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Physio Penrith Hip Subspine Impingement Treatment

Treatment of Hip Subspine Impingement at Sydney Muscle & Joint Physio Penrith

What is a hip subspine impingement?

Hip subspine impingement is a term used to denote the collision that may occur between an enlarged or malorientated anterior inferior iliac spine (AIIS) and the distal anterior femoral neck in straight flexion of the hip. Involvement of soft-tissue structures, such as the direct head of the rectus femoris and the iliocapsularis muscles, or the anterior hip capsule, in the impingement process has also been postulated. 

Morphological changes (changes in the shape) of the AIIS may develop from excessive and recurrent tension of the iliofemoral ligament and the anterior hip capsule during repetitive forced extension and external rotation of the hip, commonly observed in running and fields sports, particularly during adolescent years.

What are the symptoms of a hip subspine impingement?

The clinical presentation of hip subspine impingement overlaps with that of femoroacetabular impingement, in part because the two more often than not co-exist. Hip subspine impingement will present with anterior (front) hip or groin pain, and less commonly buttock pain. Pain is increased with hip flexion, adduction and internal rotation. Range of motion testing may reveal valgus and anteverted hips and decreased hip adduction and external rotation- causing an impingement between a normally shaped AIIS and the greater trochanter or the anteroinferior femoral neck.

Unique signs and symptoms suggestive of subspine impingement include a ‘grinding’ sensation of the hip, pain with kicking/sprinting activities, local tenderness on palpation of the AIIS, groin pain with straight flexion beyond 90 and only partial relief after an intra-articular test injection.

How do you diagnose a hip subspine impingement?

The most consistent investigation for subspine impingement is plain radiographs (anteroposterior of pelvis and false-profile of hip) and a CT scan if further analysis is required. On physical examination the FADIR test will result in pain and limitation of internal rotation and adduction with the hip flexed to 90°. This manouevre also commonly results in anterior groin pain. On further questioning individuals may report activity related groin pain with post activity hip stiffness in conjunction with reduction in hip flexion, internal rotation and adduction and presence a positive impingement test are the characteristic clinical findings.

What is guideline-based treatment of hip subspine impingement?

Typically, a trial of conservative management, including relative rest, anti-inflammatory medications, and pain medications as necessary, combined with a focused physiotherapy protocol for 10–12 weeks is recommended initially.

New research is coming out and shedding fresh light on a muscle called iliocapsularis also referred as the iliacus minor or ilioinfratrochantericus, lies deep in the body relative to the rectus femoris muscle. The iliocapsularis muscle has an attachment to the anteromedial capsule of the hip. Among the muscles attaching to the hip capsule such as the gluteus minimus, obturator externus, obturator internus and gemellus muscles, the iliocapsularis muscle has the largest capsular contribution. Due to this contribution, the iliocapsularis muscle has a direct anteromedial capsular attachment. Hereby contraction of the iliocapsularis muscle pulls the capsule with the zona orbicularis in a superior and medial direction; this motion might tighten these structures and help stabilise the femoral head within dysplastic acetabulum. As the importance of the zona orbicularis and anterior hip capsule with regard to hip stability have already been confirmed, it is highly possible that the iliocapsularis muscle contributes to hip stability through the capsule along with the zona orbicularis.

As a result, the physiotherapists at Sydney Muscle & Joint Clinic treat those individuals with and without normal hip anatomy (ruling in/out FAI or subspine impingement), by increasing the strength of the iliocapsularis (as well as iliacus and iliopsoas muscles) in order to provide increased hip stability during hip flexion and extension movements. This is recent evidence-based practice and something our physios will focus on for patients with hip pain, stiffness, reduced range of motion and a diagnsos of subspine impingement.

If long-term conservative treatment fails studies suggest arthroscopic resection of an impinging AIIS, also termed ‘spinoplasty’. The diagnosis of subspine impingement is confirmed arthroscopically by the presence of anterior focal synovitis and labral bruising in the area of the AIIS, as well as the presence of bony accumulation, representing the distal extension of the AIIS, on the acetabular rim. The surgical technique is predicated by the anatomy of the AIIS.

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