2Epidemiologic studies of tennis injuries Presented by: Rahman Sheikhhoseini PHD Candidates in Sport Injuries and corrective Exercises Tehran University Oct-2012
3IntroductionTruly a global sport, with tens of millions of yearly participants worldwide.Over 200 nations having an association with the International Tennis Federation.Reintroduced as a full medal sport beginning with the 1988 Summer Olympic Games in Seoul, South Korea (BJSM).The most common types of injury in tennis players of all ages are muscle and ligament strains or sprains secondary to overuse (MSK).In high-level players under 18 years of age, injury rates have been estimated to be anywhere from 2 to 20 injuries per 1000 h of tennis playedPluim et al, in a comprehensive meta-analysis across all player levels, reported tennis-injury incidence as ranging from 0.04 to 3.0 injuries per 1000 h playedAbrams 2012
4INJURY LOCATION AND CHRONICITY Data show that most tennis injuries occur in the lower extremity (31%–67%), followed by the upper extremity (20%–49%) and lastly, the trunk (3%– 21%).The most frequently injured parts of the lower extremity were the ankle and thigh, with ankle sprains being the most common specifi c injury.Upper extremity injuries most commonly involved the elbow and shoulder, with lateral epicondylitis being prevalent.Abrams 2012
5INJURY LOCATION AND CHRONICITY Acute injuries commonly occur in the lower extremity while chronic injuries most often manifest themselves in the upper extremity and trunk.In a 6-year injury-surveillance study, Boy’s National Championship, the prevalence of injury was 21.1%, with the back being the most common anatomic site of injury (3.4%), followed by the thigh, shoulder and ankleThe rate of acute injures to the lower extremity, however, was nearly twice that of upper extremity and trunk, with acute ankle injuries demonstrating a prevalence of 2.4%Injuries in the younger players are usually not long-standing, and the overuse (chronic) problems seen in the older players, such as patellar tendinosis and tennis elbow, are less common in younger playersAbrams 2012
7In conclusion:Age is a dominant factorthe incidence rate was much higher for the over 35 age group.Gruchow suggests that it is a "degenerative disease".
8In their study too:A questionnaire was constructed after discussion with players (interview)Men's teams in two tennis leagues (Division 1 and 2) in a large conurbation were surveyed.The total number of players surveyed was 74 of which 26 reported that they suffered or had suffered from tennis elbow.
9In conclusion:The incidence rate is high, and the severity of the injury is a serious problem to local league tennis players.
10Injury surveillance at the USTA Boys’ Tennis Championship: A 6-yr study Hutchinson MR, Laprade RF, Burnett QM, Moss R, Terpstra J Med & Sci in Spor & Exer, 1995,Subjects: USTA Boys’ Tennis Championship from , Definition: All injuries that required physical or medical assistance Athletes were evaluated and injuries documented by an athletic trainer and referred to the tournament physician if needed. The court surface was Dynacourt Each injuries was classified as either recurrent or new. Prevalence was defined as the number of new and recurrent injuries that required medical evaluation or treatment. The injuries were classified to anatomic regions: upper & lower Exts and trunk. Injury subtypes (9): strain, sprain, contusion, abrasion, laceration, fracture, dislocation or subluxation, inflammation and miscellaneous. Specific injuries with eponyms associated with tennis were also recorded (tennis: shoulder, elbow, leg, toe).
11Statistical analysisBonferroni fix for simultaneous inference: to compare the incidence and prevalence of lower extremity injuries to that of upper extremity and central region. Contingency task analysis for independence (Chi square) Simple linear regressions: to assess trends in incidence and prevalence of injuries over the years as well as the actual number of athletes sustaining injuries. Year: independent variable Number of injuries or injured athletes: dependent variable
14The incidence and prevalence of lower extremity injuries was approximately twice that of upper extremity injuries and the difference was statistically significant but there were no significant difference between upper extremity and central injuries. Injury trends during the years studied (NS)
15In Review:Injuries to the back, neck, and groin occur at a number roughly equal to that of upper extremity problems (shoulder, elbow and wrist). Overall, leg injuries (hamstring, knee and ankle) occur approximately twice as often as upper extremity injuries.The most common types of injury in young tennis players are overuse injuries.
17Injuries with tennis eponyms such as tennis elbow, tennis leg, tennis shoulder and tennis toe are less commonly seen in the young tennis player.
