The goal of rehabilitation of the wrist after ligament injury or with instability is a symptom-free, stable wrist that is capable of withstanding the forces involved in activities of daily living (ADLs).
Efforts to restore mobility after injury and healing should be guided more by the individual’s functional requirements than by arbitrary range of motion (ROM) goals that approach what is considered normal ROM.
The foundation for a wrist rehabilitation program is a thorough assessment and definitive diagnosis; ligament injury or instability could progress over time if undiagnosed and/or improperly treated.
The emerging understanding of wrist biomechanics and dart thrower’s motion, wrist mechanoreceptors and ligamentomuscular reflexes, proprioception reeducation, and specific muscle loading and carpal alignment is the foundation upon which a new approach may be developed for rehabilitation of the unstable wrist.
The partnership of hand surgeons, therapists, researchers, and clinicians is essential in the continued development and validation of an effective approach to treating carpal instability.
* The author wishes to acknowledge editorial input from Paul LaStayo and Susan Blackmore.Rehabilitation of the wrist after carpal ligament injury or with instability is based on consideration of the nature of the injury or onset; the specific ligament(s) involved; the stage of symptom response, resolution and/or tissue healing; the nature of any surgical procedures, whether reparative or salvage; and any resultant secondary changes or alteration in the biomechanics and/or load-bearing capacity of the wrist. Added to these considerations are the patient’s functional requirements and habits related to work, self-care, leisure, and family and household responsibilities and whether these have factored into the development of or have been adversely affected by the wrist condition.
The goal of rehabilitation of the wrist after ligament injury or with instability is a symptom-free, stable wrist that is capable of withstanding the forces involved in the activities that the patient needs to perform for his or her work or for leisure and other ADLs. Regarding wrist ROM, efforts to restore mobility after injury and healing should be guided more by the individual’s functional requirements than by arbitrary ROM goals that approach what is considered normal ROM. Relevant to this approach are the studies of functional ROM that were published more than 20 years ago that illustrate that the wrist ROM required to perform most ADLs is less than what is considered normal ROM. , For example, Palmer and colleagues, in a study evaluating wrist motion used by normal subjects in the performance of standardized tasks, found that functional wrist ROM is between 5 degrees of flexion and 30 degrees of extension, 10 degrees of radial deviation, and 15 degrees of ulnar deviation. Ryu and colleagues, in a similar study, found that wrist motion of 40 degrees of extension and 40 degrees of flexion with 40 degrees of combined radial and ulnar deviation is required for most ADLs.
Furthermore, in their study, Palmer and colleagues described a “dart thrower’s motion” (DTM) pattern (i.e., wrist extension/radial deviation to flexion/ulnar deviation) that was used to perform many of the tasks. More recently, this pattern of motion has been the subject of intense study and has been suggested as having a potential role in the early postoperative rehabilitation after specific surgical procedures or for rehabilitation after a period of immobilization for nonoperative management of minor wrist ligament injuries. The DTM is discussed further in a later section.
Throughout the rehabilitation program, the therapist must closely monitor and use the patient’s symptom response to therapy as an indicator of the capacity of the wrist to handle load. The “no pain, no gain” philosophy has no place in the rehabilitation program. It is important to keep in mind that many of the provocative maneuvers used to detect carpal instabilities are performed with motion combined with load (see Chapter 7 ) and that rehabilitation exercises that involve ROM with load (e.g., wrist curls with free weights) may trigger symptoms and potentially undermine the stability of the wrist. In general, it is advisable to avoid aggressive stretching and repetitive wrist ROM exercises and generic wrist strengthening in the rehabilitation of wrist instability and wrist ligament injuries.
General goals of rehabilitation after operative or nonoperative management of wrist ligament injuries and of symptomatic ligament laxity include the following:
Control of edema and pain
Maintenance of the ROM of uninvolved joints
Achievement of functional motion of the wrist when healing permits
Preservation of wrist stability
Avoidance of activity and exercise that adversely load the wrist and undermine recovery of function/healing
Return to previous level of function when healing permits
Prosser and colleagues conducted a survey of 85 Australian Hand Therapy Association members to determine the current practice of the diagnosis and treatment of carpal instability. The most commonly used tests for wrist examination were the scaphoid shift test (radial stress, Watson test), the lunotriquetral (LT) ballottement test, and stress tests for the triangular fibrocartilage complex and the midcarpal joint. The most used treatments were patient education (advice and activity modification), custom and prefabricated wrist orthoses, and isometric exercises of the wrist musculature.
