The Journal of Arthroplasty Vol. 13 No. 4 1998              Preoperative Physical Therapy in Primary                      ...
Preoperative PTin PrimaryTKA    •   Rodgers et al.   415training in patients with knee osteoarthritis [ 17,18].   The HSS ...
416    The Journal of Arthroplasty Vol. 13 No. 4 June 1998Fig. 1. Mid-thigh "single slice" computed tomography scan analys...
Preoperative PTin PrimaryTKA                               •    Rodgers et al.              417ioo                        ...
418       The Journal of ArthroplastyVol. 13 No. 4 June 1998                          60 deg./se¢.                        ...
Preoperative PTin PrimaryTKA            •   Rodgers et al.   419                                              Table 3. Com...
420      The Journal of Arthroplasty Vol. 13 No. 4 June-1998     Few investigators h a v e studied the effect of pre-     ...
Preoperative PTin PrimaryTKA        •   Rodgers et al.   42115. Fisher NM, Pendergrast DR, Calkins E: Muscle reha-        ...
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Preoperative physical therapy in primary total knee arthroplasty


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Preoperative physical therapy in primary total knee arthroplasty

  1. 1. The Journal of Arthroplasty Vol. 13 No. 4 1998 Preoperative Physical Therapy in Primary Total Knee Arthroplasty J e f f r e y A. R o d g e r s , M D , * K e v i n L. G a r v i n , M D , * C r a i g W. W a l k e r , M D , t D e e M o r f o r d , RN, M P A , * J o s h U r b a n , M D , * a n d J o e B e d a r d , B S t Abstract: In order to evaluate the efficacy of preoperative physical therapy for patients undergoing elective primary total knee arthroplasty, l0 patients completed 6 weeks of physical therapy before surgery (PT group). Ten patients served as controls (C group). Subjects were tested at baseline (PT only), before surgery, 6 weeks after surgery, and 3 months after surgery using the Hospital for Special Surgery knee rating scale, range of motion, thigh circumference, walking speed, Cybex II isokinetic knee flexion, and extension testing, and computed tomography scanning for cross- sectional muscle area. Hospital stay and need for physical therapy after inpatient rehabilitation were also compared. Physical therapy produced modest gains in isokinetic flexion strength in these severely arthritic knees but no difference in extension strength. The decrease in isokinetic strength after surgery was not affected by preoperative physical therapy. Muscle area did not decrease significantly for the PT group, but it did decrease for the C group after surgery. While postoperative strength differences could not be demonstrated, preoperative physical therapy preserved thigh muscle area after surgery. The clinical significance of this finding is uncertain. Consequently, this study failed to support the routine use of preoperative physical therapy in knee replacement surgery. Key words: preoperative physical therapy, range of motion, osteoarthritis.Despite advancements and research in surgical tech- strength loss beyond the age of 50 years [4]. Innique, prostheses, and modalities of rehabilitation, addition, a negative nitrogen balance develops fol-scant attention is paid to preoperative physical lowing major orthopaedic procedures [5]. Consider-preparation of the patient for w h o m total knee ing this list of compounding factors, patients under-arthroplasty (TKA) has been prescribed. Weakness going total knee replacement begin the long journeyof both the quadriceps and hamstrings, in contrast to recovery substantially the contralateral limb, is commonly observed in While the large body of knowledge evaluatingpatients with osteoarthritis of the knee [1,2]. After postoperative physical therapy, including continuousTKA, significant further atrophy of the quadriceps passive m ot i on (CPM) and electrical stimula-has been shown histologically [3]. An age-related tion [6-12] continues to grow, the role of preopera-decline in overall muscular strength also begins in tive physical therapy in TKA has not been estab-adulthood with a significant increase in the rate of lished, and research is extremely limited as to its efficacy [2,13]. The ability of the elderly to respond to heavy resistance strength training, however, has From the Departments of *Orthopaedic Surgery and y-Radiology,University of Nebraska Medical Center, Omaha, Nebraska. been clearly demonstrated [14-16]. While it may Reprint requests: Jeffrey A. Rodgers, MD, Des Moines Ortho- seem that patients with severe osteoarthritis may bepaedic Surgeons, P.C., 6001 Westown Parkway, West Des Moines, unable to complete a successful preoperative physi-IA 50266. Copyright © 1998 by Churchill Livingstone® cal therapy program, well-designed studies have 0883 -5403/1304-000853.00/0 shown both feasibility and effectiveness of strength 414
