Heather M. Holder-Powell, PhD, Olga M. Rutherford, PhD. ABSTRACT. Holder-Powell HM, Rutherford ..... Roy S. Injuries of exercise. Med Clin North Am 1985 ...
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Unilateral Lower Limb Injury: Its Long-Term Effects on Quadriceps, Hamstring, and Plantarflexor Muscle Strength Heather M. Holder-Powell,
PhD, Olga M. Rutherford,
PhD
ABSTRACT. Holder-Powell HM, Rutherford OM. Unilateral lower limb injury: its long-term effects on quadriceps, hamstring, and plantarflexor muscle strength. Arch Phys Med Rehabil 1999;80:717-720. Objective: To ascertain if long-term deficits in quadriceps, hamstring, and plantarflexor muscle strength remain after unilateral lower-limb musculoskeletal injury and to quantify whether improvements in performance continue once a subject concludes rehabilitation and returns to everyday activities. The relation between the size of decrement and limb dominance, type of injury, and time since injury was also considered. Design: Isometric and/or dynamic muscle strength of both legs was measured (using the KinCom 500H isokinetic dynamometer) in 48 subjects. Setting: A physiological laboratory at Brunel University. Patients: Patients were recruited locally via a district general hospital, sports injury clinic, and university. Main Outcome Measures: Muscle strength in the injured limb, reported as a percentage of muscle strength in the uninjured limb. It was assumed that the preinjury state of the injured limb was similar to that of the uninjured limb. Results: Decrements were seen in mean isometric and peak isometric, concentric, and eccentric quadriceps activity (p < .OOOl) and isometric plantarflexor activity (p < .0.5) in the injured limb, with the type of injury influencing the size of the decrement. Minimal difference was found in the hamstring muscles. Conclusions: The decrements in performance in the quadriceps muscle imply that full recovery (as defined by the preinjury state) is frequently not achieved and stress the need for accurate, objective assessment of muscle strength and further investigation into the nature and duration of rehabilitation after musculoskeletal injury. 0 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation
M
USCULOSKELETAL INJURIES of the lower limb are a common occurrence, especially in persons who exercise regularly,’ and patients are frequently referred either directly or indirectly for physiotherapy. Substantial improvements in pain relief, joint mobility, muscle strength, and function are made in the initial rehabilitation period of a few weeks or months. It is
From the Department of Sport Sciences, Brunei University, Middlesex (Dr. Holder-Powell) and Biomedical Sciences, Imperial College School of Medicine, London (Dr. Rutherford), United Kingdom. Submitted for publication October 12, 1998. Accepted in revised form January 22, 1999. Supported in part by Rehabilitation and Medical Research Trust and The Wishbone Trust. No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit upon the authors or upon any organization with which the authors are. associated. Remint reauests to H.M. Holder-Powell. PhD. Detxrtment of Suort Sciences. Bmnel Univekty, Borough Road, Isleworth, ‘Middlesex~kW7 5DU, U&d Kingdom. 0 1999 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation 0003.9993/99/8006-5263$3.00/O
frequently assumed, after the formal period of rehabilitation has concluded, that as the patient becomes more active, recovery will continue until the preinjury state is reached. This assumption, however, may not be the case. In a pilot study of seven subjects with unilateral lower limb injury, Rutherford and colleagues2reported persistent decrements in quadriceps isometric force and cross-sectional area 1 to 5 years after full mobilization. Studies have found that subjects have substantial decrements in muscle strength or size at the time of discharge from formal rehabilitation after lower leg fractures3-‘jand femoral fractures7 Other studies have reported functional and/or strength deficits after knee injuries and/or surgery.“-l3More than 40% of patients who have had lateral ligament injury continue to experience ankle symptoms 1 year after injury.14-16 These studies have concentrated on specific injuries but have not compared the long-term outcome of different injuries at different sites on the lower limb. After many lower limb injuries, patients frequently comment that they are aware of an instability around the knee when descending stairs, a movement that involves eccentric activity of the quadriceps. Previous studies have concentrated on isometric and/or concentric forces only. There remains a lack of information about the long-term strength of different lower limb muscle groups in persons who have had musculoskeletal injury. The long-term outcome with respect to (1) the type of contraction, (2) limb dominance, and (3) the type of injury also remains unclear. The aims of this study were therefore to ascertain (1) whether patients who have sustained lower limb musculoskeletal injuries continue to experience long-term deficits in strength of the knee extensor (quadriceps), knee flexors (hamstrings), and plantarflexor muscles (gastrocnemius and soleus), (2) whether the type of contraction affects the magnitude of the strength deficit, (3) whether the dominance of the injury affects longterm outcome, and (4) whether the outcome is related to the site and nature of the injury. METHODS Criteria for selection. Only subjects with a unilateral musculoskeletal injury, with no neurologic involvement, that required medical treatment were included in the study. The injuries occurred at least 9 months earlier. At the time of testing, subjects had received no medical treatment or physical therapy in the previous 6 months and were pain free. Ethical approval was obtained and all subjects gave written informed consent. Subjects. Subjects were recruited locally from a university population, a district general hospital, and sports clinics. Forty-eight subjects (37 men, 11 women) participated in the study. Dominance was defined as the preferred leg for kicking. Age and time since injury for the subjects are listed in table 1. Types of injury are listed in table 2. All subjects were healthy and active and most participated in sport at a recreational/ university level. Clinical examination. Clinical examination was done to confirm that subjects met the selection criteria. Active and passive ranges of movement of the injured limb were compared Arch
Phys
Med
Rehabil
Vol80,
June
1999
718
EFFECT
Table
1: Subject
Demographics
Characteristics
Mean
injury
(yrs)
Men
SD
2: Type
of Injury
Group Injuries
tendon Knee ligament
Knee Fracture Ankle
9.6
62-l 05
15.1
54-l 01
Phys
and Dominance
“D”
Med
and
in parentheses
Rehabil
n
the quadriceps cartilage
Fractures of the lower Ankle ligament injuries
Number with limb injuries.
