Plating as salvage for failed treatment of patellar fractures Kancherla, Vamsi K. MD; Nwachuku, Chinenye O. MD Department of Orthopaedic Surgery, St. Luke’s University Health Network, Bethlehem, Pennsylvania

INTRODUCTION Patellar fractures can be challenging injuries and despite excellent fixation, poor outcomes can still occur. Historically, treated nonoperatively or with partial or total patellectomy, such fractures are now treated by tension band constructs to improve extensor mechanism strength and efficiency. Tension band fixation, however, does not always lead to excellent outcomes. Reports of knee pain, construct failure, symptomatic hardware, and functional limitation leave room for improvement in techniques.

Several biomechanical studies over the last few years have come to support plate osteosynthesis, citing improved load to failure and reduced fracture gapping all the while remaining low profile. A few reports have described success from plating the inferior pole of the patella using a minifragment or basket plate. A cage or mesh plate to allow for articular visualization, multifragment anatomic fixation, preservation of patellar vascularity, and suture capture of the quadriceps or patellar tendons to the plate. The proposed advantages of plate osteosynthesis have thus been thought to lead to enhanced rehabilitation and improved clinical outcomes.

A case of tension band fixation of a patellar fracture that failed twice in a young.

CASE REPORT A 31-year-old man sustained a right patellar fracture that underwent tension band fixation with cannulated screws at an outside hospital. This construct failed 1 mo later requiring revision fixation with cannulated screws. Five months after the revision procedure, while running during a softball game, the patient felt a sudden pop in his right knee with immediate pain, swelling, and inability to bear weight. Upon presentation to our institution, multiview radiographs of the right patella showed failure of the cannulated screw tension band construct with noted osteopenia and a bent screw (Figure 1A and B). The right knee was aspirated for pain relief (110 ccs of blood) and placed in an extension knee immobilizer. After medical evaluation of the patient’s vWD and initiation of desmopressin, consent was obtained for revision fixation of a comminuted patellar fracture nonunion.

Using the prior longitudinal incision across the knee, the patient’s fracture was exposed using medial and lateral flaps. After removal of the bent Synthes 4.0-mm cannulated screws (Synthes; West Chester, PA), reduction was performed using pointed reduction clamps, held with Kirschner wires, and the fracture was fixed with larger Synthes 4.5-mm partially threaded cannulated screws . Tension banding was then performed with a wire. Given the amount of osteopenia and in the setting of prior revision surgery, a Synthes 2.4 mm/2.7 mm Variable Angle Locking Mesh Plate was utilized for augmentation, which allowed for circumferential stabilization of the patella, multifragment capture with a combination of locking and nonlocking screws, and neutralization of forces across the cannulated screws. patient was placed in a hinged knee brace locked in extension and allowed weight bearing to tolerance with crutches for assistance.

At the 2-week follow-up visit, the patient had painless weight bearing with the hinged knee brace locked in extension. At the 6-week follow-up visit, the hinged knee brace was unlocked to allow physical therapy and initiate range of motion (ROM) from 0-40 degrees with an increase of 30 degrees every 2 wk thereafter. Radiographs at the 2-week and 6-week visits showed a stable construct. At the 3.5-month follow-up visit, the patient did not complete his therapy but had been performing range of motion exercises by himself. He was instructed to discontinue the brace and start strengthening. He continued to have zero pain, full knee extension, 5/5 quadriceps and hamstrings strength, and active range of motion from 0-135 degrees . Radiographs continued to show appropriate fracture healing without evidence of implant loosening/failure

DISCUSSION Tension band fixation has long been the accepted standard for patellar fractures despite the lack of strong randomized evidence. With the advent of fixed-angle plating through locking technology and a low-profile design, osteosynthesis of patellar fractures with a plate has been at least biomechanically noninferior 3 or better than the traditional tension band construct.

The application of a mesh plate that can be cut and contoured to match the needs of any patellar fracture allows for intraoperative flexibility while also allowing for increased opportunity through numerous screw holes for multifragment fixation and suture augmentation to adjacent tendon or retinaculum. Such a design can be applied in compression or neutralization with the goal of reducing any further strain and achieving absolute stability. Additionally, given that the majority of the blood supply to the patella emanates from the inferomedial pole and a deep peripatellar anastomotic ring, lateral placement of a plate can preserve this blood supply without losing the flexibility provided by numerous screw holes and trajectories.

While recent clinical studies have supported the use of a plate for primary patellar fixation none have demonstrated clinical outcomes from revision surgery in a challenging case such as our patient with an underlying bleeding disorder and a likely nonunion. Decrease in the time of consolidation in almost all the bone fractures in the operated group. Supported the potential for delayed union, wound infection, and hematoma.

In the largest series to date on patellar fracture plate fixation,  found favorable clinical results for their cohort of nine female patients (mean age 65 yr) with an average follow-up of 18 mo from index fracture fixation. At follow-up, the mean visual analog score was 8, the Short-Form-36 (SF-36) Physical Component Score (PCS) was 50, the SF-36 Mental Component Score (MCS) was 56, range of motion was 0-143 degrees, and time to union was 23 wk. No patient developed avascular necrosis (AVN), infection, or wound complications. One patient did require hardware removal at 13 mo for symptomatic hardware. Our patient achieved a similar clinical outcome after following a careful, graduated postoperative rehabilitation protocol.

In the patient with an underlying history for poor healing or evidence of fracture fixation failure, plate osteosynthesis can be a biomechanically effective and a clinically reliable surgical strategy in isolation or in addition to a tension band construct.

REFERENCES : Lorich DG, Warner SJ, Schottel PC, et al. Multiplanar fixation for patella fractures using a low-profile mesh plate. J Orthop Trauma. 2015; 29:e504–e510. Bibliographic Links [Context Link] Taylor BC, Mehta S, Castaneda J, et al. Plating of patella fractures: techniques and outcomes. J Orthop Trauma. 2014; 28:e231–e235. Bibliographic Links [Context Link] Dickens AJ, Salas C, Rise L, et al. Titanium mesh as a low-profile alternative for tension-band augmentation in patella fracture fixation: A biomechanical study. Injury. 2015; 46:1001–1006. Bibliographic Links [Context Link]