Please help! Our son just came home from football practice on crutches. He has a lump behind the knee and can’t bend or straighten the leg all the way. The coach told him to ice it and just rest. We’re wondering if he needs to go to the emergency department now. Is this something that can wait until morning when the clinic is open and his regular doctor is available?

Conservative care with rest, elevation, ice, and antiinflammatory medication is the standard first-line treatment for muscular problems like this one. It does not sound like there is an undisplaced fracture since you didn’t mention any open wounds or bone sticking out of the skin. The suspicion of a bone fracture might be grounds for a visit to the emergency department.

If the lump you described does not go down (or go away) with conservative care, there may be more going on than just some swelling in response to an injury. An MRI may be needed to identify the tendon or muscle involved and to show the extent of the damage. Full ruptures or tears can be treated conservatively. Physical therapy to help restore motion, strength, and function is usually advised.

Failure to respond to conservative care may point to the need for surgery. But for right now, your decision is a short-term, immediate one. Waiting overnight is usually not a problem. Watch for increasing swelling that might suggest bleeding. When in doubt, it is always a good idea to seek medical care sooner than later.