Morphologic Variants of Posterolateral Tibial Plateau Impaction Fractures in the Setting of Primary Anterior Cruciate Ligament Tear

The angle of the lower portion of the posterior cruciate ligament assists in the diagnosis of partial anterior cruciate ligament tears

PURPOSE

To compare the difference of angle of the lower portion of the posterior cruciate ligament (PCL) measured via magnetic resonance imaging (MRI) in patients with and without partial anterior cruciate ligament (ACL) tears and to investigate the effectiveness of the angle of the lower portion of the PCL in diagnosing partial ACL tears.

METHODS

From January 2022 to December 2022, a cohort of consecutive patients presenting with ACL tears who underwent ACL reconstruction and patients with isolated meniscus tears undergoing arthroscopic surgery were enroled for this study. The angle of the inferior portion of the PCL comprises α and β angles, and the posterior offset of the lateral condyle were measured on the MRI and compared between the partial ACL tear and control groups. Receiver operating characteristic curves, the areas under the curve (AUCs) and the 95% confidence intervals (CIs) were calculated to identify cutoff values for diagnosing partial ACL injuries.

RESULTS

Following an assessment of cohort eligibility and matching for age and sex, 100 patients were included in this study. The mean age of the cohort was 46.1 ± 10.3 years. The AUC for the α angle was 0.88 (95% CI, 0.82-0.94), with a sensitivity of 0.74 and specificity of 0.84 for predicting partial ACL ruptures; the α angle cutoff value was 73.6° (diagnostic odds ratio (OR), 14.10; 95% CI, 5.33-37.28). The AUC for the β angle was 0.86 (95% CI, 0.79-0.93), with a sensitivity of 0.64 and a specificity of 0.92 for predicting partial ACL ruptures; the β angle cutoff value was 73.3° (diagnostic OR, 14.54; 95% CI, 5.76-36.68).

CONCLUSIONS

A small α angle and a large β angle were associated with partial ACL tears. The angle of the distal portion of the PCL was simple to measure and reproducible, enhancing the diagnosis of partial ACL tears.

LEVEL OF EVIDENCE

Level III.

Intra- and interobserver reliability of two classification systems for posterolateral tibial plateau fractures in the setting of an ACL rupture

Background

Posterolateral tibial plateau impaction fractures occur frequently associated with anterior cruciate ligament (ACL) tears. Some authors advocate operative treatment of high-grade impaction fractures, which has led to the development of classification systems. Our study aims (1) to describe and compare the intra- and interobserver reliability of the two most used classifications and (2) to assess correlations between the grade of bony posterolateral tibial injury, patient characteristics and short-to mid-term revision rate after ACL reconstruction.

Materials and methods

In a retrospective series of 163 patients who underwent ACL reconstruction, two reviewers independently evaluated the preoperative MRI scans. Conform the Menzdorf and Bernholt classification the presence and grade of an associated posterolateral impaction fracture were assessed. Statistical analyses were performed to test for both study hypotheses.

Results

171 primary ACL cases were evaluated. Mean follow-up time was 41 months (range 12-154, SD = 17.1). Mean age was 32 years (range 13-59, SD = 12). Posterolateral impaction fractures were present in 111 (64.9 %) and 120 (70.0 %) cases, according to the Menzdorf and Bernholt classification. A Segond fracture was present in 19 (11.1 %) cases. Kappa value was 0.47 for intra- and 0.52 for the interobserver reliability for the Menzdorf classification (moderate reliability). For the Bernholt classification kappa values were 0.66 and 0.61, respectively (good reliability). A Segond fracture correlated significantly with the presence of a posterolateral impaction fracture (p < 0.05). A significant association was present between patients necessitating ACL revision surgery and patients for whom operative intervention for the posterolateral impression was advised following the Menzdorf classification (p < 0.001).

Conclusion

Inter- and intraobserver reliability testing for classifying posterolateral tibial fractures resulted in moderate to good reliability. High-grade posterolateral tibial fractures should be identified, selective treatment should be considered as they are associated with higher revision rates after ACL reconstruction if left untreated.

Incidence and Characteristics of Knee Ligament and Meniscal Injuries in Patients With Posterolateral Tibial Plateau Fractures

Background

Anterior cruciate ligament (ACL) tears are commonly seen with concomitant injuries to the posterolateral tibial plateau, while the occurrence of ACL injuries in posterolateral tibial plateau fractures (PTPFs) remains unclear.

Purpose

To (1) explore the incidence of knee ligament (anterior or posterior cruciate ligament, medial or lateral collateral ligament) and medial or lateral meniscus injuries in patients with PTPF and (2) find reliable PTPF-related parameters to predict the risk of knee ligament and meniscal injuries.

Study Design

Cross-sectional study; Level of evidence, 3.

Methods

Patients diagnosed with PTPF who had computed tomography and magnetic resonance imaging (MRI) data were identified. Morphological parameters of the PTPF were measured on sagittal computed tomography images. Knee ligament and meniscal injuries were assessed using MRI. The association of ACL injuries with meniscal injuries was analyzed. Receiver operating characteristic (ROC) analysis was used to determine the value and cutoff point of the PTPF morphological parameters for diagnosing complete in-substance ACL tears.

Results

Overall, 113 patients with PTPF were included. ACL injuries were present in 94 (83.2%) patients, including 43 (38.1%) avulsion fractures and 28 (24.8%) complete in-substance tears. Patients with in-substance ACL tears had a higher incidence of lateral meniscus posterior horn tears compared with the other patients (PBonferroni < .001). ROC analysis revealed that both the fracture depression angle (cutoff point, 25.5°) and the posterior articular surface loss percentage (cutoff point, 37.5%) had a sensitivity >90% and a specificity >80% for the diagnosis of complete in-substance ACL tears.

Conclusion

ACL injuries were seen in 83.2% of the study patients. Complete in-substance ACL tears were associated with an increased incidence of lateral meniscus posterior horn tears. Among PTPF parameters, fracture depression angle and posterior articular surface loss percentage showed a high predictive value for the presence of complete in-substance ACL tears, thereby reducing delays in diagnosis and treatment.

Utilization of cannulated screw fixation of Jail and TiRobot-assisted percutaneous indirect reduction technique for AO/OTA type 41B2 tibial plateau fracture treatment

PURPOSE

The present study was designed to investigate the precise procedure and effectiveness of percutaneous minimally invasive fixation assisted by TiRobot in managing AO/OTA type 41B2 tibial plateau fracture to provide an alternative solution for clinical application.

