How accurate is partial weightbearing?

Audio-biofeedback versus the scale method for improving partial weight-bearing adherence in healthy older adults: a randomised trial

PURPOSE

To investigate how audio-biofeedback during the instruction of partial weight-bearing affected adherence, compared to traditional methods, in older adults; and to investigate the influence of individual characteristics.

METHODS

The primary outcome measure of this randomised controlled trial was the amount of load, measured as the ground reaction force, on the partial weight-bearing leg. The secondary outcome was the influence of individual characteristics on the amount of load. Included were healthy volunteers 60 years of age or older without gait impairment. Participants were randomly allocated to one of two groups; blinding was not possible. Partial weight-bearing of 20 kg was trained using crutches with audio-biofeedback (intervention group) or a bathroom scale (control group). The degree of weight-bearing was measured during six activities with sensor insoles. A mean load between 15 and 25 kg was defined as adherent.

RESULTS

There was no statistically significant difference in weight-bearing between the groups for all activities measured. For the sit-stand-sit activity, weight-bearing was within the adherence range of 15-25 kg (audio-biofeedback: 21.7 ± 16.6 kg; scale: 22.6 ± 13 kg). For standing, loading was below the lower threshold (10 ± 7 vs. 10 ± 10 kg). Weight-bearing was above the upper threshold for both groups for: walking (26 ± 11 vs. 34 ± 16), step-up (29 ± 18 vs. 34 ± 20 kg) and step-down (28 ± 15 vs. 35 ± 19 kg). Lower level of cognitive function, older age, and higher body mass index were correlated with overloading.

CONCLUSION

Audio-biofeedback delivered no statistically significant benefit over the scale method. Lower cognitive function, older age and higher body mass index were associated with overloading.

TRIAL REGISTRATION

Not applicable due not being a clinical trial and due to the cross-sectional design (one measurement point, no health intervention, no change in health of a person).

Do Patients Achieve "Full Weight-bearing" Immediately Following Application of Circular Frame Fixation of the Lower Limb?

Introduction

The decision to use circular frame fixation for lower limb trauma, or elective deformity correction, often accompanies the assertion that the patient will be able to fully weight-bear through the limb immediately following surgery.

Materials and methods

About 53 patients underwent retrospective review. Included in the study were current attendees of adult specialist physiotherapy, following circular frame application to the lower leg at our Institution between August 2018 and January 2020. Cases with incomplete data, cases given postoperative status of non-weight-bearing, those with physiotherapy follow-up conducted elsewhere, or cases of polytrauma were excluded from the study.Weight-bearing assessment and rehabilitation supervision were at the discretion of the physiotherapy team. The clinical concept of 'full weight-bearing' is poorly defined, but was documented in the context of displaying a stable gait using elbow crutches and subsequently without walking aids. Comparative data was analysed using an unpaired, two-tailed Welch's t-test.

Results

Mean postoperative time to full weight-bearing using crutches was 28.3 days (0-159) (n = 40).Mean postoperative time to independent full weight-bearing with no walking aids was 230.6 days (35-393), or 7.1 months (0-12) (n= 34).No significant differences were seen between:Frames for open injuries (n= 5) vs closed injuries (n = 17; p > 0.4).Joint-spanning constructs (n= 18) vs non-spanning constructs (n = 21; p > 0.6), orTreatment of intra-articular injuries (n = 14) vs extra-articular injuries (n = 17; p > 0.2).Interpretation of these results should be made with caution due to sample size.

Conclusion

The ability to permit patients to fully weight-bear immediately after surgery is often a distinct advantage of the circular frame over other fixation modalities, for a variety of indications. However, it does not follow that patients are capable of doing so; there is a long dependency on walking aids. This would appear to be the case irrespective of open/closed injuries, intra-/extra-articular injuries, or the use of a spanning construct across the knee or ankle.

How to cite this article

Craig A, Barron E, Sharma H, et al. Do Patients Achieve "Full Weight-bearing" Immediately Following Application of Circular Frame Fixation of the Lower Limb? Strategies Trauma Limb Reconstr 2024;19(1):40-44.

Validity of the activPAL and ActiGraph for measuring sitting time and steps in hospitalised orthopaedic patients with altered weight bearing

PURPOSE

To determine the criterion validity of the activPAL and ActiGraph for measuring steps and sitting/sedentary time, compared to observation, in people hospitalised following orthopaedic lower limb injury who were weight bearing (WB) (i.e., walking) or non-weight bearing (NWB) (i.e., hopping).

MATERIALS AND METHODS

Participants wore an activPAL and ActiGraph on the hip/thigh/unaffected (UA)/affected ankle (AA) while completing bouts of walking and sitting. Lin's concordance correlation coefficient, Bland-Altman methods, and ratio of agreement were used to compare device-measured to observed (videoed) step count, sitting/sedentary time.

RESULTS

In 42 participants, the ActiGraph demonstrated excellent concordance with the observed step count when worn on the ankle (LCC 0.91-0.92) compared to the hip (LCC 0.56) in participants that were WB. The ActiGraph AA achieved the highest concordance (LCC 0.71) with observed steps in participants NWB. The activPAL had poor concordance with observed steps, particularly at slow gait speeds, in participants that were WB (LCC 0.38-0.46), however was less influenced by gait speed and had good concordance in NWB participants (LCC 0.52-0.69). The activPAL (LCC 0.79-0.88) and ActiGraph UA (LCC 0.94) showed excellent concordance with observed sitting and sedentary time, respectively.

CONCLUSIONS

The ActiGraph worn at the ankle provided the most valid measure of steps in people who are WB and NWB following orthopaedic injury, while the activPAL was best for measuring sitting time.Implications for rehabilitationTo accurately measure both steps and sitting time in people with lower limb orthopaedic injuries, a combination of activity monitors should be used (i.e., ActiGraph for steps, activPAL for sitting time).The ActiGraph device when worn on the ankle demonstrated the strongest agreement with observed step count in people who were weight bearing and non-weight bearing.Caution is needed when using thigh- or hip-worn devices in people who walk slowly.

Temporary Partial Weight-Bearing Restriction in Elderly Patients Treated With a Plate Fixation After a Distal Femur Fracture had a Negative Long-Term Impact on Gait Recovery

Background

Restricted weight-bearing is still used after lower extremity fracture surgery in elderly patients. The long-term effect on gait recovery in elderly patients with distal femur fractures (DFF) and their ability to comply with the restrictive weight-bearing regime is unknown. This study aimed to investigate the effect of restricted postoperative weight-bearing on gait recovery (actual weight-bearing and cadence) during a 1-year follow-up.

Methods

This study evaluated secondary outcomes from a randomized controlled trial (32 patients ≥65 years, with a traumatic DFF). Internal fixation was achieved using an anatomical lateral plate. Patients were allocated to either immediate full weight-bearing (FWB) or partial weight-bearing (PWB) (30% of body weight) for 8 weeks. Pressure-sensitive sensors (F-scan™ system, Tekscan, Massachusetts, USA) were used to measure weight-bearing and cadence postoperatively and at 8-, 16-, and 52-week follow-ups. Twenty-six patients with at least 1 measurement were included.

Results

There was a statistically significant difference in actual weight-bearing between the PWB and FWB groups postoperatively of 32.3% (95% confidence interval CI, -50.0; -13.0, P < .001) and at the 8-week follow-up of 36.8% (95% CI -61.0; -18.0, P = .01), but not at later follow-ups. The PWB group presented a consistently lower cadence compared to the FWB group, which was statistically significant at the 16-week follow-up with 9.0 steps/min (95% CI -16.2; -1.1, P = .047) and 52-week follow-up with 9.3 steps/min (95% CI -18.0; -3.9, P = .009).

Conclusions

Restricting postoperative weight-bearing in elderly patients with a DFF had a significant effect on postoperative weight-bearing. The effect lingered with a delayed return to FWB and persistent significantly lower cadence in the PWB group. These findings suggest that even temporary weight-bearing restrictions most likely have negative long-term effects on gait function at 1 year and, therefore, cannot be recommended.

