A Locked Intraosseous Nail for Transverse Patellar Fractures: A Biomechanical Comparison with Tension Band Wiring Through Cannulated Screws

Anterior variable-angle locked plating of complex patella fractures - Does the type of polar screw matter?

BACKGROUND

Treatment of complex patella fractures represents a challenging clinical problem. Whereas controversy exists regarding the most appropriate fixation method, anterior plating is an emerging treatment option. A novel design of anterior variable-angle locking plates features radiating legs with integrated screw holes aiming at capturing fragments of the distal comminuted zone via either a locking or a cortical polar screw. The aim of this study was to compare the biomechanical performance of the novel anterior variable-angle locking plates used for fixation of complex patella fractures with either a locking or a cortical polar screw.

METHODS

Complex five-part AO/OTA 34-C3 patella fractures mimicking comminution around the distal pole were simulated in twelve human cadaveric knees. Specimens were randomized to two groups for treatment with an anterior variable-angle locking plate fixing the patella with either one locking or one cortical caudo-cranial bicortical polar screw. Biomechanical testing was performed over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive flexion within the range from 90° flexion to full extension. Interfragmentary movements were captured by motion tracking.

FINDINGS

No significant differences between the two fixation techniques were detected in terms of longitudinal and shear articular displacements, and relative rotations around the mediolateral axis measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, P ≥ 0.116.

INTERPRETATION

From a biomechanical perspective, anterior locked plating of complex patella fractures provides comparable fixation stability when using either a locking or a cortical polar screw.

Lateral rim variable angle locked plating versus tension band wiring of simple and complex patella fractures: a biomechanical study

INTRODUCTION

Treatment of both simple and complex patella fractures is a challenging clinical problem. Although tension band wiring has been the standard of care, it can be associated with high complication rates. The aim of this study was to investigate the biomechanical performance of recently developed lateral rim variable angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

MATERIALS AND METHODS

Sixteen pairs of human anatomical knees were used to simulate either two-part transverse simple AO/OTA 34-C1 or five-part complex AO/OTA 34-C3 patella fractures by means of osteotomies, with each fracture model created in eight pairs. The complex fracture pattern was characterized by a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral, and an inferior (central distal) fragment mimicking comminution around the distal patellar pole. The specimens with simple fractures were pairwise assigned for fixation with either tension band wiring through two parallel cannulated screws or a lateral rim variable angle locking plate. The knees with complex fractures were pairwise treated with either tension band wiring through two parallel cannulated screws plus circumferential cerclage wiring or a lateral rim variable angle locking plate. Each specimen was tested over 5000 cycles by pulling on the quadriceps tendon, simulating active knee extension and passive knee flexion within the range of 90° flexion to full extension. Interfragmentary movements were captured via motion tracking.

RESULTS

For both fracture types, the articular displacements measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following the lateral rim variable angle locked plating compared with tension band wiring, p ≤ 0.01.

CONCLUSIONS

From a biomechanical perspective, lateral rim variable angle locked plating of both simple and complex patella fractures provides superior construct stability versus tension band wiring under dynamic loading.

[Anterior plate osteosynthesis for multifragmentary patella fracture with additive stabilization of the distal pole using suture cerclage]

OPERATION GOAL

The aims of the surgical treatment are the anatomical reduction of the articular surface and stabilization of a multifragmentary patella fracture with a distal pole fragment using plate osteosynthesis and additive suture tape cerclage to secure the distal fragment.

INDICATION

Demonstration of the surgical procedure for a multifragmentary patella fracture in the knee joint of a male cadaver.

SURGICAL TECHNIQUE

Start with a median prepatellar skin incision and splitting of the bursa and surrounding fascia. Lateral arthrotomy with proximal and distal extension for complete eversion and articular exposure of the multifragmentary fracture. The fracture is then reduced from the articular side using temporary K‑wire fixation and reduction clamps, followed by screw osteosynthesis of the large fragments (e.g., distal and proximal poles). After selection of the plate it is fixed with locking screws. In addition, a suture cerclage according to Krakow and/or McLaughlin is applied distally and transosseously through the tibial tuberosity and proximally through the quadriceps tendon. The knotting of the McLaughlin suture cerclage should be done in 90° flexion of the knee joint.

