Crystal O. Kean

Operative versus Nonoperative Treatment of Acute Achilles Tendon Ruptures A Multicenter Randomized Trial Using Accelerated Functional Rehabilitation

BACKGROUND To date, studies directly comparing the rerupture rate in patients with an Achilles tendon rupture who are treated with surgical repair with the rate in patients treated nonoperatively have been inconclusive but the pooled relative risk of rerupture favored surgical repair. In all but one study, the limb was immobilized for six to eight weeks. Published studies of animals and humans have shown a benefit of early functional stimulus to healing tendons. The purpose of the present study was to compare the outcomes of patients with an acute Achilles tendon rupture treated with operative repair and accelerated functional rehabilitation with the outcomes of similar patients treated with accelerated functional rehabilitation alone. METHODS Patients were randomized to operative or nonoperative treatment for acute Achilles tendon rupture. All patients underwent an accelerated rehabilitation protocol that featured early weight-bearing and early range of motion. The primary outcome was the rerupture rate as demonstrated by a positive Thompson squeeze test, the presence of a palpable gap, and loss of plantar flexion strength. Secondary outcomes included isokinetic strength, the Leppilahti score, range of motion, and calf circumference measured at three, six, twelve, and twenty-four months after injury. RESULTS A total of 144 patients (seventy-two treated operatively and seventy-two treated nonoperatively) were randomized. There were 118 males and twenty-six females, and the mean age (and standard deviation) was 40.4 ± 8.8 years. Rerupture occurred in two patients in the operative group and in three patients in the nonoperative group. There was no clinically important difference between groups with regard to strength, range of motion, calf circumference, or Leppilahti score. There were thirteen complications in the operative group and six in the nonoperative group, with the main difference being the greater number of soft-tissue-related complications in the operative group. CONCLUSIONS This study supports accelerated functional rehabilitation and nonoperative treatment for acute Achilles tendon ruptures. All measured outcomes of nonoperative treatment were acceptable and were clinically similar to those for operative treatment. In addition, this study suggests that the application of an accelerated-rehabilitation nonoperative protocol avoids serious complications related to surgical management.

Minimal Detectable Change in Quadriceps Strength and Voluntary Muscle Activation in Patients With Knee Osteoarthritis

OBJECTIVE To examine the test-retest reliability and quantify the minimal detectable change (MDC) in quadriceps strength and voluntary activation in patients with knee osteoarthritis (OA). DESIGN Repeated measures over a 1-week interval. SETTING Tertiary care center. PARTICIPANTS A convenience sample of patients (N=20) diagnosed with knee OA. INTERVENTION Isokinetic and isometric quadriceps strength testing and voluntary quadriceps activation testing using interpolated twitch technique. MAIN OUTCOME MEASURES Peak isokinetic and isometric knee extension torque (Nm) and percentage of voluntary quadriceps activation (%). RESULTS The mean differences with 95% confidence intervals between the 2 test sessions for quadriceps isokinetic strength, isometric strength, and percent of voluntary activation were -4.34Nm (-14.01 to 5.34Nm), 1.56Nm (-5.56 to 8.68Nm), and 1.34% (-.53 to 3.22%), respectively. The intraclass correlation coefficients for all measures ranged from .93 to .98. The standard errors of measurement (SEMs) for quadriceps isokinetic and isometric strength were 14.57Nm and 10.76Nm, respectively. The SEM for percentage of voluntary activation was 2.84%. Based on these values, the MDCs were 33.90Nm, 25.02Nm, and 6.60% for quadriceps isokinetic strength, isometric strength, and percentage of voluntary activation, respectively. CONCLUSIONS Maximal quadriceps isokinetic strength, isometric strength, and percentage of voluntary activation measures demonstrate excellent test-retest reliability in patients with knee OA. In addition to research applications, the present findings suggest these measures are appropriate for use when evaluating change in neuromuscular function of the quadriceps in individual patients.

Resistance training for medial compartment knee osteoarthritis and malalignment.

