Journal of Therapy 29 (2016) 146e153

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Journal of Hand Therapy

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JHT READ FOR CREDIT ARTICLE #418. Special Issue: Rehabilitation for scapholunate injury: Application of scientific and clinical evidence to practice

Aviva L. Wolff EdD a,*, Scott W. Wolfe MD b a Leon Root, MD Motion Analysis Laboratory, Hospital for Special Surgery, New York, NY, USA b Hand and Upper Extremity Service, Department of Orthopedic Surgery, Hospital for Special Surgery, New York, NY, USA article info abstract

Article history: In this article, the development of a rehabilitation approach is describe using scapholunate injury as a Received 4 January 2016 model. We demonstrate how scientific and clinical evidence is applied to a treatment paradigm and Received in revised form modified based on emerging evidence. Role of the scapholunate interosseous within the path- 16 March 2016 omechanics of the carpus, along with the progression of pathology, and specific rehabilitation algorithms Accepted 18 March 2016 tailored to the stage of injury. We review the recent and current evidence on the kinematics of wrist motion during functional activity, role of the muscles in providing dynamic stability of the carpus, and basic science Keywords: of proprioception. Key relevant findings in each of these inter-related areas are highlighted to demonstrate Scapholunate injury Scapholunate interosseous ligament how together they form the basis for current wrist rehabilitation. Finally, we make recommendations for fi Dart-thrower’s motion future research to further test the ef cacy of these approaches in improving functional outcomes. Rehabilitation Ó 2016 Hanley & Belfus, an imprint of Elsevier Inc. All rights reserved.

Introduction demonstrate how these inter-related areas form the basis for current wrist rehabilitation. Finally, recommendations for future The development of a rehabilitation approach for a specific research are made to further test the efficacy of these approaches in injury follows an iterative process. First, the impairment and improving functional outcomes. mechanism of injury must be clearly identified, defined, and understood. Next, treatment approaches are developed that are based on a thorough understanding of anatomy, biomechanics, Overview of scapholunate injury: Current understanding pathomechanics of the particular injury, and prior scientific and clinical studies. Finally, these interventions are tested for efficacy in Carpal anatomy and biomechanics a clinical setting with the ultimate goal of improving function. This final step is critical to confirm the value and efficacy of an inter- An understanding of wrist biomechanics is required to appre- vention in achieving its desired outcome. This article demonstrates ciate the role of the scapholunate (SL) in overall carpal how scientific and clinical evidence is applied to a treatment function. The wrist joint comprises complex articulations between paradigm and modified based on emerging evidence. The role of the 5 metacarpals, the 8 carpal bones, and the . The carpus the scapholunate interosseous ligament (SLIL) is described within has been traditionally conceptualized as a dual linkage system of the context of carpal pathomechanics, followed by an explanation either rows or columns.1 The bones in the distal row (trapezium, of the progression of pathology. The article reviews the recent and trapezoid, capitate, and hamate) are bound tightly together current evidence on the kinematics of wrist motion during through strong intercarpal that allow for minimal functional activity, role of the muscles in providing dynamic motion between the bones. The bones in the proximal row stability of the carpus, and basic science of proprioception. In each (scaphoid, lunate, and triquetrum) have been described as an section, the key relevant findings are highlighted with suggestions intercalated segment due to their synchronized motion despite the and descriptions for specific rehabilitation applications to lack of direct tendon insertion.1-3 Carpal motion is relative to wrist motion; therefore, the scaphoid, lunate, and triquetrum rotate as a unit in flexion or extension depending on the direction of wrist * Corresponding author. Motion Analysis Laboratory, Department of Rehabilita- movement. With wrist flexion and radial deviation, the proximal tion, Hospital for Special Surgery, 535 East 70th Street, New York, NY 10021, USA. fl Tel.: þ1 212 606 1215; fax: þ1 212 774 7859. carpal row exes, and with ulnar deviation and extension, the 4 E-mail address: [email protected] (A.L. Wolff). proximal carpal bones extend. Carpal kinematics depends on

