- Email: [email protected]
Dart-Splint: An innovative orthosis that can be integrated into a scapho-lunate and palmar midcarpal instability re-education protocol
Journal of Hand Therapy xxx (2015) 1e6
Contents lists available at ScienceDirect
Journal of Hand Therapy journal homepage: www.jhandtherapy.org
Practice Forum
Dart-Splint: An innovative orthosis that can be integrated into a scapho-lunate and palmar midcarpal instability re-education protocol Federica Braidotti PT a, b, *, Andrea Atzei MD a, Tracy Fairplay PT c, d a
Fenice Hand Surgery and Rehabilitation Team, Treviso Italy Fisiomano e Private Professional Upper Extremity Rehabilitation Center, Pordenone, Italy c Studio Fairplay e Private Professional Functional Rehabilitation of the Upper Extremity Clinic, Bologna, Italy d Hand Rehabilitation Unit, Policlinic, Modena, Italy b
The Authors describe a novel hinged orthosis that permits selective midcarpal mobilization along the plane of the dart throwing motion. This orthotic device can be used to assist rehabilitation protocols aimed to limit radiocarpal joint mobility and scapho-lunate ligament overload and to accelerate wrist functional recovery after ligamentous injuries around the proximal carpal row. e VICTORIA W. PRIGANC, PhD, OTR, CHT, CLT, Practice Forum Editor
Introduction Most activities of daily living (ADL) are performed using an oblique wrist motion. This movement proceeds from radial deviation-extension to ulnar deviation-flexion and has been called the dart thrower’s motion or the dart throwing motion (DTM).1 The DTM’s arc of movement is referred to as “the most stable and controllable plane of motion in a kinematic sense and represents the functional plane of wrist motion for occupational and vocational activities in which minimal wrist muscle force is used”.2 The concept of wrist movement along an oblique plane represents the actual evolution of carpal kinematics rather than the traditional concept that considered basic wrist movement running along the sagittal and coronal planes. A few centuries have passed since the time that carpal kinematics has been anatomically described by Vesalius in 1543,3 to the first complete study of carpal motion in cadaver wrists by Henke in 1859.4,5 He noted that the radiocarpal and midcarpal joints moved independently, with mutually perpendicular axes passing through the capitate. He therefore concluded that there was no “pure” motion in the joint and he was the first author to suggest
* Corresponding author. Viale Pasteur 6, Treviso 31100, Italy. Tel.: þ39 3478585715 (mobile); fax: þ39 0422698150. E-mail addresses: [email protected], federica.braidotti@fisiomano.com (F. Braidotti).
that wrist joint motion occurred around an oblique axis. Since this discovery, many publications and debates have been documented and have led to the publication of a report by IFSSH Committee Report of Wrist Biomechanics in 2007,1 which emphasizes the DTM from an anatomical, anthropological and biomechanical point of view. Kinematic review of dart throwing motion and rationale for the use of the Dart-Splint Before one begins to fabricate a Dart-Splint, it is of utmost importance to have a complete knowledge of wrist and more specifically midcarpal kinematics. The DTM takes place in the midcarpal joint and uses this joint to its maximum extent. This joint is an articular complex, in which the scaphotrapeziotrapezoid joint (STTJ)6 is the key joint that stabilizes and controls the DTM. The axis of the DTM plane runs obliquely from the radio-palmar aspect of the scaphoid tuberosity to the ulnodorsal aspect of the hamate7 (Fig. 1). The most interesting aspect is that the STTJ is a monoaxial joint, moving along a single axis that parallels with the plane of the DTM, whereas, the directions of motion of the Luno-Capitate and Triquetral-Hamate joints somewhat differ among wrist flexion-extension, radioulnar motion and DTM. The forearm muscles that are directly involved in generating the DTM are the Extensor Carpi Radialis Brevis and Longus (ECRL-B) and the Flexor Carpi Ulnaris (FCU). Looking at a transverse view of the wrist, one can note that the
0894-1130/$ e see front matter Ó 2015 Hanley & Belfus, an imprint of Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jht.2015.01.007
2
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
the majority of daily functional activities. With these purposes, the authors developed a special orthotic device in order to facilitate protected midcarpal motion and named it the “DartSplint”. The Dart-Splint allows oblique wrist motion along the DTM plane, thus inhibiting movement of the healing structures following surgery or injury around the PCR.
