Ischiofemoral Impingement Syndrome

Written by: Dr Jeremy Steinberg – created: 16 April 2023; last modified: 11 April 2025

This article is still missing information.

Mild oedema in the right ischiofemoral space along with hamstring origin low grade tears.
Ischiofemoral Impingement Syndrome
Epidemiology	Uncommon
Causes	Multifactorial, stemming from anatomical contributions (pelvic/femoral morphology like coxa valga or increased anteversion), dynamic functional factors (muscle imbalance, altered kinematics), and potentially iatrogenic changes following hip surgery.
Pathophysiology	Repetitive mechanical compression or shearing of the Quadratus Femoris muscle within a narrowed ischiofemoral or quadratus femoris space leads to edema, inflammation, tears, and eventual fatty infiltration or atrophy, potentially causing secondary sciatic nerve irritation.
Classification	Extra-articular hip impingement condition.
Clinical Features	Clinical features include localized pain in the lower buttock, groin, or inner thigh, frequently accompanied by mechanical sensations (snapping, clicking) during ambulation, particularly with longer strides, and potentially radiating sciatic-like symptoms.
Tests	MRI to visualise quadratus femoris oedema. Diagnostic injection may be used
Treatment	Physical therapy and activity modification. Surgery for refractory cases.

Ischiofemoral Impingement (IFI) syndrome is an uncommon cause of posterior hip pain. Historically, IFI was first described in patients following hip surgery, such as total hip arthroplasty (THA) or proximal femoral osteotomy. However, clinical awareness has expanded, and IFI is now identified in native, non-operated hips. Characteristic symptoms often include pain localized to the lower buttock, groin, or inner thigh, often with mechanical symptoms like snapping, clicking, or locking particularly with longer strides.

Anatomy

The fundamental pathology underlying IFI involves a dimensional reduction, or narrowing, of the anatomical space situated between the lateral aspect of the ischial tuberosity and the medial aspect of the lesser trochanter. This critical interval is termed the ischiofemoral space (IFS).

Relevant Structures:

• Ischial Tuberosity: Located on the posteroinferior aspect of the ischium, which forms the lower and back part of the hip bone (os coxa), the ischial tuberosity serves as the prominent "sitting bone". It is a critical attachment site for the hamstring muscle group origin (semitendinosus, semimembranosus, biceps femoris long head) and the origin of the QFM. Its lateral border forms the medial boundary of the IFS.
• Lesser Trochanter (LT): This conical bony prominence is situated on the posteromedial aspect of the proximal femur, at the base of the femoral neck. It serves as the primary insertion point for the conjoined iliopsoas tendon, the major flexor of the hip. The medial cortex of the LT forms the lateral boundary of the IFS.
• Quadratus Femoris Muscle (QFM): This flat, quadrilateral-shaped muscle originates from the lateral aspect of the ischial tuberosity, just anterior to the semimembranosus origin , and inserts onto the quadrate tubercle on the intertrochanteric crest of the femur. It lies directly within the IFS, between the ischium and the LT. Functionally, the QFM is a powerful external rotator of the hip and also assists with hip adduction. Its anatomical neighbors include the obturator externus muscle anteriorly, the sciatic nerve posteriorly, the inferior gemellus muscle superiorly, and the adductor magnus muscle inferiorly.

Pathophysiology

When the IFS narrows beyond a certain threshold, it leads to the mechanical compression, entrapment, or impingement of the soft tissue structures residing within or passing through this space. The primary structure affected is the Quadratus Femoris muscle (QFM), which traverses the IFS. Repetitive or sustained compression of the QFM results in a cascade of pathological changes, including edema, inflammation, partial or full-thickness tears, and, in chronic cases, fatty infiltration and atrophy. Due to the close anatomical proximity of the QFM to the sciatic nerve posteriorly, inflammation or edema of the muscle can also lead to secondary irritation of the nerve, producing radiating pain or neurological symptoms mimicking sciatica.

A critical consideration in interpreting IFS measurements is the significant discrepancy between static imaging (typically supine MRI) and the dynamic reality of hip function. The IFS narrows considerably during specific movements, particularly hip extension, adduction, and external rotation. Static MRI measurements obtained in a neutral, non-weight-bearing position significantly overestimate the minimum space available during functional activities like walking.

