Complications following tension-band fixation of patellar fractures with cannulated screws compared with Kirschner wires

What Factors Are Associated With Patella Baja After Internal Fixation of Patellar Fractures?

BACKGROUND

Patellar fractures represent approximately 0.5% to 1.5% of all trauma-related fractures, and patella baja, or an abnormally low-lying patella, may be a result of treatment. This complication is underappreciated, and although patella baja may result in patient discomfort, stiffness, and later degenerative changes, the association between fracture type, operative treatment, and this complication is not well described.

QUESTIONS/PURPOSES

(1) What percentage of patients treated surgically for patellar fractures developed patella baja, and which fracture patterns were more likely to demonstrate postoperative patella baja? (2) What was the association between postoperative patella baja and functional outcomes as measured by ROM and Böstman score? (3) What complications were associated with the development of patella baja?

METHODS

Between January 2018 and January 2021, we treated 3244 patients for patellar fractures at the National Center for Orthopaedics in Shanghai, PR China. The average age of the patients was 53.4 ± 12.0 years, and the male-to-female ratio was 1:1.34. After accounting for exclusion and inclusion criteria, 11% (259 of 2370) of patients were lost to follow-up before 2 years, leaving 2111 patients for review in this retrospective study at a mean of 32 ± 9 months after injury. During this time, we generally recommended surgery for patellar fractures when the fracture demonstrated an articular surface step-off exceeding 2 mm or there was loss of knee extension function. According to the AO/OTA (Arbeitsgemeinschaft für Osteosynthesefragen/Orthopaedic Trauma Association) classification systems, the fractures were divided into eight subtypes: A1, B1, B2, C1.1, C1.2, C1.3, C2, and C3. All of these patients had CT scans and clinical data collected in our longitudinally maintained institutional database. Two independent observers classified the fractures based on the preoperative CT scan and recorded the Insall-Salvati index (ISI) on plain radiographs at the 2-year follow-up visit. An ISI of < 0.8 determined the presence of patella baja. Patient demographics, ROM, Böstman functional scores, complications, and implant removal rates were assessed. Binary logistic regression and linear regression models were employed to analyze risk factors for patella baja, associations, and treatment outcomes. Under the AO/OTA classification, the most common fracture patterns were C1.1 (30% [634 of 2111]) and C3 (25% [538 of 2111]).

RESULTS

Overall, 25% (527 of 2111) of patients had postoperative patella baja, and those with type A1 (OR 6.44 [95% confidence interval (CI) 4.57 to 9.10]), C1.3 (OR 4.96 [95% CI 3.68 to 7.10]), and C3 (OR 2.61 [95% CI 1.93 to 3.52]) fractures displayed a higher odds of developing patella baja. Patients with patella baja had poorer ROM in flexion than did patients without patella baja (116° ± 12° versus 125° ± 11° [95% CI 8.17° to 10.41°]; p < 0.01), and patients with patella baja did not have poorer Böstman scores at minimum 2-year follow-up (26.0 ± 3.2 versus 26.0 ± 3.2; p = 0.90). After controlling for potentially confounding variables such as sex, age, BMI, fracture classification, and complications, we found that fracture classification-specifically A1 (OR 6.7 [95% CI 4.8 to 9.5]), C1.3 (OR 5.0 [95% CI 3.6 to 6.9]), and C3 (OR 2.5 [95% CI 1.9 to 3.4])-deep infection (OR 10.5 [95% CI 4.2 to 26.5]; p < 0.001), and superficial infection (OR 2.4 [95% CI 1.4 to 4.4]; p = 0.003) were associated with the development of postoperative patella baja, whereas sex, BMI, and age were not. Postoperative infection was the only complication associated with patella baja.

CONCLUSION

The findings of this study underscore the importance for surgeons to be vigilant about the occurrence of patella baja after patellar fractures. In cases of the specific fracture types identified here, surgeons are encouraged to actively explore and adopt more suitable internal fixation techniques. By doing so, the incidence of postoperative patella baja may be effectively reduced, leading to better ROM and functional outcomes for patients.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Morphological Characteristics of Inferior Pole Patellar Fractures and a Finite-Element Analysis Combined With a Retrospective Clinical Study of Anchor Suture and Titanium Cable Cerclage Treatment

OBJECTIVE

Inferior pole patellar fractures (IPPFs) pose a significant challenge due to their complex fracture patterns and high risk of complications associated with current treatment methods. This study aims to (1) characterize the fracture patterns of IPPFs using fracture mapping and (2) compare the biomechanical stability and clinical outcomes of treatment with anchor suture with patellar cerclage versus Kirschner-wire tension band combined with patellar cerclage.

METHODS

(1) A retrospective analysis was conducted on 61 patients with IPPF. For each case, fracture reduction was manually simulated, with fracture lines and fragments overlaid onto a complete patella template to identify fracture patterns. (2) Finite-element models were used to analyze the mechanical properties of anchor suture and titanium cable cerclage treatment and Kirschner-wire tension band combined with patellar cerclage in treating IPPFs. Additionally, a retrospective analysis of clinical data was performed on 57 patients with IPPF (AO/OTA 34 A1) treated at our institution between January 1, 2023, and December 25, 2023. Of these, 18 patients underwent anchor suture and titanium cable cerclage (Group A), and 39 underwent Kirschner-wire tension band combined with patellar cerclage (Group B). We compared operative time, final knee range of motion, incidence of secondary surgery, postoperative complications, and functional recovery between the two groups based on medical records and follow-up results.

