Rehabilitation Issues in Women With Anterior Cruciate ...users.clas.ufl.edu/msscha/whp_women_acl_review.pdf · hormonal influences, lower limb alignment, notch shape and di-mension,

Rehabilitation Issues in Women With AnteriorCruciate Ligament Deficiency

Giuliano Cerulli, M.D.,* Auro Caraffa, M.D.,* andFabrizio Ponteggia, M.D.†

SUMMARYAnterior cruciate ligament (ACL) noncontact injuries occur

more frequently in female than in male athletes. Many studiesinvestigated possible predisposing factors such as joint laxity,hormonal influences, lower limb alignment, notch shape and di-mension, ligament size, and neuromuscular control. To ourknowledge, there are no ACL rehabilitation protocols especiallystudied for women. Our approach is a time-based and criterion-based progressive rehabilitation protocol, with preoperative,early, and late postoperative phases. Preinjury, preoperative, andpostoperative biomechanical quantitative evaluations are used tomonitor rehabilitation. Sport-specific epidemiologic observationof noncontact ACL injury mechanism can help in identifyingmovements and situations that pose a risk to the ACL. These datacan be used to modify training and to prevent injuries and re-injuries. In our opinion, it is not necessary to have a gender-specific rehabilitation protocol, but it is necessary to have bettersport-specific neuromuscular conditioning, which should includeplyometrics, postural balance, and functional agility exercise pro-tocols.

Key Words: Anterior cruciate ligament, Female, Knee, Rehabili-tation

INTRODUCTION

The number of women participating in sports has in-creased markedly in recent years.1 Female athletes havea higher rate of anterior cruciate ligament (ACL) injury,

two to eight times greater than males.2 The possible predis-posing factors for ACL injuries in women have been de-scribed in several studies.3–6 These factors can be categorizedas gender-specific, sport-specific, and condition-specific.Gender-specific risk factors are generalized joint laxity, in-creased hormonal influences, different lower limb alignment(hip-knee-ankle, wider pelvis, increased genu valgum, in-creased Q angle), decreased intercondylar notch width, anddecreased ligament size. Sport-specific factors are equipment,field conditions, and type of sport (contact or noncontact). Inthe third group are training methods, experience, musclestrength, endurance, neuromuscular characteristics (slowermuscle reaction time and different muscle recruitment order),and technique and ability in executing specific athletic tasks.Some of the condition-specific factors are also gender-specific, and they can be improved. However, nearly always,they are unlikely to match male athletes’ characteristics.Given the high number of ACL lesions and reconstructions inwomen athletes, there is a need to improve preoperative andpostoperative rehabilitation protocols and to develop preven-tion strategies for both healthy and ACL-reconstructed ath-letes. To our knowledge, no gender-specific rehabilitationprotocols are reported in the literature. In this article, wereview the literature on major rehabilitation and preventionissues, and we present rehabilitation protocol guidelines, witha special emphasis on women athletes.

Preoperative Period

The interval between ACL injury and reconstructionmust be used by the patient to obtain reduction of joint swell-ing and pain, regain complete range of joint movement(ROM), recover normal gait, and maintain muscle tone andneuromuscular control. The time needed to reach these tar-gets is also a function of meniscal and other ligamentouslesions. Cryotherapy is a mainstay of treatment to reduce painand swelling, together with rest. If necessary, the patientcan take analgesics or non-steroidal anti-inflammatorydrugs (NSAIDs), and can use a light compression sleeve, as

From the *Department of Orthopedics and Traumatology, Silvestrini Hospital, Univer-

sity of Perugia, Italy; and the †School of Physical Medicine and Rehabilitation, Uni-

versity of Florence, Italy.

