PRACTICE GUIDELINES FOR ANTERIOR CRUCIATE LIGAMENT REHABILITATION: A CRITERION-BASED REHABILITATION PROGRESSION

Transcription

1 PRACTICE GUIDELINES FOR ANTERIOR CRUCIATE LIGAMENT REHABILITATION: A CRITERION-BASED REHABILITATION PROGRESSION TARA JO MANAL, MPT, and LYNN SNYDER-MACKLER, ScD, PT, SCS Knowledge related to the anterior cruciate ligament (ACL) and its role in the stabilization of the knee has increased exponentially since the 1980s. More precise and more anatomic surgical techniques have developed based on a growing body of literature on the anatomy and biomechanics of the anterior cruciate ligament. The rehabilitation arena has also risen to the challenge to provide state-of-the-art rehabilitation to complement advances in surgical stabilization. The understanding and integration of the abundance of literature on surgical reconstruction, graft biology, and behavior guides the design and progress of the rehabilitation program. Effective rehabilitation after anterior cruciate ligament reconstruction must balance the loading of tissues necessary to stimulate the recovery of the knee while at the same time avoiding stresses that compromise graft integrity. Historically, rehabilitation programs have been temporally based. A performance-based decision-making approach may prove to be more universally applicable and less confining. Achieving the critical clinical milestones, the basis for rehabilitation progression, ensures that all patients are adequately challenged while at the same time assuring that none are progressed too quickly. Combining contemporary surgical and rehabilitation techniques will maximize the patient's potential and ensure optimal patient function and satisfaction. KEY WORDS: anterior cruciate ligament, knee, rehabilitation, physical therapy The anterior cruciate ligament (ACL) plays an important role in the stabilization of the kneej,2 Disruption of this ligament can have devastating effects ranging from complaints of instability and buckling during high-level sports participation to reports of giving way while walking down the street or stepping off of a curb. Surgical techniques for ACL reconstruction have evolved over the past 15 years, and postoperative morbidity has diminished significantly. The improvements in surgical technique are a result of more detailed understanding of the anatomy and biomechanics of the ACL, the dynamic properties that the ligament displays during knee motion, and advancements in surgical approaches and technology. 3-6 The rehabilitation specialist must be cognizant of the evolution in surgical techniques and their impact on the patient's rehabilitation. There is abundant literature describing the surgical options for ACL reconstruction and the results of progressive rehabilitation programs. 7,8 Retrospective analysis of results of accelerated rehabilitation programs have been reported. 9-n These reports are confounded by the myriad of definitions of successful outcome after ACL reconstruction. The surgeon's primary concern is the passive anterior laxity of the tibiofemoral joint, which is a measure of the From the Department of Physical Therapy, University of Delaware, Newark, DE. Address reprint requests to Tara Jo Manal, MPT, Department of Physical Therapy, McKinley Laboratory, Room 309, University of Delaware, Newark, DE Copyright 1996 by W.B. Saunders Company /96/ /0 success of the graft fixation, integrity, and location, n The rehabilitation specialist is interested in postoperative functional morbidity: the impact of strength, gait, and balance on return to activity. 13 Successful outcome may also be related to pain, the ability to return to a preinjury activity, or a willingness to accept some limitation in activity. Functional recovery and patient satisfaction are results that are the benchmarks of a successful outcome) 4 The patient's response to surgical intervention is dependent on individual and genetic intrinsic factors as well as controllable and uncontrollable extrinsic factors. These factors include the following: preoperative fitness level of the patient, healing properties, status of the knee joint at the time of injury, the time from injury to surgery, and the presence of concomitant injury that occurred at the time of the ACL disruption The spectrum of patient presentations and responses is large. As a result of temporally based rehabilitation progressions, the focus has shifted to what we believe are more appropriate and more universal criteria-based guidelines. Achievement of clinical milestones is an indicator of readiness for rehabilitation progression. This decisionmaking tactic allows the therapist to adapt a treatment regimen to a young healthy athlete with an isolated ACL tear as well as to a middle-aged patient with persistent postoperative inflammation and range of motion (ROM) complications. The progression depends on the time necessary to reach the defined milestones that permit progress to the next rehabilitation stage. The criteria-based system protects a patient from premature advancement in the therapeutic setting simply because the time frame week Operative Techniques in Orthopaedics, Vol 6, No 3 (July), 1996: pp

