Figs. 24.1 and 24.2
Giorgia Gregorio wakeboarding (Photo courtesy of Ricardo Pinto)
In Germany with its 82 million people, around 20,000 active wakeboarders are currently estimated, with 50 towing devices installed throughout the country. In the USA in 2014, the number of wakeboarding participants was estimated at 3,125,000 . This chapter highlights both injuries (acute and overuse) and illnesses related to wakeboarding.
Wakeboarding boats are equipped with a wakeboard tower, a thick-walled stainless steel or aluminium tubing structure, which places the pull point about 2 m above the water’s surface. The athlete holds a triangular bar, measuring about 32 cm in length, with one or both hands—the rope is generally 20–25 m in length—and uses stiffer ropes than water skiing, because no-stretch tighter rope helps riders to get more air and to perform flips and spins. In cable wakeboarding, the athlete is pulled by a rapid cableway, using a towline measuring about 20 m in length, suspended at an angle of 10–70°, at a round running about 30 km/h. Boards are usually in fibreglass, with a core of foam, honeycomb or wood and resin. The shape and positioning of the fins may vary according to the rider’s preference and types of tricks performed: finless boards are also used for particular tricks, especially in cable parks. Many boards are bidirectional, meaning they can be ridden in both directions: both the left and right foot can be adopted as the forefoot, allowing maximum freedom of action during the freestyle manoeuvres. Wakeboarding bindings are generally of the boot type, with adjustable straps, laces or buckles.
24.2 Acute Injuries
Serious acute injuries and even death can occur from wakeboarding participation : fatalities have been reported as a consequence of subdural haematoma following head trauma and from blunt cardiac trauma resulting in free wall rupture [2, 3]. Of the 122 injuries reported by 56 orthopaedic surgeons in a US-based analysis by Carson in 2004 , 21 % were represented by fractures, which mainly involved the thoracic or lumbar spine, femur, tibia, calcaneous and ribs. These injuries demonstrate that significant forces are being generated as the wakeboarder falls or simply lands hard on the water : in addition to the speed of the boat or cable system, trajectory jumps and manoeuvres can generate significant deceleration and rotational forces. Almost all of the injuries occurred as a consequence of a direct or twisting impact with the water surface and not as a result of collision with obstacles such as docks, floating structures or watercrafts .
Baker et al., based on the data of the National Electronic Injury Surveillance System (NEISS) between 2000 and 2007, reported an estimated 18,967 wakeboarding-related injuries in the USA and an overall injury rate of 0.81 per 100,000 participants . The authors also found that the injury rate more than doubled over this period. The age distribution of injuries showed a peak in late adolescence to early adulthood, then decreased with age, probably due to the popularity of this sport among youngsters. While a 33 % decrease in the number of the younger participants was found over the period of the study, the rate of injuries remained relatively stable: this led the authors to conclude that those who continue to practise wakeboarding were the participants who were the most reckless and who engaged in more extreme manoeuvres [4, 5]. The head and neck region was affected in 47.9 % of the cases: most of the injuries being represented by lacerations (51.3 %) and concussions (24.9 %) . The hip and lower extremities were injured in 26.5 % of cases, and most of the injuries were strains and sprains (57.3 %) or fractures (21.3 %) . Injuries to the shoulder/upper extremity and trunk accounted for 14.8 % and 10.6 % of injuries, respectively, and dislocations represented the most common diagnosis among upper extremity injuries (33.7 %) .
In a prospective study on cable wakeboarding involving 122 wakeboarders, Patzer et al.  found an overall injury rate of 32 injuries per 1000 h of practice: 12 per 1000 h of practice when considering only injuries requiring medical attention. Out of 277 reported injuries, 108 (39 %) were treated medically. The knee, shoulder and head were the most frequently injured regions, and minor injuries prevailed: 61 % of the injuries were mild, 15 % very severe, 14 % severe and 10 % medium-severe. Wakeboarding behind the boat is related to more serious injuries than cable wakeboarding, probably because of unpredictable disturbances such as the bow wave of the boat or natural obstacles [2, 5, 6]. Conversely in cable wakeboarding, the most common injury mechanism involves landing from a rotation jump over an artificial obstacle. Injury rate per participant correlates with increasing skills, injuries being mainly related to manoeuvres such as rotational jumps practised by more skilled athletes. Injury rate also increases with higher body weight and height, while material-related factors such as board length, bond type and manufacturer were not found to have any significant influence on injuries .
