Application of the Radiographic Union Scale for Tibial fractures (RUST): Assessment of healing rate and time of tibial fractures managed with intramedullary nailing

Knee Injury and Osteoarthritis Outcome Score for Tibial Shaft Fractures: Validity, Reliability, Responsiveness, and Minimal Clinically Important Difference

BACKGROUND

This study evaluated the relevance, construct validity, test-retest reliability, and responsiveness and estimate the minimal clinically important difference in the Knee Injury Osteoarthritis outcome score (KOOS) for patients with tibial shaft fractures.

MATERIALS AND METHODS

This prospective cohort study included adult patients who were surgically treated after tibial shaft fracture (AO 42-). The primary outcome measure was the score on the KOOS subscales of pain, symptoms, activities of daily living, sport and recreational activities, and knee-related quality of life. Scores were obtained at 14 days, 15 days, 6 weeks, and 3, 6, and 12 months postoperatively. Relevance was evaluated by patients' ranking all KOOS items; construct validity was evaluated by comparing KOOS scores with the Health-Related Quality of Life questionnaire; test-retest reliability was evaluated by comparing KOOS scores over a 24-hour period; and responsiveness was evaluated based on predefined hypotheses and effect size.

RESULTS

Sixty patients (mean age, 47.1 years; range, 18-84 years) were included. Results showed acceptable relevance and construct validity for all KOOS subscales. Test-retest reliability was high for all 5 subscales, with an intraclass correlation coefficient of 0.9. Responsiveness was observed with moderate to high correlations (r≥0.3) for the predefined hypotheses and moderate to large effect sizes, ranging from 0.5 to 1.3, for the subscales of pain, activities of daily living, symptoms, and sport and recreational activities.

CONCLUSION

The KOOS showed acceptable relevance, construct validity, and responsiveness and moderate to high test-retest reliability for patients with tibial shaft fractures. Further validation of the psychometric properties of the KOOS for tibial shaft fractures may expand its usefulness for this patient group. [Orthopedics. 2025;48(3):146-152.].

Closed Management of a Bent Tibial Nail: Can Revision Be Avoided?: A Case Report

CASE

A 49-year-old gentleman sustained a closed, right tibia peri-implant fracture with a bent intramedullary nail. This resulted in a 17° valgus and 5° recurvatum deformity with fracture at the distal third of the tibial shaft. The patient underwent closed manipulation with an F-Tool and was reviewed by our unit over the following year.

CONCLUSION

This is the first case report of closed manipulation of a tibial fracture over a bent implant. This approach was successful in correcting deformity to within acceptable limits, achieved radiological union, and was associated with excellent patient-reported outcomes at all points of follow-up.

Imaging risk factors for predicting postoperative complications of intramedullary nailing for tibial fracture

OBJECTIVE

The objective of this study was to analyze the ratio of fracture site diameter to tibial isthmus diameter (TFI ratio) as a predictor of postoperative complications, including malunion and delayed union, after tibial intramedullary nailing for middle and lower tibial fractures.

METHODS

Data were collected from all adult patients older than 20 years of age who underwent tibial intramedullary nailing for middle and lower tibial fractures between January 2015 and January 2023 and were followed up for at least 1 year. Diabetes history, smoking history, fracture type, injury mechanism, surgical method, surgical approach, diameter of the medullary cavity at the fracture site, and diameter of the tibial isthmus were recorded. Logistic regression analysis was used to determine the variables affecting the occurrence of complications. The TFI ratio was used to calculate the sensitivity and specificity of the parameters, and ROC curves were generated to establish TFI ratio thresholds for predicting complications.

