Imaging of Wrist Injuries 201 Imaging of Wrist Injuries 13 Wilfred C. G. Peh and Howard R. Galloway CONTENTS 13.1 Introduction 13.1 Introduction 201 13.2 Sports Injuries in Children 202 The benefi ts of sports are well- recognized but many sports-related activities carry a specifi c injury risk. 13.3 Anatomy 203 Injuries to the wrist and hand occur with a frequency 13.4 Biomechanics of Sports Injuries 204 of between 3% and 9% (Geissler 2001). This injury 13.4.1 Overview 204 incidence will obviously be higher in those sports uti- 13.4.2 Fractures 205 lizing the hand and wrist, and where the potential for 13.4.2.1 Radial Fractures 206 13.4.2.2 Scaphoid Fractures 206 trauma during sporting activity is present. Trauma to 13.4.2.3 Hamate Fractures 206 the wrist may cause bone or soft tissue injury, which 13.4.2.4 Lunate Fractures 207 may sometimes be diffi cult to diagnose. Symptoms 13.4.3 Wrist Instability 207 vary, according to the structure involved or nature 13.4.4 Post-traumatic Deformity Patterns 208 13.4.5 TFCC Injuries 208 of injury, but pain and limited joint function are the 13.4.6 Tendon Injuries 209 usual complaints. Physical examination may be dif- 13.4.7 Neurovascular Injuries 209 fi cult due to the proximity of many small bony and 13.5 Specifi c Types of Sports Injuries 210 soft tissue structures, as well as small articulations. 13.5.1 Golf, Baseball and Racquet Sports 210 The wide spectrum of sporting activities places 13.5.2 Gymnastics 211 demands of different magnitudes, orientations, and 13.5.3 Rowing/Canoeing, Volleyball and degrees of repetitions on the wrist. These injuries Basketball 216 may result from a single debilitating or repetitive 13.5.4 Cycling/Wheelchair Athletes 217 13.5.5 American Football, Horse Riding/Rodeo, traumatic episodes. Proper diagnosis of injuries in Roller-Skating/Rollerblading/ this region therefore requires a basic knowledge of Skateboarding 217 the anatomy and biomechanics of the wrist (Halikis 13.5.5.1 American Football 218 and Taleisnik 1996). Many sporting activities are 13.5.5.2 Horse Riding/Rodeo 218 13.5.5.3 Roller-Skating/Rollerblading/ associated with a specifi c injury pattern related to Skateboarding 218 the actions and stresses associated with that particu- 13.5.6 Snowboarding and Skiing 219 lar activity. Knowledge of the sport or recreational 13.6 Conclusion 220 activity therefore aids in the diagnosis of these inju- ries. Early diagnosis of the injury and proper refer- Things to Remember 220 ral of these patients can help prevent complications, References 221 including prolonged pain and discomfort, surgery, and lost time from sports participation. Failure to diagnose sports injuries may lead to permanent dis- ability (McCue et al. 1979). W. C. G. Peh, MD, MBBS, FRCPE, FRCPG, FRCR It is important for athletes to be educated about how Clinical Professor and Senior Consultant Radiologist, to recognize wrist injuries promptly. Seeking early Singapore Health Services, 7 Hospital Drive, #02-09, Singapore medical attention for wrist injuries should be empha- 169611, Republic of Singapore sized to athletes. Specifi c care to wrist-supporting lig- H. R. Galloway, BMBS, FRANZCR Clinical Associate Professor, Department of Radiology, aments and muscles is necessary to prevent overuse Australian National University, The Canberra Hospital, Yamba injuries during the recovery period and return of func- Drive, Garran, ACT 2605, Australia tion. For pre-adolescent and adolescent athletes, injury 202 W. C. G. Peh and H. R. Galloway Box 13.1. Radiography Box 13.4. Arthrography ● ● Standard frontal and lateral radiographs are Useful for diagnosis of ligament and TFCC the initial imaging investigation for detection tears of fractures and malalignment ● Single versus triple compartment injection technique ● Classifi cation of distal radial fractures are made on radiographs ● Single radiocarpal injection followed by either CT or MR imaging is now commonly practised ● Special projections may be needed for scaph- oid, hamate hook and other carpal fractures ● Stress radiographs or videofl uoroscopy may be Box 13.5. Ultrasonography required to show dynamic carpal instability ● Provides answers to very specifi c diagnostic questions for superfi cial lesions such as tendon abnormalities ● Cheaper and time-saving compared to MR Box 13.2. Computed Tomography imaging ● Useful in supplementing normal or equivocal ● Highly operator-dependent with long learning radiographs in clinically-suspected injury curve ● Availability of high-frequency transducer is ● Accurate for diagnosis of hook of hamate frac- essential tures and DRUJ subluxation/ dislocation ● Helpful in assessment of healing and post-trau- matic deformity Box 13.6. Magnetic Resonance Imaging ● Provides a comprehensive overview of injuries to both bone and soft tissue structures such as muscle, tendon, tendon sheath, nerve and Box 13.3. Bone Scintigraphy vessels ● ● Useful only while bone is still remodelling May be performed following arthrography ● MR arthrography is useful for TFCC and