Contact stress aberrations following imprecise reduction of simple tibial plateau fractures

Comparative finite element analysis of contact and stress distribution in tibiotalar articular cartilage: Healthy versus varus ankles

Background

The distribution of forces within the ankle joint plays a crucial role in joint health and longevity. Loading disorders affecting the ankle joint can have significant detrimental effects on daily life and activity levels. This study aimed to enhance our understanding of the mechanical behavior of tibiotalar joint articular cartilages in the presence of varus deformity using finite element analysis (FEA) applied to patient-specific models.

Methods

Two personalized ankle models, one healthy and another with varus deformity, were created based on CT scan images. Four static loading scenarios were simulated at the center of pressure (COP), coupled to the hindfoot complex. The contact area, contact pressure, and von Mises stress were computed for each cartilage.

Results

It was found that the peak contact pressure increased by 54% in the ankle with varus deformity compared to the healthy ankle model. Furthermore, stress concentrations moving medially were observed, particularly beneath the medial malleolus, with an average peak contact pressure of 3.5 MPa and 4.7 MPa at the tibial and talar articular cartilages, respectively.

Conclusion

Varus deformities in the ankle region have been consistently linked to elevated contact pressure, increasing the risk of thinning, degeneration, and eventual onset of osteoarthritis (OA), emphasizing the need for prompt interventions aimed at mitigating complications.

What Is the Patient-reported Outcome and Complication Incidence After Operative Versus Nonoperative Treatment of Minimally Displaced Tibial Plateau Fractures?

BACKGROUND

Much controversy remains about whether minimally displaced tibial plateau fractures should be treated operatively or nonoperatively. It is generally accepted that gaps and stepoffs up to 2 mm can be tolerated, but this assumption is based on older studies using plain radiographs instead of CT to assess the degree of initial fracture displacement. Knowledge regarding the relationship between the degree of fracture displacement and expected functional outcome is crucial for patient counseling and shared decision-making, specifically in terms of whether to perform surgery.

QUESTIONS/PURPOSES

(1) Is operative treatment associated with improved patient-reported outcomes compared with nonoperative treatment in minimally displaced tibial plateau fractures (fractures with up to 4 mm of displacement)? (2) What is the difference in the risk of complications after operative versus nonoperative treatment in minimally displaced tibial plateau fractures?

METHODS

A multicenter, cross-sectional study was performed in patients treated for tibial plateau fractures between 2003 and 2019 at six hospitals. Between January 2003 and December 2019, a total of 2241 patients were treated for tibial plateau fractures at six different trauma centers. During that time, the general indication for open reduction and internal fixation (ORIF) was intra-articular displacement of > 2 mm. Patients treated with ORIF and those treated nonoperatively were potentially eligible; 0.2% (4) were excluded because they were treated with amputation because of severe soft tissue damage, whereas 4% (89) were excluded because of coexisting conditions that complicated outcome measurement including Parkinson disease, cerebrovascular accident, or paralysis (conditions causing an inability to walk). A further 2.7% (60) were excluded because their address was unknown, and 1.4% (31) were excluded because they spoke a language other than Dutch. Based on that, 1328 patients were potentially eligible for analysis in the operative group and 729 were potentially eligible in the nonoperative group. At least 1 year after injury, all patients were approached and asked to complete the Knee injury and Osteoarthritis Outcome Scale (KOOS) questionnaire. A total of 813 operatively treated patients (response percentage: 61%) and 345 nonoperatively treated patients (response percentage: 47%) responded to the questionnaire. Patient characteristics including age, gender, BMI, smoking, and diabetes were retrieved from electronic patient records, and imaging data were shared with the initiating center. Displacement (gap and stepoff) was measured for all participating patients, and all patients with minimally displaced fractures (gap or stepoff ≤ 4 mm) were included, leaving 195 and 300 in the operative and nonoperative groups, respectively, for analysis here. Multivariate linear regression was performed to assess the association of treatment choice (nonoperative or operative) with patient-reported outcomes in minimally displaced fractures. In the multivariate analysis, we accounted for nine potential confounders (age, gender, BMI, smoking, diabetes, gap, stepoff, AO/OTA classification, and number of involved segments). In addition, differences in complications after operative and nonoperative treatment were assessed. The minimum clinically important differences for the five subscales of the KOOS are 11 for symptoms, 17 for pain, 18 for activities of daily living, 13 for sports, and 16 for quality of life.

RESULTS

After controlling for potentially confounding variables such as age, gender, BMI, and AO/OTA classification, we found that operative treatment was not associated with an improvement in patient-reported outcomes. Operative treatment resulted in poorer KOOS in terms of pain (-4.7 points; p = 0.03), sports (-7.6 points; p = 0.04), and quality of life (-7.8 points; p = 0.01) compared with nonoperative treatment, but those differences were small enough that they were likely not clinically important. Patients treated operatively had more complications (4% [7 of 195] versus 0% [0 of 300]; p = 0.01) and reoperations (39% [76 of 195] versus 6% [18 of 300]; p < 0.001) than patients treated nonoperatively. After operative treatment, most reoperations (36% [70 of 195]) consisted of elective removal of osteosynthesis material.

CONCLUSION

No differences in patient-reported outcomes were observed at midterm follow-up between patients treated surgically and those treated nonsurgically for tibial plateau fractures with displacement up to 4 mm. Therefore, nonoperative treatment should be the preferred treatment option in minimally displaced fractures. Patients who opt for nonoperative treatment should be told that complications are rare, and only 6% of patients might undergo surgery by midterm follow-up. Patients who opt for surgery of a minimally displaced tibial plateau fracture should be told that complications may occur in up to 4% of patients, and 39% of patients may undergo a secondary intervention (most of which are elective implant removal).

LEVEL OF EVIDENCE

Level III, therapeutic study.

Prospective evaluation of the surgical stabilization and outcome of canine tibial plateau fractures in three cases

OBJECTIVE

To report the surgical approaches and stabilization of lateral and medial tibial plateau fractures (TPF), as well as the long-term outcome following repair.

STUDY DESIGN

Prospective series of three client-owned dogs.

ANIMALS

Three dogs.

METHODS

For the two lateral TPF cases (Unger type 41-B1), the surgical approach included separation of the lateral collateral ligament and long digital extensor tendon. The lateral meniscus was elevated to allow visualization of the tibial surface and assess fracture reduction. The first case was repaired using two 2.0 mm lag screws (with washers). The second case sustained a lateral TPF, fibular fracture and concurrent tubercle of Gerdy fracture. Both tibial fractures were stabilized using two 2.0 mm lag screws with washers and two 0.9 mm Kirschner wires (K-wires). A third case, diagnosed with an Unger type 41-B2 medial TPF, was treated using 0.9 mm K-wires and 22-gauge tension band.

RESULTS

There were no major complications noted. One minor complication occurred (screw yield two weeks postoperatively). By 8 weeks, all patients reached clinical union with good limb function. Owners were contacted 9-36 months postoperatively. LOAD scores and examinations were performed for two of three patients; the third patient was not contactable after relocating out of state. Both cases with completed questionnaires had a LOAD score of 5/52.

CONCLUSION

Tibial plateau fractures are rare in canine patients. While challenging, they can be successfully managed using a combination of lag screws, K-wires, and tension band.

CLINICAL SIGNIFICANCE

Surgical stabilization of TPF is feasible and may reduce the risk of meniscal injury.

Innovative Approach to Lateral Tibial Plateau Fracture: A Case Study on Anterolateral Submeniscal Arthrotomy With Cement Augmentation and Screw Fixation

Lateral tibial plateau fractures are generally present as depressed fractures. The lateral tibial plateau is more common than the medial tibial plateau, often due to a bumper injury. If depressed fragments are more than 8-10 mm, then surgical management is usually needed. Anterolateral fixation is frequently used for unicondylar lateral tibial plateau fractures. Here, we present an articular depressed lateral tibia plateau fracture in a Schatzker type 3 case. The fracture was managed through an anterolateral approach with sub-meniscal arthrotomy, allowing for direct visualization and subsequent fixation using bone cement and a cannulated cancellous screw. Postoperative imaging confirmed proper reduction, and the patient had a satisfactory outcome..

Mismatch between Clinical-Functional and Radiological Outcome in Tibial Plateau Fractures: A Retrospective Study

BACKGROUND

The evaluation of tibial plateau fractures (TPF) encompasses the assessment of clinical-functional and radiological parameters. In this study, the authors aimed to investigate the potential correlation between these parameters by utilizing both the clinical-functional and the modified radiological Rasmussen score.

