1. 1Student at School of Physiotherapy - University of Eastern Piedmont, Novara, Italy.
2Laboratory of Ergonomics and Musculoskeletal Disorders Assessment, Istituti Clinici Scientifici Maugeri SpA SB - IRCCS, Veruno (NO), Italy.
3Student at School of Physiotherapy, University of Eastern Piedmont, Fossano (CN), Italy
4Unit of Rehabilitation and Functional Recovery, Casa di Cura La Residenza, Rodello (CN), Italy
Background and Objective
The full recovery of strength and function after total knee arthroplasty (TKA) is uncommon,1,2 and patients are frequently
exposed to future disability. Despite these known impairments and activity limitations, there is a lack of established
standards for prescribing exercise paradigms.3 However, there is preliminary evidence that early, progressive high-intensity
rehabilitation can lead to better outcomes.4
Aim of this study was to analyze the safety and effects of a three-weeks, high-load (HI) strength training compared to
controls who underwent a low-intensity (LI) rehabilitation program.
Material and Methods
A total of 39 inpatients with primary unilateral TKA were
recruited in two rehabilitation institutes, and randomized to
the HI (N=18) or LI (N=21) group. A sample size of 18
subject per group was needed. Both groups received a
comprehensive low-intensity treatment aimed to improve
strength, ROM, gait, and function. In addition, the HI group
included two high-intensity strength exercises (leg extension
and squat) three times a week.5
Patients were assessed by means of maximal quadriceps
strength in open and closed kinetic chain. The two groups
were compared by a two-ways ANOVA. Any complaint
(increase of pain/swelling or decreased of walking
endurance/knee ROM) was also recorded. Safety was
assessed with the percentage of dropout, defined as the ratio
between the number of patients who withdrew from
treatment and the number of patient enrolled in the same
group.
Marivo Simone1, PTs; Vercelli Stefano2, PhD PT; Sartorio Francesco2, MSc PT;
Morra Valentina3 PTs, Piano Leonardo4 OMPT
Results
At discharge, the HI group had greater maximal quadriceps
strength (Table 1) in both the leg extension (p<0.05) and
squat (p<0.01) compared to the control group (Figure 1). The
high-intensity exercises were well tolerated, and no subject
withdrew from treatment.
References
1-Noble PC, Gordon MJ, Weiss JM, Reddix RN, Conditt MA, Mathis KB. Does total knee replacement restore normal knee function? Clin Orthop Relat Res. 2005;157-165.
2-Silva M, Shepherd EF, Jackson WO, Pratt JA, McClung CD, Schmalzried TP. Knee strength after total knee arthroplasty. J Arthroplasty. 2003;18:605-611.
3-Pozzi F, Snyder-Mackler L, Zeni J. Physical exercise after knee arthroplasty: a systematic review of controlled trials. Eur J Phys Rehabil Med. 2013;49(6):877-92.
4-Bade MJ, Stevens-Lapsley JE. Early high-intensity rehabilitation following total knee arthroplasty improves outcomes. J Orthop Sports Phys Ther 2011;41:932-41.
5-American College of Sports Medicine. American College of Sports Medicine position stand. Progression models in resistance training for healthy adults. Med Sci Sports
Exerc. 2009;41(3):687-708. doi: 10.1249/MSS.0b013e3181915670.
FEASIBILITY, SAFETY, AND EFFECTS OF EARLY HIGH-INTENSITY
STRENGTH EXERCISES FOLLOWING TOTAL KNEE REPLACEMENT:
A RANDOMIZED CONTROLLED TRIAL
Discussion
Results indicate that the addition of high-intensity
exercises initiated early in the course of recovery after
TKA led to superior strength outcomes, without leading to
increase of pain, swelling or decrease of knee
performances in this group of patients.
The key difference between the 2 programs was the level
of intensity chosen for resistive strength training, and it is
likely that treatment intensity was the primary driver of the
differences in outcomes between groups. Safety of HI
exercises was demonstrated by the absence of difference
in dropout ratio or symptoms’ intensity between groups.
Conclusions
Introducing progressive submaximal exercise after TKA
leads to increased muscular strength with no impairments
that may slow down the recovery process or lengthen the
time of hospitalization. The implementation of more
intense interventions should be considered.
Figure 1. Comparison of strength tests between groups over time
(Tukey box plots). On the left is shown the maximal strength in the leg
extension test, expressed in kilograms; on the right, the maximum
number of repetitions executed in the squat test (the minimum height
recorded for each patient during the squat test at admission was
maintained at discharge). Abbreviations: HI, high-intensity group; LI,
low-intensity group; LE_t0, Leg Extension at admission; LE_t1, Leg
Extension at discharge; Squat_t0, Squat test at admission; Squat_t1,
Squat test at discharge; *, statistical significance at p<0.05; **,
statistical significance at p<0.01. Boxes are the first and third
quartiles, the band inside the box is the mean, the whiskers represent
the lowest value still within 1.5 IQR of the lower quartile, and the
highest value still within 1.5 IQR of the upper quartile.
Table 1. Abbreviations: HI, high-intensity rehabilitation group; LI, low-
intensity rehabilitation group; SD, standard deviation; T0, first day
assessment; T1, last day assessment, Leg extension, maximal
strength in open kinetics chain on leg extension machine expressed in
KG; Squat, maximal strength in closed kinetic chain expressed in lower
height maximum repetition in squat exercise.
Leg extension
T0 T1
Group Mean (SD) p25 p75 Mean (SD) p25 p75
HI 5,1 (3,25) 2,3 6,3 11,6 (4,3) 8,2 14,3
LI 3,27 (3,26) 1,3 4,6 7,02 (4,89) 3,5 9
Squat
T0 T1
Group Mean (SD) p25 p75 Mean (SD) p25 p75
HI 11,25 (3,71) 8,5 13 30 (10,68) 21 40
LI 11,52 (6,87) 6 14 22,38 (10,85) 12 30