Similar published surveys reflecting practice patterns among other therapists in other regions as well as published studies of wrist rehabilitation for carpal instability and carpal ligament injuries have been limited or lacking. Chapters in textbooks describe rehabilitation programs based on author experience and for the most part are consistent with the practice patterns reported by Prosser. More specific exercise approaches and orthoses are sporadically discussed in relation to specific patterns of carpal instability (e.g., dynamic muscle stabilization and pisiform boost orthoses for palmar midcarpal instability [MCI]). Some of these are described in the following sections. Postoperative guidelines and rehabilitation are inconsistently included in published articles regarding various surgical procedures for wrist ligament injuries or instability patterns and are typically limited to general timelines for immobilization, orthosis use, and activity restrictions. It is important to note that although there may be some consensus among clinicians in their current practice approach for carpal instability, this has not been established as best practice. Only after clinical research studies are conducted and published will current practice be confirmed or ruled out as best practice. Until this time, clinicians should observe established timetables for tissue healing in the decision making regarding duration of immobilization, introduction of protected motion, application of gentle loading, and finally return to functional activities after carpal ligament injuries and surgery.
Emerging Concepts and Strategies
Intriguing concepts and strategies are emerging in relation to rehabilitation for carpal instability and carpal ligament injury; this is an area ripe for further exploration, development, and research. DTM, wrist mechanoreceptors and ligamentomuscular reflexes; proprioception reeducation; and specific muscle loading and carpal alignment are areas of recent study with potential application to rehabilitation for wrist instability and wrist ligament injury and are discussed in the following section.
Dart Thrower’s Motion
As mentioned previously, Palmer and colleagues in 1985, using an electrogoniometer, evaluated the wrist motion involved in the performance of a representative sample of ADLs. They found that most tasks were performed in a plane from 40 degrees of extension and 20 degrees radial deviation to 0 degrees flexion and 20 degrees ulnar deviation. They called this pattern the dart thrower’s motion (DTM) ( Fig. 75-1 ). More recent biomechanical studies of this pattern of motion reveal that it uses the midcarpal joint and radiocarpal motion is minimized. Scapholunate (SL) interosseous ligament (SLIL) elongation has been found to be minimal along the dart thrower’s path, and scaphoid and lunate motion was found to be significantly less than in any other direction of wrist motion. Werner and associates , examined nine different variations of a wrist DTM to determine more precisely the specific DTM pattern that minimized scaphoid and lunate motion. They found certain intermediate dart-throwing patterns that required minimal scaphoid and lunate motion. Crisco and associates identified a DTM pattern approximately 45 degrees from the sagittal plane as a wrist motion during which scaphoid motion approached 0 degrees and a plane approximately 30 degrees from sagittal in which there is minimal lunate motion. The implication for rehabilitation is that protocols could be developed using the DTM as a means of early motion of the wrist after fractures, SLIL injuries, and repairs or reconstructive procedures involving the scaphoid and lunate. The specific plane of DTM chosen would depend on the individual and which bone needs the least motion or which ligament needs to be protected from elongation. The protocol would need to restrict the early motion of the wrist to the specific dart-throwing pattern chosen. Orthoses could be designed to constrain the wrist motion along the specific DTM path ( Fig. 75-2 ). More study is needed to determine the optimal time to introduce the DTM after surgery or injury; how long to restrict motion along the DTM path; the specific DTM pattern best for specific individuals, injuries, and procedures; and long-term outcomes.