Risk Factors

Anatomical Factors

The development of IFI often results not from a single gross anatomical abnormality, but rather from the convergence of multiple, potentially subtle, anatomical variations in both the pelvis and the femur. For instance, the combination of coxa valga and increased femoral anteversion, both independently linked to IFI, frequently occurs together, potentially having an additive effect on IFS narrowing. Similarly, the anatomical profile of the female pelvis involves several factors (wider relative shape, increased ischial angle, smaller femoral offset) that collectively predispose to a smaller IFS. This concept of cumulative risk suggests that clinicians should assess multiple morphological parameters rather than focusing on a single measurement.

Table 1: Summary of Anatomical Variations and their Effect on Narrowing of the IFS

Anatomical Factor	Variations causing IFS Narrowing	Potential Clinical Implication
Pelvic	Female Sex	Higher baseline risk in females due to obstetric adaptations.
	Increased Ischial Angle	Wider pelvic outlet associated with reduced IFS.
	Pelvic Retroversion (Functional Tilt)	Posterior pelvic tilt may approximate ischium and LT.
	Ischial Tuberosity Enlargement (Post-Trauma)	Direct encroachment on space.
Femoral	Coxa Valga (Increased Neck-Shaft Angle)	Alters hip mechanics, associated with IFI.
	Increased Femoral Anteversion	Positions LT more posteriorly, independent predictor of IFI.
	Decreased Femoral Offset	Reduces space between femur and pelvis, common in females.
	Prominent/Enlarged Lesser Trochanter	Direct encroachment on space.
	Developmental Hip Dysplasia (DDH)	Associated altered anatomy can reduce IFS.
	Intertrochanteric Fracture Malunion	Altered proximal femoral geometry.
Iatrogenic	THA (esp. with decreased offset)	Altered surgical anatomy reduces space.
	Valgus Proximal Femoral Osteotomy	Surgical alteration increases valgus, potentially narrowing IFS.
	Knee Valgisation Osteotomy	Induces relative femoral adduction, reducing IFS.

Functional Factors

Beyond static anatomical structure, the manner in which the hip and pelvis function dynamically during movement plays a pivotal role in the pathogenesis of IFI. Functional biomechanical factors, including muscle imbalances, altered joint kinematics, and instability, often interact with underlying anatomical predispositions to precipitate or exacerbate impingement. These dynamic elements explain why individuals with similar anatomy may have vastly different clinical presentations and why symptoms are often activity-dependent.

A critical functional pathway likely contributing to many cases of IFI involves a cascade initiated by hip abductor weakness. Insufficient abductor strength or endurance compromises pelvic stability during the single-leg support phase of gait. This leads to inadequate control of the femur in the frontal plane, resulting in excessive dynamic hip adduction. When this occurs concurrently with the hip extension required during terminal stance, it creates the precise kinematic environment (extension + adduction ± external rotation) known to cause maximum narrowing of the IFS. This repetitive dynamic compression during each gait cycle leads to cumulative trauma and subsequent pathology in the QFM. This chain of events – abductor weakness leading to altered gait kinematics resulting in dynamic IFS narrowing – provides a compelling biomechanical explanation for the development of IFI in individuals who may or may not have significant static anatomical predispositions.

Table 2 Functional Biomechanical Factors

Functional Factor	Specific Example	Biomechanical Consequence	Potential Treatment Target
Muscle Imbalance	Hip Abductor Weakness (Glut Med/Min)	Uncontrolled Hip Adduction, Pelvic Drop (Trendelenburg)	Strengthening Hip Abductors
	Adductor/Hamstring Tightness	Altered Hip Mechanics, Potential QFS Narrowing (Hamstring)	Stretching Adductors/Hamstrings (if tight & non-provocative)
	Hip Flexor Tightness	Limited Hip Extension, Compensatory Lumbar Extension/Pelvic Tilt	Stretching Hip Flexors
Altered Kinematics	Excessive Hip Extension/Adduction/ER during Gait	Dynamic IFS Narrowing, Repetitive QFM Compression	Gait Retraining, Activity Modification
	Long Stride Length	Increased time/magnitude of Hip Extension	Gait Retraining (shorter strides)
	Reduced Hip Extension (Compensation)	Increased Lumbar Extension/Loading	Addressing Primary Hip Limitation, Core/Spinal Stabilization
Instability	Hip Instability	Aberrant Femoral Head Motion, Compensatory Muscle Guarding	Neuromuscular Control Exercises, Strengthening
	Pelvic/Core Instability	Poor Transfer of Forces, Compensatory Hip Movements	Core Strengthening, Lumbopelvic Stabilization
	Hip-Spine Syndrome Interaction	Mutual Reinforcement of Hip and Spine Dysfunction	Integrated Hip and Spine/Pelvic Rehabilitation

