Pelvic Prime's Anatomy Academy Series
Non-Arthritic Hip Pain
Understanding the Sources and Mechanics of Hip Pain
Hip pain can come from different sources, including non-musculoskeletal issues, the lower back, inside the hip joint, and areas around the hip. Often, problems in the lower back and areas around the hip occur with issues inside the hip joint. To understand hip pain, it's important to know how the spine, pelvis, hip joint, and lower body work together. This includes knowing about the labrum, cartilage, and bones in the hip, and the muscles and ligaments that support the hip.
Strong muscles and good nerve control in the lower back and pelvis are needed to keep the hip stable and to move the pelvis correctly when standing or walking. The gluteus medius and gluteus minimus muscles help control the pelvis when standing on one leg, while the gluteus maximus stabilizes the hip in multiple directions. The hip flexor muscles also help keep the hip stable during activities. Additionally, other muscles like the external rotators stop the hip from rotating too much inward, and muscles like the transversus abdominis and pelvic floor muscles provide stability by increasing pressure inside the abdomen.
Hip joint pain not caused by arthritis includes issues such as:
Femoroacetabular impingement syndrome (FAIS)
Hip dysplasia (refers to abnormalities in the shape and orientation of the hip socket (acetabulum), which can lead to hip pain and instability
Hip instability: Labral tears, Cartilage damage, Loose bodies
Ligamentum teres tears.
Experts recommend starting with nonsurgical treatments, like physical therapy, for many patients with this type of hip pain. Pain relievers, like anti-inflammatory drugs, are often suggested, but there's not much evidence showing they work well for nonarthritic hip pain. These drugs can also have serious side effects, like a higher risk of stomach bleeding.
1. Femoroacetabular Impingement Syndrome (FAIS)
Femoroacetabular impingement happens when the femur and acetabulum (hip socket) don't fit together properly, causing early contact and pain during movement. This can be due to bony abnormalities in the hip. Femoroacetabular impingement is diagnosed when there are symptoms, clinical signs, and imaging findings of these abnormalities. Recent evidence suggests that both hip dysplasia and hip impingement are linked to the development of hip osteoarthritis.
Cam-type femoroacetabular impingement is more common in young athletes
Pincer-type femoroacetabular impingement is more common in middle-aged women.
Patients with hip impingement exhibited slower walking speeds, longer times to ascend stairs, and longer times to stand up from sitting. For people with Femoroacetabular Impingement Syndrome physical therapy has been shown to help. Studies suggest at least 3 months of exercise-based therapy. These studies found that physical therapy, which includes muscle strengthening, manual therapy, and movement training, can improve outcomes.
Timing of femoral impingement surgery showed that patients who had surgery within 3 to 6 months of symptom onset had better outcomes than those who waited longer. Those with symptoms for more than 2 years before surgery had worse outcomes after 5 years.
Femoral Neck Abnormalities
The angle and rotation of the femur bone affect how the hip joint functions. The femoral neck usually connects to the femur at a 125-degree angle.
Angles above 130 degrees are called coxa valga
Angles below 120 degrees are coxa vara.
These conditions can affect the pressure on the hip joint and cause various problems.
Femoral Version
Femoral version describes the rotation of the femur. Normally, the femur is slightly anteverted (rotated forward). Excessive anteversion or retroversion changes how the hip joint moves and can increase the risk of instability or impingement.
Arthroscopic osteoplasty is a common surgery for femoral impingment. Repairing the acetabular labrum, rather than removing it, is becoming more common and seems to give better results. In cases with severe labral damage or previous surgeries, labral reconstruction might be needed.
2. Hip Dysplasia / Acetabular Dysplasia
Hip dysplasia is a term used to describe various changes in the shape and orientation of the hip socket. Developmental Dysplasia of the Hip (DDH) usually refers to hip problems that start shortly after birth or in children. In this review, hip dysplasia will refer to changes in the direction or shape of the acetabulum.
Acetabular dysplasia can be complex and involve many different factors. It can cause hip pain due to structural instability and increased pressure on the hip joint during activities. One type of acetabular dysplasia involves a shallow hip socket, which is a known cause of hip pain in young adults. Borderline dysplasia is a less severe form of this condition, causing similar symptoms but is harder to define. Recent evidence suggests that both hip dysplasia and hip impingement are linked to the development of hip osteoarthritis.
There's not much research on how well nonsurgical treatments work for hip dysplasia. The severity of hip dysplasia might affect when surgery is needed and how useful physical therapy is. For example:
A study looked at 713 patients over about 2.6 years. They found that over half of the hips studied didn't need surgery within a year. Factors like younger age, longer pain duration, worse physical function, and specific diagnoses made surgery more likely.
Labral tears and certain hip angles also increased the chance of needing surgery.
Since 2014, there's more evidence supporting periacetabular osteotomy (PAO) for treating hip dysplasia. A recent study found that over 70% of athletes returned to sports after PAO surgery.
