Carpal Instability

What Is Carpal Instability? Causes and Symptoms

If you experience wrist clicks when moving or have an unstable grip during lifting, these could be signs of underlying carpal instability, potentially related to injuries of the carpal ligaments.

Carpal instability is defined as an injury where there is a loss of normal alignment of the carpal bones and/ or the radioulnar joint. This loss disrupts the normal balance of the carpal and radioulnar joints, leading to changes in the range of motion. It can be considered a form of carpal dysfunction, implying that a normal wrist's ability to transfer loads without sudden changes in stress on the articular cartilage (normal kinetics) and move throughout the normal range without sudden alterations of intercarpal alignment (normal kinematics) is impaired. Patients often report pain and a sensation of “giving way” when performing specific tasks. This can also manifest as recurrent wrist weakness or a "slipping" or "catching" sensation, although the literature does not explicitly use the term "recurrent wrist weakness" but describe the functional limitations and sensations of instability.

Causes of carpal instability are varied and can include:

• Traumatic events such as a fall on an outstretched hand (often with the wrist in hyperextension and forearm pronated), distal radius fractures, and scaphoid fractures. These traumas can cause ligamentous injuries leading to misalignments. Isolated SLIL (scapholunate interosseous ligament) disruption alone is usually insufficient to cause dorsal intercalated segment instability. Damage to both intrinsic and extrinsic ligaments is generally necessary for instability to occur.
• Chronic ligament weakening.
• Chronic repetitive stress, such as in paraplegics who use their extremities for weight support.
• Microcrystal deposits due to underlying diseases like ulnar minus variance or metabolic diseases such as rheumatoid arthritis, gout, or pseudo-gout.
• Rotational force to the wrist can also cause ligamentous injuries.
• Chronic friction of supporting ligaments over time, even after a minor initial injury.
• Iatrogenic causes.
• Congenital diseases.
• Inflammation.
• Infection.
• Tumor.
• Malunited fractures of the distal radius can lead to adaptive carpal instability.
• Trapeziectomy for trapeziometacarpal osteoarthritis can disrupt the scaphotrapezium-trapezoidal ligament complex and may be associated with carpal collapse.

Symptoms of carpal instability can include:

• Pain.
• A sensation of “giving way” during specific activities.
• Decreased grip strength.
• Painful popping or clicking with activities.
• Diffuse swelling in acute injuries.
• In more severe cases, visible malalignment of the wrist.

Carpal instability can be classified based on whether the misalignment is visible on imaging or occurs only during movement:

• Static instability: In this type, misalignment of the carpal bones is permanent and visible on plain radiographs, regardless of the load applied. Examples include dorsiflexed intercalated segment instability (DISI) and volarflexed intercalated segment instability (VISI).
• Dynamic instability: Here, the wrist appears well-aligned and may be able to sustain physiological loads most of the time, but malalignment and symptoms (like pain or a "giving way" sensation) appear sporadically under certain loading conditions or during specific movements. Special stress radiographs or fluoroscopy may be needed to demonstrate the abnormal carpal positioning. Occult instability represents a milder form where static and stress radiographs might be normal, but the patient experiences pain or dysfunction with mechanical loading.

Anatomy of the Unstable Wrist: Ligaments and Sensorimotor Control

• Key structures: scapholunate ligament (most commonly injured), lunotriquetral ligament, TFCC (triangular fibrocartilage complex), and neuromuscular feedback loops.
• Explain how ligament tears or laxity disrupt carpal alignment and grip mechanics.

Causes and Risk Factors for Carpal Instability

Anatomy of the Unstable Wrist: Ligaments and Sensorimotor Control

The wrist's stability is maintained by a complex interplay of intrinsic and extrinsic ligaments. Injuries to these ligaments, particularly the scapholunate ligament (SLIL), are frequently the primary cause of carpal instability.