Furthermore, the relationship between IFI and broader biomechanical dysfunction may be bidirectional. While functional deficits like abductor weakness or instability can precipitate IFI, the presence of IFI itself can subsequently drive further compensatory problems. The pain and mechanical block associated with IFI often lead to a limitation in hip extension. This restricted hip motion necessitates compensatory adjustments elsewhere in the kinetic chain, most notably increased extension and loading through the lumbar spine (hip-spine syndrome). This creates a potential vicious cycle where hip pathology contributes to spinal dysfunction, and altered spinal mechanics might further influence pelvic positioning and hip function. This highlights the importance of assessing and potentially treating associated dysfunction in adjacent regions, particularly the lumbar spine and pelvis, when managing patients with IFI.

Clinical Features

The patient should have posterior inferior buttock pain and localised tenderness over the quadratus femoris muscle. Test provocative maneuvers that replicate the positions of maximal IFS narrowing - extension, adduction, external rotation; long-stride walking test.

Differential Diagnosis

Differential Diagnosis of Buttock Pain

Differential Diagnosis

• Lumbosacral spine
  • Referred Lumbar Spine or Sacroiliac Joint pain
• Hip joint causes
  • Hip joint osteoarthritis
  • Other hip joint causes
• Extra-articular hip causes
  • Gluteus medius and/or minimus tendinopathy
  • Hamstring origin tendinopathy, or origin avulsion injury
  • Lateral rotator tendinopathy
  • Ischiogluteal bursitis
  • Ischiofemoral Impingement Syndrome
  • Myofascial pain
• Nerve entrapment
  • Sciatic or pudendal nerve entrapment
• Other
  • Posterior thigh compartment syndrome
  • Sacral Insufficiency Fracture
• Spondyloarthritis
• Malignancy
• Bone and joint infection

Treatment

Injections

Main article: Quadratus Femoris Injection

While interventions like image-guided corticosteroid injections into the IFS or QFM can provide diagnostic information and temporary symptomatic relief, they are not a long term management strategies as they do not address the underlying pathomechanics of the impingement and hence the pain usually returns when the steroid wears off in 2-3 months. The diagnostic value is more important than the therapeutic value.

Activity Modification

Activities that dynamically narrow the IFS are those that combine hip extension, adduction, and external rotation. Common triggers and how to address them include:

• Walking/Running: Especially with long strides (increasing hip extension), running uphill (requiring greater hip extension/power), or running on uneven surfaces (challenging pelvic stability). Consciously shorten stride length during walking and running to limit terminal hip extension. Focus on maintaining a level pelvis and avoiding excessive hip adduction or trunk lean.
• Sitting: Prolonged sitting, particularly in low chairs or with legs crossed (combining flexion/adduction/rotation), can sometimes aggravate symptoms, possibly through sustained pressure or secondary effects. Use a cushion (e.g., wedge or donut cushion) to offload the ischial tuberosity region, avoid low chairs, ensuring feet are flat on the floor, avoiding crossing legs, and take frequent breaks from prolonged sitting.
• Specific Exercises/Movements: Deep squats (if involving excessive adduction/rotation), lunges (particularly the trail leg involving extension), stair climbing, certain yoga poses (e.g., pigeon pose, deep external rotation poses), rowing machine use (requires repeated hip extension), and kicking motions. Adjust the range of motion during exercise (e.g. shallower squats and lunges), widen stance during squats.
• Direct Pressure: Sitting directly on the ischial tuberosity area, especially on hard surfaces. Avoidsleeping positions that place the hip in combined extension/adduction/rotation (e.g., sleeping prone with one leg abducted/externally rotated).

