Influence of Total Knee Arthroplasty on Gait Mechanics of the Replaced and Non-Replaced Limb During Stair Negotiation

Investigation of Biomechanical Differences in Level Walking between Patients with Bilateral and Unilateral Total Knee Replacements

Due to the high risk of a bilateral total knee arthroplasty (TKR) following unilateral TKR, this study was performed to investigate bilateral TKR patients. Specifically, we examined biomechanical differences between the first replaced and second replaced limbs of bilateral patients. Furthermore, we examined bilateral TKR effects on hip, knee, and ankle biomechanics, compared to the replaced and non-replaced limbs of unilateral patients. Eleven bilateral patients (70.09 ± 5.41 years, 1.71 ± 0.08 m, 91.78 ± 13.00 kg) and fifteen unilateral TKR patients (65.67 ± 6.18 years, 1.73 ± 0.10 m, 87.72 ± 15.70 kg) were analyzed while performing level walking. A repeated measures one-way ANOVA was performed to analyze between-limb differences within the bilateral TKR group. A 2 × 2 (limb × group) ANOVA was used to determine differences between bilateral and unilateral patients. Our results showed that the second replaced limb exhibited a lower peak initial-stance knee extension moment than the first replaced limb. No other kinematic or kinetic differences were found. Bilateral patients exhibited lower initial-stance knee extension moments, knee abduction moments, and dorsiflexion moments, compared to unilateral patients. Bilateral patients also exhibited lower push-off peak hip flexion moments and vertical GRF. The differences between the first and second replaced limbs of bilateral patients may indicate different adaptation strategies used following a second TKR. The significant group differences indicate that adaptations are different between these groups, and it is not recommended to use patients with unilateral and bilateral TKR together in gait analyses.

Do Interlimb Knee Joint Loading Asymmetries Persist throughout Stance during Uphill Walking Following Total Knee Arthroplasty?

The purpose of this study was to determine differences in total (TCF), medial compartment (MCF), and lateral compartment (LCF) tibiofemoral joint compressive forces and related muscle forces between replaced and non-replaced limbs during level and uphill walking at an incline of 10°. A musculoskeletal modeling and simulation approach using static optimization was used to determine the muscle forces and TCF, MCF, and LCF for 25 patients with primary TKA. A statistical parametric mapping repeated-measures ANOVA was conducted on knee compressive forces and muscle forces using statistical parametric mapping. Greater TCF, MCF, and LCF values were observed throughout the loading response, mid-stance, and late stance during uphill walking. During level walking, knee extensor muscle forces were greater throughout the first 50% of the stance during level walking, yet greater during uphill walking during the last 50% of the stance. Conversely, knee flexor muscle forces were greater through the loading response and push-off phases of the stance. No between-limb differences were observed for compressive or muscle forces, suggesting that uphill walking may promote a more balanced loading of replaced and non-replaced limbs. Additionally, patients with TKA appear to rely on the hamstrings muscle group during the late stance for knee joint control, thus supporting uphill walking as an effective exercise modality to improve posterior chain muscle strength.

Tibiofemoral compressive force during downhill walking in patients with primary total knee arthroplasty: A statistical parametric mapping approach

BACKGROUND

Downhill walking is a necessary part of daily life and an effective activity in post-operative rehabilitation following total knee arthroplasty. The purpose of this study was to determine differences in the behavior of total, medial, and lateral tibiofemoral compressive forces as well as knee extensor and flexor muscle forces between different limbs of patients with total knee arthroplasty (replaced, non-replaced) during downhill and level walking.

METHODS

Musculoskeletal modeling and simulation were implemented to determine muscle forces and tibiofemoral compressive forces in 25 patients with total knee arthroplasty. A 2 × 2 [Limb (replaced, non-replaced) × Slope (0°, 10°)] Statistical parametric mapping repeated measures analysis of variance was conducted on selected variables.

FINDINGS

Statistical parametric mapping did not identify any between-limb differences for compressive or muscle forces. Differences in joint compressive and muscle forces persisted throughout different intervals of stance-phase between level and downhill walking. Knee extensor muscle forces were distinctly greater during level walking for nearly all of stance phase. Knee flexor muscle force was greater during downhill walking for >60% of stance. Statistical parametric mapping did identify regions of significance between level and downhill walking that coincided temporally (near loading response and push off) with peak joint moment and joint compressive forces traditionally reported using discrete variable analyses.

