THE WESTERN JOURNAL OF MEDICINE
o SEPTEMBER 1990 o 153 * 3 319
slime capsule rendering the bacterium resistant to phagocy- Ride and Tie
tosis,17 and the production of toxins such as a-hemolysis'8 A Hybrid Sport With
or leukocidin,'9 which may inhibit neutrophil chemotaxis.
The killing of one but not both strains of S aureus as seen on Synergistic Potential for Injury
our patient's granulocyte bactericidal assay may imply dif-
ferences in strain virulence, although at present we lack the WILLIAM G. SAYRES, Jr, MD
diagnostic tools to explore this further. Salt Lake City
If the development of clinical bacterial infection involves
a balance between the virulence of organisms and adequacy THE COMPETITIVE SPORT of ride and tie has become popular in
of host defense mechanisms, a spectrum of disease pene- the past 15 to 20 years, especially in the Rockies and in
trance should be seen. This spectrum may include the elimi- California. Races generally cover 20 to 40 miles of hilly,
nation of bacteria without clinical illness (avirulent organ- often rough terrain. Each team consists of two runners and
ism or adequate defense mechanisms), indolent infection a horse. During a race, one runner rides ahead on horseback
(avirulent organism or impaired host defense mechanisms), for perhaps a mile, then dismounts, ties the horse to any-
or fulminant infection (virulent organism or adequate de- thing available, and continues the race on foot. The partner
fenses). We speculate that our patient had such an indolent reaches the horse, unties it, rides up to the first runner, and
course due to a combination of both an avirulent bacterium the two then switch. This process is repeated perhaps 20 to
and abnormalities of neutrophil number and neutrophil 30 times in a race.
bactericidal function. There are now more than 350 races, with an annual
We report the case of a patient with an indolent course of international championship. Races may contain 40 to 60
S aureus pneumonia, which has rarely been described in teams with varying levels of skill in both running and riding.
either immunosuppressed or normal hosts. The reasons for The sport offers a multitude of opportunities for injury. The
the indolent nature of bacterial infection are frequently un- trails are often steep and washed out, a race may ascend and
known, but the present case with the accompanying defects descend more than 2,400 m (8,000 ft) and race courses are
of neutrophil number and bactericidal function may ac- generally far removed from hospitals. The course is often
count for both the infection's insidious onset and delayed congested with both horses and runners, with the runners
rate of healing. This indolent course should not dissuade wearing standard road-racing attire and virtually no pro-
tective gear. Frequent mounting and dismounting stresses
physicians from the diagnosis of staphylococcal pneumonia tack and a rider's skills. The stresses of riding competitively
when positive culture evidence exists. over difficult terrain are exacerbated by physical exhaustion
REFERENCES from running on foot over half the distance of the race.
Chickering HT, Park JH: Staphylococcus aureus pneumonia. JAMA 1919;
2. Fisher AM, Trever RW, Curtin JA, et al: Staphylococcal pneumonia; a To better define the rate of injuries in the sport, I asked
review of 21 cases in adults. N Engl J Med 1958; 258:919-928
3. Hausmann W, Karlish AJ: Staphylococcal pneumonia in adults. Br Med J every applicant for the 1987 Park City (Utah) Ride and Tie
1956; 2:845-847 to fill out a questionnaire detailing injuries suffered while
4. Kuperman AS, Fernandez RB: Subacute staphylococcal pneumonia. Am
Rev Respir Dis 1970; 101:95-100
training and while competing. An injury was defined as
5. Gallis HA: Subacute staphylococcal pneumonia in a renal transplant recip-
being severe enough to cause a loss of training time. Com-
ient. Am Rev Respir Dis 1975; 112:109-112 petitors were asked to list how many injuries they had sus-
6. Breedveld FC, van den Barselaar MT, Leigh PCJ, et al: tained and whether the injuries had resulted from training
intracellular killing by polymorphonuclear cells from patients Phagocytosis
arthritis and Felty's syndrome. Arthritis Rheum 1985; 28:395-404
with rheumatoid or from competition. They were asked to describe their inju-
7. Gupta RC, Laforce FM, Mills DM: Polymorphonuclear leukocyte inclu- ries and how they were sustained. Demographic details
sions and impaired bacterial killing in patients with Felty's syndrome. J Lab Clin were also included in this survey. To follow up on these data,
Med 1976; 88:183-193 I interviewed by telephone the race directors of six well-
8. Chiu PL, Davis P, Wong K, et al: Superoxide production in neutrophils of recognized races, including the international champion-
patients with rheumatoid arthritis and Felty's syndrome. J Rheumatol 1983; ship. Details of any recalled accidents occurring over the