POSTOPERATIVE TREATMENT

Functional postoperative treatment with hard shell orthesis with movement limitation (30°, 60° and 90° for 2 weeks each) and partial weight bearing of 15-20 kg for 6 weeks is recommended. Full weight-bearing is only allowed in full extension.

EVIDENCE

Plate osteosynthesis is biomechanically superior in comparison to the widely used tension band osteosynthesis. In multifragmentary fractures, additional augmentation with a suture tape cerclage seems to be appropriate. Due to the lack of study results there is currently no clinical evidence for this.

Anterior variable-angle locked plating versus tension band wiring of simple and complex patella fractures - a biomechanical investigation

BACKGROUND

The aim of this study was to investigate the biomechanical performance of novel anterior variable-angle locking plates versus tension band wiring used for fixation of simple and complex patella fractures.

METHODS

Sixteen pairs of human cadaveric knees were used to simulate two-part simple transverse AO/OTA 34-C1 and five-part complex AO/OTA 34-C3 patella fractures. The complex fracture pattern was characterized with a medial and a lateral proximal fragment, together with an inferomedial, an inferolateral and an inferior fragment mimicking comminution around the distal patella pole. Eight pairs with simple fractures were split for fixation via either tension band wiring (TBW) through two parallel cannulated screws or anterior variable-angle locked plating, whereas other eight pairs with complex fractures were split for either TBW through two parallel cannulated screws plus circumferential cerclage wiring, or anterior variable-angle locked plating using a cortical caudo-cranial polar screw. Each specimen was tested over 5000 cycles with a range of motion from 90° flexion to full extension by pulling on the quadriceps tendon. Interfragmentary movements were captured by motion tracking.

RESULTS

For both fracture types, the longitudinal and shear articular displacements, measured between the proximal and distal fragments at the central patella aspect between 1000 and 5000 cycles, together with the relative rotations of these fragments around the mediolateral axis were all significantly smaller following anterior variable-angle locked plating versus TBW, p ≤ 0.01.

CONCLUSIONS

From a biomechanical perspective, anterior locked plating of both simple and complex patella fractures resulted in less interfragmentary displacement under extended cyclic loading.

The effect of Ding's screws and tension band wiring for treatment of inferior pole patellar fractures

OBJECTIVES

We developed a cannulated screw with holes in the tail, named the Ding's screw. The objective of this study was to evaluate the clinical effect of Ding's screw in the treatment of inferior pole patellar fracture.

METHODS

From March 2017 to October 2021, 68 patients with inferior pole patellar fracture in our department were retrospectively reviewed. According to different treatment methods, they were divided into Ding's screw and tension band wiring group (DSTBW) and cannulated screws and tension band wiring group (CSTBW). Radiological and clinical outcomes were evaluated and compared.

RESULTS

There were 33 cases in DSTBW group and 35 cases in CSTBW group. The mean follow-up duration was 14.5 ± 2.6 months in the DSTBW group and 15.0 ± 2.3 months in the CSTBW group. No significant differences in age, sex, operative side or time to surgery were present between the two groups. Skin breakdown and infection were not significantly different among the groups (P > 0.05). At the last follow-up, the average Bostman score of the DSTBW group was 28.5 ± 1.3(excellent) and that of the CSTBW group was 27.8 ± 1.6(good), with statistical significance (P = 0.045). The average Lysholm score of the DSTBW group was 94.1 ± 3.4 (good), and that of the CSTBW group was 90.1 ± 4.4 (good), and the difference was statistically significant (P < 0.001). The average knee joint ROM of the DSTBW group was 135.6 ± 6.8˚, and that of the CSTBW group was 130.1 ± 6.7˚, and the difference between the two groups was statistically significant (P = 0.001).