Physical Therapy

Physiotherapy should be trialed for a minimum of 3 months before considering surgery. A truly corrective approach aims to mitigate or resolve the biomechanical factors identified in the preceding sections (anatomical influences where adaptable, and functional deficits). The primary goals of biomechanically focused conservative care are to restore optimal non-impinging hip range of motion, correct muscle imbalances (improve flexibility of tight structures, strengthen weak muscles), improve neuromuscular control, optimise movement patterns, and address any hip-spine syndrome contribution.

Given the multifactorial nature of IFI and the variability in patient presentations, a standardized, "cookbook" approach to physical therapy is unlikely to be effective. Individualization is paramount.

Stretching: To restore normal tissue length in muscles whose tightness may restrict physiological hip motion or contribute to compensatory movements that narrow the IFS.

Commonly targeted muscles for stretching include: hip flexors (to allow adequate extension), hip adductors (to allow adequate abduction), hamstrings (avoid aggressive stretching though), short external rotators (if limiting internal rotation). It is important to perform stretching in pain-free ranges and avoid positions that reproduce impingement symptoms.

Strengthening: To address muscle weakness, particularly in key stabilizers, thereby improving dynamic control of the hip and pelvis, reducing compensatory movements, and potentially unloading impinged structures. Rehabilitation typically progresses from exercises focusing on isolated muscle activation and low-load endurance in non-provocative positions towards more challenging, integrated exercises in weight-bearing and functional positions.

Commonly targeted muscles include: hip abductors (to address strong link between abductor weakness and IFI), hip external rotators and gluteus maximus (counteract excessive internal rotation tendences), core stabilisation (provide stable base for hip movement and mitigate excessive lumbopelvic motion), hip extensors (to control pelvic tilt), hip flexors (cautious)

A consistent theme across rehabilitation approaches for hip impingement syndromes is the emphasis on core and lumbopelvic stabilization. This likely reflects the critical need for a stable proximal foundation (trunk and pelvis) to enable optimal hip joint function and control. (See Dynamic Neuromuscular Stabiliation). Strengthening the core musculature helps manage forces transmitted through the kinetic chain and may reduce the reliance on compensatory movements at the hip or lumbar spine, particularly relevant in the context of potential hip-spine syndrome interactions.

Neuromuscular Re-education and Gait Training: To integrate strength and mobility gains into improved automatic control and coordination during functional activities, particularly walking, thereby reducing the dynamic stresses that lead to impingement.

Balance training includes exercises challenging the patient's ability to sense and control joint position and maintain equilibrium. Examples include single-leg stance variations (eyes open/closed, stable/unstable surfaces). Movement pattern retraining includes addressing specific faults such as knee valgus during squats and pelvic drop during single leg stance. Gait training includes cueing for shorter stride length to minimise terminal hip extension and control of pelvic stability to prevent excessive drop. Table 3: Example Physical Therapy Protocol Components for IFI (Biomechanical Focus)