9. Harbeck RJ, Hoffman AA, Redecker S, et al: The isolation and functional past ten years were recorded.
activity of polymorphonuclear leukocytes and lymphocytes separated from
whole blood on a single Percoll density gradient. Clin Immunol Immunopathol
1982; 23:682-690 Results
10. Douglas SD, Lahav M, Fudenberg HH: A reversible neutrophil bacteri- Only 32 of 60 competitors completed the questionnaire
cidal defect associated with a mixed cryoglobulin. Am J Med 1970; 49:274-280 in full. The results are listed in Tables 1 and 2. The ages of
11. Whimbey E, Kiehn TE, Brannon P, et al: Clinical significance of colony
counts in immunocompromised patients with Staphylococcus aureus bacteremia. competitors ranged from 15 to 55 with most being between
J Infect Dis 1987; 155:1328-1330 31 and 50. There were slightly more men than women. Most
12. Sickles EA, Greene WH, Wiernik PH: Clinical presentation of infection in respondents were both experienced runners and riders. Of
granulocytopenic patients. Arch Intern Med 1975; 135:715-719 the 32 respondents, 26 stated that they trained at least 6
13. Press OW, Ramsey PG, Larson EB, et al: Hickman catheter infections in
patients with malignancies. Medicine (Baltimore) 1984; 63:189-200 months and often 12 months per year. In training, most ran
14. Pincus SH, Boxer LA, Stossel TP: Chronic neutropenia in childhood- less than 64 km (40 mi) a week, and 9 of the 32 did most of
Analysis of 16 cases and a review of the literature. Am J Med 1976; 61:849-861 the riding. This would suggest that one person, perhaps the
15. Thorne C, Urowitz MB: Long-term outcome in Felty's syndrome. Ann owner of the horse, spent the most training time on horse-
Rheum Dis 1982; 41:486-489
16. Spivak JL: Felty's syndrome: An analytical review. Johns Hopkins Med J back.
17. Lee JC, Betley MJ, Hopkins CA, et al: Virulence studies in mice of trans- (Sayres WG Jr: Ride and tie-A hybrid sport with synergistic potential
poson-induced mutants of Staphylococcus aureus differing in capsule size. J
Infect Dis 1987; 156:741-750 for injury. West J Med 1990 Sep; 153:319-321)
18. Vann JM, Proctor RA: Cytotoxic effects of ingested Staphylococcus au- From the Department of Family and Preventive Medicine, University of Utah
reus on bovine endothelial cells: Role of S aureus a-hemolysin. Microb Pathog School of Medicine, Salt Lake City.
1988; 4:443-453 Reprint requests to William G. Sayres, Jr, MD, Department of Family and
19. Shibl AM: Influence of subinhibitory concentrations of antibiotics on Preventive Medicine, University of Utah School of Medicine, 50 N Medical Dr,
virulence of staphylococci. Rev Infect Dis 1987; 9:704-711 Salt Lake City, UT 84132.
320 ALERTS, NOTICES, AND CASE REPORTS
A total of 14 competitors (44%) reported being injured popular ride-and-tie races. These races have been run from
severely enough during training to lose training time, with 9 5 to 15 times, with an average of 30 to 60 teams per race. The
(28%) listing more than one injury. Of the 32, 6 (19%) organizers of the international championship in Santa Cruz,
reported serious injuries sustained during competition. Be- California, were also contacted. At least ten highly competi-
cause most teams compete only once or twice during the tive championship races have been held, with an average of
year, this would seem a high percentage. There was no dif- more than 60 teams per race. Retrospective anecdotal data
ference between men and women in the number of injuries from approximately 49 races were available.
reported. Few injuries were noted by the race directors, and these
The 29 reported injuries included a skull fracture, a clav- followed the pattern reported for horse-riding injuries in
icle fracture, and two rib fractures. These accounted for a general: an open fracture of the tibia and fibula, a foot
notable 13% of reported injuries. Superficial cuts and abra- fracture, and four closed-head injuries, one of which re-
sions were the most commonly reported injuries. Others, quired hospital admission. Three cases of heat exhaustion
primarily musculoskeletal, are listed in Table 2. were reported. Organizers of races with a physician on hand
I also contacted by telephone the race directors of five reported more injuries than those with emergency medical
technicians, suggesting a bias in reporting. Race directors'
TABLE 1.-Experience and Injuries in reports differed from anecdotal reports by competitors, who
Ride-and-Tie Competitors reported more frequent and more serious injuries.