INTERPRETATION

Downhill walking may be a safe and useful rehabilitation tool for post-knee arthroplasty rehabilitation that will not disproportionally load either the replaced or the non-replaced joint and where the quadriceps muscles can be strengthened during a gait-specific task.

Better PROMs and higher return-to-sport rate after modular bicompartmental knee arthroplasty than after total knee arthroplasty for medial and patellofemoral compartment osteoarthritis

Background

Theoretical advantages of bicompartmental knee arthroplasty (BKA) over total knee arthroplasty (TKA) for bicompartmental (medial combined with patellofemoral) osteoarthritis (OA) are still unclear. This study aimed to compare patient-reported outcome measures (PROMs) and return-to-sport (RTS) rate between modular BKA and TKA in early follow-up.

Methods

Twenty-five consecutive modular BKA cases with a minimum 2-year follow-up were matched with 50 TKA cases at 1:2 ratio. Demographic data and preoperative functional scores, including the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Knee Society Scores (KSSs), were analyzed to ensure comparability. Postoperative WOMAC score, KSS, range of motion (ROM), Forgotten Joint Score-12 (FJS-12), and RTS rates were compared. Operative time and blood loss were also analyzed.

Results

Significant differences in the WOMAC-function (median 97.1 vs. 89.7, p < 0.001) and KSS-function (median 90.0 vs. 80.0, p = 0.003) scores were identified between the BKA and TKA groups. ROM was significantly greater in the BKA group than in the TKA group (median 125.0° vs. 120.0°, p = 0.004), in addition to the FJS-12 (median 89.6 vs. 53.1, p < 0.001). The overall RTS rate was significantly higher in the BKA group than in the TKA group (71.6% vs. 56.5%, p = 0.039). Operative time was significantly longer in the BKA group than in the TKA group (median 105.0 vs. 67.5 min, p < 0.001), but blood loss was similar (median 557.6 vs. 450.7 ml, p = 0.334).

Conclusion

Modular BKA demonstrated better functional recovery, better joint perception, and higher RTS rate than TKA; thus, modular BKA can be a good alternative for bicompartmental OA.

Medial and Lateral Tibiofemoral Compressive Forces in Patients Following Unilateral Total Knee Arthroplasty During Stationary Cycling

Patients following unilateral total knee arthroplasty (TKA) display interlimb differences in knee joint kinetics during gait and more recently, stationary cycling. The purpose of this study was to use musculoskeletal modeling to estimate total, medial, and lateral tibiofemoral compressive forces for patients following TKA during stationary cycling. Fifteen patients of unilateral TKA, from the same surgeon, participated in cycling at 2 workrates (80 and 100 W). A knee model (OpenSim 3.2) was used to estimate total, medial, and lateral tibiofemoral compressive forces for replaced and nonreplaced limbs. A 2 × 2 (limb × workrate) and a 2 × 2 × 2 (compartment × limb × workrate) analysis of variance were run on the selected variables. Peak medial tibiofemoral compressive force was 23.5% lower for replaced compared to nonreplaced limbs (P = .004, G = 0.80). Peak medial tibiofemoral compressive force was 48.0% greater than peak lateral tibiofemoral compressive force in nonreplaced limbs (MD = 344.5 N, P < .001, G = 1.6) with no difference in replaced limbs (P = .274). Following TKA, patients have greater medial compartment loading on their nonreplaced compared to their replaced limbs and ipsilateral lateral compartment loading. This disproportionate loading may be cause for concern regarding exacerbating contralateral knee osteoarthritis.

Altered biomechanics in bilateral total knee replacement patients during stair negotiation

BACKGROUND

Many total knee replacement (TKR) patients need to have a contralateral knee replacement. Biomechanical differences between first and second replaced limbs of bilateral TKR have not been examined during stair negotiation. Additionally, it is unknown whether hip and ankle biomechanics of bilateral patients are altered. We examined hip, knee, and ankle biomechanics of first and second replaced limbs bilateral patients, as well as replaced and non-replaced limbs of unilateral patients, during stair ascent and descent.

