Abstract
Traumatic injuries of the metacarpophalangeal joints are a common occurrence in professional and recreational sports such as boxing and martial arts, especially the fourth and fifth metacarpals. Injury usually results from a forceful impact with a clenched fist. The spectrum of injuries varies from simple skin laceration to extensor mechanism disruption, dorsal capsule rupture, metacarpal fractures and carpometacarpal joint injuries. These injuries are well documented in boxers as well as in patients who had been involved in fights and assaults. We report on two patients sustaining similar injuries to the dorsum of the hand but following punching of a recreational ’punching machine’. We describe the patterns of injury encountered and summarise the treatment. For clinical and safety reasons as well as the potential medicolegal implications, we believe it is important to highlight this mechanism of injury.
Keywords: Boxing, Boxer’s knuckle, Recreational injury
Traumatic injuries of the metacarpophalangeal (MCP) joints are a common occurrence in professional and recreational sports such as boxing and martial arts, especially the fourth and fifth metacarpals. Injury usually results from a forceful impact with a clenched fist.1 The spectrum of injuries varies from simple skin laceration to extensor mechanism disruption, dorsal capsule rupture, metacarpal fractures (MC) and carpometacarpal (CMC) joint injuries. These injuries are well documented in boxers as well as in patients who had been involved in fights and assaults. We report on two patients sustaining similar injuries to the dorsum of the hand but following punching of a recreational ‘punching machine’ located in a bar.
We describe the patterns of injury encountered and summarise the treatment. We also establish the hazard of these machines and provide evidence that some sort of warning may be warranted. For clinical and safety reasons as well as the potential medicolegal implications, we believe it is important to highlight this mechanism of injury.
Case history 1
A 27-year-old male, right hand dominant patient presented to our trauma team with laceration, pain and swelling of the dorsum of the right middle MCP joint after a night out. An interview revealed that the patient had been competing for the most powerful punch at a local pub on a punching machine. On examination, the patient had a 2cm laceration over the dorsal MCP joint of the third digit. The range of movement of the extensor was reduced with no neurovascular damage. The decision was made to explore the laceration in theatre. On exploration, the patient was found to have a ruptured third MCP joint capsule with an intact extensor mechanism. The capsule was primarily repaired and the patient was discharged the same day with outpatient follow-up.
Case history 2
A 26-year-old male, right hand dominant patient presented with a similar history where he had been using a punching bag in a pub. He had sustained lacerations on the dorsum of the right index and middle finger MCP joints following punching the bag, which deflated on impact, resulting in the punch landing on the central metal bar of the bag. The range of movement of the extensor was reduced on examination and there was a neurovascular deficit. The wound was explored in theatre and no injuries to deep structures were found. The lacerations were closed primarily and the patient was discharged home.
Discussion
Boxing is a popular sport throughout the world and injuries to the dorsum of the hand are fairly common in this sport. Whether recreational or professional, the spectrum of injury varies. The characteristic injury is the ‘boxer’s knuckle’, which involves disruption of the extensor hood mechanism with dorsal capsule rupture.2 This injury can be severely disabling with devastating effects for the athlete. The spectrum of injuries further extends to simple contusions, lacerations, extensor tendon ruptures or subluxation and MC/ CMC fractures.1,3
Usually, the mechanism of injury is severe blunt trauma with forceful flexion of joints resulting in stretching of the extensor mechanism.3 The injury could be closed or open. The mechanism of open injuries can involve avulsion, crushing or impact with a sharp object. A thorough history and clinical examination is crucial to identifying the extent of the injury as sinister injuries can be easily overlooked, especially capsular tears, which could result in synovitis, and fistulas between joint cavity and subcutaneous tissue.1,4 The usual symptoms include joint pain, swelling, tenderness and reduced joint extension. Sometimes a palpable defect can be detected on clinical examination at the site of rupture.1,3 A plain radiograph is performed to exclude any bony injury and, if a capsular tear is suspected, an arthrogram was recommended in one study to assess capsular integrity.5
Treatment of extensor mechanism injuries depends on the severity of the injury and structures involved. Simple lacerations to the skin and extensor tendons can be repaired primarily. However, management of deeper structures such as sagittal bands, tendon dislocation and capsular tears remains controversial. Some authors advocate surgical treatment while others prefer a non-operative course. Usually, extensor mechanism disruption is treated with surgery.3 For capsular tears, Arai et al suggested surgical repair5 but in another study complete functional recovery was seen in athletes without repair.3 Meticulous postoperative care is needed for complex injuries with appropriate splinting and follow-up. Whatever the course, the prime goal is to return the hand to its previous functional state.
Conclusions
To our knowledge the two cases reported here are the first in the literature with injury to the MCP joint capsule caused by punching bags provided for entertainment. Punching bags are being introduced widely in pubs and can pose a significant risk of injury to the dorsum of the hand. Accident and emergency physicians as well as surgeons dealing with trauma need to be aware of potential injuries that can be caused by such machines as they can be easily missed and can cause significant functional impairment.
References
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