Materials used 1. 2. 3. 4. 5. 6.
2.4 mm thermoplastic (Orfit) Adhesive hook velcro Non-adhesive loop velcro Rivets Plast-O-Fit Soft padding
Fabrication procedure
Fig. 1. Schematic drawing showing the orientation of the axis of the DTM, which runs obliquely from the radio-palmar aspect of the scaphoid tuberosity to the ulno-dorsal aspect of the hamate.
oblique orientation of DTM plane goes along the same axis that links the ECRL-B and FCU (Fig. 2). As suggested by Garcia-Elias, and confirmed by several biomechanical studies, DTM is produced as an almost “isolated” midcarpal joint motion, with a minimal involvement of the radio-carpal joint (RCJ).8 The radiograms of the lateral view of the wrist taken at both ends of the DTM (extension/radial-deviation and flexion/ulnardeviation) show that the position of the lunate remains “almost” unchanged (Fig. 3), thus confirming minimal movement of the RCJ.9 In addition, as demonstrated by Upal and coworkers9 and further biomechanical studies,10e12 the tensile stresses of the dorsal insertions of the scafo-lunate interosseous ligament (SLIL) are minimized during DTM. According to these kinematic findings, selective midcarpal mobilization along the DTM may be used for specific rehabilitation protocols aimed to limit RCJ mobility and SLIL overload. Therefore, healing of injured or repaired tissues around the proximal carpal row (PCR) may not be disturbed during early DTM. An additional advantage is also gained by early recovery of the specific motion needed for
Fig. 2. In the transverse section of the wrist, the arrow shows that the axis of DTM goes along the same line joining its muscolar motors: Extensor Carpi Radialis Brevis and Longus (ECRL-B) and Flexor Carpi Ulnaris (FCU).
1. The first step is to underline the anatomical landmarks in order to guarantee a precise construction of the Dart-Splint. The palmar hinge should lie above the scaphoid tubercle (easily palpable) and the dorsal hinge should lie at the same level, along the line of the ring finger’s metacarpal (which approximates the ulno-dorsal aspect of the hamate) (Fig. 4). The landmarks for the dynamic junction are very important and should be aligned with the DTM axis in order to allow movement along the DTM plane; 2. The orthosis is made of two static thermoplastic components: a carpal unit and an anti-brachial unit (Fig. 5). Once the malleable thermoplastic has been removed from the heated water 60 F, mold the material over patient’s hand at the carpal level. Attention should be paid that the hole for the thumb is not too large, excluding the palmar landmark over the scaphoid tubercle where the palmar hinge must lie. The anti-brachial unit is positioned 2 cm inferior to the carpal unit’s proximal border, molding it around the palmar aspect of the forearm. Both thermoplastic units should be closed on the hand’s and forearm’s ulnar side. 3. Underline the landmarks over both carpal and anti-brachial units; 4. Roll and flatten the Plast-O-Fit onto itself and mold it in order to obtain two little perfectly straight connecting bars (about 2 cm width 6 cm length) (Fig. 6); 5. The 2 connecting bars are interposed between the 2 units in order to form 2 dynamic junctions: one palmar-radial side, the other on the dorso-ulnar side of the orthosis. On the carpal unit, the distal portion of one of the Plast-O-Fit bars should be attached with a rivet to the dorsal landmark, and the distal portion of the other bar to the palmar landmark; 6. Once both dorsal and palmar bars are riveted to the carpal unit, it is then necessary that the patient puts on both units. On each bar, measure a distance of 2e3 cm from the base of the carpal unit to the distal rim of the anti-brachial unit, then allow an additional length of minimum of 2 cm on the proximal extremity of the bar for fixation on the antibrachial unit. 7. Take the splint off the patient and carefully heat the last 2 cm of both bars and mold them simultaneously onto the anti-brachial unit making sure that the bars are perfectly aligned with the rivet, 0 of inclination. Pay attention and be careful to attach the bars straight and parallel to each other;
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
3
Fig. 3. The position of the lunate remains unchanged on the lateral view radiograms of the wrist taken at both ends of DTM. (A) Extension/radial-deviation (ERD); (B) flexion/ ulnar-deviation (FUD).