METHODS

Eleven bilateral TKR patients (70.09 ± 5.41 years, 1.71 ± 0.08 m, 91.78 ± 13.00 kg) and 15 unilateral TKR patients (64.93 ± 5.11 years, 1.75 ± 0.09 m, 89.18 ± 17.55 kg) were recruited. Patients performed three to five trials of stair ascent and descent. The second step, during ascent, was the step of interest when analyzing each limb. A 2 × 2 (limb × group) analysis of variance was performed to determine differences between limbs and groups.

RESULTS

During ascent, bilateral patients exhibited decreased peak loading-response knee extension (KEM) and push-off plantarflexion moments. Unilateral replaced limb KEM was lower than non-replaced limbs. During descent, bilateral patients descended the staircase significantly slower, had lower peak loading-response vertical ground reaction force and KEM, and push-off KEM. Bilateral patients had higher peak loading-response hip extension and push-off plantarflexion moments, and increased knee adduction ROM, compared with unilateral TKA patients.

CONCLUSIONS

Bilateral patients exhibited similar hip, knee, and ankle joint moments between first and second replaced limbs. Substantial differences in hip, knee, and ankle biomechanics during stair negotiation in bilateral patients compared with unilateral patients may indicate a more complex adaptation strategy present in these patients.

Principal Component Analysis of Knee Joint Differences Between Bilateral and Unilateral Total Knee Replacement Patients During Level Walking

Many unilateral total knee replacement (TKR) patients will need a contralateral TKR. Differences in knee joint biomechanics between bilateral patients and unilateral patients are not well established. The purpose of this study was to examine knee joint differences in level walking between bilateral and unilateral patients, and asymptomatic controls, using principal component analysis. Knee joints of 1st replaced limbs of 15 bilateral patients (69.40 ± 5.04 years), 15 replaced limbs of unilateral patients (66.47 ± 6.15 years), and 15 asymptomatic controls (63.53 ± 9.50 years) were analyzed during level walking. Principal component analysis examined knee joint sagittal- and frontal-plane kinematics and moments, and vertical ground reaction force (GRF). A one-way analysis of variance analyzed differences between principal component scores of each group. TKR patients exhibited more flexed and abducted knees throughout stance, decreased sagittal knee range of motion (ROM), increased early-stance adduction ROM, decreased loading-response knee extension and push-off knee flexion moments, decreased loading-response and push-off peak knee abduction moment (KAbM), increased KAbM at midstance, increased midstance vertical GRF, and decreased loading-response and push-off vertical GRF. Additionally, bilateral patients exhibited reduced sagittal knee ROM, increased adduction ROM, decreased sagittal knee moments throughout stance, decreased KAbM throughout stance, an earlier loading-response peak vertical GRF, and a decreased push-off vertical GRF, compared to unilateral patients. TKR patients, especially bilateral patients had stiff knee motion in the sagittal-plane, increased frontal-plane joint laxity, and a quadriceps avoidance gait.

Are Medial and Lateral Tibiofemoral Compressive Forces Different in Uphill Compared to Level Walking for Patients Following Total Knee Arthroplasty?

The purpose of this study was to determine how tibiofemoral joint compressive forces and knee joint-spanning muscle forces during uphill walking change compared to level walking in patients with total knee arthroplasty (TKA). A musculoskeletal model capable of resolving total (TCF), medial (MCF), and lateral (LCF) tibiofemoral compressive forces was used to determine compressive forces and muscle forces during level and uphill walking on a 10 deg incline for twenty-five post-TKA patients. A 2 × 2 (slope: level and 10 deg × limb: replaced and nonreplaced) repeated measures analysis of variance was used to detect differences in knee contact forces between slope and limb conditions and their interaction. Peak loading-response TCF, MCF, and LCF were greater during uphill walking than level walking for nonreplaced limbs. During uphill walking, peak loading-response TCF was smaller in replaced limbs compared to nonreplaced limbs with no change in MCF or LCF. Peak knee extension moment and knee extensor muscle force were smaller in replaced limbs compared to nonreplaced limbs during uphill walking. During level walking, replaced and nonreplaced limbs experienced rather equal joint loading; however, replaced limb experienced reduced joint loading during uphill walking. Differences in joint loading between replaced and nonreplaced limbs were not present during level walking, suggesting compensation from the replaced limb during the more difficult task. Uphill walking following TKA promotes more balanced loading of replaced limbs during stance; however, these benefits may come at the expense of increased loading on nonreplaced limbs.

