Psoas strain/ bursitis

Findings

Groin pain with, or following, hill running, high knee drills or running on muddy ground when the foot has to be pulled out of the ground. Sometimes running bent over, as in field hockey. Passive hip flexion beyond 90 degrees produces groin pain and resisted hip flexion at 90 degrees is painful. There is tenderness to palpation at about two fingers’ breadth, lateral to the femoral artery at the groin. Psoas stretch is tight and painful. Straight leg sit-up, or leg raise may cause pain. A weak psoas may cause anterior knee pain or adductor tendonitis as psoas weakness reduces active hip flexion, thus encouraging a low knee, valgus movement, and it can present with atypical movement patterns when trying to run.

Cause

Inflammation of the psoas bursa. Weaknesses and strain of the psoas muscle with, occasionally, avulsion or enthesopathy, of the lesser trochanter.

Treatment

a)      Electrotherapeutic modalities to settle inflammation of the bursa, such as ultrasound and interferential

b)      Local injection of the bursa with cortisone

c)      Massage, stretching of the hip and isometric hip flexion at 90 degrees to control scar tissue

d)     Cross-training and rest from hip flexion, especially if there is an enthesitis or avulsion of the lesser trochanter

e)      Isometric hip flexion at 90 degrees, for strength

f)       High knee drills of the affected leg whilst standing on the other

g)      Achilles ladder. Concentrate on high knee section

Sports

      a)      This is often seen in runners, especially runners who carry their knees low and often into valgus, who then start speed drills of hill running, which requires a higher knee lift

b)      Field hockey and cross-country skiing can produce the problem in the unfit – one by a crouched running style, the other by an overload when the leg is swung forwards

The psoas weakness, which reduces hip flexion and therefore speed and acceleration, may go unnoticed, but it should be looked for in many knee, leg and ankle problems. Rehabilitation of this muscle may be the key to settling the other problems. The lesser trochanteric enthesis takes patience and time to settle. 

"Concise guide to sports injuries, 2^nd edition",Churchill Livingstone, Malcolm T.F. Read,  foreword by Bryan English