From the Guidelines
The proper management for a positive Kohler test, indicating an injury to the ulnar collateral ligament (UCL) of the thumb, begins with immobilization of the thumb in a thumb spica splint or cast for 4-6 weeks, as this approach is crucial for optimizing healing and preventing chronic instability 1. When managing a positive Kohler test, it's essential to consider the severity of the injury, as complete UCL tears or those with significant instability may require surgical repair.
- Immobilization should position the thumb in slight abduction and the metacarpophalangeal (MCP) joint in slight flexion to optimize healing.
- Pain management can be achieved with NSAIDs, such as ibuprofen or naproxen, along with ice application for 15-20 minutes several times daily during the acute phase.
- A progressive rehabilitation program should be initiated following immobilization, focusing on gentle range of motion exercises, followed by strengthening and proprioception training. The UCL provides critical stability to the thumb MCP joint, which is essential for pinch and grip functions, and without proper treatment, chronic instability can develop, leading to weakness, pain, and potentially arthritis in the joint, as noted in the context of acute hand and wrist trauma management 1. Key considerations in the management of UCL injuries include the identification of potential complications, such as a Stener lesion, where the aponeurosis of the adductor pollicis muscle becomes interposed between the ruptured UCL and its site of insertion, which can be identified through dynamic examination and ultrasound evaluation 1.
From the Research
Proper Procedure and Management for a Positive Kohler Test
The Kohler test is used to assess the ulnar collateral ligament (UCL) of the thumb. A positive test indicates a potential injury to the UCL. The following are key points to consider in the management of a positive Kohler test:
- Diagnosis: The diagnosis of UCL injuries is best established clinically, with the use of imaging modalities such as MRI or ultrasonography to confirm the diagnosis 2, 3, 4, 5.
- Clinical Testing: Clinical testing of UCL injuries involves demonstrating excessive laxity of the ligament. However, comparison with the uninjured contralateral thumb is unreliable in many individuals 6.
- Imaging: Ultrasonography has been shown to be a reliable and accurate method of diagnosis for UCL injuries, with excellent diagnostic accuracy for Stener lesions 5. MRI is also a useful imaging modality for confirming the diagnosis 2, 4.
- Treatment: Treatment options for UCL injuries include surgical repair, which is often offered depending on various factors such as the timing of presentation, grade of injury, displacement, and patient-related factors 2, 3.
- Surgical Complications: Surgical complications of UCL repair can include neurapraxia, with a reported incidence of 6.5% in one study 3.
Key Considerations
When managing a positive Kohler test, it is essential to consider the following:
- The use of ultrasonography or MRI to confirm the diagnosis
- The grade and severity of the injury
- The presence of any associated injuries or complications
- The patient's occupational demands and lifestyle
- The potential need for surgical intervention
Diagnostic Accuracy of Ultrasonography
The diagnostic accuracy of ultrasonography for UCL injuries has been evaluated in several studies. A meta-analysis found that ultrasonography had excellent diagnostic accuracy for Stener lesions, with a pooled sensitivity of 0.96 and specificity of 0.90 5. Another study found that ultrasonography had a sensitivity of 71.42% and specificity of 84.61% for detecting complete ligament ruptures 4.