Foot radiographic angle variation as a function of weightbearing magnitude

Weightbearing radiographs are widely used to investigate foot disorders. However, it is unclear how imaging during partial weightbearing affects foot alignment measurements. This study aimed to determine a partial weightbearing threshold that yields consistent measurements of various radiographic angles. Eighteen normal fresh-frozen cadaveric foot specimens were dissected and prepared for mechanical testing using a custom-designed, computed tomography-compatible loading frame. Specimens were placed in a neutral ankle position and scanned in five axial loading conditions (0%, 12.5%, 25%, 37.5%, and 50% bodyweight) using weightbearing computed tomography. (Note 50% bodyweight per foot represents full bodyweight in quiet stance.) The lateral first talometatarsal and calcaneal pitch angles were measured on lateral radiographic projections, and the hallux valgus angle and first-second, fourth-fifth, and first-fifth intermetatarsal angles were measured on axial projection images. The lateral first talometatarsal angle decreased significantly with increased bodyweight loading (p < 0.01). Mean significant decreases in the lateral first talometatarsal angle compared to 0% were 6.6° for 12.5%, 7.6° for 25%, 8.8° for 37.5%, and 10.0° for 50% bodyweight loading; 12.5% to 50% was also significant. There was no significant differences between other loading condition pairings or with increased axial load at other angles. The medial longitudinal arch flattened with increasing axial load, resulting in a decreased lateral first talometatarsal angle. However, this radiographic parameter did not change between the 25% and 50% bodyweight conditions, indicating that partial weightbearing imaging (between 12.5% and 25% bodyweight) might be enough to reproduce the sagittal foot alignments observed under full weightbearing conditions in normal feet.

Walk-IT: An Open-Source Modular Low-Cost Smart Rollator

Rollators are widely used in clinical rehabilitation for gait assessment, but gait analysis usually requires a great deal of expertise and focus from medical staff. Smart rollators can capture gait parameters autonomously while avoiding complex setups. However, commercial smart rollators, as closed systems, can not be modified; plus, they are often expensive and not widely available. This work presents a low cost open-source modular rollator for monitorization of gait parameters and support. The whole system is based on commercial components and its software architecture runs over ROS2 to allow further customization and expansion. This paper describes the overall software and hardware architecture and, as an example of extended capabilities, modules for monitoring dynamic partial weight bearing and for estimation of spatiotemporal gait parameters of clinical interest. All presented tests are coherent from a clinical point of view and consistent with input data.

Effects of assistive insole feedback training on immediate and multi-day partial weight bearing retention during walking: A pilot study

BACKGROUND

Adherence to partial weight bearing (PWB) plays a crucial role in early rehabilitation and motor control. Dynamic biofeedback insole systems provide a supportive function on immediate PWB adherence, while important long-term retention effects and potential advantages to a conventional static training remain unknown.

RESEARCH QUESTION

Is acoustic insole feedback training effective for the retention of prescribed PWB adherence and is there any advantage relative to static training using a conventional bathroom scale? Methods Twenty-four volunteers were randomized into two groups receiving biofeedback training (N = 12) via a mobile insole system (Loadsol®) or conventional training using a bathroom scale (N = 12). After initial PWB training (20 kg) of one randomized leg, the immediate and one-week retention effects were analysed using mean and maximum load (N) and overload rate (%). Statistical analysis was performed using a two-way repeated measures ANOVA with post-hoc pairwise comparisons (p < 0.05).

RESULTS

A significantly (p < 0.001) improved immediate and long-term PWB adherence was found for the insole feedback group during walking. A significant (p < 0.001) reduction of the overload rate by 86% was found for the insole feedback group when compared to the conventional training group after one week. Significant (p < 0.01) reductions by 51% and 46% was also found for the mean and maximum load in the insole feedback group when compared to the conventional training group.

SIGNIFICANCE

The use of insole feedback systems can serve as a viable tool to become familiar with PWB and to provide optimal retention of specified loads. Therefore, such systems serve as an advantageous training intervention to maintain a prescribed PWB during locomotion.

Immediate Full Weight-Bearing Versus Partial Weight-Bearing After Plate Fixation of Distal Femur Fractures in Elderly Patients. A Randomized Controlled Trial

Introduction

After surgery for distal femur fractures in elderly patients, weight-bearing is commonly restricted. Immediate non-restrictive weight-bearing might have beneficial effects. There are no randomized studies on the topic. The purpose of this study was to compare the functional outcome between immediate full weight-bearing (FWB) as tolerated and partial weight-bearing (PWB) during the first 8 weeks following plate fixation of distal femur fractures in elderly patients.

Methods

Patients aged 65 years or older with distal femur fractures of AO/OTA types 33 A2, A3, B1, B2, C1, and C2 were included. Exclusion criteria were impaired cognitive function, concomitant injuries, or inability to follow the postoperative regimen. Internal fixation was achieved with an anatomical lateral distal femur plate applied as a strictly bridge-plating construct. The primary outcome measure was the function index of the short musculoskeletal functional assessment (SMFA) after 52 weeks from injury.

Results

Thirty-two patients were randomized to FWB (n = 11) or PWB (n = 21). After 16 and 52 weeks, there were no differences in the mean SMFA function index between FWB and PWB (36 vs 43, P = .42 and 52 vs 40, P = .18, respectively) nor in the mean EuroQol 5-dimension index or range of motion (ROM). Overall, the SMFA function index was higher at 52 weeks compared with before injury (44 vs 30, P = .001) as was the mean bothersome index (37 vs 21, P = .011). There was no clear difference in the occurrence of adverse events between the treatment groups.

Conclusions

There were no differences in functional outcome, adverse events, or ROM between immediate FWB and PWB following plate fixation for a distal femur fracture in elderly patients. A distal femur fracture has a negative effect on the functional status of elderly patients that persists at least up to 1 year following injury.

Weight-bearing in Trauma Surgery (WiTS) Study: A national survey of UK Trauma & Orthopaedic multidisciplinary health professionals

INTRODUCTION

Weight-bearing (WB) status following a fracture or surgical fixation is an important determinant of the mechanical environment for healing. In order for healthcare professionals to communicate and understand the extent of bearing weight through a limb, clear terminology must be used. There is widespread variation in the usage and definitions of WB terminology in the literature and clinical practice. This study sought to define the understanding and extent of variation across the United Kingdom.

METHODS

A nationwide online survey of UK-based Trauma & Orthopaedic (T&O) multidisciplinary healthcare professionals was conducted. Participants answered seven questions assessing their usage and understanding of various WB terminology.

RESULTS

A total of 707 responses were received: 48% by doctors, 32% by physiotherapists, 13% by occupational therapists and 7% from other healthcare professionals. In terms of understanding of WB terminology with respect to percentage body weight (BW), 89% of respondents interpret 'full WB' as 100% BW, 97% interpret 'non WB' as 0% BW, 80% interpret 'partial WB' as 50% BW, and 89% interpret 'touch/toe-touch WB' as 10% or 20% BW. There were statistically significant differences between the responses of doctors and therapists for these four terms, with doctors tending to give higher %BW values. 'Protected WB' and 'WB as tolerated' had less consensus and more variability in responses. The majority (68%) of respondents do not usually quantify terminology such as 'partial WB' with a value, and 94% agreed that standardisation of WB terminology would improve communication amongst professionals.

CONCLUSION

This study provides evidence of the substantial variation in the understanding of WB terminology amongst healthcare professionals, which likely results in ambiguous rehabilitation advice. Existing literature has shown that patients struggle to comply with terms such as 'partial weight-bearing'. We recommend consensus within the T&O multidisciplinary community to standardise and define common weight-bearing terminology.

Longitudinal changes in lower limb joint loading up to two years following tibial plateau fracture

BACKGROUND

Tibial plateau fractures are one of the most common intra-articular fractures resulting from high or low energy impact trauma. Few studies have assessed postoperative outcomes of these fractures with respect to changes in knee joint loading post-surgery. This gait analysis study compared lower limb joint loading up to two years post-surgery.

METHODS

Twenty patients (range 27-67 years; 9:11(male:female)) were treated with open reduction internal fixation and instructed to weight bear as tolerated immediately following surgery. Joint loading at the hip, knee and ankle were assessed at six time points post-operatively up to two years. Gait analyses were performed at each time point and a musculoskeletal model was used to compute external joint moments for the lower limb.

