Comparison of the outcomes of cannulated screws vs. modified tension band wiring fixation techniques in the management of mildly displaced patellar fractures

Abstract

BackgroundK wire fixation with tension band wiring has conventionally been used for the open reduction and internal fixation of the patella. However, it suffers from distinct disadvantages such as implant irritation, need for open reduction, incidence of palpable implants, and need for subsequent implant removal. A smaller incision with percutaneous fixation may be an alternative to this established conventional technique. Thus, the purpose of this trial was to compare the treatment outcomes of patients with mildly displaced patellar fractures treated with closed reduction and percutaneous cannulated screw fixation (CRCF) as compared to open reduction and tension band wiring fixation (ORTF). Specifically, we aimed to determine whether cannulated screw fixation was associated with improved clinical outcomes at 12 months as measured using the Lysholm score, pain scores, degree of flexion, range of motion, time to radiographic union, radiographic outcomes, and complication rates.MethodsSixty-three patients with transverse patellar fractures displaced less than 8 mm were included in this prospective, randomized, controlled trial, with 52 patients in the final data analysis. Thirty-two patients were operatively treated by CRCF with either two or three cannulated screws. Thirty-one patients were operatively treated by conventional ORTF using the modified tension band technique. At postoperative intervals of 3, 6, and 12 months, knee function was evaluated using the Lysholm score, pain was assessed using the visual analog scale (VAS) score, and active knee extensions and flexion were measured in degrees by goniometry.ResultsThe CRCF group had average Lysholm scores of 84.4 ± 5.8, 86.7 ± 6.4, and 93.2 ± 5.3 after 3, 6, and 12 months, respectively, which were significantly greater than those of the ORTF group (79.0 ± 5.3, p = 0.001; 81.5 ± 4.6, p = 0.002; and 89.8 ± 6.2, p = 0.039, respectively). Lower pain and squatting scores were the main reasons for the poorer Lysholm scores in the ORTF group. The VAS scores showed that the CRCF group had lower pain scores and better flexion and total range of motion (ROM) compared with the ORTF group after 3 and 6 months, although both groups had similar outcomes after 12 months. The mean fracture healing time of 2.65 months was similar in the CRCF groups (2.77 months; p = 0.440). Complication rates were 3/26 (11.5 %) in the CRCF group and 14/26 (53.4 %) in the ORTF group. Two patients in the CRCF group and eight patients in the ORTF group experienced skin irritation. In addition, two (7.7 %) patients in the CRCF group and 11 (42.3 %) patients in the ORTF group required implant removal because of symptoms due to the presence of the implants.ConclusionSurgical treatment of mild displaced (less than 8 mm) transverse patellar fractures by the CRCF technique provides satisfactory clinical results and excellent knee function, with little pain and a low incidence of complications at early follow-up (up to 6 months). These results suggest that the CRCF technique may be a superior alternativ...

Biomechanical evaluation of simulated feline patellar fracture repairs

“…The commonest fracture configuration in humans is transverse, usually due to trauma, although stress fractures are also reported (4). In human orthopaedics, a large number of fixation methods for patellar fractures have been described (7)(8)(9)(10)(11)(12)(13)(14).…”

Comparison of the Kirschner Wire Tension Band with a Novel Nickel–Titanium Arched Shape–Memory Alloy Connector in Transverse Patellar Fractures: A Retrospective Study

“…In addition, our results showed that 21.4% of K-wire group patients experienced protrusion of fixation material under the skin. The ends of K-wires stimulated the soft tissue and caused pain, thus affecting performance in early functional exercise of the knee, 26 which was not beneficial to knee joint function. Pain caused by the K-wires can lead to hardware removal, rates of which have been reported to range from 37 to 55% for transverse patellar fractures 27 ; the pain is the main reason for such removal.…”

A precise navigation device for fixation of patella fractures with modified K-wire tension band: design and application

“…Although there are new techniques such as cannulated screw tension band [11,12] system [13] and patella plate [14], the MTBW is still the most widely accepted surgical method for the treatment of patellar transverse fracture [7]. The MTBW technique is easy to operate on and economical to reduce the burden on patients, and the key of MTBW technique is to keep two k-wires parallel [8,15].…”