RESULTS

A total of 123 patients with middle and lower tibial fractures were treated with intramedullary nails. The mean age of the patients was 43.72 years (range, 21-81 years); 89 were males, and 34 were females. Univariate logistic regression analysis showed that fracture type, open reduction surgery, superior patellar approach, and TFI ratio were significantly correlated with postoperative complications after intramedullary nailing of a tibial fracture. Multivariate logistic regression analysis showed that the TFI ratio was an independent risk factor for complications (P = 0.001*). By using the TFI ratio as a predictor of complications, an ROC curve was generated to establish a threshold. The ROC curve showed that a TFI ratio ≥ 1.31 had a sensitivity of 0.89, a specificity of 0.71, and an area under the ROC curve of 0.82 for predicting complications.

CONCLUSIONS

The results of this study suggest that a wider intramedullary diameter and a shorter fixed length at the fracture site are associated with a higher incidence of complications after tibial intramedullary nailing. The TFI ratio may be used as a reliable parameter for predicting complications after such surgery. In patients with a high TFI ratio (≥ 1.31), additional reduction and fixation techniques may be needed to obtain and maintain fracture reduction.

Application of the Modified RUST Score in Tibial Bone Transport and Factors Associated with Docking Site Complications

Aim

Reconstruction of segmental bone defects with bone transport is a well-established treatment. Mechanical complications at the docking site after frame removal are common. These complications include malunion, non-union, axial deviation and refracture. A simple tool to assess the healing of the docking site is currently lacking. The aim of this study is to evaluate the use of the modified RUST (mRUST) score in the setting of bone transport and to identify factors associated with an increased risk of docking site complications.

Methods

This retrospective study was conducted at a single tertiary centre in South Africa, included 24 patients with a tibial bone defect treated with bone transport and a circular frame between 2014 and 2023. Demographic data, clinical and bone transport characteristics were recorded. Mechanical complications, such as fracture, non-union, any angulation >5°, shortening >5 mm, or any other complication requiring reoperation, were recorded. The mRUST was adapted as a ratio for the purpose of this study to overcome the common occurrence of cortices being obscured by the frame. The mRUST ratio was applied before and after frame removal for each patient by three appraisers. Comparison between the groups with and without complications was performed regarding bone transport characteristics, docking site configuration and mRUST ratio. The correlation of the score between radiographs before and after frame removal was assessed. The inter-rater reliability of the mRUST was analysed using Fleiss Kappa statistics for each cortex individually and the intraclass correlation coefficient (ICC) for the mRUST ratio.

Results

In this study, 20 men and 4 women with a median age of 26 years were included. The overall rate of mechanical complications after frame removal was 21.7%. Complications were all related to the docking site, with two angulations, two fractures and one non-union. Demographics, bone transport characteristics and mRUST ratio before and after frame removal were similar between the two groups. Regarding the configuration of the docking site, an angle of 45° or more between the bone surfaces was associated with the occurrence of mechanical complications (p < 0.001). The correlation of the mean mRUST ratio before and after frame removal showed a moderate relationship, with a Spearman correlation coefficient of 0.50 (p-value 0.13). The inter-rater reliability of the mRUST was "fair" (kappa 0.21-0.40) for the scoring of individual cortices, except for one score which was "slight" (kappa 0.00-0.20). The ICC of the mRUST ratio was 0.662 on radiographs with the frame, and 0.759 after frame removal.

Conclusion

This study did not find the mRUST or mRUST ratio useful in assessing the healing of the docking site to decide on the best time to remove the frame. However, a notable finding was that the shape and orientation of the bone ends meeting at the docking site might well be relevant to decrease complication rates. If the angle between the bony surfaces is 45° or more, it may be associated with an increased risk of complications. It may be worthwhile considering reshaping these bone ends at the time of debridement or formal docking procedure to be more collinear, in order to reduce the potential for mechanical complications such as non-union, axial deviation or refracture at the docking site.

How to cite this article

Kummer A, Nieuwoudt L, Marais LC. Application of the Modified RUST Score in Tibial Bone Transport and Factors Associated with Docking Site Complications. Strategies Trauma Limb Reconstr 2024;19(2):73-81.

