Ankle, Midfoot and Forefoot osteoarthritis (OA)
Symptomatic ankle osteoarthritis (OA) is not uncommon, affecting 1% of the general population Epidemiology of osteoarthritis – PMC. Symptomatic midfoot and forefoot OA is more prevalent, affecting 12% of adults over the age of 50 The epidemiology of symptomatic midfoot osteoarthritis in community-dwelling older adults: cross-sectional findings from the Clinical Assessment Study of the Foot – PubMed.
Common sites include the talocrural joint, subtalar joint, tarsometatarsal (TMT) joints and the 1st metatarsophalangeal (MTP) joint (big toe). The condition is characterised by the gradual breakdown and destruction of the smooth articular cartilage that covers the joint articulations. This leads to subsequent reactive bony changes in the subchondral bone, development of osteophytosis (bony spurs) and joint space loss. Ultimately resulting in pain, stiffness and functional loss for the patient.
The main risk factor for developing osteoarthritis in the midfoot, but especially the ankle, is previous trauma/fracture, present in 75% to 80% of all cases Ankle Osteoarthritis Aetiology – PMC. Other causes include chronic ligament instability, obesity, metabolic disease, genetics and female sex. Patients with ankle osteoarthritis tend to be younger than their counterparts with hip and knee osteoarthritis and progression to advanced stage osteoarthritis is usually quicker with a more rapid loss of function. Ankle Osteoarthritis Aetiology – PMC
What are the signs and symptoms?
Patients with ankle OA typically complain of weight-bearing anterior ankle pain, but symptoms can also affect the medial and/or the lateral margins. They have associated stiffness that may also be accompanied with some crepitus. With the progression of the disease, pain can become prevalent at rest, and patients often have nocturnal symptoms (night pain).
Midfoot OA can affect any of the articulations but is more common in the talonavicular and TMT joints. Patients complain of weight-bearing midfoot pain but without the associated stiffness there often is with the ankle. Ambulation becomes difficult, and there is often palpable osteophytosis (bony spurs) over the dorsal aspect of the affected joints with localised tenderness.
Finally, osteoarthritis in the forefoot is often confined to the 1st MTP (big toe), with localised symptoms, stiffness, and often joint swelling. This is, however, a common site for asymptomatic OA, with 66% of 80-year-olds having radiographic evidence but without symptoms. Incidence and management of first metatarsophalangeal joint osteoarthritis in Dutch general practice estimates from the Rijnmond Primary Care Database – ScienceDirect
How is it diagnosed?
The diagnosis will be made from a combination of your clinical history, examination findings and often a plain film X-ray.
The clinical symptoms have been discussed already. X-rays will be helpful at ascertaining the level of degeneration and, in the case of the midfoot, confirming the location. It will be helpful prognostically but also help guide potential intervention. X-rays will show the classical radiographic features of joint space loss, sclerosis and osteophytosis.
MRI can be helpful if there is suspicion of concurrent or alternative bony pathology, such as bone stress injuries or atypical features. Ultrasound is not usually indicated in the workup of osteoarthritis but can often see the degenerative changes, especially in the midfoot and forefoot, and will be more commonly utilised for targeted and accurate interventional procedures in real time.
How are they treated?
Treatment options are divided into conservative and surgical.
Conservative options:
- Oral analgesia in combination with modifications of daily activities may help alleviate some of the symptoms, especially in the early stages of the disease, or allow acute exacerbations to settle down.
- Foot orthotics for patients with midfoot osteoarthritis have been shown to be helpful. optimising foot biomechanics and unloading symptomatic joints. Foot orthoses in the treatment of symptomatic midfoot osteoarthritis using clinical and biomechanical outcomes: a randomised feasibility study – PMC
- Ultrasound-guided injections into the hindfoot, midfoot and forefoot for symptomatic OA have been shown to be beneficial in the short to medium term. Efficacy of non-surgical interventions for midfoot osteoarthritis: a systematic review – PubMed. These can be repeated at sensible intervals if helpful.
- In less severe cases of osteoarthritis, an ultrasound-guided hyaluronic acid injection into the ankle joint can be helpful as a potential alternative to repeated steroid injections. They have a very safe injection profile and can be an effective alternative in certain patients. Hyaluronic acid as a treatment for ankle osteoarthritis – PMC. However, its efficacy, especially in patients with advanced osteoarthritis, is challenged. Limited Evidence to Support the Use of Intra-Articular Hyaluronic Acid for the Treatment of Ankle Osteoarthritis: A Systematic Review and Meta-Analysis of Randomized Control Trials – PubMed
Surgical options:
If conservative options do not provide adequate relief or if there is already substantial arthrosis on a plain film X-ray at time of initial presentation then there are surgical options.
- Arthrodesis (joint fusion) is the most common surgical solution for patient with advanced OA around the foot and ankle especially in the younger, high demand patient. It has excellent outcomes though both arthroscopic and open techniques in addressing hindfoot, midfoot and forefoot OA. Clinical effectiveness of arthroscopic vs open ankle arthrodesis for advanced ankle arthritis: A systematic review and meta-analysis – PubMed
- Ankle arthroplasty (joint replacement) is an alternative surgical option. The ideal candidate is usually older with an anatomically aligned ankle and heel. Who has a relatively preserved range of movement with at least 5 degrees of ankle dorsiflexion? Ankle arthroplasty: A review and summary of results from joint registries and recent studies – PMC. Thus, ankle arthroplasty is not suitable for every patient.
- 1st MTP arthroplasty (Joint replacement of the Big toe). This technique compared to arthrodesis (fusion) preserve the biomechanics of the joint allowing better functional use Arthrodesis versus Arthroplasty of the First Metatarsophalangeal Joint in the Treatment of Hallux Rigidus – A Comparative Study of Appropriately Selected Patients – PubMed however complications may be higher, with implant failure and osteolysis not being uncommon. Republication of “Current Concepts Review: Hallux Rigidus” – PMC
- Cheilectomy which is a less invasive procedure involving the removal of dorsal osteophytes (bony spurs) from the 1st MTP, can be helpful in certain patients. Republication of “Current Concepts Review: Hallux Rigidus” – PMC
Finally, osteotomy techniques are joint-preserving techniques that can be used in certain individuals with valgus or varus ankle malalignment, aiming to redistribute weight-bearing forces to preserved cartilage. Supramalleolar osteotomy for the treatment of ankle osteoarthritis leads to favourable outcomes and low complication rates at mid-term follow-up: a systematic review – PubMed
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