Thumb sprains: Diagnosis and surgery
This is a common sprain, essentially of the metacarpo phalangeal joint i.e. between the first metacarpal and the first phalanx of the thumb. This lesion is frequently encountered in patients who have fallen onto their thumb, often during skiing, in combat sports or ball sports.
This joint is crucial to the stability and strength of the thumb grip, and its cohesion is ensured by two main ligaments, which are internal and external.
The lateral internal ligament is by far the worst affected by trauma, with a lesion that can range from a simple elongation to complete tear. Badly treated lesions may cause chronic pain and even functional limitation in terms of strength and there may be progressive joint destruction.
This thumb joint can quickly become swollen and painful following a fall or knock. Movement causes extensive pain. During examination, the doctor will observe specific pain at the affected ligament, in general on the inner side of the joint.
Using adapted manœuvres, the doctor will look for signs of instability which are a measure of the extent of the sprain. Indeed, the degree of pain is unrelated to the actual size of the anatomical lesion. This assessment of the seriousness of the condition is fundament in determining the course of treatment.
X-ray is usually required to investigate the possibility of bone tearing. In cases with severe pain and swelling, examination may prove difficult and this calls for the prescription of a resting splint and a delay in examination which is made several days later.
- For benign sprains, simple immobilisation for a few weeks using a splint or strapping.
- For moderately serious sprains , immobilisation for six weeks using a made-to-measure splint
- For serious sprains, i.e. with lateralinstability of the thumb which is a sign of a torn ligament, surgery is necessary to repair the ligaments. The procedure will be followed by immobilisation for four to six weeks, at the end of which the patient begins a programme of physical therapy.
Surgical repair procedure
- Hospital stay: outpatient
- Anaesthetic: regional
- Immobilisation: four to six weeks.
Access is gained to the internal lateral ligament by means of a small lateral incision. If the ligament is ruptured, it will be sutured. If it is torn from the bone it is reinserted using one or several resorbable intra-bone anchors. Immobilisation is realised, initially using a resin sprint which is then rapidly replaced by a made to measure splint, fixing the first commissure but leaving the wrist and long fingers free. The dressing is changed by a nurse every other day for two weeks.
Physical therapy is commenced after four to six weeks of immobilisation and varies in length depending on the individual patient, ranging from a few weeks to several months.
Risks following surgery
Pain may persist as a result of the operation especially if the procedure is carried out late in the development of the condition. The thumb bone may become stiff in varying degrees depending on the individual patient and this is not predictable prior to the operation.
Infection is always a possibility, but is rare for this type of procedure.
A secondary rupture or distending of the ligament may occur after a few months, depending essentially on the initial condition and the timeframe for treatment.
A loss of sensitivity may occur for a few weeks or months on the upper part of the thumb and a reduction in mobility and strength may persist for some patients.
Risks when a serious sprain is left untreated
Unfortunately, many patients are only seen a long time after the initial accident because the gravity of the sprain was not diagnosed, or else the patient has adapted to the initial discomfort. This instability becomes gradually worse and arthrosis i.e. the wearing down of the joint cartilage occurs, bringing with it the recurrence of pain or an increase in pain with a reduction in terms of mobility and the loss of efficient thumb gripping.
The surgical solutions are different, and as a final resort it may be necessary to block the joint permanently.