What it is
Deltoid ligament sprains are an uncommon type of ankle sprain. A medial ankle sprain is an injury to the deltoid ligament complex on the inside of the ankle. The deltoid is a broad, strong fan of ligaments that run from the tibia (shin bone) to several bones in the foot, playing a vital role in stabilising the foot and preventing it from rolling out. Because it is robust, an isolated deltoid sprain is less common than a lateral sprain and typically requires a greater force.
People usually recall an outward roll of the foot or contact that causes the ankle to roll inward. Pain sits just below and in front of the inner ankle bone, accompanied by swelling that tracks along the arch. Weight bearing is often difficult at first.
This injury warrants careful assessment because the deltoid plays a crucial role in maintaining the ankle joint's alignment; associated fractures or syndesmosis injuries can also occur. With early protection and progressive strengthening, most cases recover without surgery when the joint remains stable.
What happens when it occurs
The classic way in which the medial ankle ligaments are damaged is the 'eversion trauma'. This means that an accident or fall causes the foot to rotate outwards under excessive force. If fibres are torn, the talus can drift laterally within the mortise under load.
Common causes and risk factors
- Contact or landing that forces the foot outward
- Prior ankle injury, limited calf and foot intrinsic strength
- Flatfoot posture and poor control during cutting or landing
Who is most affected
Field and court athletes, running and jumping sports, and falls with the foot trapped. Sports that involve repetitive short and quick changes of direction, such as football, basketball and volleyball.
Typical symptoms
- Medial (inside) ankle pain
- Swelling and bruising along the inner ankle and arch that can at times extend to the heel
- Pain with turning in, push-off, and stairs
- Pain with pressure on the inside ankle ligaments
- Difficulty bearing weight in the first days
- Feeling of instability or “giving way”, especially when walking downhill, walking down stairs or walking on uneven surfaces
- A possible “pop” or tearing sensation at the time of injury
When to seek care
Immediate assessment is advised if weight bearing is not possible, if there is bony tenderness along the inner or outer ankle, or if the ankle looks crooked under load.
How we diagnose
History and examination with valgus stress and external rotation tests, comparison of hindfoot alignment, and palpation along the deltoid. We screen for associated injury to tendons, bones in the foot and ankle, and osteochondral lesions. Imaging is used when a fracture is suspected or when instability persists, and clinicians are guided by the “Ottawa rules”.
The "Ottawa rules" are a universally accepted clinical decision-making tool used by healthcare professionals to determine if a patient with ankle or foot pain requires an X-ray to diagnose a bone fracture. The rules help avoid unnecessary imaging by providing specific criteria for bony tenderness and inability to bear weight, which can indicate a fracture and thus warrant an X-ray.
Management
- Follow professional advice for proper treatment and physical therapy.
- A comprehensive program that includes flexibility, balance, and strengthening exercises is crucial to minimise the risk of re-injury and chronic instability.
- Protection in a boot for painful grades, progressive weight bearing as tolerated
- Strength for the tibialis posterior, peroneals, and calf to control pronation and push-off
- Balance and gait retraining, then a straight-line jog to run
- Surgery is only when the ankle is unstable or when associated fractures require fixation
- Ankle taping or bracing may be used to support the joint during the recovery process.
Rehabilitation milestones
Phase 1, weeks 0 to 2: boot protection as needed, deload walking plan, range in pain-free arcs.
Phase 2, weeks 2 to 6: tibialis posterior and calf strength, supported single-leg stance, controlled pronation under load.
Phase 3, weeks 6 to 10: step-downs, hills, graded return to run, then cutting in controlled drills.
Phase 4, weeks 10 to 14: full training volume, agility, and contact progressions.
Readiness to progress
- Pain-free single-leg heel raises with controlled arch mechanics
- Balance symmetry and pain-free medial hop tests
- Running, cutting, and deceleration tasks completed without flare
Prevention
- Maintain calf and tibialis posterior strength
- Land with knees and hips flexed
- Use footwear that supports your training surface and role
Australia snapshot
- Medial ankle sprains are less common than lateral sprains and form a smaller share of ankle sprains.
- Because the deltoid is strong, isolated medial sprains often occur with other injuries; fractures and syndesmosis involvement should be excluded.
- Field and court sports provide the usual mechanisms in community and professional play.
Latest insights
Do not chase range at the expense of stability in the first two weeks.
Control pronation and restore push-off strength before adding cutting.
Use weight-bearing imaging to confirm mortise alignment when tenderness is present in the medial aspect and the walking pattern is abnormal.