0894-1130/$ e see front matter Ó 2016 Hanley & Belfus, an imprint of Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jht.2016.03.010 A.L. Wolff, S.W. Wolfe / Journal of Hand Therapy 29 (2016) 146e153 147 the mechanical proprioceptive signals from the surrounding degenerative changes. Acutely, SLIL disruption may be treated with articulations that are transmitted via a complex ligamentous a primary repair of the ligament. These injuries, however, often are system.5 When this system is disrupted, instability ensues through undiagnosed and progress to require salvage procedures such as a changes in individual carpal bone motion and load transmission, proximal row carpectomy (PRC) and a range of intercarpal fusions. which leads to pain and loss of function. SL joint stability The degree to which carpal kinematics can effectively be restored depends on the contribution of 4 factors: intact articular surfaces, depends largely on the timing of the intervention and degree of ligamentous congruity, muscle contractions that provide joint degenerative change. At all times, the goal of surgery and compressive forces, and neuromuscular/proprioceptive control of rehabilitation is to maintain optimal mechanics, protect stability, the .1,6,7 and restore function and mobility.

The role of the SLIL in carpal function Wrist kinematics, dynamic stability, and proprioception: Implications for SLIL rehabilitation The SLIL is the primary stabilizer of the SL joint. It is a c-shaped ligament (Fig. 1) that attaches along the dorsal, proximal, and volar Functional kinematics of the wrist margins of the articulating surfaces. It has been divided anatomi- cally and histologically into 3 subdivisions: dorsal, membranous, A fundamental understanding of carpal kinematics is essential and volar.8,9 The dorsal component is the strongest and most and integral to early rehabilitation of SL reconstruction so that critical to SL joint stability and acts as a primary restraint to joint motion can be minimized at the injured or repaired sites and separation in wrist flexion and extension. The considerably weaker directed along a safe plane of movement. A recent review of volar ligament is important in controlling rotational stability. The functional wrist kinematics by Rainbow et al14 describes the intermediate membranous portion is of little consequence historical progression of measurement techniques for carpal mechanically. The SLIL is also richly innervated and provides critical kinematics with related findings. The following section highlights proprioceptive input for dynamic wrist stability.10,11 Additional and expands on those studies that have direct clinical relevance for stability is provided to the SL joint through secondary stabilizers, in the development of rehabilitation interventions. particular the scaphotrapezialtrapezoidal, radioscaphocapitate, and dorsal intercarpal ligaments. In the intact wrist, the posture of the Coupled wrist motion lunate is controlled by the flexion and extension moments applied Dart-thrower’s motion. An important and relevant premise is that through the scaphoid and triquetrum, respectively.12 SLIL injury functional wrist motion occurs along coupled paths of motion and disrupts this balance and sets off a chain of events beginning with not in pure planes of flexion/extension and radial/ulnar deviation. changes in force transmission and kinematics across the SL joint. Coupled wrist motion, defined as a composite motion of flexion/ Complete disruption of the SLIL and subsequent loss of distal extension and radial/ulnar deviation, has been studied in vivo and support at the scaphotrapezialtrapezoidal joint leads to pathologic in vitro in terms of both macro (global wrist) and micro (individual extension of the lunate, otherwise known as dorsal intercalated carpal) kinematics. Examples of coupled wrist motion include dart- segment instability.13 Over time, untreated SLIL disruption leads to thrower’s motion (DTM) and circumduction, and are explained in progressive scapholunate advanced collapse arthritis with detail below. DTM was first described by Palmer et al,15 has been accompanying pain and impaired function. Surgery to address the studied extensively.16-22 spectrum of SL and radiocarpal injury includes a range of pro- Motion of scaphoid and lunate in DTM plane. Early 3- cedures that effectively decrease pain and prevent further dimensional studies of carpal bone motion in intact

