Correlation between CT images of lateral plateau and lateral meniscus injuries in patients with Schatzker II tibial plateau fractures:a retrospective study

Background There is a great deal of controversy on whether routine MRI examination is needed for fresh fractures while the vast majority of patients with tibial plateau fractures (TPFs) receive preoperative X-ray and CT examinations. The purpose of the study was to analyze the exact correlation between CT images of lateral plateau and lateral meniscus injuries in Schatzker II TPFs. Methods A total of 296 patients with Schatzker II TPFs from August 2012 to January 2021 in two trauma centers were enrolled for the analysis. According to the actual situation during open reduction internal fixation (ORIF) and knee arthroscopic surgery, patients were divided into meniscus injury (including rupture, incarceration, etc.) and non-meniscus injury groups. The values of both lateral plateau depression (LPD) and lateral plateau widening (LPW) of lateral tibial plateau on CT images were measured, and their correlation with lateral meniscus injury was then analyzed. The relevant receiver operating characteristic (ROC) curve was drawn to evaluate the optimal cut-off point of the two indicators which could predict meniscus injury. Results The intra- and inter-observer reliabilities of LPD and LPW were acceptable (intraclass correlation coefficient (ICC) > 0.8). The average LPD was 13.2 ± 3.2 mm while the average value of the group without meniscus injury was 9.4 ± 3.2 mm. The difference between the two groups was statistically significant (P < 0.05). The average LPW was 8.0 ± 1.4 mm and 6.8 ± 1.6 mm in meniscus injury and non-meniscus injury groups with a significant difference (P < 0.05). The optimal predictive cut-off value of LPD and LPW was 7.9 mm (sensitivity-95.0%, specificity-58.8%, area under the curve (AUC-0.818) and 7.5 mm (sensitivity-70.0%, specificity - 70.6%, AUC - 0.724), respectively. The meniscus injury group mainly showed injuries involving the mid-body and posterior horn of lateral meniscus (98.1%, 157/160). Conclusions The mid-body and posterior horn of lateral meniscus injury is more likely to occur in patients with Schatzker II TPFs when LPD > 7.9 mm and/or LPW > 7.5 mm on CT. These findings will definitely provide guidance for orthopedic surgeons in treating such injuries. During the operation, more attention is required be paid to the treatment of the meniscus and the possible fracture reduction difficulties and poor alignment caused by meniscus rupture and incarceration should be fully considered in order to achieve better surgical results.

Biomechanical Study on the Stress Distribution of the Knee Joint After Distal Femoral Fracture Malunion With Residual Varus-valgus Deformity

BackgroundThis study aims to examine the biomechanical influence of residual varus and valgus deformity after malunion of distal femoral fractures on the knee joint. MethodsWe selected 14 adult cadaver specimens to establish the femoral fractures models and subsequently fixed them at neutral position and malunion positions, i.e. at 3°, 7° and 10° at valgus and varus positions, respectively. Ultra-low pressure sensitive film technology was used to quantitatively measure the stress distribution on the medial and lateral plateau of the tibia.ResultsAt neutral position, with 400 N vertical load applied, the stress values of the medial and lateral plateau of tibia were 1.162±0.114 MPa and 1.103±0.144 MPa, respectively. Compared with those measured at neutral position, the stress on the medial plateau of the valgus tibia significantly increased, while that on the lateral plateau of the valgus tibia significantly decreased (both P<0.05). In contrast, the stress on the lateral plateau of the valgus tibia significantly increased, while that on the medial plateau of the valgus tibia significantly decreased (both P<0.05). The medial plateau of tibia demonstrated significantly higher stress values than those on the lateral plateau at neutral position and 3°, 7°, 10° varus deformities, respectively (all P<0.05), but showed significantly lower values than the those on the lateral plateau at 3°, 7°, 10° valgus deformities, respectively (all P<0.05). ConclusionsThe residual varus and valgus deformities after mulunion of the distal femoral fracture resulted in significant changes of the stress distribution of the knee joint. Anatomical reduction and firm fixation of distal femoral fracture should be as possible to be obtained to avoid possible varus and valgus deformities.

Correlation Between CT Images of Lateral Plateau and Lateral Meniscus Injuries in Patients With Schatzker II Tibial Plateau Fractures：A Retrospective Study

