Abstract
This case report describes the evaluation, surgical intervention, and postoperative outcome of a 36-year-old male patient with chronic left hip pain following a rectus femoris injury which persisted despite conservative management and intra-articular steroid injection. Imaging revealed prominent ossification extending from the anterior inferior iliac spine at the proximal rectus femoris insertional, a femoral cam lesion, and tearing of the superior through anterior labrum, compatible with both subspine and femoroacetabular impingement. Subsequent arthroscopic femoroplasty, acetabuloplasty, labral repair, and excision of rectus femoris ossification provided lasting symptomatic relief. Identification of lesions resulting in subspine impingement is essential in the preoperative work up of patients with hip pain to ensure appropriate surgical management and optimize postoperative outcomes.
Keywords: Labral tear, Femoroacetabular impingement, Subspine impingement, Cam lesion, Pincer lesion, Rectus femoris avulsion
Introduction
Chronic hip pain can significantly impact an individual's quality of life. Understanding the underlying cause is crucial for appropriate management. Intra-articular causes of hip impingement, such as femoroacetabular impingement (FAI), as well as extra-articular causes, such as subspine impingment (SSI), are frequent causes of hip pain in prearthritic young individuals [[1], [2], [3]]. Femoroacetabular impingement (FAI) is a condition that involves abnormal contact between the femoral head and the acetabulum leading to damage of intrinsic joint structures, including the labrum and articular cartilage, resulting in pain and reduced hip function [4]. FAI can result from abnormality of the proximal femur (cam-type), or acetabulum (pincer-type). Cam-type impingement is caused by an osseous prominence along the junction of the femoral head and neck which results in abnormal contact with the acetabular rim, leading to chondral and labral injury, typically along the anterior superior acetabulum [5]. Pincer-type FAI is due to an acetabular abnormality resulting in over-coverage of the femoral head, either diffuse (e.g. coxa profunda, acetabular protrusion) or focal (e.g. acetabular retroversion, os acetabuli). This leads to abutment between the acetabular rim and proximal femur with subsequent chondral and labral injury at the site of the acetabular abnormality, most often also along the anterior superior acetabulum [5]. Subspine impingement is a form of extra-articular hip impingement resulting from an abnormally prominent anterior inferior iliac spine (AIIS) contacting the femoral neck often as a result of a prior avulsion injury at the rectus femoris origin [3,6]. SSI and FAI have similar clinical presentations; distinguishing between the 2 is critical for proper management and treatment with a definitive diagnosis requiring imaging [7,8]. Typical FAI surgical treatments include arthroscopic acetabuloplasty and/or femoroplasty, whereas subspine impingement requires additional arthroscopic subspine decompression or ossification excision [9,10]. The aim of this report is to highlight the importance of imaging in evaluation and surgical planning for prearthritic patients presenting with hip pain.
Case report
A 36-year-old male presented with a chief complaint of left hip pain that started approximately 8 years prior following a reported injury to his rectus femoris. Initially, the patient was treated conservatively, including physical therapy, which was effective. However, his left hip pain subsequently returned and progressively worsened, localized to the groin, back of hip, and quadratus lumborum muscle, resulting in difficulty with standing and activities of daily living. Physical examination revealed limited range of motion in the left hip compared to the right hip with normal and symmetric strength. Provocative flexion/internal rotation test for labral tear and scour test were positive. Log roll, FABER, Ober's, and straight leg raise tests were negative. A left hip intra-articular steroid injection was performed which provided significant pain relief (∼70%) for approximately 2 months before symptoms returned to preinjection levels.
Initial radiographs demonstrated prominent inferolaterally directed heterotopic ossification adjacent to the left anterior inferior iliac spine along the course of the proximal rectus femoris tendon as well as an osseous prominence at the femoral head-neck junction with an elevated alpha angle, compatible with a cam deformity (Fig. 1). Subsequent MRI revealed a tear of the superior through anterior labrum (Fig. 2) and confirmed the location of ossification within the proximal rectus femoris tendon (Fig. 2). The MRI also confirmed the presence of a cam lesion (Fig. 2).
