Then, we placed Kirschner wires (K-wires) across the fracture in an antegrade fashion, anterior to the trochlea and notch, using an accessory medial peripatellar starting point percutaneously, under direct visualization to avoid iatrogenic chondral injury. The tibial spine fragment was temporarily maintained in a reduced position with an arthroscopic probe and pinned in place with two 0.062-in K-wires. The fracture was stabilized with 8 resorbable 1.6-mm poly-L-lactic/polyglycolic acid (PLLA/PGA) nails, in varying lengths from 18 mm to 22 mm. Excellent fixation was obtained, and range of motion was tested from 0º to 80º, without movement of the fracture site (Figure 3E). Fluoroscopy with multi-axial views verified adequate fixation and reduction. Further, we examined and noted a taut ACL after fixation. The patient was placed in a long leg cast for 3 weeks at 30º, based upon intraoperative determination of the position of least tension on the fracture fragment.
At 3-week follow-up, the patient was progressing well and transitioned from a long leg cast to a hinged knee brace, to allow for early range of motion. Radiographs showed appropriate alignment of the tibial spine fracture with no significant loss of fixation (Figures 4A, 4B). Physical therapy was initiated between 0º and 30º, and flexion was progressively increased over the course of the first 3 weeks. Active and active-assist, closed-chain activities were maintained. Seven weeks postoperatively, the patient displayed continued clinical progression. Radiographs showed interval healing with slight lucency over the anterolateral aspect of the fracture fragment, likely related to the early resorptive process of healing. Physical examination showed movement between 0º and 120º, stable Lachman test, and stable anterior drawer. Crutches were discontinued and hinged knee brace was converted to an ACL brace. By the 11th week, motion had increased to 140º, and radiographs continued to show acceptable alignment and healing (Figures 5A, 5B). The patient was released to return to play as tolerated; however, an ACL brace was recommended during his initial return to provide additional support.
Discussion
In this report, we present an approach for arthroscopic reduction of a malunited tibial spine fracture using resorbable PLLA/PGA nails. The number of polyglycolic nails employed is individualized per case, dependent on the surface area and the quality of the bone within the fractured fragment. Preoperative templating allows for measurements from the fractured fragment to the level of the proximal tibial physis. Based on these measurements, nails are chosen to maximize fixation length and avoid the physis. Despite studies that have examined the effect of transphyseal K-wire pinning or drilling on subsequent growth, there is no consensus about optimal technique. Experiments in animal models indicate that drill injuries destroying less than 8% to 9% of the physis do not impact total bone growth.12,13 Further, temporary crossing of the physeal plate for internal fixation of dislocated joint injuries has not been shown to result in bone bridging or growth disturbance.14,15
Each nail is 1.6 mm in diameter, leaving a small footprint. The nails are used judiciously to provide effective stabilization of the fragment and to maintain a cost-conscious approach. An accessory superomedial peripatellar portal allows an appropriate angle for nail placement. This portal allows access to all regions of the fractured fragment, while an anteromedial and anterolateral portal are used as working and camera portals, respectively. Nails are placed to provide an axis perpendicular to the fracture line to allow appropriate compression. By virtue of the shape of the typical fragment in a tibial spine fracture, the nails vary in insertion angle.
The occurrence of anterior tibial spine fractures is rare, and while several techniques have been described to repair this fracture, there remains a great deal of uncertainty regarding the best course of treatment. A review of the literature finds arthroscopic and open approaches, as well as techniques employing K-wire fixation, metal screw fixation, staple fixation, absorbable fixation, and fixation with sutures passed through the tibial tunnel.16-18
Avulsion fractures of the tibial eminence were treated with open fixation until McLennan8 first reported the benefits of reduction with an arthroscope. Open reduction and internal fixation provide the benefit of direct visualization,9 while arthroscopic reduction offers decreased morbidity and an accelerated recovery of knee functions,8 despite the fact that a higher rate of range-of-motion deficits were seen in patients treated arthroscopically.19 We feel that with proper early rehabilitation to achieve range of motion, the risk of this can be minimal.
Various arthroscopic approaches that improve the accuracy of the reduction and decrease surgical invasiveness have been described. Suture and screw fixation are among the most common methods, and both have resulted in positive outcomes.20-24 Suture fixation of the tibial eminence is technically demanding but offers secure fixation without the need for follow-up hardware removal. Screw fixation results in secure fixation; however, numerous hardware-related issues may necessitate removal. Furthermore, in skeletally immature patients, screw fixation may disturb the growth plate if it crosses an open physis.9