Fig. 1. The scapholunate interosseous ligament (SLIL) viewed from the proximal/radial side with the scaphoid removed. 148 A.L. Wolff, S.W. Wolfe / Journal of Hand Therapy 29 (2016) 146e153 found that as the wrist moved from a path of radialeextension to interplay between the bones, ligaments, articulating surfaces, ulnareflexion, the scaphoid and lunate exhibited minimal rota- muscles acting on the wrist, and the nerves that conduct impulses tion, despite a large range of wrist motion.16,17,19,23 A computed between the ligaments and the muscles.29 tomography study by Crisco et al19 demonstrated that the The aforementioned studies provide strong biomechanical evi- scaphoid and lunate approached 0 of motion in a pure DTM plane dence for rehabilitation protocols that minimize motion between of 1:1 coupling ratio of flexion/extension to radial/ulnar deviation. the scaphoid and lunate after surgical procedures on the proximal DTM occurs primarily at the , whereas the carpal row.17-19,30 Gentle DTM within a protected range is widely scaphoid and lunate are relatively motionless. In contrast, during believed to be safe for postoperative radiocarpal surgeries, as stress uniplanar motions of wrist flexion/extension and ulnar deviation, to the SLIL is minimal during this motion.31 Rehabilitation both the scaphoid and lunate exhibited significantly more approaches have been developed and proposed based on the movement. In addition, Crisco et al24 demonstrated that the me- understanding of these biomechanical studies.14,32,33 Various chanical axis of the wrist is oriented obliquely along the DTM custom-designed orthoses have been proposed for early post- plane to the anatomic axis. These studies provided the rationale operative stage used to limit wrist motion to a DTM plane and thus for incorporating the DTM path in early rehabilitation after repair minimize stress to the SLIL and motion to the lunate and scaphoid. of SL structures to protect healing structures while initiating early These are described in detail along with instructions for fabrication motion. However, it is still unknown how the orientation and and use.32,34,35 The basic premise in the early postoperative stage is coupling ratio varies between individual patients, and how to provide stability to the SL joint by limiting its motion through use clinically relevant this variation may be. In addition, Garcia-Elias of a protective splint. It is important to note that the ideal DTM path et al25 recently demonstrated in a 4-dimensional computed may be patient specific, and the ideal ratio has not been identified tomography study that SL joint movement was only minimal in clinical studies. Designed the DTM with a twist splint that can be when DTM was performed in healthy wrists with an intact SLIL. In adjusted to further limit range within the DTM plane during the subjects with SL disruption, DTM in fact created a greater acute postoperative period.35 In light of recent findings by Garcia- widening of the joint.25 Although this finding questions the Elias et al,25 only a small range in the radial/extension plane is current practice of SLIL rehabilitation in a DTM plane, this study recommended in the early post-SL repair period. Exercises and was conducted on a small number of subjects (n ¼ 6) and did not functional activities that use coupled motion along the DTM (ie, toy specify where along the path of motion the widening occurred. It hammer, mini darts) are performed in a limited plane by activating is important to note that no data exist on the kinematics of the the extensor carpi radialis longus (ECRL) and extensor carpi radialis proximal carpal row after SLIL repair or reconstruction. A study brevis (ECRB) to apply controlled load.14 In the presence of acute SL that quantifies the carpal kinematics and stress applied to a injury, the motion should be limited to the radial/extension portion healing SLIL after repair can provide conclusive evidence to of the DTM plane to avoid tension to the extensor carpi ulnarus support the proper use of a safer DTM range of motion for these (ECU) and increase gapping at the SL joint.29,36 It is important to injuries. keep in mind that studies of carpal bone motion in the DTM plane DTM: Impact on functional activities. Incorporating DTM into have not been conducted after SLIL reconstruction and therefore, rehabilitation is intuitive because this path of motion is com- caution is recommended, particularly after a recently repaired moninballisticmovement(throwing), occupational activities ligament.25 Findings by Garcia-Elias et al25 suggest that the (hammering), and household tasks (pouring).15,26,27 In strength of the repair and stability of the joint to withstand comparing kinematic coupling during 7 activities in a free and controlled DTM must be considered before implementation. restricted condition, the degree of coupling and kinematic path length (the total angular distance traveled by the wrist) were Circumduction envelope: An alternate parameter for evaluation and quantified during 7 occupational and daily activities and treatment. Another example of wrist coupled motion is wrist cir- demonstrated how each task had different requirements