Background: There is a great deal of controversy on whether routine MRI examination is needed for fresh fractures while the vast majority of patients with tibial plateau fractures receive preoperative X-ray and CT examinations. The purpose of the study was to analyze the exact correlation between CT images of lateral plateau and lateral meniscus injuries in Schatzker II tibial plateau fractures. Methods: Two hundred and ninety-six Schatzker II tibial plateau fracture patients from August 2012 to January 2021 in two trauma centers were enrolled for the analysis. According to the actual situation during open reduction internal fixation (ORIF) and knee arthroscopic surgery, patients were divided into meniscus injury (including rupture, incarceration, etc.) and non-meniscus injury groups. By measuring the value of both lateral plateau depression (LPD) and lateral plateau widening (LPW) of lateral tibial plateau on the coronary CT images, the correlation of which and lateral meniscus injury was analyzed. Meanwhile, the relevant receiver operating characteristic (ROC) curve was drawn to evaluate the optimal operating point of these two indicators which could predict meniscus injury. Results: Meniscus injury group mainly showed injuries involving the mid-body and posterior horn of the meniscus (98.1%, 157/160). The average LPD was 13.2 ± 3.2 mm, while the average value of the group without meniscus injury was 9.4 ± 3.2 mm. The difference was statistically significant (P < 0.05). The average LPW was 8.0 ± 1.4 mm and 6.8 ± 1.6 mm in two groups with a significant difference (P < 0.05). The optimal operating point of LPD and LPW was 7.9 mm (sensitivity-95.0%, specificity-58.8%, area under the curve (AUC-0.818) and 7.5 mm (sensitivity-70.0%, specificity-70.6%, AUC-0.724), respectively. Conclusions: The mid-body and posterior horn of lateral meniscus injury is more likely to occur in patients who had Schatzker II tibial plateau fractures when LPD > 7.9 mm and/or LPW > 7.5 mm on CT manifestations and these findings will definitely provide guidance for orthopedic surgeons in treating such injuries. During the operation, more attention should be paid to the treatment of the meniscus and full consideration is needed be taken to situations such as meniscus rupture, incarceration and other possible fracture reduction difficulties, poor vertical line, etc., in order to achieve better surgical results.

A Cadaveric Anatomical Study of the Relationship between Proximal Tibial Slope and Coronal Plane Deformity

Medial proximal tibial angle (MPTA) and posterior proximal tibial angle (PPTA) are commonly used to characterize the geometry of proximal tibia and are important considerations in lower extremity realignment procedures and total knee arthroplasty. This study utilized a large cadaveric collection to explore relationships between tibial slope and coronal plane deformity of the tibia. We utilized 462 well-preserved skeletons (924 tibiae), excluding any with fracture or obvious rheumatologic or infectious findings. Custom cards were made with different sized arcs on the bottom surface, so that they could rest on the anterior and posterior aspects of the medial and lateral tibial plateaus of each bone to measure PPTA. Previously measured MPTA values for the same bones were also utilized. Multiple regression analysis was used to determine relationship between MPTA and medial and lateral PPTAs. The mean age was 56 ± 10 years, with 13% female and 31% African American (remainder Caucasian). The mean MPTA was 87.2 ± 2.4 degrees. The mean medial plateau PPTA was 81.5 ± 3.8 degrees and mean lateral plateau PPTA was 81.3 ± 3.7 degrees. Regression analysis found that MPTA was significantly associated with both medial and lateral PPTAs (standardized betas 0.197 and 0.146, respectively, p < 0.0005 for both). There was a significant correlation between lateral and medial PPTAs (r = 0.435, p = 0.03). The clinical significance of these findings warrants further investigation and emphasizes the importance of carefully assessing the sagittal plane when planning reconstruction of a tibia with varus or valgus deformity, particularly high tibial osteotomies.

Lateral Tibial Plateau with Peroneal Nerve Entrapment is Unique Fracture in Diagnosis and Management

A majority of tibial plateau fractures involve the lateral plateau. Posterolateral tibial plateau fractures are caused by a valgus force that impacts the posterolateral plateau against the lateral femoral condyle. We describe a unique case of a patient who sustained a lateral plateau fracture with posterior displacement behind a fractured fibular head, with entrapment of the peroneal nerve. This unusual fracture pattern required dual anterolateral and lateral approach for reduction and fixation.

Biomechanical study on the stress distribution of the knee joint after distal femoral fracture malunion with residual varus-valgus deformity

Background: To investigate the effect of residual varus and valgus deformity on the stress distribution of knee joint after distal femoral fracture malunion. Methods: Fourteen adult cadaver specimens with formalin were selected to establish the femoral fractures models, which were fixed subsequently at neutral position (anatomical reduction) and malunion positions (at 3 degrees, 7 degrees, 10 degrees valgus positions and 3 degrees, 7 degrees, and 10 degrees varus positions). The stress distribution on the medial and lateral plateau of the tibia was quantitatively measured using ultra-low pressure sensitive film technology. The change of stress distribution of knee joint after femoral fracture malunion and the relationship between stress value and residual varus varus or valgus deformity were analyzed.Results: Under 400 N vertical load, the stress values on the medial and lateral plateau of the tibia at the neutral position were 1.162±0.114 MPa and 1.103±0.144 MPa, respectively. When compared with the stress values measured at the neutral position, the stress on the medial plateau of tibia were significantly higher at varus deformities and lower at valgus deformities, and the stress on the lateral plateau was significantly higher at valgus deformity and lower at varus deformities (all P<0.05). The stress values on the medial plateau of tibia were significantly higher than the corresponding data on the lateral plateau at neutral and 3 degrees, 7 degrees, 10 degrees varus deformities, respectively (all P<0.05), and significantly lower than the corresponding data on the lateral plateau at 3 degrees, 7 degrees, 10 degrees valgus deformities, respectively (all P<0.05). Conclusions: Residual varus and valgus deformity after femoral fracture malunion can cause obvious changes of the stress distribution of knee joint. Therefore, the distal femoral fracture should be anatomically reduced and rigidly fixed to avoid residual varus-valgus deformity and malalignment of lower limbs.