Fracture gap and working length are important actionable factors affecting bone union after minimally invasive plate osteosynthesis for the treatment of simple diaphyseal or distal metaphyseal tibia fractures

INTRODUCTION

Indirect reduction of minimally invasive plate osteosynthesis (MIPO) can often result in delayed union in tibia fractures. This study evaluated several factors in MIPO in relation to bone union.

HYPOTHESIS

We hypothesized that the fracture gap, plate - tibia distance, or working length would have a substantial effect on the tibia union rate.

MATERIALS AND METHODS

Forty-one patients with simple diaphyseal or distal metaphyseal tibia fractures who underwent internal fixation surgery using the MIPO technique were divided into two groups: patients with delayed union and patients without delayed union. Non-actionable factors involving AO/OTA classification, fibula fracture and actionable factors including postoperative fracture gap, plate - tibia distance, working length in relation to parameters of bone union were compared between the two groups. Also cumulative rates of bone union and risk factors of delayed union according to variables of interest were investigated.

RESULTS

AO/OTA classification, site of fibula fracture, postoperative fracture gap, working length, and bone union rate of the two groups significantly differed (p<0.05). The cumulative rate of bone union during 1-year follow-up according to 43A tibia fracture, distal fibula fracture, fracture gap, and working length significantly differed between the two groups (p<0.05). By univariate Cox proportional hazards model, 43A tibia fracture, distal fibula fracture, facture gap, and short working length were risk factors for delayed union (p<0.05).

DISCUSSION

Non-actionable factors involving AO/OTA classification, distal fibula fracture and actionable factors including postoperative fracture gap, working length were significant factors affecting bone union after MIPO. The present study indicated that small fracture gap and long working length during MIPO might facilitate bone healing in tibia fracture.

LEVEL OF EVIDENCE

IV; single-center retrospective cohort study.

Implant retention in a rabbit model of fracture-related infection

Aims

Fracture-related infection (FRI) is commonly classified based on the time of onset of symptoms. Early infections (< two weeks) are treated with debridement, antibiotics, and implant retention (DAIR). For late infections (> ten weeks), guidelines recommend implant removal due to tolerant biofilms. For delayed infections (two to ten weeks), recommendations are unclear. In this study we compared infection clearance and bone healing in early and delayed FRI treated with DAIR in a rabbit model.

Methods

Staphylococcus aureus was inoculated into a humeral osteotomy in 17 rabbits after plate osteosynthesis. Infection developed for one week (early group, n = 6) or four weeks (delayed group, n = 6) before DAIR (systemic antibiotics: two weeks, nafcillin + rifampin; four weeks, levofloxacin + rifampin). A control group (n = 5) received revision surgery after four weeks without antibiotics. Bacteriology of humerus, soft-tissue, and implants was performed seven weeks after revision surgery. Bone healing was assessed using a modified radiological union scale in tibial fractures (mRUST).

Results

Greater bacterial burden in the early group compared to the delayed and control groups at revision surgery indicates a retraction of the infection from one to four weeks. Infection was cleared in all animals in the early and delayed groups at euthanasia, but not in the control group. Osteotomies healed in the early group, but bone healing was significantly compromised in the delayed and control groups.

Conclusion

The duration of the infection from one to four weeks does not impact the success of infection clearance in this model. Bone healing, however, is impaired as the duration of the infection increases.

Comparative bone healing with induced membrane technique (IMT) versus empty defects in septic and aseptic conditions in a novel rabbit humerus model

BACKGROUND

Long bone defects resulting from primary trauma or secondary to debridement of fracture-related infection (FRI) remain a major clinical challenge. One approach often used is the induced membrane technique (IMT). The effectiveness of the IMT in infected versus non-infected settings remains to be definitively established. In this study we present a new rabbit humerus model and compare the IMT approach between animals with prior infection and non-infected equivalents.