Fig. 4. Landmarks for hinge positioning are drawn on patient’s skin. (A) Palmar landmark lies over the scaphoid tubercle and (B) dorsal landmark on the line of ring finger’s metacarpal.
Fig. 5. Static thermoplastic components of the Dart-Splint: (A) carpal unit and (B) anti-brachial unit.
4
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
8. After a few minutes, when the bars are firmly attached, try to test the movement of the orthosis with your hands, before putting the orthosis back on the patient (Fig. 7). 9. When the movement of the orthosis is fluid and the rivets turn easily, the orthosis is put back on the patient that can try the dart throwing movement protected by the orthosis (Fig. 8). 10. To provide further comfort to the patient, the orthosis can be padded along its borders.
Dart-Splint e indications
Fig. 6. Two connecting bars are made of Plast-O-Fit.
The “Dart-Splint” may be utilized in post-operative rehabilitation protocols in which it is necessary to immobilize the RCJ, such as following surgical repair or reconstruction of radio-carpal ligaments, scapho-lunate ligaments, midcarpal instability and radioscafo-lunate fusion. In addition, the Dart-Splint can also be recommended for conservative treatment of several types of predynamic and dynamic SLIL instability and palmar midcarpal instability. In the above-mentioned conditions, use of the DartSplint may allow the therapist to anticipate the start of the rehabilitation program. For example, the period of immobilization after SLIL reconstruction using the Dart-Splint may be reduced by 2 weeks and controlled mobilization of the midcarpal joint may begin by the third week. As compared with the basic timing of the most common wrist rehabilitation protocols after SLIL ligament reconstruction, which require at least 6 weeks of immobilization, the total period of rehabilitation may be reduced from approximately 16 weeks to 12.
Fig. 7. The Dart-Splint is completed (A) Volar aspect; (B) dorsal aspect; (C) lateral aspect.
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
5
Fig. 8. Example of dart throwing motion with the Dart-Splint. (A) Extension/radial-deviation; (B) Flexion/ulnar-deviation
Discussion e critical aspects Fabrication of the orthosis requires practice and good knowledge of wrist anatomical landmarks. In order to improve precision and accuracy in the creation of this orthosis, we recommend a fluoroscopic evaluation to confirm the correct position of the rivets (Fig. 9) and the restricted motion at the PCR (Fig. 10). A critical aspect of the dart-splint may be that it does not allow a complete, unrestricted DTM. Since the DTM plane is variable and unique for each individual, the aim of the dart-splint is to provide a dynamic guide along the plane of DTM. In this way, the patient can begin to corticalize proprioceptively the correct kinematic sequential movements that occur during the DTM. At the same time, the use of this splint
can also stimulate neuromuscular control and improve dynamic stability that benefits rehabilitation of ligamentous disorders of the wrist.
Conclusions: future investigation on Dart-Splint and DTM The preliminary experience with the use of this orthosis demonstrates promising results in wrist rehabilitation. Further studies need to be performed in order to address the differences in anatomy and wrist movement, as demonstrated among patients with different lunate shape.13 As classified according to Viegas,14 the lunate type 1 permits a wide DTM with respect to lunate type 2. Following radiographic assessment of an individual with lunate
Fig. 9. Fluoroscopic control of correct placement of the rivets of the Dart-Splint. (A) Postero-Anterior view; (B) Lateral view.
6
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
Fig. 10. Dynamic fluoroscopy on lateral view of the patient’s wrist wearing the Dart-Splint is used to check the position of the lunate during DTM. ERD, extension/radial-deviation; FUD, flexion/ulnar-deviation.
type 1 or type 2, the therapist may personalize the dart-splint by modifying the positions of the hinges accordingly.