METHODS

In this retrospective monocentric study conducted at a level-I trauma center, patients who underwent surgery between January 2014 and December 2019 due to a TPF were included. The clinical-functional Rasmussen score prior to the injury, at 1-year postoperatively, and during the last follow-up (minimum 18 months) was assessed using a standardized questionnaire. Additionally, the modified radiological Rasmussen score was determined at the 1-year postoperative mark using conventional radiographs in two planes.

RESULTS

A total of 50 patients were included in this study, comprising 40% (n = 20) men, and 60% (n = 30) women, with an average age of 47 ± 11.8 years (range 26-73 years old). Among them, 52% (n = 26) had simple fractures (classified according to Schatzker I-III), while 48% (n = 24; according to Schatzker IV-VI) had complex fractures. The mean follow-up was 3.9 ± 1.6 years (range 1.6-7.5 years). The functional Rasmussen score assessed before the injury and at follow-up showed an "excellent" average result. However, there was a significant difference in the values of complex fractures compared to before the injury. One year postoperatively, both the clinical-functional score and the modified radiological score demonstrated a "good" average result. The "excellent" category was more frequently observed in the functional score, while the "fair" category was more common in the radiological score. There was no agreement between the categories in both scores in 66% of the cases.

CONCLUSIONS

The data from this retrospective study demonstrated that patients with TPF are able to achieve a nearly equivalent functional level in the medium-term after a prolonged recovery period, comparable to their pre-injury state. However, it is important to note that the correlation between clinical-functional and radiological parameters is limited. Consequently, in order to create prospective outcome scores, it becomes crucial to objectively assess the multifaceted nature of TPF injuries in more detail, both clinically and radiologically.

Top 50 Cited Papers on Tibial Plateau Fracture Management: A Bibliometric Analysis and Review

Purpose

The orthopaedic surgeons, especially the young budding surgeons should have a well-balanced knowledge of the past evidence as well the current evidence in the literature for the appropriate as well as optimum management of tibial plateau fractures. Bibliometric analysis of the top-cited papers on tibial plateau fracture management can help know their concurrent interests, deficiencies and conflicting issues regarding their management. This study aimed to identify the 50 most cited research articles in tibial plateau research and analyse their characteristics.

Methods

We searched the Thompson Reuters Web of Science database for articles relevant to tibial plateau fracture and prepared a list of top 50 cited articles that included original articles and review articles concerning tibial plateau fractures. The included articles were analysed for contributing journals, corresponding author's country, publication year, cumulative citations, annual citations, citation trends over time, level of evidence and a qualitative review.

Results

The search strategy resulted in 2263 articles. The top 50 cited articles were published from 1974 to 2014 and belonged to 12 journal sources. There were 47 original articles and 3 review articles. The average citations per article were 126.2, and the annual citations per article were 6.478 per year. The top-cited articles were relevant to the strategies in the management, classification, fracture reduction, articular restoration, types and number of fixation devices, surgical approaches, associated menisco-ligamentous injuries and applicability of bone grafts/substitutes in tibial plateau fractures.

Conclusion

The current bibliometric analysis summarises the top-cited evidence concerning tibial plateau fractures and can be a potential resource for reviewing and locating the same. The analysis shows that most top-cited evidence belongs to the year 2000 onwards. Also, recent articles have a higher annual citation rate. A limited number of journals and mostly, western countries have contributed to the top-cited evidence. Whilst the top-cited evidence has touched several aspects of tibial plateau fractures, it is in the form of level IV case series. It needs better prospective evidence to establish sound recommendations.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43465-023-00932-4.

Posteromedial Submeniscal Arthrotomy and Fixation with a Posteromedial Rim Plate in a Comminuted Medial Tibial Plateau Fracture

Medial tibial plateau fractures generally present as simple metaphyseal fractures; however, certain cases may present as comminuted articular fractures. Medial and posteromedial anatomical plates have traditionally been used for their management; nevertheless, not all cases can be successfully managed using these implants. We present a comminuted posteromedial Schatzker type VI tibial plateau fracture case. Direct visualization and subsequent fixation using a posteromedial rim plate were achieved through a posteromedial approach and submeniscal arthrotomy. The adequate joint reduction and the obtained stability allowed satisfactory clinical and radiological outcomes. This variation of the classic posteromedial approach and the use of a posteromedial rim plate provide an alternative when facing comminuted medial tibial plateau fractures.

Influence of articular step-off on contact mechanics in fractures of the posterolateral-central tibial plateau - a biomechanical study

BACKGROUND

The posterior quadrants of the tibial plateau are frequently involved in OTA type C tibial plateau fractures. The biomechanical influence of a residual articular step-off of the posterolateral-central (PLC) segment, which is difficult to visualize intraoperatively, remains unclear. Therefore, aim of this study was to investigate the contact area and stress of the tibial plateau in cases of different articular step-offs of the PLC segment.

METHODS

Seven human cadaveric knees were used to simulate articular impressions of the PLC segment with step-offs of 1 mm, 3 mm, and 5 mm. The knees were axially loaded up to 150 N during a total of 25 dynamic cycles of knee flexion up to 90°. Pressure mapping sensors were inserted into the medial and lateral joint compartments beneath the menisci to measure articular contact area and stress.

RESULTS

Between 60° and 90° of knee flexion, increasing PLC segment impressions of the tibial plateau led to increasing contact stress and a significantly reduced contact area. The largest decrease in the contact area was 30 %, with an articular step-off of 5 mm (0.003). An increase in contact stress, especially from a 3-mm step-off, was measured, with a doubling of the mean contact stress at 3-mm and 5-mm step-offs and 90° knee flexion (p = 0.06/0.05).

CONCLUSION

From a biomechanical point of view, posterior impressions of the PLC segment greater than a 1-mm step-off should be addressed as anatomically as possible, especially in active patients with the need for higher knee flexion angles.

Influence of reduction quality on functional outcome and quality of life in the surgical treatment of tibial plateau fractures: A retrospective cohort study

BACKGROUND

Despite a substantial improvement in the operative treatment of tibial plateau fractures, the surgical procedure remains controversial and is generally challenging, as patients may develop postoperative arthritis and functional impairment of the knee joint.

HYPOTHESIS

In the surgical treatment of tibial plateau fractures the intraoperative reposition quality has the greatest influence on the postoperative outcome, whereby misalignments of≥2mm lead to a worse result.

PATIENTS AND METHODS

Forty-one patients with tibial plateau fractures were postoperatively examined. The operative treatment was performed under reduction control using an intraoperative 3D C-arm. The follow-up collective was divided into two groups depending on the intraoperative reduction result. The postoperative results were then evaluated using the following parameters: Lysholm score, Rasmussen score, Tegner score, SF-36 score, range of motion and pain level.

RESULTS

Group 1 (articular surface incongruencies<2mm) tended to achieve a better result in all scores than group 2 (articular surface incongruencies≥2mm), in the Lysholm score (p=0.039), in the comparison of the range of motion (p=0.012) and the pain level (p=0.039) this was significant. Group 1 achieved an average of 90.71 points (group 2: 78.74) in the Lysholm score. The average range of motion of the knee joint was 138.93° in group 1 (group 2: 127.78°). The average value of the current pain level in group 1 was 1.14 (group 2: 2.63).

DISCUSSION

Both study groups achieved a very good result compared to the available literature. It appears that reduction quality - which can be analyzed with intraoperative 3D imaging - plays the most important role in postoperative quality of life and functional outcome. Intraoperative adjustments of the reduction should therefore be performed on joint surface irregularities with a size above 2mm.

LEVEL OF EVIDENCE

III; retrospective case control study.

Tekscan analysis programs (TAP) for quantifying dynamic contact mechanics

This short communication provides details on customized Tekscan Analysis Programs (TAP) which extract comprehensive contact mechanics metrics from piezoelectric sensors in articulating joints across repeated loading cycles. The code provides functionality to identify regions of interest (ROI), compute contact mechanic metrics, and compare contact mechanics across multiple test conditions or knees. Further, the variability of identifying ROIs was quantified between seven different users and compared to an expert. Overall, the contribution of four variables were studied: two knee specimens; two points in the gait cycle; two averaging methods; and seven observers, to determine if variations in these values played a role in accurately quantifying the ROI. The relative error between the force ratio from each observer's ROI and the expert ROI was calculated as the output of interest. A multivariate linear mixed effects model was fit to the four variables for the relative error with an observer- and knee-specific random intercept. Results from the fitted model showed a statistically significant difference at the 0.05 level in the mean relative errors at the two gait points. Additionally, variability in the relative errors attributed to the observer, knee, and random errors was quantified. To reduce variability amongst users, by ensuring low inter-observer variability and increasing segmentation accuracy of knee contact mechanics, a training module and manual have been included as supplemental material. By sharing this code and training manual, we envisage that it can be used and modified to analyze outputs from a range of sensors, joints, and test conditions.

