treatment protocols, and time to return to sport.  Methods: We reviewed 30 confirmed avulsion fractures of the lesser trochanter. Clinical data were reviewed to evaluate treatment protocols, duration, and time to return to sport. Radiographs were reviewed to confirm lesser trochanter avulsion and fracture displacement.

RESULTS

There were 26 males and 4 females, with the average age at the time of injury being 14.2 years. Treatment modalities consisted of protective weight-bearing, discontinuation of the patient's sport in all cases, and formal physical therapy in 18 cases. The average treatment duration was 30.7 days. The mean follow-up time was 102 days. The radiographic assessment demonstrated an average fracture displacement of 5.1 mm. The average return to sport was 11 weeks.

CONCLUSION

This is the first large case series studying avulsion injuries of the lesser trochanter. We have shown that these athletes can be managed non-surgically and can successfully return back to sport within three months.

Supracondylar rotation osteotomy of the femur influences the coronal alignment of the ankle

Purpose

Osteotomies represent well-established treatment-options for the redistribution of loads and forces within and around the knee-joint. Effects of these osteotomies on the remaining planes and adjacent joints are not fully understood. The aim of this study was to determine the influence of a distal-femoral-rotation-osteotomy on the coronal alignment of the ankle. It was hypothesized that supracondylar-external-rotation-osteotomy of the distal femur leads to a change in the coronal orientation of the ankle joint.

Methods

Long-leg standing radiographs and CT-based torsional measurements of 27 patients undergoing supracondylar-rotational-osteotomy of the femur between 2012 and 2019 were obtained and utilized for the purpose of this study. Postoperative radiographs were obtained after union at the osteotomy-site. The hip-knee-ankle-angle (HKA), the mechanical-lateral-distal-femur-angle (mLDFA), and Tibia-Plafond-Horizontal-Orientation-Angle (TPHA) around the ankle were measured. Comparison between means was performed using the Wilcoxon-Mann–Whitney test.

Results

Twenty-seven patients with high femoral antetorsion (31.3° ± 4.0°) underwent supracondylar-external-rotation-osteotomy. The osteotomy led to a reduced antetorsion (17.4 ± 5.1; p < 0.001) and to a valgisation of the overall limb-alignment. The HKA decreased by 2.4° ± 1.4° (p < 0.001). The TPHA decreased by 2.6° (p < 0.001).

Conclusions

Supracondylar external rotation osteotomy of the femur leads to lateralization of the weight bearing line at the knee and ankle due to valgisation of the coronal limb alignment. The mobile subtalar joint has to compensate (inversion) for the resulting valgus orientation of the ankle to ensure contact between the foot and the floor. When planning a rotational osteotomy of the lower limb, this should be appreciated – especially in patients with a preexisting valgus alignment of the lower extremities or restricted mobility in the subtalar joint.

The ischiofemoral space of the hip is influenced by the frontal knee alignment

PURPOSE

The ischiofemoral distance (IFD), defined as the distance between the ischial tuberosity and the lesser trochanter of the femur, is gaining recognition as an extra-articular cause of hip pain. It is unknown whether the IFD is influenced by the frontal knee alignment. The aim of this study was to determine the influence of realignment surgery around the knee on the IFD. It was hypothesized that valgisation osteotomy around the knee is associated with reduction of the IFD.

METHODS

A consecutive series of 154 patients undergoing frontal realignment procedures around the knee in 2017 were included in this study. Long-leg standing radiographs were obtained before surgery and postoperatively. The IFD was measured between the ischium and the lesser trochanter at three different levels (proximal, middle and distal margins of the lesser trochanter parallel to the horizontal orientation of the pelvis) on standardized long-leg radiographs with the patient in upright standing position. The knee alignment was determined by measuring the hip knee ankle angle, mechanical lateral distal femur angle and the medial mechanical proximal tibia angle. Linear regression was performed to determine the influence of the change of frontal knee alignment on the IFD.

RESULTS

Linear regression showed a direct influence of the overall change in frontal knee alignment on the IFD of the hip, regardless of the site of the osteotomy (β-0.4, confidence-interval - 0.5 to - 0.3, p < 0.001). Valgisation osteotomy around the knee induced a significant reduction of the ipsilateral IFD (p < 0.001), while varisation osteotomy induced a significant increase (p < 0.001). The amount of ISD change was 0.4 mm per corresponding degree of change in frontal knee alignment.

CONCLUSION

These findings are relevant to both the hip and knee surgeons when planning an osteotomy or arthroplasty procedure. Correction of a malalignment of the knee may resolve an ischiofemoral conflict in the hip. The concept deserves inclusion in the diagnostic workup of both the hip and knee joints.

LEVEL OF EVIDENCE

IV.

