Injury risk in professional boxing.

Objective: Although a popular endeavor, boxing has fallen under increased scrutiny because of its association with traumatic brain injury. However, few studies have investigated the overall epidemiology of boxing injuries from representative samples, and no study has ever documented the incidence of injuries in female boxers. This study is a review of professional boxing data from the state of Nevada from September 2001 through March 2003.

Materials and Methods: Medical and outcome data for all professional boxing matches occurring in Nevada between September 2001 and March 2003 (n = 524 matches) were analyzed on the basis of a pair-matched, case-control design. Cases were boxers who received an injury during the boxing matches. Boxers who were not injured served as control subjects. Both conditional and unconditional logistic regression models were used to assess risk factors for injury.

Results: The overall incidence rate of injury was 17.1 per 100 boxer-matches, or 3.4 per 100 boxer-rounds. Facial laceration accounted for 51% of all injuries, followed by hand injury (17%), eye injury (14%), and nose injury (5%). Male boxers were significantly more likely than female boxers to receive injuries (3.6 versus 1.2 per 100 boxer-rounds, P = 0.01). Male boxing matches also ended in knockouts and technical knockouts more often than did female matches (P < 0.001). The risk of injury for those who lost the matches was nearly twice the risk for the winners. Those who lost by knockout had double the risk of injury compared with those who lost by other means. Neither age nor weight was significantly associated with the risk of injury.

Conclusions: The injury rate in professional boxing matches is high, particularly among male boxers. Superficial facial lacerations are the most common injury reported. Male boxers have a higher rate of knockout and technical knockouts than female boxers. Further research is necessary to determine the outcomes of injury, particularly the long-term neurologic outcome differences between sexes.

Key Words: boxing, head injury, professional sports 

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Professional boxing in the state of Nevada is a popular endeavor. A recent heavyweight match in Nevada included more than 17,000 in paid attendance and grossed in excess of $16 million in sales. (1) Despite its popularity, professional boxing has come under increased scrutiny over the past 30 years because of its association with both acute and chronic traumatic brain injury. (2-18) Recent reports have attributed a variety of injuries to participants of boxing including facial lacerations, (19) eye injuries, (20) hand injuries, (21) cardiac and pericardial injuries, (22) and acute renal injuries. (2)

In discussing boxing injuries, most reports have focused on traumatic brain injury or on specific cases of acute injuries. Few studies have documented the epidemiology of injury in professional boxing based on representative samples, especially regarding injuries in female professional boxers. This study aims to examine the injury patterns, incidence, and risk factors in a large, consecutive sample of professional boxing matches.

Materials and Methods

Boxing data from all professional boxing matches in the state of Nevada from September 2001 until March 2003 (n = 524 matches) was obtained from the Nevada State Athletic Commission. All professional boxing matches occurring in the state during the study period were included. Amateur boxing matches were excluded from the study. Data obtained included the identification numbers, sex, date of birth, weight, rounds fought, whether the boxer won or lost, how the match ended (knockout, technical knockout, decision, draw, disqualification, or no decision), and the incidence of injuries in the match and the type of injuries received. These data are in the public domain and accessible on the web site of the Nevada State Athletic Commission.

Medical and outcome data for all professional boxing matches were analyzed on the basis of a pair-matched, case-control design. Cases were boxers who sustained an injury during the boxing matches. Boxers who were not injured served as control subjects. Both conditional and unconditional logistic regression models were used to assess risk factors for injury.

Injuries were recorded on the basis of the clinical report of the physician at ringside. No follow-up study was done to ensure the accuracy of the clinical diagnosis, based on radiography or other diagnostic testing. Injuries were broken into the 13 broad classifications: eye injuries, facial lacerations, ear injuries, nose injuries, mouth injuries, jaw injuries, hand injuries, shoulder injuries, elbow injuries, ankle injuries, foot injuries, chest injuries, and abdominal injuries. Lacerations to the eyelid and nose were counted as facial lacerations. Only those injuries documented as other than lacerations--such as possible orbit fractures or a nose deformity--were listed as eye or nose injuries, respectively.

The Johns Hopkins University School of Medicine's Institutional Review Board approved the study protocol via exemption.

Results

A total of 524 matches were included in the study, with 92.2% of the participants being male (Table 1). There were 688 individual boxers with 69.2% participating in a single match and 20.1% participating in two matches; one boxer participated in 10 matches, the most for a single boxer during the study. Both male and female boxing matches most often resulted in "decisions" with judges scoring the match and determining the winner. However, male boxing matches were significantly (P < 0.001) more likely to end in technical knockouts (TKO) and knockouts (KO) (Fig. 1 and Table 2).

