An ankle injury could range from a simple soft tissue sprain to a fracture. Injury to the talar dome is an injury to part of the ankle joint. The talar bone is one of the major bones that make up the joint. An ankle sprain is a soft tissue injury to the ligament structure around the ankle joint most often occurring as you roll on your foot. Ligaments stabilise joints and prevent excess movement so it stands to reason that if you have a significant soft tissue injury causing lack of stability then the joint may become unstable and may roll so much that the actual joint or part of is damaged. If severe this may cause a talar dome injury. The dome aspect of the talus bone, which is the joint surface, becomes damaged. A talar dome injury may be just to the cartilage attached to the bone or to the bone itself or a combination of both. It is most often diagnosed by bone scan and may not picked up by xray. A xray will often be taken immediately after the injury and if it shows nothing then the ankle will be classed as just a sprain and treated conservatively with physiotherapy. If the injury does not heal at a certain pace then there may indeed be bone injury and a bone scan/MRI may be needed to find what else is injured.
Treatment of this type of injury varies depending on the severity. A severe talar dome fracture where the bone is displaced will usually need internal fixation under surgery. This type of injury would usually be found on xray immediately, as it should be quite obvious. Other less severe injuries may require a plaster for a few weeks. Others may just require non-weight bearing through the ankle, while very mild talar dome injuries will be treated as a normal sprain except it is accepted that they will take longer to heal than your normal 4-6 weeks.
You need to find out how severe your injury is and get some guidelines to management through your doctor and physiotherapist. Just remember these types of injuries have the same long-term complications as your ankle sprains ie. Ankle stiffness, balance problems, recurrent injury so get some management and exercise advice from your local physiotherapist if you are at all unsure. Early Physiotherapy especially ankle mobilisation and exercise will prevent long term complications.