Biomechanical Comparison of 2 Double Plating Methods in a Coronal Fracture Model of Bicondylar Tibial Plateau Fractures

OBJECTIVES

Because management of bicondylar tibial plateau fractures are complicated even for expert surgeons, with using a coronal fracture model, we aimed to compare 2 kinds of double locked plating techniques that consisted of the lateral locking plate and the medial locking plate inserted medial anteriorly (MA-ly) or medial posteriorly (MP-ly).

METHODS

Fourteen fresh-frozen tibias stabilized with the MA or MP methods were allocated into 2 groups with similar bone mineral density values. Implanted samples were tested under incremental fatigue loading conditions using a customized load applicator. An optical motion tracking system was used to assess relative displacements and rotations of fracture fragments during loading. Static and dynamic global stiffness, failure load, failure cycles, as well as movements of fracture fragments were measured.

RESULTS

There were no significant differences between the 2 fixation methods regarding global stiffness, failure load, or failure cycles (P = 0.67-0.98, depending on the parameter). The kinematic evaluations, however, revealed that different positions of the medial locking plates altered the directions of movements for the medial-anterior or medial-posterior fracture segments.

CONCLUSIONS

The mechanical stability of tibia-implant constructs fixed with the double plating methods was not remarkably affected by the location of the medial locking plate. Depending on clinical conditions and surgeons' preferences, bicondylar tibial plateau fractures can be managed with either MA or MP methods.

A lateral fracture step-off of 2mm increases intra-articular pressure following tibial plateau fracture

INTRODUCTION

The aim of this study was to evaluate the effects of increasing posttraumatic step-offs after lateral tibial plateau fracture reduction on the intra-articular pressure.

MATERIALS AND METHODS

In eight fresh-frozen human cadaveric knees with intact menisci, a standardized sagittal osteotomy of the lateral tibial condyle was performed as an OTA/AO type 41-B1 fracture-model. The fragment was fixed by a customized sled including an angular stable tibia plate to evaluate step-offs from 0 mm to 8 mm in 1mm increments. In a servo-hydraulic testing machine, an axial force was applied to the tibial plateau in 0° (700N), 15° (700N), 30° (700N), 60° (350N), and 90 ° (350N) of flexion while the joint pressure was recorded by two pressure sensors.

RESULTS

A 1mm step-off did not result in an increased joint pressure. At 60° of flexion a 2mm step-off increased the lateral joint pressure by 61.84kPa (P = 0.0027). In 30° of flexion, a 3mm step raised the lateral joint pressure by 66.80kPa (p = 0.0017), whereas in 0°, 15° and 90° of flexion, a 4mm step increased the pressure by >50kPa (P < 0.05). Concomitant medial joint pressure increments were lower than those in the lateral plateau. A significant increase of 19-24kPa in the medial joint pressure was detected in 90° of flexion with a 1mm lateral step (P = 0.0075), in 15° and 60° of flexion with a 2mm step (P < 0.05), in 0° of flexion with a 4mm step (P = 0.0215) and in 30° of flexion with a 7mm step (P = 0.0487).

CONCLUSION

Lateral fracture step-offs of 2mm or larger should be reduced intraoperatively to avoid large increases in lateral joint pressure.

Autologous versus synthetic bone grafts for the surgical management of tibial plateau fractures: a systematic review and meta-analysis of randomized controlled trials

Aims

Our objective was to conduct a systematic review and meta-analysis, to establish whether differences arise in clinical outcomes between autologous and synthetic bone grafts in the operative management of tibial plateau fractures.

Methods

A structured search of MEDLINE, EMBASE, the online archives of Bone & Joint Publishing, and CENTRAL databases from inception until 28 July 2021 was performed. Randomized, controlled, clinical trials that compared autologous and synthetic bone grafts in tibial plateau fractures were included. Preclinical studies, clinical studies in paediatric patients, pathological fractures, fracture nonunion, or chondral defects were excluded. Outcome data were assessed using the Risk of Bias 2 (ROB2) framework and synthesized in random-effect meta-analysis. The Preferred Reported Items for Systematic Review and Meta-Analyses guidance was followed throughout.

Results

Six studies involving 353 fractures were identified from 3,078 records. Following ROB2 assessment, five studies (representing 338 fractures) were appropriate for meta-analysis. Primary outcomes showed non-significant reductions in articular depression at immediate postoperative (mean difference -0.45 mm, p = 0.25, 95%confidence interval (CI) -1.21 to 0.31, I² = 0%) and long-term (> six months, standard mean difference -0.56, p = 0.09, 95% CI -1.20 to 0.08, I² = 73%) follow-up in synthetic bone grafts. Secondary outcomes included mechanical alignment, limb functionality, and defect site pain at long-term follow-up, perioperative blood loss, duration of surgery, occurrence of surgical site infections, and secondary surgery. Mean blood loss was lower (90.08 ml, p < 0.001, 95% CI 41.49 to 138.67) and surgery was shorter (16.17 minutes, p = 0.04, 95% CI 0.39 to 31.94) in synthetic treatment groups. All other secondary measures were statistically comparable.

Conclusion

All studies reported similar methodologies and patient populations; however, imprecision may have arisen through performance variation. These findings supersede previous literature and indicate that, despite perceived biological advantages, autologous bone grafting does not demonstrate superiority to synthetic grafts. When selecting a void filler, surgeons should consider patient comorbidity, environmental and societal factors in provision, and perioperative and postoperative care provision.

Cite this article: Bone Jt Open 2022;3(3):218–228.

Management of Canine Y-T Humeral Fractures Using Titanium Polyaxial Locking Plates in 17 Dogs

The objective of this study was to document the short- and medium-to-long-term outcomes and complication rates of Y-T humeral condylar fractures fixed using titanium polyaxial locking plate (T-PLP). A retrospective review was performed of the medical records and radiographs of dogs with a Y-T humeral condylar fracture treated with T-PLP at a single veterinary referral center (2012–2018). Seventeen cases met the inclusion criteria. Medium- to long-term follow-up (.6 mo) information was derived using the Liverpool Osteoarthritis in Dogs (LOAD) questionnaire. Recorded complications were catastrophic (1/17) and minor (2/17). Gait at 10–12 wk following surgery was subjectively assessed as good or excellent for 13 cases. Radiographic bone union was achieved in 7/12 cases at 4–6 wk. LOAD scores obtained a mean of 15 mo (range 6–29 mo) following surgery and indicated no or mild impairment in 15/16 and moderate functional impairment in 1. The application of T-PLP for the treatment of Y-T humeral condylar fractures resulted in adequate stabilization allowing successful fracture healing and medium- to long-term outcomes comparable to previous reports. According to results of LOAD testing, the medium- to long-term follow-up suggests that clients were aware of mild to moderate functional impairment in all cases.

Initial displacement of the intra-articular surface after articular fracture correlates with PTA in C57BL/6 mice but not "superhealer" MRL/MpJ mice

Posttraumatic arthritis (PTA) occurs commonly after articular fracture and may arise, in part, from joint surface incongruity after injury. MRL/MpJ (MRL) "super-healer" mice are protected from PTA compared to C57BL/6 (B6) mice following articular fracture. However, the relationship between the initial displacement of the articular surface, biologic response, and susceptibility to PTA after fracture remains unclear. The objective of this study was to assess whether joint incongruity after articular fracture, as measured by in vivo micro-computed tomography (microCT), could predict pathomechanisms of PTA in mice. B6 and MRL mice (n = 12/strain) received a closed articular fracture (fx) of the left tibial plateau. Articular incongruity was quantified as bone surface deviations (BSD) for each in vivo microCT scan obtained from pre-fx to 8 weeks post-fx, followed by histologic assessment of arthritis. Serum concentrations of bone formation (PINP) and bone resorption (CTX-I) biomarkers were quantified longitudinally. Both strains showed increases in surface incongruity over time, as measured by increases in BSD. In B6 mice, acute surface incongruity was significantly correlated to the severity of PTA (R ²  = 0.988; p = .0006), but not in MRL mice (R ²  = 0.224; p = .220). PINP concentrations significantly decreased immediately post-fx in B6 mice (p = .023) but not in MRL mice, indicating higher bone synthesis in MRL mice. MRL/MpJ mice demonstrate a unique biologic response to articular fracture such that the observed articular bone surface displacement does not correlate with the severity of subsequent PTA. Clinical Relevance: Identifying therapies to enhance acute biologic repair following articular fracture may mitigate the risk of articular surface displacement for PTA.