CONCLUSIONS

DSTBW is an effective method for the treatment of inferior pole patellar fractures with stable fixation and good functional effect.

Transosseous suture versus suture anchor fixation for inferior pole fractures of the patella in osteoporotic bone: a biomechanical study

BACKGROUND

The surgical treatment of inferior patellar pole fractures can be a challenge, especially in geriatric patients, who are particularly frequently affected by osteoporosis. The objective of this biomechanical study was to compare the performance of suture anchor and transosseous suture fixation in fractures of the inferior patellar pole in context of bone mineral density.

METHODS

Twelve fresh-frozen human cadaveric knees received a transverse osteotomy, simulating an AO/OTA 34C1.3 inferior pole fracture of the patella. These fractures were fixated with either suture anchors (SA; Corkscrew® FT 4.5 mm) or transosseous suture (TS; #2 FiberWire®). Cyclic loading tests were performed by pulling the quadriceps tendon against gravity from 90° flexion to almost full extension (5°) for 1000 cycles. Motion and fracture gap displacement were tracked until failure occurred. Subsequently, loading to failure tests followed. Differences between groups were compared using unpaired t-tests, and correlations were calculated with Pearson's correlation coefficient.

RESULTS

The suture anchor group showed significantly fewer cycles to failure than the transosseous suture group (SA: 539.0 ± 465.6 cycles, TS: 1000 ± 0 cycles, P = 0.04). Bone mineral density correlated positively with cycles to failure in the suture anchor group (Pearson's r = 0.60, P = 0.02). No differences in fracture gap displacement could be proven after 100 cycles (SA: 4.1 ± 2.6 mm, TS: 6.5 ± 2.6 mm, P = 0.19); 500 cycles (SA: 6.4 ± 6.1 mm, TS: 9.6 ± 3.8 mm, P = 0.39); and 1000 cycles (SA: 4.0 ± 0.4 mm, TS: 11.0 ± 4.5 mm, P = 0.08). Furthermore, the mean destructive load to failure in the suture anchor group was also significantly lower than in the transosseous suture group (SA: 422.4 ± 212.2 N, TS: 825.7 ± 189.3 N, P = 0.04).

CONCLUSIONS

Suture anchors may be a viable alternative to transosseous suture in younger patients for clinical advantages, but in osteoporotic bone, the more stable osteosynthesis with transosseous suture continues to prove superior. Therefore, trauma surgeons might consider the use of transosseous suture in elderly patients, especially in those presenting with low bone mineral density values.

Biomechanical comparison of a novel tensioned cable construct versus tension band wiring for transverse patella fracture fixation

PURPOSE

Tension band wiring (TBW) is the most widely accepted method for patella fracture fixation. The purpose of our study was to compare the biomechanical efficacy of a novel cable construct to TBW for the fixation of transverse patella fractures. The tensioned cable construct was hypothesized to have less fracture gapping after cyclic flexion-extension loading and greater ultimate load to failure as compared to TBW.

METHODS

Transverse patellar osteotomies (AO/OTA 34C1.1) were performed on nine pairs of fresh-frozen human cadaveric whole legs (mean age 82.2 years, range 71-101). Treatment with TBW or tensioned cable construct was randomized within each specimen pair. Fracture site displacement was measured after 5000 flexion-extension cycles from 0° to 90° at 0.5 Hz. In load to failure testing, the knee was fixed at 45° of flexion and the quadriceps tendon was pulled proximally at 0.5 mm/sec until patella fixation failure. Comparisons were made using paired t-tests with alpha values of 0.05.

RESULTS

Eight paired specimens completed the cyclic loading. The tensioned cable construct had significantly less fracture gapping than TBW (2.9 vs 10.9 mm; p = 0.020). Seven paired limbs underwent load to failure testing, which revealed no significant difference between the tensioned cable construct and TBW (1551.6 N vs 1664.0 N; p = 0.26).