References 1. Moritomo H, Apergis E, Herzberg G, et al. 2007 IFSSH Committee Report of Wrist Biomechanics Committee: biomechanics of the so-called dart-throwing motion of the wrist. J Hand Surg Am. 2007;32:1447e1453. 2. Moritomo H, Murase T, Goto A, Sugamoto K, Yoshikawa H. In vivo 3-dimensional kinematics of the midcarpal joint of the wrist. J Bone Joint Surg Am. 2006;88: 611e621. 3. Vesalius A. De Humani Corporis Fabrica. Basle. 1543. 4. Henke W. Die Bewegungen der Handwurzel. Z Rat Med. 1859;7:27. 5. Linscheid RL. Carpal comprehension: a short look at a history of understanding the wrist joint. In: Cooney WP, Linscheid RL, Dobyns JH, eds. The Wrist. Diagnosis and Operative Treatment. St Louis: Mosby; 1998:2e13. 6. Moritomo H, Viegas SF, Nakamura K, et al. The scaphotrapezio-trapezioidal joint Part 1: an anatomic and radiographic study. J Hand Surg Am. 2000;25:899e910.
7. Moritomo H, Murase T, Goto A, et al. In vivo three-dimensional kinematics of the midcarpal joint of the wrist. J Bone Joint Surg Am. 2006;88: 611e621. 8. Calfee RP, Leventhal EL, Wilkerson J, et al. Simulated radioscapholunate fusion alters carpal kinematics while preserving dart-throwers motion. J Hand Surg. 2008;33A:503e510. 9. Upall MA, Crisco JJ, Moore DC, et al. In vivo elongation of the palmar and dorsal scapholunate interosseous ligament. J Hand Surg. 2006;31:1326e 1332. 10. Werner FW, Short WH, Green JK. Changes in patterns of scaphoid and lunate motion during functional arcs of wrist motion induced by ligament division. J Hand Surg. 2005;30A:1156e1160. 11. Werner FW, Green JK, Short WH, et al. Scaphoid and lunate motion during a wrist dart throw motion. J Hand Surg. 2004;29A:418e422. 12. Crisco JJ, Coburn JC, Moore DC, et al. In vivo kinematics and the dart thrower’s motion. J Bone Joint Surg Am. 2005;87A(12):2729e2740. 13. Mclean JM, Turner PC, Bain GI, et al. An association between lunate morphology and scaphoidetrapeziumetrapezoid arthritis. J Hand Surg Eur Vol. December 2009;34:778e782. 14. Viegas SF. The lunatohamate articulation of the midcarpal joint. Arthroscopy. 1990;6:5e10.
Contents lists available at ScienceDirect
Journal of Hand Therapy journal homepage: www.jhandtherapy.org
Practice Forum
Dart-Splint: An innovative orthosis that can be integrated into a scapho-lunate and palmar midcarpal instability re-education protocol Federica Braidotti PT a, b, *, Andrea Atzei MD a, Tracy Fairplay PT c, d a
Fenice Hand Surgery and Rehabilitation Team, Treviso Italy Fisiomano e Private Professional Upper Extremity Rehabilitation Center, Pordenone, Italy c Studio Fairplay e Private Professional Functional Rehabilitation of the Upper Extremity Clinic, Bologna, Italy d Hand Rehabilitation Unit, Policlinic, Modena, Italy b
The Authors describe a novel hinged orthosis that permits selective midcarpal mobilization along the plane of the dart throwing motion. This orthotic device can be used to assist rehabilitation protocols aimed to limit radiocarpal joint mobility and scapho-lunate ligament overload and to accelerate wrist functional recovery after ligamentous injuries around the proximal carpal row. e VICTORIA W. PRIGANC, PhD, OTR, CHT, CLT, Practice Forum Editor
Introduction Most activities of daily living (ADL) are performed using an oblique wrist motion. This movement proceeds from radial deviation-extension to ulnar deviation-flexion and has been called the dart thrower’s motion or the dart throwing motion (DTM).1 The DTM’s arc of movement is referred to as “the most stable and controllable plane of motion in a kinematic sense and represents the functional plane of wrist motion for occupational and vocational activities in which minimal wrist muscle force is used”.2 The concept of wrist movement along an oblique plane represents the actual evolution of carpal kinematics rather than the traditional concept that considered basic wrist movement running along the sagittal and coronal planes. A few centuries have passed since the time that carpal kinematics has been anatomically described by Vesalius in 1543,3 to the first complete study of carpal motion in cadaver wrists by Henke in 1859.4,5 He noted that the radiocarpal and midcarpal joints moved independently, with mutually perpendicular axes passing through the capitate. He therefore concluded that there was no “pure” motion in the joint and he was the first author to suggest
* Corresponding author. Viale Pasteur 6, Treviso 31100, Italy. Tel.: þ39 3478585715 (mobile); fax: þ39 0422698150. E-mail addresses: [email protected], federica.braidotti@fisiomano.com (F. Braidotti).