Ischiofemoral Impingement Syndrome Secondary to Arteriovenous Malformation of the Quadratus Femoris: A Case Report

CASE

Ischiofemoral impingement syndrome (IFIS), an unusual presentation of hip pain, is frequently missed in clinical practice. We report a case of a 27-year-old man with complaints of gradual onset nonprogressive right gluteal pain with hip movement restriction for the past 5 years that was not relieved with conservative measures. Right hip magnetic resonance imaging revealed a vascular abnormality of the right quadratus femoris muscle suggestive of IFIS. This abnormal muscle was surgically excised, and its histologic evaluation was remarkable for an arteriovenous malformation.

CONCLUSION

The patient's longstanding symptomatic IFIS was ultimately attributed to a rare arteriovenous malformation of the quadratus femoris that resolved with surgical excision.

Arthroscopic Reduction and Fixation of a Lesser Trochanter Avulsion Nonunion

Identifying and treating avulsion fractures of the pelvis and proximal femur in adolescent athletes has become increasingly more important as the rate of competitive sports participation has grown. The majority of these fractures can be treated conservatively, with most returning to full activity. Surgical treatment of these injuries has been traditionally indicated for >2 cm displacement, painful nonunion, symptomatic exostosis formation, or persistent pain and symptoms. Lesser trochanter avulsion injuries are extremely rare and literature outlining their surgical treatment lacking. We present our method of arthroscopic reduction and fixation of lesser trochanter avulsion nonunions.

Hip morphology predicts posterior hip impingement in a cadaveric model

INTRODUCTION

Posterior hip impingement is a recently-identified cause of hip pain. The purpose of this study is to characterise posterior femoroacetabular and ischiofemoral impingement and identify its predisposing morphologic traits.

METHODS

Two hundred and six cadaveric hips were randomly selected and taken through controlled motion in two pure axes associated with posterior hip impingement: external rotation (through the mechanical axis) and adduction (coronal plane). The range of motion and location of impingement was noted for each specimen. Morphologic traits including femoral/acetabular version, and true neck-shaft angle (TNSA) were also measured.

RESULTS

External rotation impingement occurred between the femoral neck and acetabulum in 83.0% of hips, and between the lesser trochanter and ischial tuberosity in 17.0%. Adduction impingement occurred between the lesser trochanter and ischial tuberosity in 78.6% of hips, and between the femoral neck and acetabulum in 21.4%. Multiple regression revealed that increased femoral/acetabular version predicted earlier external rotation and adduction impingement. Unstandardised betas ranging from -0.39 to -0.64 reflect that each degree of increased femoral/acetabular version individually accounts for a loss of external rotation or adduction of approximately half a degree before impingement ( p < 0.001 for each). Increased TNSA was associated with earlier adduction impingement only (unstandardised beta -0.35, p = 0.005).

DISCUSSION

Relative femoral/acetabular anteversion was associated with earlier posterior hip impingement. Coxa valga was associated with earlier adduction impingement, but protective against external rotation impingement. These findings highlight the importance of monitoring correction during femoral/acetabular osteotomies, as overcorrection of retroversion may predispose to earlier posterior impingement.

Dynamic Ischiofemoral Impingement: Case-Based Evidence of Progressive Pathophysiology from Hip Abductor Insufficiency: A Report of Two Cases

CASE

We describe 2 patients with no historical, examination, or imaging evidence of ischiofemoral impingement; they both developed hip abductor insufficiency and subsequent ischiofemoral impingement with progression that was confirmed by examination and advanced imaging.

CONCLUSION

Hip abductor insufficiency may lead to dynamic progressive ischiofemoral impingement. Hemipelvic instability from hip abductor weakness results in a Trendelenburg gait, narrowing the ischiofemoral space and impinging the quadratus femoris muscle. Treatment options for dynamic ischiofemoral impingement potentially can focus on treatment of the underlying cause of the hemipelvic instability, preventing additional ischiofemoral-space narrowing and quadratus femoris damage by minimizing the Trendelenburg gait.

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.

Endoscopic Lesser Trochanter Resection With Refixation of the Iliopsoas Tendon for Treatment of Ischiofemoral Impingement

Ischiofemoral impingement is a source of hip pain derived from impingement between the lesser trochanter and the ischium. Lesser trochanter excision has been recommended for recalcitrant ischiofemoral impingement through either an anterior or posterior approach. However, neither of these approaches involves refixation of the iliopsoas tendon. We describe an endoscopic procedure involving anterior trochanter-plasty, minimizing the risk of sciatic complications, with refixation of the partially detached iliopsoas tendinous insertion, potentially minimizing compromise to hip flexion strength and anterior hip stability.

[Surgical therapy of ischiofemoral impingement by lateralizing intertrochanteric osteotomy]

OBJECTIVE

Lateralizing, derotating intertrochanteric varus osteotomy to increase the ischiofemoral space to counter painful impingement of the lesser trochanter and the os ischium with resulting entrapment of quadratus femoris muscle.

INDICATIONS

Symptomatic ischiofemoral impingement (IFI) caused by Coxa valga et antetorta, Coxa valga or Coxa antetorta, or a short femoral neck.