2 is approaching. This approach also allows the patient with minimal postsurgical morbidity from being unjustifiably underchallenged. 1I Communication between the surgeon and the therapist is a critical component of successful rehabilitation after surgery. The exchange of information helps both professionals to maximize successful patient outcome. The rehabilitation specialist treating a patient after ACL reconstruction has previous assumptions about graft selection and fixation, tunnel placement, and graft tensioning, and the rehabilitation guidelines are predicated on these assumptions. The length and the type of graft influence the fixation available to the surgeon, and variations in fixation hardware impact the graft's loading properties. 2 The therapist's knowledge of the strengths of graft material and common fixation methods modify the decisions regarding the rehabilitation program. 2 -z2 Correct tunnel placement and graft tensioning allow restoration of full knee ROM and ultimately affect the in situ integrity of the graft. If full knee ROM is not achieved in the operating room, it is unlikely to be attained in rehabilitation, and forcing full knee ROM in this case may deliteriously affect the graft The surgeon's confidence in the achieved fixation and any postoperative limitations in ROM should be communicated to the therapist to allow for appropriate modification of the rehabilitation program. The rehabilitation program described in this report is predicated on several assumptions. We will address some of the more frequent complications and comorbidities that can affect rehabilitation. The focus however, will be on a spedfic population of patients who have an isolated ACL tear, no preoperative flexion contracture, meticulous reproducible surgical technique as outlined above, and have been referred to physical therapy no more than 5 days after surgery. Patients who do not meet these criteria can be treated with this progression; however, achievement of clinical milestones may be delayed. PREOPERATIVE TREATMENT One preoperative consultation is often all that is necessary to ensure that the clinical milestones are met. The patient should be able to volitionally activate the quadriceps. Neuromuscular electrical stimulation, or biofeedback, coupled with v01itional exercise can be used for a patient who has difficulty activating the quadriceps. The patient should have full knee extension equal to the contralateral knee. These two clinical milestones are required before surgery and are the only reason for more than one preoperative treatment visit in this time frame. Preexisting flexion contracture is associated with a much higher rate of postoperative morbidity and must be resolved before surgery.15i 16 Patients who are experiencing persistent and frequent episodes of giving way may be fitted for a brace that has an extension stop to protect the joint from further insult before surgery If a functional brace will be used postoperatively, it may be ordered during this visit. The patient may also be educated on the management of effusion. Ice, elevation, and avoidance of stressful activities will usually suffice, and patients rarely require supervised therapy to manage preoperative effusion. In cases in which health TABLE 1. ACL Rehabilitation Practice Guidelines Time Frame Clinical Milestones Activities Days 1-3 Passive ROM/active Wall slides ROM = 0-90 Patellar mobilization Quadriceps contraction Active superior glide Walking without crutches Week 2 Week 4 Week 6-8 Week 12 Full knee extension* Flexion >110 Use of cycle/stairclimber without difficulty Walking with full extension Use of stairs foot-over-foot KOS ADL >85% Flexion within 10 * Quad strength >50%* Normal gait pattern Full ROM* Quad strength >80%* Maintaining or gaining quadnceps strength Hop tests >85%* KOS sports questionnaire >70% Neuromuscular electrical stimulation Gait training Cycle/stairc]imber Step exercises Kinetron intervals Portal/incision mobilization Prone hangs if necessary Tibiofemoral mobilization with rotation Patellofemoral mobilization in flexion Progress exercise in intensity and duration Begin running progression Transfer to fitness facility Agility exercises Sports specific exercases NOTE. Discontinue treatments when goals are met. Recheck monthly until 6 months after surgery. *Compared with uninvolved, insurance plans impose strict limitations on the use of physical therapy or in cases in which proximity to a formal therapy location is limited, the preoperative session can also be used to inform patients of the clinical milestones expected in the first postoperative week. Under these circumstances, the therapist must be confident that the patient is capable of understanding the instructions and performing the initial postoperative plan independently. IMMEDIATE POSTOPERATIVE PHASE The immediate postoperative phase is the first week after surgery and includes approximately two to three visits (Table 1). Restoration of ROM, especially active knee extension, is the most critical component of early rehabilitation after ACL reconstruction. 