RESULTS

(1) IPPFs were predominantly comminuted, with fracture lines on the anterior view concentrated laterally and near the superior surface of the inferior pole. Fracture lines became more sparse as they approached the distal patella. The posterior view was similar to the anterior, with the majority of fractures near the superior surface of the inferior pole. (2) Finite-element analysis revealed no significant differences between the two groups in terms of displacement and stress. Operative time was similar between the groups (p > 0.05), as were final knee range of motion (p > 0.05) and postoperative Bostman scores (p > 0.05). Group A had no postoperative complications or readmissions, while Group B had two cases of hardware irritation and one case of knee joint infection.

CONCLUSION

The fracture lines of IPPF are varied, often comminuted, and correlate with the mechanism of injury. Biomechanical and clinical outcomes suggest that anchor suture with patellar cerclage is a viable option for stabilizing IPPF.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT06736639.

Modified Tension Band Wiring Technique for Patella Fractures: A Case Report

Patellar fractures are common injuries that compromise the extensor mechanism of the knee. Tension band wiring (TBW) is a widely accepted surgical technique for simple mid-pole fractures, but is associated with complications like wire migration and breakage. This case report presents a modified TBW technique designed to improve biomechanical stability and reduce complications. A 51-year-old female patient presented with right knee pain and swelling following a fall. Radiographs confirmed a transverse patella fracture. Surgical fixation was performed using a modified TBW technique involving triple-bundle wire stitching to enhance stability and prevent migration. Postoperative rehabilitation included early mobilization with continuous passive motion and gradual weight-bearing. Follow-up at three months demonstrated fracture union and excellent knee function without complications. The modified TBW technique demonstrated stability and allowed early functional recovery without implant-related complications. This technique may be considered for broader clinical application.

Tension band tendon-approximating cerclage for surgical fixation of patellar fractures: a novel surgical technique

Patellar fractures are potentially debilitating injuries due to loss of extensor mechanism function, resulting in an inability to extend the leg. Traditionally, these fractures have been surgically managed with open reduction and internal fixation using a tension band construct. This can be performed with K-wires or cannulated screws with suture or cable as the tension band. Plate osteosynthesis is another option that is increasing in popularity. Incorporating the tension band construct converts tensile force into a healing-compatible compressive force. However, these techniques often fail when used for comminuted patellar fractures. There is also a high reoperation rate due to metal implant discomfort. Reoperation rates have been reported as high as 41% for K-wires and 23% for cannulated screws. A more optimal technique would provide adequate reduction and strong fixation without the risk of implant irritation that can apply to all/most fracture types. We report a new technique that implements a multistrand, long-chain, ultra-high-molecular weight, polyethylene core suture material with a braided jacket of polyester (FiberWire) without the need for any associated plates, K-wires, or cannulated screws. The suture is woven to create a tension band tendon-approximating cerclage construct that incorporates the proximal and distal bone fragments as well as the patellar and quadriceps tendons. This technique can be used for both simple and comminuted fractures and provides optimal fixation strength while minimizing the complications associated with metal implants. The efficacy of this technique may lend to future studies including biomechanical and retrospective analyses.

Case Report: Bicondylar conjoined Hoffa fracture with incarcerated patella

Case

Hoffa fractures, uncommon injuries of the femoral condyle, sometimes involve both condyles, forming bicondylar fractures, typically from high-velocity trauma. We describe a 17-year-old male with an open conjoined bicondylar Hoffa fracture and a patellar fracture with incarceration following a road traffic accident. Emergency treatments included debridement, irrigation, and cannulated screw fixation. Postoperative care involved controlled range-of-motion exercises and specialized rehabilitation.

Conclusion

Despite its rare and severe nature, this conjoined bicondylar Hoffa fracture with patellar incarceration was successfully managed, showing excellent recovery. CT scans are vital for accurate injury definition and surgical planning. Anatomical reduction and rigid fixation enable early mobilization and excellent long-term outcomes.

Mo Passer (Mufasa): A Cost-Effective Alternative Suture-Passer Technique for Patella Fracture Fixation

Suture passers are indispensable instruments in orthopaedic surgery, particularly in open procedures. Commercial suture passers, while effective, can be costly and may not be readily available in all surgical settings. We present the Mo Passer (Mufasa), an innovative, cost-effective technique utilizing standard theatre materials. This paper demonstrates its application in patella fracture fixation procedures, highlighting its efficiency and economic advantages in orthopaedic surgery.

"Tension band wiring first" -an easy, fast and reproducible technique to reduce patellar fractures, a retrospective comparative study with traditional reduction technique

OBJECTIVE

To evaluate intraoperative and early postoperative clinical outcomes using the "tension band wiring first technique" to reduce C type patellar fractures.

METHODS

Sixty-four patients with C type fractures were enrolled in this study. Thirty-four patients underwent open reduction and internal fixation (ORIF) surgeries using the traditional reduction technique by pointed clamps (TRT group). The other thirty patients received the patellar fracture reduction using the "Tension band wiring first technique" (TBWFT group). All patellar fractures were treated with a cable tension band and a cerclage cable. The duration of intraoperative procedure and X-ray exposure times were recorded. All patients were followed up at 1, 3, 6, and 12 months. Bone union time was recorded. The articular surface steps of the patellas were measured. After surgery, range of motion (ROM) of the knee, and complications were evaluated, and patellar function was evaluated using the Lysholm knee scores and Böstman scores.