CONTRAINDICATIONS

Anatomic configuration suggestive of IFI in asymptomatic patients. Symptomatic IFI caused by another underlying pathology. Valgus deformity of the knee.

SURGICAL TECHNIQUE

Measurement of femoral antetorsion. Planning of the osteotomy, lateralization, varus angle for correction, rotation and offset correction, leg length change, and osteosynthesis plate. General or spinal anesthesia in supine or lateral position. Skin incision (15 cm) beginning lateral of the greater trochanter tip, distally along the axis of the femur. Preparation onto the femur by L‑shaped dissection of the vastus lateralis from the bone. A Kirschner(K-)wire is then positioned along the anterior femoral neck to designate the femoral neck antetorsion. A triangle set on the lateral femoral cortexis is used to determine the osteotomy angle. In the thus determined angle, a second K‑wire is shot centrally along the femoral neck axis just inferior to its cranial cortex. About 5 mm distal to the second wire, the entry for the blade is prepared using a drill. Using the blade setting instrument, the blade is introduced into the femoral neck, then slightly pulled back. The rotation is then marked on the anterior femoral cortex proximal and distal to the planned osteotomy and the osteotomy is performed. A blade plate without displacement is impacted. The osteotomy is then reduced, the distal fragment pulled laterally onto the plate, and the screws inserted after compression of the osteotomy with a tension device.

POSTOPERATIVE MANAGEMENT

Touch-toe bearing for 6 weeks, then radiological assessment of osteotomy healing before an increase in weight bearing (15 kg/week). Hip flexion limited to 90° for 6 weeks. Elective implant removal after 12-18 months.

RESULTS

Studies of this lateralizing varus osteotomy have not been published. The 25-year results of the conventional derotating intertrochanteric varus osteotomy technique show good functional results and low complication rates, with non-union being the most common. Arthroscopic resection of the lesser trochanter has been reported as a surgical alternative in the treatment of IFI in case reports and small series. Advantages of the osteotomy are the restoration of biomechanics and preservation of iliopsoas tendon insertion.

Short-term outcomes of open hip preservation surgery for symptomatic extraarticular femoroacetabular impingement

INTRODUCTION

The purposes of this study were to describe: (i) short-term disease-specific patient-reported outcome scores (PROMs); and (ii) factors associated with reoperation or treatment failure in patients undergoing open hip preservation surgery for symptomatic extraarticular FAI.

METHODS

Patients undergoing open hip preservation surgery for symptomatic extraarticular FAI were identified from a prospective, single-centre hip preservation registry (n = 51 patients; median clinical follow-up 24 [range 11-49] months). Hip-specific PROMs were assessed preoperatively, 6 months, and each year subsequently. Patients undergoing reoperation or treatment failure (<10 point improvement in iHOT-33 postoperatively) over the study period were identified. Preoperative associated factors were explored on a univariate basis.

RESULTS

International Hip Outcome Tool-33 (iHOT-33) improved from 33 (standard deviation [SD] 18) to 62 (26) at most recent follow-up and 76% of patients improved by minimum clinically important difference (MCID). Harris Hip Score improved from 53 (15) to 75 (17) at most recent follow-up and 79% of patients improved by MCID. Hip Outcome Score (HOS) Sport improved from 45 (26) to 66 (28) at most recent follow-up and 60% of patients improved by MCID. Continued improvements in mean follow-up scores were seen from 1 year to 2 years. Overall, 7 patients underwent reoperation and 9 patients failed to improve by MCID. Preoperative HOS Sport was higher in patients experiencing reoperation or treatment failure (58 [SD 19] vs. 40 [SD 27] respectively; p = 0.03). No other associated demographic, physical examination, or radiographic factors were found.

CONCLUSIONS

Open treatment of extraarticular FAI results in short-term improvements in hip-specific PROMs in most patients. Higher HOS Sport scores were associated with reoperation or treatment failure. Longer-term follow-up is necessary to define maximum improvements in this challenging patient population.

Ultrasound Finding of Ischiofemoral Impingement Syndrome and Novel Treatment With Botulinum Toxin Chemodenervation: A Case Report

Ischiofemoral impingement syndrome (IFIS) is a rare and poorly understood condition that leads to deep gluteal pain, groin, and/or medial thigh pain. It has unique diagnostic challenges, with limited nonoperative treatment options. It is caused by the impingement of the quadratus femoris by the lesser trochanter and the ischium. Currently, there are no validated physical examination maneuvers for IFIS, and the value of ischiofemoral interval for establishing IFIS is also uncertain. Ultrasound-guided corticosteroid injections have been reported. Here, we present a case of novel treatment of IFIS with botulinum chemodenervation that led to long-term symptomatic and functional improvement in this patient, with the unique ultrasound findings of the "eruption sign."

LEVEL OF EVIDENCE

IV.

