Clinical improvement after 6 weeks of eccentric exercise in patients with mid-portion Achilles ...

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Clinical improvement after 6 weeks of eccentric exercise in patients with mid-portion
Achilles tendinopathy - a randomized trial with 1-year follow-up.
Roos, Ewa; Engström, Mikael; Lagerquist, Annika; Söderberg, Bengt
Published in:
Scandinavian Journal of Medicine & Science in Sports
DOI:
10.1111/j.1600-0838.2004.378.x
2004
Link to publication
Citation for published version (APA):
Roos, E., Engström, M., Lagerquist, A., & Söderberg, B. (2004). Clinical improvement after 6 weeks of eccentric
exercise in patients with mid-portion Achilles tendinopathy - a randomized trial with 1-year follow-up.
Scandinavian Journal of Medicine & Science in Sports, 14(5), 286-295. https://doi.org/10.1111/j.1600-
0838.2004.378.x
Total number of authors:
4
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LUND UNIVERSITY
PO Box 117
221 00 Lund
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ScandJMedSciSports 2004: 14: 286–295 COPYRIGHT&BLACKWELLMUNKSGAARD2004
PrintedinDenmark.Allrightsreserved
DOI:10.1111/j.1600-0838.2004.00378.x
Clinical improvement after 6 weeks of eccentric exercise in
patients with mid-portion Achilles tendinopathy – a randomized
trial with 1-year follow-up
Ewa M. Roos1, Mikael Engstro¨m2, Annika Lagerquist3, Bengt So¨derberg2
1DepartmentofOrthopedics,LundUniversityHospital,SE-22185Lund,Sweden,2ScandinavianOrthopedicLaboratory,
Helsingborg,Sweden,3SportsMedicineClinic,Helsingborg,Sweden
Correspondingauthor:EwaRoos,PTPhD,DepartmentofOrthopedics,LundUniversityHospital,S-22185Lund,Sweden.
Tel: [phone], Fax: [phone], E-mail: [email protected]
Acceptedforpublication1December2003
Achilles tendinopathy is common and treatment with P50.001). The two groups treated with a night splint
eccentric exercises seems promising. We designed a also reported significant but less pain reduction than the
prospective randomized clinical trial to test the hypothesis eccentric group. Differences between all the three groups
thateccentriccalfmuscleexercisesreducepainandimprove were not significant. At 12 weeks, the eccentric group
functioninpatientswithAchillestendinopathy.Forty-four reported significantly less pain than the splint-only group
patients were recruited from primary care (mean age: 45 (P50.04).Morepatientsintheeccentricgroupthaninthe
years;23women;65%activeinsports)andrandomizedto splintgroupreturnedtosportafter12weeks.Weconclude
threetreatmentgroupsfor12weeks:eccentricexercises,a that eccentric exercises seem to reduce pain and improve
nightsplintoracombinationofbothtreatments.Painand functioninpatientswithAchillestendinopathy.Ourresults
function were evaluated at 6, 12, 26 and 52 weeks by the are in line with previous studies and strengthen the
FootandAnkleOutcomeScore.At6weeks,theeccentric recommendation thatpatients shouldundergoan eccentric
groupreportedasignificantpainreduction(27%compared exerciseprogrampriortoconsideringothertreatmentssuch
with baseline, P50.007) which lasted for 1 year (42%, assurgery.
Achilles tendinopathy is common, especially in because of tendinopathy, an inverse correlation
physically active people, and the incidence increases between reported success rate and methodological
with age (Kvist, 1994). Suggested etiological factors score was found: the better the result the study
include extrinsic factors such as training errors and reported the more methodological problems with
inappropriate footwear and intrinsic factors such as the study, indicating the need for more care-
inflexibility, weakness and malalignment. However, fully designed studies within this field (Tallon et al.,
as stated previously, very few controlled studies on 2001).