15,16,3 The physical therapist and the surgeon should communicate with the patients and reinforce the goal that achieving full active knee extension is the highest priority milestone. Active assistive ROM can begin in the recovery room. The wall sliding exercise (Fig 1) and stationary cycling are among the first exercises we introduce. The complications resulting from a persistent flexion contracture can significantly hinder the rehabilitation process and may require a second surgical intervention. 31 In most cases, the second surgery is avoidable, and preventative measures should be aggressively performed if extension is not achieved and maintained. One helpful addition to the patient's home program is a passive stretch with a weighted bag pushing the knee into extension (Fig 2). Knee flexion range is also addressed in the first postoperative week when the patient is expected to achieve 90 of knee flexion and should be able to ride a stationary bicycle at minimal resistance for 5 to 10 minutes. The seat height is progressively lowered to emphasize knee flexion ROM. ACL REHAB GUIDELINES 191

3 Fig 1. Wall sliding exercise. (A) The uninvolved leg is used to help flex the involved knee, (B) The patient applies a force to help extend the involved knee, We encourage immediate weight bearing without crutches. Many patients use postoperative orthoses, some fixed in full extension and some hinged. The use of a brace should not preclude the patient from fully activating the quadriceps and achieving full active knee extension during ambulation. 32~3Unbraced gait training, under the supervision of a therapist, should begin on the first rehabilitation visit to ensure that the patient understands how to fully bear weight and fully extend the knee during the end of the stance phase of the gait. ACL-deficient patients ambulate with a characteristic flexed-knee gait pattern, which is a decreased knee flexion excursion during the stance phase to stabilize the knee. 34 This gait pattern can persist after surgery and complicate the restoration of proper tibiofemoral and patellofemoral mechanics) 4 Patellar mobility can also be compromised if abnormal knee kinematics continue after surgery.35 Patients who undergo reconstruction with a bone-patellar tendon-bone autograft may be particularly at risk because they may refrain from contracting the quadriceps to avoid pulling on the harvest site. Patellofemoral joint pain has been identified as one of the primary causes of postoperative morbidity after ACL reconstruction, especially in those who have had autologous bone-patellar tendon-bone procedures Early intervention with active and passive patellar gliding and scar mobilization after suture removal minimizes iatrogenic effects associated with graft harvesting. Patellar restrictions contribute to graft site complaints, ~and aggressive patellar mobilization should be initiated immediately. Patients should be taught to pull through the tightness with the use of their quadriceps to restore full gliding. Harvest-site pain or inflammation should be treated directly with therapeutic techniques such as patellar strapping, electrical stimulation, and transverse friction massage. Patellar mobility is an important component of this early postoperative phase for all patients after ACL reconstruction and should continue until normal active and passive patellar mobility is achieved. Persistent weakness of the quadriceps femoris muscle has been associated with long-lasting morbidity after ACL injury and reconstruction.32,33 Therefore, recovery of the quadriceps strength is a pivotal component of rehabilitation after ACL reconstruction. Postoperative effusion may result in some inhibition of the quadriceps very early in the rehabilitation process, but it should not persist. We focus on early active quadriceps exercise to minimize the effects of disuse. Quadriceps setting and straight-leg raising exercises are used early in the rehabilitation phase to enhance quadriceps activation. Quadriceps action is also encouraged during gait training; the patient is taught to contract the muscle with each step (even when an immobilizer or brace is used) to increase the volitional control of the muscle. Educating the patient on the importance of recovery of quadriceps strength and its impact on functional recovery is essential. EARLY POSTOPERATIVE PHASE Fig 2. Passive knee extension stretch using a weighted backpack. 192 The 2 to 4 weeks after surgery is considered the early postoperative phase and usually involves six to eight visits. The prone hang exercise is initiated if full extension is not achieved by 2 weeks after surgery. The patient is positioned prone and the pelvis is strapped to the table to prevent compensatory hip flexion during the procedure. Ten to 15 lbs of sandbag weights are attached to the patient's ankle for 15 minutes (or less if full range is achieved). The unsupported knee joint overhangs the table, allowing gravity-assisted stretching into full knee extension (Fig 3). This procedure is very uncomfortable, MANAL AND SNYDER-MACKLER

