Clinical and functional outcomes of fracture pattern-driven plate osteosynthesis technique for comminuted patellar fractures using multiple miniplates

Abstract

Introduction: Comminuted patellar fractures, particularly AO/OTA 34-C2 and C3 fractures, present substantial challenges in achieving stable fixation and anatomical reconstruction. Conventional tension-band wiring may fail in such cases due to insufficient mechanical stability. This study aimed to evaluate the clinical and functional outcomes of a fracture pattern-driven plate osteosynthesis technique using multiple miniplates tailored to the intricate morphology of multifragmentary patellar fractures.

Methods: A retrospective review was conducted of 62 patients with AO/OTA 34-C2 or C3 patellar fractures treated between 2018 and 2023 at two academic trauma centers. All patients underwent fixation using a fragment-specific approach involving anterior tension-band plating and miniplates, guided by preoperative CT-based fracture mapping. The outcome measures included radiographic reduction quality, union rate, range of motion (ROM), Lysholm score, and isokinetic quadriceps strength at 6 and 12 months.

Results: Anatomical or good reduction was achieved in all cases (72.6% anatomical, 27.4% good), with a 100% union rate and low complication rate (3.2% reoperation rate). The mean final ROM was 132.9° ± 6.8°, and Lysholm scores improved from 70.3 ± 10.0 at 6 months to 89.1 ± 6.7 at 12 months. However, isokinetic peak torque deficits persisted at 12 months (mean 24.6% ± 13.0), and the body mass–normalized extension torque averaged 0.99 ± 0.40 Nm/kg, indicating residual muscle weakness despite rehabilitation.

Conclusion: The fracture-pattern-driven osteosynthesis technique using multiple miniplates offers a reliable method for managing complex patellar fractures, providing excellent reduction quality, high union rates, and satisfactory functional outcomes. This approach enables individualized fixation strategies tailored to fragment morphology. Despite good clinical recovery, persistent deficits in quadriceps strength highlight the need for prolonged rehabilitation beyond 12 months to achieve complete functional restoration.

Keywords: Comminuted fracture; Fragment-specific fixation; Miniplate fixation; Patellar fracture; Plate osteosynthesis; Quadriceps strength.

Fig. 1

The primary horizontal fracture lines (red dotted lines), secondary horizontal fracture lines (purple dotted lines), and medial and lateral secondary vertical fracture lines (blue dotted lines) were identified as major fracture lines. a The major fracture lines from the previous study are as follows: primary horizontal fracture lines (red dotted line), secondary horizontal fracture lines (purple dotted line), and medial and lateral secondary vertical fracture lines (blue dotted line). b The main coronal fracture line (black dotted line) and horizontal fracture line produce coronal split fragments by linking. pH primary Horizontal, sH secondary Horizontal, sV secondary Vertical, S Satellite, I Inferior, mC main Coronal, Ca Coronal anterior, Cp Coronal posterior, Ia Inferior anterior, Ip Inferior posterior

Fig. 2

a A 62-year-old female patient diagnosed with AO/OTA 34-C3 associated with coronal split fractures. b Fracture lines and fragments were indicated based on the patellar fracture analysis. c The primary horizontal fracture line is located on the middle level of the patella (red arrow), and the secondary fracture line is located on the lower boundary of the patella (purple arrow). The main coronal fracture line (arrowhead) separated the anterior and posterior coronal fragments. d Intraoperatively, those coronal fragments were split. pH primary Horizontal, sH secondary Horizontal, sV secondary Vertical, S Satellite, I Inferior, mC main Coronal, Ca Coronal anterior, Cp Coronal posterior

Fig. 3

a The 1.5 mm strut-type mini plate from the 1.5 mm Compact Hand Set (DePuy Synthes, USA) was slightly over-bent before application. b The satellite proximal and distal fragments were stabilized with anterior 1.5 mm strut-type (arrowhead) and T-shape mini plates. P proximal, S satellite, Ca Coronal anterior, I inferior

Fig. 4

a The primary horizontal fracture was widely displaced. b After taking out the posterior coronal free articular fragment from the distal fracture segment, it was reduced and fixed with two 1.5 mm embedded screws(arrowhead) using the backward flip approach. c Reduction of primary horizontal fracture using pointed reduction clamp (d) Stabilization by anterior 1.5 mm strut-type reduction plate (black and white arrow). P proximal, Ca Coronal anterior, Cp Coronal posterior, I inferior

Fig. 5

a A 57-year-old female patient diagnosed with AO/OTA 34-C3 associated with coronal split fractures with impaction. The width of distal fragments (dotted blue line) was decreased compared with that of proximal fragments. (blue line) (b) Dis-impaction using curved mosquito clamp or osteotome. c Morselized chip bone graft (d) Stabilization with Anterior to posterior direction screws afterward through the 1.5 mm anterior reduction plate (black arrow). P proximal, Ca Coronal anterior, Cp Coronal posterior, I inferior, + Morselized chip bone

Fig. 6

a The 2.4 mm (Compact Hand Set; DePuy Synthes, USA) or 2.0 mm (Arix Hand System; Jeil Medical, Republic of Korea) T-type plate (arrow head) was slightly overbent. b After creating a 2.0 cm incision in the patellar tendon, the plate was advanced beneath the tendon, positioning the three-holed head of the plate under the inferior pole. c A ball-tip clamp or Weber clamp was used to press the plate firmly to enhance compression on the inferior pole fragment created by the secondary horizontal fracture line. d The insertion of two conventional cortical screws across the primary horizontal fracture line to provide dynamic compression and secure the plate against the anterior patellar cortex. An additional locking screw was then inserted into the proximal fragment

Fig. 7

a Postoperative radiographs show the tension-band plating with multiple mini plates. All identified fragments were anatomically stabilized. There was no articular step-off showing anatomical reduction. b After 6 months, the radiologic bony union was achieved, and the range of motion was fully recovered

Fig. 8

A 52-year-old male patient diagnosed with AO/OTA 34-C3 associated with anterior and posterior coronal split fractures in the distal fragment. Two comminuted posterior coronal fragments were reduced and fixed with two 1.5mm embedded screws and two 1.4mm K-wires on the proximal fragment through a forward flipping technique. Cp coronal posterior Ca coronal anterior