Anterior variable-angle locked plating versus tension band wiring of simple and complex patella fractures - a biomechanical investigation

Lateral rim variable angle locked plating versus tension band wiring of simple and complex patella fractures: a biomechanical study

INTRODUCTION

Treatment of both simple and complex patella fractures is a challenging clinical problem. Although tension band wiring has been the standard of care, it can be associated with high complication rates. The aim of this study was to investigate the biomechanical performance of recently developed lateral rim variable angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

MATERIALS AND METHODS

Sixteen pairs of human anatomical knees were used to simulate either two-part transverse simple AO/OTA 34-C1 or five-part complex AO/OTA 34-C3 patella fractures by means of osteotomies, with each fracture model created in eight pairs. The complex fracture pattern was characterized by a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral, and an inferior (central distal) fragment mimicking comminution around the distal patellar pole. The specimens with simple fractures were pairwise assigned for fixation with either tension band wiring through two parallel cannulated screws or a lateral rim variable angle locking plate. The knees with complex fractures were pairwise treated with either tension band wiring through two parallel cannulated screws plus circumferential cerclage wiring or a lateral rim variable angle locking plate. Each specimen was tested over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive knee flexion within the range of 90° flexion to full extension. Interfragmentary movements were captured via motion tracking.

RESULTS

For both fracture types, the articular displacements measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following the lateral rim variable angle locked plating compared with tension band wiring, p ≤ 0.01.

CONCLUSIONS

From a biomechanical perspective, lateral rim variable angle locked plating of both simple and complex patella fractures provides superior construct stability versus tension band wiring under dynamic loading.

Comparative study of locking neutralization plate construct versus tension band wiring with a cannulated screw for patella fractures: experimental and finite element analysis

Transverse patella fractures, accounting for approximately 1% of Orthopedic injuries, pose intricate challenges due to their vital role in knee mechanics. This study aimed to compare the biomechanical performance of a construct, integrating cannulated screws and an anterior locking neutralization plate, with the conventional tension band wiring technique for treating these fractures. Experimental testing and Finite Element Analysis were employed to evaluate the constructs and gain profound insights into their mechanical behavior. Sixteen cadaveric knees were prepared, and transverse patella fractures were induced at the midpoints using a saw. The plate construct and tension band wire fixation were randomly assigned to the specimens. A cyclic test evaluated the implants' durability and stability, simulating knee movement during extension and flexion. Tensile testing assessed the implants' maximum failure force after cyclic testing, while Finite Element Analysis provided detailed insights into stress distribution and deformation patterns. Statistical analysis was exclusively performed for the experimental data. Results showed the plate enhanced stability with significantly lower deformation (0.09 ± 0.12 mm) compared to wire fixation (0.77 ± 0.54 mm) after 500 cycles (p = 0.004). In tensile testing, the construct also demonstrated higher failure resistance (1359 ± 21.53 N) than wire fixation (780.1 ± 22.62N) (p = 0.007). Finite Element Analysis highlighted distinct stress patterns, validating the construct's superiority. This research presents a promising treatment approach for transverse patella fractures with potential clinical impact and future research prospects. This study presents a promising advancement in addressing the intricate challenges of transverse patella fractures, with implications for refining clinical practice. The construct's improved stability and resistance to failure offer potential benefits in postoperative management and patient outcomes.

A novel suture bridge anchor fixation technique to treat inferior pole fractures of patella: A retrospective clinical study

The traditional surgical methods to the fracture of the inferior patellar fracture include steel wire tension band fixation and inferior patellar resection, which have many disadvantages. In order to overcome the disadvantages of traditional surgery, we innovated and improved the double row anchor suture bridge technology to the treat the inferior patellar fracture. This study is to investigate the method, technique and clinical efficacy of double-row anchor suture bridge technique in the treatment of inferior pole fractures of patella. Between January 2019 and March 2021, 36 patients with inferior pole fractures of patella underwent the surgery with the double-row anchor suture bridge technique. 28 injury cases were caused by falls while 8 injury cases were from car crashes. The operation time, amount of intraoperative bleeding and complications were recorded. Radiological assessments and Bostman score were performed 1, 3, and 6 months post-operation and at the most recent follow-ups. The study sample consisted of 19 males and 17 females, aged 31 to 72 years old. The operation time was (54-76) minutes. All incisions healed in 1 stage. No complications such as incision infection, flap necrosis and nerve injury occurred. Patients in this group were followed up for 10 to 18 months, with an average follow-up of 12 months. All fractures healed in 10 to 20 weeks, with an average healing time of 12 weeks. At the last follow-up, the Bostman score was (27.5 ± 3.3), excellent in 32 cases and good in 2 cases, with an excellent rate of 94.4%. The range of motion of the knee joint was (-2.6 ± 2.0)° when the knee was extended and (122 ± 5.0)° when the knee was bent. The muscle strength of quadriceps femoris was grade 5. Double-row anchor suture bridge technique is applied to inferior pole fractures of patella by virtue of its various effects, such as the complete preservation of the inferior pole fragments during the operation, satisfactory fracture reduction, firm fixation, and meeting patients' requirements for early postoperative ambulation. In summary, double-row anchor suture bridge technique is an ideal surgical procedure for the treatment of the inferior pole fracture of patella with safety, reliability and high satisfaction.