that wrist joint motion occurred around an oblique axis. Since this discovery, many publications and debates have been documented and have led to the publication of a report by IFSSH Committee Report of Wrist Biomechanics in 2007,1 which emphasizes the DTM from an anatomical, anthropological and biomechanical point of view. Kinematic review of dart throwing motion and rationale for the use of the Dart-Splint Before one begins to fabricate a Dart-Splint, it is of utmost importance to have a complete knowledge of wrist and more specifically midcarpal kinematics. The DTM takes place in the midcarpal joint and uses this joint to its maximum extent. This joint is an articular complex, in which the scaphotrapeziotrapezoid joint (STTJ)6 is the key joint that stabilizes and controls the DTM. The axis of the DTM plane runs obliquely from the radio-palmar aspect of the scaphoid tuberosity to the ulnodorsal aspect of the hamate7 (Fig. 1). The most interesting aspect is that the STTJ is a monoaxial joint, moving along a single axis that parallels with the plane of the DTM, whereas, the directions of motion of the Luno-Capitate and Triquetral-Hamate joints somewhat differ among wrist flexion-extension, radioulnar motion and DTM. The forearm muscles that are directly involved in generating the DTM are the Extensor Carpi Radialis Brevis and Longus (ECRL-B) and the Flexor Carpi Ulnaris (FCU). Looking at a transverse view of the wrist, one can note that the
0894-1130/$ e see front matter Ó 2015 Hanley & Belfus, an imprint of Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.jht.2015.01.007
2
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
the majority of daily functional activities. With these purposes, the authors developed a special orthotic device in order to facilitate protected midcarpal motion and named it the “DartSplint”. The Dart-Splint allows oblique wrist motion along the DTM plane, thus inhibiting movement of the healing structures following surgery or injury around the PCR.
Materials used 1. 2. 3. 4. 5. 6.
2.4 mm thermoplastic (Orfit) Adhesive hook velcro Non-adhesive loop velcro Rivets Plast-O-Fit Soft padding
Fabrication procedure
Fig. 1. Schematic drawing showing the orientation of the axis of the DTM, which runs obliquely from the radio-palmar aspect of the scaphoid tuberosity to the ulno-dorsal aspect of the hamate.
oblique orientation of DTM plane goes along the same axis that links the ECRL-B and FCU (Fig. 2). As suggested by Garcia-Elias, and confirmed by several biomechanical studies, DTM is produced as an almost “isolated” midcarpal joint motion, with a minimal involvement of the radio-carpal joint (RCJ).8 The radiograms of the lateral view of the wrist taken at both ends of the DTM (extension/radial-deviation and flexion/ulnardeviation) show that the position of the lunate remains “almost” unchanged (Fig. 3), thus confirming minimal movement of the RCJ.9 In addition, as demonstrated by Upal and coworkers9 and further biomechanical studies,10e12 the tensile stresses of the dorsal insertions of the scafo-lunate interosseous ligament (SLIL) are minimized during DTM. According to these kinematic findings, selective midcarpal mobilization along the DTM may be used for specific rehabilitation protocols aimed to limit RCJ mobility and SLIL overload. Therefore, healing of injured or repaired tissues around the proximal carpal row (PCR) may not be disturbed during early DTM. An additional advantage is also gained by early recovery of the specific motion needed for
Fig. 2. In the transverse section of the wrist, the arrow shows that the axis of DTM goes along the same line joining its muscolar motors: Extensor Carpi Radialis Brevis and Longus (ECRL-B) and Flexor Carpi Ulnaris (FCU).