18SummaryThe shoulder is the most commonly affected part of the upper extremity.In contrast to older player with rotator cuff impingement and degenerative changes (even possibly a tear), the young player’s symptoms are more commonly secondary to instability of the glenohumeral joint.Traction apophysitis of the shoulder is similar to Osgood- Schlatter’s disease of the knee, at the insertion of the supraspinatus muscle into the greater tuberosity.Slipped capital humeral epiphysis occurs secondary to shear and distraction caused by rotational forces about the shoulderTennis shoulder refers to a drooping internally rotated shoulder caused by long term overhead arm use contributing to generalised laxity of the shoulder capsule and musculature.Elbow: Both lateral epicondylitis (tennis elbow) and medial epicondylitis have been described in young tennis players.Tendinitis of the wrist: Wrist extensors are most frequently involved but flexor tendons may be involved as well.
19Participants: In 2001, all the official junior tournaments of the Brazilian Tennis Confederation were catalogued to take part in this studyIn total, 13 tournaments, 2,307 games, 4,602 sets and 40,576 games were played, in male and female categories, with ages ranging from 10 to 18 years.A total of 258 athletes participated in this circuit
20MethodsThe medical staff consisted of one doctor and two physiotherapists151 (58.1% of all athletes) sought medical assistance: 105 males (69.5%) males and 46 females (30.5%)The medical questionnaire included: tournament, date, club, city, state, age, name, lesion, assistance on court or out-clinic and whether or not the player retired. tournament, date, club, city, state, age, name, injury, assistance on-court or out-clinic, and whether or not the player retired.medical assistance any consultation and/or treatment given to an athlete during a tournament on-site.No hospital care was required for athletes after medical consultation.The tournament medical department was the only place for medical consultations.
21Statistical analysisDescriptive analyses: absolute and relative frequency (%) for qualitative.The incidence of assistance per match was calculated for each age category by dividing the number of injuries by the number of matches during the season.The same evaluation was applied for incidence of assistance per set and game.
22Results185 medical evaluations were performed on 151 tennis players. Medical assistance was provided on court 83 times (29.6%), at the medical department 185 times (66.1%), and in both locations (due to the same clinical complaint) on 12 occasions (4.3%). The 151 athletes received 1 to 6 medical evaluations during tournaments, the mean being 1.8 evaluations per athlete.
25ConclusionWe believe that older athletes have been exposed to a greater load of training and games since, at this age, many athletes take part in national tournaments, aiming for a professional career (or are currently participating in professional tournaments).
27A systematic search of published reports Articles published since The following electronic databases were explored: Pubmed (from 1966 to October 2005), Embase (from 1989 to October 2005), and Cumulative Index to Nursing and Allied Health Literature (CINAHL) (from 1982 to October 2005).search terms: ‘‘injury’’, ‘‘injuries’’, ‘‘prevalence’’, ‘‘incidence’’, ‘‘incidence density’’, ‘‘proportion’’, ‘‘distribution’’, ‘population’’, ‘‘aetiology’’, ‘‘etiology’’, ‘‘mechanism’’, ‘‘risk factor’’, ‘‘risk factors’’, ‘‘prevention’’ and ‘‘intervention’’. These terms were combined with ‘‘tennis’’.
28MethodologyInclusion criteria: they must contain data on tennis injuries; they must investigate the frequency of tennis injuries, the aetiology (for example, risk factors) of tennis injuries, the efficacy of prevention strategies, or a combination of these purposes; and they must have been published in English, German, or Dutch.Exclusion criteria: studies focusing on treatment and literature reviews.Studies classification: case reports, laboratory studies, descriptive epidemiological studies, analytic epidemiological studies, or intervention/prevention trials.In the Pubmed, Embase, and Cinahl databases resulted in, respectively, 1368, 1617, and 2460 potentially relevant hitsThe titles and abstracts were read and, if considered relevant, selected by two persons (BMP and JBS).39 case reports, 49 laboratory studies, 28 descriptive epidemiological studies, three analytic epidemiological studies, and no intervention study
32ResultsInjury incidence Injury incidence varied from 0.05 to 2.9 injuries per player per year. Per hour of play, the reported incidence varied from 0.04 injuries/1000 hours to 3.0 injuries/1000 hours. Incidence and prevalence rates for tennis elbow were quite high, with reported incidence varying from 9% to 35% and prevalence varying from 14% to 41%. Injury type Four of six studies reported more acute than chronic injuries. Most acute injuries occurred in the lower extremities Most chronic injuries were located in the upper extremities. Injuries to the trunk comprised 5% to 25% of all injuries.