these issues are available (Almekinders & Temple, Theconceptofeccentricexercisesastreatmentfor
1998; McCrory et al., 1999). tendinopathy has been described by Stanish and
Treatment of Achilles tendinopathy is initially coworkers and is based on the belief that tendon
non-operative. Most commonly studied non-opera- injuries often occur during the eccentric phase
tive treatments include rest, equipment changes, of muscle work (Stanish et al., 1986, 2000). The
strength and flexibility exercises, anti-inflammatory mechanismsbehindtheeffectsofeccentricexerciseas
agents and corticosteroids. The results are not con- treatment of tendinopathy are largely unknown. It
clusive,andinaliteraturereviewfrom1998concern- hasbeensuggestedthateccentricexercisesmayeither
ing overall tendonitis, Almekinders and Temple directly affect tendon pathology or prepare the
suggested that we have to consider the possibility muscle for better function (Cook et al., 2002; Khan
thatcurrenttreatmentmaynotsignificantlyalterthe et al., 2003). Eccentric exercises have been shown
natural history (Almekinders & Temple, 1998). to have positive effects on Achilles tendinopathy
Alternative explanations to why the results were (Alfredson et al., 1998; Mafi et al., 2001; Silbernagel
not conclusive include Achilles tendinopathy being et al., 2001). However, only two of these trials were
of multi-factorial origin and thus one single treat- randomized and controlled (Mafi et al., 2001;
mentnotbeingpossible,andpoorstudydesign.Ina Silbernagel et al., 2001) and in one of them the
criticalanalysis ofstudiesofAchillestendonsurgery eccentric exercises were part of a treatment package
286
Eccentric exercises for Achilles tendinopathy
(Silbernagel et al., 2001). To aid clinical decision added because it was hypothesized that prolonged stretching
making and to establish evidence of an intervention possibly could reduce muscle soreness, a well-known side-
several randomized controlled trials with consistent effect of eccentric exercises, and thus result in a program
bettertoleratedbypatients.
results within different populations are needed.
The outcome was evaluated by a patient-administered
Prolonged stretching with the use of a night splint
questionnaireatbaseline andat6,12,26 and52 weeks after
is prescribed and believed to maintain passive initiationoftreatment.
dorsiflexion, reduce pain and morning stiffness ThestudyprotocolwasapprovedbytheEthicsCommittee
because of Achilles tendinopathy (Schepsis et al., attheMedicalFacultyatLundUniversity.
2002). Night splints are also used as treatment of
plantar fasciitis (Probe et al., 1999; Martin et al.,
2001;Berletetal.,2002).Toourknowledgetheeffect
of night splints on Achilles tendinopathy have not Eccentricexercise program
been studied. Eccentric calf-muscle exercises (3(cid:1)15 repetitions with
The objective of the present study was to straight and bent knee) were prescribed twice daily for 12
prospectively study the short- and long-term effects weeks as previously described by Alfredson et al. (1998).
In the study by Alfredson et al., the patients experienced
of eccentric exercises and prolonged stretching with
severe muscle soreness during the first weeks of exercise
theuseofanightsplintonpainandfunctionbecause
(H. Alfredson, 1998, personal communication). To possibly
of Achilles tendinopathy in subjects recruited from diminish this initial muscle soreness, the patients in the
primary care. current study were instructed to gradually increase the
numberofrepetitions:
Days1–2 1(cid:1)15repetitions
Materials and methods Days3–4 2(cid:1)15repetitions
Days5–7 3(cid:1)15repetitions
Patients
Patients 20–60 years of age seeking medical care within During the first week, the patients only did their exercises
primary care in Helsingborg, Sweden because of insidious with extended knee. During weeks 2–12, the patients were
onset of Achilles tendinopathy were candidates for inclusion instructed to perform 3(cid:1)15 repetitions with both extended
in the study. The activity level prior to the current problems and bent knees ateach exercise occasion. This gradual onset
shouldbeatleastequivalenttoheavyhouseholdwork,heavy wasnotusedbyAlfredsonetal.(1998).
yardworkandwalkingonevenground.Thepatientsshould One physical therapist instructed the patients how to
report at least moderate pain/problems when performing perform the exercises. The exercises were carried out in a
physical activities, and the duration of symptoms should be standingpositionwithfullbodyweightontheforefootandthe
more than 4 weeks. Patients who fulfilled these written ankle joint in plantar flexion. The patient lowered the heel
inclusion criteria were referred to one examiner who beneath the forefoot. During the eccentric part, the patient
randomized the patients by pulling an envelope from a box hadfullweightontheinjuredfoot,andduringtheconcentric
holding60randomlyorderedenvelopes,20foreachtreatment partonlythenon-injuredfootwasused(Figs1and2).When
group. The examiner also did a clinical examination and the patients could perform their exercise without discomfort
verified symptoms 2–6cm proximally of the insertion. To theywereinstructedtoincreasetheloadbyaddingbooksor
ensurethediagnosis,patientswithsymptomslocalizedatthe other weight to a backpack. Patients also received a written
insertionofthetendonwereexcluded. manualhowtoprogresstheintensityoftheexerciseprogram
including contact information for the therapist and instruc-
tions to call if they had any questions. After 1 week, the
patients saw the physical therapist to discuss possible
Studydesign
problems and to check-up how the program was performed.
