Weight bearing after tibial fracture as a guide to healing

Employing machine learning to enhance fracture recovery insights through gait analysis

This study aimed to explore the potential of gait analysis coupled with supervised machine learning models as a predictive tool for assessing post-injury complications such as infection, malunion, or hardware irritation among individuals with lower extremity fractures. We prospectively identified participants with lower extremity fractures at a tertiary academic center. These participants underwent gait analysis with a chest-mounted inertial measurement unit device. Using customized software, the raw gait data were preprocessed, emphasizing 12 essential gait variables. The data were standardized, and several machine learning models, including XGBoost, logistic regression, support vector machine, LightGBM, and Random Forest, were trained, tested, and evaluated. Special attention was given to class imbalance, addressed using the synthetic minority oversampling technique (SMOTE). Additionally, we introduced a novel methodology to compute the post-injury recovery rate for gait variables, which operates independently of the time difference between the gait analyses of different participants. XGBoost was identified as the optimal model both before and after the application of SMOTE. Before using SMOTE, the model achieved an average test area under the ROC curve (AUC) of 0.90, with a 95% confidence interval (CI) of [0.79, 1.00], and an average test accuracy of 86%, with a 95% CI of [75%, 97%]. Through feature importance analysis, a pivotal role was attributed to the duration between the occurrence of the injury and the initial gait analysis. Data patterns over time revealed early aggressive physiological compensations, followed by stabilization phases, underscoring the importance of prompt gait analysis. χ2 analysis indicated a statistically significant higher readmission rate among participants with underlying medical conditions (p = 0.04). Although the complication rate was also higher in this group, the association did not reach statistical significance (p = 0.06), suggesting a more pronounced impact of medical conditions on readmission rates rather than on complications. This study highlights the transformative potential of integrating advanced machine learning techniques like XGBoost with gait analysis for orthopedic care. The findings underscore a shift toward a data-informed, proactive approach in orthopedics, enhancing patient outcomes through early detection and intervention. The χ2 analysis added crucial insights into the broader clinical implications, advocating for a comprehensive treatment strategy that accounts for the patient's overall health profile. The research paves the way for personalized, predictive medical care in orthopedics, emphasizing the importance of timely and tailored patient assessments.

Wireless Battery-free and Fully Implantable Organ Interfaces

Advances in soft materials, miniaturized electronics, sensors, stimulators, radios, and battery-free power supplies are resulting in a new generation of fully implantable organ interfaces that leverage volumetric reduction and soft mechanics by eliminating electrochemical power storage. This device class offers the ability to provide high-fidelity readouts of physiological processes, enables stimulation, and allows control over organs to realize new therapeutic and diagnostic paradigms. Driven by seamless integration with connected infrastructure, these devices enable personalized digital medicine. Key to advances are carefully designed material, electrophysical, electrochemical, and electromagnetic systems that form implantables with mechanical properties closely matched to the target organ to deliver functionality that supports high-fidelity sensors and stimulators. The elimination of electrochemical power supplies enables control over device operation, anywhere from acute, to lifetimes matching the target subject with physical dimensions that supports imperceptible operation. This review provides a comprehensive overview of the basic building blocks of battery-free organ interfaces and related topics such as implantation, delivery, sterilization, and user acceptance. State of the art examples categorized by organ system and an outlook of interconnection and advanced strategies for computation leveraging the consistent power influx to elevate functionality of this device class over current battery-powered strategies is highlighted.

Improved weight bearing during gait at 6 weeks post-surgery with an angle stable locking system after distal tibial fracture

BACKGROUND

Functional recovery after intramedullary nailing of distal tibial fractures can be monitored using ipsilateral vertical ground reaction forces (vGRF), giving insight into recovery of patients' gait symmetry. Previous work compared patient cohorts to healthy controls, but it remains unclear if these metrics can identify treatment-based differences in return to function post-surgery.

RESEARCH QUESTION

Is treatment of a distal tibial fracture with intramedullary nailing with an angle stable locking system (ASLS) associated with higher ipsilateral vGRF and improved symmetry compared to conventional intramedullary nailing at an early time point?

METHODS

Thirty-nine patients treated with ASLS intramedullary nailing were retrospectively compared to thirty-nine patients with conventional locking. vGRFs were collected at 1, 6, 12, 26, and 52 weeks post-surgery during standing and gait. Discrete metrics of ipsilateral vGRF (maximal force, impulse) and asymmetry were compared between treatments at each time point. Time-scale comparisons of ipsilateral vGRF and lower limb asymmetry were additionally performed for gait trials. Mann-Whitney Test or a two-way analysis of variance tested discrete comparisons; statistical non-parametric mapping tested time-scale data between treatment groups.

RESULTS

During gait, ASLS-treated patients applied more load on the operated limb (17-38% stance, p = 0.015) and consequently loaded limbs more symmetrically (8-37% stance, p = 0.008) during the loading response at 6 weeks post-surgery compared to conventional IM treatment. Discrete measures of symmetry at the same time point identified treatment-based differences in maximal force (p = 0.039) and impulse (p = 0.012), with ASLS-treated patients exhibiting more symmetry. No differences were identified in gait trials at later time points nor from all standing trials.

SIGNIFICANCE

During the initial loading response of gait, increased ipsilateral vGRF and improved weightbearing symmetry were identified in ASLS patients at 6 weeks post-surgery compared to conventional IM nailing. Early and objective metrics of dynamic movement are suggested to identify treatment-based differences in functional recovery.

A Wearable Biofeedback Device for Monitoring Tibial Load During Partial Weight-Bearing Walking

Patients with tibial fractures are usually advised to follow a partial weight-bearing gait rehabilitation program after surgery to promote bone healing and lower limb functional recovery. Currently, the biofeedback devices used for gait rehabilitation training in fracture patients use ground reaction force (GRF) as the indicator of tibial load. However, an increasing body of research has shown that monitoring GRF alone cannot objectively reflect the load on the lower limb bones during human movement. In this study, a novel biofeedback system was developed utilizing inertial measurement units and custom instrumented insoles. Based on the data collected from experiments, a hybrid approach combining a physics-based model and neural network architectures was used to predict tibial force. Compared to the traditional physics-based algorithm, the physical guided neural networks method showed better predictive performance. The study also found that regardless of the type of weight-bearing walking, the peak tibial force was significantly higher than the peak tibial GRF, and the time at which the peak tibial compression force occurs may not be consistent with the time at which the peak vertical GRF occurs. This further supports the idea that during gait rehabilitation training for patients with tibial fractures, monitoring and providing feedback on the actual tibial force rather than just the GRF is necessary. The developed device is a non-invasive and reliable portable device that can provide audio feedback, providing a viable solution for gait rehabilitation training outside laboratory and helping to optimize patients' rehabilitation treatment strategies.