METHODS

In total, 10 participants with AO/OTA type 41B2 tibial plateau fractures diagnosed by preoperative imaging examinations were enrolled in this study between May 2019 and May 2022. They were 5 males and 5 females, with an average age of 45.6 ± 11.3 years old (range 27-62 years old). All of them had closed fractures, including 6 cases with anterior cruciate ligament (ACL) tibial insertion avulsion fractures, 1 case with medial collateral ligament (MCL) tear, and 4 cases with a lateral meniscus tear. From injury through surgery, the entire time frame was 4.0 ± 1.5 days (range, 2-7 days). Following indirect percutaneous reduction assisted by TiRobot, the Jail method was used to treat all patients with minimally invasive internal fixation. Patients with ligament or meniscus injurieswere treated with arthroscopic surgery in one stage. The standardized functional exercise was performed postoperatively. The knee function was measured using the Hospital for Special Surgery (HSS) score, and the fracture reduction was assessed through the Rasmussen radiology score.

RESULTS

All patients were followed up for 12.7 ± 6.8 months (6-24 months).The fracture healing time was 11.8 ± 0.8 weeks (10-13 weeks), and the X-rays revealed satisfactory fracture reduction.The knee joint's Rasmussen score was 17.8 ± 0.4 (in the range of 17-18) a year after the procedure, with 8 patients receiving outstanding ratings and 2 cases receiving satisfactory scores. The HSS score was 93.8 ± 2.3 (range, 89 to 96), of which 10 cases were excellent. The motion range of the kneewas 138.7°±2.7° (range, -5° to 0° to 135°). No adverse effects or serious complications, such as internal fixation failure, postoperative infection, popliteal vascular injury, and common peroneal nerve injury, were observed during the last follow-up visit.

CONCLUSIONS

The intelligent assistance and accurate guidance of TiRobot can simplify and standardize procedures of percutaneous minimally invasive fixation in theSchatzker type Ⅲ tibial plateau fracture treatment. This technique increases the precision of indirect percutaneous reduction and screw fixation while minimizing bone grafting.

Effectiveness of bone grafting versus cannulated screw fixation in the treatment of posterolateral tibial plateau compression fractures with concomitant ACL injury: a comparative study

BACKGROUND

Posterolateral tibial plateau compression fractures (PTPCF) are one of the significant factors leading to knee instability and anterior cruciate ligament (ACL) reconstruction failure. The effectiveness of fixation for such cases without the use of metal implants remains inconclusive. The aim of this study is to investigate whether the fixation with isolated bone grafting is stable enough for the treatment of PTPCF with concomitant ACL injuries.

METHODS

This retrospective study analyzed patients treated for concomitant ACL injuries and PTPCF in authors' institution. A total of 53 patients (21 males and 32 females) with an average age of 47.43 ± 14.71 years were included. Patient data were collected, including factors leading to injury, affected side, height, weight, and basic medical history. The posterior inclination angle and the lateral tibial plateau lateral inclination angle were measured to evaluate the fixation stability. Rasmussen functional score and HSS score were used to assess the knee functional recovery.

RESULTS

The bone grafting group achieved satisfactory levels of Rasmussen score (28.22 ± 0.85) and HSS knee joint function scores (95.57 ± 1.97). The cannulated screw fixation group had a Rasmussen knee joint function score of 28.70 ± 0.92 and a HSS knee joint function score of 96.07 ± 1.93. No statistically significant difference was found (P > 0.05). The cannulated screw fixation group had a mean posterior inclination angle reduction loss of 0.20° ± 1.11°, while the bone grafting group had a reduction loss of 0.18° ± 1.01°, with no statistically significant difference (P > 0.05). The cannulated screw fixation group had a lateral inclination angle reduction loss of 0.01° ± 0.37°, and the bone grafting group had a reduction loss of 0.03° ± 0.43°, with no statistically significant difference (P > 0.05).

CONCLUSION

The use of bone grafting for fixation of PTPCF with accompanying ACL injuries demonstrated no substantial disparities in knee joint function. In cases of simple PTPCF, filling and compacting the bone defect underneath the tibial plateau fracture fragment can yield satisfactory fixation, obviating the necessity for supplementary cannulate screw fixation.

3D-validation of a simple tool to measure tibiofemoral axial rotation in tibial plateau fractures

OBJECTIVES

Rotated tibial plateau fractures (TPF) frequently involve multiple planes of movement, yet current presurgical assessment methods do not account for tibiofemoral axial rotation. This study introduces and validates a simple tool to measure rotation-the Gerdy-Tibial-Tuberosity-Surgical-Epicondylar-Axis (GTT-SEA) angle.

METHODS

Forty-seven preoperative 2D CT from a TPF database at a tertiary trauma center were retrieved, and 3D models reconstructed. Three observers made repeated 2D and 3D measurements of the GTT-SEA angle, spaced 4 weeks apart, for 20 patients. Inter- and intra-observer agreement and 2D-3D correlation were calculated. A reference angle was defined from non-operated patients, to classify 28 patients with MRI into neutral, external rotation, and internal rotation groups. The classification agreement and soft tissue involvement between groups were analyzed.

RESULTS

Mean 2D GTT-SEA angle was 17.65 ± 2.36° in non-operated patients, and 13.86 ± 3.90° in operated patients. 3D GTT-SEA angle was 18.92 ± 4.53° in non-operated patients, and 14.76 ± 6.03° in operated patients. 2D-3D correlation was moderate to good (ICC 0.64 ~ 0.83). Two-dimensional (ICC 0.70) and 3D (ICC 0.55) inter-observer agreements were moderate; 2D (ICC 0.82 ~ 0.88) and 3D (ICC 0.76 ~ 0.95) intra-observer agreements were good to excellent. Rotation classification agreement was slight (kappa 0.17) for 2D and good (kappa 0.76) for 3D. More popliteofibular ligament injury was detected in rotated knees (p = 0.016).

CONCLUSIONS

The GTT-SEA angle offers simple, accessible, yet reliable measurement of tibiofemoral axial rotation. Though a true reference range remains to be determined, this tool adds valuable information to existing TPF classifications, potentially allowing assessment of soft tissue involvement in TPF.

CLINICAL RELEVANCE STATEMENT

The GTT-SEA angle will benefit patients who sustain tibial plateau fractures, by allowing physicians to more accurately measure and plan for the injury in 3D, and raising suspicion for otherwise undetected soft tissue injuries, which can impact operative outcomes.

KEY POINTS

• Traumatic fractures of the tibial plateau may contain rotation-induced soft tissue injuries. • A new tool to measure axial rotation between the femur and tibia was found to have moderate to excellent inter- and intra-rater reliability. • The tool may have potential in predicting soft tissue injury and assisting with the decision to receive MRI.

The "Bankart knee": high-grade impression fractures of the posterolateral tibial plateau lead to increased translational and anterolateral rotational instability of the ACL-deficient knee

PURPOSE

The aim of this biomechanical cadaver study was to evaluate the effects of high-grade posterolateral tibia plateau fractures on the kinematics of anterior cruciate ligament (ACL)-deficient joints; it was hypothesized that, owing to the loss of the integrity of the osseous support of the posterior horn of the lateral meniscus (PHLM), these fractures would influence the biomechanical function of the lateral meniscus (LM) and consequently lead to an increase in anterior translational and anterolateral rotational (ALR) instability.