  2. 2. Preoperative PTin PrimaryTKA • Rodgers et al. 415training in patients with knee osteoarthritis [ 17,18]. The HSS knee score was performed by the seniorThe purpose of this controlled investigation was to investigator or his resident staff, while the remain-evaluate prospectively the effects of preoperative der of the testing was performed by a certifiedphysical therapy on short-term outcome variables physical therapist. The duration of hospitalization,following primary TKA. need for posthospitalization physical therapy, and complication rates were also compared. Materials and Methods Muscle AreaStudy Population All patients also were examined with a "single- From December 1992 to August 1995, patients slice" CT examination of both thighs for muscle areascheduled by the senior author of this report for using a previously described technique [16] atunilateral primary TKA for osteoarthritis were re- baseline (PT only), before surgery and at 6 weekscruited to participate in the study. Patients with a after surgery (Fig. 1). The cross section of interesthistory of uncontrolled hypertension, cerebral aneu- was established using the midpoint between therysm, unstable angina, or any other contraindica- center of the femoral head and the medial femoraltion to high-intensity physical exertion or testing condyle. The absolute measurement from the cen-were excluded. According to the Investigational ter of the femoral head to the midpoint of theReview Board-approved protocol, patients were femoral shaft was used for subsequent scans. Theassigned to the control (C) group or the physical images were analyzed using MTRACE (University oftherapy group (PT) based on their geographic avail- Iowa, 1992) on a SUN image-processing station.ability. Those from the focal metropolitan area were Gray scale levels ->i corresponded to muscle andinvited to participate in the PT group, while those those ~<0 corresponded to fat. The bone was ex-living too far to attend the physical therapy sessions cluded using the region of interest function. Thewere invited to participate in the C group. Origi- number of pixels for each group were then countednally, 11 patients were enrolled in the C group; one and converted to square centimeters. Using thiswithdrew from the protocol for personal reasons, technique, intramuscular fat was excluded.which left a group of I0 to complete the study.Group C comprised five m en and five w o m e n withan average age of 65 years (range, 50-83). The Interventionoriginal PT group enrolled 12 patients, two of these The PT group completed 6 weeks of preoperativediscontinued the protocol: one patients operation physical therapy three times per week under thewas cancelled because of occult coronary artery direction of a certified physical therapist. Eachdisease and the other was unable to perform the patients program was individualized according tophysical testing because of fibromyalgia. The remain- their baseline physical capacity and reevaluated anding 10 patients who completed the preoperative advanced accordingly after 3 weeks. Exercises in-physical therapy protocol included four m en and six cluded stretching and warm-up, heel-slides, isomet-women, with an average age of 70 years (range, ric quadricep sets, straight leg raises, short-arc quad-63-78). There was no statistical difference in the age ricep sets, standing squats, step-ups, and bicycling.or sex distribution of the two groups. One of the Both groups received preoperative physical therapypatients in the control group had undergone contra- instruction in the usual postoperative exercise pro-lateral TKA 1 year before the study, otherwise all tocol.other patients had native knees. All