CONCLUSION

In this study of transverse patella fracture fixation, a tensioned cable construct demonstrated significantly less fracture gapping compared to TBW in response to cyclic loading with no significant difference in load at failure.

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

This study aims to compare the clinical outcomes of the nickel-titanium arched shape-memory alloy connector (hereafter referred to as the ASC) and tension band fixation for the treatment of transverse patellar fractures. We retrospectively analyzed a total of 257 patients with transverse patellar fractures who were treated at our emergency orthopaedics department from March 2010 to March 2017. Either an ASC or the Kirschner wire (K-wire) tension band had been used to treat these fractures according to surgeons' experience and preference. We compared operative details, postoperative recovery, and postoperative knee function at 6 months. In terms of surgical duration, blood loss, incision length, length of hospital stay, and postoperative complications, patients in the ASC group showed significantly better results than patients in the K-wire group (p < 0.05). There were no significant differences between the two groups in terms of fracture healing time, knee mobility, and the Boström score at the postoperative 6-month evaluation (p > 0.05). Though, there were similar functional outcomes between two groups whose transverse patellar fractures were different methods, we found that the ASC method was a more reliable, more minimally invasive, and safer treatment option than the tension band wiring method using K-wires, resulting in less tissue damage, shorter surgical duration, shorter length of hospital stay, and fewer complications.

Supplemental cerclage wiring in angle stable plate fixation of distal tibial spiral fractures enables immediate post-operative full weight-bearing: a biomechanical analysis

Purpose

Distal tibial fractures generally require post-operative weight-bearing restrictions. Especially geriatric patients are unable to follow these recommendations. To increase post-operative implant stability and enable early weight-bearing, augmentation of the primary osteosynthesis by cerclage is desirable. The purpose of this study was to identify the stabilizing effects of a supplemental cable cerclage following plate fixation of distal tibial spiral fractures compared to solitary plate osteosynthesis.

Methods

In eight synthetic tibiae, a reproducible spiral fracture (AO/OTA 42-A1.1c) was stabilized by angle stable plate fixation. Each specimen was statically loaded under combined axial and torsional loads to simulate partial (200 N, 2 Nm) and full (750 N, 7 Nm) weight-bearing. Tests were repeated with supplemental cable cerclage looped around the fracture zone. In a subsequent stepwise increased dynamic load scenario, construct stiffness and interfragmentary movements were analyzed.

Results

With supplemental cable cerclage, construct stiffness almost tripled compared to solitary plate osteosynthesis (2882 ± 739 N/mm vs. 983 ± 355 N/mm; p < 0.001). Under full weight-bearing static loads, a supplemental cerclage revealed reduced axial (− 55%; p = 0.001) and shear movement (− 83%; p < 0.001), and also lowered shear movement (− 42%; p = 0.001) compared to a solitary plate under partial weight-bearing. Under dynamic loads supplemental cerclage significantly reduced axial (p = 0.005) as well as shear movements (p < 0.001).

Conclusion

Supplemental cable cerclage significantly increases fixation stiffness and reduces shear movement in distal tibial spiral fractures. This stabilizing effect enables from a biomechanical point of view immediate mobilization without any weight-bearing restrictions, which may improve the quality of care of orthopedic patients and may trigger a change towards early weight-bearing regimes, especially geriatric patients would benefit from.

Comparison of the Therapeutic Effects of Tension Band with Cannulated Screw and Tension Band with Kirschner Wire on Patella Fracture

Background

Patella fracture accounts for 1% of bone injury, of which anatomical reduction is of great significance to the recovery. Tension band with cannulated screw and Kirschner wire is commonly used methods for the treatment of displaced patella fracture. However, there is still some controversy on the clinical efficacy of the two treatment methods.

Objective

This study aimed at comparing the therapeutic effects of the cannulated screw and Kirschner wire tension bands on patella fracture and at providing more data basis for clinical selection of treatment methods for patella fracture.