RESULTS

Hip flexion and extension (P = <0.001, P = <0.001), knee flexion (P = 0.014) and ankle plantarflexion moments (P = <0.001) showed significant increases with time. The hip flexion moment increased between six months and one year (mean difference = 0.16 Nm/kg) but did not increase thereafter (mean difference = 0.01 Nm/kg). Knee flexion and extension, and ankle plantarflexion moments increased up to six months (mean difference = 0.22 Nm/kg, 0.14 Nm/kg, 0.80 Nm/kg, respectively), but no further differences were seen with time from six months postoperative.

DISCUSSION

The greatest changes in joint loads were observed at the hip and ankle within the first six months, likely a result of mechanical adaptations attempting to account for limited motion at the knee. Knee joint loading plateaued beyond six months suggesting functional outcomes are largely reliant on postoperative management within the initial three months while the bone is healing.

Weight-Supported Walking Assist Device for Knee Osteoarthritis Patients

Knee osteoarthritis patients have pain in their knee and it can become difficult to walk depending on the progress of symptoms. After performing chondrocyte implantation, it is necessary to reduce the load on the knee joint until the implanted cartilage is integrated. The purposes of this study were to develop a device that enables the user to walk and reduced the weight on the knee joint and to confirm basic performance of the device through experiments. The device was composed of a seat for supporting the body weight of the user, a prosthetic knee, and the floor reaction force sensor shoes. Experiments were conducted to confirm the basic performance of the device. As a result, an able-bodied participant who wore the device was able to walk while unloading two-thirds of their body weight onto their knee. As a result of gait analysis, it was found that the gait did not change significantly even when the device was worn.

Increased therapy demand and impending loss of previous residence status after proximal femur fractures can be determined by continuous gait analysis - A clinical feasibility study

Proximal femur fractures account for increased healthcare costs whenever patients are unable to return to their previous state of residence. Studies suggest that patients benefit from early weight-bearing, yet compliance to weight-bearing regimes is poorly investigated. Aim of the study was thus to show the clinical feasibility of a new measurement tool able to determine continuous weight-bearing behavior after intramedullary nail osteosynthesis of intertrochanteric femur fractures, assess the influence of weight-bearing on clinical outcome and determine rehabilitation demand based on early postoperative gait performance. In an observational study, gait data of 22 patients with intertrochanteric femur fractures were evaluated. During the inpatient stay patients were continuously monitored with a gait analysis insole. Primary outcome was the amount of weight-bearing reached. Short-term functional outcome, as well as return to the previous state of living were evaluated in relation to weight-bearing and activity during the inpatient stay. With the presented technique continuous gait data of all patients during postoperative mobilization could be obtained. Only 13 patients reached full weight-bearing. The technique was feasible to determine correlations between weight-bearing and outcome, as well as between gait activity and outcome. Significant gait differences between patients able to return to their previous state of living and those who could not were seen. Dynamic insole measurements are feasible to continuously determine the postoperative gait performance. Their postoperative use showed, that the continuous compliance to permissive weight-bearing after intertrochanteric fractures is low. The presented measurement technique has the potential to identify patients at risk for reduced outcome and impending loss of previous residence status. Further studies will have to investigate the effects of technology assisted "patient at risk" identification and adapted therapy on clinical outcome.

[A new continuous gait analysis system for ankle fracture aftercare]

BACKGROUND

Correct aftercare following lower extremity fractures remains a controversial issue. Reliable, clinically applicable weight-bearing recommendations have not yet been defined. The aim of the current study was to establish a new gait analysis insole during physical therapy aftercare of ankle fractures to test patients' continuous, long-term compliance to partial weight-bearing restrictions and investigate whether patients can estimate their weight-bearing compliance.

MATERIALS AND METHODS

The postoperative gait of 14 patients after operative treatment of Weber B-type ankle fractures was monitored continuously for six weeks (OpenGO, Moticon GmbH, Munich). All patients were instructed and trained by physical therapists on how to maintain partial weight-bearing for this time. Discontinuous (three, six and twelve weeks) clinical (patient questionnaire, visual analogue pain score [VAS]) and radiographic controls were performed.

RESULTS

Despite the set weight-bearing limits, individual ranges for overall weight-bearing (range 5-107% of the contralateral side) and patient activity (range 0-366 min/day) could be shown. A good correlation between weight-bearing and pain was seen (r_s = -0.68; p = <0.0001). Patients significantly underestimated their weight-bearing time over the set limit (2.3 ± 1.4 min/day vs. real: 12.6 ± 5.9 min/day; p < 0.01).

CONCLUSIONS

Standardized aftercare protocols and repeated training alone cannot ensure compliance to postoperative partial weight-bearing. Patients unconsciously increased weight-bearing based on their pain level. This study shows that new, individual and possibly technology-assisted weight-bearing regimes are needed. The introduced measuring device is feasible to monitor and steer patient weight-bearing during future studies.

Immediate weight bearing after plate fixation of fractures of the tibial plateau

BACKGROUND

Proximal articular fractures of the tibia are commonly stabilised with internal fixation using plates and screws. There is a lack of evidence and conflicting guidelines as to the most suitable post-operative rehabilitation regime including weight bearing status. There are numerous physiological and socioeconomic benefits of early weight bearing after orthopaedic surgery, but concerns remain around loss of fracture reduction. Therefore, the aim of this study is to investigate whether the weight bearing status after tibial plateau plate fixation is associated with any loss of reduction or articular collapse.

METHODS

We retrospectively analysed data from our prospectively collected major trauma centre database. All tibial plateau fractures that required open reduction and internal fixation with plate and screws were included. The immediate post-operative weight bearing status of these patients was recorded. Group I consisted of those patients that were either non-weight bearing or touch weight bearing for the first six post-operative weeks. Group II consisted of patients who were instructed to weight bear fully (as tolerated) immediately after the operation. Radiographs were taken on day one post-operation, at six weeks and at three months and analysed for fracture displacement and joint depression or loss of fixation.

RESULTS

A total of 90 patients were included in the study. Group I (non-weight bearing or touch weight bearing) consisted of 60 patients (67%). Group II (full weight bearing as tolerated) consisted of 30 patients (33%). The follow up radiographs demonstrated no failure of fixation in either study group. One patient from the weight bearing group had >1 mm joint depression (4 mm) identified at the first follow up, which did not progress.

CONCLUSIONS

This study shows immediate post-operative full weight bearing does not affect the fixation or cause articular collapse up to three months after surgery and thus we propose that patients should be allowed to weight bear immediately after surgical stabilisation of tibial plateau fractures. This will enable patients to benefit from the positive effects on fracture healing of early weight bearing post-surgery and avoid the complications of non-weight bearing without loss of fixation or articular collapse.

How do orthopaedic surgeons and rehabilitation professionals interpret and assess 'toe touch' weight bearing and 'partial' weight bearing status in the rehabilitation setting?

Aim

To compare the interpretation of toe touch weight bearing (TTWB) and partial weight bearing (PWB) among orthopaedic surgeons, rehabilitation professionals and patients.

Methodology

78 consultant and middle-grade orthopaedic surgeons in the UK completed a questionnaire. 64 rehabilitation professionals (including physiotherapists) at Defence Medical Rehabilitation Centre Headley Court were also recruited. Both groups provided their interpretation of TTWB and PWB as a percentage of total body weight (%TBW). Each rehabilitation professional, then applied what they interpreted to be TTWB and PWB using a Lasar Posture weighing device. The predicted values were compared with the actual values demonstrated.

Results

There was no significant difference between orthopaedic surgeons and rehabilitation professionals in their interpretation of TTWB and PWB, however there was a wide range of responses. There was a significant difference between the predicted %TBW and the actual values demonstrated by the ‘educated patient’ (mean difference 4.8 (TTWB) and 22.9 (PWB)).

Conclusion

Healthcare professionals vary greatly in their interpretation of the terms TTWB and PWB. Therefore, for a consistency in rehabilitation delivery the terms should not be used in isolation without a further descriptor. Static measures of weight application are lower than people think they are applying. We encourage the use of loading practice with a scale to reassure and educate patients.

Current Concepts and Controversies in Rehabilitation After Surgery for Multiple Ligament Knee Injury

PURPOSE OF REVIEW

The purpose of this manuscript is twofold: (1) to review the literature related to rehabilitation after surgery for multiple ligament knee injury (MLKI) and after isolated surgery for the posterior cruciate ligament (PCL), posterolateral corner (PLC), and medial side of the knee and (2) to present a hierarchy of anatomic structures needing the most protection to guide rehabilitation.