patients were reconstructed using the same posterior-stabilized cemented total knee implant (Insall-Burstein II, Zimmer, Warsaw, IN). They re-Physical and Functional Testing ceived the same postoperative physical therapy Before surgery subjects were tested at baseline including ankle pumps, quadricep sets, straight leg(PT only), and then at 6 weeks and 3 months after raises, short-arc quadricep sets, heel-slides, assistedsurgery. Testing and measurement included Hospi- flexion, calf-stretching, hamstring-stretching, ham-tal for Special Surgery Knee Rating Scale (HSS Knee string sets, hip abduction, and hip adduction exer-Score) [19], range of motion, Cybex II (Lumex Inc., cise. Patients started gait-training (weight-bearingRonkonkoma, NY) isokinetic knee flexion and exten- as tolerated) beginning on the first postoperativesion testing (3 practice trials followed by 3 testing day. Depending on the patients progress and livingtrials at 60°/s and 180°/s), walking speed (10 m situation, patients were either discharged to homenormal and tandem gait), and thigh circumference. with instructions for a home physical therapy pro-
  3. 3. 416 The Journal of Arthroplasty Vol. 13 No. 4 June 1998Fig. 1. Mid-thigh "single slice" computed tomography scan analysis. (A) Representative CT scan with region of interestfunction activated. (B) Histogram of Gray scale distribution: -->1represents muscle and <--0represents fat.gram or transferred to a geriatric rehabilitation Resultscenter for supervised physical and occupationaltherapy. At the discretion of the senior author,outpatient physical t h e r a p y was prescribed postop- Physical and Functional Testingeratively as necessary, regardless of their study The groups did not differ significantly with respect togroup designation. extension and flexion range of motion over time, although a trend toward decreased motion was demon-Statistical Analysis strated for both groups at the 6-week evaluation Statistical analysis of the data included Repeated (Table 1). The thigh circumference and 10-m walkMeasure Analysis of Variance to compare the trends times also did not differ significantly over time for eitherb e t w e e n the groups and t test: Paired Two-Sample group. Hospital for Special Surgery knee rating scoresfor Means for comparison of differences within each improved for both groups at the 3-month follow-upgroup. with no difference in degree of improvement (Fig 2). Table 1. Anthropometric and Physical Testing Data R a n g e of M o t i o n Thigh Circumference W a l k Time Extension Flexion HSS Score Involved Uninvolved 10 m 10 mT Mean Range Mean Range (cm) (cm) (s) (s) Score RangeControl Preop 8 0-25 i13 77-i44 52 52 l0 35 54 40-67 6 weeks 9 0-28 104 84-i26 52 51 13 34 3months 6 0-20 113 80-117 5i 50 9 32 85 68-97PT Baseline 4 0-10 112 99-130 52 53 9 35 60 44-79 Preop 7 0-25 112 85-128 53 53 10 33 6 weeks 5 2-15 i01 85-125 51 51 12 36 3months 4 0-10 109 95-i20 52 51 10 26 87 79-95 HSS, Hospital for Special Surgery; Preop, preoperative; PT, physical test.
  4. 4. Preoperative PTin PrimaryTKA • Rodgers et al. 417ioo 60 deg./sec. • Control 80 M PT 100 60 80 60 40 40 20 20 0 0 base 3 mo Flexion Extension F i g . 2. H o s p i t a l f o r S p e c i a l S u r g e r y k n e e r a t i n g s c o r e s . F i g . 3. P r e o p e r a t i v e p e a k f l e x i o n a n d e x t e n s i o n t o r q u e : c o n t r o l g r o u p (60°/s).Isokinetic Testing Data decreased 4 0 % (P = .007) in flexion and 30% Table 2 s u m m a r i z e s the isokinetic p e a k torque (P = .02) in extension. The 3 - m o n t h testing re~data for b o t h groups. At p r e o p e r a t i v e (C) and vealed recovery to baseline strength for b o t h groupsbaseline (PT) evaluation, the involved k n e e was at 60°Is and 180°/s. Values i m p r o v e d for the PTsignificantly w e a k e r for b o t h groups in flexion a n d group f r o m 6 w e e k s to 3 m o n t h s 9 ft lb (36%) inextension at 60°/s (Figs 3, 4) a n d for flexion at flexion (P = .02) and 13 ft. lb (33%) in extension180°/s for the C group only. Significant strength (P = .002). The C group failed to d e m o n s t r a t e ai m p r o v e m e n t w i t h training was d e m o n s t r a t e d for statistically significant i m p r o v e m e n t during this in-the PT group w i t h a 5 