Adaptations during the stance phase of gait for simulated flexion contractures at the knee

Outcomes of double-incision posterior knee release for severe knee flexion contracture

Many surgical solutions for knee flexiondeformity in the pediatric population alter the anatomical bony alignment in the distal femur. Posterior knee capsule release has been presented as an alternative surgical procedurethat maintains the anatomical shape of relevant bones while solving the issue of knee flexion contracture. The aim of this study is to assess the results of a double-incision posteriorknee capsulotomy release performed on pediatric patients with neuromuscular or congenital severe knee flexion deformity. Thirty cases (24 patients, mean age 7.4 years) of severe knee flexion contractures were retrospectively analyzed in a cohort of varying underlying conditions (including spina bifida, muscular dystrophy, cerebral palsy, sclerodermia, and congenital patellar dislocations). Posterior knee release was performed through medial and lateral short incisions with subsequent serial casting. Range and pace of correction as well as the complication rate were recorded. Follow-up information (>1 year) included functionality (FMS scale) and pain (Kujala/Knee Injury Osteoarthritis Score [KOOS]) scales. Significant correction in the knee position was achieved in all analyzed knees (from mean 40.2° to 0.7°; P < 0.01). Twenty-nine out of 30 cases achieved correction by 7 days postoperatively (average number of casts: 1.93 ± 1.05). Overall complication rate in the analyzed cohort reached 6.7% (2/30 cases; double metaphyseal fracture and arthrofibrosis). At follow-up (22.3 months on average), functional ambulation and pain parameters improved drastically, with no further complications observed. Double-incision posterior knee release is an effective method of knee contracture release, which does not affect the axial alignment of the distal femoral bone. Thus, posterior knee release should be considered as potential alternatives to osteotomies and eight-plate corrections, which are currently the basic methods of knee contracture treatment.

Radiographic Measures for the Assessment of Frontal and Sagittal Knee Alignments and the Associated Normality Values: A Meta-Analysis

Objective

The purpose of this literature review was to identify knee alignment assessment methods using radiography in the sagittal and frontal planes and to identify normality values for classifying knee alignment using these methods.

Methods

A systematic review with a meta-analysis was conducted. The eligibility criterion was studies that performed radiographic examinations to assess the knee alignment of adults without a history of hip or knee prosthesis surgery. The methodological qualities of the included studies were assessed using the QUADAS-2 tool. A meta-analysis was performed to measure the normality values of knee alignment in the frontal plane.

Results

The hip-knee-ankle (HKA) angle was the measure most frequently used to assess knee alignment. Only a meta-analysis of HKA normality values was possible. Thereby, we found normality values of the HKA angle for the overall population, men, and women. The normality values of knee alignment for healthy adults that were found in this study were as follows: overall sample (male and female patients) HKA angle = -0.2° (-2.8° to 2.41°), male patient HKA angle = 0.77° (-2.91° to 7.94°), and female patient HKA angle = -0.67° (-5.32° to 3.98°).

Conclusion

This review identified the most common methods and expected values for knee alignment assessment methods using radiography in the sagittal and frontal planes. We suggest HKA angles ranging from -3° to 3° as the cutoff for classifying knee alignment in the frontal plane, in accordance with the normality limits found in the meta-analysis.

Effects of orthoses on muscle activity and synergy during gait

An orthosis is often used in rehabilitation to improve kinetic and kinematic parameters during gait. However, whether changes in neural control depend on wearing an orthosis during gait is unclear. We measured the muscle activity and synergy of the lower limb muscles without orthosis and with two types of orthoses: ankle-foot orthosis (AFO) and knee-ankle-foot orthosis (KAFO). Muscle activity during gait was measured in 15 healthy adults, and muscle synergies were extracted using non-negative matrix factorization. The results revealed that some muscle activities were significantly different among the three conditions. Post-hoc analysis indicated differences between each condition. Knee extensor muscle activity related to the loading response was significantly increased by wearing the AFO. In the KAFO condition, hip abductor muscle activity related to weight bearing was significantly decreased, and ankle dorsiflexor muscle activity was increased to secure clearance during the swing phase. However, the number of muscle synergies and complexity of muscle synergy did not significantly change among these conditions. However, along with changes in muscle activity, the activation pattern and weightings of muscle synergies tended to change with the use of orthoses. Each muscle activity was changed by wearing the orthosis; however, the immediate mechanical constraint did not change the framework of muscle synergy.