Gait Analysis to Monitor Fracture Healing of the Lower Leg

Fracture healing is typically monitored by infrequent radiographs. Radiographs come at the cost of radiation exposure and reflect fracture healing with a time lag due to delayed fracture mineralization following increases in stiffness. Since union problems frequently occur after fractures, better and timelier methods to monitor the healing process are required. In this review, we provide an overview of the changes in gait parameters following lower leg fractures to investigate whether gait analysis can be used to monitor fracture healing. Studies assessing gait after lower leg fractures that were treated either surgically or conservatively were included. Spatiotemporal gait parameters, kinematics, kinetics, and pedography showed improvements in the gait pattern throughout the healing process of lower leg fractures. Especially gait speed and asymmetry measures have a high potential to monitor fracture healing. Pedographic measurements showed differences in gait between patients with and without union. No literature was available for other gait measures, but it is expected that further parameters reflect progress in bone healing. In conclusion, gait analysis seems to be a valuable tool for monitoring the healing process and predicting the occurrence of non-union of lower leg fractures.

Is a staged reloading protocol effective to time the removal of circular frames?

Aims

The timing of when to remove a circular frame is crucial; early removal results in refracture or deformity, while late removal increases the patient morbidity and delay in return to work. This study was designed to assess the effectiveness of a staged reloading protocol. We report the incidence of mechanical failure following both single-stage and two stage reloading protocols and analyze the associated risk factors.

Methods

We identified consecutive patients from our departmental database. Both trauma and elective cases were included, of all ages, frame types, and pathologies who underwent circular frame treatment. Our protocol is either a single-stage or two-stage process implemented by defunctioning the frame, in order to progressively increase the weightbearing load through the bone, and promote full loading prior to frame removal. Before progression, through the process we monitor patients for any increase in pain and assess radiographs for deformity or refracture.

Results

There were 244 frames (230 patients) included in the analyses, of which 90 were Ilizarov type frames and 154 were hexapods. There were 149 frames which underwent single-stage reloading and 95 frames which underwent a two-stage reloading protocol. Mechanical failure occurred after frame removal in 13 frames (5%), which suffered refracture. There were no cases of change in alignment. There was no difference between refracture patients who underwent single-stage or two-stage reloading protocols (p = 0.772). In all, 14 patients had failure prevented through identification with the reloading protocol.

Conclusion

Our reloading protocol is a simple and effective way to confirm the timing of frame removal and minimize the rate of mechanical failure. Similar failure rates occurred between patients undergoing single-stage and two-stage reloading protocols. If the surgeon is confident with clinical and radiological assessment, it may be possible to progress directly to stage two and decrease frame time and patient morbidity.

Cite this article: Bone Jt Open 2022;3(5):359–366.

Outcomes of early versus delayed weight-bearing with intramedullary nailing of tibial shaft fractures: a systematic review and meta-analysis

PURPOSE

Early weight bearing (EWB) is often recommended after intramedullary nailing of tibial shaft fractures, however, the risks and benefits have not been critically evaluated in a systematic review or meta-analysis. Therefore, the aims of this study were to perform a systematic review and meta-analysis comparing EWB and delayed weight-bearing (DWB) after intramedullary nailing of tibial shaft fractures and assess the relationship between weight-bearing, fracture union and healing.

METHOD

This review included studies comparing the effects of EWB, defined as weight-bearing before 6 weeks, and DWB on fracture union and healing. PubMed, Embase, CINAHL, and the Cochrane Library were searched from inception to 9 May 2021. Risk of bias was assessed using the Down's and Black Checklist and Cochrane Risk of Bias Tool 2.0. Data were synthesised in a meta-analysis, as well as narrative and tabular synthesis.

RESULTS

Eight studies were included for data extraction and meta-analysis. The analysis produced mixed results and found a significant decrease in mean union time (-2.41 weeks, 95% confidence interval: -4.77, -0.05) with EWB and a significant Odd's Ratio (OR) for complications with DWB (OR: 2.93, 95% CI: 1.40, 6.16). There was no significant difference in rates of delayed union, non-union, re-operation and malunion.

CONCLUSION

The included studies were of moderate risk of bias and demonstrated shorter union time and fewer complications with EWB. However, current evidence is minimal and has significant limitations. The role of EWB in high-risk patients is yet to be examined. Further well-designed, randomised studies are required on the topic.

Gait Alterations in Adults after Ankle Fracture: A Systematic Review

(1) Background: Ankle fracture results in pain, swelling, stiffness and strength reduction, leading to an altered biomechanical behavior of the joint during the gait cycle. Nevertheless, a common pattern of kinematic alterations has still not been defined. To this end, we analyzed the literature on instrumental gait assessment after ankle fracture, and its correlation with evaluator-based and patient-reported outcome measures. (2) Methods: We conducted a systematic search, according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines, of articles published from January 2000 to June 2021 in PubMed, Embase and PEDro on instrumental gait assessment after ankle fracture. (3) Results: Several changes in gait occur after ankle fracture, including a reduction in step length, swing time, single support time, stride length, cadence, speed and an earlier foot-off time in the affected side. Additionally, trunk movement symmetry (especially vertical) is significantly reduced after ankle fracture. The instrumental assessments correlate with different clinical outcome measures. (4) Conclusions: Instrumental gait assessment can provide an objective characterization of the gait alterations after ankle fracture. Such assessment is important not only in clinical practice to assess patients’ performance but also in clinical research as a reference point to evaluate existing or new rehabilitative interventions.