The overall incidence rate of injury was 17.1 per 100 boxer-matches, or 3.4 per 100 boxer-rounds. Facial laceration was the most common injury and accounted for 50.7% of all injuries (Fig. 2 and Table 1). Boxers at the 25 to 36 year age group had the highest injury incidence rate (Table 3). Male boxers were significantly more likely than female boxers to receive injuries (3.6 versus 1.2 per 100 boxer-rounds, P = 0.01). Weight difference within respective weight classes was not significantly associated with the risk of injury (Table 3). The risk of injury for those who lost the matches was nearly twice the risk for the winners. The incidence of injury was significantly greater for those fighters who lost a match by knockout as compared with other means of losing (Table 4). Multivariate logistic regression modeling (both conditional and unconditional) revealed that outcome of the fight was the only variable significantly associated with the risk of injury. The odds of injury for those who lost was more than twice the odds for those who won (adjusted OR, 2.47; 95% CI, 1.65 to 3.69).

[FIGURE 1 OMITTED]

Discussion

Boxing matches are unique to sports, in that "the nature of this activity causes injury by intention rather than by accident." (2) Much has been said regarding the risk of traumatic brain injury in professional boxing matches, but only two articles have been published worldwide since 1980 citing the incidence of all injuries during professional boxing matches. (19) No previous article has compared injury rates and boxing match result information between male and female boxers, as professional boxing matches involving female fighters is a relatively new phenomenon.

The giving and receiving of forceful blows to the head, neck, and torso places the boxer at risk for a variety of injuries. Facial lacerations, eye injuries, "cauliflower" ears, hearing impairment, nose injuries, hand injuries, (21,23) cardiac and pericardial injuries, (22) and acute renal injuries have been reported in the literature. (2) In 2003, Zazryn et al (19) reported the incidence of overall injuries occurring in male professional boxers in Victoria, Australia. Facial lacerations were the most common injury reported, with an overall injury rate of 25 injuries per 100 fight participations, higher than that for all types of injury observed in this study.

It should be noted that in this study a knockout was not regarded as an injury by itself. However, neurologic dysfunction significant enough to cause the clinical "knocked out" picture is no doubt evidence of damage, and it can be argued that a knockout may represent severe injury. Previous studies have demonstrated the acute and chronic danger of repetitive head injury, (4,12,24-30) especially when received with such frequency and velocity as to render a man unconscious; there is, however, discussion as to whether the acute clinical presentation of head injury--instant unconsciousness and loss of postural tone--is due to the overall ferocity of the blow or a reflex mechanism initiated at impact. (6) Boxers who receive more frequent head blows, (6) a higher number of bouts, (4,12,31) and a higher number of knockouts and technical knockouts (10) appear to have a increased incidence of positive CT findings and a higher risk of long-term neurologic disability--such as dementia pugilistica--especially in susceptible populations.

Female and male boxing matches have differing rates of injury and differing incidence of knockouts and technical knockouts. In Nevada, almost 10% of the professional boxing matches are between females. Female boxers fight fewer rounds per match and have significantly lower injury risk per boxer-round than their male counterparts. Most of these injuries are centered around the face, with superficial lacerations being the most common injury. More important than these superficial injuries is a male knockout rate that is greater than 5 times higher than the female rate. This probably is due to the increased punching power of heavier male boxers, but further studies are necessary to determine the cause. Boxers who lose a match because of a knockout have double the risk of injury when compared with those who lose by points or other means.

Despite padded protection for the hands of participants, hand injuries were noted as the second most common injury. Punches thrown by professional heavyweight boxers can generate significant force--equivalent to a 6-kg wooden mallet striking at 20 mph, according to one study (32)--and therefore put the hands at risk. Previous studies have demonstrated that boxing is a particular risk for hand injury, including fractures of the metacarpal and carpal bones (21) and soft tissue damage. (23) Eye injuries were also reported with high frequency in Nevada, although it should be noted that these injuries are described as general injuries to the eye region (ie, orbital edema) and not necessarily injuries to the globe. Though the entire facial region--including the eye--is at high risk for injury during boxing matches, the incidence of eye injury could possibly be lower than once reported in the literature. (20)

In an effort to make the sport of professional boxing safer for its participants, some have advocated the use of protective headgear and more heavily padded gloves, much like participants in the amateur ranks. However, it seems that unless blows to the head are limited, the sport will continue to expose its participants to undue levels of risk regardless of the protective measures in place. (17)

Limitations

In this study, the key limitation is the lack of diagnostic testing of boxing participants to confirm clinical diagnosis. All reported injuries were documented after a ringside examination by a physician. It is probable that the incidence of injury was underreported because of a lack of thorough laboratory and radiographic testing. Another limitation is the lack of amateur boxers. All participants in this study were professional and lacked the additional protective gear of amateur boxers. How this additional gear might have changed the incidence of injury is unknown.

