Hip impingement, also known as femoroacetabular impingement (FAI), occurs when the ball and socket of the hip joint don’t fit together smoothly, causing the bones to rub against each other and potentially damage the cartilage and labrum during movement.
It typically develops from bone abnormalities that form during childhood and adolescence, with symptoms often appearing later in young to middle-aged adults, particularly those with repetitive hip flexion from sports or prolonged sitting.
Without appropriate management, the repetitive friction may gradually wear down cartilage and potentially contribute to earlier onset of hip osteoarthritis.
Types of Hip Impingement
Hip impingement presents in three distinct forms, each characterised by different bone abnormalities that cause the joint surfaces to collide.
Cam Impingement
Cam impingement develops when the femoral head isn’t perfectly round. Instead of a smooth spherical surface, an extra bump of bone forms at the junction between the femoral head and neck. During hip flexion, this bony protrusion jams against the acetabular rim rather than rotating freely within the socket. The abnormal contact shears the cartilage from the underlying bone, typically affecting the front-upper portion of the socket. Cam impingement is strongly associated with high-impact sports participation during adolescence.
Pincer Impingement
Pincer impingement results from excessive coverage of the femoral head by the acetabulum. The socket rim extends too far over the ball, or the entire socket is angled in a way that provides overcoverage. When the hip flexes, the femoral neck strikes against this overhanging rim, crushing the labrum between the two bones. Over time, the labrum degenerates and may ossify, further deepening the socket and worsening the impingement. Pincer impingement typically affects the labrum before damaging the articular cartilage.
Mixed Impingement
Most individuals with hip impingement have features of both cam and pincer morphology. The combination can accelerate joint damage because both the femoral head and acetabular rim contribute to abnormal contact. Mixed impingement requires assessment of both components when planning treatment.
Recognising Hip Impingement Symptoms
Hip impingement symptoms develop gradually and often go unrecognised until the condition has progressed significantly. The pain pattern and specific triggers can help distinguish FAI from other hip conditions.
Pain location and character
- Groin pain is the classic presentation, often described using the “C-sign,” cupping the hand around the front and side of the hip
- Pain may radiate to the thigh, buttock, or lower back
- Sensation ranges from a sharp catch during certain movements to a deep, dull ache after activity
Provocative activities
- Symptoms typically worsen with deep hip flexion, internal rotation, or both
- Sitting for extended periods, especially in low chairs or car seats, commonly aggravates pain
- Rising from a seated position, climbing stairs, squatting, and pivoting can trigger symptoms
- Athletes often notice pain during movements like kicking, sprinting, or quick directional changes
Stiffness and mechanical symptoms
- Morning stiffness or stiffness after prolonged sitting is common
- Some individuals experience clicking, catching, or locking sensations in the hip
- These mechanical symptoms may suggest labral involvement
Activity modification
- Many people unconsciously alter movement patterns to avoid painful positions
- Difficulty putting on shoes and socks, or getting in and out of cars, is common
- Exercises that previously caused no discomfort may become harder to perform
What Causes Hip Impingement?
The bone abnormalities underlying hip impingement form during skeletal development, though the exact mechanisms remain under investigation.
Developmental factors: The shape of the femoral head and acetabulum is largely determined during growth. High-intensity athletic training during adolescence, particularly sports involving repetitive hip flexion and rotation, appears to influence bone development.
The growing skeleton responds to mechanical stress by adding bone in areas of high load, potentially contributing to a cam deformity. Genetic predisposition may also play a role, with hip impingement showing familial clustering.
Anatomical variations: Some individuals are born with hip socket orientations that predispose to pincer impingement. Conditions like hip dysplasia, Legg-Calvé-Perthes disease, and slipped capital femoral epiphysis during childhood can alter hip anatomy and increase impingement risk.
Activity patterns: While bone morphology sets the stage, repetitive movements can trigger symptoms. The combination of anatomical predisposition and activity demands generally determines who develops symptomatic impingement. Someone with mild cam morphology may remain symptom-free with low-demand activities but develop pain when taking up a sport requiring extreme hip positions.
💡Did You Know?
Cam morphology typically begins developing around ages 12 to 13 and continues to increase during the adolescent growth spurt, generally stabilising once the growth plate closes. The bone shape present in adulthood was largely established during this period of skeletal growth.
Diagnostic Approach
Accurate diagnosis requires correlating clinical findings with imaging results, as bone abnormalities visible on imaging don’t always cause symptoms.
