Two Cases of Contact Anterior Cruciate Ligament Rupture Combined with a Posterolateral Tibial Plateau Fracture

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.

Revisiting the flexion-valgus type unicondylar posterolateral tibial plateau depression fracture pattern: classification and treatment

OBJECTIVE

This study aimed to reclassify posterolateral tibial plateau fractures caused by a flexion-valgus force and describe this fracture pattern to provide a relatively programmed surgical treatment based on morphological characteristics that may improve reduction and stabilization.

METHODS

We retrospectively reviewed the fracture pattern and injury mechanism of patients with posterolateral tibial plateau fractures who underwent surgery at the First Affiliated Hospital of Nanjing Medical University between January 2014 and April 2020. The cohort was divided into three types. Type I was a depression fracture of the posterolateral platform with an intact posterolateral cortex. Type II was a depression fracture of the posterolateral platform with a disrupted posterolateral cortex. Type III was a depression fracture of the posterolateral platform in combination with anterior cruciate ligament (ACL) rupture or tibial insertion avulsion fracture of the ACL. The lateral window of the modified Frosch approach with an L-type locking plate was used for patients with type I and type III fractures. For patients with type II fractures, both lateral and posterolateral windows of the modified Frosch approach were used for surgery, and a T-plate on the posterior side with an L-plate on the lateral side were used for fixation. The Rasmussen radiology scoring was used to evaluate the quality of surgical reduction and the Rasmussen functional scoring evaluation standard was used to evaluate knee joint function.

RESULTS

A total of 69 tibial plateau fractures (36 male, 33 female) involving the posterolateral platform were discovered and included in this study. All patients suffered flexion-valgus force at the moment of the accident. There were 32 cases of Type I fracture, 28 cases of Type II fracture, and 9 cases of Type III fracture. The patients were followed up for 12-30 (mean 20.8 ± 9.4) months. The postoperative Rasmussen radiological scores for the three types of fractures were 15-17 (mean 16.31 ± 0.78), 14-17 (mean 15.93 ± 0.94), and 14-17 (mean 16.22 ± 0.97), respectively. The postoperative Rasmussen functional scores for the three types of fractions were 27-30 (mean 27.97 ± 0.90), 27-29 (mean 27.36 ± 0.56), and 27-29 (mean 27.56 ± 0.73), respectively.

CONCLUSION

Flexion-valgus posterolateral tibial plateau fractures were divided into three types based on the integrity of the posterolateral wall and ACL injuries. We hope the classification can play a certain reference role in recognizing and treating flexion-valgus-type posterolateral tibial plateau fractures.

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.

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.

A case report of multi-ligaments injury of the ACL-MCL-PT combined with an occult fracture of the posterolateral tibial plateau

The anterior cruciate ligament and medial collateral ligament are important static stabilizers of the knee. The patellar tendon is part of the knee extensor mechanism. The injury simultaneously involving these three structures is very rare. This paper reports a case with simultaneous ipsilateral rupture of the anterior cruciate ligament, medial collateral ligament, patellar tendon, and an occult compression fracture of the posterolateral tibial plateau. This injury pattern has not been reported in literature yet. The injury mechanism was hypothesized as a sudden anterior translation and valgus of the proximal tibia when the knee was in high flexion, followed by an eccentric quadriceps' contracture. In the followed management, ruptured medial collateral ligament and patellar tendon were sutured with augment, while the torn anterior cruciate ligament and fracture were treated conservatively. The outcome of the treatment was satisfactory, and no complication was observed. To this combined injury, a comprehensive consideration, including physical examination, multiple imaging examinations, and analysis of injury mechanism, is essential for a full diagnosis and treatment decision. Especially, computed tomography may help to identify an occult or non-displaced fracture, which would be easily misdiagnosed when nothing unusual was found in routine X-rays. In the treatment, it is suggested to perform a selective or step-by-step repair to the damaged structures, rather than an immediate total repair after injury.

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.