Fig. 1.
Dunn view radiograph (A) demonstrates an osseous prominence at the femoral head neck junction compatible with cam lesion (white bracket) as well as osseous proliferation (white arrow) and separate focus of heterotopic ossification (yellow arrow) extending from the anterior inferior iliac spine. AP radiograph (B) demonstrates slightly elevated lateral center edge angle of 44 degrees. The cam lesion (white bracket) and osseous proliferation (white arrow) are again seen.
Fig. 2.
Coronal T1 MRI sequence (A) confirms location of the osseous proliferation extending along the rectus femoris insertion at the anterior inferior iliac spine (white arrow). Coronal and sagittal T2 FS MRI sequences (B,C) demonstrates tearing of the superior through anterior labrum (white arrowhead). Axial oblique T1 MRI sequence (D) confirms osseous prominence at the femoral head neck junction compatible with cam lesion (white brackets).
Subsequent arthroscopic surgery demonstrated labral tear spanning 9 to 1 o'clock, acetabulofemoral chondrosis, an acetabular pincer lesion, a cam lesion at the femoral head-neck junction, and a large focus of ossification within the proximal rectus femoris tendon. The labral tear was repaired, acetabuloplasty and femoroplasty of the pincer and cam lesions, respectively, was performed, and the rectus femoris ossification was excised.
A postoperative radiograph demonstrates excision of the rectus femoris ossification as well as postsurgical changes of femoroplasty and acetabuloplasty (Fig. 3). On postoperative follow up examination, there was improved range of motion of the left hip with resolution of previously demonstrated positive flexion/internal rotation and scour tests.
Fig. 3.
Dunn view radiograph following femoroplasty, acetabuloplasty, and excision of anterior inferior iliac spine osseous proliferation with resolution of cam lesion (white bracket) and anterior inferior iliac spine osseous proliferation (white arrow). The smaller focus of heterotopic ossification is still present (yellow arrow).
Discussion
Chronic hip pain can significantly impair quality of life, necessitating accurate diagnosis for optimal management. Femoroacetabular impingement (FAI) and subspine impingement (SSI) are recognized causes of hip pain in younger patients, often requiring surgical intervention for symptomatic relief [11]. This case report outlines the evaluation, surgical intervention, and postoperative outcome of a 36-year-old male with chronic left hip pain following a rectus femoris injury. The importance of distinguishing between FAI and SSI through imaging is highlighted to guide appropriate surgical management and optimize postoperative outcomes.
The initial radiographs demonstrated 2 key findings—prominent inferolaterally directed ossification adjacent to the left AIIS, suggestive of subspine impingement, and an osseous prominence at the femoral head-neck junction with an elevated alpha angle and a borderline elevated lateral center-edge angle, characteristic of cam-type FAI with possible component of pincer-type FAI. Subsequent MRI confirmed the cam deformity and ossification within the proximal rectus femoris tendon as well as demonstrating a tear of the superior through anterior labrum. These imaging findings collectively aided in the diagnosis of both intra-articular and extra-articular impingement, guiding the subsequent surgical approach to address both etiologies of impingement.
Identification of lesions causing impingement is crucial in the preoperative workup of patients with hip pain. FAI and SSI may present with overlapping symptoms, making it imperative to differentiate between the 2 for appropriate surgical planning [11]. Despite their similar clinical presentations, FAI and SSI surgeries are inherently different. The approach for FAI involves femoroplasty and acetabuloplasty whereas SSI requires additional decompression with excision of the abnormal ossification [12]. It is noteworthy that the patient in this case exhibited both subspine impingement and femoroacetabular impingement simultaneously. The coexistence of these pathologies underscores the importance of distinguishing between the 2, as failure to identify SSI in patients with FAI may result in suboptimal postsurgical outcomes and the potential need for revision surgery [13].
Patient consent
Informed written consent was obtained from the patient for publication of this case report and all imaging studies. Consent form on record.