METHODS

Eight fresh-frozen cadaveric knees were tested using a six-degree-of-freedom robotic setup (KR 125, KUKA Robotics, Germany) with an attached optical tracking system (Optotrack Certus Motion Capture, Northern Digital, Canada). After the passive path from 0 to 90° was established, a simulated Lachman test and pivot-shift test as well as external rotation (ER) and internal rotation (IR) were applied at 0°, 30°, 60° and 90° of flexion under constant 200 N axial loading. All of the parameters were initially tested in the intact and ACL-deficient states, followed by two different types of posterolateral impression fractures. The dislocation height was 10 mm, and the width was 15 mm in both groups. The intraarticular depth of the fracture corresponded to half of the width of the posterior horn of the lateral meniscus in the first group (Bankart 1) and 100% of the meniscus width in the second group (Bankart 2).

RESULTS

There was a significant decrease in knee stability after both types of posterolateral tibial plateau fractures in the ACL-deficient specimens, with increased anterior translation in the simulated Lachman test at 0° and 30° of knee flexion (p = 0.012). The same effect was seen with regard to the simulated pivot-shift test and IR of the tibia (p = 0.0002). In the ER and posterior drawer tests, ACL deficiency and concomitant fractures did not influence knee kinematics (n.s.).

CONCLUSION

This study demonstrates that high-grade impression fractures of the posterolateral aspect of the tibial plateau increase the instability of ACL-deficient knees and result in an increase in translational and anterolateral rotational instability.

Association of medial collateral ligament complex injuries with anterior cruciate ligament ruptures based on posterolateral tibial plateau injuries

BACKGROUND

The combined injury of the medial collateral ligament complex and the anterior cruciate ligament (ACL) is the most common two ligament injury of the knee. Additional injuries to the medial capsuloligamentous structures are associated with rotational instability and a high failure rate of ACL reconstruction. The study aimed to analyze the specific pattern of medial injuries and their associated risk factors, with the goal of enabling early diagnosis and initiating appropriate therapeutic interventions, if necessary.

RESULTS

Between January 2017 and December 2018, 151 patients with acute ACL ruptures with a mean age of 32 ± 12 years were included in this study. The MRIs performed during the acute phase were analyzed by four independent investigators-two radiologists and two orthopedic surgeons. The trauma impact on the posterolateral tibial plateau and associated injuries to the medial complex (POL, dMCL, and sMCL) were examined and revealed an injury to the medial collateral ligament complex in 34.4% of the patients. The dMCL was the most frequently injured structure (92.2%). A dMCL injury was significantly associated with an increase in trauma severity at the posterolateral tibial plateau (p < 0.02) and additional injuries to the sMCL (OR 4.702, 95% CL 1.3-133.3, p = 0.03) and POL (OR 20.818, 95% CL 5.9-84.4, p < 0.0001). Isolated injuries to the sMCL were not observed. Significant risk factors for acquiring an sMCL injury were age (p < 0.01) and injury to the lateral meniscus (p < 0.01).

CONCLUSION

In about one-third of acute ACL ruptures the medial collateral ligament complex is also injured. This might be associated with an increased knee laxity as well as anteromedial rotational instability. Also, this might be associated with an increased risk for failure of revision ACL reconstruction. In addition, we show risk factors and predictors that point to an injury of medial structures and facilitate their diagnosis. This should help physicians and surgeons to precisely diagnose and to assess its scope in order to initiate proper therapies. With this in mind, we would like to draw attention to a frequently occurring combination injury, the so-called "unlucky triad" (ACL, MCL, and lateral meniscus). Level of evidence Level III Retrospective cohort study.

Establishing a Consensus Definition of a Knee Fracture-Dislocation (Schenck Knee Dislocation V) Using a Global Modified Delphi Method

BACKGROUND

Knee fracture-dislocations are complex injuries; however, there is no universally accepted definition of what constitutes a fracture-dislocation within the Schenck Knee Dislocation (KD) V subcategory. The purpose of this study was to establish a more precise definition for fracture patterns included within the Schenck KD V subcategory.

METHODS

A series of clinical scenarios encompassing various fracture patterns in association with a bicruciate knee ligament injury was created by a working group of 8 surgeons. Utilizing a modified Delphi technique, 46 surgeons from 18 countries and 6 continents with clinical and academic expertise in multiligamentous knee injuries undertook 3 rounds of online surveys to establish consensus. Consensus was defined as ≥70% agreement with responses of either "strongly agree" or "agree" for a positive consensus or "strongly disagree" or "disagree" for a negative consensus.

RESULTS

There was a 100% response rate for Rounds 1 and 2 and a 96% response rate for Round 3. A total of 11 fracture patterns reached consensus for inclusion: (1) nondisplaced articular fracture of the femur; (2) displaced articular fracture of the femur; (3) tibial plateau fracture involving the weight-bearing surface (with or without tibial spine involvement); (4) tibial plateau peripheral rim compression fracture; (5) posterolateral tibial plateau compression fracture, Bernholt type IIB; (6) posterolateral tibial plateau compression fracture, Bernholt type IIIA; (7) posterolateral tibial plateau compression fracture, Bernholt type IIIB; (8) Gerdy's tubercle avulsion fracture with weight-bearing surface involvement; (9) displaced tibial tubercle fracture; (10) displaced patellar body fracture; and (11) displaced patellar inferior pole fracture. Fourteen fracture patterns reached consensus for exclusion from the definition. Two fracture patterns failed to reach consensus for either inclusion or exclusion from the definition.

CONCLUSIONS

Using a modified Delphi technique, this study established consensus for specific fracture patterns to include within or exclude from the Schenck KD V subcategory.

LEVEL OF EVIDENCE

Prognostic Level V . See Instructions for Authors for a complete description of levels of evidence.

Anterolateral approach for posterolateral tibial plateau fractures

The posterolateral tibial plateau fracture is an uncommon intra-articular injury and mostly needed surgery. However, its surgical approach remains controversial. This manuscript describes an anterolateral approach to treat posterolateral tibial plateau fractures and evaluates the patient's functional outcomes. From June 2018 to July 2021 seventeen patients with posterolateral tibial plateau fractures were surgically treated through an anterolateral approach. The intraoperative and postoperative follow-up indicators were recorded. The reduction quality of fractures was assessed using Rasmussen radiological score, and postsurgical functional recovery was estimated using Rasmussen clinical score and Lysholm score. The mean follow-up interval was 28.71 ± 9.61 months (range 18-44). The surgery time and blood loss were 111.06 ± 15.62 min (range 85-140) and 118.12 ± 38.45 mL (range 80-250) separately. Postoperatively, the Rasmussen radiological score was 16.24 ± 2.33 (range 12-18). The average time of bone union was 14.29 ± 1.53 weeks (range 12-18). At the final follow-up, the average PTS and MPTA were 9.71 ± 2.76° (range 5-14°) and 86.82 ± 2.04° (range 84-90°) separately. A satisfactory articular reduction was achieved in 16 patients (94.1%). The final ROM was 123.29 ± 19.70° (range 60-142°). The Rasmussen clinical score and Lysholm score were 25.71 ± 5.74 (range 10-30) and 91.47 ± 6.50 (range 75-98) separately. Anterolateral approach has minimal risk of intraoperative neurovascular injuries in the popliteal fossa with satisfactory results. The hardware removal was also facilitated. This approach is feasible, safe and efficient.

