Treating patella fractures with a fixed-angle patella plate—A prospective observational study

doi:10.1016/j.injury.2016.06.018

Injury

Volume 47, Issue 8, August 2016, Pages 1737-1743

https://doi.org/10.1016/j.injury.2016.06.018 Get rights and content

Abstract

Introduction

Anterior tension wiring using Kirschner wires (K-wires) is still considered the standard treatment for patella fractures, despite its high complication rate. The objective of this prospective clinical study was to evaluate intra- and perioperative complications as well as the clinical outcome of patients with patella fracture treated with a new developed bilateral, polyaxial, fixed-angle 2.7 mm patella plate.

Patients and methods

Between 2011 and 2014 all patients with a patella fracture were included in this prospective study and treated with a fixed-angle patella plate. Avulsion fractures of the inferior or superior pole of the patella were excluded. All fractures were classified according to the AO/OTA fracture classification. During a twelve-month follow up period all intra- and postoperative complications were recorded as well as the time until fracture healing. One year postoperatively the Lysholm Score, the pre- and postoperative Tegner Score, the Hospital for Special Surgery Knee Score (HSS), the Turba Score, the Oxford Knee Score, the Knee injury and Osteoarthritis Outcome Score (KOOS), the Bostman Score and the Iowa Knee Score were surveyed. Altogether, 20 patella fractures in 19 patients were included in this prospective study. The most frequent type of fracture, n = 10, was a simple transverse patella fracture (C1), followed by 7 comminuted patella fractures (C3) and 3 T-shaped patella fractures (C2).

Results

During the 12-month follow up period two patients treated with the patella plate had a complication. In one patient a superficial wound infection occurred, which was treated successfully with hardware removal and in one patient a fracture dislocation due to an implant failure occurred. X-rays demonstrated complete bony healing in all fractures on average 3.2 months postoperatively. All knee scores showed good to excellent clinical results one year postoperatively.

Conclusion

The results of this first clinical study indicate that the fixed-angle patella plate is an effective and safe treatment option for patella fractures with a short operative learning curve. The treatment of communited patella fractures (C3) with a fixed-angle patella plate should be well-considered to avoid distending the indication and biomechanical properties.

Introduction

With a prevalence rate of just 1% patella fractures are not among the most common skeletal injuries in humans [1]. Approximately one-third of all patella fractures require a surgical intervention, either when the fracture gap exceeds 2–3 mm or in case of joint incongruence [1]. Modified anterior tension wiring is still the most widely used and advocated surgical treatment option for patella fractures [2], [3]. However, despite several technical modifications of anterior tension wiring, typical complications, such as failure of fixation with early fracture dislocation occur in up to 22–30% of all cases [4], [5]. Furthermore, migration of K-wires, postoperative pain and high rates of revision surgery can be observed with this technique leading to unsatisfactory long-term results in clinical studies [3], [6], [7]. Postoperative pain due to skin irritation caused by the K-wires is also a common problem when using modified anterior tension wiring [8]. Thus, revision surgery with K-wire removal becomes necessary in up to 65% of all cases [8].

Encouraged by the improved primary stability of fixed-angle plates in fracture treatment, a fixed-angle patella plate was developed by the author of this manuscript (Fig. 1). Biomechanical studies showed a superior and significant higher stability of this bilateral fixed-angle patella plate compared to the two currently most common used surgical techniques for patella fractures: modified anterior tension wiring with K-wires and cannulated lag screws with anterior tension wiring [9], [10].

Goal of this first prospective clinical study was to evaluate the safety, efficiency and outcome in patients with patella fractures treated with this novel fixed-angle patella plate. A special focus was set on intra- and postoperative complications and hardware failure.

Section snippets

Patients and methods

This study was approved by the local ethics board of our institution. All patients gave their oral and written consent and were given the option to discontinue participation at any time. Between 2011 and 2014 patients with a patella fracture and a fracture displacement or articular incongruity > 2–3 mm were included in this prospective study and treated with a fixed-angle stable patella plate (Koenigsee Implantate^®, Allendorf, Germany) at the authoŕs institution (Fig. 1, Fig. 2). Avulsion

Results

The duration of the surgical procedure was on average 74 min (range: 37–116 min) and no intraoperative complications could be observed.