1. The first step is to underline the anatomical landmarks in order to guarantee a precise construction of the Dart-Splint. The palmar hinge should lie above the scaphoid tubercle (easily palpable) and the dorsal hinge should lie at the same level, along the line of the ring finger’s metacarpal (which approximates the ulno-dorsal aspect of the hamate) (Fig. 4). The landmarks for the dynamic junction are very important and should be aligned with the DTM axis in order to allow movement along the DTM plane; 2. The orthosis is made of two static thermoplastic components: a carpal unit and an anti-brachial unit (Fig. 5). Once the malleable thermoplastic has been removed from the heated water 60 F, mold the material over patient’s hand at the carpal level. Attention should be paid that the hole for the thumb is not too large, excluding the palmar landmark over the scaphoid tubercle where the palmar hinge must lie. The anti-brachial unit is positioned 2 cm inferior to the carpal unit’s proximal border, molding it around the palmar aspect of the forearm. Both thermoplastic units should be closed on the hand’s and forearm’s ulnar side. 3. Underline the landmarks over both carpal and anti-brachial units; 4. Roll and flatten the Plast-O-Fit onto itself and mold it in order to obtain two little perfectly straight connecting bars (about 2 cm width 6 cm length) (Fig. 6); 5. The 2 connecting bars are interposed between the 2 units in order to form 2 dynamic junctions: one palmar-radial side, the other on the dorso-ulnar side of the orthosis. On the carpal unit, the distal portion of one of the Plast-O-Fit bars should be attached with a rivet to the dorsal landmark, and the distal portion of the other bar to the palmar landmark; 6. Once both dorsal and palmar bars are riveted to the carpal unit, it is then necessary that the patient puts on both units. On each bar, measure a distance of 2e3 cm from the base of the carpal unit to the distal rim of the anti-brachial unit, then allow an additional length of minimum of 2 cm on the proximal extremity of the bar for fixation on the antibrachial unit. 7. Take the splint off the patient and carefully heat the last 2 cm of both bars and mold them simultaneously onto the anti-brachial unit making sure that the bars are perfectly aligned with the rivet, 0 of inclination. Pay attention and be careful to attach the bars straight and parallel to each other;
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
3
Fig. 3. The position of the lunate remains unchanged on the lateral view radiograms of the wrist taken at both ends of DTM. (A) Extension/radial-deviation (ERD); (B) flexion/ ulnar-deviation (FUD).
Fig. 4. Landmarks for hinge positioning are drawn on patient’s skin. (A) Palmar landmark lies over the scaphoid tubercle and (B) dorsal landmark on the line of ring finger’s metacarpal.
Fig. 5. Static thermoplastic components of the Dart-Splint: (A) carpal unit and (B) anti-brachial unit.
4
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
8. After a few minutes, when the bars are firmly attached, try to test the movement of the orthosis with your hands, before putting the orthosis back on the patient (Fig. 7). 9. When the movement of the orthosis is fluid and the rivets turn easily, the orthosis is put back on the patient that can try the dart throwing movement protected by the orthosis (Fig. 8). 10. To provide further comfort to the patient, the orthosis can be padded along its borders.
Dart-Splint e indications
Fig. 6. Two connecting bars are made of Plast-O-Fit.
The “Dart-Splint” may be utilized in post-operative rehabilitation protocols in which it is necessary to immobilize the RCJ, such as following surgical repair or reconstruction of radio-carpal ligaments, scapho-lunate ligaments, midcarpal instability and radioscafo-lunate fusion. In addition, the Dart-Splint can also be recommended for conservative treatment of several types of predynamic and dynamic SLIL instability and palmar midcarpal instability. In the above-mentioned conditions, use of the DartSplint may allow the therapist to anticipate the start of the rehabilitation program. For example, the period of immobilization after SLIL reconstruction using the Dart-Splint may be reduced by 2 weeks and controlled mobilization of the midcarpal joint may begin by the third week. As compared with the basic timing of the most common wrist rehabilitation protocols after SLIL ligament reconstruction, which require at least 6 weeks of immobilization, the total period of rehabilitation may be reduced from approximately 16 weeks to 12.
Fig. 7. The Dart-Splint is completed (A) Volar aspect; (B) dorsal aspect; (C) lateral aspect.