SL ● Helpful in radiographically-occult trauma and LT tears to a growing wrist requires a more gradual return to full sporting activity than a non-growing wrist. Wrist 13.2 injuries may potentially be prevented by implement- Sports Injuries in Children ing proper technique, maintaining good strength and fl exibility and if the particular sports permit, using Hand and wrist injuries are more common in pre- wrist guards. The use of wrist guards may help protect adolescent and adolescent athletes than in adults from fractures and skin scrapes if one falls or slides in (Geissler 2001). It is particularly important to rec- sports such as rollerblading, or hockey. Proper stretch- ognize wrist injuries that occur in the immature skel- ing is especially useful for sports that involve a lot of eton, such as gymnast’s wrist (Fig. 13.1), as continued upper extremity bodywork, such as racquet sports. sports participation in affected children may result in Imaging of Wrist Injuries 203 growth arrest and other long-term problems. Injured occurring during wheel sports are in cycling (63%). children should therefore abstain from the sport until The radius/ulna is the most frequent fracture loca- the symptoms disappear and the wrist has healed tion (36%) (Lyons et al. 1999). Hassan and Dorani completely (Morgan and Slowman 2001). World- (2001) found that soccer, rollerblading, cycling and wide, an increasing number of children are involved netball injuries are the most frequent causes of the in competitive and organized sports. The frequency fractures. Soccer and rollerblading are the common- and severity of both acute and overuse injuries are est cause of fractures among boys, while rollerblading continuing to rise (Flynn et al. 2002). and netball injuries are most frequent cause among Sprains (34%), contusions (30%) and fractures girls. Brudvik and Hove (2003) found that scaphoid (25%) are the most common injury types (Damore fracture, an infrequent fracture in children, is seen in et al. 2003). The six most common sports causing 9% of all fractures due to rollerblading/skating, with injuries in children are basketball (19.5%), football a doubled risk of fracture in boys aged 13–15 years (17.1%), baseball/softball (14.9%), soccer (14.2%), compared with girls. rollerblading/skating (5.7%), and hockey (4.6%). Sprains/strains (32.0%), fractures (29.4%), contu- sions/abrasions (19.3%), and lacerations (9.7%) account for 90% of injury types. The most common injury location is the wrist/hand (28%). Contact with 13.3 another person or object is the mechanism for more Anatomy than 50% of the sports-related injuries (Taylor and Attia 2000). The wrist is a complex joint that is comprised of Most ball-related injuries occur during soccer bones and soft tissue structures. The bones consist of and rugby (86%), while the majority of fractures the distal radius and ulna, eight carpal bones, and the proximal metacarpal bones. The eight carpal bones are arranged in two rows to form a compact unit. The proximal carpal row is formed by the scaphoid, lunate, triquetrum and pisiform, and articulates with the distal end of the radius and the triangular fi bro- cartilaginous complex (TFCC). The distal carpal row is formed by the trapezium, trapezoid, capitate and hamate, and articulates with the proximal surfaces of the metacarpal bones. The ulna does not articulate directly with the carpus. The wrist is composed of a series of articulations that are separated into several major joint compartments, including: the radiocar- pal, distal radioulnar, pisiform-triquetral, midcarpal, fi rst carpometacarpal, and intermetacarpal joints. The carpal bones are held together by a complex set of ligaments, including the intrinsic (or interosseous) and extrinsic ligaments. These strong ligamentous attachments help stabilize the wrist. The dorsal liga- ments are weaker than the volar ligaments, resulting in dorsal dislocation being more common. Intrinsic (or interosseous) ligaments connect pairs of carpal bones. In the proximal carpal row, the scapholunate and lunotriquetral ligaments join the proximal, dorsal and volar margins of these carpal bones, and separate the radiocarpal from the midcarpal compartments. The extrinsic ligaments are formed by thickenings of Fig. 13.1. Female adolescent gymnast. PA radio- graph shows stress changes of the distal radius, the inner surface of the joint capsule, and are located with sclerosis adjacent to the irregularly-margin- dorsally and volarly. The main dorsal extrinsic liga- ated growth plates ments are the radiotriquetral, triquetrotrapezial and 204 W. C. G. Peh and H. R. Galloway triquetroscaphoid ligaments. The main volar extrin- sic ligaments are the radioscapholunate, and the long 13.4 radiolunate and short radiolunate ligaments. Biomechanics of Sports Injuries The TFCC is an important stabilizer of the wrist. Its main component is the triangular fi brocartilage 13.4.1 (TFC) disc, which separates the radiocarpal com- Overview partment from the distal radioulnar joint (DRUJ).