Clinical Outcomes of Fixation of Depressed Posterolateral Tibial Plateau Fractures Using a Direct Lateral Approach

Introduction

Fixation of plateau posterolateral fracture (PLF) is challenging because the fracture site is mostly covered by vital neurovascular structures. We operated on 15 cases of PLF using a direct lateral approach. This study aims to report on clinical results.

Material and methods

Between 2017 and 2019, 15 cases of PLFs were fixed with a direct lateral approach and a tricortical autologous bone graft from the iliac crest. A depression of more than 2 mm was indicated for the surgical treatment. Clinical evaluation included Lysholm score, International Knee Documentation Committee Score (IKDC) score, and Tegner activity scale after two years follow-up.

Results

The last follow-up was at 24 months after the operation. The mean postoperative Tegner activity scale did not change significantly compared to before the injury (6.5 (6-7) vs. 7 (6-8, p = 0.5)). The postoperative IKDC and Lysholm scores improved significantly compared to before the operation (p < 0.001). The full range of motion was seen in all patients except one who was manipulated after three months.

Conclusions

Surgical treatment using a direct lateral approach is a safe procedure for PLFs that results in good, short-term clinical and radiologic outcomes without fibular osteotomy or compromising the important neurovascular structures.

Level of evidence

IV.

Posterior tibial plateau impaction fractures are not associated with increased knee instability: a quantitative pivot shift analysis

PURPOSE

This study aimed to evaluate posterolateral tibial plateau impaction fractures and how they contribute to rotatory knee laxity using quantitative pivot shift analysis. It was hypothesised that neither the presence of nor the degree of involvement of the plateau would affect rotatory knee laxity in the ACL-deficient knee.

METHODS

A retrospective review of prospectively collected data on 284 patients with complete anterior cruciate ligament (ACL) injuries was conducted. Posterolateral tibial plateau impaction fractures were identified on preoperative MRI. The patients were divided into two cohorts: "fractures" or "no fractures". The cohort with fractures was further categorised based on fracture morphology: "extra-articular", "articular-impaction", or "displaced-articular fragment". All data were collected during examination under anaesthesia performed immediately prior to ACL reconstruction. This included a standard pivot shift test graded by the examiner and quantitative data including anterior tibial translation (mm) via Rolimeter, quantitative pivot shift (QPS) examination (mm) via PIVOT tablet technology, and acceleration (m/sec²) during the pivot shift test via accelerometer. Quantitative examinations were compared with the contralateral knee.

RESULTS

There were 112 patients with posterolateral tibial plateau impaction fractures (112/284, 39%). Of these, 71/112 (63%) were "extra-articular", 28/112 (25%) "articular-impaction", and 13/112 (12%) "displaced-articular". Regarding the two groups with or without fractures, there was no difference in subjective pivot shift (2 ± 0 vs 2 ± 0, respectively,  n.s.), QPS (2.4 ± 1.6 mm vs 2.7 ± 2.2 mm, respectively, n.s.), anterior tibial translation measurements (6 ± 3 mm vs 5 ± 3 mm, respectively, n.s.), or acceleration of the knee during the pivot (1.7 ± 2.3 m/s² vs 1.8 ± 3.1 m/s², respectively, n.s.). When the fractures were further subdivided, subgroup analysis revealed no significant differences noted in any of the measured examinations between the fracture subtypes.

CONCLUSION

This study showed that the posterolateral tibial plateau impaction fractures are commonly encountered in the setting of ACL tears; however, contrary to previous reports, they do not significantly increase rotatory knee laxity. This suggests that this type of concomitant injury may not need to be addressed at the time of ACL reconstruction.

LEVEL OF EVIDENCE

Level III.

The Incidence of Posterolateral Tibial Plateau and Central Lateral Femoral Condylar Impaction Fractures in a Pediatric and Young Adult Population

BACKGROUND

Posterolateral tibial plateau and central lateral femoral condylar impaction fractures are known to occur in the setting of anterior cruciate ligament (ACL) tears. There have been no prior investigations into the incidence and morphology of posterolateral tibial plateau impaction fractures in the setting of ACL injury in a pediatric population.

METHODS

Patients between 9 and 22 years of age with knee magnetic resonance imagings (MRIs) performed demonstrating complete or partial ACL tear were included in this study. MRI reports were reviewed to denote the presence of posterior cruciate ligament, medial collateral ligament, or lateral collateral ligament injury, meniscus tears, cartilage lesions. MRIs were reviewed by 2 fellowship-trained orthopaedic surgeons to denote the presence of posterolateral tibial plateau and central lateral femoral condylar impaction fractures and physeal status of femoral and tibial physes. Statistical analysis performed included χ 2 analysis and the Student t testing.

RESULTS

A total of 328 patients with a primary ACL tear were identified. The mean age of patients included was 16.5 years (range: 9.0-21.5). The incidence of posterolateral tibial plateau impaction fractures was 83/328 (25.3%) while the incidence of lateral femoral condylar impaction fractures was 119/328 (36.3%). Bipolar impaction fractures occurred in 37/328 (11.3%). Of the 83 tibial impaction fractures identified, 82 were low-grade morphologic subtypes. Patients with lateral tibial plateau impaction fractures were older than those with no fracture (17.2±2.2 vs. 16.3±2.1, P =0.001). Only 3/38 (7.9%) patients with an open tibial physis sustained a tibial plateau impaction fracture compared with 80/290 (27.6%) with a closed tibial physis (χ 2 value: 6.9, P =0.009). There was no difference in proportion of patients with lateral femoral condylar impaction fractures based on femoral physeal status ( P =0.484).

CONCLUSION

The incidence of posterolateral tibial plateau impaction fractures in the setting of ACL tear in a pediatric and young adult patient population appears to be lower while lateral femoral condylar impaction fractures occur more frequently when comparing to previously reported incidences found in adult populations in the literature. Furthermore, posterolateral tibial plateau impaction fractures occur less frequently in those with an open proximal tibial physis and high-grade posterolateral tibial plateau bone loss is exceedingly rare in pediatric and young adult patients. Lateral femoral condylar impaction fractures are associated with lateral meniscal tears and medial meniscal ramp lesions.

LEVEL OF EVIDENCE

Level IV-cross-sectional study.

Extent of posterolateral tibial plateau impaction fracture correlates with anterolateral complex injury and has an impact on functional outcome after ACL reconstruction

PURPOSE

The impact of posterolateral tibial plateau impaction fractures (TPIF) on posttraumatic knee stability in the setting of primary anterior cruciate ligament (ACL) tear is unknown. The main objective was to determine whether increased bone loss of the posterolateral tibial plateau is associated with residual rotational instability and impaired functional outcome after ACL reconstruction.