METHODS

A 5 mm defect was created in the humerus of New Zealand White rabbits (n = 53) and fixed with a 2.5 mm stainless steel plate. In the non-infected groups, the defect was either left empty (n = 6) or treated using the IMT procedure (PMMA spacer for 3 weeks, n = 6). Additionally, both approaches were applied in animals that were inoculated with Staphylococcus aureus 4 weeks prior to defect creation (n = 5 and n = 6, respectively). At the first and second revision surgeries, infected and necrotic tissues were debrided and processed for bacteriological quantification. In the IMT groups, the PMMA spacer was removed 3 weeks post implantation and replaced with a beta-tricalcium phosphate scaffold and bone healing observed for a further 10 weeks. Infected groups also received systemic antibiotic therapy. The differences in bone healing between the groups were evaluated radiographically using a modification of the radiographic union score for tibial fractures (RUST) and by semiquantitative histopathology on Giemsa-Eosin-stained sections.

RESULTS

The presence of S. aureus infection at revision surgery was required for inclusion to the second stage. At the second revision surgery all collected samples were culture negative confirming successful treatment. In the empty defect group, bone healing was increased in the previously infected animals compared with non-infected controls as revealed by radiography with significantly higher RUST values at 6 weeks (p = 0.0281) and at the end of the study (p = 0.0411) and by histopathology with increased cortical bridging (80% and 100% in cis and trans cortical bridging in infected animals compared to 17% and 67% in the non-infected animals). With the IMT approach, both infected and non-infected animals had positive healing assessments.

CONCLUSION

We successfully developed an in vivo model of bone defect healing with IMT with and without infection. Bone defects can heal after an infection with even better outcomes compared to the non-infected setting, although in both cases, the IMT achieved better healing.

The decisive early phase of bone regeneration

Bone has a remarkable endogenous regenerative capacity that enables scarless healing and restoration of its prior mechanical function, even under challenging conditions such as advanced age and metabolic or immunological degenerative diseases. However - despite much progress - a high number of bone injuries still heal with unsatisfactory outcomes. The mechanisms leading to impaired healing are heterogeneous, and involve exuberant and non-resolving immune reactions or overstrained mechanical conditions that affect the delicate regulation of the early initiation of scar-free healing. Every healing process begins phylogenetically with an inflammatory reaction, but its spatial and temporal intensity must be tightly controlled. Dysregulation of this inflammatory cascade directly affects the subsequent healing phases and hinders the healing progression. This Review discusses the complex processes underlying bone regeneration, focusing on the early healing phase and its highly dynamic environment, where vibrant changes in cellular and tissue composition alter the mechanical environment and thus affect the signalling pathways that orchestrate the healing process. Essential to scar-free healing is the interplay of various dynamic cascades that control timely resolution of local inflammation and tissue self-organization, while also providing sufficient local stability to initiate endogenous restoration. Various immunotherapy and mechanobiology-based therapy options are under investigation for promoting bone regeneration.

Functional outcomes and health-related quality of life after reconstruction of segmental bone loss in femur and tibia using the induced membrane technique

INTRODUCTION

The induced membrane technique (IMT), frequently called Masquelet technique, is an operative, two-staged technique for treatment of segmental bone loss. Previous studies mainly focused on radiological outcome parameters and complication rates, while functional outcomes and health-related quality of life after the IMT were sparsely reported.

MATERIALS AND METHODS

Retrospective study containing of a chart review as well as a clinical and radiological follow-up examination of all patients treated with the IMT at a single institution. The clinical outcomes were evaluated using the Lower Extremity Functional Scale (LEFS), the Short-Form-36 (SF-36) and the visual analog scale (VAS) for pain. The radiographic evaluation contained of standard anteroposterior and lateral, as well as hip-knee-ankle (HKA) radiographs.