4 Fig 3. Prone hanging exercise for knee extension. not easily tolerated, and, in our opinion, as valuable as a motivational tool (to encourage diligent adherence to a passive home knee extension program) as it is therapeutic. In our clinic, approximately 10% of the patients require the use of prone hangs after uncomplicated ACL reconstruction, and rarely is it repeated more than three times. A greater percentage of problems with stiff knees can be expected in patients who had a flexion contracture preoperatively or those who are operated on acutely. Once full knee extension is restored, the treatment emphasis shifts to continued gains in knee flexion ROM. Initial supine wall slides or seated knee bends with the assistance of the uninvolved lower extremity are stopped to perform more aggressive full body weight-bearing knee flexion stretches as indicated. Knee flexion of 110 or greater is expected during the early postoperative phase. The recovery of quadriceps femoris muscle strength is the critical clinical milestone of the early and middle post0perative phases of rehabilitation because the knee ROM, patellar mobility, and inflammatory responses yield to intervention. Weight-bearing exercises are encouraged because of the stabilizing effect they provide to the tibiofemoral joinl These exercises are more commonly referred to as Closed chain exercises in the current rehabilitation literature. 39,4,47 These include but are not limited to the following: squats, leg press, step-ups, stair climber, toe raises, and Kinetron (Cybex Division of Lumex, Ronkokorea, NY). The introduction and progression of these exercises are dependent on rules of safety for both the patient and the healing graft: During the first 6 weeks, fixation strength is the biggest concern. The knee should not be exposed to forces in excess of the strength of the fixation. Common methods of soft tissue and bone-to-bone fixation are sufficient to withstand the progression described in this report for the early postoperative period.2,2~,41 Information about the biological status of the graft has largely been extrapolated from animal models and studies in which the knees were immobilized The model of graft incorporatipn is therefore incomplete, Graft strength has been reported to: d crease during the first 3 months and then to slowly increase in strength during the following months. It is unclear whether true revascularization occurs or whether a bldod: supply is reestablished via a synovial envelope that surr0un~ts the graft. 4s In any case, it is clear that fhe graft is the strongest on the day it is implanted and probably never regains that strength. Allograft tissue appearst 0 have si0wer rates of incorporation than autograa tissue, 46 Research into the strains produced in the ACL and graft during various exercises has given some insight into the forces to which the graft is exposed. 3,s The underlying thread in all these reports is the notion that the absence of strain is the therapeutic goal. rn every other instance of encouraging healing, tissues respond appropriate to loading. The critical issue related to exercise progression after ACL reconstruction is not the removal of all strain from the graft but the determination of the optimal loading of the graft to encourage healing without stretching or rupturing the graft. Taken to its logical conclusion, absence of strain should result in stress shielding and graft failure. An integrative approach advocates modulated activities that present appropriate graft stresses and facilitate muscular recovery. 47 Our response to the contention that the graft is the weakest at the 12-week time period is that only good dynamic stability will protect the graft at this time. We therefore use the 8 to 12-week period as a target for full recovery of the stabilizing knee musculature. In a randomized, controlled, clinical trial, we have previously shown that closed chain kinetic exercises alone are not sufficient to restore quadriceps strength after ACL reconstruction. 48 The quadriceps strength deficits were clinically and functionally detectable in gait parameters. 34 High-intensity electrical stimulation has been shown to ameliorate early and substantive quadriceps strength loss and is a cornerstone of our postoperative rehabilitation program. 49 The stimulation protocol is begun as soon as the superior arthroscopy portal sutures are removed. The patient is positioned in a dynamometer with the knee flexed between 45 and ,5,51 The patient performs a maximum voluntary isometric contraction (MVIC), and the results are recorded. The electrodes are placed proximally over the lateral quadriceps and distally over the vastus medialis oblique. The quadr[ceps are stimulated isometrically with a 2,500-Hz alternating current modulated at 75 bursts per second with a 2-second ramp time, 10 seconds on and 50 seconds off for 10 to 15 contractions. The stimulation intensity is set to a minimum force level of 50% of the MVIC. The contractions are isometric, and entirely electrically elicited (not superimposed on a volitional contraction). The ACL rupture and resultant surgical intervention affect the proprioceptive and kinesthetic sense in the patient's knee. 14,52 Although surgical stabilization and return of muscle strength and knee joint ROM are essential to recover3# they are not sufficient to restore proprioceptive ability. Dynamic weight-bearing exercises provide stress to this integrative system in a very controlled and limited manner. 39 The introduction of more challenging balance and control exercises is therefore essential. Activities involve the use of the balance board, the mini trampoline, and rubber bands or tubing, and their use is limited only by the creativity of the supervising therapist MIDDLE POSTOPERATIVE PERIOD The 5 to 8 weeks after surgery is considered the middle postoperative period and usually involves four to eight visits. During this phase of the rehabilitation, the focus is on activity progression and the patient is transferred to a local fitness facility. The exercises have been progressed to continue to challenge the patient. Full knee extension has ACL REHAB GUIDELINES 193