Experimental Drillable Magnesium Phosphate Cement Is a Promising Alternative to Conventional Bone Cements

Clinically used mineral bone cements lack high strength values, absorbability and drillability. Therefore, magnesium phosphate cements have recently received increasing attention as they unify a high mechanical performance with presumed degradation in vivo. To obtain a drillable cement formulation, farringtonite (Mg₃(PO₄)₂) and magnesium oxide (MgO) were modified with the setting retardant phytic acid (C₆H₁₈O₂₄P₆). In a pre-testing series, 13 different compositions of magnesium phosphate cements were analyzed concentrating on the clinical demands for application. Of these 13 composites, two cement formulations with different phytic acid content (22.5 wt% and 25 wt%) were identified to meet clinical demands. Both formulations were evaluated in terms of setting time, injectability, compressive strength, screw pullout tests and biomechanical tests in a clinically relevant fracture model. The cements were used as bone filler of a metaphyseal bone defect alone, and in combination with screws drilled through the cement. Both formulations achieved a setting time of 5 min 30 s and an injectability of 100%. Compressive strength was shown to be ~12–13 MPa and the overall displacement of the reduced fracture was <2 mm with and without screws. Maximum load until reduced fracture failure was ~2600 N for the cements only and ~3800 N for the combination with screws. Two new compositions of magnesium phosphate cements revealed high strength in clinically relevant biomechanical test set-ups and add clinically desired characteristics to its strength such as injectability and drillability.

COMPARISON OF BICONDYLAR TIBIAL PLATEAU FRACTURES WITH DOUBLE OR SINGLE LATERAL LOCKED PLATE

Objective:

To compare postoperative radiographic outcomes of Schatzker type V and VI tibial plateau fractures treated with double-plate or single lateral locked plate.

Methods:

Sixty-three patients operated from December 2011 to February 2016 were selected, 47 from the double-plate group and 16 from the single lateral locked plate group. Minimum follow-up for all patients was 6 months. Fracture reduction evaluation was based on radiographic parameters: joint reduction, sagittal alignment, coronal alignment, and condylar width.

Results:

Radiographic evaluation showed no statistical difference in the immediate or late postoperative periods.

Conclusion:

Despite the reduced sample, this study is aligned with current results published in the medical literature. The severity of Schatzker type V and VI tibial plateau fractures can be minimized by the correct indication for the implant regarding fracture morphology. Level of Evidence III, Retrospective comparative study.

Articular reductions - how close is close enough? A narrative review

Intra-articular fractures are a unique subset of fractures as they involve a varying extent of damage to cartilage. The impact of this articular fracture causes significant microscopic and macroscopic changes, as well as biomechanical irregularities, which can lead to further cartilage damage, and ultimately cascade down the dreaded path to arthritis. It is generally believed that an anatomic reduction of an articular fracture is the necessary goal of treatment for these injuries, however it yet to be delineated how perfect this reduction has to be. A comprehensive literature review was carried out to create a best available evidence guide to the acceptability of upper extremity and lower extremity articular fracture reductions. Ultimately, a perfect anatomic reduction is the best strategy to minimize abnormal loading and wear patterns, however this should be balanced with the realistic factors of each individual case, such as the level of difficulty, joint involved, surgical timing, and patient activity levels.

Impact of breed on canine humeral condylar fracture configuration, surgical management, and outcome

OBJECTIVE

To report the prevalence, configuration, risk factors, fixation methods and outcomes after repair of humeral condylar fractures (HCF) in dogs.

STUDY DESIGN

Retrospective nested cohort study.

SAMPLE POPULATION

One hundred twelve dogs.

METHODS

Medical records of dogs referred between January 2010 and August 2018 were searched for HCF. Demographics, fracture configuration, repair, and complications were obtained from medical records. Radiographs were assessed for fracture reduction, implant positioning, and bone healing. Short-term radiographic and clinical outcomes, and long-term owner-assessed outcome was determined. Associations between these variables were statistically analyzed.

RESULTS

Dogs with HCF represented 112 of 43 325 (0.26%, 95% CI 0.22-0.31) referrals. French bulldogs and spaniel breeds were predisposed to HCF (P < .02). French bulldogs were 6.58 times (95% CI 1.62-26.7) more likely than other breeds to have a medial HCF (P = .008). Epicondylar plate fixation was associated with reduced complications compared with lag screws and Kirschner wires (P = .009). Lameness was scored as 1 of 5 (median) in the 85 dogs with initial follow-up (median 6 weeks) after HCF repair. Outcome was considered excellent in 26 of 31 dogs with long-term follow-up (median 36 months).

CONCLUSION

French bulldogs and spaniels were predisposed to HCF, and medial HCF were more common in French bulldogs. Epicondylar plate fixation was associated with reduced complications.

CLINICAL SIGNIFICANCE

French bulldogs are predisposed to HCF, including medial HCF. Epicondylar plate fixation is recommended over other epicondylar fixation methods to reduce complications.

The effect of coronal splits on the structural stability of bi-condylar tibial plateau fractures: a biomechanical investigation

INTRODUCTION

Surgical treatment of bi-condylar tibial plateau fractures is still challenging due to the complexity of the fracture and the difficult surgical approach. Coronal fracture lines are associated with a high risk of fixation failure. However, previous biomechanical studies and fracture classifications have disregarded coronal fracture lines.

MATERIALS AND METHODS

This study aimed to develop a clinically relevant fracture model (Fracture C) and compare its mechanical behavior with the traditional Horwitz model (Fracture H). Twelve samples of fourth-generation tibia Sawbones were utilized to realize two fracture models with (Fracture C) or without (Fracture H) a coronal fracture line and both fixed with lateral locking plates. Loading of the tibial plateau was introduced through artificial femur condyles to cyclically load the fracture constructs until failure. Stiffness, fracture gap movements, failure loads as well as relative displacements and rotations of fracture fragments were measured.

RESULTS

The presence of a coronal fracture line reduced fracture construct stiffness by 43% (p = 0.013) and decreased the failure load by 38% from 593 ± 159 to 368 ± 63 N (p = 0.016). Largest displacements were observed at the medial aspect between the tibial plateau and the tibial shaft in the longitudinal direction. Again, the presence of the coronal fracture line reduced the stability of the fragments and created increased joint incongruities.

CONCLUSIONS

Coronal articular fracture lines substantially affect the mechanical response of tibia implant structures specifically on the medial side. With this in mind, utilizing a clinically relevant fracture model for biomechanical evaluations regarding bi-condylar tibial plateau fractures is strongly recommended.

Surgical Treatment of Lateral Tibial Plateau Fractures Involving the Posterolateral Column

OBJECTIVE

To summarize the indications and the clinical effects of a transfibular neck osteotomy approach and a combined anterolateral and posterolateral approach in the treatment of fractures of the lateral tibial plateau involving the posterolateral column.

METHODS

Eleven patients with lateral tibial plateau fractures were included in the present study. The fractures were Schatzker type II or lateral platform fractures involving posterolateral column. The anterolateral combined posterolateral approach (lateral + posterolateral locking plate fixation) was applied in 7 patients and 4 patients underwent transfibular neck osteotomy (lateral + posterolateral locking plate fixation + 1/4 tubular plate edge fixation, fibular osteotomy with Kirschner wire tension band fixation, and hollow nail fixation for upper tibiofibular joint). All cases were followed up for 12-24 months, with an average follow-up of 17.5 ± 5.0 months. At the last followup, the Rasmussen radiological criteria were used to evaluate the effect of fracture reduction and fixation. The knee joint function was evaluated using the knee function evaluation criteria of the Hospital for Special Surgery (HSS). The Lachman test and the pivot-shift test were used to evaluate the anterior and posterior and rotational stability of the knee joint. The range of knee motion was recorded.