Effect of Unilateral Knee Extension Restriction on the Lumbar Region during Gait

Unilateral knee extension restriction might change trunk alignment and increase mechanical load on the lumbar region during walking. We aimed to clarify lumbar region mechanical load during walking with restricted knee extension using a musculoskeletal model simulation. Seventeen healthy adult males were enrolled in this study. Participants walked 10 m at a comfortable velocity with and without restricted right knee extension of 15° and 30° using a knee brace. L4-5 joint moment, joint reaction force, and muscle forces around the lumbar region during walking were calculated for each condition. Peaks of kinetic data were compared among three gait conditions during 0%-30% and 50%-80% of the right gait cycle. Lumbar extension moment at early stance of the bilateral lower limbs was significantly increased in the 30° restricted condition (p ≤ 0.021). Muscle force of the multifidus showed peaks at stance phase of the contralateral side during walking, and the erector spinae showed force peaks at early stance of the bilateral lower limb. Muscle force of the multifidus and erector spinae increased with increasing degree of knee flexion (p ≤ 0.010), with a large effect size (η ² = 0.273-0.486). The joint force acting on L4-5 showed two peaks at early stance of the bilateral lower limbs during the walking cycle. The anterior and vertical joint force on L4-5 increased by 14.2%-36.5% and 10.0%-23.0% in walking with restricted knee extension, respectively (p ≤ 0.010), with a large effect size (η ² = 0.149-0.425). Restricted knee joint extension changed trunk alignment and increased the muscle force and the vertical and anterior joint force on the L4-5 joint during walking; this tendency became more obvious with increased restriction angle. Our results provide important information for therapists engaged in the rehabilitation of patients with knee contracture.

Results of revision knee replacement for patients with isolated fixed flexion deformity after primary or revision knee replacement

BACKGROUND

Postoperative fixed flexion deformity is a known complication of knee replacement surgery. We present our results of revision surgery for treatment of isolated fixed flexion deformity after knee replacement.

METHODS

32 patients had revision knee replacement for fixed flexion deformity and were included in this retrospective study. Minimum follow up period was 28 months.

RESULTS

Two different surgical interventions had been done in these patients. Group 1 (15 patients) had revision of the femoral component, posterior capsular release and tibial component was not revised. Group 2 (18 Patients) had revision of both femoral and tibial components. One patient was included in both groups as she had both interventions. The extent of preoperative flexion deformity in group 1 was from 15 to 40 deg (mean 20.6 deg). Postoperative range of extension was 0 to 20 deg (mean 8.2 deg). In group 2, preoperative flexion deformity was 10 to 25 deg (mean 16.9 deg) and postoperative flexion deformity was 0 to 20 deg (mean 4.2 deg). The difference in improvement between the two groups was not statistically significant on Mann Whitney U test (two tailed p value 0.181) for non normal distribution. Improvement in Oxford knee score following surgery was only 1 point in both groups.

CONCLUSION

Revision for isolated fixed flexion deformity leads to improvement in range of extension, but improvement in clinical score is marginal. The choice of preservation or revision of the tibial component did not make a significant difference to the outcome.

Gait Phase Estimation Based on User–Walker Interaction Force

Smart walkers have been developed for assistance and rehabilitation of elderly people and patients with physical health conditions. A force sensor mounted under the handle is widely used in smart walkers to establish a human–machine interface. The interaction force can be used to control the walker and estimate gait parameters using methods such as the Kalman filter for real-time estimation. However, the estimation performance decreases when the peaks of the interaction force are not captured. To improve the stability and accuracy of gait parameter estimation, we propose an online estimation method to continuously estimate the gait phase and cadence. A multiple model switching mechanism is introduced to improve the estimation performance when gait is asymmetric, and an adaptive rule is proposed to improve the estimation robustness and accuracy. Simulations and experiments demonstrate the effectiveness and accuracy of the proposed gait parameter estimation method. Here, the average estimation error for the gait phase is 0.691 rad when the gait is symmetric and 0.722 rad when it is asymmetric.

Modular reorganization of gait in chronic but not in artificial knee joint constraint

It is currently unknown if modular reorganization does occur if not the central nervous system, but the musculoskeletal system is affected. The aims of this study were to investigate 1) the effects of an artificial knee joint constraint on the modular organization of gait in healthy subjects; and 2) the differences in modular organization between healthy subjects with an artificial knee joint constraint and people with a similar but chronic knee joint constraint. Eleven healthy subjects and eight people with a chronic knee joint constraint walked overground at 1 m/s. The healthy subjects also walked with a constraint limiting knee joint movement to 20°. The total variance accounted (tVAF) for one to four synergies and modular organization were assessed using surface electromyography from 11 leg muscles. The distribution of number of synergies were not significantly different between groups. The tVAF and the motor modules were not significantly affected by the artificial knee constraint. A higher tVAF for one and two synergies, as well as merging of motor modules were observed in the chronic knee constraint group. We conclude that in the short-term a knee constraint does not affect the modular organization of gait, but in the long-term a knee constraint results in modular reorganization. These results indicate that merging of motor modules may also occur when changes in the mechanics of the musculoskeletal system is the primary cause of the motor impairment.NEW & NOTEWORTHY It is currently unknown if modular reorganization does occur if not the central nervous system, but the musculoskeletal system is affected. This study showed that in the short-term a knee constraint does not affect the modular organization of gait, but in the long-term a knee constraint results in modular reorganization. These results indicate that modular reorganization may also occur when changes in the mechanics of the musculoskeletal system is the primary cause of the motor impairment.