5 been achieved, full patellar mobility has been restored, scar management has been addressed, the patient has been tested to determine if the clinical milestones have been met, and the patient no longer requires supervised therapy sessions. The electrical stimulation is continued until the patient can achieve an involved quadriceps MVIC, which is 80% or greater than that of the uninvolved knee. This milestone is generally achieved between the sixth and eighth postoperative week. Knee flexion ROM should be 90% or greater than that of the uninvolved knee. If a functional brace is requested by the referring surgeon, it is ordered at this time. If there are no complications and these milestones are met, the patient is transferred to an independent program at a local fitness center. The patient begins treadmill running and continues to progress the exercises previously performed in the clinic. 53 LATE ACL POSTOPERATIVE PHASE The 8 to 12 weeks after surgery is the late ACL postoperative phase. The emphasis during this phase of rehabilitation is the continued progression of activity level and maintenance of quadriceps recovery. Continued emphasis is placed on proprioception and cutting activities are avoided. Sport-specific activities in straight planes are introduced and progressed as the patient recovers. For the patient who progresses without difficulty, biweekly or monthly follow-ups are used to update or modify the treatment plan. The tensile strength of the graft is lowest (50%) at the 3-month postoperative period and must play a role in treatment planning for this time period. If a patient's quadriceps recovery is not sufficient, there are proprioceptive deficits, or they lack confidence in the function of the knee, these issues need to be addressed to avoid injury. The patient is reexamined at 8 weeks and again at 12 weeks. The failure to maintain quadriceps strength may necessitate resumption of supervised therapy. The patient also performs a series of hop tests 54 at the 12-week testing session to ensure that both the ability and the willingness to use the limb in an explosive manner are returning. 5~,56 A score of 85% or greater than that of the uninvolved is the clinical milestone for this time period. END OF ACL REHABILITATION PHASE The 3 to 6 months after surgery is considered the end of the ACL rehabilitation phase. The patient accelerates the sportspecific activities and continues an independent exercise program during this phase. The patient continues the running progression from the treadmill to the track, to flat road/field running, and finally to hill running. Running advancement is dependent on the return of balance, agility, and the ability to run 2 miles at each level without pain or swelling. 53,55,56 The full progression can take as long as 3 months. The MVIC and hop testing is repeated at the 6-month time period, and scores of 90% or greater are expected on both scales. These criteria are often achieved at the 3-month mark, but the patients are retested to insure that no deficits have recurred. Patients are most concerned about when they can return to their sport. Even if the patient's muscle strength is restored and balance and agility is recovering, the return to sport involves uncontrolled factors. Our guidelines for return to play are the culmination of progressive sportspecific return-to-independence skill drills, practice participation, and, finally, play. These guidelines are applied to patients who uneventfully achieve all clinical milestones and have no postoperative complications. We expect patients to return to full playing status for level 3 sports (running) at 3 to 4 months, level 2 sports at 6 to 9 months (depending on position played), and level 1 sports at 9 to 12 months. Patients usually begin practice activities 2 to 3 months before resuming full competitive activity. CONCURRENT KNEE JOINT INJURIES The effect of concurrent knee pathologies in the ACL reconstructed knee is as varied as the potential pathology list. The impact that concomitant injury and surgical intervention have on the progression of the ACL rehabilitation is dependent on the involved structure and timing of injury or surgery. The rehabilitation specialist's understanding of each coexisting pathology comprises the tools needed for modification of the postoperative rehabilitation plan. An accurate identification of the most limiting factor in need of protection is the critical decision-making component for any multiple injury situation. MENISCAL PATHOLOGY Partial meniscectomy requires no modification in the rehabilitation processj Concurrent meniscal repair