Wrist Ligament Mechanoreceptors and Ligamentomuscular Reflexes
Wrist stability requires intact ligaments that serve not only a passive mechanical function to constrain and maintain carpal relationships but also, as current research reveals, a sensory function to convey afferent information that is believed to play a role in dynamic stabilization of the wrist. The sensory function of wrist ligaments is believed to be served by mechanoreceptors that are specialized neural end organs that function as biologic transducers conveying a physical stimulus into a neural signal. The central nervous system interprets these afferent impulses as position sense, motion threshold, velocity, pressure, or pain—in other words, proprioceptive function. Tomita and colleagues, in a cadaver study, described the shape and distribution characteristics of a large number of nerve endings and mechanoreceptors in the dorsal radiocarpal ligament and found consistent concentrations of these nerve endings in the superficial, proximal, and distal regions of the ligament, a pattern of nerve ending distribution consistent with ligament strain. Hagert and colleagues , examined differences in the structural composition and presence of mechanoreceptors and nerve structures among wrist ligaments and found variation in composition and innervation of the wrist ligaments studied. They proposed that the difference in innervation might reflect differential function with those ligaments without innervation serving a mechanically important function and those with rich innervation serving a sensory important proprioceptive function. The mechanically important ligaments were located in the radial force-bearing column of the wrist, whereas the sensory important ligaments were related to the triquetrum. Hagert and colleagues concluded that the triquetrum and its ligamentous attachments should be regarded as key elements in the generation of proprioceptive information necessary for adequate neuromuscular wrist control. Very recently, Hagert and colleagues presented evidence of a wrist ligamentomuscular reflex after stimulation of the SLIL. Using electrical stimulation of the SLIL, electromyographic activity was monitored in four muscles (flexor carpi radialis [FCR], flexor carpi ulnaris [FCU], extensor carpi radialis brevis [ECRB], and extensor carpi ulnaris [ECU]) for the purpose of investigating possible wrist ligamentomuscular connections. With the wrist in extension, stimulation of the SLIL produced an immediate response in the FCR and FCU. Within seconds, reciprocal activation of the ECRB and ECU occurred. After this a period of co-contraction was noted. With the wrist in flexion, stimulation of the SLIL caused a response in the ECRB, then reciprocal activation of the FCR and FCU. Hagert and colleagues interpreted this as a protective response of the antagonist muscle to impending injury and potentially damaging wrist positions, with subsequent co-contraction of agonist and antagonist providing dynamic stabilization of the wrist. The implications of these findings are significant and suggest that rehabilitation strategies could be developed that involve proprioception reeducation targeting specific muscles in the treatment of specific ligament injuries.
Retraining of proprioception is an established and accepted part of a rehabilitation program to improve the dynamic stability of the shoulder, ankle, and knee. Dynamic stability refers to the role of proprioception in regulating joint function. In the normal situation, ligament strain generates proprioceptive stimuli that trigger reflex changes in muscle contraction and balance to result in protection and stabilization of a joint. Ligament injury or insufficiency may distort proprioception and disrupt the function of the reflex mechanism and adversely affect dynamic joint stability. Prompted by the findings of wrist ligament mechanoreceptors and wrist ligamentomuscular reactions, the application of proprioception reeducation techniques has begun to be discussed in relation to the rehabilitation of wrist instability and wrist ligament injuries. Elisabet Hagert is leading the way with a proposed rehabilitation approach designed to restore the dynamic stability and function of the injured or unstable wrist. The foundation for her approach is her research described previously with identification of muscles that serve a protective function for specific ligaments and training of those muscles to respond more efficiently to prevent joint injury. Hagert stresses the importance of basic hand therapy principles as a foundation for the program, addressing swelling, pain, and limited motion first. After this, exercises to improve awareness of joint position and joint motion or kinesthesia are introduced. Examples include exercises that require the patient to actively duplicate a specific joint position or angle or to indicate when the wrist is passively moved to a predetermined position with vision and without. Hagert suggests the use of mirror therapy as a means of enhancing this training. For example, the patient can observe the reflected motion of the uninvolved wrist in a mirror placed on the opposite side, which creates an illusion of motion of the involved wrist. The visual input of the observed movement is intended to positively influence cortical areas involved in the sensorimotor control of the involved wrist with the goal of improved motor performance. The next stage involves neuromuscular rehabilitation with introduction of specific exercises for specific muscles based on and guided by the ligaments involved or on the pattern of instability. For example, based on studies of muscular response after stimulation of the SL ligament, Hagert and Garcia-Elias have identified the FCU, abductor pollicis longus (APL), and ECRL as SL “friendly” muscles (i.e., they serve a joint protective function). They advocate proprioception exercises for these muscles in the case of an SL injury and instability. Interestingly, these are the muscles responsible for the dart thrower’s pattern of motion. Much further research is needed to explore this intriguing aspect of wrist function.