RESULTS

Bone healing was achieved in all patients with fractures treated with a transfibular neck osteotomy approach and a combined anterolateral and posterolateral approach. At the last follow-up, both the Lachman test and the pivot-shift test results were negative. All patients had complete knee extension. For the combined anterolateral and posterolateral approach, the knee flexion angle was 110°-130°, with an average of 122.86° ± 7.56°. For the transfibular neck osteotomy approach, the knee flexion angle was 115°-130°, with an average of 120.00° ± 7.07°. For the patients in which the combined anterolateral and posterolateral approach was used, the Rasmussen score was 12-18 points, with an average of 16.00 ± 2.56 points. The results were excellent in 4 cases and good in 3 cases; therefore, 100% of results were excellent or good. For patients in which the transfibular neck osteotomy approach was used, the Rasmussen score was 10-18 points, with an average of 15.25 ± 3.77 points. The results were excellent in 2 cases, good in 1 case, and acceptable in 1 case; therefore, 75% of results were excellent or good. The HSS score for the combined anterolateral and posterolateral approach was 76-98 points, with an average of 88.43 ± 7.55 points. The results were excellent in 5 cases and good in 2 cases; therefore, 100% of results were excellent or good. The HSS score for the transfibular neck osteotomy approach was 74-96 points, with an average of 87.25 ± 9.43 points. The results were excellent in 3 cases and good in 1 case; therefore, 100% of results were excellent or good. There were no significant differences in operation time, surgical blood loss, fracture healing time, postoperative imaging score, and knee function evaluation between the two approaches. One patient who underwent transfibular neck osteotomy had a 3-mm step that gradually appeared, but no significant abnormalities were found in the width of the platform and the lower limb force line. One patient in whom the combined anterolateral and posterolateral approach was used showed numbness in the common peroneal nerve. No common peroneal nerve injury occurred through the transfibular neck osteotomy approach.

CONCLUSIONS

The anterolateral combined posterolateral approach and the transfibular neck osteotomy approach are effective in the surgical treatment of lateral tibial plateau fractures involving the posterolateral column. However, the transfibular neck osteotomy approach is more suitable for the posterolateral plateau articular surface damaged with bone separation and displacement, deep collapse, cases involving a large range of the posterolateral column, especially fractures of the lateral tibial plateau in the upper tibiofibular syndesmosis area of the line connecting the anterior and posterior margin of the fibular head to the midpoint of the plateau.

3D printing of implants for patient-specific acetabular fracture fixation: an experimental study

PURPOSE

To test the effect of 3D printed implants, designed according to surgeon's individual plan, on the accuracy of reduction of an acetabular fracture model.

METHODS

Seven identical standardized plastic bone models of an anterior column/posterior hemi-transverse acetabular fracture were used. A CT of one plastic fracture model was made. Using preoperative planning software, three surgeons independently planned the reduction and fixation procedure and designed implants and drill guides. The designed implants and guides were then 3D printed. Each surgeon first executed his plan using his 3D printed plates and guides on one fracture model and then performed another procedure on an identical model with standard implants and instrumentation. Displacement of the fragments at the weight-bearing fracture lines in the acetabulum was measured after fixation. Linear mixed effect models were used to evaluate the effect of different solutions to the same fracture pattern.

RESULTS

Mean (SD) displacement of the fracture line between the ischium and stable fragment was 1.1 (0.9) mm for the standard implant and 0.8 (0.6) mm for the 3D printed implant, while the displacements of the fracture line between the stable fragment and anterior column were 0.6 (0.6) and 0.3 (0.3) for the standard and 3D printed methods, respectively (p < 0.001). Mean (SD) fracture line step-off at any fracture line for the standard implant was 1.2 (0.9) mm and 0.4 (0.4) mm for the 3D printed implant (p = 0.022).

CONCLUSIONS

Patient-specific 3D printed plates and drill guides may facilitate retaining accurate reduction and fixation of select acetabular fracture patterns.

Screen-enrich-combine circulating system to prepare MSC/β-TCP for bone repair in fractures with depressed tibial plateau

Aim: To evaluate the clinical efficacy of mesenchymal stem cell/β-tricalcium phosphate composites (MSC/β-TCP) prepared with a screen-enrich-combine circulating system (SECCS) in patients with depressed tibial plateau fractures. Materials & methods: Bone defects in depressed tibial plateaus were filled with MSC/β-TCP (n = 16) or with β-TCP only (n = 23). Enrichment efficiency and effect of enrichment on cell viability were evaluated. Clinical results were assessed by imaging examination and Lysholm score. Results: SECCS effectively integrated MSCs with β-TCP. At 18 months postimplantation, new bone ratio was significantly higher in patients treated with MSC/β-TCP than in those treated with β-TCP only (p = 0.000). Patients with MSC/β-TCP implants had better functional recovery (p = 0.028). Conclusion: MSC/β-TCP prepared by SECCS were effective in the treatment of bone defects in patients with depressed tibial plateau fractures, promoted bone regeneration and improved joint function recovery.

Biomechanical Evaluation of Promising Different Bone Substitutes in a Clinically Relevant Test Set-Up

(1) Background: Bone substitutes are essential in orthopaedic surgery to fill up large bone defects. Thus, the aim of the study was to compare diverse bone fillers biomechanically to each other in a clinical-relevant test set-up and to detect differences in stability and handling for clinical use. (2) Methods: This study combined compressive strength tests and screw pullout-tests with dynamic tests of bone substitutes in a clinical-relevant biomechanical fracture model. Beyond well-established bone fillers (ChronOS^TM Inject and Graftys^® Quickset), two newly designed bone substitutes, a magnesium phosphate cement (MPC) and a drillable hydrogel reinforced calcium phosphate cement (CPC), were investigated. (3) Results: The drillable CPC revealed a comparable displacement of the fracture and maximum load to its commercial counterpart (Graftys^® Quickset) in the clinically relevant biomechanical model, even though compressive strength and screw pullout force were higher using Graftys^®. (4) Conclusions: The in-house-prepared cement allowed unproblematic drilling after replenishment without a negative influence on the stability. A new, promising bone substitute is the MPC, which showed the best overall results of all four cement types in the pure material tests (highest compressive strength and screw pullout force) as well as in the clinically relevant fracture model (lowest displacement and highest maximum load). The low viscosity enabled a very effective interdigitation to the spongiosa and a complete filling up of the defect, resulting in this demonstrated high stability. In conclusion, the two in-house-developed bone fillers revealed overall good results and are budding new developments for clinical use.

Surgical Management of Displaced Intra-Articular Calcaneal Fractures: What Matters Most?

Displaced intra-articular calcaneal fractures are severe, complex injuries that can cause significant long-term functional impairment. Despite the controversies of whether these fractures should be treated operatively or nonoperatively, functional improvement can be seen with confounding variables that can be controlled by the surgeon. This article reviews prognostic factors that are associated with good functional outcomes following operatively treated displaced intra-articular calcaneal fractures.

Articular Incongruity in the Lower Extremity: How Much Is Too Much?

Intraarticular fractures carry a significant risk for posttraumatic osteoarthritis, and this risk varies across different joint surfaces of the lower extremity. These differences are likely due to the anatomic and biomechanical specifics of each joint surface. High-quality human studies are lacking to delineate the threshold articular incongruity that significantly increases risk for posttraumatic osteoarthritis and diminished clinical outcomes for many joint surfaces. Even with anatomic reduction of the articular surface, close attention must be paid to mechanical axis and joint stability to optimize outcomes.

Incidence, Risk Factors, and Location of Articular Malreductions of the Tibial Plateau

OBJECTIVES

To define the incidence, risk factors, and anatomic location of articular malreductions in operatively treated lateral tibial plateau fractures.

DESIGN

Prospective Cohort Study.

SETTING

Academic Level 1 Trauma Centre.

PATIENTS/PARTICIPANTS

Study subjects were patients entered into a prospective cohort study of tibial plateau fractures.

INTERVENTIONS

Surgical fixation of tibial plateau fractures and postoperative computed tomographies (CTs).

MAIN OUTCOME MEASURES

The primary outcome was incidence of articular malreduction. Secondary outcomes included risk factors for malreduction and a descriptive analysis of malreduction location.

RESULTS

Sixty-five postoperative CTs were reviewed. Twenty-one reductions (32.3%) had a step or gap more than 2 mm. The frequency of malreductions in patients undergoing submeniscal arthrotomy or fluoroscopic-assisted reduction alone was 16.6% and 41.4%, respectively (P = 0.0021). Age, body mass index, OTA/AO fracture type, operative time, use of bone graft or bone graft substitute, and use of locking plates were not predictive of malreduction. Malreductions were heavily weighted to the posterior quadrants of the lateral tibial plateau.

CONCLUSIONS

When examined using cross-sectional imaging the rate of articular malreductions was high at 32.3%. Fluoroscopic reduction alone was a predictor for articular malreduction. Most malreductions were located in the posterior quadrants of the lateral plateau.

LEVEL OF EVIDENCE

Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Is Early Definitive Fixation of Bicondylar Tibial Plateau Fractures Safe? An Observational Cohort Study

OBJECTIVES

The optimal treatment protocol for bicondylar plateau fractures remains controversial. Contrary to popular practice which favors a staged protocol in many high-energy fracture patterns, we have used early single-stage open reduction and internal fixation (ORIF) to treat these injuries whenever possible. The purpose of this study was to determine the complication rate and the functional and radiographic outcomes of this strategy.