33ResultsGender differences Lanese RR injuries per 1000 hours were recorded for male tennis players versus 1.0 injury per 1000 hours in female (p=0.37). Sallis et al 2001, 18–22 year old tennis players, The incidence was 0.46 injuries per male player per year and 0.42 injuries per female player per year.(NS) Hutchinson et al 1995, no significant difference in the overall rate of injury Winge et al 1989, found a higher injury rate in men (2.7 injuries per 1000 hours) than in women (1.1 injuries per 1000 hours). (P<0.05) Age Injury risk in tennis gradually increase with age, from 0.01 injuries per player per year in the 6–12 year age group to 0.5 injuries per player per year in those over 75 years of age. An increased incidence with age was consistently shown for tennis elbow
34resultsLevel of play Baxter-Jones et al 1993, elite young athletes. They found that performance success was significantly related to injury rate. Jayanthi et al 2005, Despite trends, there were no statistical differences in overall injury incidence and prevalence rates across all skill levels. Volume of play Gruchow et al 1979, Increased playing time was associated with increased incidence of new cases of tennis elbow in recreational players playing more than two hours a day versus those playing less than two hours a day. Jayanthi et al 2005,Total incidence and prevalence of all tennis related injuries was not different among recreational players who played less than four hours a week, four to six hours a week, or more than six hours a week.
35Study design Incidence: quantifies the number of new injuries that develop in a population of individuals at risk during a specific time interval. A retrospective cohort study design was instituted to determine stress fracture incidence and distribution in elite tennis players
36SubjectsPlayers designated by the Argentine Tennis Association for medical care at the High Performance National Training Centre during a two year period (2003/2004). Top ranked national players, male and female, professionals and juniors. Inclusion criteria: age between 13 and 35 years; girls had to be post- menarcheal; and no disease or drug treatment likely to influence bone density. The cohort included 145 tennis players (95 male, 50 female). Sixteen were excluded from the analysis, representing an overall attrition rate of 10.9%. Of these exclusions, four retired from regular tennis training, two moved to another country, two girls had primary amenorrhoea, one player had type I diabetes which is potentially linked to osteopenia, and seven did not attend scheduled medical follow up visits. The final study population included 139 elite tennis players (mean (SD) age, 20.0 (5.0) years; 91 male, 48 female). Eighty players (57.5%) were ‘‘professionals’’ (over 18 years of age) and 59 (42.4%) were ‘‘juniors’’ (under 18).
37ProceduresApproval from ethics committee After the 24 month period, documented medical records reviewed for all confirmed clinical cases of stress fracture, regardless of anatomical location. Diagnostic criteria: No history of related trauma; Pain associated with exercise and relieved by rest; localised bony tenderness, pain on bone loading or on pain- eliciting manoeuvres; Radiographic and magnetic resonance imaging confirmation of diagnosis; Minimum follow up six months after returning to sports
38ProceduresAll players with suspected diagnosis of stress fracture were evaluated with conventional radiographs and magnetic resonance imaging (MRI). Radiographs were considered positive if they showed fracture lines, periosteal reaction, medullar sclerosis, or callus formation. MRI is considered the gold standard for stress fracture diagnosis Stress fractures were classified according to the guidelines of Arendt et al ‘‘low risk stress fracture’’ and ‘‘high risk stress fracture’’ were determined according to anatomical site, time to healing, and propensity to union. Time to return to sport was obtained from medical records and checked for all patients.