Key Ligamentous Structures in Wrist Instability:

• Scapholunate Interosseous Ligament (SLIL): The SLIL is considered the primary stabilizer of the scapholunate joint, if not the entire carpus. It binds the scaphoid and lunate together. The SLIL has three subregions (dorsal, proximal, and volar), with the dorsal component being the thickest, strongest, and most critical for stability, resisting distraction, torsional, and translational moments. Isolated disruption of the SLIL, while it may not cause immediate static malalignment, can lead to abnormal force transmission and kinematics, potentially progressing to dynamic instability and eventually static instability.
• Lunotriquetral Ligament (LTIL): Along with the SLIL, the LTIL is another functionally important intrinsic ligament connecting the lunate and triquetrum. Disruption of the LTIL can lead to lunotriquetral instability, sometimes resulting in a volar intercalated-segment instability (VISI) pattern.
• Secondary Ligamentous Stabilizers: Several extrinsic and intrinsic ligaments act as secondary stabilizers to the scapholunate joint. These ligaments are usually insufficient to cause instability when injured in isolation but become critical when the SLIL is compromised.
  • Volar Extrinsic Ligaments: These include the radioscaphocapitate (RSC), long radiolunate (LRL), short radiolunate (SRL), and radioscapholunate (RSL) ligaments. The LRL has gained attention as a potential critical stabilizer of the lunate, and its injury has been associated with SLIL injuries. Sectioning the LRL along with the SLIL has been shown to increase the radiolunate angle, indicating a stabilizing effect on lunate extension.
  • Dorsal Extrinsic Ligaments: The dorsal intercarpal (DIC) and dorsal radiotriquetral (DRC) ligaments have attachments to the lunate and provide secondary stability. The DIC has insertions on the lunate (DICL) and scaphoid (DICS), and disruption of these insertions, especially with SLIL injury, can lead to dorsal intercalated segment instability (DISI).
  • Scaphotrapeziotrapezoid (STT) Ligament: This volar ligament complex is another important secondary stabilizer of the scaphoid. Disruption of the STT ligament along with SLIL injury has been shown to produce dorsal intercalated segment instability.

Disruption of Carpal Alignment and Grip Mechanics:

Tears or laxity in these ligaments disrupt the delicate balance and kinematic relationships between the carpal bones.

• Loss of Normal Alignment: Injury to the SLIL, especially when combined with damage to secondary stabilizers, allows the scaphoid to flex and the lunate to extend, leading to a rotatory subluxation of the scaphoid and potentially a DISI deformity. Similarly, LTIL injuries can lead to abnormal flexion of the lunate (VISI deformity). The loss of synchronous motion and normal alignment between the scaphoid and lunate defines scapholunate dissociation.
• Impact on Grip Mechanics: The carpal bones work together to provide a stable base for the hand and efficient transfer of forces during grip. When carpal alignment is disrupted due to ligamentous injury, the efficiency of force transmission is compromised, potentially leading to decreased grip strength and a sensation of weakness or "giving way". The altered carpal kinematics can cause pain and further inhibit normal hand function.

Sensorimotor Control (Carpal Proprioception):

It is understood that the ligaments and joint capsules contain mechanoreceptors that provide sensory information about joint position and movement. Ligament tears and chronic instability would inherently disrupt this normal sensory feedback. This disruption can contribute to a feeling of instability, incoordination, and difficulty with fine motor control, further impacting grip and overall hand function. The altered kinematics resulting from ligamentous injury lead to abnormal mechanical signals and likely affect the sensorimotor pathways involved in maintaining wrist stability and coordinating hand movements.

Why Physiotherapy is Essential for Carpal Instability

Physiotherapy plays a crucial role in the management of carpal instability by addressing both ligament integrity through stabilization techniques and functional deficits such as reduced grip strength and impaired coordination. While surgery may be preferred in many cases, physiotherapy is often a key component of both non-operative and post-operative care.