RESULTS

When compared to TRT group, the "Tension band wiring first technique" significantly reduced the intraoperative time and X-ray exposure times and tended to reduce the articular surface steps, though without statistical significance. In the two groups, there was no significant difference in bone union time, ROM, complications and patellar function.

CONCLUSION

The utilization of "Tension band wiring first technique" proved to be a straightforward, expeditious, and reproducible technique for reducing patellar fracture in comparison to the conventional reduction technique utilizing pointed clamps. Further studies are required to ensure the generalizability of these findings to additional patient populations at other institutions.

Radiographic and Functional Outcomes Following Resorbable Screw-Augmented Suture Fixation vs. All-Suture Fixation of Mid-pole Patellar Fractures: A Comparative Case Series

Purpose Midpole patellar fractures are traditionally fixed with an "11-8" metal tension band construct. However, this technique is rife with implant-related complications. This study aims to evaluate the radiographic and functional outcomes following "all-suture" fixation of mid-pole patellar fractures as compared to resorbable screw-augmented suture fixation. Methods We retrospectively studied a consecutive series of 18 patients, 9 each with mid-pole patellar fractures treated with all-suture fixation or suture fixation augmented with bioabsorbable cancellous screws in our institution. The hybrid fixation cohort was significantly older (p<0.01). Radiographic and functional outcomes, such as time to union, postoperative range of motion (ROM), and the presence of complications such as fracture displacement were recorded and evaluated. The minimum follow-up was one year. Results All cases achieved radiographic union by 15 weeks postoperatively except one from the hybrid fixation cohort. The average time to radiographic union was comparable (p=0.30). Twenty-two point two percent (22.2%; 2 out of 9) of the cases from each cohort had an increase in the fracture gap (>2 mm) at around four to six weeks postoperatively, for which all except one case from the hybrid fixation cohort achieved union thereafter. One patient from the hybrid fixation cohort had fibrous non-union and further fracture displacement. There was another case of mild fracture gapping and screw breakage on review of postoperative radiographs at three months from the hybrid fixation cohort. These patients recovered without surgical revision or implant removal. Conclusions Both non-metal fixation methods for mid-pole transverse patellar fractures proved to be radiographically and functionally comparable.

Complications following surgical treatment of patella fractures - a systematic review and proportional meta-analysis

PURPOSE

The aim of this systematic review and proportional meta-analysis was to identify complications of surgical treatment of patella fractures and to estimate their incidence. We extended existing knowledge on this topic by including several more recent and large-scale studies.

METHODS

This systematic review and meta-analysis were performed in accordance with the Cochrane Handbook for systematic reviews of interventions. After searching in PubMed, MEDLINE, EMBASE, Cochrane Library, and OpenGrey, all studies after 2000, with study populations > 100 patients, including only patients > 18 years and follow-up > 30 days, were included. Two independent authors assessed the literature search and extracted the data. The risk of bias was assessed using the Newcastle-Ottawa Quality Assessment Scale. The meta-analysis was performed on complications pooled in infections, nonunion, symptomatic implant removal, and fixation failure.

RESULTS

The data on complications were available from 14 studies, including a pool of 5659 patients. The most common complication was symptomatic implant removal, affecting.

CONCLUSION

Surgically, treatment of patella fractures was associated with a high risk of complications. The most common complication was symptomatic implant removal, affecting 29.6% of patients. Other complications stated were fixation failure 5.2%, infections 3.1% and nonunion 1.7%.

Novel technique for comminuted patellar fixation using suture tape in spiderweb configuration

INTRODUCTION

Patella fractures account for 1% of skeletal fractures in orthopedic surgery. Simple two-part patella fractures are uncommon; most fractures are comminuted with significant articular involvement. Traditionally, patella fractures have been fixed using a tension band technique with cerclage wire, which has several complications including soft-tissue irritation, implant migration, and breakage, leading to secondary implant removal in up to 37% of patients. Newer fixation methods using cannulated screws, hook plates, mesh plates, and locking plates show promise but are costly and require extensive soft-tissue dissection. There is a need for a better alternative, especially for the elderly with osteoporotic bones.

RECENT DEVELOPMENTS

Various authors have described patellar fixation techniques augmented with sutures and suture tape, showing satisfactory outcomes. This paper proposes a novel all-suture tape method for patellar fixation, suitable for common types of patella fractures including AO 34C1.1 (transverse), AO 34C2 (transverse and split), and 34C3 (comminuted). Suture tape is biomechanically superior in both soft tissue and bone.

OPERATIVE TECHNIQUE

The patient is laid supine with the knee in full extension. A standard anterior midline approach is adopted. After reducing the fracture fragments and securing them with K-wires, non-absorbable suture tapes are used instead of cerclage wire. The tapes are passed multiple times through the soft tissue, creating loops that are then tensioned to compress the fracture fragments. The technique is completed by creating a tension band fixation with additional suture tapes.