Address correspondence and reprint requests to: Giuliano Cerulli, M.D., Via Pontani 9,

06100 Perugia, Italy.

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needed. Active and passive joint motion, with knee flexion–extension and stretching of the hamstring to prevent flexioncontracture, should be started immediately to obtain or main-tain a range of motion equal to that of the contralateral knee.Isometric muscle contractions, especially straight leg raises(Fig. 1), should be performed in this phase. Electrical musclestimulation (EMS) of the quadriceps and hamstring shouldstart to slow progression of muscle atrophy. Crutches shouldbe used for allow partial weight-bearing, which should beincreased as tolerated. We do not allow weight-bearing inpatients with multiple ligamentous lesions; moreover, a braceis prescribed. We also use a brace if patients with ACL lesionexperience “giving-way” during activities of daily living.When the above targets are reached, a biomechanical evalu-ation is performed before surgery. If surgery is delayed, con-centric and eccentric exercises are prescribed, both in openkinetic chain (OKC) and closed kinetic chain (CKC), firstwithout (Fig. 2) and then with the use of resistance. Closedkinetic chain exercises and coactivation of quadriceps andgastrocnemius seems to be important for knee stability inpatients with ACL deficiency.7 If there are no giving-wayepisodes, the patient must also start simple proprioceptiveexercises with a wobble board. To decrease the time of reflexhamstring contraction latency (RHCL) and to improve dy-namic knee stability, a program of CKC exercises combinedwith exercises on wobble boards seems to be more effectivethan a traditional muscle strengthening alone.8 The difficultyof the exercises can be increased by performing them withclosed eyes.

Recently, a decision-making scheme was proposed forreturning patients to high-level activity with nonoperativetreatment after isolated ACL tears.9 The method is based onscreening administered through some tests. These includesingle, triple, cross-over, and timed hop tests, quadricepsfemoris maximum voluntary isometric strength tests, globalrating of knee function, the Knee Outcome Survey Activitiesof Daily Living scales, and the number of giving-way episodesfrom the time of the ACL lesion to the tests. Before the tests,patients must have no pain or swelling, and full ROM. The

long-term consequences on the knee joint of a high-levelactivity practice with an ACL deficiency have not been es-tablished until now. Recently, some investigations have beenperformed to study the stabilizing mechanism in joints withACL deficiency.10,11

Biomechanical EvaluationQuantitative evaluation of variables such as muscle

strength, muscle activity, range of motion, joint stability, pos-tural balance, and motion and gait patterns is important forthe rehabilitation of athletes with ACL deficiency. We usu-ally perform these tests on healthy athletes before and duringthe sport season, and we have therefore collected data ofnormal values for each athlete. These data are useful to iden-tify rehabilitation targets if an athlete sustains an injury. Thevalues obtained studying the healthy leg before the ACLlesion are more valid than data collected from the contralat-eral uninjured leg after the ACL lesion has occurred.

An ACL-deficient athlete is tested before surgery, andat the fourth and twelfth postoperative months. We evaluateconcentric and eccentric isokinetic strength. Stabilometry isperformed with a force platform. We test postural balancewith a K.A.T. 2000 unstable platform (Kinesthetic AbilityTrainer; Breg, Vista, CA). Electrical muscle activity, recruit-ment order, and reaction times are recorded with telemetricmultichannel surface electromyography. Gait analysis is stud-ied with force platforms. Motion analysis is performed withoptoelectronic systems of cameras linked to computer.FIG. 1. Straight leg raise.

FIG. 2. Squat: a closed kinetic chain exercise.

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Data from gait analysis, motion analysis, and electro-myography are recorded and then analyzed in a synchronizedway. The threshold to detect passive motion (TTDPM) toevaluate kinesthesia and the reproduction of passive position(RPP) to evaluate proprioception are static tests, performedwhile sitting, and thus not useful in monitoring rehabilitationof athletes who usually perform fast movements. Some pa-tients, despite good results in biomechanical and clinicalevaluation, are not subjectively satisfied after reconstruction.We believe that this is because of a lack of conditioning of theproprioceptive system, which cannot be tested properly andcompletely.