RESULTS

Seventeen patients were included in the study. All had suffered high-energy trauma and sustained additional injuries. Ten bone defects were localized in the femur and seven in the tibia. Ten patients underwent additional operative procedures after IMT stage 2, among them three patients who contracted a postoperative deep infection. The median LEFS was 59 (15-80), and the SF-36 physical component summary (PCS) and mental component summary (MCS) were 41.3 (24.0-56.1) and 56.3 (13.5-66.2), respectively. The median length of the bone defect was 9 (3-15) cm. In 11 patients, union was obtained directly after IMT stage 2. Bone resorption was observed in two patients. At follow-up, 16 of the 17 bone defects had healed. The median follow-up was 59 months (13-177).

CONCLUSION

Our results show a high occurrence of complications after IMT stage 2 in segmental bone defects of femur and tibia requiring additional operative procedures. However, fair functional outcomes as well as a good union rate were observed at follow-up.

How to assess consolidation after foot and ankle arthrodesis with computed tomography. A systematic review

PURPOSES

Many studies have been performed that investigate consolidation after arthrodesis of foot and ankle joints. Consolidation in foot and ankle joints is best assessed by computed tomography (CT). However, no golden-standard methodology exists for radiological consolidation assessment from CT after ankle and foot arthrodesis. The aim of this review is to present an overview of the radiological methodologies for consolidation assessment, outcomes on reliability and validity and to advise which methodology should be used.

METHOD

Scientific databases were systematically searched. Eligible studies were studies that 1) performed foot or ankle arthrodesis, 2) mentioned radiological or CT follow-up in abstract, 3) performed postoperative CT in > 50% of patients. Two authors selected eligible studies and performed a risk of bias assessment with the COSMIN tool.

RESULTS

Risk of bias assessment showed that most studies (80%) were at high risk of bias due to poor methodology. The most popular method for consolidation assessment is by subjectively categorizing consolidation into consolidation groups, with a substantial reliability score. Another popular method is to calculate the fusion ratio and then apply a fusion threshold, to distinguish between fused and non-fused joints. This method had an excellent reliability score. In most studies a fusion threshold of 50% is used. However, four studies in this review showed that a 30% fusion threshold may by more valid.

CONCLUSION

Based on the results of this review we would advise to calculate fusion threshold and apply a 30% fusion threshold to distinguish fused from non-fused foot and ankle joints.

Secondary intramedullary nailing for open tibial shaft fractures. Comparison of a one-stage versus two-stage surgical procedure

INTRODUCTION

The objective of this study was to compare the rates of radiological and clinical complications after sequential treatment of a tibial shaft fracture by external fixation followed by secondary nailing with an early-stage conversion (C1S) versus a two-stage late conversion (C2S). The hypothesis of this work was that treatment with C1S does not increase the risk of surgical site infections compared to C2S, and allows faster healing with a lower malunion rate.

MATERIAL AND METHODS

We carried out a retrospective and comparative study based on the files of the traumatology department of the Édouard Herriot University Hospital in Lyon. We reviewed the records of patients who presented with a Gustilo grade 1, 2 or 3a open tibial fracture treated with external fixation with conversion by intramedullary nailing within 6 months from January 2010 to December 2020. We assessed the occurrence of Surgical Site Infections (SSI), consolidation time, time until resumption of weight bearing and the malunion rate.

RESULTS

Of the 55 patients included, a C1S procedure was performed in 25 cases (45.5%) versus 30 cases (54.5%) for C2S. No significant difference was found concerning the occurrence of SSI after intramedullary nailing between the two groups (p=0.81). A significant difference was observed in terms of bone healing (p=0.036) and the malunion rate (0.0013) in favor of nailing in one stage.

DISCUSSION

The strategy of converting an open leg fracture early, in one stage (C1S), after initial external fixator placement allows for faster healing and weight bearing, while ensuring a lower malunion rate compared to that of a late two-stage conversion. In the absence of a scar at the time of intramedullary nailing, C1S does not increase the risk of surgical site infections. While the choice of a late and sequential two-stage operation is likely related to the surgeon's apprehension around conversion of an open leg fracture by intramedullary nailing, this study could promote the use of C1S in a greater number of situations.