EXPECTED OUTCOMES

This technique offers several benefits, including reduced operative time, minimized soft-tissue dissection, and lower risk of implant prominence and irritation. The suture tape's superior tensile strength and low tissue reactivity reduce complications and the need for secondary surgeries. Early results from two cases show union achieved at 3 months without complications, with patients regaining full range of motion.

CONCLUSION

This preliminary technical paper demonstrates the feasibility of using non-metallic implants for patella fracture fixation. The proposed method shows promising results, suggesting a potential shift in the approach to fracture fixation. Further research and larger cohort studies are needed to validate these findings.

An innovative anti-rotation tension band wiring for treating transverse patellar fractures: finite element analysis and mechanical testing

BACKGROUND

The displacement and rotation of the Kirschner wire (K-wire) in the traditional tension band wiring (TBW) led to a high rate of postoperative complications. The anti-rotation tension band wiring (ARTBW) could address these issues and achieve satisfactory clinical outcomes. This study aimed to investigate the biomechanical performance of the ARTBW in treating transverse patellar fracture compared to traditional TBW using finite element analysis (FEA) and mechanical testing.

METHODS

We conducted a FEA to evaluate the biomechanical performance of traditional TBW and ARTBW at knee flexion angles of 20°, 45°, and 90°. Furthermore, we compared the mechanical properties under a 45° knee flexion through static tensile tests and dynamic fatigue testing. The K-wire pull-out test was also conducted to evaluate the bonding strength between K-wires and cancellous bone of two surgical approaches.

RESULTS

The outcome of FEA demonstrated the compression force on the articular surface of ARTBW was 28.11%, 27.32%, and 52.86% higher than traditional TBW at knee flexion angles of 20°, 45°, and 90°, respectively. In mechanical testing, the mechanical properties of ARTBW were similar to the traditional TBW. In the K-wire pull-out test, the pull-out strength of ARTBW was significantly greater than the traditional TBW (111.58 ± 2.38 N vs. 64.71 ± 4.22 N, P < 0.001).

CONCLUSIONS

The ARTBW retained the advantages of traditional TBW, and achieved greater compression force of articular surface, and greater pull-out strength of K-wires. Moreover, ARTBW effectively avoided the rotation of the K-wires. Therefore, ARTBW demonstrates potential as a promising technique for treating patellar fractures.

Dorsal Hook Plating of Patella Fractures With Immediate Range of Motion Results in Reliable Fixation, Low Implant Removal Rates, and Satisfactory Clinical Outcomes

OBJECTIVES

To evaluate radiographic and clinical patient-reported outcomes following dorsal hook plating of displaced patella fractures with permittance of immediate postoperative active closed chain range of motion.

METHODS

DESIGN

Retrospective review of prospectively collected data.

SETTING

Urban academic level 1 trauma center.

PATIENT SELECTION CRITERIA

Adult patients with displaced patella fractures (OTA/AO 34C1-3) who underwent dorsal plating with immediate range of motion between 2018 and 2023.

OUTCOME MEASURES AND COMPARISONS

Numerical Rating Scale for Pain, Knee Outcome Score (KOS-ADL), Tegner-Lysholm score, radiographic union, and wound complications were collected.

RESULTS

Sixty-one patients were included (47 female) with an average age of 63 years (SD 14.7, range 22-86 years). The mean BMI was 24.2 (SD 3.6, range 16.6-33.3). There were 13 34-C2 and 48 34-C3 fractures. All but 2 patients (96.7%) achieved bony union after the index procedure. 89% (n = 54) of patients completed outcome surveys with at least 6-month follow-up. Six patients (9.8%) underwent removal of plate implant at a mean of 15.1 months postoperatively. The mean KOS-ADL score was 91.4, the mean Tegner-Lysholm score was 78.1, and the mean NRS was 2.7.

CONCLUSIONS

Dorsal hook plating offers secure fixation to allow early range of motion, reliable fixation with low nonunion and implant failure rates, low implant removal rates, and satisfactory patient-reported outcomes.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Anterior variable angle locking neutralisation plate superiority over traditional tension band wiring for treating transverse patella fractures

Purpose

This paper investigates the biomechanical benefits of using hybrid constructs that combine cannulated screws with tension band wiring (TBW) cerclage compared to cannulated screws with anterior Variable Angle locking neutralisation plates (VA LNP). These enhancements can bear heavier loads and maintain the repaired patella's integrity, in contrast to traditional methods.

Method

Eighteen fresh-frozen human cadaver patellae were carefully fractured transversely at their midpoints using a saw. They were then divided into two groups of nine for subsequent utilisation. Fixation methods included Cannulated Screw Fixation added with either TBW or VA LNP Fixation Technique. Cyclic loading simulations (500 cycles) were conducted to mimic knee motion, tracking fracture displacement with Optotrak. After that, the constructs were secured over a servo-hydraulic testing machine to determine the load-to-failure on axial mode.

Results

The average fracture displacement for the anterior neutralisation plate group was 0.09 ± 0.12 mm, compared to 0.77 ± 0.54 mm for the tension band wiring with cannulated screw group after 500 cyclic loading. This result is statistically significant (p = 0.004). The anterior neutralisation plate group exhibited a mean load-to-failure of 1359± 21.53 N, whereas the tension band wiring group showed 780.1 ± 22.62 N, resulting in a significant difference between the groups (p = 0.007).