RECENT FINDINGS

MLKIs continue to be a rare but devastating injury. Recent evidence indicates that clinicians may be providing too much protection from early weight bearing and range of motion, but an accelerated approach has not been rigorously tested. Consideration of the nature and quality of surgical procedures (repair and reconstruction) can help clinicians determine the structures needing the most protection during the rehabilitation period. The biomechanical literature and prior clinical experience can aid clinicians to better structure rehabilitation after surgery for MLKI and improve clinical outcome for patients.

Biofeedback in Partial Weight Bearing: Validity of 3 Different Devices

Study Design Controlled laboratory study to assess criterion-related validity, with a cross-sectional within-subject design. Background Patients with orthopaedic conditions have difficulties complying with partial weight-bearing instructions. Technological advances have resulted in biofeedback devices that offer real-time feedback. However, the accuracy of these devices is mostly unknown. Inaccurate feedback can result in incorrect lower-limb loading and may lead to delayed healing. Objectives To investigate validity of peak force measurements obtained using 3 different biofeedback devices under varying levels of partial weight-bearing categories. Methods Validity of 3 biofeedback devices (OpenGo science, SmartStep, and SensiStep) was assessed. Healthy participants were instructed to walk at a self-selected speed with crutches under 3 different weight-bearing conditions, categorized as a percentage range of body weight: 1% to 20%, greater than 20% to 50%, and greater than 50% to 75%. Peak force data from the biofeedback devices were compared with the peak vertical ground reaction force measured with a force plate. Criterion validity was estimated using simple and regression-based Bland-Altman 95% limits of agreement and weighted kappas. Results Fifty-five healthy adults (58% male) participated. Agreement with the gold standard was substantial for the SmartStep, moderate for OpenGo science, and slight for SensiStep (weighted ± = 0.76, 0.58, and 0.19, respectively). For the 1% to 20% and greater than 20% to 50% weight-bearing categories, both the OpenGo science and SmartStep had acceptable limits of agreement. For the weight-bearing category greater than 50% to 75%, none of the devices had acceptable agreement. Conclusion The OpenGo science and SmartStep provided valid feedback in the lower weight-bearing categories, and the SensiStep showed poor validity of feedback in all weight-bearing categories. J Orthop Sports Phys Ther 2016;46(11):-1. Epub 12 Oct 2016. doi:10.2519/jospt.2016.6625.

Biofeedback in Partial Weight Bearing: Usability of Two Different Devices from a Patient's and Physical Therapist's Perspective

Background

Partial weight bearing is frequently instructed by physical therapists in patients after lower-limb trauma or surgery. The use of biofeedback devices seems promising to improve the patient’s compliance with weight-bearing instructions. SmartStep and OpenGo-Science are biofeedback devices that provide real-time feedback. For a successful implementation, usability of the devices is a critical aspect and should be tested from a user’s perspective.

Aim

To describe the usability from the physical therapists’ and a patients’ perspective of Smartstep and OpenGo-Science to provide feedback on partial weight bearing during supervised rehabilitation of patients after lower-limb trauma or surgery.

Methods

In a convergent mixed-methods design, qualitative and quantitative data were collected. Usability was subdivided into user performance, satisfaction and acceptability. Patients prescribed with partial weight bearing and their physical therapists were asked to use SmartStep and OpenGo-Science during supervised rehabilitation. Usability was qualitatively tested by a think-aloud method and a semi-structured interview and quantitatively tested by the System-Usability-Scale (SUS) and closed questions. For the qualitative data thematic content analyses were used.

Results

Nine pairs of physical therapists and their patients participated. The mean SUS scores for patients and physical therapists were for SmartStep 70 and 53, and for OpenGo-Science 79 and 81, respectively. Scores were interpreted with the Curved Grading Scale. The qualitative data showed that there were mixed views and perceptions from patients and physical therapists on satisfaction and acceptability.

Conclusion

This study gives insight in the usability of two biofeedback devices from the patient’s and physical therapist’s perspective. The overall usability from both perspectives seemed to be acceptable for OpenGo-Science. For SmartStep, overall usability seemed only acceptable from the patient’s perspective.

Implication

The study findings could help clinicians to decide which biofeedback device is appropriate for their given situation and provide information for future development of biofeedback devices.

Partial weight bearing of the tibia

INTRODUCTION

Partial weight bearing is part of treatment schemes in orthopedic surgery and traumatology. The aim of the present study was to explore to what degree ground reaction forces during partial weight bearing of the lower leg are related to given instructions and to tibia deformation.

MATERIALS AND METHODS

Tibia deformation (torsion, medio-lateral and anterio-posterior bending) was measured for rear foot and forefoot loading, 10kg, 20kg and half body weight instructions compared to full loading in five healthy male subjects using the "Optical Segment Tracking" approach, a motion-capturing based method that uses monocortically fixed bone screws.

RESULTS

1. Ground reaction force was a good indicator of tibia deformation. 2. Participants significantly under-loaded during half-body weight instructions (P<0.001) while they overloaded when loading the forefoot only. 3. Partial-loading instructions led to a highly significant and systematic reduction in peak ground reaction force (GRFpk) in all three types of tibia deformation with substantial variation between measurements. 4. Forefoot usage was associated with significant, albeit moderate increases in GRFpk (P=0.0031), in AP-bending (P=0.0027) and in torsion (P<0.001), compared to rear foot loading.

DISCUSSION

These findings result in the following clinical "lessons learned": 1. GRF is a good reflection of loading-induced deformation of the tibia. 2. GRFs are hard to control by subjects/patients. 3. The expectation that forefoot-loading results in larger tibia deformation could not be confirmed in our study. 4. When aiming at a reduction in tibia deformation, rear-foot loading is more preferable than forefoot loading.

Are current methods of partial weight-bearing instruction accurately translating to crutch-assisted gait?

Background/Aims:

Partial weight-bearing protocols are commonly incorporated into hospital, clinical and field-based rehabilitation to enhance recovery, particularly in patients following cartilage surgeries. Overloading can affect healing time and the stability or integrity of the healing structure, however underloading can also be detrimental, as adequate weight bearing encourages the healing process—for example, osteoblastic stimulation. Therefore, accurate reproducibility of these protocols could be considered essential to the rehabilitation process. The aim of this study was to determine the accuracy with which weight-bearing protocols (20%, 50% or 80% of body weight) could be reproduced shortly after being taught.

Methods:

Thirty participants were taught three partial weight-bearing protocols (20%, 50% and 80% of body weight), using bathroom scales. Participants ability to reproduce their target load for each protocol was assessed statically using bathroom scales and dynamically with a force plate using a three-point elbow crutch-assisted gait. Participants were assessed 10 minutes after being taught. Errors between actual and target load during these trials was calculated.

Findings:

Accuracy assessed with scales was comparatively good for all target loads, however dynamic trials using the force plate showed an inverse relationship between all error measures and target loads (i.e. 20% > 50% > 80% body weight; all P<0.01). The peak error was double the intended load at 20% of body weight (95% CI: 11.9% body weight, 24.1% body weight). At 80% of body weight, the peak error was not significantly different from zero.

Conclusions:

The static method of instruction of partial weight-bearing protocols, using bathroom scales, does not seem to translate accurately to dynamic motion, and therefore affects adherence to medical instruction. Practitioners should be aware of the potential errors in reproducing these loads and the potential effect on rehabilitation. These results would suggest that practitioners should be cautious when using bathroom scales to teach partial weight-bearing protocols and not to rely on them to assess reproduction accuracy during gait.