METHODS

A cohort was identified in a prospective enrolled study of patients suffering acute ACL injury who underwent preoperative standard radiographic diagnostics and clinical evaluation. Patients were included when scheduled for isolated single-bundle hamstring autograft ACL reconstruction. Exclusion criteria were concurrent anterolateral complex (ALC) reconstruction (anterolateral tenodesis), previous surgery or symptoms in the affected knee, partial ACL tear, multi-ligament injury with an indication for additional surgical intervention, and extensive cartilage wear. On MRI, bony (TPIF, tibial plateau, and femoral condyle morphology) and ligament status (ALC, concomitant collateral ligament, and meniscus injuries) were assessed by a musculoskeletal radiologist. Clinical evaluation consisted of KT-1000, pivot-shift, and Lachman testing, as well as Tegner activity and IKDC scores.

RESULTS

Fifty-eight patients were included with a minimum follow-up of 12 months. TPIF was identified in 85% of ACL injuries (n = 49). The ALC was found to be injured in 31 of 58 (53.4%) cases. Pearson analysis showed a positive correlation between TPIF and the degree of concomitant ALC injury (p < 0.001). Multiple regression analysis revealed an increased association of high-grade TPIF with increased lateral tibial convexity (p = 0.010). The high-grade TPIF group showed worse postoperative Tegner scores 12 months postoperatively (p = 0.035).

CONCLUSION

Higher degrees of TPIFs are suggestive of a combined ACL/ALC injury. Moreover, patients with increased posterolateral tibial plateau bone loss showed lower Tegner activity scores 12 months after ACL reconstruction.

LEVEL OF EVIDENCE

III.

The pivot fracture: an unusual tibial plateau fracture found in association with acute ACL injury

Tibial plateau fractures are common fractures which are often associated with concurrent soft tissue injury and for which accurate preoperative diagnosis is important for development of an appropriate treatment plan and outcome prediction. Here, we present an extreme manifestation of the pivot shift phenomenon with an unusual tibial plateau fracture with flipped component not described by any existing tibial plateau fracture classification system and never reported previously in conjunction with an anterior cruciate ligament injury. We describe the utilization of advanced imaging not typically utilized in the management of tibial plateau fractures in combination with clinical suspicion to diagnose the associated soft tissue injuries and develop an appropriate management plan.

Surgical exposure to posterolateral quadrant tibial plateau fractures: an anatomic comparison of posterolateral and posteromedial approaches

BACKGROUND

Management of posterolateral tibial plateau quadrant fractures can be challenging, and two posterior approaches were frequently used for exposure, reduction, and fixation: posterolateral approach and posteromedial approach. The purpose of this study was to compare their deep anatomical structure and analyze their limits and the risk of injury to important structures during surgical dissection of two approaches.

METHOD

Five lower limb specimens were used in this study. After dissection of the skin and superficial fascia of each specimen, deep structures were dissected via posteromedial and posterolateral approach, and several parameters including perpendicular distance from the anterior tibial artery coursing through the interosseous membrane fissure to the lateral joint line and apex of fibular head and so on were measured and analyzed.

RESULT

The perpendicular distance from the ATA coursing through the interosseous membrane fissure to the lateral joint line was 49.3 ± 5.6 mm (range 41.3-56.7 mm), while the distance to the apex of fibular head was 37.7 ± 7.2 mm (range 29.0-48.0 mm). The transverse distance of the anterior tibial vascular bundle is around 10 mm. The perpendicular distance from the top accompanying vein of the ATA bundle to lateral joint line and apex of fibular head was 44.1 ± 6.3 mm and 32.5 ± 7.6 mm, respectively. The maximum proportion of posterolateral tibial plateau shielded by the fibular head from the posterior view was 61.7 ± 4.9% (range 55.6-64.1%). The average length of popliteus muscle outside the joint was 83.1 ± 6.0 mm (range 76.5-92.2 mm), and the width in the middle was 28.1 ± 4.3 mm (range 26.6-29.1 mm).

CONCLUSION

Although posterolateral approach seems more direct for exposure of posterolateral quadrant tibial plateau fracture, it has three major disadvantages in deep dissection. Posteromedial approach through the medial board of medial head of gastrocnemius-soleus may be safer, but it was hard for direct visualization of articular surface which limits it usage for only a few cases.

Posterolateral Fractures of the Tibial Plateau Revisited: A Simplified Treatment Algorithm

High-energy fractures of the proximal tibia with extensive fragmentation of the posterolateral (PL) quadrant of the tibial plateau are challenging to manage. Herein, we present a review of the literature on the patterns and options of approach and fixation of the PL fragment of the tibial plateau to optimize the treatment of this specific injury pattern. We searched PubMed (1980-May 2020) to identify and summarize the most relevant articles evaluating both the morphology and treatment recommendations, including the choice of approach and fixation strategy, for the PL tibial plateau fracture. We found PL fragment can present in several patterns as a pure split, split depression, contained pure depression, and noncontained depression (rim crush), which are mostly determined by the position of the knee and the force magnitude applied during the course of the accident. Based on previous concepts described by Schatzker and Kfuri, we suggest a simplified treatment algorithm highlighting the two concepts (buttressing and containment) used for plating the PL tibial plateau fragments. Based on the available current evidence, we propose an algorithm for these two morphological types of PL tibial plateau fracture. Shear-type fractures need buttressing (the "rule of thumb"), whereas noncontained peripheral rim-type fractures need peripheral repair and containment. Contained pure depression fractures are not frequent and need percutaneous-assisted elevation and subchondral rafting, either controlled by fluoroscopy or arthroscopically. It is believed that such an approach would simplify their assessment and preoperative planning and would assist the clinicians to appreciate and manage more consistently these complex injuries.

Revisiting the management of tibial plateau fractures

Three-dimensional imaging has changed the understanding and management of tibial plateau fractures. In the 1970s, Schatzker proposed a classification for tibial plateau fractures, which highlighted the morphology of the six principal types. More recently, this original classification was complimented by an extended one underscoring the importance of understanding where the split wedge fragment(s) is/are located in three dimensions. The extended classification introduced the split wedge fragment and the continuity of the rim as the determinants of joint stability and the critical role that this plays in the management of tibial plateau fractures. The current manuscript re-emphasizes contemporary concepts of tibial plateau stability and depicts key issues which must be considered when planning the definitive surgical fixation of tibial plateau fractures.

Optimal Tibial Tunnel Placement for Medial and Lateral Meniscus Root Repair on the Anteromedial Tibia in the Setting of Anterior and Posterior Cruciate Ligament Reconstruction of the Knee

BACKGROUND

Although the risk of tibial tunnel convergence in the setting of multiligamentous reconstruction has been reported in the literature, the risk of tunnel convergence in the setting of posterior cruciate ligament (PCL), anterior cruciate ligament (ACL) reconstruction and medial and lateral meniscus root repair has not been defined.