The design was a randomized study with three treatment After 6 weeks, the therapist called the patients by phone to
groups for 12 weeks: eccentric exercises, night splint or a discusspossibleproblemswithprogressionoftheintensityof
combination of both treatments. The combined group was theprogram.
Fig. 1. Eccentric exercises with straight
knee.The affected leg(right) is marked.
287
Roos et al.
Fig. 2. Eccentric exercises with bent knee.
The affected leg (right) ismarked.
Nightsplint
Ananteriornightsplint,thoughttoreducemorningpainand
stiffness, holding the foot in 901 of dorsiflexion was used.
Maintaininga footposition ofneutral plantigrade, a3.2mm
thickness of Omega Plus (Northcoast Medical Inc., CA,
USA), a low-temperature thermoplastic, was draped directly
onto the anterior lower leg and foot of each patient. Each
template of material was 70mm wide and of length equal to
themeasurefromthetibialtuberositytothemetatarsalheads.
Reinforcement was applied at the level of the anterior ankle
crease prior to heating. Skin protection was afforded by
stockinette(Fig.3).Oncecooled,alinerof3mmlow-density
polyethylene was added, along with four Velcro straps
(Homecraft Ability One, Nottinghamshire, UK) for securing
thenightsplint.Thesewereplacedimmediatelyinferiortothe
tibialtuberosity,attheproximalmalleoli,thelevelofthemid-
tarsaljointandacrossthemetatarsalheads(Fig.4).
Fig. 4. Theanterior night splint.
Each patient was directed on proper application of the
orthosis and on its nighttime use only. Possible problems
whichmightbeencounteredwerealsodiscussed.
Anterior night splints are advantageous over posterior
ones, should the patient wish to get out of bed during the
night, they are able to walk without first removing the
orthosis. Also as a smaller surface area of the leg is covered
betterheatdissipationisexperiencedandthusledtocomfort.
Daily logs
To determine compliance with the treatments and possible
side-effects,thepatientskeptdailylogsthatwerereturnedat
6 and 12 weeks, respectively. Compliance was assessed on
a weekly basis. The eccentric exercise group was prescribed
exercise 14 times a week. Good compliance was defined as
reporting at least 75%, e.g., 10 exercise times a week.
Recommended use of the night splint was seven nights a
week. Similarly, good compliance was defined as using the
nightsplintatleast75%,e.g.,fivenightsaweek.Side-effects
(examples given included muscle soreness, bruising, sleep
Fig. 3. The anterior nightsplint. disturbances)werealsoevaluatedonaweeklybasis.
288
Eccentric exercises for Achilles tendinopathy
Outcomemeasures Apoweranalysiswascarriedoutpriortothestudy.Itwas
determined that totally 60 patients were needed to detect a
Footandankleoutcomescore
clinicallysignificantmeanscoredifferenceof10pointsinthe
Symptoms,functionandfootandankle-relatedqualityoflife FAOSsubscalepainbetweengroupswith80%powerandat
were evaluated by a mailed survey, the Foot and Ankle P50.05.
