Introduction
Carpal instability refers to the misalignment of the small bones in the wrist, which disrupts normal joint function. This condition can occur when the ligaments that stabilize the bones are torn, or when fractures or arthritis affect the bones. As a result, individuals may experience chronic pain and diminished wrist function. Fortunately, both nonsurgical and surgical treatment options can help alleviate symptoms.
Anatomy
The wrist is composed of several small carpal bones arranged in two rows, interconnected by a complex network of ligaments. These carpal bones, together with the two bones in the forearm, form multiple joints within the wrist. These joints enable various movements and shape changes in the hand, facilitating precise actions like handwriting and gripping objects such as a steering wheel.
Causes
Carpal instability arises when the carpal bones shift from their normal positions. This misalignment can result from chronic ligament weakness associated with conditions like arthritis or acute ligament injuries from falls. Additionally, fractures of the carpal bones and their deterioration can lead to instability. When the carpal bones are misaligned, the resulting instability can impair joint function.
Symptoms
Individuals with carpal instability often experience persistent wrist pain. Symptoms may include:
- A snapping sensation or audible clicking when moving the hand side to side
- Weakness and stiffness in the hand and wrist
- Difficulty using the hand for everyday activities
- Over time, the development of arthritis in the affected hand
Diagnosis
To diagnose carpal instability, your doctor will assess your medical history and conduct a physical examination. It’s important to inform your doctor about any wrist injuries and how they occurred.
Your doctor will examine the ligaments and bones in your hand to identify the source of pain. They may manipulate the carpal bones to assess specific areas of instability.
X-rays will be taken to evaluate the position and condition of the carpal bones. Additional imaging tests, such as computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, arthrograms, and ultrasounds, may also be utilized.
Your doctor will categorize the pattern of instability present in your carpal bones. Several types of carpal instability patterns exist, including:
- Dissociative carpal instability: Instability occurring between carpal bones within a single row.
- Nondissociative carpal instability: Instability between the two rows of carpal bones.
- Ulnar translocation: A shift of the carpal bones toward the little finger side, often associated with rheumatoid arthritis.
- Dorsal subluxation: An upward shift of the carpal bones, which may happen following a wrist fracture.
Carpal instability can also be classified as static or dynamic. Static instability is visible on an X-ray when the hand is at rest, while dynamic instability is noted when the doctor is able to move the carpal bones during tests.
Treatment
Treatment strategies are tailored to the specific type of carpal instability experienced. Various factors, such as the condition of the ligaments and bones, as well as the location of the instability, influence treatment decisions. Addressing carpal instability can be complex; some cases may respond well to splinting, while others might necessitate surgical intervention. Your doctor will discuss your condition in detail and recommend the most appropriate treatment options.
Surgery
There are various surgical approaches for treating carpal instability, with the specific type of surgery determined by your individual condition. Surgical options may include:
- Repairing and reconstructing ligaments, potentially using transferred tendons.
- Fusing joints or reshaping bones to enhance stability and relieve pain.
Arthroscopic surgery is frequently employed in the treatment of carpal instability. This minimally invasive procedure utilizes a small instrument known as an arthroscope, which contains a lens and lighting system for viewing inside the joint. The surgeon can perform the procedure through small incisions rather than fully opening the joint. A miniature camera attached to the arthroscope allows the surgeon to observe and document magnified images on a video screen. Thin surgical instruments are then introduced to perform necessary repairs, including reconstructing, trimming, and repairing torn ligaments.
Recovery
After surgery for carpal instability, a period of immobilization using splints or casts is typically required, followed by rehabilitation through hand therapy. The recovery process is individualized, and your doctor will provide guidance on what to expect as you heal.