Extra-articular hip impingement: a review of the literature

Hip and groin pain is a common clinical problem. Multiple causes can generate hip or groin pain, often sharing clinical and demographic characteristics. Diagnostic imaging tests play an important role in the etiological diagnosis. New forms of extra-articular hip impingement have recently been recognized as a cause of hip pain and limited function especially in young active patients. These conditions include ischiofemoral impingement, anterior inferior iliac spine and subspine impingement, iliopsoas impingement and greater trochanteric-pelvic impingement. In general, they are caused by a mechanical conflict with an abnormal or excessive contact between the proximal femur and pelvis and/or soft tissue between them. In this manuscript we review the physiopathology, clinical presentation, the most common radiologic findings and treatment of these forms of extra-articular hip impingement.

How to address ischiofemoral impingement? Treatment algorithm and review of the literature

Ischiofemoral impingement (IFI) is a rare cause of hip pain defined by a narrowing of the space between the lateral aspect of the os ischium and the lesser trochanter of the femur. Several underlying anatomic, functional and iatrogenic pathologies have been identified for symptomatic IFI in native hip joints and after total hip arthroplasty. Clinical symptoms vary but most commonly consist of pain of the lower buttock and groin including the inner thigh, and a snapping or clunking phenomenon is often reported. Symptoms may be provoked by a combined extension, adduction and external rotation during physical examination and during long-stride walking. Radiographs of the pelvis and an axial or false-profile-view of the hip as well as magnetic resonance imaging (MRI)-scans should be obtained to strengthen the diagnosis. On MRI, the quadratus femoris muscle signal and the space confined by the anatomic structures surrounding the muscle, the quadratus femoris space, are to be assessed. Targeted infiltration of the muscle can be helpful both diagnostically and therapeutically. The literature on differential diagnoses and treatment options for IFI is limited; therapeutic suggestions are offered only in case reports and series. With this work, we aim to give a systematic approach to the non-surgical and surgical treatment options for IFI based upon the current literature and the authors' personal experience.

Differential proteomic screening and identification for non-traumatic necrotic femoral osseous tissue

Currently, there is a lack of effective early screening and detection methods for femoral head necrosis. Current research on most orthopedic diseases focuses on proteomics in the preliminary stage. The recent fluorescence differential in gel electrophoresis (DIGE) has advantages such as a high reproducibility, high sensitivity, high throughput, and high dynamic range. It is currently one of the most widely used quantitative proteomic research means. We conducted this study to investigate the pathogenesis of non-traumatic femoral head necrosis using the fluorescence DIGE to screen non-traumatic femoral head necrosis based on proteomics and provide a theoretical basis for screening possible biomarkers and molecular targeted treatment. The DIGE technique was used to separate the protein. An electrophoretogram was established on the basis of scanning and analysis. Identification and a bioinformatics analysis were conducted for the differential protein. The protein with differential expression of over 2-fold was excavated and ionized by means of substrate assisted laser desorption. The flight time was identified with a mass spectrometer (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, MALDI-TOF/TOF). The formation on sequences, structures and functions of these proteins were obtained through database retrieval. Western blot analysis was used to verify the differential protein expression and the reliability of the DIGE result was verified. DIGE was used to successfully separate 1,500±40 protein spots. There were 252 significant differential protein spots. The Ettan™ Spot Picker automatic work station was used to excavate 49 significant differential protein spots with expression difference over 2-fold. The MALDI-TOF/TOF mass spectrometer was used to identify these differential protein spots. Six proteins were identified in total, which include apolipoprotein A1 (APOA1), fibrous protein original chain, fibrous protein original chain, serum albumin, sulfur-oxygen protein peroxiredoxin 2 (PRDX2) and actin. APOA1 and PRDX2 were subject to western blot analysis detection; results were consistent with the DIGE result. Based on an analysis of the biological information, these proteins may be associated with the incidence and progression of femoral head necrosis.

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.

Accuracy of 2 Clinical Tests for Ischiofemoral Impingement in Patients With Posterior Hip Pain and Endoscopically Confirmed Diagnosis

PURPOSE

To establish the accuracy of the long-stride walking (LSW) and ischiofemoral impingement (IFI) tests for diagnosing IFI in patients whose primary symptom is posterior hip pain.

METHODS

Confirmed IFI cases and cases in which IFI had been ruled out were identified considering imaging, injections, and endoscopic assessment, combined with pain relief and negative IFI-specific tests after treatment. Demographic data, duration of symptoms, pain location, ischiofemoral space, quadratus femoris space, quadratus femoris edema, surgical findings, and visual analog scale score for pain before and after treatment were computed for all patients included in this study. Sensitivity, specificity, predictive values, likelihood ratios, and diagnostic odds ratios were computed individually for the LSW test and IFI test.