Acetabular Depth
A shallow acetabulum can cause hip pain by not covering the femoral head properly, leading to increased stress on the hip joint. This condition is more common in women and has several risk factors like breech position during pregnancy, being a firstborn, and family history. It can also be linked to conditions like ligament laxity and changes in collagen and estrogen metabolism.
Acetabular Version
Acetabular version refers to the direction the hip socket faces. Normally, the hip socket has about 20 degrees of anteversion (facing slightly forward). Retroversion occurs when the hip socket faces backward, leading to different stress patterns on the hip joint. Acetabular retroversion can increase the risk of hip problems and is found in about 20% of patients with hip arthritis. Increased acetabular anteversion (facing too far forward) decreases the coverage of the femoral head, causing instability.
3. Hip Instability (Labral Tears, Cartilage damage, Loose bodies)
Hip instability occurs when the hip joint moves too much, causing pain and functional problems. This can happen due to structural issues in the bones or soft tissues, or a combination of both. Conditions like acetabular dysplasia or changes in femoral structure can lead to instability. Soft tissue problems, like ligament laxity, can also cause instability, especially in activities that involve repetitive hip movements.
For hip instability due to loose ligaments, procedures to tighten the capsule around the hip can help. Most recent studies on hip surgery focus on arthroscopy labral tears. Studies found that hip arthroscopy improved function and symptoms for many patients, even 10 years after surgery. However, revision rates and conversions to hip replacements varied. Factors like cartilage damage, existing OA, and older age were linked to worse outcomes.
Diagnosis & Clinical Testing
Screening Tests - Ruling a Diagnosis OUT
While clinical tests can help identify who doesn't have non-arthritic hip pain, these tests are less reliable at confirming who does. Meaning, these test have a high Sensitivity and are therefore good at ruling conditions OUT. But these same tests also have poor Specificity and are therefor poor at confirming or ruling conditions IN.
When these clinical tests are done, a negative test strongly suggests the condition does not exist. A positive test means nothing - it does not confirm nor negate the diagnosis or condition. These tests are looking for pain in the front groin, side of the hip, or all around the hip joint Remember SNOUT: Sensitivity rules diagnosis out
FADIR Test: The FADIR (Flexion, ADduction, Internal Rotation) test is used to diagnose hip impingement. The patient lies on their back while the clinician flexes the hip and knee, then adducts (moves inward) and internally rotates the hip. The clinician is measuring pain during this movement.
FABER Test: The FABER (Flexion, ABduction, External Rotation) test, also known as the Patrick's test, is used to identify hip joint or sacroiliac joint abnormalities. The patient lies on their back and the clinician places the leg in a figure-four position (ankle over opposite knee) and gently presses down on the knee while stabilizing the opposite hip. The clinician is measuring pain during this movement.
Screening Tests - Ruling a Diagnosis IN
These test have a high specificity. When these clinical tests are done, a positive test suggests the condition does exist. A negative test means nothing - it does not confirm nor negate the diagnosis or condition. These tests are looking for pain at the end range of internal and external rotation. Remember SPIN: Specificity rules a diagnosis IN
Ligamentum Teres Test: This test assesses the integrity of the ligamentum teres. The patient lies on their back, and the clinician moves the hip into flexion, abduction, and external rotation. A positive test, indicated by pain or apprehension, suggests a possible tear or injury to the ligamentum teres.
Abduction-Hyperextension-External Rotation Test: This test evaluates the stability of the anterior hip structures. The patient lies on their side or back, and the clinician moves the hip into abduction, hyperextension, and external rotation. Pain or a sense of instability suggests anterior hip instability.
Prone Instability Test: This test assesses lumbar spine instability, often used in the context of low back pain rather than hip pathology. The patient lies prone on an examination table with their hips at the edge and legs hanging off. The clinician applies downward pressure to the lumbar spine while the patient lifts their legs. Decreased pain with leg lifting indicates lumbar spine instability.
Prone Apprehension Relocation Test: This test evaluates posterior hip instability. The patient lies prone, and the clinician moves the hip into hyperextension and external rotation. Apprehension or pain indicates posterior instability. Reapplying pressure to the femoral head to relocate it can alleviate symptoms, confirming the diagnosis.
Hyperextension-External Rotation Test: This test assesses anterior hip instability. The patient lies supine, and the clinician moves the hip into hyperextension and external rotation. Pain or a sense of instability indicates anterior hip instability.
Physical Therapy Hip Motion & Strength Measurements
Hip Flexion and Rotation: Studies indicate that individuals with hip problems exhibit a reduced range of motion (ROM) in hip flexion, internal rotation (IR), and external rotation (ER) compared to those without symptoms.
Specifically, hip flexion is reduced by 13°, IR by 4°, and ER by 5° in patients with hip issues.
Hip Abduction and Flexion in Athletes: Male athletes with Femoroacetabular Impingement Syndrome (FAIS) demonstrate decreased hip flexion, abduction, and IR compared to asymptomatic athletes.
Cam Morphology and ROM: Individuals with cam morphology on MRI exhibit reduced IR and hip flexion compared to those without cam morphology. Adolescent athletes with decreased hip IR and flexion are more likely to develop degenerative changes on MRI after 5 years.