Addressing Ligament Integrity and Stability:

• For minor carpal instability where more than 80% of normal range of motion and grip strength is maintained, non-operative treatment, including physiotherapy, is often appropriate.
• Physiotherapy interventions focus on supporting and stabilizing the carpal bones, especially in cases of dynamic instability where misalignment occurs under load.
• Immobilization using splints or casts is a common initial step in conservative management. Specific splints, like forearm-based wrist support splints with pressure pads, can be used to control the movement of specific carpal bones like the scaphoid and trapezoid, thus aiding in stabilization.
• Avoiding movements that cause pain is crucial during the initial immobilization period to protect the injured ligaments.
• As symptoms reduce, dynamic strengthening exercises can be introduced to improve the strength of the muscles surrounding the wrist, which can contribute to overall stability. These exercises aim to compensate for ligamentous laxity by enhancing muscular support.
• The overall goal of restoring normal carpal kinematics aligns with physiotherapy's focus on rehabilitation and functional movement.

Addressing Functional Deficits:

• Carpal instability often leads to pain and a sensation of "giving way," which can significantly impact the ability to perform daily tasks and reduce grip strength. Physiotherapy aims to alleviate these symptoms and improve function.
• Regaining full range of motion after immobilization or surgery is a primary goal of physiotherapy. Specific exercises and manual therapy techniques can be used to address any stiffness and improve joint mobility.
• Improving grip strength is another essential aspect of physiotherapy. Targeted strengthening exercises for the wrist and forearm muscles are implemented to enhance the ability to perform tasks requiring a strong grip.
• Coordination and proprioception (the sense of joint position) are often affected by carpal instability. Physiotherapy programs include exercises designed to improve fine motor control and the wrist's ability to sense its position in space, contributing to better overall hand function.

Preventing Progression to Osteoarthritis or Chronic Pain:

• Undiagnosed or poorly managed carpal instability can lead to progressive limitation of movement, degenerative intercarpal and radiocarpal arthritis, chronic pain, and disability.
• By restoring proper alignment and kinematics and improving the wrist's ability to bear physiological loads, physiotherapy can help reduce abnormal stress on the articular cartilage, thus potentially slowing down or preventing the onset of osteoarthritis
• Effective management of pain through various physiotherapy modalities and exercises can help prevent the development of chronic pain associated with long-standing carpal instability.

In summary, physiotherapy is essential for carpal instability as it provides a structured approach to stabilize the wrist, improve strength and coordination, reduce pain, and ultimately prevent or slow the progression of degenerative changes and chronic pain. It plays a vital role in both conservative management of milder cases and post-surgical rehabilitation to ensure optimal functional recovery.

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Prognosis: Can Carpal Instability Be Cured?

The prognosis for carpal instability varies depending on the severity, chronicity, and type of instability, as well as the timeliness and appropriateness of the intervention. While a complete "cure" in the sense of returning to a pre-injury, completely unrestricted state may not always be achievable, significant improvement in symptoms and function is often possible with appropriate management. Early intervention is indeed critical to help avoid the development of degenerative changes and chronic pain.

Timeline for Improvement and Recovery:

• Non-operative Management (including physiotherapy): For minor carpal instability where a significant range of motion and grip strength are maintained, a period of non-operative treatment including immobilization and physiotherapy may lead to improvement. While clinically suggested to see improvement in 8–12 weeks with consistent rehab, the evidence does not provide a specific universal timeline for non-operative recovery. The duration of immobilization and the progression of physiotherapy will depend on the individual case and the specific ligaments involved. It is noted that non-operative treatment is generally considered for minor disability.
• Surgical Intervention: More severe or chronic cases of carpal instability, especially those involving significant ligament tears or malalignment, may require surgical intervention such as ligament repair or carpal fusion. The recovery timeline after surgery is typically longer and involves a period of immobilization followed by extensive physiotherapy to regain range of motion, strength, and function. Again, the exact timeline will vary based on the surgical procedure performed and individual healing. For instance, after scapholunate ligament repair and capsulodesis, immobilization in a cast for at least two months is common. Return to full activity, especially for high-demand individuals, can take several months.
• Long-Term Outcomes: Even with successful treatment, some patients may experience residual stiffness, weakness, or occasional pain, particularly with high-demand activities. In some instances, despite intervention, degenerative changes like osteoarthritis can still progress over time. Procedures for advanced stages of degeneration (like SLAC wrist) are often referred to as "salvage" procedures, indicating that the goal is to manage the existing condition rather than achieve a complete cure.