Vivaldi Antennas for Contactless Sensing of Implant Deflections and Stiffness for Orthopaedic Applications

The implementation of novel coaxial dipole antennas has been shown to be a satisfactory diagnostic platform for the prediction of orthopaedic bone fracture healing outcomes. These techniques require mechanical deflection of implanted metallic hardware (i.e., rods and plates), which, when loaded, produce measurable changes in the resonant frequency of the adjacent antenna. Despite promising initial results, the coiled coaxial antenna design is limited by large antenna sizes and nonlinearity in the resonant frequency data. The purpose of this study was to develop two Vivaldi antennas (a.k.a., "standard" and "miniaturized") to address these challenges. Antenna behaviors were first computationally modeled prior to prototype fabrication. In subsequent benchtop tests, metallic plate segments were displaced from the prototype antennas via precision linear actuator while measuring resultant change in resonant frequency. Close agreement was observed between computational and benchtop results, where antennas were highly sensitive to small displacements of the metallic hardware, with sensitivity decreasing nonlinearly with increasing distance. Greater sensitivity was observed for the miniaturized design for both stainless steel and titanium implants. Additionally, these data demonstrated that by taking resonant frequency data during implant displacement and then again during antenna displacement from the same sample, via linear actuators, that "antenna calibration procedures" could be used to enable a clinically relevant quantification of fracture stiffness from the raw resonant frequency data. These improvements mitigate diagnostic challenges associated with nonlinear resonant frequency response seen in previous antenna designs.

A Novel Capacitive Measurement Device for Longitudinal Monitoring of Bone Fracture Healing

The healing process of surgically-stabilised long bone fractures depends on two main factors: (a) the assessment of implant stability, and (b) the knowledge of bone callus stiffness. Currently, X-rays are the main diagnostic tool used for the assessment of bone fractures. However, they are considered unsafe, and the interpretation of the clinical results is highly subjective, depending on the clinician’s experience. Hence, there is the need for objective, non-invasive and repeatable methods to allow a longitudinal assessment of implant stability and bone callus stiffness. In this work, we propose a compact and scalable system, based on capacitive sensor technology, able to measure, quantitatively, the relative pins displacements in bone fractures treated with external fixators. The measurement device proved to be easily integrable with the external fixator pins. Smart arrangements of the sensor units were exploited to discriminate relative movements of the external pins in the 3D space with a resolution of 0.5 mm and 0.5°. The proposed capacitive technology was able to detect all of the expected movements of the external pins in the 3D space, providing information on implant stability and bone callus stiffness.

[Research on the nature of micromovement and the biomechanical staging of fracture healing]

Objective

To explore the nature of micromovement and the biomechanical staging of fracture healing.

Methods

Through literature review and theoretical analysis, the difference in micromovement research was taken as the breakthrough point to try to provide a new understanding of the role of micromovement and the mechanical working mode in the process of fracture healing.

Results

The process of fracture healing is the process of callus generation and connection. The micromovement is the key to start the growth of callus, and the total amount of callus should be matched with the size of the fracture space. The strain at the fracture end is the key to determine the callus connection. The strain that can be tolerated by different tissues in the fracture healing process will limit the micromovement. According to this, the fracture healing process can be divided into the initiation period, perfusion period, contradiction period, connection period, and physiological period, i.e., the biomechanical staging of fracture healing.

Conclusion

Biomechanical staging of fracture healing incorporates important mechanical parameters affecting fracture healing and introduces the concepts of time and space, which helps to understand the role of biomechanics, and its significance needs further clinical test and exploration.

The effect of housing environment on bone healing in a critical radius defect in New Zealand White rabbits

In animal studies on bone healing, the effect of housing space and physical activity are seldom taken into account. Bone formation was evaluated in New Zealand White rabbits (mean ± SEM BW: 3.9 ± 0.11 kg) with a critical bone defect after 12 weeks of rehabilitation in pair-housing in 3 m² large floor pens (Floor, n = 10) or standard single housing in 0.43 m² cages (Cage, n = 10). In the randomised full-factorial study, a bone replica of calcium phosphate cement (CPC, n = 10) or autologous bone (AB, n = 10) was implanted in the unilateral 20 mm radius defect. Post-mortem, the oxidative capacity was measured by citrate synthase (CS) activity in M. quadriceps and the defect filling volume and density evaluated by microcomputer tomography (μ-CT). Histology sections were evaluated by subjective scoring and histomorphometry. Fourteen rabbits remained until the end of the study. Group Floor (n = 7; 3 CPC + 4 AB) had a higher CS activity and a larger bone defect filling volume and lower density by μ-CT measurements than group Cage (n = 7; 3 CPC + 4 AB). Three out of four rabbits in AB-Floor presented fusion of the defect with reorganisation of trabecular bone, whereas three of four in AB-Cage showed areas of incomplete healing. Floor rabbits had a higher score of bony fusion between the radius and ulna than Cage rabbits. There were no differences between groups in histomorphometry. The study found that a larger housing space increased physical activity and promoted bone formation.

Bone Fracture Sensing Using Ultrasound Pitch-Catch Measurements: A Proof-of-Principle Study

The most common imaging method used to diagnose and monitor bone fractures and healing is multiple radiographic images performed by highly trained professionals with expensive equipment that can expose patients to high levels of ionizing radiation. Here we introduce and illustrate proof-of-concept of a potential alternative method for measuring bone fractures: ultrasound pitch-catch measurement technique. Measurements are performed with two piezoelectric transducers, housed in standard orthopedic screws and fixed on either side of simulated fractures, with and without an orthopedic plate, in ex vivo pig limb bones. Using this measurement method, we were able to detect significant differences between uncut and 2-, 5- and 10-mm-deep bone cuts using a two-sided t-test with an α level of 5%.

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.

Development of a step counting algorithm using the ambulatory tibia load analysis system for tibia fracture patients

Introduction: Ambulation can be used to monitor the healing of lower extremity fractures. However, the ambulatory behavior of tibia fracture patients remains unknown due to an inability to continuously quantify ambulation outside of the clinic. The goal of this study was to design and validate an algorithm to assess ambulation in tibia fracture patients using the ambulatory tibial load analysis system during recovery, outside of the clinic.

Center of pressure in a walking boot shifts posteriorly in patients following lower leg fracture

BACKGROUND

Studies have shown that the ambulatory behavior and amount of weight bearing performed by lower leg fracture patients, increases over time. It is likely that gait features, such as center of pressure (CoP), also change over time.

RESEARCH QUESTION

The purpose of this study was to characterize changes in CoP exhibited by lower leg fracture patients wearing a walking boot during the recovery period.

METHODS

Approximately 2 weeks post-surgery, seven lower leg fracture patients were fitted with a MaxTrax walking boot which was integrated with the Ambulatory Tibia Load Analysis System, an underfoot load monitoring system. Patients wore the walking boot for 2-12 weeks resulting in continuous load data during the recovery period. Ambulation was filtered from the raw data and daily average CoP values were calculated by averaging the CoP vectors from all steps in a given day.