Kinematics can help to discriminate the implication of iliopsoas, hamstring and gastrocnemius contractures to a knee flexion gait pattern

BACKGROUND

Excessive Knee Flexion Gait Pattern (KFGP) is a common gait deviation in many pathological conditions. The contractures of the muscles that have been identified as being responsible of KFGP are: iliopsoas, hamstring and gastrocnemius.

RESEARCH QUESTION

How do isolated contractures of the iliopsoas, hamstrings and gastrocnemius impact knee flexion during gait?

METHODS

Three levels of contracture (mild, moderate and severe) were simulated bilaterally using an exoskeleton on 10 healthy participants for iliopsoas, hamstring and gastrocnemius muscles. A gait analysis session was performed to evaluate the joint kinematics according to the different simulated contractures. Thirty one parameters were chosen to analyze the kinematics of the thorax, pelvis, hip, knee and ankle. A principal component analysis (PCA) was used to determine the kinematic parameters influenced by contractures.

RESULTS

In addition to a permanent knee flexion observed for the three muscles with contracture: the contracture of the iliopsoas induces a large hip flexion with pronounced anterior pelvis tilt; the contracture of the hamstrings induces an ankle dorsiflexion during the support phase with a posterior pelvis tilt; the contracture of the gastrocnemius induces an absence of first and second rocker of the ankle with a slight flexion of hip and a slight anterior pelvis tilt.

SIGNIFICANCE

These results support the identification of the muscles responsible for a KFGP. A better knowledge of the interactions between contractures and associated joint kinematics of the same and adjacent joints will support the interpretation of gait analyses by more precisely and faster targeting the concerned muscle.

Revision surgery for failed anterior cruciate ligament reconstruction with extension deficiency

BACKGROUND

Some patients with recurrent symptomatic instability after primary anterior cruciate ligament (ACL) reconstruction have an extension deficiency (ED). This study (a) compared preoperative clinical conditions between the ED and non-ED groups undergoing revision ACL reconstruction, (b) documented clinical and arthroscopic findings in ACL-reconstructed patients with reinstability and ED, and (c) determined whether the ED could be resolved and whether the clinical results of revision surgery differed between the ED and non-ED groups.

METHODS

This study included 58 patients who underwent revision ACL reconstruction. Patients were divided into the ED and non-ED groups. Preoperatively, the demographics and clinical conditions of the two groups were compared. Intraoperatively, the pathological structures that related to ED were documented. After surgery, the degree of postoperative ED and functional outcomes were compared between the two groups at 2-year follow-up.

RESULTS

The International Knee Documentation Committee subjective score and SF-36 physical component summary scores were worse in the ED group than the non-ED group preoperatively (54 vs 48 [P = 0.014]; 42 vs 39 [P = 0.031], respectively). Intraoperatively, the ED group showed significantly more frequent graft malposition (50% vs 5%), anvil osteophytes (44% vs 0%), and scarring around posterior intercondylar notch (100% vs 0%). However, there was no difference in the degree of postoperative ED and functional outcome between the two groups at follow-up.

CONCLUSIONS

ED in patients with recurrent instability after primary ACL reconstruction could be treated with good clinical result by addressing the pathological conditions causing ED in addition to ACL re-reconstruction.

Walking with an induced unilateral knee extension restriction affects lower but not upper body biomechanics in healthy adults

BACKGROUND

Unilateral knee flexion contractures (KFC) are frequently seen in orthopedic rehabilitation and often interfere with the normal gait pattern, resulting in passive and/or active secondary deviations. In order to prevent KFC-related complications such as patellofemoral pain or the knee spine syndrome, a comprehensive understanding of such deviations is necessary.

RESEARCH QUESTION

How does an artificially induced unilateral KFC affect whole body biomechanics in young healthy adults during gait?

METHODS

Twenty-four healthy young adults (females/males: 13/11; mean age: 27.3 ± 3.8 years) were included in this cross-sectional study. Using an 8-camera optical motion capture system and two embedded force plates, three-dimensional lower extremity, pelvis and trunk kinematics as well as lower extremity joint moments were derived during normal walking and walking with unilateral KFCs by means of a lightweight knee brace locked at 30° and 60° of flexion. Data were analyzed using one-dimensional statistical parametric mapping, allowing explorative group comparisons of continuous data rather than pre-defined discrete parameters.

RESULTS

On the braced side, increased hip flexion (p < 0.001, 1-100 % of gait cycle [%GC]), knee flexion (p < 0.001, 1-72 and 82-100 %GC) and ankle dorsiflexion angles (p < 0.001, 1-100 %GC) as well as external knee flexion moments (p < 0.001, 1-98 % of stance phase [%StPh]) and decreased ankle dorsiflexion (p < 0.001, 74-94 %StPh), hip flexion and hip adduction moments (p < 0.001, 1-32 %StPh and p < 0.001, 71-92 %StPh, respectively) were observed. The unbraced side showed similar but less pronounced deviations. Pelvis and upper body kinematics were not altered, suggesting that the lower limbs fully compensate for KFCs of less than 30°.