RESULTS

Cases from 1,166 consecutive hip operations and charts from 564 consecutive outpatients were retrospectively reviewed to identify patients who underwent injection and/or endoscopic surgery because of posterior hip pain. Thirty individuals (21 women and 9 men) with a mean age of 49.8 years (range, 20 to 76 years; standard deviation, 13.0 years) were included for analysis. Of the 30 patients, 17 (56.6%) were confirmed as positive for IFI and 13 (43.4%) were confirmed as negative for IFI. The IFI test had a sensitivity of 0.82, specificity of 0.85, positive predictive value of 0.88, negative predictive value of 0.79, positive likelihood ratio of 5.35, negative likelihood ratio of 0.21, and diagnostic odds ratio of 25.6. The LSW test had a sensitivity of 0.94, specificity of 0.85, positive predictive value of 0.89, negative predictive value of 0.92, positive likelihood ratio of 6.12, negative likelihood ratio of 0.07, and diagnostic odds ratio of 88.8.

CONCLUSIONS

In patients with complaints of posterior hip pain and negative evaluation findings for lumbosacral spine involvement or static/dynamic mechanical axis malalignment, the IFI and LSW tests are highly accurate to help identify those with or without IFI. LEVEL OF EVIDENCE: Level III, diagnostic study.

Treatment of ischiofemoral impingement: results of diagnostic injections and arthroscopic resection of the lesser trochanter

Ischiofemoral impingement (IFI) is an often unrecognized cause of hip pain caused by abnormal contact between the lesser trochanter and the ischium. To date, surgical treatment for those whose pain is not relieved by activity modification and steroid injections has not been defined. This study describes our imaging protocol and reports the results of arthroscopic, lesser trochanteric resections that were performed to treat this condition. Seven patients with symptomatic, MRI-documented IFI had ultrasound injections of ropivicaine and steroid into their ischiofemoral space. The injections provided complete but only transient relief of their groin and buttock pain and thus, all seven ultimately had an arthroscopic resection of their lesser trochanter. All hips were evaluated preoperatively and at 3, 6 and 12 months postoperatively with Byrd's modified Harris hip scoring system. Average age of the seven patients was 46 years and there were five females and one male. Preoperative scores averaged 43 points. After surgery, all patients used crutches for 4-6 weeks, and had 6-week scores that averaged 58 points. The patients and their scores continued to improve and at 6 and 12 months, their scores averaged 86 and 91 points, and none had chronic hip flexor weakness or recurrence of their hip pain or snapping. Arthroscopic iliopsoas tenotomies in combination with a resection of the lesser trochanter will provide complete relief of the painful snapping, groin and buttock pain caused by ischiofemoral impingement.

Extrarticular hip impingement

Extrarticular causes of impingement have a current, interesting role in the complaint of groin pain in athletes. Subspine impingement is related to a prominent anterior inferior iliac spine (AIIS) and is actually described as a frequent cause of groin pain. Ischiofemoral impingement is described when the space between the lesser trochanter is decreased. Psoas impingement appears between the psoas tendon and the anterior labrum and anterior acetabular rim.

Femoral Neck Anteversion and Lesser Trochanteric Retroversion in Patients With Ischiofemoral Impingement: A Case-Control Magnetic Resonance Imaging Study

PURPOSE

To assess the relationship between the femoral neck version (FNV) and lesser trochanteric version (LTV) in symptomatic patients with ischiofemoral impingement (IFI) as compared with asymptomatic hips.

METHODS

The FNV and LTV of patients with symptomatic IFI who underwent magnetic resonance imaging assessment including a standardized femoral version study protocol were compared with those of patients with asymptomatic hips in this retrospective, observational study. Patients with isolated intra-articular pathology, prior hip fracture, and lesser trochanter deformity were excluded. The FNV, LTV, ischiofemoral space, and quadratus femoris space were evaluated on axial magnetic resonance imaging, as well as the angle between the LTV and the FNV. Independent t-tests were used to determine differences between groups.

RESULTS

Data from 11 out 15 symptomatic patients and 250 out of 320 asymptomatic patients were analyzed. The mean ischiofemoral space (11.9 v 22.9 mm; P < .001; 95% confidence interval [CI], 6.9 to 15.2) and mean quadratus femoris space (7.2 mm v 14.9 mm; P < .001; 95% CI, 5.4 to 8.6) were significantly smaller in symptomatic patients versus asymptomatic patients. There was no difference in mean LTV between groups (-23.6° v -24.2°; P = .8; 95% CI, -7.5 to 6.4), however, the mean FNV (21.7° v 14.1°; P = .02; 95% CI, -14.2 to -1.1) and the angle between the FNV and LTV on average (45.4° v 38.3°; P = .01; 95% CI, -12.9 to -1.3) were higher in symptomatic than in asymptomatic patients, with statistical significance.

CONCLUSIONS

The femoral mean neck anteversion and the mean angle between the FNV and LTV are significantly higher in patients with symptomatic IFI. The mean LTV is not increased in patients with symptomatic ischiofemoral impingement as compared with those patients with asymptomatic hips.

LEVEL OF EVIDENCE

Level III, diagnostic study.