RESULT

In general, the CoP vector varied in both the x and y directions during the initial stages of recovery but was more uniform during the later stages of healing. In 6/7 patients, the CoP in the y direction was closer to the forefoot during the initial stages of healing but shifted posteriorly as time post-surgery increased. The single patient that did not exhibit a posterior shift in CoP was also the only patient to develop a non-union. CoP in the x direction show a less clear trend. CoP in the x direction exhibited a medial shift in 5 patients and a lateral shift in 2 patients.

SIGNIFICANCE

During lower leg fracture recovery in a walking boot, the CoP in the y direction shifts posteriorly as time post-surgery increases and CoP monitoring may become a useful tool to monitor individual patient healing progression.

Delay in weight bearing in surgically treated tibial shaft fractures is associated with impaired healing: a cohort analysis of 166 tibial fractures

Background

The relation between timing of weight bearing after a fracture and the healing outcome is yet to be established, thereby limiting the implementation of a possibly beneficial effect for our patients. The current study was undertaken to determine the effect of timing of weight bearing after a surgically treated tibial shaft fracture.

Materials and methods

Surgically treated diaphyseal tibial fractures were retrospectively studied between 2007 and 2015. The timing of initial weight bearing (IWB) was analysed as a predictor for impaired healing in a multivariate regression.

Results

Totally, 166 diaphyseal tibial fractures were included, 86 cases with impaired healing and 80 with normal healing. The mean age was 38.7 years (range 16–89). The mean time until IWB was significantly shorter in the normal fracture healing group (2.6 vs 7.4 weeks, p < 0.001). Correlation analysis yielded four possible confounders: infection requiring surgical intervention, fracture type, fasciotomy and open fractures. Logistic regression identified IWB as an independent predictor for impaired healing with an odds ratio of 1.13 per week delay (95% CI 1.03–1.25).

Conclusions

Delay in initial weight bearing is independently associated with impaired fracture healing in surgically treated tibial shaft fractures. Unlike other factors such as fracture type or soft tissue condition, early resumption of weight bearing can be influenced by the treating physician and this factor therefore has a direct clinical relevance. This study indicates that early resumption of weight bearing should be the treatment goal in fracture fixation.

Level of evidence

3b.

Absolute or relative stability in minimal invasive plate osteosynthesis of simple distal meta or diaphyseal tibia fractures?

INTRODUCTION

Minimal invasive plate osteosynthesis in simple distal meta or diaphyseal tibia fractures can be applied using absolute (lag screw and neutralisation plate; LSN) or relative stability (bridge plate; BP). The primary aim of the study was to compare time to radiological union and time to full weight bearing in the two groups (LSN vs. BP). Reduction was performed either percutaneously or by a minimally open approach (mini open). Secondary aim was to analyse the number of complications between both groups.

METHODS

Retrospective single centre review of patients with a simple distal meta or diaphyseal tibia fracture operated with a Locking Compression Plate (LCP) between 2009 and 2015 in a Level one Trauma Centre. Postoperative radiographs were assessed in a standardised manner. Time to radiological fracture union and time to full weight bearing were observed. Callus index and postoperative complications were analysed.

RESULTS

Fifty-seven patients with a minimum follow-up of 6 months were analysed. Forty-eight patients had a shaft (AO/OTA Type 42) and nine a distal tibia fracture (AO/OTA Type 43). Forty patients were treated with using the LSN concept and 17 patients with the BP concept. Median time to radiological fracture union was statistically significant shorter (p=0.04) in the LSN group with 19 weeks compared to 27 weeks in the BP-group. Time to full weight bearing was 10 weeks in both groups. A total (including implant removal) of 35 reoperations were performed in the LSN-group and 18 in the BP-group. Wound healing disorders (deep surgical site infections) were seen less the LSN group in 3/40 (7.5%) compared to the BP-group with 3/17 (17.6%). In the LSN group, there was no statistical difference in time to union or weight bearing between a percutaneous or mini open approach.

CONCLUSION

Stable osteosynthesis of simple distal meta or diaphyseal tibia fractures leads to faster radiologic fracture healing without an increase in complications or number of revisions compared to bridge plating. If a percutaneous reduction is not feasible for the insertion of a lag screw, a mini-open approach does not lead to a delay in fracture healing.

Does weight-bearing assignment after intramedullary nail placement alter healing of tibial shaft fractures?

INTRODUCTION

There is no consensus regarding postoperative weight-bearing (WB) assignment after treatment of tibial shaft fractures with an intramedullary nail. This study aims to determine if the postoperative WB assignment after tibia intramedullary nail placement alters healing.

METHODS

Closed AO type 42A fractures treated with a reamed statically-locked intramedullary nail over a 10-year period were retrospectively reviewed from injury at 2, 3, 6, 9 and 12 month intervals until union or revision. Patients were categorized according to postoperative weight-bearing assignment: weight-bearing-as-tolerated (WBAT) or non-weight-bearing (NWB). Patients with additional diagnoses that confound routine fracture healing were excluded. Postoperative radiographic union scores for tibial fractures (RUST), coronal/sagittal angulations, and length were compared between different weight-bearing groups. Union was defined as a RUST≥10 at a painless fracture site.

RESULTS

A total of 83 patients achieved union (32 WBAT, 51 NWB). Both WB groups had similar preoperative demographics. Average age was 37±13 years and follow-up averaged 1.3±0.2 years. There were no significant differences in average time to radiographic union between NWB versus WBAT groups (5.5 vs. 6.1 months, respectively; P=0.208) nor radiographic healing at 2, 3, and 6-month intervals (P=0.631). There were two nonunions and one fracture shortened in the NWB group. There were no reoperations for symptomatic or broken hardware in either cohort.

CONCLUSION

Immediate WBAT after statically-locked intramedullary nail placement in simple tibial shaft fractures does not alter the time until or course of radiographic union.

LEVEL OF EVIDENCE

IV.

The radiographic union scale in tibial (RUST) fractures: Reliability of the outcome measure at an independent centre

Objectives

The radiographic union score for tibial (RUST) fractures was developed by Whelan et al to assess the healing of tibial fractures following intramedullary nailing. In the current study, the repeatability and reliability of the RUST score was evaluated in an independent centre (a) using the original description, (b) after further interpretation of the description of the score, and (c) with the immediate post-operative radiograph available for comparison.