SIGNIFICANCE

Asymmetric limb loading and considerable increases in external knee flexion moments might increase the risk for adverse effects of lower extremity joints in the long-term. It seems therefore important to treat KFCs as early as possible and to implement preventive strategies to avoid possible complications.

Relief of knee flexion contracture and gait improvement following adaptive training for an assist device in a transtibial amputee: A case study

BACKGROUND

Management of a knee contracture is important for regaining gait ability in transtibial amputees. However, there has been little study of prosthesis training for enhancing mobility and improving range of motion in cases of restricted knee extension.

OBJECTIVE

This study aimed to evaluate the effects of adaptive training for an assist device (ATAD) for a transtibial amputee with a knee flexion contracture (KFC). A male transtibial amputee with KFC performed 4 months of ATAD with a multidisciplinary team. During the ATAD, the passive range of motion (PROM) in the knee, amputee mobility predictor (AMP) assessment, center of pressure (COP) on a force plate-equipped treadmill, gait features determined by three-dimensional motion analysis, and Short-Form 36 Item Health Survey (SF-36) scores were evaluated.

RESULTS

Following ATAD, PROM showed immediate improvement (135.6 ± 2.4° at baseline, 142.5 ± 1.7° at Step 1, 152.1 ± 1.8° at Step 2, 165.8 ± 1.9° at Step 3, and 166.0 ± 1.4° at Step 4); this was followed by an enhanced COP. Gradually, gait features also improved. Additionally, the AMP score (5 at baseline to 29 at Step 4) and K-level (K0 at baseline to K3 at Step 4) increased after ATAD. Along with these improvements, the SF-36 score also improved.

CONCLUSIONS

ATAD could be beneficial for transtibial amputees by relieving knee contractures and improving gait.

Factors affecting one-leg standing time in patients with end-stage knee osteoarthritis and the age-related recovery process following total knee arthroplasty

Background

The aims of the present study were to investigate the factors affecting one-leg standing (OLS) time in patients with end-stage knee osteoarthritis (OA) and to clarify the age-related recovery process following total knee arthroplasty (TKA) in the early postoperative period.

Methods

A total of 80 knees of 40 patients with knee OA were enrolled. They were asked to perform relaxed standing on one leg for as long as possible. First, OLS time was measured. Second, age, body mass index, knee flexion angle during (KFA) OLS, femorotibial angle (FTA) during OLS, and a visual analogue scale (VAS) for pain were evaluated. Multiple regression analysis was done to identify the factors affecting OLS time. In addition, the recovery process was compared between older and younger patients after TKA.

Results

A larger KFA during OLS, older age, and larger FTA were significantly associated with shorter OLS time. After TKA, postoperative OLS time in older patients did not improve significantly by postoperative day 20, while the time in younger patients improved significantly from postoperative day 19.

Conclusions

Even if subjective knee pain and KFA during OLS improved, longer rehabilitation was required to improve OLS time in older patients in the early postoperative period.

Feasibility and reliability of using an exoskeleton to emulate muscle contractures during walking

Contracture is a permanent shortening of the muscle-tendon-ligament complex that limits joint mobility. Contracture is involved in many diseases (cerebral palsy, stroke, etc.) and can impair walking and other activities of daily living. The purpose of this study was to quantify the reliability of an exoskeleton designed to emulate lower limb muscle contractures unilaterally and bilaterally during walking. An exoskeleton was built according to the following design criteria: adjustable to different morphologies; respect of the principal lines of muscular actions; placement of reflective markers on anatomical landmarks; and the ability to replicate the contractures of eight muscles of the lower limb unilaterally and bilaterally (psoas, rectus femoris, hamstring, hip adductors, gastrocnemius, soleus, tibialis posterior, and peroneus). Sixteen combinations of contractures were emulated on the unilateral and bilateral muscles of nine healthy participants. Two sessions of gait analysis were performed at weekly intervals to assess the reliability of the emulated contractures. Discrete variables were extracted from the kinematics to analyse the reliability. The exoskeleton did not affect normal walking when contractures were not emulated. Kinematic reliability varied from poor to excellent depending on the targeted muscle. Reliability was good for the bilateral and unilateral gastrocnemius, soleus, and tibialis posterior as well as the bilateral hamstring and unilateral hip adductors. The exoskeleton can be used to replicate contracture on healthy participants. The exoskeleton will allow us to differentiate primary and compensatory effects of muscle contractures on gait kinematics.

Spontaneous Improvement of Compensatory Knee Flexion After Surgical Correction of Mismatch Between Pelvic Incidence and Lumbar Lordosis

STUDY DESIGN

A retrospective study.