Importance of Early Intervention:

Untreated carpal instability can lead to a cascade of problems, including abnormal carpal kinematics, increased stress on joint surfaces, cartilage wear, and the eventual development of degenerative arthritis (osteoarthritis). Early diagnosis and appropriate management, whether conservative or surgical, aim to restore proper carpal alignment and kinematics, thereby reducing abnormal load transfer and potentially slowing or arresting the degenerative process. Delay in treatment can lead to more complex and less predictable outcomes, with established malalignment and secondary ligament injuries making successful restoration more challenging.

In conclusion, while a guaranteed "cure" for all cases of carpal instability may not be possible, significant functional improvement and pain reduction can often be achieved, especially with early and appropriate intervention, which may include physiotherapy alone for mild cases or surgery followed by rehabilitation for more severe injuries. Early intervention is crucial to mitigate the risk of long-term complications such as degenerative arthritis. The specific prognosis depends on numerous factors, and a thorough evaluation by a healthcare professional is essential for determining the most suitable treatment plan and understanding the expected recovery trajectory.

Preventing Recurrent Carpal Instability; Physiotherapy Treatment for Carpal Instability

Physiotherapy plays a significant role in the management of carpal instability, both non-operatively for milder cases and post-operatively as part of rehabilitation. The approach to physiotherapy treatment involves several key components, aligning with the aspects you've outlined.

Biomechanical Assessment

A thorough biomechanical assessment is crucial for diagnosing and guiding the treatment of carpal instability. This assessment typically includes:

• Evaluation of ligament integrity and laxity: Clinical examination involves specific tests, often called ‘provocative or stress tests’, that reproduce or provoke an individual’s pain by stressing the ligaments, helping to identify which carpal ligaments might be affected.
• Assessment of joint play: This involves evaluating the passive movement between the carpal bones to identify any restrictions or abnormal mobility.
• Evaluation of dynamic movements: This includes observing wrist motion during functional tasks and performing specific tests like the Watson or scaphoid shift test to assess for instability. The scaphoid shift test, described by Watson, involves applying pressure to the scaphoid tubercle while moving the wrist from ulnar deviation and slight extension to radial deviation and slight flexion. Pain or a clunk during this maneuver can indicate scapholunate instability. Fluoroscopic evaluation under anesthesia can also provide valuable kinematic information. Radiographic stress views can also be used to detect dynamic instability.

Strengthening Exercises

Strengthening exercises are a key component of physiotherapy to support the wrist and improve function.

• Forearm and Grip Strengthening:
  • The focus is often on achieving a balance between the wrist extensor and flexor muscles to provide dynamic stability to the carpus. Examples of exercises, would include wrist curls (flexion and extension), exercises using therapy putty for grip and finger strengthening, and potentially rice digs for wrist and forearm muscle activation.
  • The use of resistance bands can be incorporated to provide resistance during wrist flexion, extension, radial deviation, and ulnar deviation exercises, contributing to overall wrist stabilization.
• Scapholunate Stabilization Drills:
  • The principles of rehabilitation involve strengthening the muscles that influence the scaphoid and lunate, as well as improving proprioception around the wrist.
  • Isometric holds of the wrist in various positions can help activate and strengthen the surrounding muscles without excessive joint movement.
  • Controlled rotation exercises with light resistance might be used to improve the coordinated movement of the scaphoid and lunate with the rest of the carpus. The goal is to restore normal carpal kinematics.
  • Wrist proprioception exercises would likely be included to improve the sense of joint position and control around the scapholunate joint.

Sensorimotor and Coordination Training

Sensorimotor and coordination training are important for regaining fine motor control and stability in the wrist.

• The use of balance boards (e.g., wobble boards) can challenge the neuromuscular system to maintain stability and improve proprioception in the wrist and forearm during weight-bearing or dynamic movements.
• Ball-catching drills and other tasks requiring coordinated hand and wrist movements can help enhance neuromuscular control and improve the wrist's ability to react to external forces and maintain stability.