Arch
involving
1999
or
injuries
leg (tibia, excluding
indicates
Vol 80, June
muscle
fibula, foot) fractures
the number
of Variation for the Testing Using the KinCom 500H
Group
7 (4D) 22 (15D) 14 (9D) 5 (3D)
of dominant
Procedures
Test
CV%
Peak isometric Concentric Concentric
Quadriceps Quadriceps Plantarflexors
1.59-1.93 1.59-1.78
Injury
Quadriceps
3: Coefficients
Quadriceps Quadriceps
with those of the uninjured limb to confirm that neither knee flexion nor knee extension was too limited for participation in the isokinetic muscle test procedures and that the movements did not elicit any pain. The subject lay supine and actively flexed the hip and knee. With the knee flexed, the subject dorsiflexed and plantarflexed the ankle; these movements were repeated passively and overpressure was applied. With the subject’s eyes closed, joint proprioception and cutaneous sensation were grossly tested. To assessjoint proprioception, the knee was passively flexed or extended and the ankle dorsiflexed or plantarflexed. The subject was asked to report the direction of the movement and the final position of the joint. With the subject supine, cutaneous sensation was tested by random, light brushing of the skin; the subject reported the area where the contact occurred. Measurements. All muscle strength measurements were made using the Kin Corn 500H isokinetic dynamometera with the subject in a sitting position. All dynamic tests for the knee flexors and extensors were carried out with single, noncontinuous maneuvers that were repeated three times; the maximum voluntary peak performance was recorded. For the quadriceps muscle group, isometric, concentric, and eccentric measurements were recorded. The peak isometric force was determined at 70”, SO“,90”, and 100” of knee flexion and the maximum voluntary force was recorded. In a subset of the subjects, selected randomly, the mean isometric force was tested over a lo-second period with the knee at 90” of flexion. The maximum concentric force was recorded as the knee extended from 95” and 15” flexion, at speeds of 30”lsec and 120”lsec. Peak eccentric force was recorded with the limb resisting flexion between 45” and 95” at a speed of 30”lsec. The hamstrings were tested at 30”/sec and 120”/sec concentrically with the knee moving between 15” and 95” flexion. The plantarflexors were tested isometrically with the knee at 90” flexion and the ankle supported on a plinth in a neutral position. The uninjured limb was tested first, followed by the injured limb. The coefficients of variation for the quadriceps and plantarflexor testing procedures were determined by testing six subjects six times on different days (table 3). Statistica analysis. Students’ paired t tests (Excel Astuteb) were used to determine the difference between the injured and uninjured limbs. A one-way analysis of variance (ANOVA) Table
Holder-Powell
Muscle 18-62 0.75-42
.07 .06
82.0 70.8
STRENGTH,
Range
11.0
1.79 1.77
Men Women
MUSCLE
Table
12
9.7
Women Weight (kg)
ON
(n = 48)
33
Age (vs) Time since Height(m)
OF INJURY
7.4 6.4
30”isec 120”isec
7.2 6.4
Eccentric 30”/sec Peak isometric
9.0
(Unistat statistical packagec) was used to determine if there was any difference between the effect of dominance of the injury or type of injury on the extent of the decrement. RESULTS Results are presented with reference to (1) the entire group, (2) the dominance of the injury, and (3) the type of injury. The maximum peak isometric and dynamic quadriceps tests and hamstring tests were attempted by all 48 subjects. One subject failed to complete the eccentric testing procedures because of an inability to perform the maneuver required on either limb. The mean isometric quadriceps tests and the plantarflexor tests were successfully attempted by 31 and 25 subjects, respectively. No difference was seen between the knee angle at which the peak isometric force of the quadriceps was generated in the injured and uninjured limb. Significant deficits were seenin peak and mean isometric and all dynamic tests of quadriceps strength, and in the plantarflexors (table 4). No significant differences were found between the hamstrings of the injured and uninjured sides. Effect of dominance. Thirty-one subjects had received injuries to the dominant limb and 17 to the nondominant limb. Although significant differences were seen between the injured and uninjured limbs in the dominant and nondominant subgroups (table 5), the deficits were of similar extent for both subjects with dominant limb injuries and those with nondominant limb injuries (p > .05). Effect of type of injury. Significant deficits existed in maximum voluntary isometric, concentric, and eccentric strength in the knee and fracture groups and in the maximum peak voluntary isometric and slow concentric action of the subjects with ankle injuries. The decrements in hamstring strength were only found in subjects in the quadriceps group and only 30”lsec (table 6). The largest decrements in quadriceps strength were seen in subjects in the quadriceps group, defined in our study as the group of subjects with injuries that directly affected the quadriceps muscle or tendon. A one-way ANOVA showed that significantly lower quadriceps forces were generated in the quadriceps group when Table
4: Decrements in Muscle Strength of the Hamstrings, and Plantarflexors
Muscle
Group
Test
Quadriceps
(n = 48)
Peak
Quadriceps Quadriceps Quadriceps
(n = 31) (n = 48) (n = 48)
Mean isometric Concentric 30Ysec Concentric 120Vsec
Quadriceps Hamstrings Hamstrings
(n = 47) (n = 48) (n = 48)
Eccentric Concentric Concentric
Plantarflexors
(n = 25)
Quadriceps,
Peak
isometric
30Ysec 30°/sec 120”isec
isometric
Data are reported as mean ? SD. Abbreviation: I/UI%, percentage of the force produced limb compared with that of the uninjured limb. For comparison of I vs UI, * p < .OOOl, + p < .05.