PURPOSES 1) To evaluate the effects of a 12-wk high-intensity knee extensor and flexor resistance training program on strength, pain, and adherence in patients with advanced knee osteoarthritis and varus malalignment and 2) to generate pilot data for change in dynamic knee joint load, patent-reported outcomes, and self-efficacy after training. METHODS Fourteen patients (48.35 +/- 6.51 yr) with radiographically confirmed medial compartment knee osteoarthritis and varus malalignment of the lower limb were recruited from a surgical waiting list for high tibial osteotomy. Participants completed a high-intensity isokinetic resistance training program three times per week for 12 wk. Knee extensor and flexor strength were assessed every third week, whereas pain and adherence were recorded at every training session. The external knee adduction moment during the gait, the 6-min-walk test, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the Arthritis Self-Efficacy Scale (ASES) were also evaluated before and after training. RESULTS Significant improvements in knee extensor and flexor strength were observed without increases in pain during or after training. Adherence to the high-intensity program was high. No significant changes were observed for dynamic knee joint load or the KOOS. There was a significant increase in the function subscale of the ASES only. CONCLUSIONS These findings suggest that patients with advanced knee osteoarthritis and malalignment can experience substantial gains in strength after a high-intensity resistance training program without concomitant increases in pain, adverse events, or compromised adherence. These findings provide support for future clinical trials with longer-term outcomes.

Comparison of peak knee adduction moment and knee adduction moment impulse in distinguishing between severities of knee osteoarthritis

BACKGROUND The peak knee adduction moment is a valid proxy for medial knee joint loading. However as it only measures load at one instance of stance, knee adduction moment impulse, a measure that takes into account both the magnitude and duration of the stance phase, may provide more comprehensive information. This study directly compared the abilities of peak knee adduction moment and knee adduction moment impulse to distinguish between knee osteoarthritis severities. METHODS 169 participants with medial knee osteoarthritis completed radiographic and magnetic resonance imaging, the Western Ontario and McMaster Universities Arthritis Index to assess pain and a three-dimensional gait analysis. Participants were classified using four dichotomous classifications: Kellgren-Lawrence grading, alignment, medial tibiofemoral bone marrow lesions, and pain. FINDINGS When using Kellgren-Lawrence grade and alignment classifications, the area under the receiver operator curves were significantly greater for knee adduction moment impulse than for peak knee adduction moment. Based on analysis of covariance, knee adduction moment impulse was significantly different between Kellgren-Lawrence grade and alignment groups while peak knee adduction moment was not significantly different. Both peak knee adduction moment and knee adduction moment impulse distinguished between bone marrow lesion severities while neither measure was significantly different between pain severity groups. INTERPRETATIONS Findings suggest knee adduction moment impulse is more sensitive at distinguishing between disease severities and may provide more comprehensive information on medial knee joint loading. Future studies investigating biomechanics of knee osteoarthritis should include knee adduction moment impulse in conjunction with peak knee adduction moment.

Alignment, body mass and their interaction on dynamic knee joint load in patients with knee osteoarthritis

OBJECTIVE To examine the interaction and relative contributions of frontal plane alignment and body mass on dynamic knee joint loading in patients with knee osteoarthritis (OA). METHODS We completed three-dimensional gait analyses and hip-to-ankle standing anteroposterior radiographs on 487 patients with knee OA referred to a tertiary care center specializing in orthopaedics. RESULTS Using sequential (hierarchical) linear regression, the interaction term (mechanical axis anglexmass) contributed significantly (P<0.001) to a model (total adjusted R(2)=0.70) predicting the external knee adduction moment, that included mechanical axis angle (R(2)=0.37) and mass (R(2)=0.06) while controlling for age, sex, height, Kellgren and Lawrence grade, pain score during walking, gait speed, toe out angle and trunk lean (R(2)=0.25). When the sample was split into tertiles for mass, mechanical axis angle accounted for 32-54% of explained variance in knee adduction moment. In the tertile with greatest mass, results suggest a 3.2 N m increase in knee load for every 1 degrees increase in varus alignment. When split into tertiles for mechanical axis angle, mass accounted for 6-10% of explained variance in the knee adduction moment. In the tertile with the most varus alignment, results suggest a 0.4 N m increase in knee load for every 1 kg increase in mass. CONCLUSION Our findings describe the interaction between alignment and body mass on dynamic knee joint loading, with the association between alignment and load highest in patients with the highest mass. Our findings also emphasize the role of malalignment on knee load at all levels of mass, and have implications for better understanding risk factors and intervention strategies for knee OA.