Physical Therapy ModalitiesCryotherapy (the therapeutic use of cold) is used to

reduce pain and joint swelling, immediately after the liga-ment lesion and in the postoperative phase. There are severalways to obtain tissue cooling, from simple bags filled withcrushed ice to continuous cold flow and compression devices.A swift reduction of pain12 and joint swelling13–15 is neces-sary, given their inhibitory role on quadriceps function. Weprescribe cryotherapy after each physiotherapy session for 20minutes, using an ice bag. If there is swelling, a cold com-pression unit is preferable. There is no agreement in literatureabout the effectiveness of cryotherapy. Some authors16–19

observed reduction in postoperative pain, length of hospitalstay, and analgesics consumption. Other studies showed noimprovement in hospital stay, knee girth, pain scale, analge-sics consumption, ROM, and drainage from the surgicalwound.20–22 Barber23 compared crushed ice with continuousflow cold therapy after ACL reconstruction. Continuous flowcryotherapy allows better knee flexion, lower analgesics con-sumption, and lower Visual Analog Scale (VAS) and Likertpain scores. Ohkoshi18 and Martin24 demonstrated loweringof intraarticular temperature using continuous flow cryo-therapy. We doubt the efficacy of ice bags applied over sur-gical dressing, because there is no evidence of reduction inskin temperature. However, they can be used for their placeboeffect. When using cryotherapy, it should be kept in mind thattoo tight a placement of the apparatus for too long may causenerve injury.25,26

There has been investigation of EMS of the quadricepsafter ACL reconstruction. Combined with isometric musclecontractions of the quadriceps, EMS improved rehabilitationsignificantly compared with isometric exercises alone.27 Af-ter identical surgical procedures and the same postoperativeregimens, the women’s quadriceps muscles atrophied twiceas much as the men’s.28 The authors also found that womenbenefited from electrical stimulation more than men. In men,there was no significant difference of atrophy, irrespective ofthe use of EMS. In women, there was highly significant re-duction of the degree of atrophy after EMS.

These findings could result from the number of testos-terone hormone receptors in female and male quadricepsmuscles,29 (Sartok T, thesis, Stockholm 1983), and could bedetermined by whether these receptors were occupied by tes-tosterone. The authors found that women have a much higher

content of unoccupied testosterone receptors than men. Be-cause testosterone initiates muscles anabolism after trauma orsurgery, and because men have more testosterone in theirblood than women, women atrophy more, and benefit morefrom EMS, than men. Lynn Snyder-Mackler30,31 found betterrecovery of quadriceps strength and of normal gait usinghigh-intensity EMS after ACL reconstruction.

In the light of these results, the early initiation of EMSafter ACL injury and after ACL reconstruction helps femaleathletes to maintain or regain muscle function more quickly.We introduce EMS from the third postoperative week, ifwound healing is complete. In the postoperative period, EMSshould not produce extension of the leg to avoid excessivestrain of the graft. Therefore, we recommend administeringEMS with the knee fully extended.

At present, portable EMS devices are popular amongathletes. It is difficult to compare the various EMS devicesand to establish the real effectiveness of this machine, be-cause of the many variables and automatic modulation of thestimulation. We explain to the athlete that EMS is only asmall part of the rehabilitation process, and that the devicecannot substitute for active exercises. More studies areneeded to investigate the efficacy of EMS. A randomized,double-blinded, controlled study published in 1999, matchingexercises alone with EMS combined with exercises, reportedno advantages in isometric and isokinetic muscle torque inthe EMS group.32

Postoperative TreatmentWe use a time-based and criterion-based rehabilitation

protocol. The targets of the postoperative rehabilitation are toregain full ROM with hyperextension equal to the contralat-eral knee, to regain muscle strength, and to retrain the pro-prioceptive system, returning the athlete to the level of pre-injury activity. Histologic studies on ACL graft showed thatligamentization process takes from 133 to 3 years.34 Clinicalstudies on the safety of accelerated rehabilitation35,36 dem-onstrate that surgical technique (positioning, tensioning, fixa-tion) and rehabilitation are more important than biologiccharacteristics of the graft. In the last few years, the rehabili-tation programs used for ACL reconstruction performed withbone patellar tendon bone (BPTB) or with doubled semiten-dinosus and gracilis (STG) tendon tend to be the same, be-cause of the improvement of fixation for STG.37–39

Researchers at the University of Vermont 40–48 studiedin vivo, with a strain gauge placed on the anteromedial bandof the ACL, the effects on the ligament of OKC and CKCexercises, stair climbing, and bicycling. They showed thesafety profile of a variety of exercises at the various stages ofthe ROM, with or without resistance. Before these studies,clinical and biomechanical investigations suggested that CKCexercises were safer and more effective than OKC in ACLrehabilitation.49–53 A combination of OKC and CKC exerciseis recommended.54 Another recent study comparing OKC andCKC reported no significant differences in functional im-provement (level walking, stair ascent, stair descent) mea-sured by gait analysis in the first 6 weeks after surgery.55 An