Hip Strength: Various studies have found that individuals with hip issues, including those with FAIS, have weaker hip muscles compared to asymptomatic individuals.
Physical Therapy Movement Testing
The Star Excursion Balance Test (SEBT) scores were correlated with hip pain and symptoms. This test is used to assess dynamic balance and postural control. The patient stands on one leg at the center of a grid with eight lines extending in different directions. They then reach as far as possible with the other leg along each line, maintaining balance. The test measures the distance reached and evaluates any deficits in balance and stability, which are often linked to hip or lower extremity issues.
Hop and Sit-to-Stand Tests: Soccer players with hip/groin pain had shorter hop distances and performed fewer one-leg sit-to-stands than those without pain.
Hop Test: This test evaluates lower limb strength, power, and stability. The patient performs a single-leg hop for distance, assessing the ability to generate force and maintain balance upon landing. Shorter hop distances can indicate hip or groin pain and functional limitations.
Sit-to-Stand Test: This test measures lower body strength and functional mobility. The patient sits in a chair and stands up and sits down as many times as possible within a set period or performs a specific number of repetitions. The test assesses the strength and endurance of the hip and leg muscles.
Single-Leg Squat Test: This test assesses neuromuscular control, strength, and hip stability. The patient performs a squat on one leg, observing the knee's alignment and hip stability. Poor control or increased pain during the test indicates potential hip dysfunction or weakness.
Step-Down Test: This test evaluates hip and knee control during a functional movement. The patient steps down from a platform or step and returns to the starting position. The test looks for hip and knee alignment, stability, and control. Poor performance can indicate neuromuscular deficits and increased hip pain.
Imaging
Imaging studies help rule out serious issues like cancer or fractures and provide information on bone and soft tissue structures.
The American College of Radiology recommends hip and pelvic X-rays first for hip pain.
Other imaging like MRIs can identify labral tears and other soft tissue issues.
CT scans can be used before surgery to assess bone structure.
Using these tools, doctors and therapists can better understand hip pain and decide on the best treatment options.
Physical Therapy Treatment for Hip Pain
Nonoperative interventions for patients with nonarthritic hip joint pain were first introduced in the 2014 guidelines. At that time, the recommendations were primarily based on expert opinion due to the lack of high-quality evidence. Since then, more research has been conducted, leading to the development of additional treatment categories and updated terminology.
Most studies focus on treating patients with nonarthritic hip pain suggest that physical therapy should be the first line of treatment. A multimodal intervention includes several treatments like:
Education: helps patients understand their condition and modify activities
Manual therapy: improves hip mobility by addressing soft tissue restrictions
Neuromuscular re-education: focuses on balance and coordination
Exercises: improve muscle flexibility, strength, and power. Exercises that provoke symptoms should be avoided. Specific exercises to strengthen specific hip muscles (iliopsoas, gluteus medius, gluteus maximus, internal and external rotators), trunk muscles (abdominals and paraspinals), and general lower body muscles (lunges, squats, step-ups) are recommended.
Movement pattern training: teaches patients how to move their lower body correctly during activities that cause them pain, like going down stairs, sitting at a desk, or cycling. A physical therapist observes how the patient moves during these activities to identify pain-inducing movements. For example, if someone’s hip moves too much inward during squatting or going downstairs, the therapist will have them try the same activity with a different movement pattern.
Recommendations for Clinicians
Use therapeutic exercises and activities to address joint mobility, muscle flexibility, and muscle strength deficits in patients with nonarthritic hip joint pain.
Provide patient education and counseling to help patients manage pain and modify activities that aggravate their nonarthritic hip joint pain.
A 12-week nonoperative treatment program that includes avoiding painful activities like squatting, leg crossing, pivoting, and sitting on the floor can be effective. About 55% of patients can perform daily activities normally after this treatment, while 45% may need surgery.
Education on activity modification is helpful for patients with FAIS. They should be advised to avoid positions and movements that cause pain, consistent with previous guidelines.
Studies on hip unloader braces show mixed results. Some patients reported discomfort from the brace. More research is needed to determine if bracing is beneficial for nonarthritic hip joint pain.
Joint and soft tissue mobilization procedures may be used to address pain or stiffness that impairs hip mobility.
Clinicians may use neuromuscular re-education to improve movement coordination in patients with nonarthritic hip joint pain.
Enseki, K. R., Bloom, N. J., Harris-Hayes, M., Cibulka, M. T., DiSantis, A., Di Stasi, S., Malloy, P., Clohisy, J. C., & Martin, R. L. (2023). Hip pain and movement dysfunction associated with nonarthritic hip joint pain: A revision. Clinical practice guidelines linked to the International Classification of Functioning, Disability, and Health from the Academy of Orthopaedic Physical Therapy and American Academy of Sports Physical Therapy of the American Physical Therapy Association. *Journal of Orthopaedic & Sports Physical Therapy, 53*(7), CPG1-CPG70. https://doi.org/10.2519/jospt.2023.0302