Interventions for treating fractures of the patella in adults

Tension band high-strength suture combined with absorbable cannulated screws for treating transverse patellar fractures: finite element analysis and clinical study

Objective: Few reports exist on the treatment of transverse patellar fractures (TPFs) using absorbable cannulated screws and high-strength sutures, and most screws and sutures lack good biomechanics and clinical trials. Therefore, this study aimed to demonstrate the biomechanical stability and clinical efficacy of tension-band high-strength sutures combined with absorbable cannulated screws (TBSAS) in treating TPFs (AO/OTA 34 C1). Methods: Finite element models of five internal fixation schemes were established: tension-band wire with K-wire (TBW), TBW with cerclage wire (TBWC), TBW with headless pressure screws (TBWHS), TBW with full-thread screws (TBWFS), and TBSAS. We comprehensively compared the biomechanical characteristics of the TBSAS treatment scheme during knee flexion and extension. Forty-one patients with TPFs in our hospital between January 2020 and August 2022 were retrospectively enrolled and divided into the TBSAS (n = 22) and TBWC (n = 19) groups. Clinical and follow-up outcomes, including operative time, visual analog scale (VAS) pain score, postoperative complications, Bostman score, and final knee range of motion, were compared between both groups. Results: Finite element analysis (FEA) showed that TBWHS and TBWFS achieved the minimum mean fracture interface relative displacement during knee flexion (45°, 0-500 N bending load) and full extension (0°, 0-500 N axial load). There was no significant difference between TBSAS (0.136 mm) and TBWC (0.146 mm) during knee flexion (500 N); however, TBSAS displacement was smaller (0.075 mm) during full extension (500 N). Furthermore, the stress results for the internal fixation and the patella were generally lower when using TBSAS. Retrospective clinical studies showed that the TBSAS group had a shorter operative time, lower VAS pain score at 1 and 2 months postoperatively, better Bostman knee function score at 3 and 9 months postoperatively, and better final knee joint motion than the TBWC group (all p < 0.05). There were five cases (26.3%) of internal fixation stimulation complications in the TBWC group. Conclusion: TBSAS demonstrated excellent safety and effectiveness in treating TPFs. It is sufficient to meet the needs of TPF fixation and early functional exercise and effectively reduces metal internal fixation-induced complications and secondary surgery-induced trauma.

High return to sports rates after operative treatment of patella fractures

BACKGROUND

Patella fractures are relatively rare fractures and only little is known about the postoperative return to sports after patella fractures.

METHODS

This retrospective study presents information on functional outcome after operative treatment of patella fractures as well as time until return to sports and patients' complaints after open-reduction internal-fixation (ORIF) of patella fractures.

RESULTS

Overall, 39 patients after ORIF of patella fractures were evaluated at our Level-I trauma center with a mean follow-up of 42 months. The mean time until return to sports was 7 ± 3.9 months. No significant difference was found for functional outcome with respect to body mass index (BMI) or age. Fracture consolidation was accomplished after a mean of 6.9 ± 2.9 months besides a relatively low complication rate of 5.1% (n = 2).

CONCLUSION

The results demonstrate a high return to sports rate of 90.3%. However, only 51.6% were able to perform sports on their pre-injury level or above. Trial Registration The study was retrospectively registered at DRKS (No: DRKS00031146).

Management of comminuted patellar fractures using suture reduction technique combined with the modified Kirschner-wire tension band

OBJECTIVES

Surgical management of comminuted patella fractures remains a major challenge for the surgeon. We developed a suture reduction (SR) technique to better preserve the comminuted patella. The study aimed to compare the suture reduction technique with conventional reduction (CR) technique in the management of comminuted patellar fractures using the modified Kirschner-wire (K-wire) tension band.

METHODS

From May 2016 to September 2020, a total of 75 patients with comminuted patellar fracture were reviewed retrospectively. Among these cases, 35 patients were in the suture reduction group with a mean age of 52 years, while 40 patients were in the conventional reduction group with a mean age of 53 years. All cases were closed fractures. Comminuted patellar fractures were classified as type 34-C3 according to the AO/OTA classification. Radiographs of the knee were obtained at routine follow-up to evaluate the reduction quality and fracture union. Clinical outcomes including range of motion (ROM), visual analog scale (VAS), Lysholm, and Böstman grading scales were measured at the last follow-up. Postoperative complications were also recorded.