Methods

A total of 15 radiographs of tibial shaft fractures treated by intramedullary nailing (IM) were scored by three observers using the RUST system. Following discussion on how the criteria of the RUST system should be implemented, 45 sets (i.e. AP and lateral) of radiographs of IM nailed tibial fractures were scored by five observers. Finally, these 45 sets of radiographs were rescored with the baseline post-operative radiograph available for comparison.

Results

The initial intraclass correlation (ICC) on the first 15 sets of radiographs was 0.67 (95% CI 0.63 to 0.71). However, the original description was being interpreted in different ways. After agreeing on the interpretation, the ICC on the second cohort improved to 0.75. The ICC improved even further to 0.79, when the baseline post-operative radiographs were available for comparison.

Conclusion

This study demonstrates that the RUST scoring system is a reliable and repeatable outcome measure for assessing tibial fracture healing. Further improvement in the reliability of the scoring system can be obtained if the radiographs are compared with the baseline post-operative radiographs.

Cite this article: Mr J.M. Leow. The radiographic union scale in tibial (RUST) fractures: Reliability of the outcome measure at an independent centre. Bone Joint Res 2016;5:116–121. DOI: 10.1302/2046-3758.54.2000628.

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.

Monitoring Healing Progression and Characterizing the Mechanical Environment in Preclinical Models for Bone Tissue Engineering

The treatment of large segmental bone defects remains a significant clinical challenge. Due to limitations surrounding the use of bone grafts, tissue-engineered constructs for the repair of large bone defects could offer an alternative. Before translation of any newly developed tissue engineering (TE) approach to the clinic, efficacy of the treatment must be shown in a validated preclinical large animal model. Currently, biomechanical testing, histology, and microcomputed tomography are performed to assess the quality and quantity of the regenerated bone. However, in vivo monitoring of the progression of healing is seldom performed, which could reveal important information regarding time to restoration of mechanical function and acceleration of regeneration. Furthermore, since the mechanical environment is known to influence bone regeneration, and limb loading of the animals can poorly be controlled, characterizing activity and load history could provide the ability to explain variability in the acquired data sets and potentially outliers based on abnormal loading. Many approaches have been devised to monitor the progression of healing and characterize the mechanical environment in fracture healing studies. In this article, we review previous methods and share results of recent work of our group toward developing and implementing a comprehensive biomechanical monitoring system to study bone regeneration in preclinical TE studies.

Experimental model for controlling shear using the Ilizarov frame

OBJECTIVE

This study has been designed to ascertain whether a standard configuration Ilizarov tibial frame can control shear motion at the fracture site of an oblique fracture within acceptable limits for axial micro-motion, and therefore promote bony union. If not, are there simple modifications to the frame design that can achieve this?

METHODS

Four Ilizarov frame designs were tested on a load test rig. Fracture site shear displacement was measured using a clip gauge attached to an automated data recording system.

FINDINGS

The standard Ilizarov frame allowed 4mm of fracture site displacement at 340N of load. Our fourth frame design, the locked olive frame, allowed a maximum of 0.61mm displacement at 700N.

INTERPRETATION

This is one of only two studies to look at circular frame fracture site control in oblique fractures. This is the only study to characterise Ilizarov frame stiffness in oblique fractures. We have shown that the standard Ilizarov frame design is inadequate for control of oblique fractures in this mechanical model. Our data show that with the application of simple principles, the Ilizarov frame can be modified to provide better fracture site control. These frame designs can be applied clinically to reduce fracture site shear motion in oblique fractures, resulting in improved union rates.

Fracture healing redefined

It is well established that local mechanical conditions and interfragmentary movement are important factors for successful bone healing and may vary dramatically with patient fracture-load and activity. Up until now however it was technically impossible to use these key influence parameters in the aftercare treatment process of human lower extremity fractures. We propose a theory that with state of the art sensor technology these biomechanical influences can not only be monitored in vivo, but also used for individualized therapy protocols. Local measurement systems for fracture healing are available but remain research tools, due to various technical issues. To investigate the biomechanical influences on healing right away surrogate sensor tools are needed. Various gait characteristics have been proposed as surrogate measures. Currently available sensor tools could be modified with the appropriate support structure to allow such measurements continuously over the course of a fracture healing. Interdisciplinary work between clinicians, software engineers with computer and biomechanical simulations is needed. Through such a sensor system human boundary conditions for fracture healing could not only be defined for the first time, but also used for a unique, extendible aftercare system. With this tool critical healing situations would be detected much earlier and could be prevented with easy activity modifications, reducing patient and socioeconomic burden of disease. The hypothesis, necessary tools and support structures are presented.

Peak loading during walking is not associated with fracture migration following tibial plateau fracture: A preliminary case series

Tibial plateau fractures are common, but little evidence exists for their postoperative management, especially when recommending if patients should weight bear at all, partially, or as tolerated. In this study, we describe the loads passing through the fracture construct and the associated fracture migration over the first year following surgery. Nine patients were treated with open reduction and internal fixation and instructed to weight bear as tolerated. Fracture loading and migration were assessed at 2, 12, 26, and 52 weeks postoperative. Fracture loading was calculated as the knee joint reaction force (peak, average, the angle of the force vector, and the point of force application) using gait analysis and an inverse dynamics musculoskeletal model. Fracture migration was assessed using radiostereometric analysis. The fractures were progressively loaded during the rehabilitation phase. The point of application of the load shifted from neutral to medial by week 26 for all patients. Migration during the first postoperative year was within current clinical acceptable limits. The peak load during walking at each time point was not associated with fracture fragment migration and does not appear to exceed the elastic limit of the fracture construct.

Static or dynamic intramedullary nailing of femur and tibia

Introduction:

The basic principle of non-surgical fracture treatment is to restore the original anatomical position of fractured fragments by different techniques, without direct access to the bone and without further traumatizing of tissues. Intramedullary nailing is synthesis and consolidation of fracture fragments with the main goal to gain strength and permanent placement of the implants. Two techniques of intramedullary osteosynthesis are used: with dynamic or with static intramedullary nail. Dynamization include conversion of static nail by removing screws from the longest fragment.

Aim:

The aim of this study is to determine whether there is a difference in the speed and quality of healing of the type A and B fractures of the femur and tibia treated by static or dynamic intramedullary nails and to compare the results.

Material and methods:

The study was conducted at the Clinic for Orthopaedics and Traumatology, Clinical Center University Sarajevo from January 2004 to June 2009. The study was retrospective-prospective, manipulative, controlled and it was conducted on a total of 129 patients with closed fractures of the diaphysis of the femur and tibia type A and type B, with different segments of bone, regardless of sex and age structure, with the exception of children under 14 years of age.