Phase	Goals	Example Stretching Exercises (Target & Technique)	Example Strengthening Exercises (Target & Technique)	Neuromuscular/Functional Exercises	Notes/Precautions
Phase 1: Pain/Inflammation Control & Initial Activation (Weeks 0-4, variable)	Reduce pain/inflammation, protect irritated tissues, initiate gentle mobility in non-provocative ranges, activate inhibited muscles, establish basic core control.	Gentle, pain-free AAROM/AROM hip flexion, abduction, IR. Avoid provocative EROM/add/ext. Potential gentle static holds: Kneeling hip flexor (avoid deep extension), supine adductor (butterfly, caution), piriformis (supine figure-4, avoid deep ER/add). Focus on tissue tolerance.	Isometric glute activation (squeeze), Isom abd/add/ext in neutral. Core: Pelvic tilts, TA activation (abdominal bracing/hollowing), gentle heel slides. Hip Abductors: Low-load clamshells (limited range), side-lying hip abduction (limited range, neutral hip) . Ext Rot: Clamshells. Glute Max: Gentle bridges (low height, double leg)	Minimal at this stage. Focus on controlled muscle activation and pain-free movement within restricted ranges. Basic postural awareness education.	Strict avoidance of provocative positions/activities. Modalities (ice/heat) prn. Focus on quality of activation, not high load. Emphasize pain-free exercise. Activity modification critical.
Phase 2: Restore Mobility & Build Foundation (Weeks 4-8, variable)	Gradually increase non-impinging ROM, improve muscle endurance & strength, enhance core stability, begin basic balance/proprioception.	Progress stretches as tolerated, maintaining pain-free ranges: Hip Flexor (Thomas test position), Adductor (side-lying stretch), Hamstring (supine SLR, gentle), Piriformis/ER (seated figure-4). Foam rolling (TFL, Adductors, Glutes, Hamstrings) if helpful & non-provocative.	Core: Progress planks (knees/toes, short holds), side planks (knees/short lever), dead bug variations. Hip Abductors: Increase reps/hold time for side-lying abduction/clamshells, add light resistance band, Standing hip abduction (no lean), Hip hikes. Ext Rot: Progress clamshell resistance, Fire hydrants. Glute Max/Ext: Progress bridges (higher, holds, single leg support), Quadruped hip extension.	Basic balance: Tandem stance, single leg stance (short holds, stable surface). Weight shifts. Introduction to controlled bodyweight squat (limited depth, focus on form/pelvic control).	Continue avoiding end-range provocative movements. Monitor symptom response closely. Focus on proper form and control over quantity. Gradually increase hold times/reps before resistance.
Phase 3: Strength & Functional Integration (Weeks 8-12+, variable)	Achieve full pain-free ROM (non-impinging), normalize muscle strength, improve dynamic stability & control, begin integrating into functional movements.	Maintain flexibility program as needed. Focus on dynamic/functional ROM.	Core: Progress planks/side planks (longer holds, dynamic variations), Advanced dead bug/bird-dog variations. Hip Abductors: Lateral band walks, Standing abduction with resistance, Step-downs (focus on pelvic control). Ext Rot: Standing band ER, Cable ER. Glute Max/Ext: Hip thrusts (weighted), RDLs (form focus), Lunges (controlled depth). Adductors: Side plank with adduction, Copenhagen planks (modified).	Balance: Progress SLS (unstable surface, eyes closed, perturbations). Dynamic balance: Star excursions, step-ups, single leg squats (controlled). Gait retraining: Cueing for stride length, pelvic control, glute activation. Introduction to low-level plyometrics (if appropriate/pain-free).	Emphasize quality of movement over load. Ensure proper lumbo-pelvic control during all functional exercises. Gradually re-introduce modified sport/activity specific movements.
Phase 4: Return to Activity/Sport (Ongoing)	Maintain strength/control, safely return to desired activities/sport, implement injury prevention strategies.	Continue maintenance flexibility program.	Continue progressive strengthening focused on functional demands and identified weaknesses. Periodized training principles.	Sport/activity-specific drills with focus on biomechanics. Agility drills. Plyometrics. Continued gait refinement.	Monitor for symptom recurrence. Gradual increase in intensity/volume of activity. Emphasize proper warm-up/cool-down and ongoing self-management strategies (e.g., activity modification).

Surgery

Arthroscopic surgery was shown to be superior to physical therapy, although there are no sham controlled studies and both interventions improved hip related quality of life. Surgical options include endoscopic lesser trochanter resection, ischial tuberosity resection, quadratus femoris debridement, proximal femoral osteotomy.

Resources

Ischiofemoral Impingement Syndrome - Members Subpage

Ischiofemoral Impingement Syndrome - Wu 2023.pdf - 9.88 MB (f)

IFI protocol FASHIoN 2016.pdf - 961 KB (f)

Literature Review

Literature Review

Reviews from the last 7 years: review articles, free review articles, systematic reviews, meta-analyses, NCBI Bookshelf

Articles from all years: PubMed search, Google Scholar search.

TRIP Database: clinical publications about evidence-based medicine.

Other Wikis: Radiopaedia, Wikipedia Search, Wikipedia I Feel Lucky, Orthobullets,