A MRI study of the lesser trochanteric version and its relationship to proximal femoral osseous anatomy

The purpose of this study is to quantify the lesser trochanteric version and determine the angle and the relationship between lesser trochanter and femoral neck version. Investigate the influence of the lesser trochanter version in the width of ischiofemoral space. Two hundred and fifty asymptomatic hips were evaluated with axial magnetic resonance image. The lesser trochanter version was calculated. The difference between the femoral neck version and the lesser trochanter version formed the angle between each structure. The width of ischiofemoral space was measured and its relationship with the lesser trochanter version was determined. The mean lesser trochanter version was -24° ± 11.5° (range, - 54° to + 17°) with a coefficient variation of 47.45%. The mean femoral neck version measured 14.0° ± 10.8° (range, -16° to 50°), with a coefficient variation of 81.32%. The lesser trochanter/femora neck angle was 38.4° ± 9.6° (range, 8° to 67°), coefficient variation of 30%, with a moderate correlation between the structures (r = 0.63, P < 0.01). The mean ischiofemoral space was 22.9.0 ± 7.0 mm (range, 10.3 to 55 mm), and a weak correlation was found between ischiofemoral space and lesser trochanteric version (r = -0.16, P < 0.05). The lesser trochanteric version showed a high variation with a moderate relationship with the femoral neck version. The lesser trochanteric version does not influence the width of the ischiofemoral space.

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.

Iliopsoas tendon insertion footprint with surgical implications in lesser trochanterplasty for treating ischiofemoral impingement: an anatomic study

The objective of this study was to describe the footprint location of the iliopsoas tendon on the lesser trochanter to clarify the surgical implications of the lesser trochanterplasty for treating ischiofemoral impingement. Ten non-matched, fresh-frozen, cadaveric hemipelvis specimens (average age, 62.4 years; range, 48–84 years; 7 male and 3 female) were included. Registered measures included bony parameters of the lesser trochanter (lesser trochanteric area, distances from the tip to the base in a coordinate system, height and area) and tendinous iliopsoas footprint descriptions (areas and detailed location). The mean height of the lesser trochanter was 13.1 (SD ± 1.8) mm, with female having a smaller lesser trochanter on average (11.3, SD ± 2.0). A double tendinous footprint was found in 7 (70%) specimens. The average area of the single- and double-footprint was 211.2 mm² and 187.9 mm², respectively. An anterior cortical area with no tendinous insertion on the anterior aspect of lesser trochanter was present in all specimens and measured 4.9 mm (SD ± 0.6) on average. The mean ratio between the bald anterior wall and the lesser trochanter height was 38% (SD ± 0.05). The iliopsoas tendon footprint is double (psoas and iliacus) in most cases and is located on the anteromedial tip of the lesser trochanter. A bald anterior wall on the bottom of the lesser trochanter indicates that a partial or total lesser trochanterplasty for increasing the ischiofemoral space without detaching partially or entirely the iliopsoas tendon is improbable.

Ischiofemoral impingement syndrome: a meta-analysis

OBJECTIVE

The aims of this article are to review the imaging characteristics of ischiofemoral impingement (IFI), summarize measurement thresholds for radiologic diagnosis based on a meta-analysis of the literature and raise awareness among radiologists and clinicians of this entity.

MATERIALS AND METHODS

A PubMed search restricted to the English language containing the keywords "ischiofemoral impingement" and "quadratus femoris MRI" was performed, and citations in these articles were also used to identify a total of 27 studies discussing ischiofemoral impingement. After excluding case reports and non-representative studies, there were five remaining articles including 193 hip MRIs of IFI in 154 subjects (133 female, 21 male) and 135 asymptomatic control hip MRIs from 74 subjects (55 female, 19 male). Additionally, we performed a retrospective database search of pelvic and hip MRI reports from our institution including the terms "quadratus femoris" or "ischiofemoral impingement" from a 9-year period and 24 hip MRIs from 21 patients (18 female, 3 male) with IFI with 5 asymptomatic contralateral control hip MRIs identified. In all, 217 hip MRIs of IFI and 140 control cases were included. A meta-analysis of these hip MRIs was conducted to determine optimal thresholds of the ischiofemoral space (IFS) and quadratus femoris space (QFS) for identifying IFI.

RESULTS

Cases of IFI showed significantly smaller IFS and QFS compared to controls (14.91 ± 4.8 versus 26.01 ± 7.98 and 9.57 ± 3.7 versus 15.97 ± 6.07, measured in mm, respectively, p < 0.0001 for both). Pooled analysis revealed that for IFS, using a cutoff of ≤ 15 mm yielded a sensitivity of 76.9%, specificity of 81.0% and overall accuracy of 78.3%. For QFS, a cutoff of ≤ 10.0 mm resulted in 78.7% sensitivity, 74.1% specificity and 77.1% overall accuracy.

CONCLUSION

IFI is a potential cause of hip pain that can be accurately diagnosed with MRI in conjunction with clinical findings. Using the proposed measurement thresholds may better identify patients with this impingement syndrome so that optimal treatment options can be pursued.