Low-Degree Tibial Slope Angle Prevents Component Overhang by Enlarging the Lateral Plateau Surface Area in Total Knee Arthroplasty

This study aimed to investigate whether overhang or underhang around the tibial component that occurs during the placement of tibial baseplates was affected by different slope angles of the tibial plateau and determine the changes in the lateral and medial plateau diameters while changing the slope angle in total knee arthroplasty. Three-dimensional tibia models were reconstructed using the computed tomography scans of 120 tibial dry bones. Tibial plateau slope cuts were performed with 9, 7, 5, 3, and 0 degrees of slope angles 2-mm below the subchondral bone in the deepest point of the medial plateau. Total, lateral, and medial tibial plateau areas and overhang/underhang rates were measured at each cut level. Digital implantations of the asymmetric and symmetric tibial baseplates were made on the tibial plateau with each slope angles. Following the implantations, the slope angle that prevents overhang or underhang at the bone border and the slope angle that has more surface area was identified. A significant increase was noted in the total tibial surface area, lateral plateau surface area, and lateral anteroposterior distance, whereas the slope cut angles were changed from 9 to 0 degrees in both gender groups. It was found that the amount of posteromedial underhang and posterolateral overhang increased in both the asymmetric and symmetric tibial baseplates when the slope angle was changed from 0 to 9 degrees. Although the mediolateral diameter did not change after the proximal tibia cuts at different slope angles, the surface area and anteroposterior diameter of the lateral plateau could change, leading to increased lateral plateau area. Although prosthesis designs are highly compatible with the tibial surface area, it should be noted that the component overhangs, especially beyond the posterolateral edge, it can be prevented by changing the slope cut angle in males and females.

A real 3D measurement technique for the tibial slope: differentiation between different articular surfaces and comparison to radiographic slope measurement

Background The tibial slope plays an important role in knee surgery. However, standard radiographic measurement techniques have a low reproducibility and do not allow differentiation between medial and lateral articular surfaces. Despite availability of three-dimensional imaging, so far, no real 3D measurement technique was introduced and compared to radiographic measurement, which were the purposes of this study. Methods Computed tomography scans of 54 knees in 51 patients (41 males and 10 females) with a mean age of 46 years (range 22–67 years) were included. A novel 3D measurement technique was applied by two readers to measure the tibial slope of medial and lateral tibial plateau and rim. A statistical analysis was conducted to determine the intraclass correlation coefficient (ICC) for the new technique and compare it to a standard radiographic measurement. Results The mean 3D tibial slope for the medial plateau and rim was 7.4° and 7.6°, for the lateral plateau and rim 7.5° and 8.1°, respectively. The mean radiographic slope was 6.0°. Statistical analysis showed an ICC between both readers of 0.909, 0.987, 0.918, 0.893, for the 3D measurement of medial plateau, medial rim, lateral plateau and lateral rim, respectively, whereas the radiographic technique showed an ICC of 0.733. Conclusions The proposed novel measurement technique shows a high intraclass agreement and offers an applicable opportunity to assess the tibial slope three-dimensionally. Furthermore, the medial and lateral articular surfaces can be measured separately and one can differentiate the slope from the plateau and from the rim. As three-dimensional planning becomes successively more important, our measurement technique might deliver a useful supplement to the standard radiographic assessment in slope related knee surgery. Level of evidence Level III, diagnostic study.

The concept of direct approach to lateral tibial plateau fractures and stepwise extension as needed

Malreduction after tibial plateau fractures mainly occurs due to insufficient visualization of the articular surface. In 85% of all C-type fractures an involvement of the posterolateral-central segment is observed, which is the main region of malreduction. The choice of the approach is determined (1) by the articular area which needs to be visualized and (2) the positioning of the fixation material. For simple lateral plateau fractures without involvement of the posterolateral-central segment an anterolateral standard approach in supine position with a lateral plating is the treatment of choice in most cases. For complex fractures the surgeon has to consider, that the articular surface of the lateral plateau only can be completely visualized by extended approaches in supine, lateral and prone position. Anterolateral and lateral plating can also be performed in supine, lateral and prone position. A direct fixation of the posterolateral-central segment by a plate or a screw from posterior can be only achieved in prone or lateral position, not supine. The posterolateral approach includes the use of two windows for direct visualization of the fracture. If visualization is insufficient the approach can be extended by lateral epicondylar osteotomy which allows exposure of at least 83% of the lateral articular surface. Additional central subluxation of the lateral meniscus allows to expose almost 100% of the articular surface. The concept of stepwise extension of the approach is helpful and should be individually performed as needed to achieve anatomic reduction and stable fixation of tibial plateau fractures.