CRediT authorship contribution statement
Alex Ha: Investigation, Resources, Writing – original draft. Daria Motamedi: Conceptualization, Supervision, Writing – review & editing. Kevin Sweetwood: Conceptualization, Supervision, Writing – review & editing.
Footnotes
Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
References
- 1.Thomas GE, Palmer AJ, Andrade AJ, Pollard TC, Fary C, Singh PJ, et al. Diagnosis and management of femoroacetabular impingement. Br J Gen Pract. 2013;63(612):e513–e515. doi: 10.3399/bjgp13×669392. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 2.Cheatham SW. Extra-articular hip impingement: a narrative review of the literature. J Can Chiropr Assoc. 2016;60(1):47–56. [PMC free article] [PubMed] [Google Scholar]
- 3.Zhang C, Li L, Forster BB, Kopec JA, Ratzlaff C, Halai L, et al. Femoroacetabular impingement and osteoarthritis of the hip. Can Fam Physician. 2015;61(12):1055–1060. [PMC free article] [PubMed] [Google Scholar]
- 4.Bedi A, Dolan M, Leunig M, Kelly BT. Static and dynamic mechanical causes of hip pain. Arthroscopy. 2011;27(2):235–251. doi: 10.1016/j.arthro.2010.07.022. [DOI] [PubMed] [Google Scholar]
- 5.Macfarlane RJ, Haddad FS. The diagnosis and management of femoro-acetabular impingement. Ann R Coll Surg Engl. 2010;92(5):363–367. doi: 10.1308/003588410×12699663903791. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.Hetsroni I, Larson CM, Dela Torre K, Zbeda RM, Magennis E, Kelly BT. Anterior inferior iliac spine deformity as an extra-articular source for hip impingement: a series of 10 patients treated with arthroscopic decompression. Arthroscopy. 2012;28(11):1644–1653. doi: 10.1016/j.arthro.2012.05.882. [DOI] [PubMed] [Google Scholar]
- 7.Samim M, Walter W, Gyftopoulos S, Poultsides L, Youm T. MRI assessment of subspine impingement: features beyond the anterior inferior iliac spine morphology. Radiology. 2019;293(2):412–421. doi: 10.1148/radiol.2019190581. [DOI] [PubMed] [Google Scholar]
- 8.Nakano N, Lisenda L, Khanduja V. Arthroscopic excision of heterotopic ossification in the rectus femoris muscle causing extra-articular anterior hip impingement. SICOT J. 2018;4:41. doi: 10.1051/sicotj/2018036. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 9.Poultsides L.A., Nwachukwu B.U., Kelly B.T. In: Hip arthroscopy and hip joint preservation surgery. Nho S.J., Bedi A., Salata M.J., Mather R.C. III, Kelly B.T., editors. Springer; Cham: 2022. Subspine impingement and surgical technique. [DOI] [Google Scholar]
- 10.Nasser R, Domb B. Hip arthroscopy for femoroacetabular impingement. EFORT Open Rev. 2018;3(4):121–129. doi: 10.1302/2058-5241.3.170041. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 11.Aguilera-Bohórquez B, Ramirez S, Cantor E. Functional results of arthroscopic treatment in patients with femoroacetabular and subspine impingement diagnosed with a 3-dimensional dynamic study. Arthrosc Sports Med Rehabil. 2019;2(1):e39–e45. doi: 10.1016/j.asmr.2019.10.007. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 12.Xu LY, Chen KM, Peng JP, Zhu JF, Shen C, Chen XD. Outcomes after management of subspine and femoroacetabular impingement using a direct anterior mini-open approach. Orthop J Sports Med. 2021;9(12) doi: 10.1177/23259671211055723. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Sogbein OA, Shah A, Kay J, Memon M, Simunovic N, Belzille EL, et al. Predictors of outcomes after hip arthroscopic surgery for femoroacetabular impingement: a systematic review. Orthop J Sports Med. 2019;7(6) doi: 10.1177/2325967119848982. [DOI] [PMC free article] [PubMed] [Google Scholar]