Mr WF is a 51 year old gentleman who presented three weeks following a spontaneous rupture to the extensor hallucis longus tendon of his left foot at the level of the tarsometatarsal joint. He described spontaneous pain and a 'popping sensation' on the dorsum of his foot. He had lost all dorsiflexion to his left great toe and he felt he was tripping over the toe as he walked.
Clinically, he had bruising and swelling on the dorsum of his left foot. He walked with a 'toe drop' and no dorsiflexion to his left great toe. He had 1/5 power to left great toe dorsiflexion at the first metatarsophalangeal joint, but extensor hallucis longus and tibialis anterior were both intact and functioning at 5/5 power.
Interestingly, an initial ultrasound had reported that the extensor hallucis longus tednon was intact but this clearly did not match his clinical findings. An urgent MRI scan was obtained which demonstrated complete rupture of the extensor hallucis longus tendon with 3cm of retraction.
Mr WF was a high functioning gentleman and did not tolerate the weakness in his great toe, so there was not a role for non-operative treatment in this case. Surgical options were therefore discussed. The joint sacrificing procedure of a first metatarsophalangeal joint fusion was discussed, although Mr WF was concerned about the limited range of motion following a fusion procedure, as well the possibility of transfer arthritis to the interphalangeal joint later in life given his relatively young age.
We therefore discussed the option of joint salvage procedures. This would either be an attempt at direct repair or, if unable to be repaired, a tendon graft using an ipsilateral hamstring tendon graft, most likely the gracilis tendon given its similar size and shape to extensor hallucis longus.
Mr WF elected to proceed with an attempted repair and grafting. Intra-operatively, it was noted that there was a 5cm gap between the tendon edges which was irrepairable so the decision was made to proceed with a hamstring graft. The gracilis tendon was harvested at the knee and carefully transplanted to the ruptured ends of the extensor hallucis longus tendon on the dorsum of the foot.
Mr WF was placed in a backslab for two weeks following the surgery, then commenced partially weight bearing in a CAM boot until six weeks post operatively. At that stage, he transitioned to a normal shoe with a carbon fibre plate and started gentle range of motion exercises of his great toe.
Three months following surgery, the graft has healed well. He has 5/5 power to great toe dorsiflexion and a normal gait pattern. He has some residual painful scarring on the dorsum of his foot at the level of the distal attachment of the tendon graft, but we are hopeful this will resolve with time. He may require de-bulkling and debridement of the tendon graft in the future.
Spontaneous rupture to the extensor hallucis longus tendon is rare, but does have significant morbidity in a high functioning patient.
Urgent orthopaedic surgical referral is warranted if rupture of the extensor hallucis longus tendon is suspected.
Ultrasound can be an unreliable assessment of tendon rupture due to presence of tendon sheath mimicking actual tendon, and this injury is best assessed with an MRI scan.
Grafting of the tendon is an option if indirect repair is not possible. Graft options include plantaris, gracilis and palmaris longus with multiple techniques described.
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