Results:

Precisely there were 47 patients with femoral fractures and 82 patients with tibial fractures. The average number of weeks of healing femoral and tibial fractures was slightly in advantage of static intramedullary osteosynthesis, it was 17.08 weeks (SD=3.382). The average number of weeks of healing in 23 patients with fractures of the femur, treated by dynamic intramedullary osteosynthesis was 17.83 (SD=2.978). We can conclude that static intramedullary nailing osteosynthesis unable movements between fragments which directly stimulates bone formation and formation of minimal callus.

Conclusion:

Static intramedullary osteosynthesis resolve the problem of stabilizing the fracture, limb shortening and rotation of fragments.

Evaluation of the effectiveness of the angular stable locking system in patients with distal tibial fractures treated with intramedullary nailing: a multicenter randomized controlled trial

BACKGROUND

Angular stable locking of intramedullary nails has been shown to enhance fixation stability of tibial fractures in biomechanical and animal studies. The aim of our study was to assess whether use of the angular stable locking system or conventional locking resulted in earlier full weight-bearing with minimum pain for patients with a distal tibial fracture treated with an intramedullary nail.

METHODS

A prospective multicenter, randomized, patient-blinded trial was conducted with adults who had a distal tibial fracture. Patients' fractures were managed with an intramedullary nail locked with either an angular stable locking system or conventional locking screws. Outcomes were evaluated at six weeks, twelve weeks, six months, and one year after surgery. Time to full weight-bearing with minimum pain was calculated with use of daily entries from patient diaries. Secondary outcomes included pain at the fracture site under load, quality of life, gait analysis, mobility, radiographic findings, and adverse events.

RESULTS

One hundred and forty-two patients were randomly allocated to two treatment groups: seventy-five to the group receiving intramedullary nailing with the angular stable locking system and sixty-seven to the group receiving conventional intramedullary nailing. No clinically important differences were found for either the primary or secondary outcome parameters between the groups during the entire follow-up period.

CONCLUSIONS

Use of an angular stable locking system with intramedullary nailing did not improve the outcome compared with conventional locking screws in the treatment of distal tibial fractures.

Current Options for Determining Fracture Union

Determining whether a bone fracture is healed is one of the most important and fundamental clinical determinations made in orthopaedics. However, there are currently no standardized methods of assessing fracture union, which in turn has created significant disagreement among orthopaedic surgeons in both clinical and research settings. An extensive amount of research has been dedicated to finding novel and reliable ways of determining healing with some promising results. Recent advancements in imaging techniques and introduction of new radiographic scores have helped decrease the amount of disagreement on this topic among physicians. The knowledge gained from biomechanical studies of bone healing has helped us refine our tools and create more efficient and practical research instruments. Additionally, a deeper understanding of the molecular pathways involved in the bone healing process has led to emergence of serologic markers as possible candidates in assessment of fracture union. In addition to our current physician centered methods, patient-centered approaches assessing quality of life and function are gaining popularity in assessment of fracture union. Despite these advances, assessment of union remains an imperfect practice in the clinical setting. Therefore, clinicians need to draw on multiple modalities that directly and indirectly measure or correlate with bone healing when counseling patients.

Ilizarov external fixation or locked intramedullary nailing in diaphyseal tibial fractures: a randomized, prospective study of 58 consecutive patients

PURPOSE

The aim of this study was to compare the Ilizarov circular fixator (IL) and locked intramedullary nailing (IM).

PATIENTS AND METHODS

Patients with isolated tibia shaft fractures were randomly allocated to either the IL (n = 31) or IM (n = 27) method. Conventional radiographs, postoperative pain assessment, self-appraisal scores and complications were evaluated. At the clinical 1-year follow-up, the patients were also evaluated by an independent observer.

RESULTS

The minority of patients had open fractures, two and nine patients in the IM and IL groups, respectively. Eight patients in the IM group and four in the IL group sustained major complications (p = 0.107). In the IM group, two patients developed compartment syndrome, one deep infection, one hardware failure, one delayed union, one pseudarthrosis and two had a malunion. In the IL group, two patients developed pseudarthrosis and two had a malunion. Superficial pin-site infections were observed in 16 patients in the IL group. The fractures had healed radiographically at 12 weeks in both groups. At the 1-year follow-up, there were differences in pain (VAS) and satisfaction (VAS) scores in favor of IL treatment (VAS, p = 0.03 and p = 0.02, respectively). There were no differences between the groups with regard to range of motion (ROM) in the knee and ankle joints. The registration of local tenderness and pain revealed that there were 19 patients with anterior knee pain in the IM group and one in the IL group at the 1-year follow-up (p < 0.001).

CONCLUSION

The IL is a safe and reliable alternative to IM for the treatment of tibial shaft fractures, with a low complication rate and good clinical outcome. Both treatments were well tolerated, but at the 1-year follow-up the patients in the IM group had more pain and were less satisfied. Finally, there was a high frequency of anterior knee pain in the IM group.

Clinical Implications of Changing Parameters on an Elliptical Trainer

BACKGROUND

Specific weightbearing instructions continue to be a part of routine orthopaedic clinical practice on an injured or postoperative extremity. Researchers and clinicians have struggled to define the best weightbearing strategies to maximize clinical outcomes.

PURPOSE

To investigate the average percentage body weight (APBW) values, weightbearing distribution percentages (WBDP), and cadence values on the entire foot, hindfoot, and forefoot during changing resistance and incline on an elliptical trainer, as well as to suggest clinical implications.

STUDY DESIGN

Descriptive laboratory study.

METHODS

An original research study was performed consisting of 30 asymptomatic subjects (mean age, 29.54 ± 12.64 years; range, 21-69 years). The protocol included 3 consecutive tests of changing resistance and incline within a speed range of 70 to 95 steps/min. The SmartStep weightbearing gait analysis system was utilized to measure the values.

RESULTS

The APBW values for the entire foot ranged between 70% and 81%, the hindfoot values were between 27% and 57%, and the forefoot values between 42% and 70%. With regard to WBDP, the forefoot remained planted on the pedal (stance phase) 2 to 3 times more as compared with the hindfoot raise in the swing phase.

CONCLUSION

The study findings highlight the fact that elliptical training significantly reduces weightbearing in the hindfoot, forefoot, and entire foot even at higher levels of resistance and incline.

