In this episode of PodMD, foot and ankle orthopaedic surgeon, Dr Hamish Curry tells us a little more about the lis franc injury; how to identify it, when to refer and more
Please note this is a machine generated transcription and may contain some errors.
*As always, all in this PODMD podcast is intended for health professionals and the comments are of a general nature. Information given is not intended as specific medical advice pertaining to any given patient. If you have a clinical issue with one of your patients please seek appropriate advice from a colleague with expertise in the area.
Dr Sean Mackay : Today I’d like to welcome to the PodMd studio Dr Hamish Curry
Hamish is an Australian trained Orthopaedic surgeon, with a special interest in surgery of the foot and ankle, specialising in bunion correction, arthritic joint fusion, foot deformity correction, fracture fixation and the management of sporting injuries.
Today, we’ll be discussing the topic of a lisfranc Injury.
*We do hope you enjoy this podcast but please remember that the advice here is of a general nature and is not intended as specific advice about a given patient. The views and opinions expressed in this podcast are those of the doctor, not PodMD.
If you do have a patient on whom you require specific advice then please seek advice from a colleague with appropriate expertise in that area.
The topic of today’s discussion is on lisfranc Injury.
So, could you start the podcast off today by telling us what is a lisfranc injury?
So, Sean, a lisfranc injury refers to injury the tarsometatarsal joints in the midfoot.
These joints are very stable due to the strong ligaments and shape of the joints.
The lisfranc ligament itself connects the medial cuneiform to the base of the 2nd metatarsal and is the keystone of the joint complex.
This area of the foot is important in maintenance of the longitudinal arch of the foot and transmits the forces from the leg to the forefoot for push off during walking.
These Injuries are relatively uncommon comprising of 0.2% of fractures. Unfortunately, up to 20% of injuries are missed which can result in long term functional loss and sequelae such as arthritis and deformity.
Injuries can be ligamentous only; they can be associated with fractures or can be a combination thereof.
So, how would a patient with a lis franc injury present to their GP?
Well, there’s 2 groups of patients who sustain these injuries.
There are high energy injuries such as car accidents or industrial crush injury. These are more often associated with severe swelling and multiple fractures and clear instability of the midfoot.
The second group and that which is more commonly seen by general practitioners is low energy injuries. They commonly occur in 20-50yr olds. They occur when the foot is in a fixed position and the patient twists or fall injuring the foot.
Patients present with pain and swelling in the middle part of the foot and an inability to weight bear.
A classic sign to look for is bruising on the sole of the foot.
There is often tenderness to palpation over the tarsometatarsal joint so on the dorsum of the foot and pain when the midfoot is stressed.
What imaging is recommended?
The diagnosis is largely made by the history, but it’s very important ahh to obtain appropriate imaging and that is to determine two things.
One is to confirm the diagnosis but the second is to determine whether the injury is a stable or unstable injury as this guides the treatment that is required.
Plain xrays are certainly the first step.
And the key point here is that initial xrays are usually non weight bearing because the patients are too painful to put their weight through it. This can actually lead to the injury being missed as subtle injuries may only be seen with weight bearing xrays.
If you have xrays which show joint displacement the diagnosis is confirmed the diagnosis is confirmed and it is confirmed unstable.
If you are seeing a patient and you have a clinical concern but initial xrays are normal you need to investigate further
There are several options for further imaging- ah weightbearing xrays can demonstrate instability of the tarsometatarsal joints. These may need to be performed often at 1 week after injury when the patient is able to weight bear. And they need to include both feet for comparison. What you’re looking for is the joints being different on each side and being unstable with translation of the joints.
The alternative is an MRI scan. This is very sensitive at assessing the lisfranc ligament and supporting ligaments and will confirm the diagnosis. But because it is non weightbearing it will not determine whether the injury is unstable which is actually key determining the treatment that’s required.
CT scan can be useful in determining the extent of fractures if they are seen the xrays but again, this is a non-weight bearing study and doesn’t determine stability.
Are there any developments or imaging techniques to help us with this?
Well, Sean in Melbourne we’re quite lucky that we do have weight bearing CT scan facilities available and that’s very helpful in determining stability. Particularly in the subtle injuries and chronic injuries. The patients do need to stand and put all their weight through their feet to complete the study.
In Melbourne, this facility is available at MIA Radiology in South Yarra.
What is the next step in management of patients with a lisfranc injury?
Well, Sean once you’ve determined, based on the clinical history and appropriate ah investigation, that they have an injury. The the the treatment is determined by the stability of the inury.
Ligaments can heal and a satisfactory outcome can be achieved without need for surgery but the joints must be stable on weightbearing imaging.
The non-operative treatment consists of 6 weeks non weightbearing in a cast or a boot followed by 6 weeks progressively weightbearing in a boot. After this period of immobilisation an After this period of immobilisation an arch support in the shoes should be worn for 6 months and physiotherapy is beneficial.
Most patients are back to their activities by 6-12 months from their original injury.
If there is any instability of the tarsometatarsal joints seen on imaging, then surgery is recommended to obtain anatomical reduction and improve long term outcomes. This involves plate or screw fixation with a similar period of three months immobilisations followed by metalware removal at 6 months and in some cases joint fusion is advocated.
What are the outcomes beyond that?
The outcomes after this injury vary and are largely dependent on whether it is a high vs low velocity injury and the extent of the injury to the tarsometatarsal joint complex.
We know that anatomical reduction is also a contributing factor to outcome and the importance therefore in determining if the injury is stable or not and if it’s surgically stabilised that it is anatomical.
In the group of lower energy injuries the majority of patients will return to their pre injury level of function. Chronic pain can be a long term problem. Development of arthritis, I’ll say that again.. Development of arthritis is also common in the longer term even with anatomically stabilised injuries and fusion surgery may be required.
A return to full sporting activity can take 6 to 12 months after the injury.
Outcomes are poorer in untreated injuries with development of arthritis, deformity is very common with resultant functional impairment.
What things should a GP consider when dealing with a Lisfranc injury?
The most important thing is to consider the possibility that there is an injury. If it is not considered, then it is likely to be missed.
Acutely Acutely the important things to consider are mechanism of injury, location of pain and presence of plantar bruising. This should prompt the ordering of further investigation to determine if there is an injury and if it is unstable.
Chronic injuries often present with more diffuse midfoot pain and functional impairment such as reduced push off strength, pain and inability to return to sport.
Overall, imaging is crucial in the decision making and ordering of weightbearing imaging is vital to determine stability of the joints and therefore the pathway for treatment.
When should a GP refer?
Referral should occur for patients with an unstable injury as this requires surgery.
It is important to refer those cases where there may be a question about stability or the imaging is equivocal.
Early referral is preferable because of the poorer outcomes are seen untreated cases. And acutely we have a 2-3 week surgery window … Surgery is ideally performed within a 3 week window following the acute injury. So early referral is beneficial for both surgeon and patient.
Thank you for your time here today in the PodMD studio. To sum up for us, could you please identify the three key take home messages from today’s podcast on a lisfranc injury.
So, the 3 points I think to have are:
Have a clinical suspicion of the injury based upon the patient’s history and examination.
The second key point is to obtain appropriate imaging to confirm the injury which must include a weightbearing xray or CT scan.
Early referral for unstable injuries is vital to ensure they require appropriate surgical treatment. Early referral for unstable injuries is vital to ensure appropriate anatomical, surgical treatment.
Thanks again for your time and the insight’s you’ve provided.
Thanks very much, Sean