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
5
Fig. 8. Example of dart throwing motion with the Dart-Splint. (A) Extension/radial-deviation; (B) Flexion/ulnar-deviation
Discussion e critical aspects Fabrication of the orthosis requires practice and good knowledge of wrist anatomical landmarks. In order to improve precision and accuracy in the creation of this orthosis, we recommend a fluoroscopic evaluation to confirm the correct position of the rivets (Fig. 9) and the restricted motion at the PCR (Fig. 10). A critical aspect of the dart-splint may be that it does not allow a complete, unrestricted DTM. Since the DTM plane is variable and unique for each individual, the aim of the dart-splint is to provide a dynamic guide along the plane of DTM. In this way, the patient can begin to corticalize proprioceptively the correct kinematic sequential movements that occur during the DTM. At the same time, the use of this splint
can also stimulate neuromuscular control and improve dynamic stability that benefits rehabilitation of ligamentous disorders of the wrist.
Conclusions: future investigation on Dart-Splint and DTM The preliminary experience with the use of this orthosis demonstrates promising results in wrist rehabilitation. Further studies need to be performed in order to address the differences in anatomy and wrist movement, as demonstrated among patients with different lunate shape.13 As classified according to Viegas,14 the lunate type 1 permits a wide DTM with respect to lunate type 2. Following radiographic assessment of an individual with lunate
Fig. 9. Fluoroscopic control of correct placement of the rivets of the Dart-Splint. (A) Postero-Anterior view; (B) Lateral view.
6
F. Braidotti et al. / Journal of Hand Therapy xxx (2015) 1e6
Fig. 10. Dynamic fluoroscopy on lateral view of the patient’s wrist wearing the Dart-Splint is used to check the position of the lunate during DTM. ERD, extension/radial-deviation; FUD, flexion/ulnar-deviation.
type 1 or type 2, the therapist may personalize the dart-splint by modifying the positions of the hinges accordingly.
References 1. Moritomo H, Apergis E, Herzberg G, et al. 2007 IFSSH Committee Report of Wrist Biomechanics Committee: biomechanics of the so-called dart-throwing motion of the wrist. J Hand Surg Am. 2007;32:1447e1453. 2. Moritomo H, Murase T, Goto A, Sugamoto K, Yoshikawa H. In vivo 3-dimensional kinematics of the midcarpal joint of the wrist. J Bone Joint Surg Am. 2006;88: 611e621. 3. Vesalius A. De Humani Corporis Fabrica. Basle. 1543. 4. Henke W. Die Bewegungen der Handwurzel. Z Rat Med. 1859;7:27. 5. Linscheid RL. Carpal comprehension: a short look at a history of understanding the wrist joint. In: Cooney WP, Linscheid RL, Dobyns JH, eds. The Wrist. Diagnosis and Operative Treatment. St Louis: Mosby; 1998:2e13. 6. Moritomo H, Viegas SF, Nakamura K, et al. The scaphotrapezio-trapezioidal joint Part 1: an anatomic and radiographic study. J Hand Surg Am. 2000;25:899e910.
7. Moritomo H, Murase T, Goto A, et al. In vivo three-dimensional kinematics of the midcarpal joint of the wrist. J Bone Joint Surg Am. 2006;88: 611e621. 8. Calfee RP, Leventhal EL, Wilkerson J, et al. Simulated radioscapholunate fusion alters carpal kinematics while preserving dart-throwers motion. J Hand Surg. 2008;33A:503e510. 9. Upall MA, Crisco JJ, Moore DC, et al. In vivo elongation of the palmar and dorsal scapholunate interosseous ligament. J Hand Surg. 2006;31:1326e 1332. 10. Werner FW, Short WH, Green JK. Changes in patterns of scaphoid and lunate motion during functional arcs of wrist motion induced by ligament division. J Hand Surg. 2005;30A:1156e1160. 11. Werner FW, Green JK, Short WH, et al. Scaphoid and lunate motion during a wrist dart throw motion. J Hand Surg. 2004;29A:418e422. 12. Crisco JJ, Coburn JC, Moore DC, et al. In vivo kinematics and the dart thrower’s motion. J Bone Joint Surg Am. 2005;87A(12):2729e2740. 13. Mclean JM, Turner PC, Bain GI, et al. An association between lunate morphology and scaphoidetrapeziumetrapezoid arthritis. J Hand Surg Eur Vol. December 2009;34:778e782. 14. Viegas SF. The lunatohamate articulation of the midcarpal joint. Arthroscopy. 1990;6:5e10.