OutcomeScore(FAOS)(www.koos.nu).Aformalvalidation
has been carried out in subjects with lateral ankle ligament
injury(Roosetal.,2001).Thetest–retestreliabilitywashigh,
indicating the FAOS being an accurate measure with high Results
abilitytomeasurealsosmallchangesovertime.TheFAOSis Patients
anadaptationoftheKneeInjuryandOsteoarthritisOutcome
Score (KOOS) (Roos et al., 1998a,b) and assesses patient- From September 1998 to July 2001, 44 patients (23
relevant outcomes in five separate subscales: Pain, Other women) were recruited by 23 primary-care physi-
Symptoms, Activities of Daily Living (ADL), Sport and cians and referred to one examiner. Their mean age
RecreationFunction,andFootandAnkle-relatedQualityof
was 46 (range, 26–60 years), 65% were active in
Life.Painwasconsideredtheprimaryoutcome.Apercentage
sports prior to the current symptoms, 86% reported
score from 0 to 100 is calculated for each subscale, 100
representing the best possible score. For the KOOS, a 10% pain daily or always, while 14% reported having
scorechangeisconsideredtoindicateaclinicalchange(Roos weekly pain. The median symptom duration was 5.5
&Lohmander,2003).Asthesubjectsofthecurrentstudyare months (range, 1–180 months) and 86% reported
of similar age and activity level to the subjects evaluated by
having had symptoms for more than 3 months.
the KOOS, we decided to apply a 10% change to indicate a
Eighty-four percentreported aninsidiousonset.The
clinicalimprovementalsointhepresentstudy.
patients reporting a sudden onset had a median
symptom duration of 5 months. Sixty percent
Physicalactivitylevel
reported having tried other treatments previously,
Physical activity level was evaluated on a seven-grade scale often in combinations. The most common previous
from 0 to 6, 0 representing no household work, TV and
treatments were oral NSAIDs (n512), topical
readingandsixrepresentingcompetitivesports(Table1).This
NSAIDs (n510), shoe modifications (n510), rest
scalehaspreviouslybeenusedtoevaluatethephysicalactivity
level of young and middle-aged patients with post-traumatic (n59) and physical therapy (n58). One patient,
kneeosteoarthritis.Thereliabilityhasbeenfoundgood(Roos randomized to the eccentric exercise group, was
etal.,1999).Difficultyduringsportingactivitieswasassessed operated on twice because of Achilles tendinopathy.
on a five-point Likert scale (no, mild, moderate, severe,
There were no significant differences in sex, age,
extreme). For comparisons of difficulty between treatment
activity level, symptom duration or baseline status
groups,theanswerswerecategorizedintonoormilddifficulty
andmoderate-to-extremedifficulty. between the groups with one exception, patients
randomized to the splint group reported a signific-
antly better foot and ankle-related quality of life
at baseline (Table 2). Pain and swelling 2–6cm
Statistics
proximally of the Achilles tendon insertion was
To safely deal with protocol violations such as non-
confirmed for all patients.
compliance and cross-over between treatments, the analyses
were based on the groups as randomized, e.g., intention-to- The patients were randomized to either eccentric
treat analysis was used. Non-parametric statistics were used. exercises (N516), eccentric exercises and night
Post-treatment change across all times was assessed by splint (N515) or night splint only (N513). Data
Friedman’stest.Whenthistestwassignificant,post-treatment
were available for 33 (75%) patients after treatment
changeat6,12,26and52weekscomparedwithbaselinewas
(12 weeks), and for 35 (80%) patients at the 1-year
assessedbyWilcoxon’ssignedranktest.TheKruskal–Wallis
test was used when comparing three groups and the Mann– follow-up (Fig. 5).
WhitneyU-testwasusedwhencomparingtwogroups.Thew2
testwasusedforcomparisonofproportions.
Change over time within the groups
Table1. Self-reportedrecreationalactivities
All groups improved significantly across all times
Whichdescriptiondescribesyourrecreationalactivitiesthe (Po0.05). The eccentric group reported a signifi-
best?Pleasemarkonealternative.
cant pain reduction (27% compared with baseline,
6 Competitivesports:soccer,racquetsports,trackandfield, P50.007)alreadyat6weekswhichlastedfor1year
skiing,etc. (42%comparedwithbaseline,P50.001).Thegroup
5 Recreationalsports:jogging,skiing,racquetsports,etc.
treated with eccentric exercises and night splint
4 Golf,dancing,hiking,wateraerobics
3 Heavyyardwork,heavyhouseholdwork,walkingoneven reported less pain reduction (18% at 6 weeks,
ground P50.14; 22% at 12 weeks, P50.008; and 22% at
2 Lightyardwork,lighthouseholdwork,shopping 26 weeks, P50.08 compared with baseline). The
1 Minimalhouseholdwork,cardgames,sewing
grouptreatedwithnightsplintonlyreportedtheleast
0 Nohouseholdwork,TV,reading
pain reduction of the three groups (19% at 6 weeks,
289
Roos et al.