Dynamic stability during stair negotiation after total knee arthroplasty

BACKGROUND

The assessment of dynamic stability is crucial for the prevention of falls in the elderly and people with functional impairments. Evidence that total knee arthroplasty improves balance in patients with severe osteoarthritis is scarce and no information exists about how the surgery affects dynamic stability during stair negotiation.

METHODS

This study aims to investigate if patients before and one year after surgery are less stable compared to asymptomatic controls. Seventeen control and twenty-seven patient participants with end-stage knee osteoarthritis that were scheduled to undergo unilateral total knee arthroplasty were recruited in this study. Participants' assessment was carried out by means of marker-based optical full-body motion capture with force platforms. The extrapolated Centre of mass and the margin of stability metrics were used to examine dynamic stability during stair ascent and descent.

FINDINGS

Patient participants, during both pre-operative and post-operative assessments, were equally balanced to the asymptomatic controls during stair gait (p > .188). Additionally, the patients' overall stability did not improve significantly one year after arthroplasty surgery (p > .252).

INTERPRETATION

Even if pain from arthritis and fear of falling is decreased following surgery, our results indicate that stability in stair walking in not affected by osteoarthritis and total knee arthroplasty.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02422251.

Overground Walking Biomechanics of Dissatisfied Persons With Total Knee Replacements

Patient dissatisfaction following total knee replacement (TKR) procedures is likely influenced by both subjective and objective aspects. Increased pain and reduced performance on clinical tests have been shown in persons who are dissatisfied with the outcome of their surgery. However, it is unknown how overground walking kinematics and kinetics might differ in the dissatisfied versus satisfied patients following TKR surgery. This study compared the lower-extremity walking kinematics and kinetics of patients dissatisfied with their TKR to that of satisfied patients and healthy controls. Thirty nine subjects completed walking trials, including nine dissatisfied and 15 satisfied TKR patients and 15 healthy controls. A 2 × 3 repeated -measures analysis of variance was used to assess differences between groups and limbs (P < .05). Dissatisfied persons showed significantly reduced loading-response and push-off peak vertical ground reaction forces, flexion range of motion, loading-response extension moments, and loading-response abduction moments compared to the controls. Peak loading-response and push-off vertical ground reaction forces and flexion range of motion were reduced in the replaced limb of dissatisfied patients compared with their nonreplaced limb. Push-off plantar flexion moments were reduced in the dissatisfied patients compared with the satisfied and healthy controls. Dissatisfied patients also reported increased knee joint pain and reduced preferred gait speed. Moreover, dissatisfied patients experienced mechanical limb asymmetries not present in those satisfied with their surgery result. Thus, patients dissatisfied with their total knee replacement outcome were found to be experiencing significant negative physiological changes.

Does saddle height influence knee frontal-plane biomechanics during stationary cycling?

INTRODUCTION

Cycling is a common modality for rehabilitation and exercise. However, there is a lack of information in the literature on the effects of saddle height adjustments on internal peak knee abduction moment, which is an important loading variable for the medial compartment of tibiofemoral joint for patients with knee osteoarthritis. The purpose of this study was to examine effects of saddle height on frontal-plane biomechanics of the knee during cycling.

METHODS

Fourteen recreational cyclists (age: 57.1 ± 6.37 years) performed 2-min bouts of cycling at three saddle heights of 40°, 30° and 20° knee extension angle at bottom crank position, at two workrates of 80 and 120 W. Three-dimensional kinematic, kinetic, and electromyography data were collected and analyzed using a 3 × 2 (height × workrate) analysis of variance (ANOVA).

RESULTS

There were no changes in internal knee abduction moment across saddle heights. Increases in saddle height from 40° to both 30° and 20° reduced the knee extension moment (d = 0.3 and 0.4, respectively, P = 0.012). Increases in workrate increased both knee abduction and extension moments (η²_p = 0.75 and 0.88, respectively, P < 0.001 for both).

CONCLUSIONS

Increased knee extension moment with decreased saddle height is likely to indicate increased knee joint load.