A novel tool for continuous fracture aftercare - Clinical feasibility and first results of a new telemetric gait analysis insole

Weight bearing after lower extremity fractures still remains a highly controversial issue. Even in ankle fractures, the most common lower extremity injury no standard aftercare protocol has been established. Average non weight bearing times range from 0 to 7 weeks, with standardised, radiological healing controls at fixed time intervals. Recent literature calls for patient-adapted aftercare protocols based on individual fracture and load scenarios. We show the clinical feasibility and first results of a new, insole embedded gait analysis tool for continuous monitoring of gait, load and activity. Ten patients were monitored with a new, independent gait analysis insole for up to 3 months postoperatively. Strict 20 kg partial weight bearing was ordered for 6 weeks. Overall activity, load spectrum, ground reaction forces, clinical scoring and general health data were recorded and correlated. Statistical analysis with power analysis, t-test and Spearman correlation was performed. Only one patient completely adhered to the set weight bearing limit. Average time in minutes over the limit was 374 min. Based on the parameters load, activity, gait time over 20 kg weight bearing and maximum ground reaction force high and low performers were defined after 3 weeks. Significant difference in time to painless full weight bearing between high and low performers was shown. Correlation analysis revealed a significant correlation between weight bearing and clinical scoring as well as pain (American Orthopaedic Foot and Ankle Society (AOFAS) Score rs=0.74; Olerud-Molander Score rs=0.93; VAS pain rs=-0.95). Early, continuous gait analysis is able to define aftercare performers with significant differences in time to full painless weight bearing where clinical or radiographic controls could not. Patient compliance to standardised weight bearing limits and protocols is low. Highly individual rehabilitation patterns were seen in all patients. Aftercare protocols should be adjusted to real-time patient conditions, rather than fixed intervals and limits. With a real-time measuring device high performers could be identified and influenced towards optimal healing conditions early, while low performers are recognised and missing healing influences could be corrected according to patient condition.

Incompliance of total hip arthroplasty (THA) patients to limited weight bearing

INTRODUCTION

Limited weight bearing of the lower extremity is a commonly applied procedure in orthopedic rehabilitation following trauma surgery and joint replacement. The compliance of patients with limited weight bearing after cementless total hip arthroplasty has not yet been surveyed using sensor-loaded insoles. The objective of this study was to investigate foot loadings in patients after THA under the assumption of limited weight bearing.

METHODS

Peak pressures for the hindfoot, midfoot and forefoot were obtained from 14 patients (10 women, 4 men, age 63 ± 12 years, height 172 ± 9 cm, weight 92 ± 20 kg, BMI 31 ± 6 kg/m(2)) by means of dynamic pedobarography, with full weight bearing preoperatively (baseline) and at 8-10 days after cementless total hip arthroplasty, walking again on even floor, and also walking upstairs and downstairs with a restriction of weight bearing to 10 % body weight, taught by an experienced physiotherapist with a bathroom scale.

RESULTS

Foot loadings with limited weight bearing on even floor remained up to 88 % from full weight bearing preoperatively. Walking upstairs and downstairs under the same condition was approximately equal to a bisection of peak pressures from full weight bearing.

CONCLUSIONS

Patients following cementless do not comply with limited weight bearing when they are trained by the use of a bathroom scale.

Haptic biofeedback for improving compliance with lower-extremity partial weight bearing

After lower-extremity orthopedic trauma and surgery, patients are often advised to restrict weight bearing on the affected limb. Conventional training methods are not effective at enabling patients to comply with recommendations for partial weight bearing. The current study assessed a novel method of using real-time haptic (vibratory/vibrotactile) biofeedback to improve compliance with instructions for partial weight bearing. Thirty healthy, asymptomatic participants were randomized into 1 of 3 groups: verbal instruction, bathroom scale training, and haptic biofeedback. Participants were instructed to restrict lower-extremity weight bearing in a walking boot with crutches to 25 lb, with an acceptable range of 15 to 35 lb. A custom weight bearing sensor and biofeedback system was attached to all participants, but only those in the haptic biofeedback group were given a vibrotactile signal if they exceeded the acceptable range. Weight bearing in all groups was measured with a separate validated commercial system. The verbal instruction group bore an average of 60.3±30.5 lb (mean±standard deviation). The bathroom scale group averaged 43.8±17.2 lb, whereas the haptic biofeedback group averaged 22.4±9.1 lb (P<.05). As a percentage of body weight, the verbal instruction group averaged 40.2±19.3%, the bathroom scale group averaged 32.5±16.9%, and the haptic biofeedback group averaged 14.5±6.3% (P<.05). In this initial evaluation of the use of haptic biofeedback to improve compliance with lower-extremity partial weight bearing, haptic biofeedback was superior to conventional physical therapy methods. Further studies in patients with clinical orthopedic trauma are warranted.

Validating a simple discharge planning tool following hospital admission for an isolated lower limb fracture

BACKGROUND

Early, accurate prediction of discharge destination from the acute hospital assists individual patients and the wider hospital system. The Trauma Rehabilitation and Prediction Tool (TRaPT), developed using registry data, determines probability of inpatient rehabilitation discharge for patients with isolated lower limb fractures.

OBJECTIVE

The aims of this study were: (1) to prospectively validatate the TRaPT, (2) to assess whether its performance could be improved by adding additional demographic data, and (3) to simplify it for use as a bedside tool.

DESIGN

This was a cohort, measurement-focused study.

METHODS

Patients with isolated lower limb fractures (N=114) who were admitted to a major trauma center in Melbourne, Australia, were included. The participants' TRaPT scores were calculated from admission data. Performance of the TRaPT score alone, and in combination with frailty, weight-bearing status, and home supports, was assessed using measures of discrimination and calibration. A simplified TRaPT was developed by rounding the coefficients of variables in the original model and grouping age into 8 categories. Simplified TRaPT performance measures, including specificity, sensitivity, and positive and negative predictive values, were evaluated.

RESULTS

Prospective validation of the TRaPT showed excellent discrimination (C-statistic=0.90 [95% confidence interval=0.82, 0.97]), a sensitivity of 80%, and specificity of 94%. All participants able to weight bear were discharged directly home. Simplified TRaPT scores had a sensitivity of 80% and a specificity of 88%.

LIMITATIONS

Generalizability may be limited given the compensation system that exists in Australia, but the methods used will assist in designing a similar tool in any population.

CONCLUSIONS

The TRaPT accurately predicted discharge destination for 80% of patients and may form a useful aid for discharge decision making, with the simplified version facilitating its use as a bedside tool.

Patient compliance with postoperative lower extremity touch-down weight-bearing orders at a level I academic trauma center

After lower extremity fracture or surgery, physicians often prescribe limited weight bearing. The current study was performed to evaluate teaching and compliance of touch-down weight bearing (defined as 25 lb) at a level I academic trauma center. A survey was distributed to physical therapists (PTs) from the orthopedic ward to gauge their training methods and their confidence in patients' ability to comply. Patients with recommended touch-down weight bearing were then evaluated on the day of discharge and again at their first follow-up appointment using the SmartStep weight-bearing measurement device (Andante Medical Devices, Inc, White Plains, New York). Fifteen PTs completed the survey (average of 14 years in practice). Inconsistency was observed in weight-bearing teaching methods: verbal cues were used 87% of the time, tactile methods were used 41%, demonstration was used 23%, and a scale was used only 1%. Limited confidence was found in the instruction efficacy by those surveyed. Twenty-one patients were seen the day of discharge and 18 of those were seen at first follow-up. At discharge, average minimum and maximum weight bearing were 3.2 and 30.2 lb, respectively. Only 31% of steps were within an acceptable range of 15 to 35 lb. At first follow-up, average minimum and maximum weight bearing were 12.2 and 50.8 lb, respectively. Only 27% of steps were within the acceptable range. The majority of steps were less than the prescribed weight at discharge, whereas the majority of steps were greater than the prescribed weight at first follow-up. These data suggest that more uniform and effective teaching methods for prescribed weight-bearing orders are warranted assuming compliance is an important clinical objective.

Orthopedic inpatients’ ability to accurately reproduce partial weight bearing orders

Partial weight bearing is often prescribed for patients with orthopedic injuries. Patients’ ability to accurately reproduce partial weight bearing orders is variable, and its impact on clinical outcomes is unknown. This observational study measured patients’ ability to reproduce partial weight bearing orders, factors influencing this, patients’ and physiotherapists’ ability to gauge partial weight bearing accuracy, and the effect of partial weight bearing accuracy on long-term clinical outcomes. Fifty-one orthopedic inpatients prescribed partial weight bearing were included. All received standard medical/nursing/physiotherapy care. Physiotherapists instructed patients in partial weight bearing using the hand-under-foot, bathroom scales, and/or verbal methods of instruction. Weight bearing was measured on up to 3 occasions during hospitalization using a force-sensitive insole. Factors that had the potential to influence partial weight bearing accuracy were recorded. Patients and their physiotherapists rated their perception of partial weight bearing accuracy. Three-month clinical follow-up data were retrieved from medical records. The majority of patients (72% or more) exceeded their target load, with mean peak weight bearing as high as 19.3 kg over target load (285% of target load). Weight bearing significantly increased over the 3 measurement occasions (P<.001) and was significantly associated with greater body weight (P=.04). Patients and physiotherapists were unable to accurately gauge partial weight bearing accuracy. The incidence of clinically important complications at 3 months was 9% and not significantly associated with partial weight bearing accuracy during hospitalization (P≥.45). Patients are unable to accurately reproduce partial weight bearing orders when trained with the hand-under-foot, bathroom scales, or verbal methods of instruction.