During the 12-month follow up period, two patients treated with the patella plate had a complication. A 68-year-old woman developed a superficial wound infection, which healed immediately after removal of the patella plate, and one 71-year-old woman showed a secondary fracture dislocation with an intrarticular gap of more than 2 mm. Due to this dislocation,

Discussion

In 2012 Dy et al. [20] published a meta-analysis to evaluate the re-operation, non-union, and infection rate following open reduction and internal-fixation of patella fractures. Analyzing 24 studies with a total of 737 patella fractures treated with tension band wiring or other surgical techniques they found a re-operation rate of 33.6%. The authors conclude that although the non-union and infection rates of these techniques are fair, the re-operation rate of these techniques is substantially

Conclusions

The operative treatment of patella fractures is still a challenge even for an experienced surgeon. The results of our study show that the fixed-angle patella plate is a good and safe option treating different kind of patella fractures with a short learning curve and promising first results. However, the treatment of communited patella fractures (C3) with a fixed-angle patella plate should be well considered to avoid distending the indication and biomechanical properties.

Conflict of interest

The first author receive as developer of the implant a passive income from turnover sharing as well as reimbursements for lectures.

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Citation Excerpt :
In light of some of these results a number of investigators have developed fixation strategies to avoid the need for implant removal and to improve biomechanical resiliency, though clinical studies have lagged behind laboratory testing. Wild et al., in a prospective clinical study of their newly developed 2.7 mm fixed angle locking plate, have shown a failure rate of 5% and an implant removal rate due to symptomatic implants of 20% [30]. Our technique uses a relatively inexpensive construct with some of the most readily available plates and screws.
The purpose of this study was to compare the biomechanical attributes of patella fracture fixation with either anterior plating utilizing two parallel, longitudinal 2.0 mm plates technique versus a cannulated screw tension band technique.
Five matched pairs (ten specimens) of fresh frozen cadavers were utilized. A transverse patella fracture (OTA 34C1.1) was fixed using either two 4.0 mm cannulated screw anterior tension band (CATB) or with two 2.0 mm stainless steel non-locking plates along the anterior cortex secured with 2.4 mm cortical screws traversing the fracture site. Specimens underwent 1000 cycles of simulated active knee range of motion before load to failure destructive testing.
During cyclic loading there were no failures in the plate fixation group, and 2 out of 5 specimens catastrophically failed in the CATB group (p = 0.22). Average fracture displacement at the end of fatigue testing was 0.96 mm in the plate fixation group and 2.72 mm in the CATB group (p = 0.18). The specimens that withstood cyclic testing underwent a destructive load. Mean load to failure for the plate fixation specimens was 1286 N, which was not significantly different from the CATB group mean of 1175 N (p = 0.48). The mechanism of failure in the plate fixation cohort was uniformly via a secondary vertical patella fracture around the plates in all five specimens. In the CATB group, the mechanism of failure was via wire elongation and backing out of the screws.
Patella fixation with anterior plating technique statistically performed equivalent to cannulated screw anterior tension band in ultimate load to failure strength and fatigue endurance under cyclical loading. No failures were observed cyclic simulated active range of motion in the anterior plate group. There was a trend towards improved fatigue endurance in the plate fixation group, however this did not reach statistical significance. We believe plate fixation technique represents a low-profile implant option for treatment of transverse patella fractures, which may allow for early active range of motion, and these data support biomechanical equivalency to standard of care.
Comminuted patellar fractures: The role of biplanar fixed angle plate constructs
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The challenge in cases of comminuted fractures is the lack of continuity on the articular surface of the patella. Low profile locking plates have been used to neutralize tension forces in case of comminuted patellar fractures [6,7]. However, we lack standardization with regard to the three-dimensional (3D) distribution of the screws within a plate.