Experience, Training, and Injuries No. Ride and tie can be seen as a hybrid of endurance riding
Age, yr and mountain running, both popular sports in the West.
11-20. 3 This survey shows that more serious injuries result from
..... 8 riding than from running. The three cases of heat exhaus-
.............. . 18 tion that were reported occurred on a low-altitude course in
41-50. 7 mid-August. In general, races are held in relatively cool
55. ....................... . ..................
.. .. 1 mountain environments, where the risk of heat exhaustion
Sex is generally low.
Male.....................................20 The scientific literature associated with horse-riding in-
Female .. 12
Running experience, yr
juries is devoted primarily to English-style riding, which
includes hunter-jumper, dressage, and steeplechase riding.
3-5 ............................... 3 There is no published information on western-style riding,
............ 24 which includes "western pleasure," work-related riding,
NA ...................................... 2 and some endurance riding. Riding techniques, tack, breeds
Riding experience, yr of horses, terrain, and competitive activities all differ be-
0-2 ......................... 5 tween western riding and its English counterpart. With few
3-5 ...............4..................... 4 exceptions, ride-and-tie racers ride western, and therefore
5-10 ... 19 the results of existing studies to this sport must be applied
NA.......................................4 with caution.
Training, mo The severity of horse-related accidents is supported by
0-2 ............................. 1 data from the National Electronic Injury Surveillance Sys-
3-5 ....... 4 tem of the Consumer Safety Commission from 1979 to 1981:
2 6................................. 26 105 horse-related deaths were reported from emergency de-
NA .... 1 partments across the country. Accounting for unreported
Weekly training, running, km (mi) cases, it was estimated that from 217 to 257 deaths may
:548 (30) ...........,,,.,,... 13 have occurred from equestrian accidents during that per-
50-64(31-40) ........... 10 iod. In 1979 alone there were an estimated 31,488 horse-
66-80(41-50) ........7............ 7 related injuries leading to 3,558 hospital admissions.' In the
..... ....... ....... ....... ...... 2
1973 to 1974 national hunt season in England, there were
Weekly training, riding, km (mi) more than 237 recorded injuries, including 27 head injuries,
t48(30) ........ 11
50-64 (31-40) .............., 6
. . ..
122 fractures, and 80 minor injuries.2
66-80 (41-50) ............ 5 Head injuries consistently are the most severe of horse-
> 80 ............ 9
NA .............. 1 TABLE 2.-Injuries Sustained in 32 Ride-and-Tie Competitors
Training injuries, No.
0 ., 18 Competitors,
2-4 .......................... 4 Skull fracture ....1....1 ..... ,,.
5.7 .................. 1 Clavicle fracture .............
, .,,... 1
Rib fracture .......... 2
Competing injuries, No.
0. 26 Lower extremity ....................,,,.. 6
1 ... 3 Back ............. , .. 4
2-4 .....................................3 Knee pain . 5
5-7 ...................... 0 Plantar fascitis . 1
8. 0 Superficial abrasions . 9
NA not answered
WESTERN JOURNAL OF MEDICINE o SEPTEMBER 1990
THETHE~ * 153 * 3 321
related injuries.3'4 A ten-year review of death certificates in low for a rapid changing of the helmets during the ride
South Australia revealed 18 horse-related deaths, with 13 while sacrificing little time. Without making wearing hel-
due to head injuries.5 A one-year study in Sweden registered mets a requirement of the race, however, it is unlikely that
174 patients, 66 of whom were younger than 15 years. Of they will be used.
these riders, 67% had head injuries, and 11% of the head The diagnosis and treatment of head injuries has also
injuries resulted in "cerebral injury." Of these patients, 27 emerged as a weakness in race coverage. After falling from
reported persistent symptoms a year after the accident.6 the saddle not far from the start, a competitor at the na-
Head injuries were also found to be the most serious result tional championships was allowed to finish the race but
of riding accidents in a two-year study of 8,768 patients does not remember doing so.