DESIGN

Retrospective cohort study and prospective data collection.

SETTING

Level I trauma center.

PATIENTS/PARTICIPANTS

One hundred one patients with 102 OTA/AO type 41-C bicondylar tibial plateau fractures were treated with early definitive ORIF, defined as nonstaged surgery performed within 72 hours from injury. A subset of patients was part of a longitudinal study and reported functional outcomes at 1 year.

INTERVENTION

Early definitive ORIF.

MAIN OUTCOME MEASUREMENT

Primary outcome: reoperation rate, defined as any surgery within 12 months after the index operation; secondary outcomes: quality and stability of radiographic fracture reduction; and functional outcome [Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) and short musculoskeletal functional assessment (SMFA)].

RESULTS

Nonstaged operative treatment of bicondylar plateau fractures was performed in 91.3% of the fractures during the study period. For those, early definitive ORIF (surgery within 72 hours from injury) was performed in 82.3% fractures. Mean time from injury to ORIF, for closed fractures, was 29.8 hours. Sixteen (15.7%) fractures, which were treated with early definitive ORIF, required an additional surgical procedure within 12 months. Complications included wound infection requiring surgical management, compartment syndrome requiring fasciotomies, nonunion, early fixation failure, and implant removal for discomfort. The reoperation rate was 12.7% if implant removal was excluded. At least 3 of the 4 radiographic criteria used to assess the adequacy of reduction were achieved in 95.1% of cases, and all 4 criteria were met in 59.8% of fractures. The Physical Component of the SF-36 at 12 months was 42.6, which is comparable to values reported in previous studies for operative treatment of bicondylar plateau fractures.

CONCLUSIONS

In a model where surgery is performed without delay by experienced orthopaedic trauma surgeons, a large proportion of bicondylar tibial plateau fractures can be safely treated with early definitive ORIF. Early surgery was associated with satisfactory postoperative radiographic reductions.

LEVEL OF EVIDENCE

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

Is the AO guideline for postoperative treatment of tibial plateau fractures still decisive? A survey among orthopaedic surgeons and trauma surgeons in the Netherlands

INTRODUCTION

The standard aftercare treatment (according to the AO guideline) for surgically treated trauma patients with fractures of the tibial plateau is non-weight bearing or partial weight bearing for 10-12 weeks. The purpose of this study was to investigate the current state of practice among orthopaedic surgeons and trauma surgeons in choosing the criteria and the time period of restricted weight bearing after surgically treated tibial plateau fractures.

MATERIALS AND METHODS

A web-based survey was distributed among members of the Dutch Trauma Society and Dutch Orthopaedic Society to identify the most commonly applied protocols in terms of the post-operative initiation and level of weight bearing in patients with tibial plateau fractures.

RESULTS

One hundred and eleven surgeons responded to the survey. 72.1% of the respondents recommended starting weight bearing earlier than the 12 weeks recommended by the AO guideline; 11.7% recommended starting weight bearing immediately, 4.5% after 2 weeks and 55.9% after 6 weeks. Moreover, 88.7% of the respondents reported deviating from their own local protocol. There is little consensus about the definition of 100% weight bearing and how to build up weight bearing over time.

CONCLUSION

This study demonstrates that consensus about the weight bearing aftercare for tibial plateau fractures are limited. A large majority of surgeons do not follow the AO guideline or their own local protocol. More transparent criteria and predictors are needed to design optimal weight-bearing regimes for the aftercare of tibial plateau fractures.

Sport and early osteoarthritis: the role of sport in aetiology, progression and treatment of knee osteoarthritis

Sports activities are considered favourable for general health; nevertheless, a possible influence of sports practice on the development of early osteoarthritis (OA) is a cause for concern. A higher incidence of OA in knees and ankles of former high-impact sports players than in those of the normal population has been shown and it is still debatable whether the cause is either to be recognized generically in the higher number of injuries or in a joint overload. The possibility to address knee OA in its early phases may be strictly connected to the modification of specific extrinsic or intrinsic factors, related to the patient in order to save the joint from further disease progression; these include sport practice, equipment and load. Non-surgical therapies such as continuative muscles reinforce and training play a strong role in the care of athletes with early OA, particularly if professional. There is an overall agreement on the need of an early restoring of a proper meniscal, ligament and cartilage integrity in order to protect the knee and resume sports safely, whereas alignment is a point still strongly debatable especially for professional athletes. Remaining questions still to be answered are the risks of different sports in relation to one another, although an actual protective effect of low-impact sports, such as walking, swimming or cycling, has been recognized on the appearance or worsening of OA, the effect of continuing or ceasing to practice a sport on the natural history of early OA, and even following appropriate treatment is still unknown.

Dance between biology, mechanics, and structure: A systems-based approach to developing osteoarthritis prevention strategies

Osteoarthritis (OA) is a leading cause of human suffering and disability for which disease-modifying treatments are lacking. OA occurs through complex and dynamic interplays between diverse factors over long periods of time. The traditional research and clinical focus on OA, the end stage disease, obscured understanding pathogenesis prior to reaching a common pathway defined by pain and functional deficits, joint deformity, and radiographic changes. To emphasize disease modification and prevention, we describe a multi-disciplinary systems-based approach encompassing biology, mechanics, and structure to define pre-osteoarthritic disease processes. Central to application of this model is the concept of "pre-osteoarthritis," conditions where clinical OA has not yet developed. Rather, joint homeostasis has been compromised and there are potentially reversible markers for heightened OA risk. Key messages from this perspective are (i) to focus research onto defining pre-OA through identifying and validating biological, mechanical, and imaging markers of OA risk, (ii) to emphasize multi-disciplinary approaches, and (iii) to propose that developing personalized interventions to address reversible markers of OA risk in healthy joints may be the key to prevention. Ultimately, a systems-based analysis of OA pathogenesis shows potential to transform clinical practice by facilitating development and testing of new strategies to prevent or delay the onset of osteoarthritis.

Clinical and functional outcomes after operative management of Salter-Harris III and IV fractures of the proximal tibial epiphysis

Pediatric proximal tibial epiphysis fractures are uncommon and have subsequently received little attention in terms of treatment and outcomes. We studied the clinical and functional outcomes of 13 patients with Salter-Harris III and IV fractures of the proximal tibial epiphysis after operative fixation. Associated meniscus, ligamentous, or neurovascular injury was present in 100% of this cohort. Provisional external fixation and locked plating spanning the open physis were used in the majority of cases. The mean clinical follow-up was 15.69 months, where all fractures progressed to union. Good functional outcomes with a low complication rate are possible after operative fixation of these infrequent injuries.

Second-look arthroscopy after surgical treatment of Schatzker type II plateau fractures through the lateral submeniscal approach

MAIN PROBLEM

To evaluate cartilage healing using second-look arthroscopic examination in tibia plateau fracture patients who have undergone open reduction and internal fixation with a submeniscal approach technique.

METHODS

Between January 2007 and January 2010, we used second-look arthroscopy during 18-24-month follow-up of 20 patients with Schatzkar type II tibial plateau fractures who had undergone open reduction and internal fixation with a submeniscal approach technique. We classified patients according to step-off, knee range of motion, and Knee Society Score, and compared the results with those obtained by arthroscopy.

RESULTS

Radiologically, 16 cases (80 %) were reduced within 2 mm of step-off. In 11 of these cases, according to the Outerbridge classification, we checked for chondromalacia from grade II to III. We observed 2 mm of step-off in four cases, and each had chondromalacia of at least grade III. The Knee Society Score was associated with chondromalacia grade (p < 0.05).

CONCLUSION

Even in patients with normal joint range of motion and good clinical and radiological results, the actual condition of the articular cartilage varied significantly. Therefore, more long-term and regular follow-up is needed for proximal plateau fractures.

Collecting a comprehensive evidence base to monitor fracture rehabilitation: A case study

AIM: To determine the feasibility and potential role of combining radiostereometric analysis (RSA), gait analysis and activity monitoring in the follow-up of fracture patients.

METHODS: Two patients with similar 41B3 tibial plateau fractures were treated by open reduction internal fixation augmented with impaction bone grafting and were instructed to partial weight bear to 10 kg for the first six postoperative weeks. Fracture reduction and fixation were assessed by postoperative computer tomographic (CT) scanning. Both patients had tantalum markers inserted intra-operatively to monitor their fracture stability during healing using RSA and differentially loaded RSA (DLRSA) at 6 and 12 wk postoperatively. Gait analyses were performed at 1, 2, 6, and 12 wk postoperatively. Activity monitors were worn for 4 wk between the 2 and 6 wk appointments. In addition to gait analysis, knee function was assessed using the patient reported Lysholm scores, and doctor reported knee range of motion and stability, at 6 and 12 wk postoperatively.