Relative femoral neck lengthening improves pain and hip function in proximal femoral deformities with a high-riding trochanter

BACKGROUND

Complex proximal femoral deformities, including an elevated greater trochanter, short femoral neck, and aspherical head-neck junction, often result in pain and impaired hip function resulting from intra-/extraarticular impingement. Relative femoral neck lengthening may address these deformities, but mid-term results of this approach have not been widely reported.

QUESTIONS/PURPOSES

Do patients who have undergone relative femoral neck lengthening show (1) less hip pain and greater function; (2) improved radiographic parameters; (3) significant complications requiring subsequent surgery; and (4) progression of osteoarthrosis (OA) or conversion to total hip arthroplasty (THA) at mid-term followup?

METHODS

We retrospectively reviewed 40 patients (41 hips) with isolated relative femoral neck lengthening between 1998 and 2006 with sequelae of Legg-Calvé-Perthes disease (38 hips [93%]), slipped capital femoral epiphysis (two hips [5%]), and postseptic arthritis (one hip [2%]). During this time, the general indications for this procedure included a high-riding greater trochanter with a short femoral neck with abductor weakness and symptomatic intra-/extraarticular impingement. Mean patient followup was 8 years (range, 5-13 years), and complete followup was available in 38 patients (39 hips [95%]). We evaluated pain and function with the impingement test, limp, abductor force, Merle d'Aubigné-Postel score, and range of motion. Radiographic parameters included trochanteric height, alpha angle, and progression of OA. Subsequent surgeries, complications, and conversion to THA were summarized.

RESULTS

The proportion of positive anterior impingement tests decreased from 93% (38 of 41 hips) preoperatively to 49% (17 of 35 hips) at latest followup (p = 0.002); the proportion of limp decreased from 76% (31 of 41 hips) to 9% (three of 35 hips; p < 0.001); the proportion of normal abductor strength increased from 17% (seven of 41 hips) to 91% (32 of 35 hips; p < 0.001); mean Merle d'Aubigné-Postel score increased from 14 ± 1.7 (range, 9-17) to 17 ± 1.5 (range, 13-18; p < 0.001); mean internal rotation increased to 25° ± 15° (range, 0°-60°; p = 0.045), external rotation to 32° ± 14° (range, 5°-70°; p = 0.013), and abduction to 37° ± 13° (range, 10°-50°; p = 0.004). Eighty percent of hips (33 of 41 hips) showed normal trochanteric height; alpha angle improved to 42° ± 10° (range, 27°-90°). Two hips (5%) had subsequent surgeries as a result of lack of containment; four of 41 hips (10%) had complications resulting in reoperation. Fourteen of 35 hips (40%) showed progression of OA; four of 40 hips (10%) converted to THA.

CONCLUSIONS

Relative femoral neck lengthening in hips with combined intra- and extraarticular impingement results in reduced pain, improved function, and improved radiographic parameters of the proximal femur. Although lack of long-term complications is gratifying, progression of OA was not prevented and remains an area for future research.

What are the demographic and radiographic characteristics of patients with symptomatic extraarticular femoroacetabular impingement?

BACKGROUND

Extraarticular femoroacetabular impingement (FAI) can result in symptomatic hip pain, but preoperative demographic, radiographic, and physical examination findings have not been well characterized.

QUESTIONS/PURPOSES

The purposes of this study were to (1) define the demographic characteristics of patients with symptomatic extraarticular FAI; and (2) identify relevant radiographic and physical examination findings that are associated with intraoperative locations of extraarticular FAI.

METHODS

For purposes of this study, we defined extraarticular FAI as abnormal contact between the extraarticular regions of the proximal femur (greater trochanter, lesser trochanter, extracapsular femoral neck) and the ilium or ischium. The diagnosis was suspected preoperatively, but it was confirmed at the time of surgery by direct visualization of extraarticular impingement after surgical hip dislocation. A prospective single-center hip preservation registry was used to retrospectively characterize patients presenting between October 2010 and November 2013 with symptomatic hip pain and intraoperative findings of extraarticular FAI (N = 75 patients, 86 hips). Detailed demographic data were recorded. Radiographs, CT, and MRI scans were reviewed for all patients by two of the authors (BFR, ELS). Outcome instruments including modified Harris hip score (mHHS), Hip Outcome Score (HOS), and International Hip Outcome Tool (iHOT-33) were assessed preoperatively. A comparison group of all patients (N = 1690 patients, 1989 hips) undergoing surgery for intraarticular FAI over the study period were included for demographic comparisons. Cases with extraarticular FAI accounted for 4% (75 of 1765 patients) of our cohort over the study time period.