Conclusion

This research highlights the superior biomechanical advantage of VA LNP over TBW for treating simple transverse patella fractures with two cannulated screws. It also highlights how the TBW is still a valuable option considering the load-to-failure limit.

Level of Evidence

Not Applicable.

Reconstruction of patella fractures with the tension band technique: A review on clinical results and tips and tricks

INTRODUCTION

The goals of surgical treatment of patellar fractures are a biomechanically stable joint and congruent restoration of the retro patellar joint surface. Surgical treatment strategies for patellar fractures have evolved from tension band in combination with wire cerclages to new devices.

METHODS

The modified anterior tension band (MATB) technique for fixation of patellar fractures consists of two longitudinal 1.8 mm Kirschner wires (K-wires) and an 18-gauge stainless steel wire looped in a figure-of-8 pattern over the anterior aspect of the patella. The K-wires should be inserted 5 mm from the anterior cortical surface of the patella, parallel in the coronal and sagittal planes. For mechanical reasons, the wire should be the closest to the anterior aspect of the bone. This construct converts the anterior tensile forces generated by the extensor mechanism and knee flexion into compressive forces on the anterior aspect of the fracture site. The MATB is the most widely accepted method of internal fixation for transverse and comminuted patellar fractures. Only a careful implementation of the MATB in all its phases will provide the best mechanical construct and the least aggressive construct for the soft tissues, allowing early re-education without complications.

RESULTS

Good to excellent clinical results (64-100 %) have been reported with MATB for fixation of patellar fractures. Good to excellent range of knee motion and satisfactory results have been reported despite a high percentage (up to 60 %) of secondary procedures, mainly for removal of symptomatic hardware.

CONCLUSION

This article provides an overview of the use and results of the MATB technique for patellar fractures and the means to improve results with this technique.

Use of metatarsal hook plates in the treatment of multifragmentary patellar fractures - A case series

The surgical management of patellar fractures typically yielded satisfactory results; however, in situations involving multifragmented patellar fractures or those affecting the inferior pole, it became imperative to employ alternative osteosynthesis techniques that enhanced stability, enabled early rehabilitation initiation, prevented implant failure, and avoided reduction loss before fracture consolidation. In this context, an unconventional osteosynthesis alternative was presented, utilizing an anatomically designed hook plate originally intended for the fifth metatarsal. This technique was successfully applied in three patients with multifragmentary patellar fractures, allowing stable fixation of small or marginal fragments through the plate's hooks without compromising vascularity. Fracture consolidation was achieved without reduction loss, and owing to its low profile, patient discomfort and irritation were minimized compared to traditional tension band or wiring techniques. This approach suggested the potential to forego early plate removal, thereby contributing to a more effective management of patellar fractures.

Level of evidence

IV.

High risk of complications following surgical treatment of patella fractures - a cross-sectional study of 798 patients with mean 6.4 years follow-up

PURPOSE

This study aimed to investigate the incidence of early and late complications following treatment of patella fractures. Secondary aims were to investigate the association between early and late complications and the patient-reported outcome measurement, the Knee Injury and Osteoarthritis outcome score (KOOS).

METHODS

Cross-sectional study including all patients recorded with a patella fracture residing in the Northern Region of Denmark between 2010 and 2020. Early (before 3 months) and late complications were investigated by retrospective review of charts and x-rays. All patients were invited to participate in the study by reporting current knee-specific symptoms. The KOOS was used to investigate patient-reported knee-specific symptoms.

RESULTS

Seven hundred ninety-eight patients were included in the study. A total of 532 (67%) patients were treated conservatively, and 266 (33%) patients underwent surgery. The mean age at the time of fracture was 66.8, ranging from 6 to 103 years of age. The mean follow-up time was 6.4 years, ranging from 1.1 to 12.3 years follow-up. Overall, the rate of complications was 26%. Overall, the rate of complication for the surgical group was 57% and for the conservative group 4%. The most common early complication was the loss of reduction followed by the removal of symptomatic hardware. The most common late complication was the removal of symptomatic hardware and knee arthroscopy. In all the five KOOS subscales (Pain, Symptoms, ADL, Sport/Rec, and QOL), patients presenting with early and late complications reported statistically significantly worse scores than those without complications.

CONCLUSION

The overall incidence of complications in patients presenting with a patella fracture was 26%, with a mean follow-up time of 6.4 years. In the surgical group, 57% of patients experience at least one complication during the follow-up period. Early and late complications were significantly associated with worse KOOS subscale  scores.

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.

Evolution in the Management of Patella Fractures

Patella fractures usually occur as a result of direct trauma to the anterior knee joint, indirect injury as a result of eccentric muscle contraction, or rapid knee flexion against a contracted quadriceps muscle. The patella functions as part of the extensor mechanism of the knee, where large forces are transmitted, and its subcutaneous nature has made treatment of patella fractures a challenge. In this review article, we evaluate how the management of these fractures has evolved over time and the advantages associated with the various treatment techniques. There are few comparative studies looking at the different treatment types for fractures of the patella, with the goal of achieving a functional extensor mechanism with low rates of post-traumatic arthritis and metal-work irritation.