Referent body weight values in over ground walking, over ground jogging, treadmill jogging, and elliptical exercise

OBJECTIVES

I. To evaluate average percentage body weight (APBW) values and weight-bearing distribution percentages (WBDP) between four common sports activities in a referent adult population. II. To suggest clinical implications.

DESIGN

Original research study.

SETTING

Lerner Sports Center, Hebrew University, Mount Scopus, Jerusalem, Israel.

PARTICIPANTS

Seventy-five asymptomatic volunteers, mean age=33.5 (19-72) years SD=15.1, mean weight (kg)=70.7 (43-113) SD=14.1.

INTERVENTIONS

Four tests were conducted: 1. Overground walking (OGW) over a 20 m distance, 2. Overground jogging (OGJ) over a 20 m distance, 3. Treadmill jogging (TJ) at a constant speed of 8.5 km/h for a 15-second interval and 4. Elliptical exercise (EE) for a 20 second period at a resistance and incline level of 10, and a steady pace within the range of 70-95 steps/min.

MAIN OUTCOME MEASURE

The Smartstep™ weight-bearing gait analysis system.

RESULTS

The APBW value on the entire foot in OGW was 112% (SD=15.57), in OGJ, 201% (SD=31.24, in TJ, 175% (SD=25.48) and in EE, 73% (SD=13.8). Regarding WBDP, the swing phase in OGJ and TJ was significantly longer than the stance phase (p<0.05). OGW resulted in significantly less swing phase compared to OGJ and TJ (p<0.05).

CONCLUSIONS

EE significantly reduces weight-bearing as compared to other common functional and sporting activities. These findings may assist the rehabilitation team when considering returning individuals back to early activity following certain bony or soft tissue pathologies or lower-limb surgical procedures. This information is also useful from a repetitive loading standpoint (to prevent overuse injury) or for exercise recommendations for those at greater risk for exacerbating chronic joint pathology.

In vivo hip joint loads during three methods of walking with forearm crutches

BACKGROUND

Patients with osteoarthritis, joint implants or fractures use crutches in order to reduce lower limb loading. However, insufficient information exists on how much the loading is then in fact reduced. This situation was studied by using seven patients who had instrumented hip implants.

METHODS

Part I: To investigate the effectiveness of forearm crutches, crutch and hip joint contact forces were measured in seven patients with instrumented hip prostheses. Additionally, the bending moments in the implant neck and torsion around its stem were determined. Reductions of peak loads during 3, 4, and 2-point gaits were compared with loads present when walking without crutches. Part II: This examines joint load reduction during a 4-point gait from one to 12 weeks post-operatively.

FINDINGS

Part I: During a 3, 4, and 2-point gait, the joint force was 17, 12, and 13% lower than it was while walking without crutches. The corresponding reductions of the bending moment were 16, 11, and 12%, while the maximum torque decreased by 19, 21, and 10%. Part II: The reductions of contact forces in comparison with walking without crutches were highest during the first 4 weeks after surgery. One and 4 weeks post-operatively, the force maximum was 21 and 8% lower than it was after 3 months. When compared with the initial values of the 1st week, crutch forces decreased by 28% in the 4th week and by 38% in the 3rd month.

INTERPRETATION

Average reductions of the joint load by more than 20% are achieved only during the first 4 post-operative weeks. Because fractures are in most cases relatively stable after 6 weeks, and bone ingrowth into implant interfaces is nearly finished after this time, a single crutch and a 2-point gait can be prescribed during the 5th and 6th post-operative week.

Effect of age on partial weight-bearing training

Biofeedback devices are increasingly used to train orthopedic patients to comply with partial weight-bearing instructions for an injured or postoperative extremity. In a previous study, the authors showed that biofeedback was effective in training young participants. However, because many partial weight-bearing orthopedic patients are of advanced age, the current study was designed to test the effect of age on partial weight-bearing training. Fifty asymptomatic participants aged between 20 and 78 years completed 3 interventions: (1) verbal instructions on weight bearing, (2) training with a bathroom scale, and (3) training with a biofeedback device. Participants given only verbal touchdown weight-bearing instructions (25 lb) initially bore an average of 61.25±4.80 lb. This was reduced to 51.50±4.47 lb after training with a bathroom scale and further reduced to 30.01±2.33 lb after biofeedback training. Likewise, participants given verbal partial weight-bearing instructions (75 lb) initially bore an average of 89.06±5.58 lb. No improvement was observed with the use of a bathroom scale (average, 88.47±4.75 lb). After training with the biofeedback device, weight bearing improved to an average of 68.11±2.46 lb. Mixed-model analysis revealed that age was not a significant predictor of compliance. However, a higher body mass index and male sex were predictive of worse compliance and heavier weight bearing. Biofeedback training leads to superior compliance to weight-bearing instructions compared with verbal instructions or training with a bathroom scale. Because partial weight-bearing instructions are commonly given to orthopedic patients, biofeedback training may be appropriately considered in any age group with similar effect.

A randomized trial comparing accelerated and traditional approaches to postoperative weightbearing rehabilitation after matrix-induced autologous chondrocyte implantation: findings at 5 years

BACKGROUND

While structured postoperative rehabilitation after matrix-induced autologous chondrocyte implantation (MACI) is considered critical, very little has been made available on how best to progressively increase weightbearing and exercise after surgery.

HYPOTHESIS

A significant improvement will exist in clinical and magnetic resonance imaging (MRI)-based scoring measures to 5 years after surgery. Furthermore, there will be no significant differences in outcomes in MACI patients at 5 years when comparing a traditional and an accelerated postoperative weightbearing regimen. Finally, patient demographics, cartilage defect parameters, and injury/surgery history will be associated with graft outcome.

STUDY DESIGN

Randomized controlled trial; level of evidence, 1.

METHODS

Clinical and radiological outcomes were studied in 70 patients who underwent MACI to the medial or lateral femoral condyle, in conjunction with either an "accelerated" or a "traditional" approach to postoperative weightbearing rehabilitation. Under the accelerated protocol, patients reached full weightbearing at 8 weeks after surgery, compared with 11 weeks for the traditional group. Clinical measures (knee injury and osteoarthritis outcome score [KOOS], short-form health survey [SF-36], visual analog scale [VAS], 6-minute walk test, and knee range of motion) were assessed before surgery and at 3, 6, 12, and 24 months and 5 years after surgery. High-resolution MRI was undertaken at 3, 12, and 24 months and 5 years after surgery and assessed 8 previously defined pertinent parameters of graft repair as well as a combined MRI composite score. The association between clinical and MRI-based outcomes, patient demographics, chondral defect parameters, and injury/surgery history was investigated.

RESULTS

Of the 70 patients recruited, 63 (31 accelerated, 32 traditional) underwent clinical follow-up at 5 years; 58 (29 accelerated, 29 traditional) also underwent radiological assessment. A significant time effect (P < .05) was demonstrated for all clinical and MRI-based scores over the 5-year period. While the VAS demonstrated significantly less frequent pain at 5 years in the accelerated group, there were no other significant differences between the 2 groups. Between 24 months and 5 years, a significant improvement (P < .05) in both groups was observed for the sport and recreation subscale of the KOOS as well as a significant decrease (P < .05) in active knee extension for the traditional group. There were no significant differences (P > .05) in the MRI-based scores between 24 months and 5 years after surgery. Patient age and defect size exhibited significant negative correlations (P < .05) with several MRI-based outcomes at 5 years, while there were no significant correlations (P > .05) between clinical and MRI-based outcomes. At 5 years after surgery, 94% and 95% were satisfied with the ability of MACI to relieve their knee pain and improve their ability to undertake daily activities, respectively.

CONCLUSION

The outcomes of this randomized trial demonstrate a safe and effective accelerated rehabilitation protocol as well as a regimen that provides comparable, if not superior, clinical outcomes to patients throughout the postoperative timeline.

