Fig. 1 Flexor hallucis longus tendon transfer through traditional two-tunnel technique.Reprinted from Richardson EG (ed): OKU: Foot and Ankle 3. Rosemont, Ill., American Academy of Orthopaedic Surgeons, 2008, page 9.

AAOS Now

Published 10/1/2013
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Mary Ann Porucznik

When Is Grafting for Achilles Tendinosis Needed?

Tendon transfer can be helpful

“Surgical treatment of insertional Achilles tendinosis is indicated after more conservative measures—including NSAID medications, stretching and eccentric strength training, activity restriction, immobilization, and even extra-corporeal shock wave treatments—have proven ineffective,” John T. Campbell, MD, told members of the American Orthopaedic Foot & Ankle Society (AOFAS) during their 2013 Annual Meeting.

Dr. Campbell pointed out that the mainstay of surgical treatment includes resection of diseased tendon, removal of insertional spurs and the posterior Haglund’s process, and retrocalcaneal bursectomy. “Biomechanical data support tendon reattachment to the calcaneus if more than half of the insertional area is released during the débridement,” he said, adding that clinical results are excellent, with patient satisfaction rates ranging from 74 percent to 96 percent.

In some cases, however, augmentation of the Achilles insertion may be necessary. The degree of tendon degeneration, noted Dr. Campbell, may compromise the tissue left for reattachment, raising concerns over its healing capacity, durability, and ultimate strength. A literature review finds general consensus for augmentation if more than 50 percent of the Achilles tendon is torn or debrided away. Tendon augmentation may also offer better outcomes in older patients and may provide improved plantar flexion strength in obese patients, or those who work as laborers.”

FHL tendon transfer
According to Dr. Campbell, in the treatment of insertional tendinosis, flexor hallucis longus (FHL) transfer offers the following advantages compared to other potential donor tendons:

  • a dynamic in-phase transfer with an appropriate axis of pull
  • good relative strength
  • anatomic proximity
  • a hypothetical improvement in local vascularity to the Achilles region

He described the surgical technique, beginning with either a longitudinal posterior incision augmented by a second medial arch incision for tendon harvest at the knot of Henry or the use of a single longitudinal posterior incision for both harvesting and transferring the FHL. Dr. Campbell noted that the two-incision technique only adds 3 cm of additional tendon length and may risk injury to the medial plantar nerve, thus supporting the use of a single posterior incision.

After performing débridement of the Achilles and a posterior calcaneal exostectomy, Dr. Campbell harvests the FHL through the posterior incision (Fig. 1). He uses an osseous tunnel to transfer the FHL into the calcaneus and prefers to use an interference screw to secure it in place. After an initial 4-week immobilization period with weight-bearing restrictions, progressive rehabilitation focuses on strength and proprioception retraining, gait mechanics, and conditioning.

“Most patients achieve maximal improvement after 8 to 12 months,” said Dr. Campbell, who noted that literature reports indicated both significant pain relief and good functional recovery.

After surgery, compared to the normal limb, a plantar flexion torque deficit of 7 percent to as much as 25 percent has been reported, but this does not take into account any preoperative deficits and Dr. Campbell noted that such comparisons are lacking.

“I would give use of the FHL tendon to augment insertional Achilles tendon débridement a Grade B (fair level of evidence) recommendation, based on my review of the literature, although the exact indications remain to be defined,” said Dr. Campbell. “No direct clinical comparisons between single- and double-incision techniques are available, and retrospective Level IV studies of each method suggest equivalent outcomes between the two.”

Complications
Residual weakness, wound complications, pain, limping, nerve injury, and claw hallux deformity are among the complications that have been described after FHL transfer. In addition, said Dr. Campbell, “studies have shown that decreased pedobarographic pressure under the hallux and weakness of the hallux interphalangeal joint are common, but result in no clinical problem for most patients.”

Disclosure information: Dr. Campbell—OrthoHelix; Synthes; Arthrex, Inc.; Foot & Ankle International; Maryland Orthopaedic Association.

John T. Campbell, MD, is a surgeon at The Institute for Foot and Ankle Reconstruction at Mercy Medical Center, Baltimore; he can be reached at jcampbell@mdmercy.com

Bottom Line

  • If conservative treatment of insertional Achilles tendinosis is ineffective, surgical treatment may be indicated.
  • Depending on the degree of tendon degeneration, augmentation may be necessary.
  • A flexor hallucis longus transfer is one option, which provides both good relative strength and anatomic proximity.
  • Patient satisfaction rates are high, although complications include residual weakness, wound complications, pain, limping, nerve injury, and claw hallux deformity.