Application of Staged Negative Pressure Wound Therapy and Flap Surgery for Infection Control After Patellar Internal Fixation Surgery

The anatomic position of the patella is superficial, making it vulnerable to injuries. Treatment of patella infection after internal fixation surgery remains a big challenge due to minimal soft tissue coverage and vital tissue exposure. Forty-two patients aged 10 to 59 years were admitted to the institution's burn unit between January 2010 and December 2019. Each presented with infection after patellar fracture surgery. Twenty-seven infections were superficial, whereas 15 were deep with pyogenous arthritis of the knee. Negative pressure wound therapy (NPWT) was applied after radical debridement to remove necrotic subcutaneous tissues and internal fixation devices. In addition, cases with septic arthritis were irrigated continuously with normal saline. After 5 to 10 days of NPWT treatment and irrigation, wound infection was well controlled. Afterward, 42 wounds were resurfaced with pedicled flaps, the 42 patients received 17 reverse-flow anterolateral thigh (ALT) perforator flap, 12 medial sural artery perforator flaps, 7 gastrocnemius musculocutaneous flaps, as well as 6 saphenous artery flaps. Thirty-seven flaps survived uneventfully. However, 3 flaps developed venous congestion in the distal end. Two flaps developed tip necrosis. All patients were followed up between 3 and 48 months. Infection beneath the flap occurred in 3 patients and healed after an additional debridement surgery. The staged NPWT and flap surgery strategy focus on thorough debridement and immediate internal fixation devices removal, effective fracture fixation, efficient NPWT application, targeted administration of antibiotics, and adequate soft tissue coverage. This study established that the procedure was effective in infection control after patellar internal fixation surgery.

Can multiple miniplates improve the treatment of comminuted patellar fracture?

BACKGROUND

We have applied primarily multiple locking compression miniplates in treating multifragmentary, comminuted patellar fracture in combination with conventional fixation methods.

METHODS

Medical and radiologic data were retrospectively reviewed for the patients surgically fixated with locking compression miniplates in patellar fracture of AO/OTA 34-C3. The primary outcome was bone union at the final follow-up, and the secondary outcomes were functional outcomes and postoperative complications associated with the procedure. For the functional assessment, the Lysholm score, Tegner scores, and the knee range of motion was compared.

RESULTS

A total of twenty patients with AO/OTA 34-C3 patellar fracture were included in the study with an average follow-up period of 15 months (range:11 ~ 18 months) between June 2018 and November 2021. Eleven male and nine female patients presented an average age of 57.15 years. The primary fracture union was seen in all twenty patients, and the average time to the union was 15.6 weeks on serial radiograph follow-up. All patients did not show any postoperative complications, such as fixation failure, infection, or revision operations. Postoperatively, all patients achieved an average range of motion of 130 degrees, and the Lysholm and Tegners scores showed an average of 90.4 and 5.0 at the final follow-up, retrospectively.

CONCLUSION

Fixations with miniplates in comminuted patellar fractures can be a useful option for effective osteosynthesis due to their versatile, efficient, and low-profile nature.

Incidence of postoperative complications in patellar fractures related to different methods of osteosynthesis procedures - a retrospective cohort study

BACKGROUND

Patellar fractures have a comparatively low incidence compared to all fracture frequencies of the musculoskeletal system. However, surgical management is crucial to prevent postoperative complications that affect the knee joint. The purpose of the present study was to evaluate the incidence of postoperative complications and onset of postoperative osteoarthritis related to the chosen technique of patellar fracture management.

METHODS

In a retrospective cohort study consecutive managed, isolated patella fractures were reviewed for demographic data, trauma mechanism, patella fracture type, fixation technique and postoperative complications. The results were documented radiographically and clinically and analysed statistically. The reporting followed the STROBE guidelines.

RESULTS

A total of 112 patients were eligible for data evaluation. Surgical management of comminuted patellar fractures with small fragment screws showed significant fewer postoperative complications compared to other fixation techniques (8%, p < 0.043). The incidence of posttraumatic infection was significantly higher following the hybrid fixation technique with cannulated screws and tension wire than following the other analysed techniques (p = 0.024). No postoperative wound infection was observed after screw fixation or locking plate fixation. Symptomatic hardware was most frequently seen after tension-band fixation. Onset of posttraumatic osteoarthritis was most often found after the hybrid fixation technique (55%).

CONCLUSION

Surgical management of patellar fractures remains crucial but fracture fixation using plating systems or small fragment screws is least associated with postoperative complications.

TRIAL REGISTRATION

Trial registration number (DRKS):00027894.

A novel technique for treating simple transverse patellar fractures using cannulated screws: a cadaveric and clinical study

BACKGROUND

Tension band wiring (TBW) has conventionally been used for the open reduction and internal fixation of the patella. However, it suffers from distinct disadvantages such as large incision, implant irritation, and need for subsequent implant removal. Here, we propose a novel technique using closed reduction and percutaneous fixation with three cannulated screws (TCS), which may be an alternative to this established conventional technique. Although some researchers have proposed alternative methods including closed reduction and cannulated screw fixation, with or without additional wires through the screws, and arthroscopic-assisted reduction and fixation, there are few studies that focus on the biomechanical stability of percutaneous fixation using only cannulated screws. Thus, the purpose of this study was to evaluate TCS versus TBW for simple transverse patellar fractures in cadaveric and patients' level, aiming to determine whether TCS show superiority over TBW in terms of biomechanical stability in a cadaveric study with benign clinical feasibility and outcomes in patients.