42ResultsFour women and 11 men of the total of 139 study participants sustained stress fractures. Three women suffered bilateral injuries. Consequently, 15 participants sustained 18 stress fractures. Overall case incidence of 12.9% in elite tennis players. The incidence of more than one injury was 2.9%. No significant difference between the male rate and the female rate (p=0.451, Fisher’s exact test). The age of injured players averaged 17.3 (4.0) years. Stress fracture incidence was significantly higher in ‘‘junior’’ players than in ‘professionals’’ (Fisher’s exact test). Radiographs were initially negative in 14 cases (77.7%). One was grade 1 (5.5%), none were grade 2, nine were grade 3 (50%), and eight were grade 4 (44.4%). Time required to return to sports averaged 15.1 (8.4) weeks
43Design: The International Tennis Federation facilitated a meeting of 11 experts from seven countries representing a range of tennis stakeholders. Using a mixed methods consensus approach, key issues related to definitions, methodology and implementation were discussed and voted on by the group during a structured 1-day meeting. Following this meeting, two members of the group collaborated to produce a draft statement, based on the group discussions and voting outcomes. Three revisions were prepared and circulated for comment before the final consensus statement was produced
44DefinitionsMedical condition (injury/illness) Any physical or psychological complaint or manifestation sustained by a player that results from a tennis match or tennis training, irrespective of the need for medical attention or time loss from tennis activities. The term ‘‘medical condition’’ was adopted in this statement rather than ‘‘injury,’’ in order to reflect the desire to collect information on both injuries and illnesses. The term ‘‘manifestation’’ was added to the term ‘‘complaint,’’ as players are not always aware that they have an ailment, precipitating a complaint, even though the player may have external signs and symptoms that would alert a medical/healthcare practitioner to a condition such as heat-related illness. Finally, the term ‘‘psychological’’ was added to encompass the full range of conditions sustained by tennis players—for example, burn-out.
45DefinitionsRecurrent medical condition A medical condition of the same type and at the same site linked to an index medical condition and which occurs after a player’s return to full participation from the index medical condition. Injuries such as contusions and lacerations should not be recorded as recurrent injuries, as they are unlikely to be related to a previous injury. Repeat episodes of illnesses such as skin infections, exercise induced asthma, arrhythmias and upper respiratory tract infections should be recorded as recurrences.
46DefinitionsSeverity of medical condition The number of days that have elapsed from the date of onset of the medical condition to the date of the player’s return to full participation in tennis training and availability for match play. The day on which a medical condition first occurs does not count towards the severity of the condition. This issue is particularly important in tennis, as it is not unusual for a player to retire from a doubles match due to a medical condition but to play in a singles match later on the same day or on the following day. A ‘‘career-ending’’ medical condition is one that leads to a player’s retirement from tennis at the standard played at the time of sustaining the condition.
47DefinitionsClassification of medical conditions Whenever possible, a qualified medical/healthcare practitioner should provide a written diagnosis of each condition or use sport-specific codes, such as the Orchard, or University of Calgary, coding systems. In addition to recording whether a condition is an index or a recurrent condition, medical conditions should also be classified according to their mode of onset, body location and side and type. Acute and gradual-onset condition An acute-onset: resulting from a specific, identifiable event or when there is a sudden onset of (relatively severe) pain or disability. A gradual-onset: condition that manifests itself over a period of time, or when there is a gradual increase in the intensity of pain or disability, without a single, identifiable event being responsible for the condition.
50DefinitionsExposure Match Exposure: Play (including on-court warm up) between competing players. Any medical condition sustained during off-court warm-up or cool down should be recorded as a training condition. Training exposure: Individual physical activities that are aimed at maintaining or improving a player’s tennis skills or physical condition. The off-court warm-up/cool down period before/after a match should be recorded as training exposure.
51DefinitionsRecording information Studies should be approved by a recognised institutional ethics committee. Studies should normally follow a prospective, cohort design, as this approach reduces errors associated with information recall. Standardised data-collection forms Security of data Player baseline information form Baseline information required in most surveillance studies should include the player’s study reference number, age, gender, height, body mass, dominant arm and use of single or doublehanded backhand and forehand strokes. It would normally be appropriate to also record standard of play and, in the case of studies among professional tennis players, to record the player’s world ranking.
52DefinitionsMedical condition report form must include: Player’s study reference number, date of condition, whether the condition was sustained during match play or training, the Type of match (singles, doubles, mixed), the type of court surface played on (clay, hard, grass, indoor), information Describing the circumstances leading to the condition and the date of the player’s return to full participation. The nature of the condition (acute or gradual onset; body location, type and side; index or recurrence) A section should be provided to enable a specific diagnosis or classification code to be recorded; Free-text sections may be required for some studies if additional study-specific information is required.
53DefinitionsMatch and training exposure form This form should record the date, type and duration (hours and minutes) of each exposure together with the playing/training court surface used (clay, hard, grass, indoor). In many competitions, an umpire will record the duration of a match. Training exposure (hours and minutes), recorded separately for men and women and for singles, doubles and mixed doubles playing formats, should preferably be collected for each training session, but as a minimum it should be collected on a weekly basis.