Manual Therapy

Manual therapy techniques can be used to address pain, stiffness, and carpal alignment.

• Gentle carpal joint mobilizations may be performed by a physiotherapist to improve the alignment and movement of the individual carpal bones, addressing any restrictions that may be contributing to instability or pain.
• Scar tissue release techniques might be used if there is post-surgical scarring that is limiting movement or causing pain.

Splinting and Taping

External supports can play a role in managing carpal instability.

• Custom splints may be used during the acute phases of injury or symptom exacerbation to immobilize the wrist and provide support to the injured ligaments, allowing them to heal. Forearm-based wrist support splints with pressure pads can be used to control specific carpal bone movements.
• Kinesiology taping or other forms of taping may be used to provide support during activities, improve proprioceptive feedback, and potentially influence muscle activation around the wrist.

Ergonomic Modifications

Modifying activities and the environment to reduce stress on the wrist is an important aspect of long-term management.

• Adjustments to workstation setup, including the positioning of the keyboard, mouse, and other tools, can help minimize strain on the wrist.
• Modifying typing techniques to maintain a neutral wrist posture can also be beneficial.
• Education on proper body mechanics and avoiding activities that aggravate wrist symptoms are crucial for preventing recurrence or progression of instability.

Overall, physiotherapy treatment for carpal instability is a multifaceted approach that includes a thorough assessment, targeted exercises to improve strength, stability, and coordination, manual therapy techniques, the use of external supports, and ergonomic advice to minimize strain and promote long-term wrist health. The specific treatment plan will be tailored to the individual's presentation, the type and severity of instability, and their functional goals.

FAQs About Carpal Instability

• "Is carpal instability permanent?"Carpal instability can manifest as either dynamic instability, where misalignment occurs only under certain loads, or static instability, where malalignment is permanent regardless of the load applied. If undiagnosed, carpal instability can lead to progressive limitation of movement and later to degenerative intercarpal and radiocarpal arthritis, chronic pain, and disability. However, it's also noted that carpal instability is frequently asymptomatic and may not require treatment. The chronicity of carpal instability is one of the six criteria proposed by Larsen et al. to guide treatment decisions, considering the healing potential of the involved ligaments. Acute ligament lesions might be treated with open surgery and pin fixation for stability. Chronic ligament lesions without arthritis can be managed with different methods. In cases of scapholunate instability, the condition is described as a spectrum of injury, ranging from occult to dynamic to static dissociation, potentially leading to irreversible changes and scapholunate advanced collapse (SLAC) over time if not addressed. Therefore, while some forms of carpal instability can become permanent, early diagnosis and appropriate management aim to prevent progression and restore stability.
• "Can wrist instability lead to arthritis? "Yes, sources indicate that carpal instability can lead to arthritis. The main problem with carpal ligament lesions and fractures is the high potential for arthritis. If carpal instability is undiagnosed, it can progress to degenerative intercarpal and radiocarpal arthritis. In the context of scapholunate instability, untreated injuries can lead to abnormal kinematics and load transfer, eventually resulting in predictable progressive degenerative changes known as scapholunate advanced collapse (SLAC). This arthritis first develops along the scaphoid facet of the distal radius, then within the radial midcarpal joint, and finally involving the entire carpus.
• "How is this different from carpal tunnel syndrome?"Carpal instability involves a mechanical problem with the alignment and movement of the carpal bones and the ligaments that stabilize them. Carpal tunnel syndrome, on the other hand, is a condition where the median nerve is compressed as it passes through the carpal tunnel in the wrist. While both conditions can cause wrist pain and dysfunction, they affect different structures and have different underlying causes.
• "When is surgery necessary?"Surgery is often considered for carpal instability, especially in cases of acute ligament lesions, significant instability, or when conservative treatment is insufficient. For acute ligament lesions, open surgery with pin fixation for stability is often recommended. In dynamic instability and scapholunate dissociation with a repairable SLIL, open reduction, ligament repair (e.g., scapholunate repair), and capsulodesis are common surgical approaches. Surgery may also be necessary for perilunate dislocations and fracture-dislocations of the carpus. In more advanced stages of scapholunate instability, particularly with arthritis (SLAC), salvage procedures like four-corner arthrodesis or proximal row carpectomy might be considered. Larsen et al.'s criteria for analyzing carpal instability (chronicity, constancy, etiology, location, direction, pattern) help guide the decision-making process for surgical treatment. Surgeons may prefer to operate if there is possible instability and conservative treatment results are uncertain.
• "Can I still lift weights with carpal instability?"Lifting weights with carpal instability can be challenging and may depend on the severity and type of instability, as well as the specific exercises performed. Since carpal instability involves a loss of normal wrist ability to transfer loads without abrupt changes of stress, heavy lifting can potentially exacerbate symptoms or increase the risk of further injury or progression of instability. Activity modification to avoid heavy gripping and repetitive hyperextension is generally recommended. The use of protective gear like wrist supports or taping might provide some stability during weightlifting, but this should be discussed with a healthcare professional. A consistent program of forearm and grip strengthening exercises, as part of physiotherapy, can help provide dynamic stability to the wrist and may improve tolerance for some level of weightlifting. It is crucial to listen to your body and avoid any movements that cause pain or a sensation of "giving way" . Consulting with a physiotherapist or hand specialist is recommended to determine safe and appropriate activities based on your individual condition.