24.2.1 Head Injuries
The descriptive study by Hostetler et al.  involving 95 injured wakeboarding participants reported the head as being the most commonly affected body area, being involved in 29 % of injuries. Conversely, head injuries represented the smallest percentage of reported trauma for water skiers (4.3 %). Wakeboarders also sustained significantly more traumatic brain injuries (12.5 % of all injuries) than did water skiers (2.4 %). Lacerations were the most common diagnosis for wakeboarders (31.1 % of all injuries), and the majority (59.6 %) were to the face. Head injuries were mainly represented by midface contusions and lacerations also in cable wakeboarding and prevailed among beginners [2, 6]. A number of cases of eardrum rupture were reported in studies on wakeboarding injuries [2, 6], caused by the edge of the wakeboard catching the water and suddenly stopping, causing the athlete to fall, impacting the water headfirst. If one side of the head slaps into the water, the column of air contained within the external auditory ear canal is forced against the tympanic membrane and can cause it to rupture.
As early as in 2000, a Chinese case report discussed a 14-year-old male who sustained an unusual intracranial subdural haemorrhage while wakeboarding: the injury was attributed to the combination of both acceleration-deceleration and rotational forces . Carson  also reported the case of a 21-year-old male wakeboarder, who sustained a subdural haematoma after hitting his head on the water while attempting a flip . An acute ischemic stroke of the right basal ganglia and adjacent internal capsule, due to right internal carotid artery dissection, followed by one particular wakeboarding accident, is more recently reported by Fridley et al. . The injury mechanism in that case probably involved high rotational deceleration of the body on the water and whiplash-type movements of the head and neck on impact.
24.2.2 Shoulder Injuries
Shoulder dislocations were the second most common injuries (14.7 %), following anterior cruciate ligament (ACL) tears, among 122 orthopaedic reported injuries examined by Carson . In the series on cable wakeboarding by Patzer et al. , shoulder injuries were less frequent among expert athletes and were as follows: one shoulder dislocation as a consequence of a fall in the water, six long biceps tendon lesions, one tear of the biceps tendon anchor (SLAP lesion), three strains of the rotator cuff and one avulsion fracture of the greater tuberosity. Lim et al.  reported the case of a 32-year-old Chinese man suffering from rupture of both the sternal and clavicular attachments of the pectoralis major with muscle retraction of about 5 cm, as a consequence of a wakeboarding accident: he fell sharply on the water surface with his right shoulder in forced abduction and external rotation. This is a rare condition, with only about 200 cases reported in literature: it is frequently under- or misdiagnosed; therefore, it is important to be aware that it may occur as a consequence of wakeboarding falls. Two cases of closed proximal muscle rupture of the biceps brachii after wakeboarding traumas have also been described .
24.2.3 Wrist and Hand Injuries
In a case report, we highlighted a case of acute median nerve injury, following rope strangulation in a mechanical towing machine . An intermediate male athlete with 12 months’ wakeboarding experience was training on Germany’s largest circular cable system, installed on a lake, at a speed of 40 km/h, when the system stopped suddenly due to an overlapping wire. The boarder dived in the lake, and his trunk and hand became trapped in the system’s mechanism. He managed to free his body, but his wrist was still trapped when the system began operating once more without warning. He was pulled a quarter of the way around the lake at the previous speed of 40 km/h, suffering a strangulation of his wrist with immediate numbness of the area of the left hand supplied by the median nerve: he also sustained a laceration on the palmar aspect of the wrist measuring 0.5 × 5 cm. In the operating room, the dorsal compartment pressure of the forearm and the palmar compartment of the flexor carpi ulnaris muscle were both normal, measuring 16 and 19 mmHg, respectively. Seventy-two hours after the initial strangulation injury, the median nerve showed hyperaemia and moderate swelling and limited haematoma in the carpal tunnel more consistent with a median nerve contusion. The palmar branch of the median nerve was surrounded by a significant haematoma, which was evacuated. The ulnar nerve was inspected and found to be without any significant signs of injury or haematoma. On the first postoperative day, the patient regained the sensory function of the hand following 72 h of acute carpal tunnel syndrome with median nerve contusion, with remaining dysaesthesia of the thenar skin supplied by the palmar branch of the median nerve. On the fifth postoperative day, the patient was discharged home after an uneventful postoperative course.
Cable-associated injuries such as the aforementioned nerve contusions following wrist strangulation may not be uncommon in wakeboarding. In the UK , a 55-year-old man sustained a traumatic amputation of his dominant right hand while acting as an amateur wakeboarding instructor. The patient was in the water, assisting the launch of a novice wakeboarder, when the tow cable became wrapped around his wrist. The driver of the towing Jet Ski called out to ask if everyone was ready to start, as is standard practice in towing water sports, misheard the patient’s reply of ‘no’ as ‘go’ and started to drive. The tow cable tightened around the patient’s wrist, amputating the distal forearm at wrist level. The hand was lost to the sea, making re-plantation impossible, with a significant impact on the patient’s daily life as a manual worker. The contaminated injury was treated according to military principles, with primary debridement and delay closure .