OBJECTIVE

The aim of this study was to investigate the correlation between pelvic incidence (PI) and lumbar lordosis (LL) mismatch and knee flexion during standing in patients with lumbar degenerative diseases and to examine the effects of surgical correction of the PI-LL mismatch on knee flexion.

SUMMARY OF BACKGROUND DATA

Only several studies focused on knee flexion as a compensatory mechanism of the PI-LL mismatch. Little information is currently available on the effects of lumbar correction on knee flexion in patients with the PI-LL mismatch.

METHODS

A group of patients with lumbar degenerative diseases were divided into PI-LL match group (PI-LL ≤ 10°) and PI-LL mismatch group (PI-LL > 10°). A series of radiographic parameters and knee flexion angle (KFA) were compared between the two groups. The PI-LL mismatch group was further subdivided into operative and nonoperative group. The changes in KFA with PI-LL were examined.

RESULTS

The PI-LL mismatch group exhibited significantly greater sagittal vertical axis (SVA), pelvic tilt (PT) and KFA, and smaller LL, thoracic kyphosis (TK), and sacral slope than the PI-LL match group. PI-LL, LL, PI, SVA, and PT were significantly correlated with KFA in the PI-LL mismatch group. From baseline to 6-month follow-up, all variables were significantly different in the operative group with the exception of PI, although there was no significant difference in any variable in the nonoperative group. The magnitude of surgical correction in the PI-LL mismatch was significantly correlated with the degree of spontaneous changes in KFA, PT, and TK.

CONCLUSION

The PI-LL mismatch would contribute to compensatory knee flexion during standing in patients with lumbar degenerative disease. Surgical correction of the PI-LL mismatch could lead to a spontaneous improvement of compensatory knee flexion. The degree of improvement in knee flexion depends in part on the amount of correction in the PI-LL mismatch.

LEVEL OF EVIDENCE

3.

Effects of contracture on gait kinematics: A systematic review

BACKGROUND

Contractures of a major joint in the lower limbs may impair human walking in addition to other daily living activities. A contracture is defined as the inability of a joint to perform the full range of motion and excessive resistance during passive mobilization of the joint. Few studies have reported methods describing how to evaluate contractures. Understanding the association among all of these studies seems essential to improve patient management. Therefore, we conducted a systematic review on this topic to elucidate the influence of contractures on gait kinematics.

METHODS

An electronic search in the literature will be conducted. Studies were screened by title and abstract and full texts were evaluated secondarily for definitive inclusion. The quality of the included studies was assessed independently by the two review authors with the Modified Quality Assessment Checklist. The included studies were separated into three categories: pathological contracture versus healthy controls (descriptive), simulated contracture versus healthy controls (experimental), and pre- and post-kinematics after surgical muscle lengthening (surgery).

FINDINGS

From a total of 4402 references, 112 original articles were selected, and 28 studies were identified in this systematic review. No significant difference between raters was observed on the total score of the Modified Quality Assessment Checklist.

INTERPRETATION

Contractures influence walking depending on the location (muscle) and the contracture level (muscle-tendon length). After giving a definition of contracture, this review identified some contracture alterations, such as plantarflexion, knee flexion and hip flexion contractures, with a kinematic description and presented possible different compensations.

Custom Knee Device for Knee Contractures After Internal Femoral Lengthening

The development of knee flexion contractures is among the most common problems and complications associated with lengthening the femur with an internal device or external fixator. Conservative treatment strategies include physical therapy, serial casting, and low-load prolonged stretching with commercially available splinting systems. The authors developed an individually molded, low-cost custom knee device with polyester synthetic conformable casting material to treat knee flexion contractures. The goal of this study was to evaluate the results of treatment with a custom knee device and specialized physical therapy in patients who had knee flexion contracture during femoral lengthening with an intramedullary lengthening femoral nail. This retrospective study included 23 patients (27 limbs) who underwent femoral lengthening with an internal device for the treatment of limb length discrepancy. All patients had a knee flexion contracture raging from 10° to 90° during the lengthening process and were treated with a custom knee device and specialized physical therapy. The average flexion contracture before treatment was 36°. The mean amount of lengthening was 5.4 cm. After an average of 3.8 weeks of use of the custom knee device, only 2 of 27 limbs (7.5%) had not achieved complete resolution of the flexion contracture. The average final extension was 1.4°. Only 7 of 27 limbs (26%) required additional soft tissue release. The custom knee device is an inexpensive and effective method for treating knee flexion contracture after lengthening with an internal device.

The effect of knee flexion contracture following total knee arthroplasty on the energy cost of walking

This study evaluated the energy cost of walking (Cw) with knee flexion contractures (FC) simulated with a knee brace, in total knee arthroplasty (TKA) recipients (n=16) and normal controls (n=15), and compared it to baseline (no brace). There was no significant difference in Cw between the groups at baseline but TKA recipients walked slower (P=0.048) and with greater knee flexion in this condition (P=0.003). Simulated FC significantly increased Cw in both groups (TKA P=0.020, control P=0.002) and this occurred when FC exceeded 20° in the TKA group and 15° in the controls. Reported perceived exertion was only significantly increased by FC in the control group (control P<0.001, TKA P=0.058). Simulated knee FCs less than 20° do not increase Cw or perceived exertion in TKA recipients.

