Extra-articular impingement of the hip
Hip impingement can be delineated into either intra or extra-articular contact between two anatomical structures involving the femoroacetabular joint. Extra-articular impingement is associated with the symptomatic impedance in the hip region of structures not morphologically associated with traditional femoroacetabular impingement (FAI). It is classified into either psoas, subspine, ischiofemoral (IFI) or greater trochanteric –pelvic impingement (GTPI). Previous studies have indicated that this form of impingement may only occur 4% of the time, and diagnosis is often muddled as it may co-exist with FAI. The authors of the present article chose to focus on the etiology and treatment of IFI and GTPI according to the most currently available literature.
IFI occurs when the quadratus femoris muscle is pinched between the lesser tuberosity and the ischial tuberosity, resulting in posterior hip and groin pain. Occurring more frequently in women, pain is often experienced insidiously in positions of adduction and external rotation. There are no validated clinical tests, however provocation can usually occur with extension, external rotation and adduction. Imaging studies have shown that both MRI and dynamic ultrasound can be effective tools to confirm the presence of IFI. Guided injections or surgical resection of the lesser trochanter should only be considered once traditional treatment approaches have failed. Treatment should focus on activity modification and strengthening of the abductors, internal rotators and quadratus femoris of the hip while stretching external rotators and adductors.
GTPI is typically associated with Perthes disease and involves the contact between the greater trochanter and ilium. Pain is often described in the groin and lateral aspect of the hip during abduction and extension. On physical examination the “gear-stick” sign can help confirm its presence: when the hip is taken to its bony end range then passively flexed and further abducted, the greater trochanter is enabled to move posteriorly and avoid the ilium. Plain radiographs are used to confirm the bony abnormalities of the proximal femur. From a medical perspective, trochanteric advancement is typically used to correct any bony abnormalities.
The current article investigates two variants of extra-articular hip impingement from a medical perspective. Overall, it was elucidated that when considering IFI initial treatment should be non-operative however treatment of GTPI more commonly begins with surgery.
> From: Beckmann et al., Oper Tech Sports Med 23 (2016) 184-189. All rights reserved to Elsevier Ltd. Click here for the Pubmed summary.