CLINICAL RELEVANCE

Weightbearing on the hindfoot consistently displayed the lowest weightbearing values. Orthopaedic surgeons, now equipped with accurate weightbearing data, may recommend using the elliptical trainer as a weightbearing exercise early on following certain bony or soft tissue pathologies and lower limb surgical procedures.

Biomechanical methods for the assessment of fracture repair

The progress of fracture healing is directly related to an increasing stiffness and strength of the healing fracture. Similarly the weight bearing capacity of a bone directly relates to the mechanical stability of the fracture. Therefore, assessing the progress of fracture repair can be based on the measurement of the mechanical stability of the healing fracture. However, fracture stability is difficult to assess directly due to various obstacles of which shielding of the mechanical properties by the fracture fixation construct is the most relevant one. Several assessment methods have been proposed to overcome these obstacles and to obtain some sort of mechanical surrogate describing the stability of the fracture. The most direct method is the measurement of the flexibility of a fracture under a given external load, which comprises the challenge of accurately measuring the deformation of the bone. Alternative approaches include the measurement of load share between implant and bone by internal or by external sensors. A direct 3 dimensional measurement of bone displacement is provided by radiostereometric analysis which can assess fracture migration and can detect fracture movement under load. More indirect mechanical methods induce cyclic perturbations within the bone and measure the response as a function of healing time. At lower frequencies the perturbations are induced in the form of vibration and at higher frequencies in the form of ultrasonic waves. Both methods provide surrogates for the mechanical properties at the fracture site. Although biomechanical properties of a healing fracture provide a direct and clinically relevant measure for fracture healing, their application will in the near future be limited to clinical studies or research settings.

Development and preliminary validation of a Function IndeX for Trauma (FIX-IT)

BACKGROUND

Assessing fracture healing in clinical trials is subjective. The new Function IndeX for Trauma (FIX-IT) score provides a simple, standardized approach to assess weight-bearing and pain in patients with lower extremity fractures. We conducted an initial validation of the FIX-IT score.

METHODS

We conducted a cross-sectional study involving 50 patients with lower extremity fractures across different stages of healing to evaluate the reliability and preliminary validity of the FIX-IT score. Patients were independently examined by 2 orthopedic surgeons, 1 orthopedic fellow, 2 orthopedic residents and 2 research coordinators. Patients also completed the Short Form-36 version 2 (SF-36v2) questionnaire, and convergent validity was tested with the SF-36v2.

RESULTS

For interrater reliability, the intraclass correlation coefficients ranged from 0.637 to 0.915. The overall interrater reliability for the total FIX-IT score was 0.879 (95% confidence interval 0.828-0.921). The correlations between the FIX-IT score and the SF-36 ranged from 0.682 to 0.770 for the physical component summary score, from 0.681 to 0.758 for the physical function subscale, and from 0.677 to 0.786 for the role-physical subscale.

CONCLUSION

The FIX-IT score had high interrater agreement across multiple examiners. Moreover, FIX-IT scores correlate with the physical scores of the SF-36. Although additional research is needed to fully validate FIX-IT, our results suggest the potential for FIX-IT to be a reliable adjunctive clinician measure to evaluate healing in lower extremity fractures.

LEVEL OF EVIDENCE

Diagnostic Study Level I.

Weight bearing after a periarticular fracture: what is the evidence?

Orthopedic surgeons frequently provide weight-bearing recommendations to guide patient recovery following lower extremity fractures. This article discusses the available literature regarding the effects of early weight bearing on fracture healing, patient compliance with weight bearing restrictions, and the effect of different weight bearing protocols following acetabular, tibial plateau, tibial plafond, ankle, and calcaneus fractures.

Advances and future directions for management of trauma patients with musculoskeletal injuries

Musculoskeletal injuries are the most common reason for operative procedures in severely injured patients and are major determinants of functional outcomes. In this paper, we summarise advances and future directions for management of multiply injured patients with major musculoskeletal trauma. Improved understanding of fracture healing has created new possibilities for management of particularly challenging problems, such as delayed union and non union of fractures and large bone defects. Optimum timing of major orthopaedic interventions is guided by increased knowledge about the immune response after injury. Individual treatment should be guided by trading off the benefits of early definitive skeletal stabilisation, and the potentially life-threatening risks of systemic complications such as fat embolism, acute lung injury, and multiple organ failure. New methods for measurement of fracture healing and function and quality of life outcomes pave the way for landmark trials that will guide the future management of musculoskeletal injuries.

Validation of a standardised gait score to predict the healing of tibial fractures

There is no absolute method of evaluating healing of a fracture of the tibial shaft. In this study we sought to validate a new clinical method based on the systematic observation of gait, first by assessing the degree of agreement between three independent observers regarding the gait score for a given patient, and secondly by determining how such a score might predict healing of a fracture.

We used a method of evaluating gait to assess 33 patients (29 men and four women, with a mean age of 29 years (15 to 62)) who had sustained an isolated fracture of the tibial shaft and had been treated with a locked intramedullary nail. There were 15 closed and 18 open fractures (three Gustilo and Anderson grade I, seven grade II, seven grade IIIA and one grade IIIB). Assessment was carried out three and six months post-operatively using videos taken with a digital camera. Gait was graded on a scale ranging from 1 (extreme difficulty) to 4 (normal gait). Bivariate analysis included analysis of variance to determine whether the gait score statistically correlated with previously validated and standardised scores of clinical status and radiological evidence of union.

An association was found between the pattern of gait and all the other variables. Improvement in gait was associated with the absence of pain on weight-bearing, reduced tenderness over the fracture, a higher Radiographic Union Scale in Tibial Fractures score, and improved functional status, measured using the Brazilian version of the Short Musculoskeletal Function Assessment questionnaire (all p < 0.001). Although further study is needed, the analysis of gait in this way may prove to be a useful clinical tool.

A novel intramedullary nail for micromotion stimulation of tibial fractures

BACKGROUND

Animal studies and clinical trials have suggested that early application of controlled axial micromotion can accelerate healing of long bone fractures compared to rigid fixation. However, experimental investigations of micromotion constructs have been limited to external fixators, which have a higher incidence of complications than intramedullary nails. The purpose of this study was to assess whether a novel intramedullary nail design can generate stimulatory micromotion under minimal weight-bearing loads typical of the early healing period.

METHODS

Eight cadaver tibiae were reamed, osteotomised, and implanted with commercially-available IM nails fitted with a custom insert that allowed 1mm of axial micromotion after proximal/distal interlocking. Specimens were mounted in a materials testing machine and subjected to cyclic axial loading while interfragmentary motion was measured using an extensometer. Implants were also tested in standard statically-locked mode.