l/UI% 86.9 84.7
t 13.8” 2 16.9*
82.3 88.6 85.9
t 13.0* r+_ 16.39* + 17.7”
96.1 97.2 93.8
” 15.5 + 15.5 + 12.5+
by the injured
EFFECT Table
OF INJURY
5: Comparison of the Decrements in Muscle in Subjects With Dominant and Nondominant
Strength Injuries
(l/Ul%)
WI %
MUSCk?
Group
Dominant
Test
Limb
Nondominant
Quadriceps
Peak isometric
87.7 f 13.9' (n = 31)
85.4
Quadriceps
Mean
87.7
i: 15.1+ (n= 22)
77.6
Quadriceps
Concentric
30”/sec
82.5
i- 13.5* (n = 31)
120”lsec
90.4
isometric
Quadriceps
Concentric
Quadriceps
Eccentric
Hamstrings
Concentric
Hamstrings
ON MUSCLE
Concentric
Plantarflexors
Peak
2 13.8f (n = 17)
t 19.8 (n= 9) 82.1 t 12.5"
+ 16.2+ (n= 31) 83.5 t 20.4”
30Vsec
Limb
85.3
(n= 17) + 16.4*
86.4
(n= 17) k 12.3+
30Vsec
95.8
n=31) + 14.4
(n= 17) 96.7 i- 17.7
120”/sec
(n = 31) 98.4 2 16.9 (n = 31)
(n= 17) 94.9 + 12.8 (n= 17)
94.2
93.1
isometric
2 13.4
(n=
17)
t 11.4 (n=
8)
Data are reported as mean + SD. Abbreviation: WI%, percentage of the force produced by the injured limb compared with that of the uninjured limb. For comparison of I vs UI, * p < .OOOl, + p < ,001, * p < .05.
compared with (1) the knee group for peak and mean isometric forces and (2) the fracture group for mean isometric and eccentric force. In summary, dynamic activity tended to be better preserved than isometric activity in the quadriceps group. Significant decrements existed in quadriceps strength in the fracture and Table
6: Comparison Different Muscle
of the Percentage Decrement (I/UI%) Actions in Different Types of Injury
Quadriceps (n = 7)
Knee (n = 22)
in
Fracture
Ankle
(n = 14)
(n = 5)
Quadriceps peak isometric Quadriceps
71.2
t 9.7’
91.2
2 13.0+
86.8
2 13.9+
89.9
? 5.6+
60.7
+ 13.0’
90.2
? 14.6
85.0
? 13.5*
93.0
2 23.5
30”isec Quadriceps concentric
75.2
t
11.4+
84.8
k 13.7"
80.4
+ 12.9*
86.6
+ 10.6'
120”kec Quadriceps
76.0
? 13.2+
91.9
? 17.1*
88.1
-t 14.0+
93.5
+ 17.8
73.5
i- 13.1+
80.8
t
14.1"
91.7
'-c 11.3*
98.8
k 10.8
concentric 30Ysec
89.8
i
97.5
2 16.0
97.5
t
17.7
94.9
2 14.1
Hamstrings concentric 1 20°/sec
93.8
+ 12.9
97.8
k 15.2
98.9
t
18.0
94.0
+ 16.5
Plantarflexors isometric
90.1
t 6.8
95.0
+ 12.7
91.6
2 15.0
105.4
mean isometric Quadriceps concentric
eccentric 30Vsec Hamstrings
10.2*
Data reported as mean I? SD. Abbreviation: I/UI%, percentage of the force produced limb compared with that of the uninjured limb. ForcomparisonofIvsUI,* p