RESULTS

The average time from injury to surgery was 5.4 days in suture reduction group and 3.7 days in conventional reduction group (p < 0.05). The surgical time of suture reduction group was less than that of conventional reduction group, but there was no significant difference (p = 0.110) regarding surgical time between the two groups. The average blood loss in suture reduction group was 42.9 ml, while the average blood loss in conventional reduction group was 69.3 ml (p < 0.001). There was no difference regarding fracture union, ROM and knee function score (Lysholm score and Böstman scale) between the two groups. The complication rates were 17.1% in suture reduction group and 12.5% in conventional reduction group respectively (p > 0.05).

CONCLUSIONS

In the treatment of comminuted patellar fractures with modified K-wire tension band, the use of suture reduction technique can shorten the surgical time, reduce the surgical trauma, and obtain satisfactory results. This new surgical technique may be particularly effective in management of comminuted patellar fractures when patellectomy would otherwise be considered.

[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 use of a 30-degree radiolucent triangle during surgery in distal avulsion fractures of the patella

BACKGROUND

Avoiding patella baja or alta after the Krackow suture technique for distal avulsion fractures of the patella can be challenging. We aim to introduce a simple and reproducible technique using a 30-degree radiolucent triangle involving the contralateral knee to ensure the correct positioning of the patella intraoperatively.

METHOD

The radiolucent triangle is positioned under the contralateral knee before operating the injured knee. A strict lateral view is obtained using fluoroscopy as a reference before a Krackow technique is performed on the avulsion fracture of the patella.

RESULTS

The triangle technique is straightforward and easily reproducible by surgeons of all levels. It allows the surgeon to correctly position the patella intraoperatively in avulsion fracture repair and modify tension on the patellar tendon.

CONCLUSION

This method avoids millimetric mispositioning of the operated patella, thus improving the management intraoperatively and could decrease postoperative complications.

A New Antirotation Strategy of K-Wire Tension Band Therapy for Patellar Fracture

Background

Patellar fracture is a common phenomenon observed in orthopedic clinics. Many methods have been shown to be effective in the fixation of patellar fracture. However, there are few studies on the antirotation effect of these methods. The purpose of this study is to present a new strategy of K-wire tension band therapy for patellar fracture and explore the antirotation effect of the modified tension band method on patellar fracture.

Methods

A retrospective clinical observation study was conducted on 75 patients with patellar fracture. Totally, 46 patients were enrolled to the traditional group, who received the traditional K-wire tension band therapy. The modified group included 29 patients on whom our new strategy was implemented. The operation time, intraoperative blood loss, and fracture healing time were collected to compare the two operations and the knee society score (KSS) scores after the operations, and complications were recorded and retrieved to indicate the effectiveness of the two treatments.

Results

The preoperative baseline data (gender, age, fracture types) of the two groups showed no significant statistical difference. Similarly, there was no significant difference in the operation time, intraoperative blood loss, and fracture healing time between the two groups. The KSS clinical scores 1 year after operation was 90 (84, 95) for the traditional group as compared with 99 (97, 100) for the modified group (p < 0.05). The KSS functional scores 1 year after operation in the two groups were 90 (65, 90) and 100 (90, 100) (p < 0.05). The incidences of complications due to the rotation of K-wires in the traditional group and the modified group were 76.1% (35 of 46) and 6.9% (2 of 29) with a significant statistical difference (p < 0.05).

Conclusion

This study shows that our modified tension band therapy is an effective strategy for antirotation in the treatment of patellar fracture and proves that it can achieve better clinical outcomes than the traditional K-wire tension band method. This new strategy may be a safe and effective clinical technique for the treatment of patellar fracture. However, more prospective randomized controlled trials with larger sample sizes are still needed to further prove its efficacy.