LEVEL OF EVIDENCE

IV.

Bone Union Assessment with Computed Tomography (CT) and Statistical Associations with Mechanical or Histological Testing: A Systematic Review of Animal Studies

Objective and accurate assessment of bone union after a fracture, arthrodesis, or osteotomy is relevant for scientific and clinical purposes. Bone union is most accurately imaged with computed tomography (CT), but no consensus exists about objective assessment of bone union from CT images. It is unclear which CT-generated parameters are most suitable for bone union assessment. The aim of this review of animal studies is to find which CT-generated parameters are associated most strongly with actual bone union. Scientific databases were systematically searched. Eligible studies were studies that (1) were animal studies, (2) created a fracture, (3) assessed bone union with CT, (4) performed mechanical or histological testing as measure of actual bone union, and (5) associated CT-generated outcomes to mechanical or histological testing results. Two authors selected eligible studies and performed risk of bias assessment with QUADAS-2 tool. From 2567 studies that were screened, thirteen studies were included. Most common CT parameters that were investigated were bone mineral density, bone volume, and total callus volume. Studies showed conflicting results concerning the associations of these parameters with actual bone union. CT-assessed torsional rigidity (assessed by three studies) and callus density (assessed by two studies) showed best results. The studies investigating these two parameters reported moderate to strong associations with actual bone union. CT-assessed torsional rigidity and callus density seem the most promising parameters to represent actual bone union after a fracture, arthrodesis, or osteotomy.Prospero trial registration number: CRD42020164733.

Tibial shaft fractures in the adolescents: treatment outcomes and the risk factors for complications

BACKGROUND

Tibial shaft fractures are common injuries in the adolescent age group. The optimal method of treatment in this age group is still controversial. It relies on several factors including patient's age, fracture pattern, fracture location, and the condition of the soft tissue envelope. The purpose of this study was to report the clinical and radiographic outcomes of adolescent tibial shaft fractures treatment at a level-I trauma center.

METHODS

This retrospective study reviewed consecutive patients between 10 and 18 years of age who suffered from tibial shaft fractures between 2009 and 2018 at a level-I trauma center. Outcomes of interest were the successful fracture union (primary outcome) as evaluated by the Radiographic Union Scale in Tibial fractures (RUST) and the complications (secondary outcomes).

RESULTS

Fifty-two consecutive adolescent patients treated for tibial shaft fractures using elastic stable intramedullary nails (ESIN), interlocking nails, plates and screws, external fixators, and casts were included in the study. The mean follow-up period was 27.4 months. There was no statistically significant difference in the union rate and time to fracture union between the different treatment methods. Subject weight, fracture type, and method of treatment were significant predictors for the RUST scores at 12 weeks post-operative. Adolescents with heavier bodyweight correlated with lower RUST scores (p<0.001). Open fractures were associated with significantly longer time to union (p<0.001) and lower RUST scores (p<0.001) compared to closed fractures. The patients treated with interlocking nailing showed higher RUST scores than the casting treatment group (p = 0.01). There were no statistically significant differences in complication rates between the fixation methods. Union time was significantly longer with complications than without complications (p = 0.01). Open fractures had higher complication rates compared to closed fractures. In the multivariate logistic model, patients with open fracture were 5.5 times more likely to have complications (OR=5.46; p = 0.04).

CONCLUSION

Tibial shaft fractures in adolescents can be treated with several methods including ESIN, interlocking nail, plate and screws, external fixation, and casting. All are valid treatments for adolescent tibial shaft fractures and can achieve favorable outcomes. No single treatment method applies to all patients. Each method has advantages, disadvantages, and specific indications.

Progression of Tibia Fracture Healing Using RUST: Are Early Radiographs Helpful?