ft lb increase in flexion terval. Overall, repeated m e a s u r e s analysis of vari-strength at 60°Is (17%, P = .01) f r o m baseline to ance revealed no significant difference b e t w e e n thepreoperative. Extension strength i m p r o v e d a m e a n groups over time.of 2 ft lb but was not significant (Figs 5, 6). Both groups d e m o n s t r a t e d decreased p e a k - t o r q u e Muscle Areaat 60°/s in the involved k n e e at the 6 - w e e k follow-up. The C group decreased 2 8 % (P = .06) in flexion The cross-sectional muscle area of the thigh failedand 30% (P = .05) in extension, while the PT group to change significantly for the PT group f r o m base- Table 2. C y b e x I s o k i n e t i c Testing P e a k Torque (ft-lb) Flexion Extension 60 d e g / s 180 d e g / s 60 d e g / s 180 d e g / s Uninv Involved Uninv Involved Uninv Involved Uninv InvolvedControl Pre-op 42a 32b 32c 26d 8in 57o 46p 42q 6 week 43 25e 34 22 79 44r 48 33 3 month 42 33f 29 28 85 56s 50 38PT Baseline 36g 30h 26i 21j 70t 51u 45v 35x Pre-op 43 35k 29 25 73 53y 46 37 6 week 38 251 30 13 71 40z 46 28 3 month 39 34m 30 24 67 53aa 43 37P vaIues a vs. b 0.03 n vs. o 0.02 paired N e s t c vs. d 0.02 p vs. q ns b vs. e 0.06 o vs. r 0.05 e vs. f ns r VS. S ns g vs. h 0.05 t vs. u 0.03 i vs. j ns v vs. x ns h vs. k 0.01 u vs. y ns k vs. 1 0.007 y vs. z 0.02 I vs. in 0.02 z vs. aa 0.002
  5. 5. 418 The Journal of ArthroplastyVol. 13 No. 4 June 1998 60 deg./se¢. 60 deg./sec.ft.ibs. ft-lbs80 60 Control60 -ll- 50 PT .,¢..40 4520 40 0 3 5 ~ Flexion Extension "base pre-op 6wk* 3moFig. 4. Baseline peak flexion and extension torque: physi- Fig. 6. Extension peak torque over therapy group (60°/s).line to preoperative (Table 3) for either the involved I0 in the C group and 7 of 10 in the PT group). Noor u n i n v o l v e d extremity. Involved thigh muscle patient in either group developed clinically evident deep venous thrombosis nor did t h e y require fobarea decreased from a m e a n of 105.3 cm 2 to 94.0cm 2 (not significant) for the PT group, while the low-up knee manipulation for p o o r range of mo- tion. In a follow-up "exit interview," 9 of l0 of thearea decreased from 1 I2.5 cm 2 to 90.1 cm 2 (P : .04) patients in the PT group said they felt the preopera-for the C group (Fig. 7). The u n i n v o l v e d extremity tive physical t h e r a p y helped t h e m prepare for sur-did not change significantly 6 weeks after surgery gery, and they would do it again if they were to havefor either group. Again, repeated measures analysis the opposite knee reconstructed.of variance failed to demonstrate a difference be-t w e e n groups. DiscussionHospitalization and Physical Therapy Functionally, preoperative physical t h e r a p y doesUtilization not appear to have a significant effect on range of Acute hospital stays averaged 5 days (range, 3-9 m o t i o n or maximal walking speed. Likewise, theredays) for the C group and 6 days (range, 3-12 days) was no difference in the degree of i m p r o v e m e n t forfor the PT group. Rehabilitation unit stays were the HSS knee scores. This i n s t r u m e n t relies onrequired for four patients in the control group estimations of pain and subjective measures of(mean stay, 6 days) and for six patients in the PT function, strength, and stability [19]. Subtle differ-group (mean stay, 4 days). Overall hospitalization ences w o u l d be difficult to detect using this mea-(acute and rehabilitation) did not differ b e t w e e n sure, especially considering the t r e m e n d o u s impactgroups and averaged 8 days for the PT group and 7 of surgery alone.days for the C group. Isokinetic strength testing is a reproducible and The n e e d for additional o u t p a t i e n t physical c o n v e n i e n t m e a n s of assessment of strength int h e r a p y was also not different b e t w e e n groups (6 of m a n y pathologic conditions {20]. Peak torque is the variable that is traditionally assessed in isokinetic studies and has p r o v e n most reliable in research applications [2i]. The observed weakness of the 60 deg./sec. involved knees at baseline in both flexion andft-lbs extension is consistent with current literature [I,20].36 While the PT group p r o d u c e d gains in flexion34 Control strength with training, these gains did not translate 41" to the immediate postoperative period. The PT32 PT groups strength gains from 6 weeks to 3 m o n t h s30 after surgery were significant, but the C groups28 gains were not significant. One w o u l d not expect a26 delayed effect of preoperative physical therapy.24 These differences most likely represent small sample base pre-op* 6wk* 3mo size error and the inability of this study to d e m o n - Fig. 5. Flexion peak torque over time. strate a statistically significant difference for the C