PURPOSE

To examine the risk of tunnel convergence and to determine optimal tunnel placement for ACL and PCL reconstruction performed in conjunction with posterior medial and lateral meniscus root repairs on the anteromedial proximal tibia.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Three-dimensional (3D) tibial models were created using computed tomography scans of 20 cadaveric specimens. After determining optimal tunnel entry and exit points for ACL and PCL reconstructions, and medial and lateral meniscus root reattachment to the anatomic footprints, we used image processing software to create root tunnels over the anteromedial tibia on the tibial models. ACL and PCL tunnels were kept constant. The meniscus root repair tunnels were then reoriented to match the angle of the ACL tunnel, making both tunnels parallel in the sagittal plane. Tunnel convergence risk was analyzed by identifying the shortest 3D distance between tunnel axes and subtracting the radius of each tunnel from this distance for single- and double-tunnel repair techniques in both case scenarios.

RESULTS

All specimens demonstrated convergence between the ACL and lateral meniscus root tunnels when the root tunnel's entry was created proximal to the ACL tunnel's entry for single- and double-tunnel techniques, but no convergence was seen between these tunnels using the parallel orientation in the sagittal plane. There were no cases of convergence between the ACL and medial meniscus root tunnels in any of the configurations. The greatest distance between the ACL and medial meniscus root tunnels was achieved using the single-tunnel technique in parallel orientation (12.1 ± 2.8 mm). There were no cases of convergence between the PCL and medial meniscus root tunnels in the original orientation; however, 2 of 20 specimens demonstrated convergence using the parallel orientation with the double-tunnel technique, and there were no cases of convergence using the single-tunnel technique. The PCL and lateral meniscus root tunnels did not demonstrate convergence in any configuration.

CONCLUSION

There was a high risk of convergence between ACL and posterior meniscus root tunnels when all the tunnels were created on the anteromedial tibia. Reorienting meniscus root tunnels parallel to ACL tunnels may help reduce this risk. There is increased risk of tunnel convergence with root repairs in cases of bicruciate reconstructions, and therefore a double-tunnel root repair technique should be used with caution.

CLINICAL RELEVANCE

To avoid tibial tunnel convergence when performing ACL and PCL reconstruction with medial and lateral meniscus root repair, surgeons should reorient the meniscus root repair tunnels to be parallel on the sagittal plane to the ACL tunnel to decrease the risk of convergence. In cases of bicruciate ligament reconstruction, use of the double-tunnel technique requires caution to avoid convergence risk with the PCL tunnel.

Intra- and inter-observer reliability assessment of widely used classifications and the "Ten-segment classification" of tibial plateau fractures

BACKGROUND

Ten-segment classification provides a different approach to the evaluation of tibial plateau fractures. The purpose of this study was to assess the intra- and inter-observer reliability of three widely used classification systems (Schatzker, Arbeitsgemeinschaft für Osteosynthesefragen (AO/OTA), and the updated three-column concept (uTCC)) with ten-segment classification in two-dimensional computed tomography (2D-CT) and three-dimensional computed tomography (3D-CT).

METHOD

Ninety 2D-CT and 3D-CT scans of patients with tibial plateau fractures were included in this retrospective cohort study. The included data were independently classified by six observers of different years of seniority and were independently observed and classified again after eight weeks. Inter-observer and intra-observer reliability of the four fracture classifications made by the six observers was analyzed using the kappa statistic. Kappa values were interpreted according to the categorical rating by Landis and Koch.

RESULTS

When the inter-observer reliability was based on 2D-CT/3D-CT analysis, the mean Kappa values for the Schatzker, AO/OTA, uTCC, and ten-segment classification were 0.64/0.66, 0.56/0.59, 0.53/0.65, and 0.60/0.73, respectively. When intra-observer reliability was based on 2D-CT/3D-CT, the mean Kappa values for the Schatzker, AO/OTA, uTCC, and ten-segment classification were 0.68/0.83, 0.69/0.83, 0.74/0.85, and 0.80/0.91, respectively.

CONCLUSIONS

The use of 3D-CT is important for the reliable diagnosis and recognition of tibial plateau fracture features compared to 2D-CT. When using 3D-CT, ten-segment classification showed high intra- and inter-observer agreement.

Lateral femoral notch sign and posterolateral tibial plateau fractures and their associated injuries in the setting of an anterior cruciate ligament rupture

INTRODUCTION

ACL injury is one of the most common injuries of the knee joint in sports. As accompanying osseous injuries of the ACL rupture a femoral impression the so-called lateral femoral notch sign and a posterolateral fracture of the tibial plateau are described. However, frequency, concomitant ligament injuries and when and how to treat these combined injuries are not clear. There is still a lack of understanding with which ligamentous concomitant injuries besides the anterior cruciate ligament injury these bony injuries are associated.

MATERIALS AND METHODS

One hundred fifteen MRI scans with proven anterior cruciate ligament rupture performed at our center were retrospectively evaluated for the presence of a meniscus, collateral ligament injury, a femoral impression, or a posterolateral impression fracture. Femoral impressions were described according to their local appearance and posterolateral tibial plateau fractures were described using the classification of Menzdorf et al. RESULTS: In 29 cases a significant impression in the lateral femoral condyle was detected. There was a significantly increased number of lateral meniscal (41.4% vs. 18.6% p = 0.023) and medial ligament (41.4% vs. 22.1%; p = 0.040) injuries in the group with a lateral femoral notch sign. 104 patients showed a posterolateral bone bruise or fracture of the tibial plateau. Seven of these required an intervention according to Menzdorf et al. In the group of anterior cruciate ligament injuries with posterolateral tibial plateau fracture significantly more lateral meniscus injuries were seen (p = 0.039).

CONCLUSION

In the preoperative planning of ACL rupture accompanied with a positive femoral notch sign, attention should be paid to possible medial collateral ligament and lateral meniscus injuries. As these are more likely to occur together. A posterolateral impression fracture of the tibial plateau is associated with an increased likelihood of the presence of a lateral meniscal injury. This must be considered in surgical therapy and planning and may be the indication for necessary early surgical treatment.

