9.28 Plantaris Tendon Rupture

agk’s Library of Common Simple Emergencies

Presentation

The patient will come in limping, having suffered a whip-like sting in his calf while stepping off hard on his foot or charging the net during a game of tennis, or similar activity. He may have actually heard or felt a “snap” at the time of injury. The deep calf pain persists and may be accompanied by mild swelling and ecchymosis. Neurovascular function will be intact.

What to do:

• Rule out an Achilles tendon rupture. Test for strength in plantar flexion (can the patient walk on his toes?). Squeeze the Achilles tendon and palpate for a tender deformity that repre sents a torn segment. If pain does not allow active plantar flexion, squeeze the gastrocnemius muscle with the patient kneeling on a chair and look for the normal plantar flexion of the foot. This will be absent with a complete Achilles tendon tear. With any Achilles tendon tear, orthopedic consultation is necessary.
• When an Achilles tendon rupture has been ruled out, provide the patient with elastic support (e.g., ACE, TEDs stocking, Tibigrip) from foot to tibial tuberosity.
• Provide the patient with crutches for several days. Permit weight bearing only as comfort allows.
• Have the patient keep the leg elevated and at rest for the next 24-48 hours, initially applying cold packs, and after 24 hour alternately with heat every few hours.
• An analgesic such as codeine may be helpful initially and heel elevation should be provided for several weeks.

What not to do:

• Do not bother getting x rays of the area unless there is a suspected associated bony injury. This is a soft tissue injury that is not generally associated with fractures.

Discussion

The plantaris muscle is a pencil-sized structure tapering down to a fine tendon which runs beneath the gastrocnemius and soleus muscles to attach to the Achilles tendon or to the medial side of the tubercle of the calcaneus. The function of the muscle is of little importance and, with rupture of either the muscle or the tendon, the transient disability is due only to the pain of the torn fibers or swelling from the hemorrhage. Clinical differentiation from complete rupture of the Achilles tendon is sometimes difficult to make. Most instances of “tennis leg” are now felt to be due to partial tears of the medial belly of the gastrocnemius muscle or to ruptures of blood vessels within that muscle. The greater the initial pain and swelling, the longer one can expect the disability to last.

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