for cumduction. Wrist circumduction is accomplished by performing each parameter. Furthermore, when motion was artificially an elliptical movement that combines the position of the wrist in all restricted with use of a splint that reduced radial/ulnar devia- directions. The circumduction envelope is the 3-dimensional space tion, the motion requirements of the task were reduced, and that is generated by this motion. This parameter is emerging as functional performance was adversely affected.26 Because the another important indicator of wrist function as it provides degree of available coupling during tasks depends on midcarpal important information about the dynamic range of wrist motion motion, and different tasks require different degrees of during functional tasks.37 The orientation of the circumduction coupling, rehabilitation should consider specifictaskre- envelope along the principle longitudinal axis is aligned along the quirements when aiming to restore and maintain midcarpal DTM plane.24 Decreased circumduction envelope has recently been movement. It is not only the amount of motion required for task related to performance and functional ability in cohorts of subjects performance that is important but also the path of motion. A with simulated wrist injury.38,39 In comparing the circumduction subsequent study further evaluated the relationship between envelope between 2 surgical cohorts (PRC and 4-corner fusion), the path of motion, coupling, and task performance in a cohort Singh et al found that although overall circumduction area was of patients after PRC and midcarpal arthrodesis surgery and limited by both procedures, the location and orientation of the demonstrated that surgery alters both wrist kinematic param- preserved motion differed. The PRC envelope of motion (although eters and functional task performance.28 In that study, patients restricted) was more closely aligned along the plane of normal who underwent PRC surgery demonstrated greater wrist motion movement and the DTM path, whereas the 4-corner fusion enve- andimprovedperformancecompared with patients with mid- lope of motion was more limited in extension and ulnar deviation.40 carpal fusion. Thus, preservation of the midcarpal joint may Activities of daily living are performed in specificarcsof allow for better wrist function by preserving the DTM path and motion,41 and their related coupled paths of motion fall in is an important consideration in surgical selection and planning. task-specific areas of the circumduction envelope (Fig. 2).39 When Clinical implications: Early protected DTM after SL injury. the circumduction envelope is limited, the required coupling and The overall goal of rehabilitation of SL injury is to protect healing path lengths of specific tasks (dart throwing, hammering, and and injured structures and promote stability while maintaining winding a spool of thread) have been shown to fall outside the mobility to ultimately improve function. A stable wrist requires available envelope of wrist motion.39 Thus, the degree of restricted A.L. Wolff, S.W. Wolfe / Journal of Hand Therapy 29 (2016) 146e153 149 circumduction and differences in related performance are been described as SL-unfriendly structures,29 with the ECU important considerations for treatment selection. exhibiting the strongest pronator force on the proximal and distal Clinical implications. An understanding of the kinematic re- carpal rows, further contributing to widening of the SL space36 in a quirements of individual tasks is essential for selection of appropriate ligament-deficient joint. surgical interventions. Although kinematic parameters have been quantified for selected tasks,22-24 further studies are required to Clinical implications: Dynamic stability quantify kinematic parameters for common everyday tasks. A Garcia-Elias et al recommend a selective muscle reeducation comprehensive preoperative evaluation might include use of the program in the presence of SL instability with activation of the Canadian Occupational Performance Measure42 to identify tasks or SL-friendly structures, radial wrist extensors and FCU, and activities that are important to patients and are difficult or impossible inhibition of the ECU. It is not a coincidence that these are the to perform before treatment. The preoperative discussion would then muscles responsible for DTM. According to Garcia-Elias et al,25 include the impact of selected procedures on specific function to align when there is a complete dissociation of the SL joint, the expectations for postoperative function. Postoperatively, the reha- scaphoid no longer acts as a proximal row bone but rather as a bilitation focus is on maximizing the circumduction envelope and distal bone.25 Therefore, the recommended muscle strengthening coupled motion path required for task performance. This includes a exercise for SL dissociation is an isometric co-contraction of the focus on activities and exercises that challenge the extremes of wrist ECRL/APL muscles and flexor carpi radialis because these muscles motion, such as use of a wrist maze exerciser, wrist wand, and baton act to supinate the scaphoid, thus minimizing the gap. (Fig. 3).

