Achilles tendon is formed by the confluence of the Gastrocnemiusand Soleus@15cm above the calcaneous.
Hypovascular zone of the Achilles is 3-6cm proximal to its calcaneal insertion. (Stein V, Acta Orthop Scan 2000;71:60). Blood supply: vessels in the musculotendinous junction, surrounding mesotenal connective tissue and the calcaneal osseous insertion.
Sural nerve is most at risk during surgical approach. It crosses near the midline at the level of the musculotendinous junction of the achilles (@9.8 cm from the calcaneus) before descending to its more lateral location distally. At the level of insertion of the Achilles into the calcaneus, the sural nerve is 18.8 mm from the lateral border of the Achilles tendon. (Webb J, Foot ankle Int 2000;21:475)
Tensile forces = 1,400 to 2,600 N with walking, 3,100 to 5,330 N during running. 6-8 times body weight.
Achilles Tendonitis Clinical Evaluation
Pain and swelling in the Achilles tendon, generally no hx of trauma. Often associated with increase in training intensity, interval training, change from soft surface to hard surface training, worn-out footwear.
Evaluate for heel alignment and forefoot position (functional overpronation is caused by heel varus or forefoot supination)
Thompson's test is negative.
Achilles Tendonitis Xray
Plain films usually normal, may have prominent superior tuberosity of the os calcis on the lateral view, or calcifications in the Achilles tendon. Evaluate for Haglunds deformity.
MRI typical shows fusiform swelling and enlargement of the Achilles tendon proximal to its insertion. Paratendinitis, (ie, inflammation of the paratenon), appears as edema around the tendon without obvious tendon involvement. May be usefull preoperatively to identify regions of intratendinous degeneration in recalcitrant cases.
Achilles Tendonitis Classification/Treatment
Stage I = tendon normal, inflammatory changes in the peritendinous tissue (peritendinitis). Pain after prolonged running which dereases when running is stopped.
Stage II = degenerative and inflammatory changes in the tendon (tendinosis). Pain present at start of running and worsens with activity.
Stage III = Stage II with visible disruptions in the tendon. Unable to run, may have rest apin.
Initial treatment= activity modification, eccentric calf stretching and physical therapy with eccentric strengthening, plyometrics and gradual activity return. (Shalabi A, AJSM 2004;32;1286), (Clement DB, AJSM, 1984;12:179): +/-heel lifts (1/4-3/8in), NSAIDs, walking boot, orthotic to correct excessive pronation, ultrasound. Achilles tendonitis braces may be beneficial.
If nonsurgical rx fails=Debridement of intratendinous debris +/- excision of retrocalcaneal burse, +/- ostectomy of superior angle of os calcis, +/- turn-down gastroc fascial flap. Medial longitudinal incision. Involved areas are not only visualized as yellowish, amorphous segments, but palpable as more firm areas than the surrounding normal tendon. Local tendon grafts (FHL) can be used in severe cases where a large area needs debridment. (Paavola M, AJSM 2000;28:77). Consider complete tendon detachment, V-Y lengthening proximal to musculotendinous junction and reattachment with suture anchors if >50% of tendon is diseased (Wagner E, Foot Ankle Int 2006;27:677).
If paratendinitis is the diagnosis, debridement or excision of the paratenon can provide relief and a return to function
Steroid injections are associated with rupture and are contraindicated (Kleinman M, JBJS 1983;65A:1345)