Validation of Garmin Fenix 3 HR Fitness Tracker Biomechanics and Metabolics (VO2max)

The purpose of this study was to determine the validity of the Garmin fēnix® 3 HR fitness tracker. Methods: A total of 34 healthy recreational runners participated in biomechanical or metabolic testing. Biomechanics participants completed three running conditions (flat, incline, and decline) at a self-selected running pace, on an instrumented treadmill while running biomechanics were tracked using a motion capture system. Variables extracted were compared with data collected by the Garmin fēnix 3 HR (worn on the wrist) that was paired with a chest heart rate monitor and a Garmin Foot Pod (worn on the shoe). Metabolic testing involved two separate tests; a graded exercise test to exhaustion utilizing a metabolic cart and treadmill, and a 15-min submaximal outdoor track session while wearing the Garmin. 2 × 3 analysis of variances with post hoc t tests, mean absolute percentage errors, Pearson’s correlation (R), and a t test were used to determine validity. Results: The fēnix kinematics had a mean absolute percentage errors of 9.44%, 0.21%, 26.38%, and 5.77% for stride length, run cadence, vertical oscillation, and ground contact time, respectively. The fēnix overestimated (p < .05) VO2max with a mean absolute percentage error of 8.05% and an R value of .917. Conclusion: The Garmin fēnix 3 HR appears to produce a valid measure of run cadence and ground contact time during running, while it overestimated vertical oscillation in every condition (p < .05) and should be used with caution when determining stride length. The fēnix appears to produce a valid VO2max estimate and may be used when more accurate methods are not available.

Knee joint biomechanics of patients with unilateral total knee arthroplasty during stationary cycling

Stationary cycling is typically recommended following total knee arthroplasty (TKA) operations. However, knee joint biomechanics during cycling remains mostly unknown for TKA patients. Biomechanical differences between the replaced and non-replaced limb may inform applications of cycling in TKA rehabilitation. The purpose of this study was to examine the knee joint biomechanics of TKA patients during stationary cycling. Fifteen TKA participants cycled at 80 revolutions per minute and workrates of 80 W and 100 W while kinematics (240 Hz) and pedal reaction forces using a pair of instrumented pedals (1200 Hz) were collected. A 2x2 (limb × workrate) repeated measures ANOVA was run with an alpha of 0.05. Peak knee extension moment (KEM, p = 0.034) and vertical pedal reaction force (p = 0.038) were significantly reduced in the replaced limbs compared to non-replaced limbs by 21.3% and 5.3%, respectively. Peak KEM did not change for TKA patients with the increased workrate (p = 0.750). However, both peak hip extension moment (p = 0.009) and ankle plantarflexion moment (p = 0.017) increased due to increased workrate. Patients following TKA showed similar decreases in peak KEM and vertical pedal reaction force in their replaced compared to non-replaced limbs, as previously seen in gait. Patients of TKA may rely on their hip and ankle extensors to increases in workrate. Increasing intensity by 20 W did not exacerbate any inter-limb differences for peak KEM and vertical PRF.

Increased knee loading in stair ambulation in patients dissatisfied with their total knee replacement

BACKGROUND

Total knee replacement patients have shown reductions in knee flexion range of motion, knee extensor moments, and gait speed during stair ascent and stair descent. However, it is unknown how patients dissatisfied with their total knee replacement differ from those who are satisfied during more difficult activities such as stair negotiation. Therefore, the purpose of this study was to compare knee biomechanics of patients who are dissatisfied with their joint replacement to those who are satisfied and healthy participants during stair negotiation.

METHODS

Nine dissatisfied, fifteen satisfied patients and fifteen healthy participants participated, completing stair ascent and descent trials on an instrumented staircase. A 2 × 3 ANOVA was used to analyze biomechanical differences between groups and limbs during both activities.

FINDINGS

The dissatisfied group showed reduced 2nd peak vertical GRF (P ≤ 0.0040) and loading-response knee extension moments (P ≤ 0.0041) in their operated limb compared to their non-operated limb and to satisfied and healthy groups during stair ascent. First peak vertical GRF (P < 0.0088) and both loading-response (P < 0.0117) and push-off abduction moments (P < 0.0028) showed reduced values in operated limbs compared to non-operated limbs for all groups. During stair descent, the dissatisfied group showed reduced loading-response and push-off knee extension moments (P ≤ 0.006) in their operated limb compared to their non-operated limb and the healthy group. The loading-response knee extension (P < 0.0379) and abduction moments (P ≤ 0.0048) were also reduced in the dissatisfied group compared to the satisfied group.

INTERPRETATION

Patients who were dissatisfied showed asymmetrical loading of the knees in conjunction, which may have contributed to their dissatisfaction.