Soft tissue injuries of the ankle are common, accounting for almost one
quarter of all sporting injuries. A Year on Foot at the ISEH has been
following closely one such high-profile ankle problem sustained during
contact sport as Mr Michael Oddy, ISEH Consultant Trauma &
Orthopaedic Surgeon reports:
"February has seen the start of the Six Nations Rugby Union competition
and an injury to the Welsh outside-half required significant strapping
to his left ankle before heading to the sidelines mid-way through the
first half of one of the opening games. The post-match press conference
reported concern that he had sustained a ‘high ankle sprain’ although
his rapid recovery during the week, in time to make the team sheet for
the second game of the tournament, made the diagnosis unlikely.
Most ankle soft tissue injuries are inversion or inward tilting mechanisms which sprain or tear the lateral talofibular ligaments on the outer side of the ankle. Higher energy contact sports, such as American football or rugby, with an eversion or outward tilting and twisting rotation can produce a more extensive injury to the ankle syndesmosis – the fibrous joint which binds the tibia and fibula together at the ankle. The tibiofibular ligaments blend with an inter-osseous membrane between the leg bones spanning the whole length of the lower leg and an injury to this anatomical area has been termed a ‘high ankle sprain’ accounting for approximately one quarter of all ankle sprains. In the short term, high ankle syndesmosis sprains are associated with a significantly slower recovery and return to sport than standard lateral ankle sprains. The long term sequelae can include scar soft-tissue impingement, calcification and stiffening of the inter-osseous membrane of the leg, chronic syndesmosis instability with the potential for future degenerative change.
The clinical signs of a high ankle sprain can demonstrate swelling and bruising around the ankle with pain over the front of the lower leg and ankle which is worse with external-rotation stressing the ankle or squeezing the tibia and fibula bones together. There can also be associated swelling and bruising suggesting a medial deltoid ligament injury. Suspicion of a high ankle sprain based on clinical assessment requires an X-ray of the ankle joint, ideally standing if tolerated, to demonstrate the bony anatomy of the ankle joint and exclude any associated fractures which can be part of the injury mechanism. High definition Magnetic Resonance Imaging (MRI) scanning available at ISEH is highly sensitive in detecting the presence of syndesmotic ligament injuries and other concomitant injuries such as injuries to the joint surface cartilage.
The aim of clinical examination and imaging is to identify those high ankle sprains with mechanical instability - the physical widening of the syndesmosis which needs surgical stabilisation, versus those which are stable and can be managed non-operatively. Injuries with definite evidence for mechanical instability are usually fairly clearly identifiable; it is those with incomplete injuries that may only demonstrate late instability under the stress of sporting activity which represent the challenge in diagnosis and treatment. If tolerated, a ‘stress X-ray’, with the leg forced into external-rotation, can help demonstrate whether there is instability as indicated by a change in the bony anatomy of the normal ankle joint shape with a dynamic widening of the syndesmosis and separation of the tibia and fibula. Direct vision of the syndesmosis under arthroscopic surgical assessment of the joint can also provide definite evidence for mechanical instability between the ankle bones.
Stable and incomplete high ankle sprains can be managed non-operatively with rest, cryotherapy, pneumatic walker boot immobilisation and graded physical therapy. A probable return to sport can be likely over four to six weeks post injury. Surgical treatment of unstable injuries requires fixation of the syndesmosis using a screw or a ‘Tight-rope’ suture button with a probable return to sport over nine to twelve weeks. Even with successful diagnosis and treatment of a high ankle sprain, there can be a degree of swelling, pain and soft tissue impingement requiring ultrasound-guided steroid injections.
Detailed epidemiological data and the impact of high ankle sprains on Rugby Union players in the professional era are still yet to be determined fully and most of our knowledge regarding this injury comes from American football. Unfortunately, however, the time-zone difference meant that A Year on Foot at the ISEH was unable to remain awake for February’s Super Bowl 50.