Clinical History: 18-year-old track athlete with left thigh pain. Fat-suppressed T2-weighted axial (1a) and STIR coronal (1b) images are provided. What are the findings? What is your diagnosis?
Adductor Insertion Avulsion Syndrome (Thigh Splints)
Hip and thigh pain is a common complaint among athletes with a hip injury rate of 53.1 per 100,000 athletic exposures in National Collegiate Athletic Association athletes.1,2 The etiologies include intra-articular or extra-articular pathologies arising in the bones or soft tissues of the hip, thigh, or groin.3,4
Adductor insertion avulsion syndrome, or “thigh splints”, is a painful traction-related stress injury of the proximal to mid femur at the adductor insertions along the posteromedial femoral diaphysis (3). It is an important and sometimes overlooked cause of hip pain1, 5 and has been described in adults6,7and children.7,8
This web clinic reviews adductor insertion avulsion syndrome (thigh splints), and the differential diagnosis for hip/thigh pain in the athlete.
Thigh splints typically present with activity-related groin or posteromedial proximal thigh pain relieved with rest.4
Physical examination findings include increased adductor tone, tenderness over the adductor muscles and severe pain with active resistance to hip adduction and external rotation.3
MRI findings include a thin rim of hyperintense water-sensitive sequence signal (T2 and STIR) along the medial cortex of the proximal to mid femoral shaft consistent with periostitis.3 Mild adjacent soft tissue edema may also be present. In advanced cases, cortical and bone marrow edema may be present consistent with developing stress fracture (4a, 4b, 4c).
Given the insertion sites of the adductor muscles, thigh splints are commonly at the inferior edge of the field of view for a typical hip or pelvis MRI (5a and 5b).
Initial radiographs may be normal or show fluffy immature periostitis (6a). Over time periostitis will mature and become smooth (6b).
Bone scintigraphy, if performed, demonstrates a linear band of increased radiotracer uptake along the posteromedial femur on delayed images.6
The differential diagnosis for thigh splints is broad and can be broken down into intra-articular hip pathology and extra-articular hip, thigh, and groin pathology.
Intra-articular etiologies of hip and thigh pain include osseous and soft tissue pathologies. Femoral neck stress fracture (7), osteochondral injuries (8) and either benign (9) or malignant osseous tumors are examples of intraarticular osseous pathologies. Acetabular labrum tear (10) and synovial-based processes (11) are examples of intraarticular soft tissue pathologies.
Extraarticular etiologies of hip and thigh pain include osseous and soft tissue pathologies. Apophyseal injury (12), benign (13) or malignant osseous tumor (14) and osteomyelitis are examples of extraarticular osseous pathologies. Athletic pubalgia (15), muscle strain (16), muscle contusion (17) and benign or malignant soft tissue tumors are examples of extraarticular soft tissue pathologies.
Once a diagnosis of thigh splints has been determined, the athlete should be managed conservatively with rest and gradual return to physical activity.4
Adductor insertion avulsion syndrome, or “thigh splints”, should be considered in the differential diagnosis for an athlete or active individual with groin, hip or proximal medial thigh pain. Given the wide range of both intraarticular and extraarticular pathology resulting in groin, hip or thigh pain, MR imaging is commonly used to make the diagnosis of thigh splints. Due to the location of the injury, close attention to the inferior edge of the field of view for a typical hip or pelvis MRI is often necessary to make the diagnosis.
- Bojicic KM, Meyer NB, Yablon CM, Brigido MK, Gaetke-Udager K. Hip Pain: Imaging of intra-articular and extra-articular causes. Clin Sports Med. 2021; 713 (40). ↩
- Cruz CA, Kerbel Y, Smith CM, Prodromo J, Trojan JD, Mulcahey MK. A sport-specific analysis of the epidemiology of hip injuries in National Collegiate Athletic Association athletes from 2009 to 2014. Arthroscopy. 2019; 2724 (35). ↩
- Anderson MW, Kaplan PA, Dussault RG. Adductor insertion avulsion syndrome (thigh splints): Spectum of MR imaging features. AJR. 2001; 673 (177). ↩
- Hegazi TM, Belair JA, McCarthy EF, Roedl JB, Morrison WB. Sports injuries about the hip: what the radiologist should know. Radiographics. 2016; 1717 (36). ↩
- Pauchet A, Falticeanu A, Lebecque O. Adductor insertion avulsion syndrome with proximal femoral shaft stress fracture: not only found in young athletes. J of the Belgian Society of Radiology. 2020; 1 (104). ↩
- Charkes ND, Siddhivam N, Schneck CD. Bone scanning in the adductor insertion avulsion syndrome. J Nucl Med. 1987; 1835 (28). ↩
- Tshering-Vogel D, Waldherr C, Schindera ST, Steinbach LS, Stauffer E, Anderson SE. Adductor insertion avulsion syndrome, “thigh splints”: relevance of radiological follow-up. Skeletal Radiol. 2005; 355 (34). ↩
- Anderson SE, Johnston JO, O’Donnell R, Steinbach LS. MR imaging of sports-related pseudotumor in children: mid femoral diaphyseal periostitis at insertion site of adductor musculature. AJR. 2001; 1227 (176). ↩