Methods

Altogether, 146 patients with displaced patella fracture admitted to our hospital from March 2016 to February 2018 were selected and divided into two groups according to the different treatment methods. Among them, 71 patients received tension band with a cannulated screw (TBWCS group) and 75 patients received tension band with Kirschner wire (TBWKW group). Two groups of patients were compared in terms of surgical treatment effect after one year of treatment, complications within six months after the operation and operation-related indexes. The pain visual analogue scale (VAS) score, knee flexion degree, Lysholm score, and Bostman score were recorded at 1, 3, 6, and 12 months after operation, and the activity of daily living scale (ADL) score was evaluated at the last follow-up.

Results

During the operation of patella fracture patients, the intraoperative blood loss, hospitalization time, and knee flexion loss of patients in TBWCS group were less than those in the TBWKW group (P < 0.05), the starting time of postoperative functional exercise was earlier than that of patients in TBWKW group (P < 0.05), and the incidence rate of secondary operation was lower than that of patients in the TBWKW group (P < 0.05), but there was no statistical difference in the operation time, incision length, and postoperative fracture gap between the two groups. The results of curative effect analysis showed that the knee flexion, Lysholm score, and Bostman score of patients treated with tension band with cannulated screw were higher than those treated with Kirschner wire (P < 0.05), and VAS score was lower. Tension band with cannulated screw had a better curative effect on patella fracture (P < 0.05), lower complication rate (P < 0.05), and higher quality of life of patients (P < 0.05).

Conclusion

Tension band with cannulated screw has a good curative effect on patella fracture, low incidence of complications, early start of postoperative functional exercise, and high quality of life.

Fracture Patterns and Comminution Zones in OTA/AO 34C Type Patellar Fractures

OBJECTIVES

To characterize the fracture patterns and comminution zones for complete articular (OTA/AO 34C type) patellar fractures, using a computed tomography mapping technique.

METHODS

Eighty-three OTA/AO 34C type patellar fractures were included. Images of patellar fractures were superimposed on a coronal template of the patella, created from a healthy right knee, to identify fracture patterns and comminution zones.

RESULTS

Our analysis was based on 83 computed tomography images of patellar fractures, contributed by 69 male and 14 female patients (mean age, 52 years; range, 18-79 years), and included 13 type C1, 26 type C2 and 44 type C3 fractures. A transverse fracture, including both the medial and lateral facets, was the most common fracture pattern, identified in 92.8% of cases. In the C1 and C2 types, the fracture line affecting the medial and lateral joint surface was either transverse or oblique. In the C3 type, the transverse and vertical fracture line of the medial articular surface extended to the inferior pole of the patella, with transverse and oblique fractures lines on the lateral joint surface. In addition, a concentration of the fracture lines around the vertical ridge was observed.

CONCLUSIONS

The patterns of fracture lines and comminution zones OTA/AO 34C type fractures were repeatable on the constructed maps. A transverse fracture line on the inferior pole which was observed in the C2 and C3 type fractures may be used for the modification of current classification systems to direct treatment.

Miniplate Augmented Tension-Band Wiring for Comminuted Patella Fractures

The aim of this study was to introduce various applications of miniplate augmented tension-band wiring (TBW) for comminuted patella fractures and to evaluate the clinical outcomes. Comminuted articular patella fractures were managed with anterior cortical miniplate fixation with a TBW technique from January 2014 to January 2016. The primary end point was radiographic union. Secondary end points were complications related to the procedure. Functional outcomes including range of motion were also evaluated. Thirty patients were followed up for a mean of 20 months (range, 12-28) postoperatively. The primary union rate was 96% (29 of 30 patients). Mean time to union was 3.2 months. One patient required additional surgery because of acute postoperative infection. Twenty-five patients recovered a full range of motion relative to the contralateral limb. The mean Bostman score at the last follow-up was 28.6 points (range, 26-30). In conclusion, miniplate augmented TBW is a versatile and useful technique for comminuted patella fracture fixation.