RESULTS: There were no complications. CT demonstrated that both fractures were reduced anatomically. Gait analysis indicated that Patient 1 bore weight to 60% of body weight at 2 wk postoperative and 100% at 6 wk. Patient 2 bore weight at 10% of body weight to 6 wk and had very low joint contact forces to that time. At 12 wk however, there was no difference between the gait patterns in the two patients. Patient 1 increased activities of moderate-vigorous intensity from 20 to 60 min/d between 2 and 6 postoperative weeks, whereas Patient 2 remained more stable at 20-30 min/d. The Lysholm scores were similar for both patients and did not improve between 6 and 12 wk postoperatively. DLRSA examination at 12 wk showed that both patients were comfortable to weight bear to 80 kg and under this weight the fractures displaced less than 0.4 mm. RSA measurements demonstrated over time fracture migrations of less than 2 mm in both cases. However, Patient 2, who followed the postoperative weight bearing instructions most closely, displaced less (0.3 mm vs 1.6 mm).

CONCLUSION: This study demonstrates the potential of using a combination of RSA, gait analysis and activity monitoring to obtain a comprehensive evidence base for postoperative weight bearing schedules during fracture healing.

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.

A comparative biomechanical study for complex tibial plateau fractures: nailing and compression bolts versus modern and traditional plating

AIM

To compare the biomechanical properties of a newly proposed technique, utilizing intramedullary nailing and compression bolts, for the osteosynthesis of intra-articular proximal tibial fractures with meta-diaphyseal comminution, with modern and conventional plating techniques.

METHODS

Fifteen left tibia 4th generation composite Sawbones models (in 3 groups of 5 for each technique) with identically reproduced type VI Schatzker tibial plateau fractures, including meta-diaphyseal dissociation, were used. Three different techniques of osteosynthesis were tested: (a) a new technique that combines intramedullary nailing and compression bolts, (b) internal fixation with a single lateral locking plate and (c) internal fixation with dual buttress plating technique. The model-device constructs were successively subjected to 500N, 1000N and 1500N load levels with five cycles applied at each level on both articular compartments and a final load cycle to failure. Four parameters were recorded for each technique: the average reversible or irreversible displacement in vertical subsidence, the horizontal diastasis of the intra-articular fracture, the average passive construct stiffness and the load to failure.

RESULTS

The new intramedullary nailing technique provided rigid intra-articular osteosynthesis being statistically similar to dual buttress plating for subsidence at medium and higher load levels. At the same time the proposed technique provided statistically equivalent stiffness values to the single lateral locking plate incarnating the rational of biologic fixation. Average load to failure was 1611N for single lateral locking plates, 2197N for intramedullary nailing and 4579N for dual buttress plating. The single lateral locking plate technique had the worse results in interfragmentary displacement while dual buttress plating was superior in stiffness from the other 2 techniques. The mode of failure differed between techniques, with collapse of medial plateau occurring exclusively in the single lateral locking plates group.

CONCLUSION

The proposed new technique of intramedullary nailing and compression bolts demonstrates a flexural behaviour similar to single lateral locking plates, which complies with the terms and benefits of biological fixation, while at the same time maintains a rigid intra-articular stability similar to the stiff dual buttressing plating technique.

A biomechanical study comparing two fixation methods in depression fractures of the lateral tibial plateau in porcine bone

Background

A novel method of fixation has been described for the treatment of pure depression fractures of the lateral tibial plateau. Fracture fragments are elevated through a reamed transtibial tunnel. An interference screw is then passed into the tunnel to buttress fracture fragments from beneath. This method of fixation has perceived benefits but there have been no studies to demonstrate that the technique is biomechanically sound. The aim of our study is to compare traditional parallel, subchondral screw fixation with the use of an interference screw, assessing maintenance of fracture reduction following simulated post-operative loading, and overall construct strength.

Methods

Depression fractures of the lateral tibial plateau were simulated in 14 porcine knees. Fracture fragments were elevated through a reamed transtibial tunnel and samples were randomly assigned to a fixation method. 7 knees underwent traditional fixation with parallel subcortical cannulated screws, the remainder were stabilized using a single interference screw passed through the transtibial tunnel. Following preloading, each tibia was cyclically loaded from 0 to 500 Newtons for 5,000 cycles using a Nene testing machine. Displacement of the depressed fracture fragments were measured pre and post loading. Samples were then loaded to failure to test ultimate strength of each construct.

Results

The depression displacement of the fractures fixed using cannulated screws was on average 0.76 mm, in comparison to 0.61mm in the interference screw group (p=0.514). Mechanical failure of the cannulated screw constructs occurred at a mean of 3400 N. Failure of the transtibial interference screw constructs occurred at a mean of 1700 N (p<0.01). In both groups the mechanism of ultimate failure was splitting of the tibial plateau.

Conclusion

These results demonstrate the increased biomechanical strength of parallel, cannulated screws for depression fractures of the tibial plateau, however the use of a transtibial interference screw may be a viable method of fixation under physiological loads.

Use of bone graft substitutes in the management of tibial plateau fractures

The current available evidence for the use of bone graft substitutes in the management of subchondral bone defects associated with tibial plateau fractures as to their efficiency and safety has been collected following a literature review of the Ovid MEDLINE (1948-Present) and EMBASE (1980-Present). Nineteen studies were analysed reporting on 672 patients (674 fractures), with a mean age of 50.35 years (range 15-89), and a gender ratio of 3/2 males/females. The graft substitutes evaluated in the included studies were calcium phosphate cement, hydroxyapatite granules, calcium sulphate, bioactive glass, tricalcium phosphate, demineralised bone matrix, allografts, and xenograft. Fracture healing was uneventful in over 90% of the cases over a variant period of time. Besides two studies reporting on injectable calcium phosphate cement excellent incorporation was reported within 6 to 36 months post-surgery. No correlation was made by any of the authors between poor incorporation/resorption and adverse functional or radiological outcome. Secondary collapse of the knee joint surface ≥ 2 mm was reported in 8.6% in the biological substitutes (allograft, DBM, and xenograft), 5.4% in the hydroxyapatite, 3.7% in the calcium phosphate cement, and 11.1% in the calcium sulphate cases. The recorded incidence of primary surgical site and donor site infection (3.6%) was not statistically significant different, however donor site-related pain was reported up to 12 months following autologous iliac bone graft (AIBG) harvest. Shorter total operative time, greater tolerance of early weight bearing, improved early functional outcomes within the first year post-surgery was also recorded in the studies reporting on the use of injectable calcium phosphate cement (Norian SRS). Despite a lack of good quality randomised control trials, there is arguably sufficient evidence supporting the use of bone graft substitutes at the clinical setting of depressed plateau fractures.

Bone graft substitutes for articular support and metaphyseal comminution: what are the options?

Subchondral and metaphyseal bone defects pose a great challenge for the Orthopaedic surgeon not only because the support for the articular surface has been lost but also because the mechanism for the nourishment of articular cartilage through the subchondral plate is distorted. A number of options are available to the surgeons, none of them perfect. Autografting has an appreciable high rate of harvest site morbidity, allograft is associated with infection transmission and host immunologic response. These realities have stimulated interest in supplying bone replacement materials (demineralised bone matrix, synthetic bone substitutes, bone morphogenic proteins). This paper presents the indications and applications of bone substitutes for metaphyseal defects and subchondral support in orthopaedic trauma.

Sagittal plane deformity in bicondylar tibial plateau fractures

OBJECTIVE

To evaluate the prevalence and magnitude of sagittal plane deformity in bicondylar tibial plateau fractures.

DESIGN

Retrospective radiographic review.

SETTING

Two Level I trauma centers.

MAIN OUTCOME MEASUREMENT

Sagittal inclination of the medial and lateral plateau measured in relation to the longitudinal axis of the tibia using computed tomographic reconstruction images.

PATIENTS

Seventy-four patients (mean age, 49 years; range, 16-82 years; 64% male) with acute bicondylar tibial plateau fractures (Orthopaedic Trauma Association 41C, Schatzker VI) treated from October 2006 to July 2009.