Basic science of wrist proprioception The role of muscles in carpal stability Proprioception of the wrist has recently been proposed as a key The oblique location of the wrist muscle insertions of the ECRL, factor in providing dynamic stability to the carpal joints.7,29,33,43 ECRB, and flexor carpi ulnarus (FCU) is oriented along the DTM Proprioception is defined as the sensory process that provides plane.32 These muscles have the largest cross-sectional area in the both conscious and unconscious sense of joint position and joint forearm, guide DTM, and stabilize the SL joint.20 Garcia-Elias movement (kinesthesia).7 A complementary term, sensorimotor describes a kinetic theory of carpal stability in which lunate system, is also used frequently to describe the integration and posture is maintained by an equal balance of opposite flexion and processing of sensory and motor inputs in providing joint stability.7 extension forces that act on the carpus.12 Multiple resection studies As a richly innervated ligament, the SLIL plays an important role in have been performed to determine the effect of specific muscles on contributing to the proprioceptive mechanism that may be capable SL joint stability.31,36 The FCU, abductor pollicis brevis, ECRL, and of providing essential neuromuscular control and dynamic stability ECRB have been described as SL-friendly structures as they tend to to the wrist joint. The innervation patterns of the SLIL have been supinate the scaphoid, stabilize the SL joint, and thus further studied extensively, and the dorsal ligament in particular has been protect the SLIL. Conversely, the flexor carpi radialis and ECU have found to have an abundance of mechanoreceptors in these