Table2. FootandAnkleOutcomeScore(FAOS)subscores(mean(cid:2)SD)ona0–100worst–bestscale
Pain Symptoms ADL Sport/rec QOL
Baseline
Exc 60(cid:2)19 61(cid:2)12 73(cid:2)20 42(cid:2)23 33(cid:2)17
Exc1splint 60(cid:2)13 60(cid:2)16 70(cid:2)18 43(cid:2)20 32(cid:2)16
Splint 61(cid:2)13 58(cid:2)13 69(cid:2)18 45(cid:2)20 48(cid:2)15
6weeks
Exc 77(cid:2)14 70(cid:2)19 85(cid:2)14 58(cid:2)24 46(cid:2)19
Exc1splint 71(cid:2)14 69(cid:2)15 81(cid:2)15 54(cid:2)19 40(cid:2)16
Splint 73(cid:2)16 72(cid:2)15 78(cid:2)20 59(cid:2)26 46(cid:2)17
12weeks
Exc 82(cid:2)18 79(cid:2)19 90(cid:2)14 74(cid:2)20 55(cid:2)28
Exc1splint 74(cid:2)16 71(cid:2)18 81(cid:2)18 58(cid:2)26 48(cid:2)23
Splint 69(cid:2)20 73(cid:2)15 79(cid:2)24 57(cid:2)26 48(cid:2)19
26weeks
Exc 84(cid:2)18 78(cid:2)22 88(cid:2)16 70(cid:2)28 61(cid:2)32
Exc1splint 74(cid:2)22 68(cid:2)20 80(cid:2)21 61(cid:2)31 46(cid:2)24
Splint 72(cid:2)29 74(cid:2)23 77(cid:2)26 61(cid:2)30 54(cid:2)30
52weeks
Exc 86(cid:2)17 83(cid:2)20 88(cid:2)16 74(cid:2)24 65(cid:2)27
Exc1splint 82(cid:2)19 77(cid:2)17 86(cid:2)21 65(cid:2)32 59(cid:2)21
Splint 83(cid:2)16 79(cid:2)17 87(cid:2)17 69(cid:2)26 62(cid:2)28
ADL5activitiesofdailyliving,Sport/rec5sportandrecreationfunction,QOL5footandankle-relatedqualityoflife,Exc5exercise.
Randomized
N=47
Not eligible Not eligible (too
(wrong young), n=1
diagnosis), n=2
Eccentric Eccentric+splint Splint group
group group
0 16 15 13 Total
weeks N=44
Excl (not Excl (lumbar Excl (want to try
possible to hernia), n=1 other treatment,
reach), n=1 Not returned not possible to
Not returned questionnaire, sleep with
questionnaire, n=3 splint), n=2
n=3
6 12 11 11 Total
weeks N=34
Excl (family Not returned Not returned
matter), n=1 questionnaire, questionnaire,
Not returned n=2 n=1
questionnaire,
n=3
12 11 12 10 Total
weeks N=33
Not returned Not returned
questionnaire, questionnaire,
n=3 n=1
26 11 13 11 Total
weeks N=35
Not returned Not returned Not returned
questionnaire, questionnaire, questionnaire,
n=2 n=2 n=1
52 13 12 10 Total
weeks N=35 Fig. 5. Flow chart ofpatients in the study.
P50.005;13%at12weeks,P50.14and17%at26 (Po0.001) compared with baseline (Fig. 6). Similar
weeks,P50.14comparedwithbaseline).From26to results were seen for improvement in the other
52 weeks, significant improvement occurred in both FAOS subscales covering other symptoms, function
groups treated with a night splint, and at 52 weeks, in daily life, sport and recreation function, and foot
all three groups reported pain reduction of 35–42% and ankle-related quality of life (Table 2).
290
Eccentric exercises for Achilles tendinopathy
95 declined over time and at 12 weeks only 50%
90 reported good compliance. The compliance with
e85 the night splint increased over the first weeks and
cor80 Achilles exc was good for most of the study period (Fig. 7). The
s
S 75 Achilles exc+splint numbers were too small in each group to calculate
AO70 Achilles splint the association between compliance and outcome.