FINDINGS

The average force required to cause distraction of the fracture gap in micromotion mode was 37.0 (SD 21.7) N. The mean construct stiffness was 1046.8 (SD 193.6) N/mm in static locking mode and 512.4 (SD 99.6) N/mm in micromotion mode (significantly different, P<0.001).

INTERPRETATION

These results support the development of a micromotion-enabled IM nail because the forces required to cause interfragmentary movements are very low, less than the weight of the hanging shank and foot. In contrast to rigid-fixation nails, which require significant weight-bearing to induce interfragmentary motion, the micromotion-enabled nail may allow movement in non-weight-bearing patients during the early healing period when the benefits of mechanical stimulation are most critical.

Simulation of fracture healing in the tibia: mechanoregulation of cell activity using a lattice modeling approach

In this study, a three-dimensional (3D) computational simulation of bone regeneration was performed in a human tibia under realistic muscle loading. The simulation was achieved using a discrete lattice modeling approach combined with a mechanoregulation algorithm to describe the cellular processes involved in the healing process-namely proliferation, migration, apoptosis, and differentiation of cells. The main phases of fracture healing were predicted by the simulation, including the bone resorption phase, and there was a qualitative agreement between the temporal changes in interfragmentary strain and bending stiffness by comparison to experimental data and clinical results. Bone healing was simulated beyond the reparative phase by modeling the transition of woven bone into lamellar bone. Because the simulation has been shown to work with realistic anatomical 3D geometry and muscle loading, it demonstrates the potential of simulation tools for patient-specific pre-operative treatment planning.

Guidelines for fracture healing assessments in clinical trials. Part I: definitions and endpoint committees

Patients sustaining long bone fractures experience a significant socioeconomic burden. Investigational products are in developmental phases in an attempt to significantly reduce the time to fracture healing, however, high quality clinical trials need to be conducted in order to evaluate the efficacy of these interventions. The assessment of fracture healing is not a standardised process as it involves a degree of subjectivity. The use of endpoint Adjudication Committees to adjudicate fracture healing in clinical trials has the potential to help to resolve this issue. This manuscript outlines the current definitions used in the assessment of fracture healing and highlights the need for endpoint Adjudication Committees in fracture healing trials.

Opening-wedge high tibial osteotomy with and without bone graft

Medial opening-wedge has gained popularity in comparison to other techniques of high tibial osteotomy. This technique involves the creation of a gap in the tibia. Filling the gap with autologous iliac bone graft was recommended in the classic description, to prevent complications such as correction loss or delayed bone union. No previous reports have compared grafted and nongrafted osteotomies. This study hypothesized that the use of autologous bone graft in medial opening-wedge high tibial osteotomy (MOWHTO) less than 12.5 mm is unnecessary. A prospective randomized clinical trial was conducted. Forty-six opening-wedge high tibial osteotomies were carried out between April 2007 and December 2008. All had fixation with a type of Puddu stainless steel plate and screws. Patients were randomly divided by software analysis into two groups: group A had osteotomies that were filled with autologous bone graft and group B had osteotomies that were unfilled. Autologous iliac bone graft was harvested in both groups. Clinical and radiographic evaluations were performed twice monthly by blinded investigators. The rates of complications were compared between the groups. There was no difference in demographic data. Mean time to clinical bone union in group A was 12.4 weeks (confidence interval [CI] 11.2-13.6) and in group B was 13.7 weeks (CI 12.5-14.9), but this difference was not significant (P = 0.13). Signals of correction loss occurred in one patient (4.35%) in group A, and in two patients (8.70%) in group B. All osteotomies had achieved bone union. It was concluded that time to bone union was not statistically different between the group with bone graft and the group without graft.

Outcomes assessment in fracture healing trials: a primer

The measurement of clinical outcomes in trauma research is often problematic in that it is subjective and currently no feasible gold standard evaluation is available. Consequently, observed trial results are partly dependent on which outcome measure is used. Precise and useful estimates of treatment effects can only be obtained when using reliable, valid, and responsive instruments for measuring fracture healing. This overview outlines the concept of the validation of outcome measures and provides a summary of available and frequently used instruments in orthopaedic clinical trials. Outcome instruments can be divided into assessments by the clinician and assessments by the patient. Clinician-assessed measures are frequently used in routine practice but have often not been validated before their use in research. They include clinical and radiographic assessments. In contrast, patient-assessed measures have been designed specifically for investigational purposes and measure health on various domains. Some of them have been validated extensively. Critically evaluating established clinician-based assessments and integrating those found to be valid with patient-assessed outcomes into a composite measure of fracture healing constitute major future challenges.

When is a fracture healed? Radiographic and clinical criteria revisited

Selecting the most appropriate outcome measures can be especially burdensome in trials studying fracture healing, because the process of fracture healing is subjective and without a gold standard. Although a wide variety of radiographic modalities are available, plain radiography remains the most common approach for healing assessment. Radiographic criteria, however, do not correlate well with fracture strength and stiffness. Additional challenges include a lack of consensus in what radiographic measures are most appropriate in the assessment of healing. In this article, we provide an overview of the most commonly used radiographic and clinical criteria for defining fracture healing. The validity and reliability of alternative approaches is also discussed.

Quantification of fracture healing from radiographs using the maximum callus index

Callus formation and growth are an essential part of secondary fracture healing. Callus growth can be observed radiographically and measured using the "Callus Index," which is defined as the maximum diameter of the callus divided by the diameter of the bone. We compared three groups of patients with tibial fractures treated by external fixation, intramedullary nailing, and casting to assess the validity of using serial measurements of callus index as a measure of fracture healing. When callus index was plotted against time for each patient, the point at which the fracture began to remodel, indicated by the highest point of the curve, was observed as a consistent feature regardless of fixation method. This occurred on average at 2(1/2) weeks after plaster cast removal (14 weeks post injury), 5 weeks after external fixator removal (22 weeks post injury), and 27 weeks post injury for the intramedullary nailed fractures. Because remodeling only occurs once the fracture is stable, a peak in callus index is a reliable sign that the fracture has united. Serial measurements of callus index would therefore appear to offer a simple method of quantifying secondary fracture healing regardless of the treatment method used.

LEVEL OF EVIDENCE

Level III, diagnostic study. See Guidelines for Authors for a complete description of levels of evidence.