An Arthroscopic Procedure for Restoration of Posterolateral Tibial Plateau Slope in Tibial Plateau Fracture Associated With Anterior Cruciate Ligament Injuries

High-energy anterior cruciate ligament (high-energy ACL) injury, occurring in high-energy rotatory trauma of the knee, can accompany a unique fracture pattern that involves depression of the slope of the posterolateral tibial plateau (PLTP). These injuries are challenging to manage due to the lack of a gold-standard arthroscopic procedure that addresses both ACL deficiency and depressed PLTP slope. In such injuries, a one-stage approach may be used to (1) reconstruct the ACL or (2) reduce and fix the avulsed tibial spine, while concomitantly performing an arthroscopy-assisted reduction of a PLTP fracture that restores the anatomic slope of the tibial plateau. To summarize, using combined arthroscopic and fluoroscopic visualization, a tibial tunnel reaching 1 cm distal to the depressed plateau fragment is created using a cannulated drill. The drill is used to punch up the depressed fragment to its anatomic location, restoring the original slope of the PLTP. The corrected slope is then fixed in situ using a press-fit fibular allograft to stabilize the corrected PLTP slope. Use of this minimally invasive arthroscopic technique to restore the PLTP slope may help prevent graft failure of the reconstructed ACL and improve patient outcomes.

Anterior Cruciate Ligament Rupture with Medial Collateral Ligament Tear with Lateral Meniscus Posterior Root Tear with Posterolateral Tibia Osteochondral Fracture: A New Injury Tetrad of the Knee

INTRODUCTION

Injuries to the knee ligaments, menisci, and cartilage are possible in high-velocity trauma as in road traffic accidents. Similarly, these structures can be disrupted in proximal tibia fractures. We present a series of three cases which had a previously undescribed injury combination.

CASE PRESENTATION

The first and second patients presented primarily to us following fall from motorbikes. Both these patients had injuries of the anterior cruciate ligament (ACL), medial collateral ligament (MCL), lateral meniscus body and posterior root tear, and osteochondral fracture of posterolateral tibia. The osteochondral fracture was managed by internal fixation with headless compression screws. The ligaments were either repaired or reconstructed and meniscus root tear was treated by transtibial pull through repair. The third patient also had the same injury but was treated at another center. He presented with early arthritis of the lateral tibiofemoral joint and valgus malalignment. Treatment for him was in the form of lateral distal femur open-wedge osteotomy and MCL reconstruction. All three patients had good outcome at the end of 1year.

CONCLUSION

We report a new injury tetrad of ACL tear, MCL tear, lateral meniscus posterior root tear, and posterolateral tibia osteochondral fracture. The mechanism of injury is most likely a violent external rotation and anterior translation of the tibia with a valgus directed force during impact. The treatment of this injury can be performed in single or two stages based on the merits of the case. Anatomic reduction and fixation of the fracture takes precedence to avoid later devastating sequel for the knee.

Arthroscopic Controlled Closed Reduction and Percutaneous Fixation of Posterolateral Tibia Plateau Impression Fractures

Posterolateral impression fractures of the tibial plateau are common, and open reduction and fixation can be demanding, including exposure of the peroneal nerve. Based on a patient example, the surgical technique of an arthroscopic controlled closed reduction and percutaneous screw fixation of a posterolateral tibia plateau impressed fracture is described. A patient sustained a posterolateral impression currently described as an "apple bite" fracture of the tibial plateau. The surgical technique includes standard arthroscopic portals and posteromedial and (transseptal) posterolateral portals. The posterolateral tibial plateau is visualized by incision of popliteomeniscal fibers, retraction of the popliteus tendon, and exposure of the posterolateral plateau. The impression area is marked with a K-wire using an anterior cruciate ligament target device. A cannulated ram is placed over the K-wire. The fracture is lifted under arthroscopic guidance and can be supported with allograft bone chips. To stabilize the reduction, 3 K-wires are positioned from anterior to posterior, and 3 cannulated screws are inserted directly under the joint surface to support the fractured area. In comparison with open surgical techniques, this procedure is exclusively performed under arthroscopic control and enables an anatomic reduction and fixation of the posterolateral tibial plateau.

Displaced osteochondral fracture of the posterolateral tibial plateau associated with an acute anterior cruciate ligament injury

An osteochondral fracture of the posterolateral tibial plateau associated with an anterior cruciate ligament (ACL) injury in a 24-year-old boy is reported. Anterior cruciate ligament rupture is accompanied by bone contusions resulting from the impact of the posterolateral tibial plateau on the anterior part of the lateral femoral condyle. The osteochondral fracture of the posterolateral tibial plateau matched the site where the bone bruise is observed.