however, may require modification of the rehabilitation progression. Weight-bearing flexion past 45 is avoided for the first 4 weeks. This does not preclude weight bearing in full knee extension, which helps to prevent loss of knee extension ROM and encourages quadriceps activation. Exercises that do not stress the repair but do allow for quadriceps recruitment should be substituted for closed chain exercises during the first 2 weeks. Non-weight-bearing exercises such as seated Kinetron and multiangle quadriceps isometrics are excellent substitutes. CHONDRAL DAMAGE Treatment of an ACL-reconstructed knee with chondral damage to a weight-bearing surface is similar to that used after meniscal repair. We cannot restrict weight bearing long enough to allow full healing of the articular cartilage defect after drilling or microfracture without compromising the ACL rehabilitation. We do however, restrict weight bearing for the first 3 to 4 weeks and refrain from weight-bearing exercise. The use of a brace that unloads the side of the chondral defect can be helpful in allowing earlier protected functional activities. 57 MEDIAL COLLATERAL LIGAMENT INJURY The medial collateral ligament (MCL) is rarely surgically repaired. 18,58 When an MCL injury occurs at the time of an ACL rupture, the stabilization of the knee provided by the ACL reconstruction usually provides an adequate environment for the healing of even a grade 3 MCL sprain. During 194 MANAL AND SNYDER-MACKLER

6 the rehabilitation process, motion should be restricted to the sagittal plane to avoid any inadvertent stress on the healing MCL. We also encourage the patient to position the tibia in internal rotation while performing exercises during the early postoperative period. If the sprain is severe or the patient has pain, a brace can be used during exercise and periods of activity with no significant impact on the treatment progression. ACL AND POSTERIOR CRUCIATE LIGAMENT RECONSTRUCTION The rehabilitation of patients after concurrent ACL and posterior cruciate ligament injury generally follow posterior cruciate ligament rehabilitation guidelines. 19,59,6 A full review of rehabilitation for this population is beyond the scope of this report; however, mitigation of the patient's expectations and discharge activity level may assist greatly in the patient's perceived outcome and ultimate knee function satisfaction. ACL RECONSTRUCTION AND PATELLOFEMORAL JOINT PATHOLOGY Anterior knee pain can be a persistent problem after the harvest of the central third of the patellar tendon for use as an ACL graft Anterior knee pain can also occur as a result of the perforation of the infrapatellar fat pad by the arthroscope and partial resection of the fat pad that is necessary for visualization during ACL reconstruction. The quadriceps weakness, which occurs after ACL injury, compounds this problem. Treatment of the patellofemoral joint may be necessary to allow for effective strengthening of the quadriceps. Treatment may include patellar strapping, modalities, or biofeedback to assist in quadriceps muscle recruitment. Care should be taken to address symptoms as they occur. The full activation of the quadriceps remains the focus for complete return of a normal gait and function after ACL reconstruction. Patients must be encouraged to recruit the quadriceps early; adhere to stringent harvest, incision, and portal site mobility; and maximize patellar mobility to avoid any pain-inhibited volitional quadriceps strength deficits. ACCESS TO PHYSICAL THERAPY An additional extrinsic factor that impacts the rehabilitation process is health insurance plans that severly restrict access to physical therapy. Some health insurance plans put time limits on care (eg, 60 days from the first visit), and some restrict the number of physical therapy visits. In the first case, the challenge is to make the timing fit the rehabilitation. In the second case, the challenge is to strategically allot visits to ensure the achievement of the critical clinical milestones. The distribution of available treatments will vary depending on individual patient needs and insurance carrier restrictions. The intervention we have outlined is based on an 18 to 20-visit program. This involves 2 to 3 visits per week for the first 4 to 6 weeks and allows for monthly follow-ups and 3- and 6-month testing sessions. Failure to attain clinical milestones may necessitate a variation from this typical disbursement pattern. For example, a failure to achieve full knee extension by week 2 will necessitate an increase in visits per week until full extension is achieved and the overall distribution of the treatments must be altered. In certain cases, persistent range of motion or strength deficits may require more intensive rehabilitation to achieve the clinical milestones. Careful attention must be paid to the use of rehabilitation resources. The full return to function is dependent not only on early intervention but also appropriate advancements even in the late postoperative phases. If the use of available rehabilitation resources is mishandled early, the potential effects may be a less functional and less satisfied patient. 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