(possibly should be renamed ‘Pubic stress injury’)
The pathophysiology in OP is contentious. Theories include:
- stress reaction of the pubic body/symphysis 2º to shear forces across the symphysis pubis
- an enthesopathy from above (rectus/conjoint tendon) &/or below (adductors) that spreads to the subchondral bone
- imbalance or loss of synergy between the abdominals and adductor muscles.
OP is poorly understood and treatment at present is at best empirical. OP often presents late and diagnosis is often delayed. Other pathologies (hernia, adductor tendinopathy etc) may coexist. There is potential for secondary pubic instability.
X-ray: There may be characteristic widening of the cleft & erosive changes in one or both margins (chronic stage → moth eaten appearance along margins pubic symphysis). Flamingo views are performed (>2mm movement constitutes pelvic instability). The delay in ossification of the adolescent SP (which is fully ossified by age 22-26 years) can cause much confusion in diagnosis.
Bone Scan: May get ↑ uptake in early stages (but this is not diagnostic as other conditions can have this finding)
CT: May show cystic changes and peri-symphysis erosions.
MRI: Gold standard. Bone marrow oedema is present in the body of pubis which is said to represent a bony stress response. Not as sensitive for bony architecture changes. Asymptomatic athletes may also show this appearance.
Younger athletes may show bone oedema on MRI, whereas more experienced athletes will have a moth eaten x-ray or cystic changes in the bone.
Signs include a positive squeeze test (isometric hip adduction at 0, 20, 40, & 60º of hip flexion) & tenderness over the pubic tubercles/symphysis. Pubic symphysis stress tests include single leg squatting, hopping, passive hip extension (the “cross-over sign” is where pain is reproduced contralateral to the test leg and is considered a poor prognostic sign), and passive hip abduction. There may be restricted hip ROM. Using a BP cuff may demonstrate a squeeze <100mmHg.
To grade severity:
- pain on passive abduction
- pain/weakness with resisted adduction
- pain on squeeze test
- pain on resisted hip flexion
- adductor muscle guarding on passive abduction/ER
- pain on resisted flexion/adduction in Thomas test position
There is pain emanating from the area of the symphysis pubis into the area of the lower rectus abdominis, the upper adductors and the perineum. It is usually insidious, and may be unilateral or bilateral. It is aggravated by exercise especially twisting & kicking. NSAIDs decrease symptoms incompletely. A short rest can help but pain returns when return to activity. There is a history of progressive deterioration.
Early accurate diagnosis should be followed by prompt removal of athlete from activities that cause pain which usually means exclusion from group training and competition. Rest potentially for 6-8 weeks to settle bony irritation. If the athlete has pain with ADL’s (e.g. coughing, sitting, getting in or out of a car) then should limit cross training and remove aggravating activities. To check for improvement perform the Thomas test +/- resisted adduction contraction and look for the cross-over sign. The squeeze test may be performed to monitor for an improvement in strength. Cross training should be undertaken (swimming, cycling and rowing). When pain free with ADL’s add in straight line running.
Conservative treatment includes spinal mobilization, neural stretches and massage to release adductor abdominal & psoas muscle groups (although muscle length should be regained without stressing the symphysis pubis). There should be aggressive abdominal strengthening (TA and multifidus) and pre-contraction of TA is considered essential. More experienced athletes with instability features will need to work on pelvic floor strengthening. As continue to improve, can add in progressive agility work (e.g. weaving through witches hats, progressing to unanticipated commands to change direction) and adductor strength.
Grade treatment by severity signs & response of these signs to a bout of exercise (e.g. an absent squeeze prior activity, which presents following activity probably means that the athlete is doing too much). This can lead to return to sport in 6-9 months.
Dextrose prolotherapy and IV bisphosphonate therapy has been advocated with some promising results. Long term studies are needed. Surgery has a limited role. Various procedures include debridement/curettage of the symphyseal cleft, bilateral partial adductor tenotomy, bilateral tenotomy of the conjoint tendons and wedge resection of the symphysis pubis or fusion of it.