RESULTS

Patients with extraarticular FAI were more likely to be younger (mean ± SD, 24 ± 7 years versus 30 ± 11 years; difference [95% confidence interval {CI}], -7 [-9 to -4]; p < 0.001), female (85% versus 49%; odds ratio [95% CI], 6 [3 to 12]; p < 0.001), to have undergone prior hip surgery (44% versus 10%; odds ratio [95% CI], 9 (6 to 15); p < 0.001), and have lower preoperative outcome scores after adjustment for age, sex, and revision status (mHHS 55 ± 15 versus 63 ± 15; adjusted difference [95% CI], -4 (-8 to -1); p = 0.017; HOS ADL 64 ± 19 versus 73 ± 18; adjusted difference [95% CI], -7 (-11 to -3); p = 0.002) than patients undergoing surgery for intraarticular FAI. Within the extraarticular FAI group, preoperative femoral version on CT was different among patients with anterior versus posterior extraarticular impingement (median [first quartile, third quartile], 8° [2, 18] versus 21° [20, 30], respectively; p = 0.005) and anterior versus complex extraarticular impingement (median [first quartile, third quartile], 8° [2, 18] versus 20° [10, 30], respectively; p = 0.007]. Preoperative external rotation in extension was increased in patients with anterior versus complex extraarticular FAI (median [first quartile, third quartile], 70° [55, 75] versus 40° [20, 60]; p < 0.001).

CONCLUSIONS

Extraarticular FAI is an uncommon source of impingement symptoms. We suspect the diagnosis often is missed, because many of these patients had prior hip surgery before the procedure that diagnosed the extraarticular impingement source. This diagnosis seems more common in younger, female patients. Radiographic and physical examination findings correspond to locations of intraoperative extraarticular impingement. Future studies will need to determine whether surgical treatment of extraarticular impingement pathology improves pain and function in this subset of patients.

Endoscopic lesser trochanter resection for treatment of ischiofemoral impingement

Ischiofemoral impingement (IFI) is an uncommon source of hip pain characterized by abnormal proximity of the lesser trochanter (LT) and the anterior border of ischium. The condition can be treated non-operatively but in severe cases, LT excision can provide beneficial results. Most previous descriptions for IFI operation use an open surgical approach but with the advancement of arthroscopic surgery, the LT can be approached less invasively. This study describes a simple endoscopic method to decompress the LT. Due to the posteromedial location of LT, this method requires careful positioning of the leg, and the use of curved type instruments is recommended. Also, it is helpful to assess the amount of resection with a properly oriented fluoroscopic view.

Diagnosis and 2-year outcomes of endoscopic treatment for ischiofemoral impingement

PURPOSE

The purposes of this study were to investigate the clinical and radiographic presentation of patients with ischiofemoral impingement (IFI) and to assess the outcomes of endoscopic treatment with partial resection of the lesser trochanter.

METHODS

Five patients with IFI who underwent endoscopic treatment with partial resection of the lesser trochanter were retrospectively reviewed. The outcomes were assessed at a mean follow-up of 2.3 years (range, 2 to 2.5 years) through the modified Harris Hip Score and a visual analog scale score for pain. Physical examination tests provoking the impingement between the lesser trochanter and ischium were used for the diagnosis of IFI, including the IFI test and reproducible pain lateral to the ischium with the long-stride walking test. The presence of quadratus femoris muscle edema and a decreased ischiofemoral space on magnetic resonance imaging was also necessary for the diagnosis.

RESULTS

The mean modified Harris Hip Score increased from 51.3 points (range, 34.1 to 73.7 points) preoperatively to 94.2 points (range, 78.1 to 100 points) at the final follow-up (P = .003). The mean visual analog scale score for pain decreased from 6.6 (range, 6 to 7.3) before surgery to 1 (range, 0 to 4) at the final follow-up (P = .001). The mean duration to return to sport after surgery was 4.4 months (range, 1 to 7 months) for the 5 patients in this study. No complication was observed.

CONCLUSIONS

The endoscopic treatment of IFI was effective at 2 years in 5 patients with consistent clinical and imaging diagnostic findings.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Arthroscopically assisted fixation of the lesser trochanter fracture: a case series

Avulsion fractures of the lesser trochanter in adolescents are uncommon. This injury is a result of a sudden forceful contraction of the iliopsoas tendon. It usually occurs during vigorous sport activity. Historically, these injuries were treated non-operatively, with guarded results, including weak hip flexor strength and non-union, hindering return to competitive sport. We report a series of three arthroscopically assisted fracture fixations performed by the senior author, using cannulated screw fixation in two cases and an anchor in one case. Mobilization was commenced immediately following surgery, allowing weight bearing as tolerated using crutches for 4 weeks, thereafter unaided walking was allowed. Patients were assessed at 2 weeks, 6 weeks, 3 months and 1-year post-operatively. Radiographs were utilized to confirm full union. All three patients were able to mobilize unaided by 4 weeks post-operatively and two of the three patients returned to competitive sport at 3 months. Near—anatomical union was achieved in all cases. No complications were noted during surgery and the peri-operative period in our series. The utilization of arthroscopic reduction and fixation of avulsion of the lesser trochanter results in good fixation and allows a faster recovery with a return to sports activity, and therefore, we suggest it as a viable treatment option for such injuries.

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.