SIMULATION OF THE RELATIONSHIP BETWEEN EXERCISE AND CARDIOPULMONARY FUNCTION AT HIGH ALTITUDE

ABSTRACT Introduction: Due to various uncertain and unexpected factors in life such as diseases, natural disasters, traffic accidents, and congenital disabilities, the number and proportion of lower limb amputations are still rising for many reasons, so the research on lower limb prostheses is particularly important. Objective: This work aimed to study the relationship between altitude exercise and cardiopulmonary function. Methods: A model of abnormal changes in cardiopulmonary function was established, and then 40 plateau exercisers were selected, all of whom arrived in Tibet in March 2017. The relationship between pulmonary circulation volume and internal pressure in the chest was observed and compared. The relationship between cardiopulmonary sensory reflex and exercise (high altitude) breathing and heart rate was analyzed. A comparison of the cardiopulmonary function of subjects of different genders was implemented. Moreover, the influence of different altitudes on the subjects’ cardiopulmonary function and the subjects’ cardiopulmonary function changes before departure and during the first, second, and third week after departure were observed and compared. Results: I. As the pressure in the thoracic cavity increased, the subjects’ pulmonary circulation blood volume gradually decreased, and the decrease was most obvious in the stage of thoracic pressure −50 to 0. II. As the cardiorespiratory reflex coefficient increased, the subjects’ breathing and heart rate compensatory acceleration appeared. III. Tracking and monitoring of the subjects’ cardiopulmonary indicators revealed that with the increase in altitude, the subjects’ average arterial pressure, respiratory frequency, and heart rate all showed an upward trend, while the blood oxygen saturation value showed a downward trend. IV. No matter how high the altitude was, the average arterial pressure, respiratory rate, and heart rate monitored of the subjects under exercise were significantly superior to the indicator values under resting state. In contrast, the blood oxygen saturation value showed the opposite trend. V. The subjects’ average arterial pressure, respiration, and heart rate in the first week were higher than other periods, but the blood oxygen saturation was relatively lower. In the second and third weeks, the changes in cardiopulmonary function were relatively smooth (all P<0.05). VI. The changes in the index of the cardiopulmonary function of subjects of different genders were small (p>0.05). Conclusion: Through modeling, the results of the plateau environment on the cardiopulmonary function of the body were made clearer, and these research data provided theoretical references for the training of the sports field in the plateau area. Level of evidence II; Therapeutic studies - investigation of treatment results.

A posterolateral sheared fracture of the tibial plateau: a case presentation

Background

Among tibial plateau fractures, one specialized type is the posterolateral column fracture. There are few published studies on posterolateral tibial plateau fractures with a sheared fragment that was wedged into the intercondylar fossa without the anterior cruciate ligament (ACL) rupture. According to our research, this case presentation is the first to describe in detail the treatment and long-term follow-up for this uncommon subtype of posterolateral tibial plateau fracture.

Case presentation

A 46-year-old female injured her right knee when she was riding a motorbike and was diagnosed with a posterolateral sheared tibial plateau fracture with a wedge-shaped fragment inserted into the femoral intercondylar fossa. The fracture was repaired with open reduction internal fixation surgery. The patient’s recovery was followed for four years. The degree of healing as indicated by clinical and radiological examinations was substantial. The patient exhibited an excellent range of motion for the repaired knee (0-145°) and little discomfort. The Lysholm score was 96, the hospital for special surgery score was 98, the Rasmussen clinical assessment was 28, and the Rasmussen radiological assessment was 18.

Conclusion

This study revealed that a posterolateral sheared tibial plateau, as seen in this case, can be reset and fixed sufficiently to achieve excellent long-term postoperative recovery.

Clinical Anatomy of the Anterior Meniscofemoral Ligament of Humphrey: An Original MRI Study, Meta-analysis, and Systematic Review

Background:

The anterior meniscofemoral ligament (aMFL) of Humphrey is an anatomically variable fibrous band of connective tissue that attaches between the lateral aspect of the medial femoral condyle and posterior horn of the lateral meniscus, running posterior to the anterior cruciate ligament and anterior to the posterior cruciate ligament (PCL). The presence of an intact aMFL may contribute to stabilization of the lateral compartment of the knee joint.

Purpose:

The original magnetic resonance imaging (MRI) arm of this study aimed to assess the aMFL incidence among Polish patients. The goal of the systematic review and meta-analysis was to review the literature discussing the clinical anatomy of the aMFL and provide data on its prevalence. It was hypothesized that significant heterogeneity exists within the published literature.

Study Design:

Cross-sectional study and systematic review; Level of evidence, 3.

Methods:

A retrospective investigation was performed on the MRI scans of 100 knees (52 right, 48 left) of Polish patients. Scans were randomly selected from a database of MRI examinations performed in 2019. For the meta-analysis, major online databases were queried for data on the aMFL, and 2 authors independently assessed and extracted data from all included studies. A quality assessment of the included articles was performed using the Anatomical Quality Assessment tool.

Results:

In the MRI arm of this study, the aMFL was found in 62 of the 100 lower limbs. The meta-analysis included 41 studies with a total of 4220 limbs. The aMFL was present in 55.5% (95% CI, 45.5%-65.3%) of cases. Arthroscopic studies yielded the highest prevalence (82.3% [95% CI, 36.6%-100.0%]); of MRI studies, the highest prevalence was at 3.0-T strength (51.0% [95% CI, 13.3%-88.2%]).

Conclusion:

Significant variability in the prevalence of the aMFL was found in the literature. More emphasis should be placed on the clinical relevance of injuries to the aMFL because of its significant role in the function of the knee. It is important to be aware that, because of the anatomy of the aMFL, the ligament can also function to support a torn PCL.

Clinical Anatomy of the Posterior Meniscofemoral Ligament of Wrisberg: An Original MRI Study, Meta-analysis, and Systematic Review

Background

The posterior meniscofemoral ligament (pMFL) of Wrisberg attaches to the posterior horn of the lateral meniscus and the lateral intercondylar aspect of the medial femoral condyle and passes posteriorly to the posterior cruciate ligament (PCL). The pMFL plays a role in recovery after PCL injuries and offers stability to the lateral meniscus, promoting normal knee function.

Purpose/Hypothesis

The aim of the magnetic resonance imaging (MRI) arm of this study was to evaluate the prevalence of the pMFL in Polish patients. The purpose of the systematic review and meta-analysis was to evaluate the clinical relevance of the pMFL in knee surgery. It was hypothesized that extensive variability exists in reports on the prevalence, function, and clinical significance of the pMFL.

Study Design

Cross-sectional study and systematic review; Level of evidence, 3.

Methods

A retrospective MRI investigation was conducted on 100 randomly selected lower limbs of Polish patients (56 male, 44 female) performed in 2019 to determine the prevalence of the pMFL. Additionally, an extensive literature search of major online databases was performed to evaluate all reported data on the pMFL. Assessments of article eligibility and data extraction were completed independently by 2 reviewers, and all disagreements were resolved via a consensus. A quality assessment of the included articles was performed using the Anatomical Quality Assessment tool.

Results

In the MRI arm of this study, the pMFL was observed in 73 of the 100 limbs. In the meta-analysis, 47 studies were included, totaling 4940 lower limbs. The pooled prevalence of the pMFL was found to be 70.4% (95% CI, 63.4%-76.9%); the mean length was 27.7 mm (95% CI, 24.8-30.5 mm) and the mean widths were 4.5, 6.1, and 4.1 mm for the meniscal and femoral attachments and midportion, respectively. The mean pMFL thickness was 2.3 mm (95% CI, 1.8-2.7 mm).

Conclusion

Despite the variability in the literature, the pMFL was found to be a prevalent and large anatomic structure in the knee joint. The shared features of this ligament with the PCL necessitate the consideration of its value in planning and performing arthroscopic procedures of the knee.

