An Achilles tendon reconstruction may become necessary when there has been a rupture (complete tear) of the tendon which has either not healed or healed lengthened, rendering it dysfunctional or lacking sufficient integrity to allow the calf musculature to pull with normal power.
When pain and disability related to the degenerative disorder known as achilles tendinosis has failed non-operative attempts to bring symptoms under control, a reconstruction may also be required.
When an otherwise normal achilles tendon tears or ruptures during an activity such as sport or pushing forcefully off the extremity, a decision is usually made soon after the episode to manage the injury with or without an operation, but with careful attention to detail the outcome following this approach is usually excellent with an eventual return to normal activities. However, if the diagnosis is made late, or if poor management decisions are made during the first six weeks after the tear, the tendon may either not heal at all or perhaps heal in a lengthened state, resulting in permanent weakness. For the first six weeks after any rupture, whether or not an operation to repair the tendon acutely is performed, there typically needs to be a six week period of splintage of the ankle in an equinus (foot flexed down) position, with protected weight-bearing on the extremity.
After six weeks it is not technically possible to perform an end-to-end repair of a ruptured tendon due to retraction of the proximal (top) end of the tendon, the formation of adhesions between the muscle and its sheath and shrinkage of the muscle belly itself. A graft may then need to be used to “bridge” the defect in the tendon in order to restore continuity. This is commonly the adjacent tendon, known as the Flexor Hallucis Longus (FHL), the bender of the middle joint of the great toe. This has a strong muscle which helps to overcome the weakness caused by shrinkage of the calf!
Sometimes, with a long-standing/chronic tendon rupture, extensive scar tissue forms in the tendon defect, although this is elongated, and this can be shortened without the need for a graft of tendon transfer, in order restore tendon continuity.
Following either of these operations, there would need to be a six week post-operative period of ankle splintage and non-weight-bearing on the extremity. It can take some months to recover close to maximum strength.
The goal of this type of surgery is the removal of all severely degenerative tendon, in order to eliminate pain. Tendon continuity needs either to be protected or reconstituted.
In the case of insertional tendon disease, degenerative tendon can only be removed (debrided) by detaching some or occasionally all of the tendon from its normal insertion at the back of the heel. Detachment is also required to remove extra bone which has formed within the tendon at or near its anchor point. Additionally, when there is evidence of pressure between the tendon and the normal heel bone prominence in front of it (Haglund’s Syndrome), this may also need to be removed.
Detached healthy tendon is always reattached to the underlying healthy bone after “spur” removal, using buried anchors.
Sometimes, when all the insertional tendon is severely affected and needing to removed, an FHL tendon transfer is required to augment the reconstruction.
In the case of tendinosis affecting the mid-section of the tendon, above the level of the heel, affected degenerative tendon is excised, with an oversewing of the defect, but once again, on occasions, an FHL tendon transfer may be needed to bridge an extensive defect.
Post-operatively, management depends on how extensive the procedure has been. When more than 50% of the cross-sectional area of the tendon has been detached and reattached, or debrided, a six week period of non-weight-bearing may be required. When detachment or debridement has been minimal, many people are allowed to take full weight immediately. It can take over three months to fully recover.
As with all operations, the relative merits of an achilles tendon reconstruction need to be balanced against the relevant attendant risks and disadvantages.