Clinical Examination
Physical examination assesses hip range of motion, identifies painful movements, and helps rule out other conditions. The FADIR impingement test, flexing the hip to 90 degrees, then adducting and internally rotating it while applying gentle pressure, often reproduces the patient’s pain when FAI is present. The examiner also evaluates core muscle function, spinal mobility, and the opposite hip, as these factors influence treatment planning.
Imaging Studies
X-rays reveal the bone abnormalities characteristic of hip impingement. Specific views demonstrate cam deformities, pincer overcoverage, and signs of early arthritis. Measurements of the alpha angle (quantifying cam severity) and centre-edge angle (quantifying acetabular coverage) help characterise the impingement pattern.
MRI with arthrography provides detailed assessment of the labrum and cartilage, soft tissue structures not well visualised on X-rays. An injection of contrast material into the joint improves visualisation of labral tears and cartilage damage. MRI findings help guide treatment decisions by revealing the extent of joint damage.
CT scans offer three-dimensional reconstruction of bone anatomy, useful for surgical planning when complex deformities are present.
⚠️ Important Note
Imaging abnormalities don’t automatically indicate the need for treatment. Many individuals with cam or pincer morphology on X-rays never develop symptoms. Treatment decisions should be based on clinical symptoms, functional limitations, and imaging findings together, not imaging alone.
Conservative Treatment Options
Non-surgical management serves as first-line treatment for most patients with hip impingement, aiming to reduce symptoms and improve function through activity modification and targeted rehabilitation.
Activity Modification
Identifying and temporarily avoiding movements that provoke symptoms allows irritated tissues to settle. This doesn’t mean complete rest; rather, it typically involves substituting aggravating activities with alternatives that maintain fitness without stressing the hip. For athletes, this may mean reducing training intensity, modifying technique, or cross-training with low-impact activities like swimming or cycling with appropriate seat height.
Physiotherapy
A structured rehabilitation programme addresses muscle imbalances, movement patterns, and hip stability. Core and gluteal strengthening may help reduce abnormal loads on the hip joint. Manual therapy techniques may improve hip mobility within the available pain-free range. The physiotherapist also guides gradual return to activity, aiming to ensure the hip can tolerate progressive demands.
Medications and Injections
Anti-inflammatory medications may help manage acute symptom flares. Corticosteroid injections into the hip joint can provide temporary relief and may help confirm the hip as the pain source when diagnosis is uncertain. While injections don’t address the underlying bone abnormality, they may facilitate participation in physiotherapy by reducing pain during exercises.
Expected Outcomes
Conservative treatment effectively manages symptoms in many patients, particularly those with mild anatomical abnormalities or low activity demands. However, it cannot reverse existing cartilage damage or change bone shape. Patients who do not improve after several months of dedicated conservative management may be candidates for surgical intervention.
Surgical Treatment
Hip arthroscopy is a surgical approach for hip impingement, allowing bone reshaping and soft tissue repair through small incisions.
Arthroscopic Surgery
Using specialised instruments inserted through two to three small portals, the surgeon reshapes the femoral head-neck junction (for cam impingement) and trims the overhanging acetabular rim (for pincer impingement). The damaged labrum can be repaired or reconstructed. Loose cartilage is removed, and microfracture techniques may stimulate fibrocartilage formation in areas of full-thickness cartilage loss.
The hip arthroscopy typically takes one to two hours. Most patients go home the same day, using crutches for several weeks to protect the repair. Rehabilitation following surgery is a gradual process moving from protected motion to strengthening to sport-specific training, and return to sport commonly ranges from around five to ten months depending on the individual and the demands of their activity.
Open Surgery
Complex deformities or advanced cartilage damage may require open surgical approaches, including surgical hip dislocation for complete access to the joint. Open surgery allows more extensive bone reshaping and cartilage procedures but involves a longer recovery.
When Surgery May Not Help
Significant pre-existing arthritis limits the benefit of impingement surgery. If cartilage damage has progressed beyond a certain threshold, addressing the bone abnormality is unlikely to restore a healthy joint surface. Patients with advanced arthritis may benefit more from joint preservation alternatives or eventual hip replacement. Preoperative imaging and clinical assessment help identify who is likely to benefit from arthroscopic intervention.
Recovery and Rehabilitation
Recovery following hip impingement surgery generally follows a structured progression designed to protect healing tissues while restoring function.