  6. 6. Preoperative PTin PrimaryTKA • Rodgers et al. 419 Table 3. Computed Tomograpby Muscle Area Involved Uninvolved Total T h i g h Muscle Intramuscular Total T h i g h Muscle Intramuscular cm 2 cm 2 Fat cm 2 %Muscle cm 2 cm 2 Fat cm 2 %MuscleControl Preop 261.56 112.52a 25.62 43.02 262.04 113.85 23.85 43.45 6 weeks 244.32 90.12b 27.66 36.89 251.97 111.35 21.85 44.19PT Baseline 285.86 I08.71c 23.49 38.03 298.73 117.04 23.8I 39.18 Preop 284.95 105.31d 24.84 36.96 295.50 114.43 22.88 38.72 6 weeks 266.67 94.00e 25.15 35.25 271.80 110.44 22. l 1 40.63P values avs. b 0.04 *no significant differences p a i r e d t-test cvs. d n.s. dvs. e Repeated measures analysis showed no differ- more significant differences in strength may haveence between the groups, supporting this conten- been present, but not measured. However, we aretion. not aware of an isotonic strength testing apparatus Quadricep strength is essential to immediate post- that is as reliable, safe, and convenient as the Cybexoperative rehabilitation and progress in weight- II isokinetic testing device [23].bearing [22]. Later in rehabilitation, the emergence Overall, the recovery of Both groups to baselineof symmetrical and uniform gait also depends on strength By the 3-month evaluation was quiteincreased quadricep strength [ 1]. Extension strength, remarkable. While Berman measured isokinetichowever, failed to improve with training. Patello- strength after TKA, his initial postoperative measure-femoral pain during testing may have limited perfor- ment was performed from 3 to 6 months aftermance, although in a study of isokinetic perfor- surgery. This is the first study to evaluate isokineticmance of patients with osteoarthritis of the knees, strength of all patients 3 months after surgery andLankhorst et al. [20] felt the influence of pain on document recovery to baseline. It is important totorque was minimal [20]. note that this "recovery" may be more a function of One can also not ignore the effect of specificity of pain relief (allowing a better isokinetic test) thantraining on strength measurement. The physical true strength gain.therapy program utilized predominantly closed- The computed tomography (CT) muscle area datachain, isotonic exercise, while the testing consisted provide more convincing evidence of the positiveof open-chain isokinetic measurement. This factor effect of preoperative physical therapy. While preop-has not been investigated for diseased individuals, erative physical training failed to produce musclebut overwhehning evidence supports exercise-type area increase, these data suggest that, after surgery,specificity regarding isokinetic versus isotonic exer- muscle thigh area may be preserved by preoperativecise for normal individuals [21]. Consequently, physical training. In addition, this study is the first to definitively measure the significant muscle area changes that occur following TKA. It is important to note that the relatively large changes in muscle areacm2 demonstrated By the CT analysis did not correlate120 ~ . _ with the thigh circumference measurement.115 - i Uninvolved In this climate of increasing pressure to limit costs Control and decrease utilization of medical resources, allI10 ~ 4- new treatment interventions will need to be scruti-105 ~, FT nized in this light. In this limited study, no savings in "I100 i 911 i [I Involved Control -O- terms of decreased hospital stay or need for post- hospitalization physical therapy could be demon- strated for the physical therapy. Many intangible variables beyond the control of this study influence PT pre-op 6wk ~ these measures including confounding medical prob- lems, family expectations, living arrangements, and Fig. 7. Computed tomography muscle area over time. even day of the week of surgery.