METHODS

We conducted a cadaveric study with 15 knee specimens that had simple transverse patellar fractures. We used two fixation techniques: TBW (group A, n = 6) and TCS (group B, n = 9). We applied sinusoidal forces (25 N-125 N) at 1/5 Hz and 90° knee flexion to simulate knee movement. We compared the displacements at the fracture site between the two groups. We also used the same technique in a total of 23 patients and followed up them for at least 1 year.

RESULTS

TCS demonstrated favourable biomechanical stability in the cadaveric study. The technique also performed excellently in terms of postoperative pain, knee function recovery, and complication rates during the follow-up period.

CONCLUSIONS

The technique provides a surgical treatment option with small incisions, minimal soft tissue irritation, and possibly lower removal rate of bothersome material.

Patella Fracture Fixation With Novel Wagon Wheel Construct Versus Tension-Band Construct: A Technical Trick

SUMMARY

Internal fixation of patella fractures remains technically challenging. Cannulated screws with an anterior tension band have been associated with high rates of implant prominence, and fracture comminution can make appropriate application of a tension band impractical. We present the results of a novel technique using a transtendinous/transligamentous mini-fragment plate positioned peripherally around the patella with radially directed screws: termed the wagon-wheel (WW) construct. Compared with a cohort of fractures treated with cannulated screws with an anterior tension band, there was no difference in final range of motion and rate of nonunion. The WW construct had a significantly decreased incidence of symptomatic implants (5% vs. 32%, P = 0.02), rate of reoperation (9% vs. 38%, P = 0.018), dependency on gait aids (10% vs. 38%, P = 0.031), and a faster time to union (HR: 2.2; 95% CI, 1.28-3.95, P = 0.005). In summary, the WW was designed with the goal of obtaining peripheral plate fixation to maximize fragment-specific fixation while minimizing implant prominence. Patients treated with the WW demonstrated reduced rates of implant prominence and reoperation.

Pin and Wire System Fixation for the Treatment of Comminuted Patella Fractures

We describe the wiring technique and evaluate the radiographic and clinical outcomes of treatment with a pin and wire system (PWS) for comminuted patella fractures. From June 2013 to October 2018, 33 patients with comminuted patella fractures were treated using a PWS. Open reduction and internal fixation was performed with multiple pins and a wire. All patients were allowed full weight bearing without a brace. Radiographs were obtained to evaluate bone union, implant breakage, back-out of pins, and intra-articular gaps and step-off. Clinical outcomes and postoperative complications were assessed at final follow-up examination. All fractures were united. Thirteen cable wires in 13 patients were partially broken without displacement of fracture at an average of 7.4 months (range, 1-19 months) postoperatively. The average preoperative, postoperative, and final follow-up intra-articular gap and step-off were 11.7 mm, 0.5 mm, and 0.03 mm and 6.6 mm, 0.4 mm, and 0.2 mm, respectively. The average postoperative pin displacement was 0.1 mm (range, 0-0.8 mm). Deep infection was not observed after the surgery. The implant removal rate was 21% (7 of 33). Among these, the symptomatic implant removal rate was 9% (3 of 33). Additionally, 3 of 7 patients with implant removal had broken wires. The average flexion and extension of knee joints were 139.7° (range, 120°-150°) and -0.9° (range, -10° to 0°), respectively. A PWS prevents back-out of the pins and reduces intra-articular gaps and step-off distances to acceptable levels, even if the cable wire is partially broken. Therefore, a PWS is a good treatment option for comminuted patella fractures. [Orthopedics. 2023;46(5):291-296.].

Comparison of a minimally invasive osteosynthesis technique with conventional open surgery for transverse patellar fractures

PURPOSE

The study aims to compare the efficacy and safety of a new minimally invasive osteosynthesis technique with those of conventional open surgery for transverse patellar fractures.

METHODS

It was a retrospective study. Adult patients with closed transverse patellar fracture were included, and with open comminuted patellar fracture were excluded. These patients were divided into minimally invasive osteosynthesis technique (MIOT) group and open reduction and internal fixation (ORIF) group. Surgical time, frequency of intraoperative fluoroscopy, visual analogue scale score, flexion, extension, Lysholm knee score, infection, malreduction, implant migration and implant irritation in two groups were recorded and compared. Statistical analysis was performed by the SPSS software package (version 19). A p < 0.05 indicated statistical significance.

RESULTS

A total of 55 patients with transverse patellar fractures enrolled in this study, the minimally invasive technique was performed in 27 cases, and open reduction was performed in 28 cases. The surgical time in the ORIF group was shorter than that in the MIOT group (p = 0.033). The visual analogue scale scores in the MIOT group were significantly lower than those in the ORIF group only in the first month after surgery (p = 0.015). Flexion was restored faster in the MIOT group than that in the ORIF group at one month (p = 0.001) and three months (p = 0.015). Extension was recovered faster in the MIOT group than that in the ORIF group at one month (p = 0.031) and three months (p = 0.023). The recorded Lysholm knee scores in the MIOT group were always greater than those in the ORIF group. Complications, such as infection, malreduction, implant migration, and implant irritation, occurred more frequently in the ORIF group.