Comminuted patellar fractures represent a challenging clinical problem. Their treatment aims to restore the integrity of the extensor mechanism and the congruity of patellofemoral joint. Controversy exists regarding the ideal fixation method. Metallic constructs aiming to convert pulling forces on the anterior aspect of the patella into compression forces across the fracture site are the standard of care. More recently, low profile plates have been described in the management of comminuted patellar fractures. The aims of this study were to (1) develop a novel unstable patellar fracture model and (2) compare biomechanically three different constructs for fixation of comminuted patellar fractures. We hypothesized that an orthogonal biplanar disposition of the screws within an anteriorly placed locking plate provides the best biomechanical performance in the management of comminuted fractures.
Six-part complex AO 34–C3 patellar fractures were simulated in 18 human cadaveric knees by means of osteotomies including comminution around the distal patellar pole. The specimens were randomly assigned to 3 fixation techniques (n = 6) for either anterior mesh plating, antero-lateral mesh plating, or tension band wiring (TBW). Biomechanical testing was performed over 5000 cycles in active extension and passive flexion, followed by ultimate destructive quasi-static testing. Interfragmentary movements were captured by means of optical motion tracking.
Displacement between the proximal and distal medial patellar fragments was lower after anterior plating compared to both antero-lateral plating (P = 0.084) and TBW (P < 0.001). Moreover, displacement between the proximal and distal lateral fragments was significantly lower after anterior plating compared to both other techniques (P ≤ 0.032). In addition, it was significantly lower for antero-lateral plating versus TBW (P < 0.001). Rotation around the medio-lateral axis between the proximal and distal medial fragments was significantly lower after anterior plating compared to TBW (P = 0.017).
Anterior mesh plating with biplanar placement of locking screws provides superior stability for fixation of comminuted patellar fractures when compared to both antero-lateral mesh plating and TBW. The latter is associated with considerably inferior performance.
Hook plating in patella fractures
2019, Injury
Citation Excerpt :
The current study revealed that plating could achieve bony union without secondary reduction loss or mechanical failures, and clinically satisfactory outcomes were obtained. Previous biomechanical studies [7–9] demonstrated that plating in patella fractures provides superior strength compared to TBW, and several plate products for the patella have been introduced and are in use [10–15]. Several authors reported satisfactory outcomes in treating simple and comminuted fractures using the locking patella plate [13–16], comminuted fracture using mesh plate [10,12,13], and inferior pole fracture using basket plate and rim plate augmentation [11,17].
Tension band wiring is considered the standard treatment for patella fractures. However, it is limited for fractures with marginal involvement, comminution, and osteoporotic bone. Our experience indicates that these limitations can be overcome with the hook plate. We evaluated the radiographic and clinical outcomes in patients with patella fracture treated with hook plating.
We enrolled 30 patients who underwent hook plating for patella fracture at two institutions between 2013 and 2017. Fracture classification and surgical options were reviewed. Postoperative fracture gap and time to union as radiographic measurements, and complications, range of motion, and functional outcome with the Lysholm score as clinical outcomes, were evaluated retrospectively.
Nine fractures were AO/OTA 34A1, three B1, one B2, two C1, nine C2, and six C3. All were closed fractures. There were 3 cases of revision, 4 with lateral or medial marginal fracture, 9 with isolated inferior pole fracture, and 14 with comminuted fracture. The average postoperative fracture gap was 0.4 (range, 0–2.0) mm, and bone union was achieved without additional intervention. The average time to union was 11.6 (range, 7–24) weeks. There were no complications, and no extension lag except in one case (10°). The average flexion was 138.5° (range, 110–145°). For functional outcomes, the average Lysholm score was 89.5 (range, 74–95), with 13 excellent, 14 good, 3 fair, and no poor cases.
This study suggests that hook plating can result in good bone union and restored knee function in marginal or comminuted fractures of the patella.
Contourable craniofacial mesh plate osteosynthesis of patellar fractures: A new, low-profile fixation technique