Manipulation under anaesthesia versus low stretch device in poor range of motion after TKA

PURPOSE

The purpose of this study was to evaluate the effectiveness of two frequently used non-operative treatment techniques for a stiff knee after total knee arthroplasty.

METHODS

Sixty-four patients with a stiff knee after total knee arthroplasty (TKA) were randomized into a manipulation under anaesthesia group, or a low load stretch (stretch) group. The patients were followed up for 6 weeks and were evaluated for maximum flexion and extension, range of motion (ROM), pain, stiffness and function.

RESULTS

Both groups showed a significant increase in knee flexion in this study. Only the stretch group showed a significant increase in extension ROM. In both groups, a significant increase in Western Ontario and McMaster Universities was observed. No significant difference was observed between both groups for the flexion or extension ROM, or for any of the pain, function or stiffness scores during this study.

CONCLUSIONS

The results of this study showed that the stretch technique had equal or superior results concerning ROM and function compared to manipulation under anaesthesia. The stretch technique achieved this without requiring the patient to undergo in-hospital treatment or anaesthesia, limiting the costs and the risks for complications. The results of this study showed that stretching is a valuable tool for treating joint contractures of the knee. Therefore, the use of this stretching technique may be an excellent first choice of treatment modality in patients with slow progress of knee flexion or persistent knee stiffness following TKA, prior to manipulation under anaesthesia or lysis of adhesions.

Effect of Anterior Tibiofemoral Glides on Knee Extension during Gait in Patients with Decreased Range of Motion after Anterior Cruciate Ligament Reconstruction

PURPOSE

The purpose of this preliminary investigation was to evaluate the effect of anterior tibiofemoral glides on maximal knee extension and selected spatiotemporal characteristics during gait in patients with knee extension deficits after anterior cruciate ligament (ACL) reconstruction.

METHODS

Twelve patients with knee-extension deficits after recent ACL reconstructions underwent quantitative gait analyses immediately before and after 10 minutes of repeated anterior tibiofemoral glides on the operative limb, and again after a 10-minute seated rest period.

RESULTS

Maximum knee extension during stance phase of the operative limb significantly increased immediately after the treatment (mean increase: 2.0°±4.1°, 95% CI: 0.6°-3.3°). Maximum knee extension decreased after the 10-minute rest period (mean decrease: 0.9°±1.8°, 95% CI: -0.1°-1.8°), although the decrease was not statistically significant. Small increases in operative limb step length, stride length, and gait speed were observed after the rest period compared to baseline values only.

CONCLUSIONS

A single session of anterior tibiofemoral glides increases maximal knee extension during the stance phase of gait in patients with knee-extension deficits. Increases in knee extension are small and short-lived, however, suggesting that continued activity is required to maintain the observed improvements.

Surface electromyography does not accurately reflect rectus femoris activity during gait: impact of speed and crouch on vasti-to-rectus crosstalk

Surface EMG (sEMG) is routinely used in gait analysis laboratories to record rectus femoris (RF) activity during gait. This is despite the fact that the literature has suggested sEMG may be inaccurate for RF monitoring secondary to its susceptibility to crosstalk from the neighboring vasti. If true, one might expect this error to be exacerbated by crouch gait when vasti demand is elevated. The purpose of this study was to investigate the impact of vasti crosstalk on RF sEMG across a variety of speed (four) and crouch (four) combinations. A group of 20 able-bodied adults were studied walking in 16 different combinations of speed and crouch while computerized gait analysis and EMG data were collected. RF EMG activity was monitored using both surface and fine wire electrodes simultaneously. Results showed that sEMG is affected by vasti crosstalk during substantial portions of both stance and swing. At the two slowest speeds tested, RF was not active at any point during the gait cycle, though sEMG suggested RF activity during some to all of stance phase. Despite sEMG indicating otherwise, true RF did not occur during loading response in any of the 16 conditions tested. During crouch at the two fastest speeds, a burst of true RF activity occurred during a short period of single limb stance, though sEMG incorrectly reflected RF activity throughout stance. Vasti-to-rectus crosstalk also occurred regularly during terminal swing. Surface EMG incorrectly suggests RF activity during portions of both stance and swing secondary to vasti crosstalk. This may lead to interpretation errors which could affect clinical recommendations.

