Introduction: Patellar fractures account for 1% of all fractures. Fractures of the patella occur from either a direct impact or eccentric contraction of the extensor mechanism. Treatment is dependent on the fracture pattern, displacement, articular surface congruity, and the status of the patient’s extensor mechanism. Several techniques have been described for patellar fracture fixation.
Case Report: We present a case of a 60-year-old female who had a segmental fracture of the patella that included a small distal pole fragment. Initially, the fracture was fixed with lag screw fixation of the two major fragments. Subsequently, the small inferior pole fragment was fixed to the proximal construct with three-bone tunnel suture fixation technique.
Conclusion: This stable construct enabled us to start the patient on an early range of motion exercise program and has resulted in a good functional result at second-year follow-up. To our knowledge, this type of bony construct has not been reported before.

Keywords: Knee, Orthopedics, Patella fractures, Patella, Trauma

Patellar fractures account for 1% of all fractures. Fractures of the patella occur from either a direct impact or eccentric contraction of the extensor mechanism. Treatment is dependent on the fracture pattern, displacement, articular surface congruity, and the status of the patient’s extensor mechanism. Several techniques have been described for patellar fracture fixation. They include tension band fixation, cannulated screws, plating, etc. In severely comminuted fractures, partial patellectomy with restoration of the extensor mechanism may be the only treatment option. However, partial patellectomy is associated with several complications; shortening of the extensor mechanism, increased patellofemoral joint forces, and subsequent patellofemoral arthritis.

A 60-year-old female presented to our institution with a complaint of right knee pain after she had slipped and fallen onto her right knee. Radiographs revealed a segmental patellar fracture as shown in Figure 1A–C . A midline incision was made centered over the patella. The patella was found to have a large proximal fragment, a medium sized middle fragment, and a small distal pole fragment attached to the patellar tendon. There was also rupture of the medial and lateral patellar retinacula.

Inspection of the fracture ends revealed comminution and bone loss. K-wires and reduction clamps were used to hold the provisional reduction between the proximal and middle segments of the patella. A 2.7 mm screw was used, via lag technique, to secure the proximal and middle fragments of the patella. Next, Krackow stitches using #5 FiberWire were placed through the patellar tendon, incorporating the inferior pole of the patella. Three bone tunnels were drilled through the proximal and middle fragments and the suture ends of the Krackow stitch were passed through the drill holes exiting the superior pole of the patella. The sutures ends were tied and buried under the quadriceps tendon. Under fluoroscopy, the knee was taken through flexion and extension and was found to be stable. The medial and lateral patellar retinacula were repaired using #2 FiberWire suture. Immediate postoperative radiographs are shown in Figure 2A–B.

Postoperatively, the patient was made weight bearing as tolerated in a knee immobilizer for six weeks. The range of motion was started two weeks after surgery. At her second-year follow-up, the patient has painless knee extension of 0 degrees and knee flexion of 120 degrees, comparable to the contralateral side. Radiographs at final follow-up show a healed patella with no visible fracture lines (Figure 3A–C). Clinical photos of the patient’s range of motion are shown in Figure 4.

There have been several techniques described for the treatment of patella fractures. In comminuted fractures, management with inferior pole resection can result in patella baja and shortening of the extensor mechanism. Patella baja can lead to an increase in the compressive forces across the patellofemoral joint, potentially increasing cartilage wear within the patellofemoral joint, [1][2] leading to early arthritis.

Advances in suture material strength and bone anchor techniques have provided sufficient strength for early mobilization after patellar tendon repair [3][4]. However, in patella fractures with distal comminution or avulsion fractures, bone anchors are not recommended because the purchase of the bone anchor depends on having an intact cortex [4]. In cases where there is no intact cortex or insufficient bone stock is present, excising the bone fragments with attachment of the patellar tendon by transosseous pull out suture also requires a considerable period of immobilization of the knee in order for healing to occur due to the weakness of synthetic non-absorbable sutures [5]. The tendon-to-bone junction requires at least six weeks to heal after a partial patellectomy [6]. This immobilization of the knee in extension delays rehabilitation, can result in weakness of the quadriceps muscle, and decreased functional restoration of knee range of motion [7].

In order to avoid delays in rehabilitation, techniques such as figure-of-eight wiring and patellotibial tubercle cerclage reinforcement have been described. The use of wiring may lead to implant failure, implant irritation, and the need for a secondary procedure. These techniques also make adjusting the length of the patellar tendon difficult, potentially leading to patella baja and increased patellofemoral joint wear [5][6] [7][8]. In order to promote early knee mobilization Hung et al. [6] reinforced their patellar tendon-to-bone repair with a figure-of-eight tension band wire loop from the patella down to the tibial tubercle. The majority of the patients in their series were mobilized after one week. Though none of the patients had disruption of the repair, a high percentage did have radiographic arthritis at final follow-up likely due to the partial patellectomy. Breakage of the tension band wire is also a concern. Retaining the inferior patellar pole preserves the functional length of the extensor mechanism resulting in better functional outcomes regardless of fixation method [7].

With our technique, we were able to provide the patient with a stable construct, early range of motion, and good long-term results. To our knowledge, this type of bony construct has not been reported before.

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