Hip impingement syndromes
Doctors from Cambridge University Hospitals say that extra-articular hip impingement syndromes encompass a group of conditions that have previously been an unrecognised source of pain in the hip and on occasion been associated with intra-articular hip impingement as well.
Extra-articular hip impingement syndromes means problems caused from outside of the hip joint itself as opposed to intra-articular hip impingement syndromes which come from within the hip itself. Where it was once thought that hip impingment was caused by bone abnormalities limited to the ball and socket portion of the hip joint, doctors, including the Cambridge report cited below are finding that hip impingement can be caused by the pelvic bones as well.
The Cambridge doctors categorized these syndromes as:
- Ischiofemoral impingement: quadratus femoris muscle becomes compressed between the lesser trochanter portion of the thigh bone and the ischial tuberosity (the sit bones of the lower pelvis). We cover this problem in our article: Ischial tuberosity pain and ischiofemoral impingement: Here we describe Ischial tuberosity pain and ischiofemoral impingement. Focus will be on two types of problems. Impingement caused by instability and non or malunion of the fragment of the Ischial tuberosity caused by apophyseal (growth plate) avulsion fractures in young athletes.
- Subspine impingement: anatomical problems of the anterior inferior iliac spine (the wing of the upper iliac/pelvic bones) and the distal anterior femoral neck (the neck of the thigh bone) causing soft tissue entrapment of muscle and tendon.
- Iliopsoas impingement: friction between the iliopsoas muscle and the hip labrum, resulting in hip labrum breakdown. We cover issues in this article of the iliopsoas or psoas muscle as a cause of difficult to treat groin pain. Also see our article on surgery for hip labral tear.
- Deep gluteal syndrome: pain occurs in the buttock due to the entrapment of the sciatic nerve in the deep gluteal space. In our articles we cover a lot of information on the buttock pain and the pelvic, lower spine connection. See also the connection with Hamstring injuries.
- Pectineofoveal impingement: pain occurs when the medial synovial fold impinges against overlying soft tissue, primarily the zona orbicularis (the hip hip annular ligament).
The researchers concluded with a message to doctors that extra-articular hip impingement syndromes should be taken into consideration and should form a part of the differential diagnoses alongside intra-articular pathology including femoro-acetabular impingement particularly in the younger patient with a non-arthritic hip.1
Scans and MRIs for Subspine impingement
As described above, Subspine impingement involves problems of the anterior inferior iliac spine and the neck of the thigh bone. In looking at patients with Anterior Inferior Iliac Spine problems, doctors at the Walter Reed National Military Medical Center suggest that a high percentage of patients with Anterior Inferior Iliac Spine problems associated with subspinous impingement are, in fact, asymptomatic. That the current radiographic classification system should not be used exclusively for clinical decision making.2
But doctors keep looking at the Anterior Inferior Iliac Spine Anterior because as doctors report in the British Medical Journal, the “inconsistent bony morphology and the pull of the rectus femoris muscle putting it at risk for an avulsion fracture.”3
1 Nakano N, Yip G, Khanduja V. Current concepts in the diagnosis and management of extra-articular hip impingement syndromes. Int Orthop. 2017 Apr 11. doi: 10.1007/s00264-017-3431-4. [Pubmed]
2 Balazs GC, Williams BC, Knaus CM, Brooks DI, Dickens JF, McCabe MP, Anderson TD. Morphological Distribution of the Anterior Inferior Iliac Spine in Patients With and Without Hip Impingement: Reliability, Validity, and Relationship to the Intraoperative Assessment. Am J Sports Med. 2017 Apr;45(5):1117-1123. [Pubmed]
3. Sandilands SM, Raudenbush BL, Carreira DS, Cross BJ. Extra-articular hip impingement due to heterotopic ossification formation at the anterior inferior iliac spine following previous pelvic external fixation. BMJ Case Rep. 2016 Sep 16;2016. pii: bcr2015213610. [Pubmed]