RESULTS

The average sagittal plane angulation of the lateral plateau was 9.8° posteriorly (range, 17° anteriorly to 37° posteriorly). The medial plateau was angulated 4.1° posteriorly on average (range, 16° anteriorly to 31° posteriorly). Forty-two lateral plateaus were angulated more than 5° from the "normal" anatomic slope (defined as 5° of posterior tibial slope). Of these, 76% were angulated posteriorly. Forty-three (58%) of the medial plateaus were angulated greater than 5° from normal, of which only 47% were inclined posteriorly (P = 0.019 compared with lateral plateaus). In 68% of patients, the difference between medial and lateral plateaus was greater than 5°; the average intercondylar slope difference was 9° (range, 0°-31°; P < 0.001). Spanning external fixation did not affect the slope of either the medial or lateral tibial plateau. Intraobserver and interobserver correlations were high for both the medial and lateral plateaus (r > 0.81, P < 0.01).

CONCLUSIONS

Considerable sagittal plane deformity exists in the majority of bicondylar tibial plateau fractures. The lateral plateau has a higher propensity for sagittal angulation and tends to have increased posterior slope. Most patients have a substantial difference between the lateral and medial plateau slopes. The identification of this deformity allows for accurate preoperative planning and specific reduction maneuvers to restore anatomic alignment.

Weight-bearing-induced displacement and migration over time of fracture fragments following split depression fractures of the lateral tibial plateau: a case series with radiostereometric analysis

We investigated the stability of seven Schatzker type II fractures of the lateral tibial plateau treated by subchondral screws and a buttress plate followed by immediate partial weight-bearing. In order to assess the stability of the fracture, weight-bearing inducible displacements of the fracture fragments and their migration over a one-year period were measured by differentially loaded radiostereometric analysis and standard radiostereometric analysis, respectively. The mean inducible craniocaudal fracture fragment displacements measured -0.30 mm (-0.73 to 0.02) at two weeks and 0.00 mm (-0.12 to 0.15) at 52 weeks. All inducible displacements were elastic in nature under all loads at each examination during follow-up. At one year, the mean craniocaudal migration of the fracture fragments was -0.34 mm (-1.64 to 1.51). Using radiostereometric methods, this case series has shown that in the Schatzker type II fractures investigated, internal fixation with subchondral screws and a buttress plate provided adequate stability to allow immediate post-operative partial weight-bearing, without harmful consequences.

Assessment of two 3-D fluoroscopic systems for articular fracture reduction: a cadaver study

OBJECTIVE

The most commonly used imaging device for assessment of fracture reduction is the two-dimensional X-ray fluoroscope. Two recently introduced 3D fluoroscopic devices, the Siremobil ISO-C3D (Siemens) and the C-InSight (Mazor Surgical Technologies), enable the surgeon to obtain spatial information for the assessment of articular reduction and hardware placement. The purpose of this study was to assess the reliability and accuracy of these two 3D fluoroscopic systems in measuring articular reduction in a cadaveric tibial plateau fracture.

METHODS

Six cadaveric knee specimens were osteotomized at the lateral tibial plateau and fixed with a maximal articular step-off of 0, 1, 2.5, 5 and 7.5 mm. Each specimen was scanned 10 times with two 3D fluoroscopes, the Siremobil ISO-C3D and the C-InSight. The resulting images were reformatted and interpreted for articular displacements at four different locations at the plateau level and were compared with high-resolution CT scans by an independent observer.

RESULTS

For the non-displaced fracture, no displacement (mean < 0.1 mm) was observed in either modality. The mean scanning time for the ISO-C3D was 2 min, while each C-InSight scan took 20 s. The readings at four different points along the malreduced fractures were similar for most measurements with either of the two modalities. The C-InSight readings were less accurate than those of the ISO-C3D, relative to the CT scan, but most errors were within clinically acceptable limits (< 2 mm) and used less radiation.

CONCLUSIONS

Intraoperative 3D fluoroscopes can detect clinically significant intra-articular step-off with acceptable measurement errors, using newer devices that enable the use of a conventional C-arm and reduced radiation.

Lateral ankle radiographs: do we really understand what we are seeing?

OBJECTIVES

To evaluate the validity of using lateral intraoperative fluoroscopic imaging to assess the reduction of the tibial plafond articular surface, two hypotheses were tested: 1) the distal tibial subchondral shadow on the lateral ankle radiograph is created equally by the medial, central, and lateral portions of the distal tibia; and (2) displacement of a 5-mm width osteochondral fragment is consistently recognizable on lateral fluoroscopic imaging.

METHODS

Six human fresh-frozen tibial plafond cadaveric specimens were sagitally sectioned in 5-mm increments after removal of the anterior soft tissue and stabilization of the position of the ankle through external fixation. To test the first hypothesis, a perfect lateral radiograph was taken after sectioning the specimens. The sagittal sections were then removed sequentially from medial to lateral. A perfect lateral radiograph was taken after each change. The sagittal sections were then removed beginning laterally and moving medially. A perfect lateral radiograph was taken after each change. The images were then compared with specific evaluation of the change in the subchondral shadow density. To test the second hypothesis, three malreductions were created by displacing a 5-mm osteochondral segment. After each malreduction, a perfect lateral radiograph was saved. These saved fluoroscopic images were placed in random order with lateral images of normal specimens. Four experienced ankle surgeons were then asked to determine whether the radiographs revealed displacement. Inter- and intraobserver reliability was then evaluated.

RESULTS

First, the subchondral shadow of the distal tibia appears to be created by an equal confluence of the subchondral bone of the medial, central, and lateral aspects of the tibial plafond. Second, fellowship-trained observers experienced in pilon fracture treatment correctly identified malreduction only 45% of the time. Intraclass correlation coefficient revealed very poor interobserver reliability with an alpha reliability statistic of 0.183. Intraobserver reliability across all four observers yielded an alpha statistic of 0.474, indicating inconsistencies in observers' evaluation of identical images at separate viewings.

CONCLUSIONS

It is difficult to discern rotational or translational displacement of a 5-mm osteochondral fragment on a perfect lateral fluoroscopic view of the ankle. Even with what appears to be a perfect lateral fluoroscopic view intraoperatively, displacement may still be present. When small osteochondral fragments are present, direct visualization of the articular surface is necessary to confidently establish that an anatomic reduction has been achieved.

ASB Clinical Biomechanics Award Paper 2010 Virtual pre-operative reconstruction planning for comminuted articular fractures

BACKGROUND

Highly comminuted intra-articular fractures are complex and difficult injuries to treat. Once emergent care is rendered, the definitive treatment objective is to restore the original anatomy while minimizing surgically induced trauma. Operations that use limited or percutaneous approaches help preserve tissue vitality, but reduced visibility makes reconstruction more difficult. A pre-operative plan of how comminuted fragments would best be re-positioned to restore anatomy helps in executing a successful reduction.

METHODS

In this study, the methods for virtually reconstructing a tibial plafond fracture were developed and applied to clinical cases. Building upon previous benchtop work, novel image analysis techniques and puzzle solving algorithms were developed for clinical application. Specialty image analysis tools were used to segment the fracture fragment geometries from CT data. The original anatomy was then restored by matching fragment native (periosteal and subchondral) bone surfaces to an intact template, generated from the uninjured contralateral limb.

FINDINGS

Virtual reconstructions obtained for ten tibial plafond fracture cases had average alignment errors of 0.39 (0.5 standard deviation) mm. In addition to precise reduction planning, 3D puzzle solutions can help identify articular deformities and bone loss.

INTERPRETATION

The results from this study indicate that 3D puzzle solving provides a powerful new tool for planning the surgical reconstruction of comminuted articular fractures.

Is elevated contact stress predictive of post-traumatic osteoarthritis for imprecisely reduced tibial plafond fractures?

Despite the widely held belief that residual incongruities from intra-articular fractures subject the joint to contact stresses that predispose to post-traumatic osteoarthritis (PTOA), objective evidence has been lacking. This study tested the hypothesis that a metric of elevated contact stress exposure would predict the onset of PTOA. The ankles of 10 tibial plafond fracture patients were treated initially using a spanning fixator, with subsequent screw fixation of the articular surface. Following up on an earlier report of finite element computed post-operative contact stress distributions in these patients' ankles, Kellgren-Lawrence (KL) scores were assessed from minimum 2-year follow-up radiographs to characterize the presence/severity of PTOA. At that time point, seven patients had developed PTOA (KL ≥ 2). Five different metrics of contact stress exposure were calculated, all of which exhibited excellent concordance with KL scores, ranging from 88% to 95%. When time of stress exposure was included, one metric was able to predict PTOA development (KL ≥ 2) with 100% reliability, and all metrics exhibited >94% prediction reliability. These findings, albeit in a small population, support the existence of a contact stress exposure threshold above which incongruously reduced tibial plafond fractures are highly likely to develop PTOA.