Evaluation of a custom device for the treatment of flexion contractures after total knee arthroplasty

Knee flexion contractures can severely impair function after total knee arthroplasties. We evaluated the use of a custom-molded knee device to treat 47 patients who had knee flexion contractures (mean, 22 degrees; range, 10 degrees-40 degrees) after primary or revision total knee arthroplasties and who had failed conventional therapeutic methods. The device was used for 30 to 45 minutes per session two to three times per day in conjunction with standard physical therapy modalities two to three times per week. Twenty-seven of 29 patients who underwent primary total knee arthroplasty and 13 of 18 patients who underwent revisions achieved full extension after a mean treatment time of 9 weeks (range, 6-16 weeks). Full knee extension was maintained at a minimum followup of 18 months (mean, 24 months; range, 18-36 months). The mean Knee Society knee and functional scores improved from 50 points and 34 points to 91 points and 89 points, respectively. This protocol had comparable rates of improvement in knee extension with less treatment time when compared with other nonoperative treatments reported in the literature. The custom knee device may be a useful adjunct to a physical therapy regimen for knee flexion contractures after total knee arthroplasty.

LEVEL OF EVIDENCE

Level IV, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Recovery in functional non-copers following anterior cruciate ligament rupture as detected by gait kinematics

OBJECTIVES

To evaluate if gait compensation strategies for selected kinematic variables can be identified in anterior cruciate ligament (ACL) deficient non-copers using two-dimensional (2D) clinical gait analysis.

DESIGN

Prospective observational design, repeated measures.

SETTING

University hospital, out-patients department.

PATIENTS

Sixty-three patients that attended the acute knee screening service were diagnosed with an acute ACL rupture and consented to participate. A sub-set of 15 copers/adapters and 13 non-copers were eligible for final analysis because they were contactable for sub-classification and had gait analysis at 1 and 4 months post-injury.

MAIN OUTCOME MEASURES

2D video gait analysis for sagittal plane hip, knee and ankle kinematics and time-distance variables.

RESULTS

At 4 months post-injury non-copers demonstrated significantly less recovery of knee angle (F((1,1))=5.79, p<0.024), hip displacement angle (F((1,1))=4.89, p<0.036), step length (F((1,1)) =6.80, p=0.015), cadence (F((1,1))=5.85, p=0.023) and velocity (F((1,1))=10.89, p=0.003), compared to copers/adapters. Also non-copers demonstrated altered correlations between gait parameters.

CONCLUSION

At 4 months post-injury non-copers had an inferior gait performance compared to copers/adapters for kinematics and time-distance variables. 2D clinical kinematic gait analysis, particularly of the hip and knee can inform early rehabilitation techniques and monitor recovery.

When does postoperative standing function after total knee arthroplasty improve beyond preoperative level of function?

The purpose of the current study was to investigate inpatient recovery process during relaxed standing, and to clarify the question of when postoperative standing function would improve beyond preoperative level of function following total knee arthroplasty (TKA). Thirty patients with bilateral knee osteoarthritis, averaged 75 years old, participated. Subjects underwent unilateral TKA. Evaluations were divided into two categories; subjective and objective components. Subjective component was based on pain level (Visual Analog Scale: 100 mm), and objective component consisted of vertical knee force (%BW) and knee flexion angle (degrees) during relaxed standing. Data evaluations were done pre- and post-operatively. Preoperative pain score was 69.1. After TKA, pain level became maximum (89.9) and significantly larger on postoperative day 3. Thereafter, pain gradually decreased, and it (60.4) was significantly smaller on postoperative day 8 than preoperative score. Preoperative vertical knee force was 43.5%BW. After TKA, it became minimum (32.8) on postoperative day 3. Thereafter, knee force gradually increased, and it (44.1) was significantly larger on postoperative day 17. Preoperative knee flexion angle was 15.6 degrees . After TKA, knee flexion angle during standing became maximum (20.0) on postoperative day 4. Thereafter, subjects could gradually extend the knee, and on postoperative day 16, it (14.3 degrees ) was smaller. From our results, subjective pain was significantly reduced from postoperative day 8, and objective knee condition, including vertical knee force on TKA side and knee flexion angle on TKA side during standing, significantly became better from postoperative day 17 and 16, respectively.

Knee flexion contracture will lead to mechanical overload in both limbs: a simulation study using gait analysis

The purpose of the current study was to investigate the effect of knee flexion contracture on the knee mechanics both in affected and contralateral limbs during gait. Ten healthy old women, with mean age of 62 years, participated. Unilateral knee flexion contractures of 0, 15, and 30 degrees were simulated with a knee brace. All subjects performed walking trials with or without the simulation. Net knee extension moments, net knee adduction moments (%BW Ht), external knee forces (%BW), and maximum axial loading rate (%BW/s) at the knee were calculated both in contracture side and non-contracture side under different contracture conditions. Bilateral net knee extension moment gradually increased as the angle of contracture increased. The net knee extension moments in non-contracture limb were significantly larger with 15 and 30 degrees contracture than those without the contracture. Net knee adduction moment in non-contracture limb significantly increased with 15 and 30 degrees contracture. The knee shearing forces in contracture side and the knee compressive force in non-contracture side also significantly increased with 15 and 30 degrees simulation. As the flexion contracture became greater than 15 degrees , maximum axial loading rate also significantly increased in non-contracture side. From our results, the knee flexion contracture greater than 15 degrees led to mechanical overloads in both limbs. Correction of the contracture is clinically important to avoid any adverse effect.