Weeks one to four: Protected weight-bearing with crutches. Gentle range of motion exercises aim to prevent stiffness while respecting tissue healing constraints. Hip flexion is typically limited during this phase.
Weeks four to eight: Progressive weight-bearing toward walking without crutches. Stationary cycling and pool exercises may supplement land-based rehabilitation. Muscle activation exercises begin.
Months two to four: Strengthening intensifies. Normal walking pattern is generally restored. Low-impact conditioning activities may resume.
Months four to ten: Sport-specific training begins for athletes, with many requiring closer to six to ten months before a full return to competitive sport. Return depends on strength testing and functional assessment rather than time alone.
✅ Quick Tip
Adhering to post-operative restrictions during the first six weeks may help support surgical outcomes. Protecting the labral repair while it heals to bone supports long-term joint stability.
Living with Hip Impingement
Whether managed conservatively or surgically, certain strategies can help maintain hip health over the long term.
Movement awareness: Understanding which positions stress the hip allows for informed choices during daily activities and exercise. Avoiding deep squatting, minimising prolonged sitting, and using proper technique during physical activity may help reduce cumulative joint stress.
Maintaining hip strength: Strong muscles around the hip can help absorb forces that would otherwise load the joint surfaces. Continued commitment to hip and core strengthening exercises, even after formal rehabilitation ends, may help protect the joint.
Weight management: Maintaining a healthy weight may help reduce mechanical stress on the joint.
Appropriate activity selection: Some activities are generally more hip-friendly than others. Swimming, cycling, and elliptical training provide cardiovascular benefits with minimal impact. High-impact sports can often be continued with appropriate training modifications and attention to recovery.
When to Seek Professional Help
Consider orthopaedic evaluation if you experience:
- Groin or hip pain lasting more than several weeks despite rest
- Pain that limits your ability to walk, sit, or sleep comfortably
- Hip stiffness affecting daily activities like dressing or getting into a car
- Clicking, catching, or locking sensations in the hip
- Inability to participate in exercise or sports due to hip symptoms
- Pain that has progressively worsened over time
Commonly Asked Questions
Can hip impingement heal on its own?
The bone abnormalities causing hip impingement don’t resolve spontaneously; they represent the established shape of the joint. However, symptoms can improve significantly with conservative management. Activity modification, physiotherapy, and time often reduce pain and restore function, particularly in those with mild morphological abnormalities. The goal of non-surgical treatment is symptom management rather than anatomical correction.
How long does recovery from hip arthroscopy take?
Most patients walk without crutches within four to six weeks and return to desk work within two to three weeks. Many report meaningful functional improvement by four to six months, though published return-to-sport data more typically ranges from five to ten months, with some athletes needing closer to a year depending on the sport and the extent of surgery. Individual timelines vary based on the procedures performed, tissue quality, and rehabilitation compliance.
Will hip impingement lead to arthritis?
Untreated hip impingement can accelerate cartilage wear, potentially leading to osteoarthritis. However, the progression varies considerably between individuals. Some people with FAI morphology never develop significant arthritis, while others progress more rapidly. Early treatment aims to reduce abnormal joint contact and preserve remaining cartilage, though it cannot reverse existing damage.
Can I continue exercising with hip impingement?
Yes, often with modifications. Avoiding positions of deep hip flexion and impact loading while symptoms are active can help you maintain fitness. Swimming, cycling with appropriate seat height, and upper body exercises typically don’t aggravate symptoms. Working with a physiotherapist helps identify which activities are safe and how to modify problematic exercises.
Is hip impingement common in young adults?
FAI morphology is present in a notable proportion of the population, though not everyone develops symptoms. Symptomatic hip impingement commonly presents in active individuals during their twenties and thirties. The combination of underlying bone shape and activity demands generally determines who develops clinical problems.
Next Steps
Hip impingement evaluated before significant cartilage damage develops allows for a wider range of management options, as early assessment helps determine whether conservative rehabilitation or surgical intervention is appropriate. For patients who do require surgery, outcomes depend significantly on the baseline state of joint cartilage. Maintaining core and hip stability remains integral to joint function regardless of the treatment approach selected.
If you are experiencing persistent groin pain, hip stiffness, clicking or catching sensations, or difficulty with activities requiring hip flexion, a consultation with an orthopaedic surgeon can help assess your joint condition and determine suitable treatment options.