54SubjectsA large tennis club in Stockholm with approximately 100 junior membersInclusion criteria: players from one tennis club, age between 12 and 18 years and playing tennis regularly, at least twice a week.Exclusion criteria: any injury that influences tennis play and physical performance at the start of the present study.75 players accepted.Ten players did not fulfill the inclusion criteria meaning that 65 tennis players (87%).Ten players dropped out within the first 3 months due to finishing playing tennis or playing less than twice a week (n = 5), change of tennis club (n = 3), or moving abroad (n = 2).
55Injuries and time of exposure for tennis At the start of the study, the players also filled out a questionnaire about personal data, left or right handed and dominant leg and possible previous injuries as well as the number of tennis hours per week. The tennis players received both oral and written information about the definition of injury and the injury reporting procedure. The tennis players were informed to contact the PI, if and in that case when they sustained an injury. The PI clinically examined the injured player to establish the diagnosis and to fill out an injury form. The players were asked to record the average hours per week of playing tennis including practice and matches. If the player did not play the usual average hours per week he (or she) contacted the principal investigator (PI). Furthermore, the PI contacted the players every third month to secure that the information about exposure to tennis and possible injuries related to tennis or other sports as well as that of illness or absence from tennis were correctly recorded. Time of exposure for tennis and injury incidence was based on these data during a 2- year survey.
56Injury definition and classification The definition of an injury was when the injury made it impossible for the tennis player to participate fully in regular tennis training or matches during at least one occasion, which is referred to as a time-loss injury. Recurrence: an injury of the same type and at the same site that occurred within 12 months after the index injury. Injury severity: the number of days from the date of injury to the date of returning to full participation in training or match. (Minimal = 1–3 days, mild = 4–7 days, moderate = 8–28 days, and severe = >28 days, end of career) Location of injury, type of injury and the diagnosis were based on the Orchard Sports Injury Classification System (OSICS).
57Statistical analysisDescriptive statistics To compare Boys and Girls, the Mann–Whitney U Test was used for continuous variables and the Chi square test was used for categorical variables. Injury incidence was calculated as the number of injuries per 1000 h exposure for tennis. A 95% CI for the incidence was calculated with the formula I ± 1.96*√I/R (I = incidence rate, R = total time at risk). All data were tested at a statistical significance level of 5% (P\0.05).
58ResultsTwelve players sustained three or more injuries during the 2-year study period. Seventy-six percent (n = 76) of the injuries occurred during practice and 24% during match. 30% of the players did not sustain any injury 45% did not sustain any lower extremity injury 65% did not sustain any upper extremity injury 75% did not sustain any trunk injury. There were no significant gender differences in terms of injury distribution.
65Main ResultsTennis elbow The overall incidence of lateral epicondylitis has been reported to be anywhere from 35% to 51% The rate of lateral epicondylitis is lower in those with two-handed backhands The development of lateral epicondylitis is likely more related to improper technique. Shoulder The percentage of tennis players at all levels with shoulder injuries in these studies ranged from 4% to 17%. 33% of the tennis players had radiographic signs of degenerative changes in the glenohumeral joint of their dominant arm versus only 11% of matched controls.
66PLAYER-SPECIFIC RISK FACTORS Age and sex Age: There was no significant correlation for tennis players across a variety of skill levels. rate of injury between men and women: the literature is fairly clear that there are no significant differences. Volume of play Volume of play is positively correlated with an increased injury rate. Skill level This study did not fi nd any signifi cant differences in rate of injury for multiple comparisons across a variety of skill levels. Although professional tennis players have improved technique and therefore a theoretically decreased risk of injury, their increased volume of play as compared with the nonprofessional may account for the similarity in injury rates between the two groups.
67PLAYER-SPECIFIC RISK FACTORS Racquet grip position Ulnar-sided injuries (extensor carpi ulnaris tendonitis and triangular fibrocartilage complex pathology) were significantly associated with western or semiwestern grips while radial-sided injuries (flexor carpi radialis tendonitis, DeQuervian’s tendinopathy and intersection syndrome) were more common in players with the eastern grip. Racquet properties Hennig et al showed that between different racket properties, increased racket head size as well as a higher resonance frequency of the racket was found to reduce arm vibration. There have been no studies, however, to determine the effect of arm vibration on injury rate or severity COURT SURFACE The RR of receiving treatment while playing on hard court as compared with grass was 0.8 (grass had a higher risk) while the RR between hard court and clay was 2.3 times (hard court had a higher risk). Risk of injury is lower on clay courts.