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investigation56 performed among the members of the Ameri-can Orthopedic Society for Sports Medicine showed widevariability in postoperative care (weight-bearing, braces, du-ration of physical therapy, return to activity). Guidelines andtargets of our rehabilitation program are as follows: bracelocked at 0° for 7 days; ROM 0° to 90° at the end of the firstpostoperative week (immediately after the removal of thebrace), without using continuous passive motion (CPM);ROM 0° to 120° at the end of the second postoperative week;full weight-bearing and full ROM between the third and thefourth postoperative week; initiation of swimming and ofexercising with resistance at the end of the fourth postopera-tive week; starting of generic proprioceptive exercises withwobble board at the end of the sixth postoperative week.

Proprioceptive Training

Eriksson asked in a recent editorial if it is possible totrain proprioception; moreover, he stated a need to come to aconsensus about definitions.57 Proprioception is the ability toknow the position of a part of the body in space. Assessmentof proprioception is performed with a modified isokineticdynamometer to investigate the joint position sense of thepatients, using the RPP test. The term proprioception is oftenused as synonymous with the proprioceptive system. This iscomposed of proprioception itself, kinesthesia, visual affer-ents, and vestibular afferents.58,59,60 This system provides thenecessary information for the control of posture and locomo-tion.61 Kinesthesia, the ability to detect joint motion and di-rection, can also be evaluated with a modified isokinetic dy-namometer to measure the threshold to detect passive motion(TTDPM) at slow angular speed. Reproduced passive posi-tioning and TTDPM are passive and static tests. They cannotreproduce the high-speed, dynamic, and sudden movementsthat cause ACL lesions in athletes. In addition, training ofproprioception and kinesthesia could perhaps improve sportspecific movements, but not prevent joint injuries or protectthe ACL graft. The test that could be employed for this end-point is the measure of the reflex hamstring contraction la-tency (RHCL), because contraction of the hamstring limitsanterior tibial displacement. The role of the hamstring is moreimportant in women as a compensatory mechanism to reachbetter functional joint stability.62 Hamstring and quadricepsreaction times appear to be the best variables to evaluatesubjective knee function.63 Recently, a Japanese study dem-onstrated that an ACL–hamstring reflex arc exists in hu-mans.64 Despite all the above tests, there is no valid methodto evaluate the proprioceptive system, and we can only test itscomponents (kinesthesia by TTDPM, proprioception byRPP).

Another useful test is stabilometry (by force platform)to evaluate static balance. Dynamic balance and coordinationtraining57 can be measured with an unstable platform. Noneof these tests is able to evaluate properly the whole of theproprioceptive system. The so-called generic proprioceptivetraining is usually performed with exercises on wobbleboards, increasing difficulty by lowering the stability of the

board, closing the eyes, or performing movements such assimulated steps upon the board (Fig. 3).

Proprioceptive training should probably be more prop-erly named balance training, coordination training, or neuro-muscular training. Proprioception should not be trained alone,but in concert with the whole system. After proprioceptivetraining, the results of the relevant quantitative evaluationsdid improve.65–68 There are only a few studies investigatingthe preventive role of this modality of training. Generic pro-prioceptive training programs are similar in the preoperativephase, after ACL reconstruction, and in the prevention set-ting. Because mechanoceptors are present in each joint struc-ture,69–78 including meniscus, posterior cruciate, medial col-lateral, and lateral collateral ligaments, when facing a patientwith an ACL-deficient knee, one should tackle all the com-ponents of the joint proprioceptive system. Proprioceptiveexercises may be even more important in women, consideringthe gender-specific risk factors for ACL injuries (joint laxity,decreased ligament size, neuromuscular control with slowermuscle reaction time, and different muscle recruitment or-der).

FIG. 3. Proprioceptive exercise with a board simulating a step toincrease difficulty.