  7. 7. 420 The Journal of Arthroplasty Vol. 13 No. 4 June-1998 Few investigators h a v e studied the effect of pre- cal analysis, a n d the UNMC D e p a r t m e n t s of Physicaloperative physical t h e r a p y in TKA. W e i d e n h i e l m T h e r a p y a n d Radiology for their assistance in thiset al. [2] investigated p r e o p e r a t i v e isometric exer- study.cise in patients scheduled for u n i c o m p a r t m e n t a lk n e e r e p l a c e m e n t [2]. These authors d e m o n s t r a t e ddecreased self-selected walking speed p r e o p e r a - Referencestively w i t h i m p r o v e m e n t in p a i n a n d perceivedstability, b u t no difference in strength, range of 1. Berman AT, Bosacco SJ, Israelite C: Evaluation ofmotion, or o x y g e n cost of walking. Three m o n t h s total knee arthroplasty using isokinetic testing. Clin Orthop 271:106, I991after surgery, n o differences could be d e m o n s t r a t e d 2. Weidenhielm L, Mattsson E, Brostrom L, Wersall-b e t w e e n the C a n d PT group. These authors con- Robertsson E: Effect of preoperative physiotherapy included their study did not s h o w a n y m a j o r benefit unicompartmental prosthetic knee replacement.f r o m the t h e r a p y tested. DLima et al. [13] recently Scand J Rehab Med 25:33, I993investigated two p r e o p e r a t i v e physical t h e r a p y pro- 3. Martin TP, Gundersen LA, Blevins FT, Coutts RD: Thegrams before TKA. They also failed to d e m o n s t r a t e influence of functional electrical stimulation on thethe value of physical t h e r a p y (either strength train- properties of vastus lateralis fibers following totaling or aerobic conditioning) using the HSS k n e e knee arthroplasty. Scand J Rehab Med 23:207, i991score, Quality of Well-Being survey, and the Arthri- 4. Larsson L, Grimby G, Karlsson J: Muscle strength andtis I m p a c t M e a s u r e m e n t Scale. These i n s t r u m e n t s speed of movement in relation to age and muscleare not designed to m e a s u r e the effects of physical morphology. J Appl Physio146:451, 1978 5. Michelsen CB, Askanazi J, Grump FE, Elsyn D,t h e r a p y and are probably not sensitive e n o u g h to Kinney JM, Stinchfield FE: Changes in metabolismd e m o n s t r a t e significant change. and muscle composition associated with total hip This study is the first to evaluate the effect of replacement. J Trauma 19:29, 1979p r e o p e r a t i v e physical t h e r a p y on TKA using objec- 6. Gotlin RS, Hershkowitz S, Juris PM, Gonzalez EG,tive m e a s u r e m e n t techniques in the i m m e d i a t e Scott WN, Insall JN: Electrical stimulation effect onpostoperative period, but it is not w i t h o u t its limita- extensor lag and length of hospital stay after totaltions. R a n d o m i z a t i o n was n o t possible u n d e r the knee arthroplasty. Arch Phys Med Rehab 75:957,constraints of available funding for the physical 1994t h e r a p y sessions in a single location. The concept of 7. Haug J, Wood LT: Efficacy of neuromuscular stimula-" p r e r a n d o m i z a t i o n " has b e e n validated previously, tion of quadriceps femoris during continuous passiveh o w e v e r [24]. Our e x p e r i m e n t a l design takes this motion following total knee arthroplasty. Arch Physconcept of g r o u p assignment before r e c r u i t m e n t Med Rehab 69:423, 1988 8. Nadler SF, Malanga FA, Zimmerman JR: Continuousone step further by basing it on geographic avail- passive motion in