Fig. 2. (Left) Wrist circumduction envelope in 3 conditions: unconstrained (green), semiconstrained (red), and constrained (blue). (Right) Kinematic path length for specific tasks; winding (black), hammering (red), and dart throwing (blue) within the unconstrained circumduction. Note: How the kinematic path length for specific tasks falls outside the circumduction envelope of the restricted conditions. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.) 150 A.L. Wolff, S.W. Wolfe / Journal of Hand Therapy 29 (2016) 146e153

Fig. 4. Isometric contraction of radial wrist muscles for dynamic stability of scapholunate joint.

Clinical implications: Proprioceptive and neuromuscular joint control Hagert33 suggests a detailed treatment approach for re-establishment of neuromuscular control after wrist injury or surgery that can be incorporated into an overall treatment Fig. 3. Wrist maze exerciser to encourage extremes for wrist motion. program. Specifically, rehabilitation strategies commonly used for ,46 knee,47 and ankle48 joint stability are suggested with modifications for the wrist. Six stages of treatment address ligamentomuscular reactions that originate from the anterior and impairment that targets both the unconscious and conscious posterior interosseous nerves.43,44 Hagert33 provides a thorough mechanisms of sensorimotor function based on basic science review of the basic science of proprioception and its application to studies of proprioception.33 Active joint position sense (JPS) mea- wrist rehabilitation. In brief, an appreciation of the mechanism by sures should be taken before treatment to establish a baseline of which the ligaments’ mechanoreptors communicate with the impairment level. JPS is a valid measure of proprioception and has surrounding muscles to stabilize the wrist is thought to be critical been used to report impairment in subjects after distal radius in re-establishing proper proprioception and muscle control after fracture.49 Proprioception training begins with basic propriocep- injury. On an unconscious level, the mechanoreceptors embedded tion awareness and JPS to promote conscious joint control is in the ligaments detect joint position change and transform these signals via afferent pathways to elicit spinal reflexes for increased efferent muscular input to augment joint stability. On a higher level, the central nervous system may be recruited for anticipatory planning and execution of voluntary joint control.33 For example, when the wrist moves from radial to ulnar deviation, the proximal carpal row moves from flexion to extension through a force couple generated by the unique helicoidal surface of the triquetrohamate joint.45 It is believed that this transition to extension is integrated into smooth carpal motion and function by the proprioceptive mechanoreceptor input of the dorsal radiocarpal ligament and intercarpal ligament complexes.7 Injury to key ligaments and subsequent prolonged immobilization may interfere with the proprioceptive pathway and further destabilize the carpus. Conversely, in the presence of ligament injury, when proprioceptive pathways are preserved, these investigators believe that muscle activation can play a role in the prevention of carpal subluxation and instability.29 The ability of muscle activation patterns to stabilize or widen the SL space during functional wrist motion has been demonstrated in cadaveric studies, leading to proposed specific activation patterns directed at preventing instability.29 It is important to recognize that these mechanisms are as yet incompletely understood, and clinical trials are underway. Fig. 5. Wrist stabilization exercises. A.L. Wolff, S.W. Wolfe / Journal of Hand Therapy 29 (2016) 146e153 151 encouraged via mirror training, visual occlusion exercises, and 12. Garcia-Elias M. The treatment of wrist instability. J Bone Joint Surg Br. e motor imagery.33 Care must be taken when implementing training 1997;79(4):684 690. 13. Gilford W, Bolton R, Lambrinudi C. The mechanism of the wrist joint. Guys Hosp techniques to avoid positions and ranges that can further stress an Rep. 1943;92:52e59. injured or recently repaired ligament. Once the ligament is 14. Rainbow MJ, Wolff AL, Crisco JJ, Wolfe SW. Functional kinematics of the wrist. e sufficiently healed, treatment is progressed to strengthen specific J Hand Surg Eur Vol. 2016;41(1):7 21. 15. Palmer AK, Werner FW, Murphy D, Glisson R. Functional wrist motion: a muscles to promote joint stability via isokinetic, isometric, and biomechanical study. J Hand Surg Am. 1985;10:39e46. eccentric exercises. Isometric exercise of the muscles can be 16. Moritomo H, Apergis EP, Herzberg G, Werner FW, Wolfe SW, Garcia-Elias M. accomplished by encouraging co-contraction while maintaining 2007 IFSSH Committee Report of Wrist Biomechanics Committee: biome- chanics of the so-called dart-throwing motion of the wrist. J Hand Surg Am. the wrist in a neutral position and gripping a FlexBar (The Hygenic 2007;32:1447e1453. Corporation, Akron, OH) (Fig. 4). 