Effects of a modified shoe on knee load in people with and those without knee osteoarthritis

OBJECTIVE To evaluate the effects of a modified shoe that incorporates both lateral wedging and a variable-stiffness sole on knee joint loading in 3 populations: individuals with symptomatic and radiographic knee osteoarthritis (OA), asymptomatic overweight individuals, and asymptomatic healthy weight individuals. METHODS Ninety participants (30 per group) underwent a 3-dimensional gait analysis across 3 test conditions: modified shoes, standard control shoes, and barefoot. For each condition, the first peak knee adduction moment (KAM) and knee flexion moment (KFM) (both expressed as Nm/[body weight × height]%) as well as the KAM impulse (expressed as Nm.s/[body weight × height]%) were determined. RESULTS The modified shoes significantly reduced the peak KAM as compared to the control shoes in both the OA (P = 0.002) and the overweight (P = 0.03) groups. In the OA group, there was no significant difference in peak KAM when walking in the modified shoe as compared to walking barefoot. In the overweight and the healthy weight groups, the peak KAM when walking in the modified shoe was significantly higher than that when walking barefoot (P < 0.001). Irrespective of group, the KAM impulse was significantly reduced when walking in the modified shoe as compared to the control shoe (P < 0.001) and was significantly higher during both shoe conditions as compared to walking barefoot (P < 0.001). There was no change in the KFM between walking conditions for any group. CONCLUSION The findings illustrate that a shoe incorporating both a lateral wedge and a variable-stiffness sole can significantly reduce medial knee joint load. Further research examining the effects of these shoes on pain, function, and structural changes in the joint is warranted.

Moments and Muscle Activity after High Tibial Osteotomy and Anterior Cruciate Ligament Reconstruction

PURPOSES To evaluate the effects of simultaneous high tibial osteotomy (HTO) and anterior cruciate ligament (ACL) reconstruction on 1) the external knee adduction moment, 2) the external knee flexion and extension moments, and 3) the quadriceps, hamstrings, and gastrocnemius muscle activity during walking. METHODS Twenty-one patients with varus malalignment of the lower limb, medial compartment knee osteoarthritis, and concomitant anterior cruciate ligament (ACL) deficiency were tested before and 1 yr after undergoing simultaneous medial opening wedge high tibial osteotomy (HTO) and ACL reconstruction during a single operation. Three-dimensional kinetic and kinematic data were used to calculate external coronal and sagittal moments about the knee. EMG data from the quadriceps, hamstrings, and gastrocnemius were used to determine coactivation ratio and activation patterns. RESULTS Neutral alignment and knee stability were achieved in all patients after surgery. The peak knee adduction moment decreased from 2.88 +/- 0.57 to 1.71 +/- 0.56%BW x Ht (P < 0.001). The early stance knee flexion moment decreased from 1.95 +/- 1.89 to 0.88 +/- 1.17%BW x Ht (P < 0.01). The late stance knee extension moment increased from 1.83 +/- 1.53 to 2.76 +/- 1.22%BW x Ht (P < 0.001). There were no significant differences in muscle coactivation or muscle activation patterns (P > 0.05). CONCLUSIONS Improving lower limb alignment and knee stability significantly alters the coronal and the sagittal moments about the knee during walking, without apparent changes in muscle activation patterns.

Five-year changes in gait biomechanics after concomitant high tibial osteotomy and ACL reconstruction in patients with medial knee osteoarthritis.