F
65
60
55
e s s s s Side-effects
pr ek ek ek ek
Pain 6 we 2 we 6 we 2 we During the first week of treatment, 33% of patients
ain n 1 n 2 n 5 reported muscle soreness as a result of the eccentric
P Pai Pai Pai exercises. No differences were seen between the
Fig. 6. Mean ((cid:2)1 SE) FAOS pain score for the different eccentric group and the eccentric1splint group.
treatmentgroups atall different times. Four patients reported pressure-related problems
and two patients reported sleep disturbances be-
causeofthenightsplint.Duringweek3, onepatient
Comparison between groups
stopped using the night splint because of sleep
Nosignificantdifferenceswerefoundinpainbetween disturbances. The number of patients reporting
thethreegroupsatanypoint intime(P50.14–0.98). side-effects decreased over time and after week 6,
However, clinically significant differences of more no patient reported muscle soreness. One patient in
than 10 points in mean pain score in favor of the the eccentric group however continued to report
eccentric-only group compared with the splint-only calf muscle stiffness throughout the study and
group were present at 12 and 26 weeks (Table 2). two patients using night splints continued to have
When comparing the eccentric-only group and the problems with pressure-related pain now and then.
splint-onlygroup,thedifferenceinpainafter12weeks
of treatment was significant (82 vs. 69, P50.04).
Cross-over between treatments
At 12 months, 50% of the patients from the splint-
Physical activity level
onlygroupreportedhavingtriedothertreatmentsas
In the eccentric group, five of eight patients active compared with 15% from the groups performing
in sports prior to the onset of symptoms returned eccentric exercises (P50.04). One patient from the
to their pre-injury activity level after 12 weeks. In splintgroupreportedhavingtriedeccentricexercises
the eccentric1splint group, three of eight patients with no effect. One patient from the eccentric group
returned, and in the splint group one of 10 patients reported having tried night splint with no effect.
had returned to sports after 12 weeks. Other treatments included corticosteroids, acupunc-
ture, ultrasound, laser, massage, new shoes, topical
agents, orthotics, operation, stretching and con-
Difficulty during sporting activities centricexercises.Themedianreportedeffectofthese
treatments was poor on a five-point scale (no effect,
At baseline, more than 80% of the patients in all
poor,fair,good,verygoodeffect).Thirteenofthe33
treatment groups reported moderate-to-extreme
difficulty during sporting activities. At 12 weeks,
27% in the eccentric group compared with 58% in
100
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Compliance Fig.7. Percentageofpatientsreportinggoodcompliance(at
least 75% of recommendation) with the eccentric exercises
Compliancewasgood(atleast75%ofrecommenda- (unfilledbars)andtheuseofnightsplint(filledbars)during
tion)fortheeccentricexercisesforthefirstweeksbut thetreatment period.
291
Roos et al.
patients reported continuation of the allocated differences between the groups were present. We
treatment. found mean score differences of at least 10 points,
considered clinically relevant, in favor of the
eccentric group for pain and ADL function at 12
and 26 weeks, and for Sport and Recreation func-
Discussion
tion at 12 weeks. Only the difference in pain at 12
Our randomized controlledstudy,includingpatients weeks was statistically significant. Previous studies
from primary care and using validated outcomes, on eccentric exercise in Achilles tendinopathy have
confirmed previous studies showing that a home recruited a similar number of patients (Mafi et al.,
program of eccentric calf muscle exercises seem to 2001; Silbernagel et al., 2001), possibly indicating a
reduce pain and improve function because of general difficulty in recruiting patients with Achilles
Achilles tendinopathy. This study adds information tendinopathy. To increase power with a set num-
on that eccentric exercise is effective treatment of ber of patients, in theory, we could have chosen
Achilles tendinopathy also in patients seeking care a control treatment with less expected effect, used
within the primary-care system and that the im- more responsive outcome measures, or used only
provement seen after treatment lasts for 1 year. The two treatment groups. It was regarded impor-
patients in the present study represented a hetero- tant to choose a control treatment with the same
geneous group with regard to age, sex, activity level amount of attention for two reasons: to measure
and symptom duration. Previous studies have the effect of the exercise program as opposed
recruited patients referred to surgical treatment to attention, and to minimize the drop-out rate. At
(Alfredson et al., 1998; Mafi et al., 2001) and by the study center, night splints were increasing-
mailings to clinics and sports clubs (Silbernagel ly prescribed and thought useful for reduction of
et al., 2001) yielding patients more frequently pain and morning stiffness as a result of Achilles
involved in sports and with a longer symptom tendinopathy.