A gait analysis of simulated knee flexion contracture to elucidate knee-spine syndrome

Knee flexion contracture influences the physiological movements in lower extremities and may cause the kinematic changes of the trunk. Our purpose was to investigate static and dynamic changes in trunk kinematics with simulated knee flexion contracture. Ten healthy females averaged 62 years participated in our study. Unilateral knee flexion contractures of 15 degrees and 30 degrees were simulated with a knee brace. Relaxed standing and level walking were measured at our laboratory using a motion analysis system which consisted of five cameras, a force plate, and thirteen retro-reflective markers. Three-dimensional trunk kinematics and vertical knee forces (% Body Weight) with the contractures were compared with those without the contracture. The 15 degrees contracture did not significantly change trunk kinematics. However, the 30 degrees contracture significantly changed the kinematics in each of the following planes. In the coronal plane, the trunk tilted to the contracture side in standing and walking. In the sagittal plane, posterior inclination of the pelvis in standing significantly increased. In addition, anterior inclination of the trunk and pelvis during walking significantly increased. In the axial plane, trunk rotation to the unaffected side significantly decreased during walking. The vertical knee force in the contracture limb decreased, being accompanied by the increase of the force in the unaffected limb during standing and walking. Results of our study suggest that knee flexion contracture significantly influences three-dimensional trunk kinematics during relaxed standing and level walking, and will lead to spinal imbalance. These facts may explain the onset of the "Knee-Spine Syndrome".

Physical Determinants, Emerging Concepts, and Training Approaches in Gait of Individuals with Spinal Cord Injury

The aim of this review is to examine the physical determinants for functional walking as well as the efficacy of gait rehabilitation after spinal cord injury (SCI) in humans. The results indicate several important physical determinants in gait. Examples are provided of different interventions that produce beneficial effects on outcome measures of gait such as gait speed, stride length, walking endurance, motor recovery, and gait quality. These findings need to be considered in current SCI rehabilitation practices, but the efficacy of certain interventions remains unclear. Well-designed clinical trials are needed to provide evidence of the role of physical determinants in the development of new concepts and principles in locomotor recovery after SCI. This review focuses on relevant literature, and informs rehabilitation specialists and basic scientists about the physical determinants and factors to consider for optimization of gait training in individuals with incomplete SCI.

Excision of heterotopic ossification from the knee: a functional outcome study

We retrospectively reviewed 17 consecutive patients with neurologic injuries (22 knees) who had excision of heterotopic ossification (22 knees, five bilateral) of the knees. Our primary research goal was to determine the change in range of motion at the knee after resection of heterotopic ossification in patients with neurologic injuries. Our secondary research goal was to determine the mobility gains measured regarding ambulatory and sitting functions for these patients. Diagnoses included traumatic brain injury (15 patients), anoxia (one patient), and spinal cord injury (one patient). The average age of the patients was 33 years (range, 19-51 years). Data were collected by an independent observer and included range of motion of the knee, ambulatory ability according to a five-level scale, and sitting ability according to a three-level scale. The average followup was 32 months. Range of motion improved by 65 degrees postoperatively. Extension improved from a preoperative mean of 16 degrees to a postoperative mean of 2 degrees . Flexion improved from a preoperative mean of 57 degrees to a postoperative mean of 107 degrees . Ambulatory and sitting function improved as a result of treatment. Surgical excision of heterotopic ossification of the knee is an effective procedure to increase joint mobility and function.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series-no, or historical control group). See the Guidelines for Authors for a complete description of levels of evidence.

Effects of wedged shoes and ankle-foot orthoses on standing balance and knee extension in children with cerebral palsy who crouch

PURPOSE

Effects of wedged shoes with solid ankle-foot orthoses (WAFOs) on standing balance (SB) were evaluated, as well as effects of AFOs alone on knee extension (KE) in children with cerebral palsy who crouch.

METHODS

Using a repeated-measures design, 11 children (four to 13 years old) were tested four times at two-week intervals. AFO intervention comprised the first four weeks and WAFO intervention the second four weeks. SB and KE were measured during three conditions at each visit: no orthoses (NO), AFO, and WAFO. Test-retest reliability and AFO effects on KE were examined after the first month. WAFO effects on SB were examined after the second month.

RESULTS

Intraclass correlation coefficients for KE were 0.89 (NO), 0.83 (AFO), and 0.81 (WAFO), and for SB, they were 0.98 (NO), 0.98 (AFO), and 0.97 (WAFO). Paired t tests for KE after AFO intervention were not significant. Restricted maximum likelihood estimations for SB were not significant. A post hoc power analysis of 68% suggested a type II error.

CONCLUSION

Further study is warranted to establish efficacy.