Types of exercises include isometric, isokinetic, isotonic, eccentric, co-contraction or co-activation of agonist and antagonist muscles, and reactive muscle activation. These exercises have been discussed in relation to rehabilitation for shoulder, knee, and ankle instability. Hagert’s program describes them in relation to rehabilitation for wrist instability and after carpal ligament injury. Further study is needed to evaluate their efficacy and define parameters of their use when applied to the injured and unstable wrist.
Muscle Loading and Carpal Alignment
The effect of specific muscle loading on the alignment of the carpus and individual carpal bones is being studied by Garcia-Elias. He found that ECU contraction increases pronation of the scaphoid, which results in pulling or tightening of the SL ligament. This suggests that ECU activity would potentially stress an injured SL ligament or exacerbate SL instability. His finding correlates with Hagert’s finding of ECU inhibition with SL ligament stimulation. On the other hand, FCR, FCU, and APL activity causes scaphoid supination, resulting in relaxation of the SL ligament. Based on these findings, these muscles could be targeted in a proprioception reeducation program in the case of SL instability, and emphasis on ECU exercises should be avoided. The ECU is not the enemy in all cases of carpal ligament injury. For palmer MCI, Lichtman and associates identified the ECU as well as the FCU and hypothenar muscles as being important in providing dynamic muscle compression in the absence of adequate ligament support.
Another example of the effect of muscle loading on carpal alignment noted by Garcia-Elias is the isometric contraction of the FCU and hypothenar muscles, which generates a dorsally directed force onto the triquetrum via the pisiform. These muscles have been identified as important dynamic stabilizers in the case of lunotriquetral instability and MCI and may have the potential to be trained to provide neuromuscular control.
Many questions remain to be answered regarding the effects of specific muscle loading and the resulting effect on carpal bone alignment and the applicability of this information in a clinical situation. For example, with varying degrees of injury to a specific carpal ligament, does the effect of specific muscle loading on carpal alignment vary? What difference does the position of the forearm have on the specific muscle-loading effects? What about the combined muscle loading of agonist and antagonist on carpal alignment? Further study is needed to determine the answers to these questions and to determine clinical applications. In the meantime, their use in a clinical situation is intuitive, and results will need to be closely monitored.
Wrist Evaluation Procedures
The foundation for a wrist rehabilitation program is a thorough assessment. The components of the wrist assessment include a detailed history, visual inspection, objective measurements of ROM, strength and sensibility, palpation and provocative testing, a functional assessment, and administration of an outcome measure appropriate for the wrist such as MacDermid’s Patient Rated-Wrist Evaluation. If the patient has been referred to therapy from a nonspecialized practitioner with a vague diagnosis such as wrist pain or sprain, the clinical examination takes on even greater importance. In this instance, undiagnosed pathology may exist, therapy may not be indicated, and the patient may need to be referred to a hand surgeon for definitive diagnosis.
The history includes details pertaining to the onset of the problem, for example, when the problem started and whether the condition occurred as a result of a single traumatic event or whether it started gradually and worsened over time. It is important to find out what treatment has been provided, including surgical and nonsurgical management, and the efficacy of that treatment. This information will help in the treatment planning process by avoiding approaches that proved not to be helpful.
A careful exploration of the patient’s symptoms is included, for example, when they occur, whether in response to a specific activity or related to use in general, whether symptoms occur at rest, what relieves the symptoms, and what makes the symptoms worse. In some cases, it may be helpful to use a numeric pain rating or other type of pain measurement that establishes a baseline for later comparison when evaluating the patient’s response to therapy. The impact of the patient’s symptoms/condition on ADLs as well as work and leisure activities will be important to determine the degree of disability caused by the wrist problem. An ADL checklist or questionnaire and/or a self-report outcome measurement tool (see Chapter 16 ) can be used to document a baseline of functional performance and identify problem areas.