Conclusion

The injury rate in professional boxing matches is high, with male boxers at a higher risk of injury than female boxers. Superficial facial lacerations are the most common injury reported. Male boxers have a higher rate of knockout and technical knockouts and thus are theoretically at a higher risk of long-term disability from neurologic injury.

Acknowledgments

The authors thank Peter L. Freije for his help in the design of the study protocol.

References

1. Nevada State Athletic Commission, Available at: http://boxing.nv.gov/gates.htm. Accessed September 2004.

2. Unterharnscheidt, F. A neurologist's reflections on boxing, I: Impact mechanics in boxing and injuries other than central nervous system damage. Rev Neurol 1995;23:661-674.

3. Unterharnscheidt, F. A neurologist's reflections on boxing, V: Conclude remarks. Rev Neurol 1995;23:1027-1032.

4. Unterharnscheidt, F. A neurologist's reflections on boxing, IV: Late and permanent brain damage. Rev Neurol 1995;23:1013-1026.

5. Unterharnscheidt, F. A neurologist's reflections on boxing, III: Vascular injuries. Rev Neurol 1995;23:847-855.

6. Unterharnscheidt, F. A neurologist's reflections on boxing, II: Acute and chronic clinical findings secondary to central nervous system damage. Rev Neurol 1995;23:833-846.

7. Moseley IF. The neuroimaging evidence for chronic brain damage due to boxing. Neuroradiology 2000;42:1-8.

8. Constantoyannis C, Partheni M. Fatal head injury from boxing: a case report from Greece. Br J Sports Med 2004;38:78-79.

9. Geddes JF, Vowles GH, Nicoll JA, et al. Neuronal cytoskeletal changes are an early consequence of repetitive head injury. Acta Neuropathol (Berl) 1999;98:171-178.

10. Jordan BD, et al. CT of 338 active professional boxers. Radiology 1992;185:509-512.

11. Powell JW. Cerebral concussion: Causes, effects, and risks in sports. J Athl Train 2001;36:307-311.

12. Roberts GW, Allsop D, Bruton C, The occult aftermath of boxing. J Neurol Neurosurg Psychiatry 1990;53:373-378.

13. Schmidt ML, et al. Tau isoform profile and phosphorylation state in dementia pugilistica recapitulate Alzheimer's disease. Acta Neuropathol (Berl) 2001;101:518-524.

14. Zhang L, et al. Increased diffusion in the brain of professional boxers: a preclinical sign of traumatic brain injury? AJNR Am J Neuroradiol 2003;24:52-57.

15. Bodensteiner JB, Schaefer GB. Dementia pugilistica and cavum septi pellucidi: born to box? Sports Med 1997;24:361-365.

16. Jordan BD. Chronic traumatic brain injury associated with boxing. Semin Neurol 2000;20:179-185.

17. Mendez, MF. The neuropsychiatric aspects of boxing. Int J Psychiatry Med 1995;25:249-262.

18. Ross RT and Ochsner MG Jr. Acute intracranial boxing-related injuries in US Marine Corps recruits: Report of two cases. Mil Med 1999;164:68-70.

19. Zazryn TR, Finch CF, McCrory P. A 16-year study of injuries to professional boxers in the state of Victoria, Australia. Br J Sports Med 2003;37:321-324.

20. Hazar M, et al. Ophthalmological findings in elite amateur Turkish boxers. Br J Sports Med 2002;36:428-430.

21. Noble, C. Hand injuries in boxing. Am J Sports Med 1987;15:342-346.

22. Ooi A, et al. Boxer's pericardium. Eur J Cardiothorac Surg 2003;24:1043-1045.

23. Bents RT, Metz JP, Topper SM. Traumatic extensor tendon dislocation in a boxer: A case study. Med Sci Sports Exerc 2003;35:1645-1647.

24. Erlanger DM, et al. Neuropsychology of sports-related head injury: Dementia pugilistica to post concussion syndrome. Clin Neuropsychol 1999;13:193-209.

25. Gennarelli TA, Graham DI. Neuropathology of the head injuries. Semin Clin Neuropsychiatry 1998;3:160-175.

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27. Kelly JP. Traumatic brain injury and concussion in sports. JAMA 1999;282:989-991.

28. Matser JT, et al. Chronic traumatic brain injury in professional soccer players. Neurology 1998;51:791-796.

29. Meythaler JM, et al. Current concepts: diffuse axonal injury-associated traumatic brain injury. Arch Phys Med Rehabil 2001;82:1461-1471.

30. Parker RS, Rosenblum A. IQ loss and emotional dysfunctions after mild head injury incurred in a motor vehicle accident. J Clin Psychol 1996;52:32-43.