Correlation of psychomotor findings and the ability to partially weight bear

Background

Partial weight bearing is thought to avoid excessive loading that may interfere with the healing process after surgery of the pelvis or the lower extremity. The object of this study was to investigate the relationship between the ability to partially weight bear and the patient's psychomotor skills and an additional evaluation of the possibility to predict this ability with a standardized psychomotor test.

Methods

50 patients with a prescribed partial weight bearing at a target load of 15 kg following surgery were verbally instructed by a physical therapist. After the instruction and sufficient training with the physical therapist vertical ground reaction forces using matrix insoles were measured while walking with forearm crutches. Additionally, psychomotor skills were tested with the Motorische Leistungsserie (MLS). To test for correlations Spearman's Rank correlation was used. For further comparison of the two groups a Mann-Withney test was performed using Bonferroni correction.

Results

The patient's age and body weight significantly correlated with the ability to partially weight bear at a 15 kg target load. There were significant correlations between several subtests of the MLS and ground reaction forces measured while walking with crutches. Patients that were able to correctly perform partial weight bearing showed significant better psychomotor skills especially for those subtests where both hands had to be coordinated simultaneously.

Conclusions

The ability to partially weight bear is associated with psychomotor skills. The MLS seems to be a tool that helps predicting the ability to keep within the prescribed load limits.

Is it possible to train patients to limit weight bearing on a lower extremity?

Orthopedic patients are often instructed on how much weight to bear on an injured or postoperative extremity. Although specific weight-bearing instructions are given to a majority of lower-extremity orthopedic patients, the ability of patients to comply with these instructions is questioned in the medical literature. This study compared the effectiveness of new forms of clinical interventions designed to train patients on weight bearing, focusing on the use of biofeedback devices designed to offer real-time feedback to partial weight-bearing patients. Twenty healthy patients aged 20 to 30 years completed 3 interventions: (1) verbal instructions on weight bearing, (2) training with a bathroom scale, and (3) training with a biofeedback device.Patients given touchdown weight-bearing instructions (25 lb) initially bore an average of 63.57±6.24 lb when given verbal instructions. This was reduced to 44.75±5.69 lb after training with a bathroom scale (P<.001), and was further reduced to 26.2±1.57 lb with biofeedback training (P=.011). Likewise, patients given partial weight-bearing instructions (75 lb) initially bore an average of 92.28±7.85 lb. No improvement occurred with the use of a bathroom scale (at 75 lb), which showed an average of 90.82±7.19 lb (P=1.000). Training with a biofeedback device improved the average weight bearing to 69.67±3.18 lb (P=.014).Biofeedback training led to superior compliance with touchdown and partial weight-bearing instructions. Because partial weight-bearing instructions are commonly given to orthopedic patients, training with such a device may be appropriately considered.

Inaccuracy of a physical strain trainer for the monitoring of partial weight bearing

OBJECTIVE

To investigate the use of a physical strain trainer for the monitoring of partial weight bearing.

DESIGN

Case series with healthy volunteers.

SETTING

Orthopedic clinic.

PARTICIPANTS

Healthy volunteers (N=10) with no history of foot complaints.

INTERVENTIONS

Volunteers were taught to limit weight bearing to 10% body weight (BW) and 50% BW, monitored by a physical strain trainer.

MAIN OUTCOME MEASURES

The parameters peak pressure, maximum force, force-time integral, and pressure-time integral were assessed by dynamic pedobarography when volunteers walked with full BW (condition 1), 50% BW (condition 2), and 10% BW (condition 3).

RESULTS

With 10% BW (condition 3), forces with normative gait (condition 1) were statistically significantly reduced under the hindfoot where the physical strain trainer is placed. All pedobarographic parameters were, however, exceeded when the total foot was measured. A limitation to 10% BW with the physical strain trainer (condition 3) was equal to a bisection of peak pressure and maximum force for the total foot with normative gait (condition 1). Halved BW (condition 2) left a remaining mean 82% of peak pressure and mean 59% of maximum force from full BW (condition 1).

CONCLUSIONS

The concept of controlling partial weight bearing with the hindfoot-addressing device does not represent complete foot loading. Such devices may be preferably applied in cases when the hindfoot in particular must be off-loaded. Other training devices (eg, biofeedback soles) that monitor forces of the total foot have to be used to control partial weight bearing of the lower limb accurately.

Radiological Assessment of Accelerated versus Traditional Approaches to Postoperative Rehabilitation following Matrix-Induced Autologous Chondrocyte Implantation

OBJECTIVE

To assess the safety and efficacy of accelerated compared with traditional postoperative weightbearing (WB) rehabilitation following matrix-induced autologous chondrocyte implantation (MACI) of the knee, using MRI.

METHODS

A randomized controlled study design was used to assess MRI-based outcomes of MACI grafts in 70 patients (45 men, 25 women) who underwent MACI to the medial or lateral femoral condyle, in combination with either traditional or accelerated approaches to postoperative WB rehabilitation. High-resolution MRI was undertaken and assessed 8 previously defined pertinent parameters of graft repair, as well as a combined MRI composite score at 3, 12, and 24 months postsurgery. The association between clinical and MRI-based outcomes, patient demographics, chondral defect parameters, and injury/surgery history was investigated.

RESULTS

Both groups significantly improved (P < 0.05) in the MRI composite score and pertinent descriptors of graft repair throughout the postoperative period until 24 months postsurgery. There were no differences (P > 0.05) observed between the 2 groups. Patient age, body mass index, chondral defect size, and duration of preoperative symptoms were significantly correlated (P < 0.05) with several MRI-based outcomes at 24 months, whereas there were no significant pertinent correlations (P > 0.05) observed between clinical and MRI-based outcomes.

CONCLUSION

The accelerated WB approach was not detrimental to graft development at any stage throughout the postoperative assessment timeline from baseline to 24 months postsurgery and may potentially accelerate patient return to normal function, while reducing postoperative muscle loss, intra-articular adhesions, and associated gait abnormalities.

Knee biomechanics during walking gait following matrix-induced autologous chondrocyte implantation

BACKGROUND

Matrix-induced autologous chondrocyte implantation is a technique for repairing articular cartilage defects in the knee. Despite reported improvements in pain, little is known about the recovery of knee biomechanics during walking gait.

METHODS

A randomized controlled study design was used to investigate knee biomechanics during gait in 61 patients following matrix-induced autologous chondrocyte implantation, in conjunction with either 'accelerated' or 'traditional' approaches to post-operative weight-bearing rehabilitation. Gait analysis was performed at 3, 6 and 12 months post-surgery in both patient groups, and two matched, unaffected control groups for comparison.

FINDINGS

The spatiotemporal and ground reaction force parameters were similar between patient groups and their respective control groups at all time points. When compared with controls, both patient groups demonstrated significantly reduced knee extension moments up until, and including, 12 months. The traditional group demonstrated a significantly reduced knee adduction moment at 3, 6 and 12 months, and a significantly reduced knee flexion moment at 3 months. There were no differences in these knee moments between the accelerated patient group and controls.

INTERPRETATION

Overall, a higher level of gait dysfunction was observed in patients who underwent traditional rehabilitation. Future research is needed to investigate the recovery of normal gait following matrix-induced autologous chondrocyte implantation, and its effect on repair tissue development.

Toe-touch weight bearing: myth or reality?

Toe-touch weight bearing and partial weight bearing are commonly prescribed orders. The purpose of this study is to evaluate the validity of toe-touch weight bearing and partial weight bearing regimens. Twenty-five orthopedic surgeons participated in the study. They were asked to answer a questionnaire regarding toe-touch weight bearing and partial weight bearing definitions, and were asked to bear weight partially according to the accepted definitions of each order. Weight bearing on the affected limb was measured by the SmartStep System (Andante Medical Devices, Ltd, Omer, Israel). There was a 40% success rate for toe-touch weight bearing as measured by kilograms and 58% as measured by percentage of body weight. There was a 22% success rate for partial weight bearing as measured by kilograms and 50% success rate as measured by percentage of body weight. For toe-touch weight bearing as measured by kilograms, 52% exerted a mean 15.9 kg more than the maximum. For partial weight bearing as measured by kilograms, 64% exerted too much weight with an average of 14.2 kg more than the maximum. There was a significantly higher success rate for the percentage of body weight order than the kilogram order. The partial weight bearing order with the percent body weight order had a lower mean deviation from desired performance. This study and others demonstrate the need for standardization of weight bearing orders.