Clinical results after surgical treatment of posterolateral tibial plateau fractures ("apple bite fracture") in combination with ACL injuries

PURPOSE

The anterior cruciate ligament (ACL)-tear is a common injury in orthopaedic trauma. Depending on the energy of impact fractures of the posterolateral tibial plateau are often associated. Different morphologic variants of posterolateral tibial plateau impaction fractures have been described in the setting of an ACL-tear. Up to now an algorithm of treatment for a combined injury of a posterolateral tibial head fracture and an injury to the anterior cruciate ligament is missing.

METHODS

We present a retrospective study with clinical and radiological analysis of posterolateral fractures in combination with ACL-tear. Impressions with a depth of more than 2 mm and/or a width that outreaches more than half of the posterior horn of the lateral meniscus with additional 3. degree positive pivot-shift-test indicated surgical treatment of the fracture with additional ACL repair or reconstruction. Clinical evaluation included follow-up examination, Visual Analog Scale (VAS), International Knee Documentation Committee Score (IKDC), functional and radiological Rasmussen score.

RESULTS

20 patients were included with a mean age of 43.6 ± 12.4 years. Mean follow-up was 18,2 ± 13,5 months. The fracture was arthroscopically reduced and percutaneously fixed with a screw osteosynthesis (Group 1), reduced via a dorsal approach without (Group 2) or with an autologous bone graft (Group 3). Subjective IKDC score was 79,15 ± 6,07. Functional Rasmussen scores ranged from 27 to 30 (mean 28 ± 2.71). Radiological Rasmussen scores ranged from 16 to 18 points (mean 16.75 ± 1.33). According to IKDC score (p = 0.60), functional Rasmussen score (p = 0.829) and radiological Rasmussen score (p = 0.679) no significant discrepancy between the groups were seen. There was no failure of the ACL graft recorded.

CONCLUSIONS

Posterolateral tibial plateau fractures in combination with an ACL-tear, can cause persistent instability and increase rotational instability. Indication for treatment of these fractures is still under debate. From the biomechanical aspect the lack of more than 50% of the posterior horn of the lateral meniscus and dislocation/depression of more than 2 mm results in an increased rotational instability of the ACL deficient knee. Combined surgical treatment with ACL repair or reconstruction is a safe procedure that results in good, short-term clinical outcome, if our algorithm is followed. In addition this study shows, that majority of posterolateral tibial plateau fractures can be treated arthroscopically.

High-Grade Posterolateral Tibial Plateau Impaction Fractures in the Setting of a Primary Anterior Cruciate Ligament Tear Are Correlated With an Increased Preoperative Pivot Shift and Inferior Postoperative Outcomes After Anterior Cruciate Ligament Reconstruction

BACKGROUND

Impaction fractures of the posterolateral tibial plateau have been previously described to occur in association with anterior cruciate ligament (ACL) tears; however, the effect of these injuries on patient-reported outcomes (PROs) after ACL reconstruction (ACLR) is not well known.

PURPOSE

(1) To assess the effect of posterolateral tibial plateau impaction fractures on preoperative clinical knee stability assessed by the Lachman and pivot-shift examinations and (2) to assess the effect of impaction fractures on PROs after ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients undergoing ACLR for primary ACL tears with available magnetic resonance imaging (MRI) scans were included in this study. MRI scans were reviewed for the presence of posterolateral tibial plateau impaction fractures, which were classified according to the morphological variant. Associations with clinical laxity determined by an examination under anesthesia were assessed using binary logistic regression. Also, 2-year postoperative PROs (12-Item Short Form Health Survey [SF-12] Mental Component Scale and Physical Component Scale [PCS], Lysholm, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Tegner scores) were modeled using multiple ordinal logistic regression to assess the effect of posterolateral tibial plateau impaction fracture classification while adjusting for other covariates. Pearson correlation coefficients (PCCs) were used to assess for correlations between postoperative PROs and the amount of tibial plateau bone loss present.

RESULTS

Displaced posterolateral tibial plateau impaction fractures were present in 407 (49.3%) of 825 total knees included in this study. Knees with type IIIB impaction fractures had an increased likelihood of having a high-grade pivot shift (odds ratio, 2.3; P = .047), with no other impaction fracture types showing a significant association. There were no significant associations between posterolateral tibial plateau impaction fracture type and a higher Lachman grade. Of the 599 eligible knees with 2-year follow-up, postoperative information was obtained for 419 (70.0%). Patients improved in all PROs at a mean of 3.0 years after ACLR (P < .001). Multiple ordinal logistic regression demonstrated a posterolateral tibial plateau impaction fracture as an independent predictor of the postoperative Lysholm score, with higher grade impaction fractures showing decreased Lysholm scores. Pearson correlation testing demonstrated weak but statistically significant correlations between sagittal bone loss of posterolateral tibial plateau impaction fractures and SF-12 PCS (PCC = -0.156; P = .023), WOMAC total (PCC = 0.159; P = .02), Lysholm (PCC = -0.203; P = .003), and Tegner scores (PCC = -0.151; P = .032).

CONCLUSION

When classified into distinct morphological subtypes, high-grade posterolateral tibial plateau impaction fractures were independently associated with decreased postoperative outcomes after ACLR when controlling for other demographic or clinical variables. Patients with large depression-type posterolateral tibial plateau impaction fractures (type IIIB) had an increased likelihood of having high-grade pivot-shift laxity on clinical examination under anesthesia.

Arthroscopically assisted and three-dimensionally modeled minimally invasive rim plate osteosynthesis via modified anterolateral approach for posterolateral tibial plateau fractures

AIM

The aim of this study was to describe a new, closed, arthroscopically-assisted reduction of posterolateral tibial plateau fractures with minimally invasive plate osteosynthesis using a plate pre-contoured over a 3D-model based on a CT-scan of the injured tibial plateau and positioned by using a minimal anterolateral approach.

METHODS

A five to six centimeter long curvilinear incision was made over the Gerdy's tubercle. After subcutaneous dissection, the fascia was incised, the ileo-tibial band was split, and the dissection was extended posteriorly. The knee was flexed to 90° and the space between the fibular collateral ligament and the posterolateral plateau rim (para-FCL space) was created. A variable-angle locking compression plate contoured on a 3D-model was inserted flush to the tibial plateau rim. Two cortical screws were placed to ensure support under the area of depression as far posteriorly as possible. Two additional screws were implanted, and a cortical screw was used for the most anterior screw hole. The custom pre-contoured plate based on a person-specific 3D-model, associated with arthroscopy reduction, provides a supporting and containing effect to the posterolateral periarticular fragments and allows a minimally invasive plate osteosynthesis fixation to be performed. This guarantees a proper reduction and fixation without the described limitations and risks associated with the classic approaches.

CONCLUSIONS

This approach should be considered to treat fractures of the posterolateral plateau, isolated or associated with medial tibial plateau fractures, as it could improve the outcome in terms of lower associated risks, better reduction and fixation, and faster and improved patient recovery.