2019, Journal of Clinical Orthopaedics and Trauma
Citation Excerpt :
Achieving biomechanical stability during patellar fracture fixation is imperative as the stability of fixation is tested thousands of times as the knee is put through numerous cycles of flexion and extension during the recovery period. While tension band wiring—with or without K-wire, screw, or cerclage wire augmentation—is the most widely accepted form of treatment for patellar fractures, plate osteosynthesis is gaining popularity for certain fracture patterns.5–7 We present below a novel form of patellar fracture fixation using MatrixNEURO Contourable Mesh plates (Synthes®).
Patellar fractures are challenging orthopaedic injuries that can be difficult to treat due to the complexity of fracture patterns, the high stresses at the patellofemoral joint, and subcutaneous location of the patella. Hardware prominence and need for hardware removal are two of the most common complications after surgical fixation of patellar fractures. There is an ever present need for low profile fixation constructs that are also biomechanically stable.
We present an alternative technique of patella fixation with a low profile titanium mesh plate typically used in craniofacial skeletal trauma. Four patients at our institution underwent mesh plate fixation of patella fractures.
All four patients had union without any post-operative complications. All four patients regained preoperative range of motion without residual pain or disability.
Mesh plate fixation of patellar fractures is an alternative to standard tension band technique, especially in comminuted fractures. The craniofacial mesh plate is very low profile, provides stable fixation that allows for early range of motion, and has the potential to reduce post-operative complications like hardware removal.
Clinical observation of C3-type patellar fractures treated by operation methods with or without a turned-over patella
2019, Injury
To evaluate the clinical efficacy of operation methods with or without a turned-over patella for treatment of C3-type patellar fractures.
A total of 68 patients with C3-type patellar fractures undergoing open reduction and internal fixation were retrospectively selected and treated with a turned-over patella surgery (turned-over patella group, n = 30) or conventional therapy without turning over the patella (conventional group, n = 38). The intraoperative and postoperative indicators of the two groups were assessed and comparatively analyzed.
The bedridden time was significantly shorter in the turned-over patella group than in the conventional group (P = 0.002), while the range of motion (ROM) of knee joint was significantly higher in the turned-over patella group (P = 0.044). The Lysholm score was slightly higher in the turned-over patella group than in the conventional group, but the difference was not statistically significant (P = 0.055). No significant difference was observed between the two groups in terms of the operation time (P = 0.096), intraoperative blood loss (P = 0.543), time of weight bearing (P = 0.312), fracture healing time (P = 0.272), or complications (P = 1).
The turned-over patella operation method exhibited some superiority to conventional reduction-fixation approach for treatment of C3-type patellar fractures in terms of efficacy and safety by enlarging the ROM of the knee joint and promoting functional recovery.

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Treating patella fractures with a fixed-angle patella plate—A prospective observational study

Abstract

Introduction

Patients and methods

Results

Conclusion

Introduction

Section snippets

Patients and methods

Results

Discussion

Conclusions

Conflict of interest

Injury

Injury

Injury

Clin. Biomech. (Bristol Avon)

Osteoarthr Cartil

Injury

Injury

Injury

Fracture of the patella: a study of 422 patellar fractures

Acta Orthop Scand Suppl

Open reduction internal fixation of displaced transverse patella fractures with figure-eight wiring through parallel cannulated compression screws

J Orthop Trauma

Early complications in the operative treatment of patella fractures

J Orthop Trauma

The late prognosis after fracture of the patella

Acta Orthop Scand

Fractures of the patella treated by operation

Arch Orthop Trauma Surg

Open fractures of the patella: long-term functional outcome

J Trauma

Fracture and dislocation compendium. Orthopaedic Trauma Association Committee for Coding and Classification

J Orthop Trauma

Evaluation of knee ligament surgery results with special emphasis on use of a scoring scale

Am J Sports Med

Rating systems in the evaluation of knee ligament injuries

Clin Orthop Relat Res