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Life is as dear to a mute creature as it is to man. Just as one wants
happiness and fears pain, just as one wants to live and not die, so do
other creatures.
--The Dalai Lama

Gregory H. Bledsoe, MD, MPH, Guohua Li, MD, DRPH, and Fred Levy, MD, JD

From the Department of Emergency Medicine, the Johns Hopkins University School of Medicine, Baltimore, Maryland.

Reprint requests to Dr. Gregory H. Bledsoe, Department of Emergency Medicine, The Johns Hopkins University School of Medicine, 600 North Wolfe Street, Marburg B-186, Baltimore, MD 21287. E-mail:[e-mail]

Accepted June 28, 2005.

RELATED ARTICLE: Key Points

* The overall incidence of boxing injuries was 17.1 per 100 boxer-matches or 3.4 per 100 boxer-rounds.

* Facial lacerations were the most common injury followed by injuries to the hand, eye, and nose.

* Although once rare, female professional boxing matches now make up almost 10% of professional matches in Nevada.

* Male boxers were significantly more likely to receive injuries compared with female boxers, and male boxing matches demonstrated a significantly higher rate of knockouts and technical knockouts compared with female boxing matches.

Table 1. Frequencies of boxing injuries to professional boxers: Nevada,
September 2001 to March 2003

                            Male                  Female
                        No.       %             No.      %

Eye                      27        14.21        1         25.00
Facial laceration        97        51.05        2         50.00
Nose                     10         5.26        0          0.00
Hand                     33        17.37        0          0.00
Ear                       3         1.58        0          0.00
Mouth                     2         1.05        0          0.00
Jaw                       3         1.58        1         25.00
Shoulder                  6         3.16        0          0.00
Elbow                     2         1.05        0          0.00
Ankle                     2         1.05        0          0.00
Foot                      1         0.53        0          0.00
Chest                     3         1.58        0          0.00
Abdomen                   1         0.53        0          0.00
Shoulder and elbow        1         0.53        0          0.00
Total                   191       100.00        4        100.00

Up to four injuries for each boxer were recorded.

Table 2. Frequency of TKO/KO in male boxing matches compared with female
boxing matches (a)

1 = Male
0 = Female     TKO/KO     Other       Total

0               20.0       62.0         82
                24.4       75.6        100.0
                 3.9       11.6          7.8
1              496        470          966
                51.4       48.7        100.0
                96.1       88.4         92.2
Total          516        532         1048
                49.2       50.8        100.0
               100.0      100.0        100.0

Pearson [chi square] = 21.973, P < 0.0001.
(a) TKO, technical knockout: KO, knockout.

Table 3. Incidence rate of injury by boxer characteristics and match
outcome

                                  No. of           No. of    No. of
                                  boxers injured   matches   rounds

Age (yr)*
< 25                                  52             394      1,699
25-34                                 73             346      1,889
[greater than or equal to] 35         53             306      1,662
Sex
  Male                               175             966      4,906
  Female                               4              82        348
Weight
  [less than or equal to] 130         39             251      1,297
  131-150                             54             302      1,538
  151-185                             42             216      1,095
  [greater than or equal to] 186      44             279      1,324
Outcome
  Win                                 55             493      2,459
  Loss                               108             493      2,459
  Draw or no conclusion               16              62        336
Type of decisions
  Knockout                            76             516      1,734
  Other decisions                    103             532      3,520

                                  Rate per     P      Rate per    P
                                  100 matches  value  100 rounds  value

Age (yr)*
< 25                                 13.20     0.017     3.06     0.356
25-34                                21.10               3.86
[greater than or equal to] 35        17.32               3.19
Sex
  Male                               18.12     0.002     3.57     0.013
  Female                              4.88               1.15
Weight
  [less than or equal to] 130        15.54     0.618     3.01     0.586
  131-150                            17.88               3.51
  151-185                            19.44               3.84
  [greater than or equal to] 186     15.77               3.32
Outcome
  Win                                11.16     0.000     2.24     0.000
  Loss                               21.91               4.39
  Draw or no conclusion              25.81               4.76
Type of decisions
  Knockout                           14.73     0.046     4.38     0.007
  Other decisions                    19.36               2.93

*Two boxers included in this study did not have age information.

Types of Injuries to Professional Boxers Nevada, September 2001-March
2003

OTHER            13%
EYE              14%
FACIAL LAC       51%
NOSE INJ          5%
HAND INJ         17%

Fig. 2 Types of injuries to professional boxers: Nevada, September 2001
to March 2003.

Note: Table made from pie chart.

Table 4. Injury incidence rates by match outcome and type of decision

              No. of                Injury rate
              injured    No. of     per 100
Outcome       boxers     rounds     rounds         P value

Win
  Knockout    18          867        2.08          0.776
  Other       37         1592        2.32
Loss
  Knockout    58          867        6.69          0.000
  Other       50         1592        3.14