duration. Repeated studies yielding similar results The questionnaire used for assessment of patient-
in different populations strengthen the evidence of relevant outcomes in this study has been found
eccentricexercisesasagoodtreatmentformostsub- sensitive enough to detect treatment differences
jects with Achilles tendinopathy. betweensmallgroupsundergoingnon-surgicaltreat-
Pain reduction was seen already at 6 weeks as mentbecauseofkneecomplaints(Colkeretal.,2002;
compared with 12 weeks in previous studies (Al- Braham et al., 2003). Recently, the reliability and
fredson et al., 1998; Mafi et al., 2001; Silbernagel validity of a new outcome measure specific to
et al., 2001). The results lasted for 1 year. Other Achillestendinopathyhasbeenpublished(Robinson
evaluated parameters supporting eccentric exercises et al., 2001). This instrument was, however, not
being superior to treatment with a night splint available when our study started.
indicated that more patients in the eccentric groups Future studies should recognize the difficulty in
than splint-only group returned to sport after recruiting patients with chronic Achilles tendin-
treatment, and that fewer patients in the eccentric opathy and consider a multi-center design.
groups compared with the splint-only group re-
ported having tried other treatments during the
1-year follow-up.
Muscle soreness
Also the night splint group reported a significant,
yet smaller, initial reduction in pain. The effect was Thereasonforcombiningeccentricexerciseswiththe
highest at 6 weeks and less at 12 and 26 weeks (Fig. useofanightsplintinathirdgroupwastodecrease
6).Wesuggestinterpretingthisinitialpainreduction muscle soreness, a commonly reported side-effect of
as a placebo effect. Improvement was seen between eccentricexercises(Leeetal.,2002).Musclesoreness
6 and 12 months which could be interpreted as the was thought to be reduced by stretching. This belief
benign natural course of tendinopathy. The long- was however not supported by either the results of
term prognosis on subjective outcomes of Achilles our study or the recent literature. In our study, the
tendinopathy is favorable (Paavola et al., 2000). same number of patients in both groups perform-
ing eccentric exercise, with and without prolonged
stretching by the use of a night splint, reported
muscle soreness. In a recent systematic review of
Power of the study
the literature it was concluded that stretching be-
Wewere,despiteacloseto3-yearrecruitmentperiod fore or after exercising does not confer protection
involving more than 20primary-care physicians, not from muscle soreness (Herbert & Gabriel, 2002).
able to recruit the 60 patients needed to show To improve compliance with the treatment, it
statistical significance when clinically significant is important to inform the patients that muscle
292
Eccentric exercises for Achilles tendinopathy
soreness is to be expected when initiating the pathy, the following seven methodological sug-
program. However, by inclusion of the combined gestions were given (Tallon et al., 2001): (1) Ideally,
treatment group, we found that the use of a night studies should be randomized controlled trials. (2)
splint (prolonged stretching) seems to weaken Patient selection criteria should be clearly documen-
(modulate) the effect of eccentric exercises. This ted, giving the number of patients in the original
finding leads to speculations about the underlying study cohort, the number of patients who were
mechanisms behind the positive effects of eccentric lost to follow-up, and stating the reasons why it was
exercises on tendinopathy. not possible to follow them up. (3) The investiga-
tors responsible for outcome assessment should be
independent of the therapist and surgeon. Ideally,
Underlying mechanisms of eccentric exercise the outcome assessment should be in a written form
with minimal investigator assistance. (4) Ultra-
The mechanisms behind the positive effects of
sonography or magnetic resonance imaging (MRI)
eccentric exercises as treatment for tendinopathy
may be performed to assist in the diagnosis.
are largely unexplained. Previously, inflammation
The role of imaging in follow-up, however, is
was assumed to produce tendon pain. This assump-
dubious. (5) In assessing clinical outcome, there
tionis,however,contradictedbymany(Pudduetal.,
are two forms of benefit to the patient: relief of
1976; Astrom & Rausing, 1995; Movin et al., 1997).