Visual inspection of the wrist and hand with comparison with the uninvolved side can give clues as to the nature and extent of the problem. Spontaneous use, wrist posture and alignment, nail and skin color and condition, signs of use or disuse, muscle bulk, and atrophy are all important to note.
A baseline of the patient’s status and function is established with specific measurements of active ROM (AROM) and passive ROM (PROM) of all planes of wrist motion, as well as of supination and pronation. Care must be taken when measuring PROM to stay within the patient’s comfort range and to avoid forceful end-range overpressure. In some cases, PROM measurements may be deferred at the initial evaluation depending on the patient’s pain level and healing status. A goniometer is used to ensure accuracy of measurement. The most reliable method for measuring wrist flexion and extension is with the goniometer placed on the dorsum of the wrist for flexion and on the volar aspect of the wrist for extension. Wrist ROM varies in the normal wrist; therefore, measurements of the uninvolved side should be taken for comparison.
Laxity of the wrist may be a trigger for chronic wrist pain, and this is difficult to localize and define. Objective methods of quantifying wrist laxity have been described. The Garcia-Elias method involves four clinical tests that include measurement of maximal wrist flexion and wrist extension and measurement of the distance of the thumb tip to the forearm with the thumb bent back to the forearm, first with the wrist in maximal extension and then in maximal flexion. The Beighton method involves five tests including hyperextension measurements of the elbow, knee, and small finger; a test of thumb laxity as described in the Garcia-Elias method; and the ability to place hands flat on the floor while maintaining knee extension.
The size of the wrist can be documented with circumference and volumetric measurements. For more acute conditions, the size of the wrist when compared with the uninvolved side may be larger, reflecting the presence of swelling, and with more chronic conditions, it may be smaller, reflecting disuse and loss of muscle bulk. Van Velze and colleagues found that the left nondominant side was 3.3% smaller than the dominant side with volume measurement in a study of 263 male laborers. The volumeter has been found to be reliable to within 1% of the total volume when one examiner performs the measurement.
Grip strength measurement is performed with the use of a dynamometer. In some instances, measurement of grip strength may be deferred. For example, in the case of the patient with an incompletely healed condition, referred after cast removal for early phase rehabilitation, grip testing would not be relevant and, if attempted, could potentially overstress the healing wrist. Guidelines for the recommended method of measurement have been published by the American Society of Hand Therapists. Regular calibration and maintenance of grip gauges is important to ensure accuracy and comparability of repeated measurements.
A sensibility screen is performed to help detect the presence of nerve compressions. The median, ulnar, and dorsal radial sensory nerve can be compressed or irritated with a wrist injury, and the cutaneous distribution of these nerves is examined. Semmes-Weinstein light touch threshold testing has been found to be the most sensitive clinical test for detecting nerve compression.
In those cases with a nonspecific diagnosis such as wrist pain and strain referred from a nonspecialized practitioner, a physical examination with palpation and provocative testing should be performed to identify the symptomatic regions and structures and to determine whether the patient should be referred to a hand surgeon for definitive diagnosis. Important for the performance of a physical examination is a thorough knowledge of surface anatomy and an understanding of the biomechanics and pathomechanics of the wrist and of the common conditions that may occur as a result of injury. Piecing together details from the history of the mechanism or onset of the injury or condition and correlating this information with the physical findings can help in the process of determining which structures may be involved. The provocative clinical tests are used to identify the clicks, clunks, snaps, and pops of the various instability patterns and conditions that can occur. Examples of provocative tests include the scaphoid shift test, also referred to as the Watson test, and the radial stress test used to assess scaphoid stability. The midcarpal shift test is performed to detect MCI and the LT ballottement test is used to detect LT instability. These are but a few of a plethora of clinical provocative maneuvers that have been described and are helpful in the evaluation of the painful wrist. See Chapter 7 for a detailed description of clinical tests and examination procedures for the wrist.
The importance of an accurate diagnosis cannot be overstated. Left undiagnosed and/or improperly treated, the ligament injury and wrist condition could progress over time to a more advanced stage of instability. Short and colleagues note that repetitive motion after ligament injury probably results in further carpal instability. If the therapist has any suspicion that more than a minor soft tissue strain has occurred or if the patient fails to improve after an initial brief trial of therapy, the patient should be referred to a specialist for further evaluation.