Background: Concomitant high tibial osteotomy (HTO) and anterior cruciate ligament (ACL) reconstruction is a combined surgical procedure intended to improve kinematics and kinetics in the unstable ACL-deficient knee with varus malalignment and medial compartment knee osteoarthritis (OA). Purpose: To investigate 5-year changes in gait biomechanics as well as radiographic and patient-reported outcomes bilaterally after unilateral, concomitant medial opening wedge HTO and ACL reconstruction. Study Design: Controlled laboratory study. Methods: A total of 33 patients (mean ± SD age, 40 ± 9 years) with varus malalignment (mean mechanical axis angle, −5.9° ± 2.9°), medial compartment knee OA, and ACL deficiency completed 3-dimensional gait analysis preoperatively and 2 and 5 years postoperatively. Primary outcomes were the peak external knee adduction (first peak) and flexion moments. Secondary outcomes were the peak external knee extension and transverse plane moments, peak knee angles in all 3 planes, radiographic static knee alignment measures (mechanical axis angle and posterior tibial slope), and the Knee injury and Osteoarthritis Outcome Score (KOOS). Results: There was a substantial decrease in the knee adduction moment in the surgical limb (%BW × H, −1.49; 95% CI, −1.75 to −1.22) and a slight increase in the nonsurgical limb (%BW × H, 0.16; 95% CI, 0.03 to 0.30) from preoperatively to 5 years postoperatively. There was also a decrease in the knee flexion moment for both the surgical (%BW × H, −0.67; 95% CI, −1.19 to −0.15) and nonsurgical limbs (%BW × H, –1.06; 95% CI, –1.49 to −0.64). Secondary outcomes suggested that substantial improvements were maintained at 5 years, although smaller declines were observed in several measures and in both limbs from 2 to 5 years. Conclusion: Changes in the peak external moments about the knee in all 3 planes during walking were observed 5 years after concomitant medial opening wedge HTO and ACL reconstruction. These findings are consistent with an intended, sustained shift in the mediolateral distribution of knee loads. Clinical Relevance: These findings suggest that concomitant HTO and ACL reconstruction results in substantial changes in gait biomechanics. Future clinical research comparing treatment strategies is both warranted and required for this relatively uncommon but seemingly biomechanically efficacious procedure.

Modified walking shoes for knee osteoarthritis: Mechanisms for reductions in the knee adduction moment

The objective of this study was to examine mechanisms underpinning the reduction in knee adduction moment (KAM) and changes in frontal plane knee-ground reaction force (GRF) lever arm with a modified shoe that incorporates both a variable-stiffness sole and lateral wedging. Thirty individuals with symptomatic knee osteoarthritis (OA) and 30 overweight asymptomatic individuals underwent gait analyses wearing modified and standard shoes. In both groups, there was a decrease in the lever arm (p<0.001), and a lateral shift in the center of pressure (COP) offset (p ≤ 0.001). There was no change in frontal plane or medial-lateral GRF magnitudes, lateral trunk lean or stance duration in either group. There was no significant change in the frontal plane hip-knee-ankle angle in the OA group but a significant decrease in the overweight group (p=0.003). In both groups, changes in lever arm and frontal plane GRF magnitude predicted change in peak KAM (p<0.01), but only change in lever arm predicted change in KAM impulse (p<0.001). In the OA group, changes in COP offset and medial-lateral GRF magnitude predicted change in lever arm (p<0.05), whereas changes in trunk lean and hip-knee-ankle angle predicted change in lever arm in the overweight group (p=0.01). In conclusion, the change in lever arm contributed the most to explaining change in KAM parameters with modified shoes. The change in the lever arm was driven by changes evident at the foot in the OA participants (COP and medial-lateral GRF), and by more proximal changes (hip-knee-ankle angle and trunk lean) in the overweight group.

Relationship between hip abductor strength and external hip and knee adduction moments in medial knee osteoarthritis

BACKGROUND Alterations in hip abductor strength and hip and knee adduction moments during gait are associated with knee osteoarthritis. This study examines the relationship between hip abductor strength and hip and knee adduction moments during gait in individuals with symptomatic medial knee osteoarthritis. METHODS Ninety-nine participants underwent maximal isometric hip abductor strength testing and 3D gait analysis. Pearson correlations examined relationships between non-normalized maximal hip abductor strength (Nm), peak external hip and knee adduction moments (Nm) and knee adduction moment impulse (Nm∙s). Linear regressions examined these relationships while controlling for body size (height and mass) and walking speed. FINDINGS Positive relationships existed between non-normalized hip abductor strength and hip and knee adduction moments (r=0.28 and 0.37, respectively, p<0.01) as well as the knee adduction moment impulse (r=0.47, p<0.01). However, after controlling for body size and walking speed, hip abductor strength was not a significant predictor of hip or knee adduction moments (B=-0.08, and 0.04, respectively, p>0.05) but was a significant predictor of knee adduction moment impulse (B=0.05, p=0.005), explaining 6% of the variance. INTERPRETATION While a significant relationship between hip abductor strength and knee adduction moment impulse was noted, hip abductor strength only explained a small amount of variance in the impulse. Our findings support previous research of healthy individuals and those with mild to moderate knee osteoarthritis and suggests hip abductor strength has little influence on hip and knee adduction moments during gait.