pain and return to sporting activities. These points
More recently, mechanical and biochemical models
should possibly be incorporated into the patients’
have been suggested to explain tendon pain. Pain
records. (6) Researchers should use a reliable
is suggested to originate from either mechanical
and sensitive outcome measure. (7) The treatment
discontinuity of collagen fibers or biochemical irri-
period should be documented in detail, giving a
tation that results from damaged tendon tissue
full description of the protocol and the patient
activating nociceptors (Khan & Cook, 2000). In the
adherence and compliance to the protocol.
present study, eccentric exercises alone were asso-
Most of these suggestions, when applicable for
ciated with larger pain reduction than eccentric
non-operative interventions, were met in the present
exercises combined with prolonged stretching by a
study. The patients were randomized tothe different
nightsplint.Thisfindingsuggestsamodulatingeffect
treatment groups and monitored four times during
of prolonged stretching on the positive effects on
the 1-year follow-up. The number of dropouts and
pain of eccentric exercises. One parameter suggested
the reasons given were recorded (Fig. 5). We used a
to change in different directions when the muscle–
rigorously developed and tested patient-relevant
tendon complex is subjected to eccentric exercises as
outcome measure assessing symptoms, functional
opposed to stretching is stiffness of the muscle–
limitations and the result of these on patients’ qua-
tendon system. When moving a joint to a posi-
lity of life (Roos et al., 1998a,b, 1999, 2001). For
tion that lengthens the muscle–tendon complex, the
assessment of physical activity level, a reliable scale
tissues resist the change in length. The ratio of the
was used (Roos et al., 1999). To minimize investi-
change in resistance to the change in length refers to
gator bias, the questionnaire was mailed to the
thestiffnessofthesystem(McNeil-Alexander,1983).
patients and returned by mail (Roos, 2001). We
It is suggested that eccentric exercises improve
assessed compliance with the protocols by having
muscle–tendonstiffness(Porteretal.,2002)andthat
the patients record the number of daily repetitions
stretching reduces muscle–tendon stiffness (Kubo
of eccentric exercises and the use of the splint. The
et al., 2001; McNair et al., 2001; Cornwell et al.,
records were returned by mail after 6 and 12 weeks,
2002). Moreover, muscle–tendon stiffness decreases
respectively.
with age (Kubo et al., 2003) as the incidence of
We did not ensure the diagnosis by the use of
Achilles tendinopathy increases (Kvist, 1994). We
objective measures such as ultrasound or MRI.
suggest exploring the possibility that stiffness in the
Thus, it was possible that patients with clinical
muscle–tendon complex may play a part in Achilles
symptoms, but without structural signs of tendin-
tendinopathy and the positive effects seen of eccen-
opathy,wereincluded.Insteadweaimedatincluding
tric exercise.
only patients having pain and swelling 2–6cm from
the Achilles tendon insertion. Symptoms from the
Achilles tendon are frequently categorized into mid-
Suggested methodology for clinical studies on
tendon symptoms and symptoms from the insertion.
Achilles tendinopathy
Different etiologiesand prognoses forthesedifferent
Poor methodology is one suggested reason for the pain localizations have been suggested (Schepsis &
weakevidencefortreatmentoftendinopathy(Alme- Leach, 1987). To include only patients with mid-
kinders & Temple, 1998). In a critical review on the tendon Achilles tendinopathy, patients with pain
outcome of surgery for chronic Achilles tendino- from the Achilles tendon insertion, or pain from
293
Roos et al.
2–6cmproximaloftheAchillestendoninsertionand severity of the problems, should undergo an eccentric
pain from the insertion, were excluded. exercise program prior to consideration of other
treatments such as Achilles tendon surgery.
Key words: Foot and Ankle Outcome Score (FAOS),
Perspectives tendinopathy, tendinitis.
We conclude that eccentric exercises seem to im-
prove function and reduce pain because of Achilles
tendinopathy in patients recruited from primary care. Acknowledgements
The effects were apparent already after 6 weeks of
Supported by grants from the The Swedish National Center
treatmentandlastedfor1year.Ourresultsareinline
for Research in Sports, Zoega Foundation for Medical
with previous studies and strengthens the recommen-
Research, The Swedish Research Council and Lund Uni-
dation that patients, regardless of the duration or the versityHospitalandMedicalFaculty.
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