Regain Wrist Confidence – Book a Hand Therapy Assessment Today

Carpal instability physiotherapy in Vaughan, North York, Toronto.

In the context of scapholunate dissociation rehab, the management depends on the stage of injury.

• For dynamic instability or scapholunate dissociation with a repairable SLIL, treatment often involves direct scapholunate repair for coronal plane instability and a dorsal capsulodesis to address sagittal plane instability and scaphoid malrotation. These repairs may be temporarily supplemented by K-wires. Rehabilitation after such surgery would focus on regaining range of motion, reducing pain and swelling, and then progressing to strengthening exercises for the forearm and grip, similar to the consistent strength routines we discussed for preventing recurrent instability. The goal would be to restore normal carpal kinematics and a stable grip.
• In cases where surgery involves a dorsal capsulodesis, such as the Blatt technique or a modified DIC ligament technique, postoperative rehab needs to consider potential limitations in wrist flexion. The aim is to achieve a stable wrist while maximizing functional range of motion and grip strength.

Your symptoms of wrist clicks and unstable grip are consistent with potential carpal instability, and if this instability progresses or is not appropriately managed, it can lead to arthritis management becoming a primary concern. Untreated scapholunate instability can result in scapholunate advanced collapse (SLAC), a predictable pattern of degenerative changes in the wrist. In such cases, management might eventually involve salvage procedures like four-corner arthrodesis or proximal row carpectomy.

It is also worth noting that instability can arise as a complication of other wrist conditions or surgeries. For example, trapeziectomy for thumb osteoarthritis can disrupt the scaphotrapezium-trapezoidal (STT) ligament complex and may be associated with carpal collapse. This highlights the interconnectedness of carpal biomechanics and the potential for instability to manifest in various ways, affecting grip stability. While not directly "thumb sprain rehab," this illustrates how issues around the thumb base can impact overall wrist function.

Therefore, if you are experiencing these symptoms, it is important to seek a thorough clinical examination and appropriate imaging to determine the underlying cause and guide management, which may include specific rehabilitation protocols tailored to the identified instability pattern.

Our Specialized Approach to Carpal Instability Rehab

Our programs include:

• Biomechanical analysis of wrist/forearm alignment
• Custom splinting and activity modification plans
• Sensorimotor retraining for precise joint control
• Collaboration with hand surgeons for complex cases

Why Choose Our Clinic?

• Hand Therapy Certification: Expertise in ligament and tendon rehab.
• Advanced Modalities: Ultrasound, laser therapy, and joint mobilization.
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