with horse-related injuries at an Oxford, England, accident The perception of the safety of ride-and-tie races varies
service.' Persistent symptoms from such accidents were notably from the competitor to the race director. Race direc-
shown in a British study of five National Hunt jockeys with tors reported far fewer injuries than did competitors. With
posttraumatic encephalopathy.2 this mistaken perspective that ride-and-tie races are actu-
Wearing a helmet offers the most protection against ally safe competitions, race directors place little emphasis
head injuries from riding accidents. With the introduction on preventing human injuries. While an ambulance usually
of rules to ensure the use of approved helmets in Great stands by, riders are not required to wear protective cloth-
Britain, the incidence of serious head injuries reported in ing or helmets. Indeed, the horses and mules receive more
one study was cut in half.2 It is also well documented that medical attention than their human associates: at least two
riders frequently neglect to wear protective headgear. In or three compulsory veterinary examinations are common
another British study, half of head injury victims were not in a competition.
using helmets with safety straps.8 In 110 horse-related inju- Improved data collection, perhaps using the model of the
ries in Virginia, less than 20% of patients were wearing US Pony Club, would allow for a better analysis of injuries
protective headgear. Only one of the head-injured riders and documentation of preventive measures. This may be-
was wearing a helmet.9 Of 13 head injury-related deaths come possible with the formation of a national ride-and-tie
reported in South Australia, 9 of the victims were wearing association in 1988.
no headgear.5 In comparison to English riding, ride and tie would seem
Western riders rarely wear helmets, and ride-and-tie to be in the early days of its evolution. Instituting good
competitors virtually never do. documentation and injury prevention would go far towards
Fractures emerge as another serious result of horse-re- maintaining the health of its participants.
lated accidents. The rates of fractures ranged from 15% in REFERENCES
horse show injuries10 to 20% in a survey of United States 1. Bixby-Hammett DM: Accidents in equestrian sports. Am Fam Physician
Pony Club-related injuries,1" to 35% in riding accidents in 1987; 36:209-214
England,7 40% in fox-hunting accidents,12 and 44% among 2. Foster JB, Leiguarda R, Tilley PJ: Brain damage in National Hunt jockeys.
riders in Sweden.s Lancet 1976; 1:981-983
Horse-related injuries do not appear to be related to the 3. Bixby-Hammett DM: Head injuries in the equestrian sports. Physician
skill of the rider.8'12 Studies have shown that many acci- Sportsmed 1983; 11:82-86
dents occur in previously injured riders.'11'13 Swedish in- 4. Lloyd RG: Riding and other equestrian injuries-Considerable severity. Br
J Sports Med 1987; 21:22-24
vestigators reported that 35% of accident victims had had a 5. Pounder DJ: 'The grave yawns for the horsemen'-Equestrian deaths in
previous history of injury.6 South Australia 1973-1983. Med J Aust 1984; 141:632-635
Competitors in ride and tie are subject to the same risks 6. Gierup J, Larsson M, Lennquist S: Incidence and nature of horse-riding
as those riders encountered in previous studies of horse- injuries-A one-year prospective study. Acta Chir Scand 1976; 142:57-61
7. Barber HM: Horse-play: Survey of accidents with horses. Br Med J 1973;
riding accidents-head injuries and fractures in particular. 3:532-534
Although most injuries occur while training, the likelihood 8. Whitlock MR, Whitlock J, Johnston B: Equestrian injuries: A comparison
of injury is greatly increased during competition. Experi- of professional and amateur injuries in Berkshire. BrJ Sports Med 1987; 21:25-26
ence seems little related to accidents. 9. Grossman JA, Kulund DN, Miller CW, et al: Equestrian injuries-Results
of a prospective study. JAMA 1978; 240:1881-1882
Although some respondents to my survey reported over- 10. Lincoln E: Headgear could prevent some riding injuries. Physician
use injuries of the back and lower extremity, most injuries Sportsmed 1982; 10:29
were related to the horse-riding aspect of the sport. 11. Bixby-Hammett DM: Youth accidents with horses. Physician Sportsmed
The use of protective headgear is the most obvious first 1985; 13:105-117
step in preventing serious injuries in ride and tie. Because 12. Harrison CS: Fox hunting injuries in North America. Physician
Sportsmed 1984; 12:130-137
competitors run at least half the race, they may consider 13. Zaricznyj B, Shattuck LJ, Mast TA, et al: Sports-related injuries in school-
helmets cumbersome, but a quick-action buckle would al- aged children. Am J Sports Med 1980; 8:318-324