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There is no agreement on the effectiveness of wobbleboard training. Caraffa reported a decreased ACL injury ratein a group of male soccer players trained with a balance boardtraining program.79 A Swedish study80 on female soccerplayers did not detect a protective effect of a balance boardtraining program. Other studies, of female handball players,81

female soccer players,82 and female basketball players,83 con-firmed the advantages of a prevention program. Another pre-ventive protocol, the Santa Monica or PEP (Prevent injury,Enhance Performance) Program,6,84 has been proposed. It con-sists of a 15-minute, five-part program (avoid vulnerable posi-tions, increase flexibility, increase strengthening, perform ply-ometrics, and increase proprioception through agility exer-cises), to be performed at the beginning of practice at leasttwice a week.

Hewett et al.85 conducted a prospective study to evalu-ate the effect of neuromuscular training based on plyometric-jump exercises on the incidence of knee injury in femaleathletes. The results showed that in the trained female, therewas a decreased incidence of knee injury. Heidt et al.86 de-scribed a reduction of lower leg injuries in female soccerplayers if preseason conditioning, including plyometric exer-cises, was performed.

Shelbourne and Davis87 reported that a program offunctional sports agility starting from the fifth postoperativeweek does not influence stability. Therefore, proprioceptionshould have the same relative weight of regaining full ROMand muscle strength in rehabilitation after sports injuries.

Sport-Specific Training

In our patients, we start generic proprioceptive trainingat the end of the sixth postoperative week after surgery, aftera clinical evaluation; 15 days later, they begin running in astraight line. Ten weeks after surgery, patients can start run-ning with change of direction, after a clinical evaluation. Atthe end of the third postoperative month, patients can startsport-specific training. Muscle training focuses on endurance(to delay muscle fatigue and consequent decline of proprio-ception)88–90 more than on pure strengthening exercises, to-gether with proprioceptive training to prevent re-injuries. Atthe end of the fourth postoperative month, before allowingthe athlete to return to play, clinical and biomechanical quan-titative evaluations are performed to check stability, ROM,muscle strength and activity, postural balance, motion, andgait pattern.

In this period, athletes also start to perform unexpectedmovements in the field, simulating a game. To identify whichof these movements are more frequent and dangerous forACL injury, epidemiologic gender-, sport- and level-specificsurveys are necessary, because there is little research thatidentifies the critical phases of each sport and the exactmechanisms of injury. Recent investigations to evaluate invivo ACL strain during soccer high risk situations for ACLinjury, such as rapid deceleration, have shown that during thismovement, there is a high level of ACL strain.91 Biomechan-ical analysis of the identified at-risk movement can evaluate

the degree of risk of given situations, thus allowing us to plansport-specific exercises in the late phases of rehabilitation.

CONCLUSIONSSport-specific and role-specific epidemiologic surveys

are necessary to ascertain the exact incidence and the dan-gerous movements and high-risk situations of ACL lesions insport, especially in sports that pose high risks for femaleathletes, such as basketball or volleyball, to develop individu-alized exercise programs. Gender-specific training or reha-bilitation programs are probably not necessary, but greaterattention to neuromuscular factors is needed to prevent injuryand to rehabilitate the athletes more effectively.

Biomechanical evaluation and clinical examination areimportant to monitor rehabilitation and to correlate researchdata with functional results. Quantitative measurements ofmuscle strength and endurance, ROM, joint stability, motionanalysis, gait analysis, electrical muscle activity, and posturalbalance are useful to check an athlete’s neuromuscular char-acteristics and to improve performance, allowing rational andindividualized sport-specific training and rehabilitation be-fore or after an ACL injury.

Training of the proprioceptive system, performed byselective muscle-strengthening, balance, and sport-specificfunctional agility exercises, helps to enhance body controland acquire better conditioning in healthy subjects, and toobtain better rehabilitation in ACL-reconstructed female ath-letes. Moreover, this type of training should allow the playerto react more quickly when there is an unexpected situation ofpoor balance, avoiding a possible joint injury (or re-injuryafter ACL reconstruction) or diminishing its consequences.These concepts have greater impact on women athletes, givenwomen’s anatomic and neuromuscular risk factors for ACLinjury.

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