the rehabilitation setting. Am Jability. Phys Med Rehab 72:162, 1995 While this study failed to p r o d u c e convincing 9. Nielsen PT, Rechnagel K, Nielsen S: No effect ofevidence of the benefit of p r e o p e r a t i v e physical continuous passive motion after arthroplasy of thet h e r a p y in TKA using strength m e a s u r e m e n t a n d knee. Acta Orthop Scand 59:580, 1988functional p a r a m e t e r s , it did d e m o n s t r a t e accu- 10. Ritter MA, Gandolf VS, Holston K: Continuous pas-rately the decrease in muscle area following the sive motion versus physical therapy in total kneeprocedure. In addition, physical t h e r a p y m a y help arthroplasty. Clin Orthop 244:239, I989limit this atrophy. The clinical significance of this 11. Ververeli PA, Sutton DC, Hearn SL, Booth RE, EIozackfinding is uncertain. W J, Rothman RR: Continuous passive motion after While 9 of 10 patients in the PT group felt that total knee arthroplasty: analysis of cost and benefits. Clin Orthop 321:208, 1995p r e o p e r a t i v e t h e r a p y was beneficial, the objective 12. Wasilewski SA, Woods LC, Torgerson WR, Healy WL:data do n o t support routine use. The i n c o n v e n i e n c e Value of continuous passive motion in total kneea n d e x p e n s e of a p r e o p e r a t i v e t h e r a p y p r o g r a m arthroplasty. Orthopedics I3:291, 1990c a n n o t be justified based on this study. 13. DLima DD, Colwell DW, Morris BA, Hardwick ME, Kozin F: The effect of preopeative exercise on total knee replacement outcomes. Clin Orthop 326:174, Acknowledgments 1996 14. Fiatarone MA, Marks EC, Ryan ND, Meredith CN, We t h a n k Liz Ruby, of the UNMC D e p a r t m e n t of Lipsitz LA, Evans WJ: High-Intensity strength train-Preventative a n d Societal Medicine for her statisti- ing in nonagenarians. JAMA 263:3029, 1990
  8. 8. Preoperative PTin PrimaryTKA • Rodgers et al. 42115. Fisher NM, Pendergrast DR, Calkins E: Muscle reha- of four models of total knee-replacement prostheses. bilitation in impaired elderly nursing h o m e residents. J Bone Joint Surg [Am] 58:754, i976 Arch Phys Med Rehab 72:18I, 1991 20. Lankhorst GJ, VandeStadt RJ, VanderKorst JK: The16. Frontera WR, Meredith CN, OReilly KP, Knuttgen relationships of functional capacity, pain, and isomet- HG, Evans W J: Strength conditioning in older men: ric and isokinetic torque in osteoarthrosis of the knee. skeletal muscle hypertrophy and improved function. Scand J Rehab Med 17:167, 1985 J Appl Physiol 64:1038, 1988 21. Morrissey MC, Harman EA, Johnson M J: Resistance17. Fisher NM, Pendergrast DR, Gresham GE, Calkins E: training modes: specificity and effectiveness. Med Sci Muscle rehabilitation: its effect on muscular and Sports Exerc 27:648, 1995 functional p e r f o r m a n c e of patients with knee 22. Krackow KA: The technique of total knee arthro- osteoarthritis. Arch Phys Med Rehab 72:367, 1991 plasty, p. 388. CV Mosby, St. Louis, MO, 199018. Minor MA, Hewett JE, Webel RR, Anderson SK, Kay 23. Almekinders LC, Oman J: Isokinetic muscle testing: is DR: Efficacy of physical conditioning exercise in it clinically useful]? J Am Acad Orthop Surg 2:221, 1994 patients with rheumatoid arthrotis and osteoarthritis. 24. Chang RW, Falconer J, Stulberg SD, Arnold W J, Dyer Arthritis R h e u m 32:1396, 1 9 8 9 AR: Prerandomization: an alternative to classic random-i9. Insall JN, Ranawat CS, Aglietti P, Shine J: Comparison ization. J Bone Joint Surg [Am] 72:1451, 1990