Incidence and pattern of technical complications in balloon-guided osteoplasty for depressed tibial plateau fractures: a pilot study in 20 consecutive patients

Depressed tibial plateau fractures remain technically demanding for orthopaedic trauma surgeons [1‐3]. The main challenges consist of achieving anatomic joint reduction in conjunction with stable fracture fixation, to allow early range of motion of the knee, with the aim of achieving good functional outcomes [4]. Further limitations include the risk of a residual intra-articular step-off after insufficient articular reduction [5], and the adequacy of bone grafting options to fill the metaphyseal void after fracture reduction with conventional bone tamps [6‐9]. Recent advances in technique include less-invasive approaches in conjunction with stable fixation using a new generation of angular-stable implants [10, 11], and the appealing option of arthroscopy-guided fracture reduction and fixation [12, 13]. Balloon-guided minimal-invasive fracture reduction, using an inflatable bone tamp, represents a “cutting edge” emerging technique which has been recently described in numerous publications [14‐19]. The advantages of this new technique are intuitive, by (1) minimal-invasive percutaneous approaches which preserve the soft tissue envelope and avoid the necessity of a formal open arthrotomy, (2) by allowing a controlled gradual elevation of the depressed articular fracture fragment under fluoroscopic or arthroscopic guidance and (3) thanks to a large surface area, by allowing small fragments to be elevated simultaneously [15, 16]. A further advantage, as described for the technique of balloon-guided kyphoplasty for vertebral fractures, consists in the creation of a cancellous bone void which allows a safe distribution of fluid-phase bone cement without pressure-induced leakage into the surrounding tissues [20]. The use of fast-setting calcium phosphate appears to represent a safe and efficient technique for filling the metaphyseal void and providing adequate support for the articular surface to prevent secondary subsidence [14, 16]. However, as with any appealing new surgical technique, the early enthusiasm regarding potential benefits must be critically weighed against potential complications and the risk of inducing patient harm on the surgical “learning curve” until a new technique is well established and validated [21]. To date, the available evidence supporting the concept of balloon-guided reduction of tibial plateau fracture is restricted to cadaveric studies, anecdotal case reports, and “expert opinion” technical notes [14‐18]. Indeed, we have yet to demonstrate the supremacy of this new minimal-invasive technique, compared to the use of traditional bone tamps in “standard” open approaches, in prospective, controlled trials.

The present study was designed to analyze and report the rate and pattern of technical complications in a pilot series of 20 consecutive patients treated by inflation osteoplasty for depressed tibial plateau fractures at an academic level 1 trauma center.

This study was designed as a retrospective review of a prospective database of patients undergoing balloon-guided inflation osteoplasty for depressed tibial plateau fractures between October 1, 2010, and December 1, 2012. Indications consisted of partial articular (B-type) depressed lateral or medial tibial plateau fractures amenable to balloon-guided reduction (Schatzker type II, III, IV, AO/OTA type 41-B2 and B3). Exclusion criteria consisted of skeletally immature patients <18 years of age, pure “split” fracture patterns (Schatzker type I, AO/OTA 41-B1), and bicondylar tibial plateau fractures (Schatzker V, AO/OTA 41-C types). All patients were consented for the use of balloon-guided osteoplasty, and understood the potential need for intraoperative conversion to an open procedure in case of technical problems with this new system. The inflatable bone tamp (KyphX® Inflatable Bone Tamp, Kyphon, Sunnyvale, CA) is approved by the U.S. Food and Drug Administration (FDA) for indications related to fracture reduction in the spine, tibia, hand, radius, and calcaneus (2004, #K041454).

All surgeries were performed by three fellowship-trained orthopaedic surgeons who are co-authors on this paper (CM: n = 9; PFS: n = 9; DJH: n = 2). The surgical technique has been previously described [16]. Specific technical aspects of the surgical procedure, including the choice of using a buttress plate versus percutaneous cannulated lag screws (Figure 1), as well as the adjunctive use of arthroscopy-guided visualization of the quality of joint surface reduction, were based on individual surgeon’s preference.

Intraoperative technical complications were stratified into “minor” and “major” events, using the following definitions:

All adverse events were prospectively entered into an institutional Quality Assurance (QA) database, disclosed to the affected patients per institutional policy [22], and formally peer-reviewed in a standardized fashion at the weekly Departmental QA conference [22]. This study was approved by the Colorado Multiple Institutional Review Board (COMIRB).

Between October 1, 2010, and December 1, 2012, a balloon-guided reduction of depressed tibial plateau fractures using an inflatable bone tamp was applied in a first pilot series of 20 consecutive patients (9 women, 11 men) with a mean age of 42.8 years (range 20–79). Two additional patients were treated by inflation osteoplasty during this time-period but were lost to follow-up and therefore excluded from the study. The fracture classification consisted of Schatzker II (n = 8), Schatzker III (n = 11), and Schatzker IV (n = 1) type injuries. The demographic data of the 20 patients are shown in Table 1. A total of 13 patients (65%) sustained an intraoperative technical complication, of which three patients sustained multiple adverse events. Eight complications were graded as “minor events” based on the definition outlined in the methods section (40%). These minor events consisted of (a) the intraoperative burst of a balloon (Figure 2), leading to local leakage of the radiographic contrast dye (n = 6); (b) the accidental extrusion of calcium phosphate into the posterior soft tissues, which remained asymptomatic (n = 1; Figure 3); and (c) the intraoperative displacement of the posterior wall fragment of the tibial condyle (n = 1; arrow in Figure 4).

“Major events” which altered the course of surgery occurred in 5 patients (25%). These included (a) the intra-articular penetration of soluble calcium-phosphate, requiring a formal arthroscopic wash-out and debridement (n = 1; Figure 5), and (b) the failure to elevate the depressed articular fragment by inflation osteoplasty (Figure 4), which required the conversion to an open procedure using a standard bone tamp (Figure 6) and structured grafting for metaphyseal support (n = 4). The most extreme complication pattern attributed to the “non-reducible” group of adverse events consisted of a break-through of the balloon into the knee joint (Figure 6).

The stratification of all patterns of technical complications into “minor” and “major” adverse events is depicted in Figure 7.

This is the first report on the surgical complications related to the emerging technique of balloon-guided osteoplasty for reduction of depressed tibial plateau fractures. Strikingly, we found a complication rate of 65% in our initial series of 20 cases. Most of these complications are fortunately benign and can be adequately managed as “no harm” events by specific bailout strategies, as discussed below. The indications for inflation-guided osteoplasty should be strict. Time since injury, fracture type and comminution around the depressed fragment are aspects that must be considered as part of the surgical decision-making. In our anecdotal experience, we strongly feel that the 2 week mark sets a threshold after which it becomes increasingly difficult to reduce a depressed articular fragment, particularly in young patients. This time-limit is certainly variable and depending on patient age, individual fracture pattern, and energy of the traumatic impact which may lead to impacted and incarcerated articular fragments.

In this article, we present a first pilot series of 20 consecutive patients treated by balloon-guided inflation osteoplasty for depressed tibial plateau fractures. Strikingly, the rate of technical intraoperative complications associated to the use of this novel technology was as high as 65%, implying a steep learning curve. None of the complications reported in this study led to any patient harm or adverse outcome. Patients must be counseled in detail about all risks and potential benefits of this new technology, including the high risk of technical intraoperative complications, and the option of a traditional surgical technique must be offered by the surgeon as part of the shared decision-making process.