OBJECTIVES

To report the progression of radiographic healing after intramedullary nailing of tibial shaft fractures using the Radiographic Union Score for Tibial fractures (RUST) and determine the ideal timing of early postoperative radiographs.

DESIGN

Retrospective case series.

SETTING

Urban academic Level 1 trauma center.

PATIENTS/PARTICIPANTS

Three hundred three patients with acute tibial shaft fractures underwent intramedullary nailing between 2006 and 2013, met inclusion criteria, and had at least 3 months of radiographic follow-up.

INTERVENTION

Baseline demographic, injury, and surgical data were recorded for each patient. Each set of postoperative radiographs were scored using RUST and evaluated for implant failure.

MAIN OUTCOME MEASUREMENTS

Postoperative time distribution for each RUST score, RUST score distribution for 4 common follow-up time points, and the presence and timing of implant failure.

RESULTS

The fifth percentile and median times, respectively, for reaching "any radiographic healing" (RUST = 5) was 4.0 weeks and 8.4 weeks, "radiographically healed" (RUST = 9) was 12.1 and 20.9 weeks, and "healed and remodeled" (RUST = 12) was 23.5 weeks and 47.7 weeks. At 6 weeks, 84% of radiographs were scored as RUST ≤ 6 (2 or fewer cortices with callus). No implant failure occurred within the first 8 weeks after surgery, and the indication for all 7 reoperations within this period was apparent on physical examination or immediate postoperative radiographs.

CONCLUSIONS

The median time to radiographic union (RUST = 9) after tibial nailing was approximately 20 weeks, and little radiographic healing occurred within the first 8 weeks after surgery. Routine radiographs in this period may offer little additional information in the absence of clinical concerns such as new trauma, malalignment, or infection.

LEVEL OF EVIDENCE

Diagnostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Squat and smile assessment in predicting healing of lower limb fractures fixed with a SIGN nail

BACKGROUND

Irrespective of the treatment method, union is the ultimate goal of any fracture treatment. However, nowadays, rather than the physician-based clinico-radiological methods, the patient-reported outcome measurements assessing their quality of life and function are gaining much popularity. This is specifically true in the part of the world where the patient needs almost complete degree of hip/knee flexion - for social, cultural, religious or occupational reason(s). The ability to squat can assess the mobility and stability of joints and thus the quality of squatting is a proxy reflection of the functional outcome after fixation of lower limb fracture. Thus, we studied to determine the inter-observer and intra-observer reliability of Radiographic Union Score for Tibia (RUST) and Squat and Smile (S & S) test in clinical photograph. We further calculated the sensitivity and specificity of S & S test in predicting healing of lower limb fracture fixed by intramedullary interlocking nail considering RUST as the gold standard.

METHODS

This was a retrospective study of prospectively collected data of solid Surgical Implant Generation Network (SIGN) intramedullary interlocking nailing from a single, university-based, high volume tertiary center where 56 consecutive adults with either tibial or femoral shaft fractures fixed with a SIGN nail within one year and not requiring any surgery till minimum of eighteen-month follow-up were included. Cases without either Anterior-Posterior (AP) view and/or Lateral (Lat.) view follow-up x-ray(s) or proper S & S clinical photograph (at least 1.5-year post fixation) were excluded. The x-rays (RUST criteria) and clinical photograph (S & S grading) were scored by two independent and blinded observers each and repeated after 1 month.

RESULTS

The overall intra-observer reliability was from 0.773 to 0.825 and inter-observer reliability from 0.635 to 0.757 for RUST scoring which was from 0.687 to 0.785 and from 0.301 to 0.650 respectively for S & S scoring. The sensitivity and specificity of S & S in predicting fracture healing were up to 82.22% and 63.64% respectively.

CONCLUSION

The S & S test is reliable to predict the healing of lower limb fracture fixed with an intramedullary nail. The test is more useful to determine healed fractures than to determine non-healed ones. (sensitivity being higher than specificity).