17. Werner FW, Green JK, Short WH, Masaoka S. Scaphoid and lunate motion Joint stabilization exercise can include tossing and catching a during a wrist dart throw motion. J Hand Surg Am. 2004;29(3):418e422. 18. Werner FW, Short WH, Green JK. Changes in patterns of scaphoid and lunate small ball while maintaining the wrist in a static position and motion during functional arcs of wrist motion induced by ligament division. bouncing a tennis ball on a racket. In the final stages, in the J Hand Surg Am. 2005;30:1156e1160. presence of a fully healed ligament and stable joint, therapy is 19. Crisco JJ, Coburn JC, Moore DC, Akelman E, Weiss A-PC, Wolfe SW. In vivo ’ progressed to target the unconscious muscular control and includes radiocarpal kinematics and the dart thrower s motion. J Bone Joint Surg Am. 2005;87(12):2729e2740. 50 reactive muscle activation, oscillatory devices such as the 20. Rohde RS, Crisco JJ, Wolfe SW. The advantage of throwing the first stone: how PowerBall (NSD Powerball, RPM Sports, Tipperary, Ireland) and understanding the evolutionary demands of Homo sapiens is helping us un- e Bodyblade (Mad Dogg Athletics, Venice, CA) (Fig. 5) and perturba- derstand carpal motion. J Am Acad Orthop Surg. 2010;18(1):51 58. 21. Moritomo H, Apergis EP, Garcia-Elias M, Werner FW, Wolfe SW. International tion exercises (plyometrics). It is important to note that although Federation of Societies for Surgery of the Hand 2013 Committee’s report on these interventions have been proposed based on the under- wrist dart-throwing motion. J Hand Surg Am. 2014;39(7):1433e1439. standing of basic science mechanisms, the efficacy of these 22. Short WH, Werner FW, Fortino MD, Mann KA. Analysis of the kinematics of the scaphoid and lunate in the intact wrist joint. Hand Clin. 1997;13(1): approaches on improving joint stability after SL injury has not 93e108. been validated clinically. 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42. Law M, Baptiste S, McColl M, Opzoomer A, Polatajko H, Pollock N. The Canadian 47. Desnica Bakrac N. Dynamics of muscle strength improvement during isokinetic occupational performance measure: an outcome measure for occupational rehabilitation of athletes with ACL rupture and chondromalacia patellae. therapy. Can J Occup Ther. 1990;57(2):82e87. J Sports Med Phys Fitness. 2003;43(1):69e74. 43. Hagert E, Persson JKE, Werner M, Ljung B-O. Evidence of wrist proprioceptive 48. Sekir U, Yildiz Y, Hazneci B, Ors F, Aydin T. Effect of isokinetic training reflexes elicited after stimulation of the scapholunate interosseous ligament. on strength, functionality and proprioception in athletes with functional ankle J Hand Surg Am. 2009;34(4):642e651. instability. Knee Surg Sports Traumatol Arthrosc. 2007;15(5):654e664. 44. Vekris MD, Mataliotakis GI, Beris AE. The scapholunate interosseous ligament 49. Karagiannopoulos C, Sitler M, Michlovitz S, Tierney R. A descriptive study on afferent proprioceptive pathway: a human in vivo experimental study. J Hand wrist and hand sensori-motor impairment and function following distal radius Surg Am. 2011;36(1):37e46. fracture intervention. J Hand Ther. 2013;26(3):204e214; quiz 215. 45. Weber ER. Concepts governing the rotational shift of the intercalated segment 50. Balan SA, Garcia-Elias M. Utility of the Powerball in the invigoration of the of the carpus. Orthop Clin North Am. 1984;15(2):193e207. musculature of the forearm. Hand Surg. 2008;13(2):79e83. 46. Myers JB, Wassinger CA, Lephart SM. Sensorimotor contribution to 51. Hincapie OL, Elkins JS, Vasquez-Welsh L. Proprioception re-training for a pa- shoulder stability: effect of injury and rehabilitation. Man Ther. 2006;11(3): tient with chronic wrist pain secondary to ligament injury with no structural 197e201. instability. J Hand Ther. 2016;29(2):174e181. A.L. Wolff, S.W. Wolfe / Journal of Hand Therapy 29 (2016) 146e153 153

JHT Read for Credit Quiz: #418

Record your answers on the Return Answer Form found on the c. neuromuscular proprioceptive contributions tear-out coupon at the back of this issue or to complete online d. all of the above and use a credit card, go to JHTReadforCredit.com. There is #4. Citing the important work of Garcia-Elias the suggest early ex- only one best answer for each question. ercise following S-L ligament repair should be a. limited to isometric exercises of the ECRL and ECRB #1. The primary stabilizer of the S-L joint is the b. active ROM throughout the entire arc of the DTM a. dorsal S-L ligament c. a small range in the radial-extension plane b. volar S-L ligament d. a small range in the traditional flexion-extension plane c. SLIL complex #5. The FCU, ECRB, and ECRL are oriented along the plane of the d. dorsal capsular ligament DTM #2. An example of coupled motion in the wrist is a. false a. circumduction b. true b. partial pronation-supination c. manual A-P gliding of the midcarpal joint When submitting to the HTCC for re-certification, please batch your d. controlled TFCC shearing JHT RFC certificates in groups of 3 or more to get full credit. #3. Stability of the S-L joint is dependent upon a. specific muscle contractions b. ligamentous congruity