Combined Tibial Tubercle Fracture With Patellar Tendon Avulsion in an Adult: A Rare Case and Novel Fixation Technique

Abstract

Tibial tubercle avulsion fracture with simultaneous patellar tendon avulsion is a rare injury that has only ever been reported in adolescents; the diagnosis and management of this combined lesion has not been described in the adult population. A healthy 62-year-old male presented with acute knee pain and an inability to walk after a fall on ice. Radiographs demonstrated a displaced fracture of the tibial tubercle; patellar tendon integrity could not be verified by ultrasonography. Intraoperatively, the patient was found to have a distal avulsion of the patellar tendon in addition to tubercle fracture. First, the tendon was secured to the tubercle fragment with transosseous sutures. A novel slotted-plate construct was used to fix the tubercle fragment prior to tightening the sutures. Postoperatively, the patient was permitted to bear weight as tolerated with the operative knee immobilized in extension. After six weeks, knee range of motion was gradually increased using a hinged brace. At one year, the patient had achieved excellent range of motion (full extension to 135 degrees of flexion) and strength (5/5 knee flexion and extension) without residual pain or complications. This case represents the first description of diagnosis, management, and rehabilitation of a combined tibial tubercle fracture with distal patellar tendon avulsion in an adult. The unique construct, a slotted-plate over transosseous sutures, provided excellent results and likely has further applications.

Keywords: avulsion fracture; patellar ligament; tendon rupture; tibial tubercle.

Figure 1. Lateral (A) and anteroposterior (B) preoperative radiographs

Avulsion of the tibial tubercle (arrows) and patella alta can be seen; the bony tubercle fragment (arrows) is translated 1.5 cm proximally and is rotated 90º from its anatomic position.

Figure 2. Preoperative ultrasonography

Ultrasound demonstrating tibial tubercle (TT) fracture with proximal migration of the patellar tendon and tubercle fragment. Integrity of the distal patellar tendon could not be determined due to hematoma at the site of tendon attachment to the tibial tubercle (arrow).

Figure 3. Intraoperative images

(A) Free tubercle fragment (in forceps) and tibia donor site (lower arrow) with proximal migration of the patella (upper arrow). (B) Free edge of the avulsed patellar tendon with no remaining bony attachment (arrow). (C) Transosseous sutures through the donor site (metal probe) and tubercle fragment (lower arrow), secured to the patellar tendon with a running-locking technique (upper arrow).

Figure 4. Sequence of plate fixation with final intraoperative appearance

(A) A slotted plate was positioned after transosseous suture placement through tibia, tubercle fragment, and patellar tendon. (B) The plate was then secured atop the tubercle fragment. (C) Primary sutures were tensioned and a third, defunctioning suture (red) was placed through a distal pilot hole and secured to the patellar tendon with a running-locking technique. (D) Completed fixation with the tubercle fragment reduced, plate secured (white arrow, not visible), and the tendon reduced.

Figure 5. Post-fixation radiographs

(A) Intraoperative fluoroscopy demonstrating plate fixation of the tibial tubercle with slots cut in plate (arrows) for passing over sutures. (B) Intraoperative patella alta evident after suture tensioning. (C) Three months postoperative, patella height is appropriate and with visible pilot-hole lucency (arrow) from transosseous suture placement. (D) One year postoperative, slight osseous debris or ossification (arrow) can be seen in the area of the patellar tendon.