The association between external-ground-reaction force and knee-joint kinetics during partial- and full-weight-bearing gait

BACKGROUND

Progressive weight-bearing is recommended following autologous chondrocyte implantation. This weight-bearing program assumes that increasing external loads experienced at the foot during gait are closely related to external-knee-joint moments. We investigated this relationship, and examined other variables that may contribute to knee-joint kinetics of which the clinician can modify using practical instruction within a clinical setting.

METHODS

Gait analysis was performed in 51 patients following autologous chondrocyte implantation, during various partial- and full-weight-bearing conditions. The contribution of ground-reaction force, kinematic and spatio-temporal gait parameters to external-knee moments was investigated within weight-bearing levels less than 60%, between 60% and 90% and more than 90% of individual body weight.

FINDINGS

There was no association between peak-ground-reaction force and the knee-adduction moment within the 60-90% and more than 90% weight-bearing conditions, nor the peak-knee-flexion moment at less than 60% weight-bearing. Peak-ground-reaction force accounted for no more than 21.4% and 18.6% of the variance in the knee-adduction and flexion moments, respectively, within any weight-bearing condition, while the combination of peak-ground-reaction force, kinematic and spatio-temporal parameters investigated accounted for no more than 39.7% and 52.2%, respectively. Foot-progression angle and knee-flexion during weight acceptance accounted for a significant (P<0.05) portion of the variance in external-knee moments, particularly at higher levels of weight-bearing.

INTERPRETATION

A large amount of variance in knee moments may be attributed to variables other than external loads, some of which can be modified by the clinician. Clinically, this is important for any therapist implementing progressive weight-bearing protocols.

A prospective study comparing attempted weight bearing in fiberglass below-knee casts and prefabricated pneumatic braces

Partial weight bearing is commonly advised after fracture of the lower extremity. Research has determined this to be inaccurate both in its instruction and its reproducibility. Many trauma departments are commonly using alternatives to plaster in the splintage of fractures, such as fiberglass and the prefabricated pneumatic braces. This study's null hypothesis is that there is no difference between partial weight bearing through a fiberglass cast as compared with a pneumatic walker. A prospective study was conducted in our department including all patients who had metatarsal or ankle fractures and could partially weight bear. Patients were excluded if they were not allowed to bear weight, had received operative fixation of their fracture, or were younger than age 16 years. The patients' total weight was measured first, and then they were trained to place 50% of their weight through the splinted limb. Three measurements were taken of their attempted weight bearing at 50%, and they were blinded to the results. Over a 16-month period, 117 patients were enrolled for this study: 72 in the pneumatic walker group and 45 in the fiberglass group. There was no significant difference in sex, age, or fracture type. There was a significant difference in percentage of weight placed through the splinted limb, with the pneumatic brace group placing much greater force than the fiberglass group. This may have been caused by altered proprioception from the walker. It is important to realize this when prescribing partial weight bearing in a particular splint as this may result in avoidable complications.

A biomechanical comparison of three different lateral tibia locking plates

The purpose of this study was to determine how well laterally placed modern tibia locking plates used in the treatment of Schatzker V tibial plateau fractures would uphold the medial plateau during axial loading. Fifteen third generation Sawbone tibias were obtained and an osteotomy was cut beneath the medial plateau to recreate Schatzker V type plateau fractures. Three groups were created (n=5 per group). Each group was plated with either a Synthes 4.5-mm LCP proximal tibial plate, a Zimmer NCB proximal tibia plate, or a DePuy Polyax tibial plate. A vertical load was applied over the medial plateau using an Instron servohydraulic test machine. Load measurements were analyzed at 2 and 3 mm of subsidence as well as load to failure. Failure was defined as closure of the wedge osteotomy or the medial condyle collapsing. A statistical difference was noted between the 2 plates from Synthes and DePuy and the plate from Zimmer with load carried at 2 and 3 mm of subsidence (Synthes 640.4 N & 943.7 N, Depuy 607.4 N & 891.0 N, Zimmer 459.7 N & 643.2 N). At failure, DePuy (2051.2 N) was statistically stronger than both Synthes (1724.8 N) and Zimmer (1724.8 N). The Synthes and DePuy plates both held up better than the Zimmer plate at 2 and 3 mm of subsidence. Despite this fact, all plates tested held up well above physiological forces of full and partial weight bearing and therefore would be appropriate for the treatment of Schatzker V type tibial plateau fractures.

An Inexpensive Weight Bearing Indicator With Load Range Capability for Rehabilitation of Patients With Lower Extremity Injuries

This paper investigates the mechanical behavior and design of a patent pending device called a load range weight bearing indicator (LWBI), which provides upper and lower range indication to patients with lower extremity injuries as part of a partial weight bearing rehabilitation. The LWBI consists of two opposing stacks (a.k.a. double stack) of snap domes—bistable mechanical elements that snap through only when a threshold weight is applied—sandwiched between a load transfer plate and base plate. The mechanical behavior of a LWBI has been characterized by testing single and double stacks of snap domes in a rigid aluminum fixture using a universal testing machine. Single stacks of two to eight snap domes each exhibited very predictable and repeatable buckling behavior (i.e., stack buckling load is simply the sum of individual snap dome buckling loads) when deflected at speeds typical for patients walking with a regular gait. The double stack configuration only works when supporting legs of the opposing snap dome stacks are offset by half the angle between adjacent legs. The lower load stack buckles first, while the higher load stack buckles at its threshold load because of the very low force required to keep the lower load stack collapsed. While the presence of a spacer has little effect on the double stack buckling behavior under controlled rate deflection in a precision test fixture, it was required for proper functioning of a LWBI prototype probably because of looser dimensional tolerances. The type of substrate that snap dome stacks are in contact with has little effect on the buckling loads as long as the material is not too soft. Finally, the speed of deflection within the expected range of ambulating patients has an insignificant effect on the LWBI’s buckling behavior. A LWBI prototype was designed based on the observed characteristics of the snap dome double stack with a spacer plate between the upper and lower load stacks. The prototype was installed in a recess in the insole of a biomechanical shoe beneath the patient’s heel. The shoe with LWBI was tested by various subjects pushing on a force plate and the upper and lower buckling loads were clearly indicated to the subject by audible and tactile click and measured as ground reaction force versus time. Future work will focus on further testing of the device and refinement of the design for various medical appliances.

An Inexpensive Weight Bearing Indicator Used for Rehabilitation of Patients With Lower Extremity Injuries

Background. Partial or nonweight bearing is a useful treatment prescribed by medical professionals (e.g., orthopedists, podiatrists) for patients rehabilitating from lower extremity injuries However, there is significant variability in patient conformance with the commonly used, but very imprecise “weight scale method.” Furthermore, the few commercially available load monitoring devices are rarely used because of their high cost. Method of Approach. As a simple and inexpensive alternative to current load monitoring methods and commercial products, a new medical device called a snap dome weight bearing indicator (WBI) has been developed to gently warn a patient when they have exceeded a limited percentage of their body weight on the recovering leg or foot. When installed in a patient’s shoe or medical appliance, the device does so by utilizing the reversible buckling phenomena of a snap dome to provide a tactile and audible feedback when the prescribed weight has been exceeded. To demonstrate the feasibility of this new device, the performance of (1) the snap dome by itself and (2) several WBI designs developed were tested. The most useful of the new designs include one incorporating a heel cup for loose fitting medical appliances and a podiatric off-loading indicator (POLI). In addition, a pilot study and manufacturing cost analysis of the POLI device were performed to investigate patient usability and affordability issues. Results. The particular four-leg snap domes used in device prototypes performed quite well with regards to buckling load consistency between domes, the linearity of buckling load by stacking domes in a parallel arrangement, and buckling load repeatability of a single dome. The performance of each WBI prototype was tested with regards to load transfer, tactile, and audible feedback to the patient, patient comfort, and ease of installation. Prototype performance was generally very good or excellent except for the POLI device, which does not provide sufficient tactile or audible feedback for many patients. A costing analysis of the POLI device suggests that it can be manufactured in the U.S. for around one dollar. Conclusions. The generally positive results from performance testing of commercially available snap domes and WBI prototypes suggest that this new medical device will indeed be an inexpensive, yet effective conformance tool for orthopedists and podiatrists to use in prescribing partial or no weight bearing for a patient.