CONCLUSION

Compared with the ORIF group, the MIOT group reduced postoperative pain and had less complications and better exercise rehabilitation. Although it requires a long operation time, MIOT may be a wise choice for transverse patellar fractures.

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.

Achieving Rapid Healing and Low Complication Rates in Patellar Fracture Fixation: The Benefits of Cerclage and Figure-of-Eight Configuration

Background and objective Patellar fractures account for around 1% of all fractures. Conservative treatment is advised in patients without any incompatibility of articular surfaces or those with intact extensor mechanisms. More than a 2-mm articular gap due to fracture warrants surgical intervention. Tension band wiring (TBW) is a commonly used practice for fixation, However, there is still controversy about its effectiveness and complications arising due to the hardware. Modification of this technique by using K-wires has been considered a method of choice, but this technique is associated with complications due to K-wires. The Pyrford technique is a method for patellar fracture fixation by circumferential cerclage and anterior TBW. We employed the figure-of-eight configuration over the circumferential wire. This study aimed to analyze the outcomes of TBW of the patella without K-wires by assessing the rate of complication and functional outcomes. Materials and methods A total of 38 patients with OTA 34C type, simple and comminuted type of patella fractures aged between 22 and 70 years were treated with circumferential cerclage and figure-of-eight TBW. All patients underwent patellar fixation with cerclage and through direct purchase of SS wire via quadriceps and patellar tendon. Patients were followed up for one to three years. We analyzed differences in the range of motion, fracture reduction, fracture healing time, Bostman score for knee function, and complications. Results The mean age of the patients was 45 years. After TBW without K-wires, fracture healing and functional outcomes were satisfactory according to patient feedback and clinocoradiological examinations. Of note, 35 out of 38 patients (92%) had gained up to 90 degrees of active flexion at the end of one week. One patient (2.42%) developed a superficial infection. All fractures had achieved union at the end of 16 weeks. Malunion or nonunion was not noted in any of the cases. There was no case of implant removal. The average Bostman score at the 12-month follow-up was 28.5 ±1.5. The incidence of complications due to K-wire was nullified. Conclusion Based on our findings, the described method leads to better functional outcomes, decreasing hardware-related complications, and can be used in simple as well as comminuted fractures. The fracture healing and functional outcomes and rate of complications were satisfactory.

Closed Reduction and High-Strength Sutures for Transverse Patella Fractures: A Retrospective Analysis

Objective

This study aimed to investigate the clinical efficacy of closed reduction high-strength sutures combined with Nice knots in treating transverse patella fractures.

Method

We retrospectively analyzed the clinical data of 28 patients who underwent surgery for transverse patella fractures from January 2019 to January 2020. Twelve cases of the study group were treated with closed reduction high-strength sutures combined with Nice knots, and 16 cases in the control group were treated with tension band wiring. Observations included patellar healing, follow-up knee mobility with Böstman score, Lysholm score, surgical data, postoperative complications, and secondary surgery rate.

Result

No statistically significant difference was observed between the two groups in the Patient demographic data, with a mean follow-up of 13.14 ± 1.58 months. There was no delayed healing or deep infection in the two groups. In the control group, 2 cases of internal fixation failure and 1 case of superficial infection were observed. The differences in mean fracture healing time, follow-up Böstman score, Lysholm score and knee mobility between the two groups were not statistically different. However, the differences were statistically significant for the duration of surgery, Incision length, intraoperative bleeding and the secondary surgery rate was lower in the study group.

Conclusion

Closed reduction high-strength sutures have good clinical efficacy in treating transverse patella fractures, with the advantages of shorter duration of surgery and Incision length,less intraoperative bleeding and no secondary removal.

3D reduction combined with the modified Kirschner-wire tension band for the treatment of comminuted patella fracture

PURPOSE

A novel 3D reduction method combined with a modified Kirschner-wire tension band (3D MKTB) fixation method to treat comminuted patella fractures was introduced in this study. This study aims to evaluate the effectiveness and practicality of this novel technology.

METHODS

This study is a retrospective case series study. Twenty-eight patients with closed comminuted patella fractures were treated with the novel 3D MKTB fixation method. Radiographs of the knee were obtained at the routine follow-up to assess fracture healing and widening of the articular step-off. Clinical outcomes including the degree of pain on a visual analogue scale (VAS), range of motion, Lysholm, and Bostman grading scales were measured at the last follow-up. The mean follow-up was 39.8 ± 10.5 (range 26-62) months.

RESULTS

All patients had bony union at a mean of 11.4 ± 1.4 (range 9-14 weeks) weeks based on X-ray. No patient had evidence of internal fixation failure. Only two patients suffered from surgical complication. One patient suffered from postoperative superficial infection, and one patient suffered from internal fixation irritation. Articular step-off larger than 2 mm was not seen in any cases. The average VAS-related pain score was 0.5 ± 0.5 (range 0-1) points. The average range of motion was 0-138.6° ± 11.9° (range 90°-155°), all patients had full knee extension. The mean Lysholm and Bostman scores were 92.9 ± 3.5 (range 86-100 points) points and 28.5 ± 1.3 (range 24-30 points) points, respectively.

CONCLUSION

The novel 3D reduction technique combined with the modified Kirschner-wire tension band technique is an effective, safe, and simple treatment option for comminuted patella fractures.

LEVEL OF EVIDENCE

IV.

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.

Adjunct neutralization plating in patella fracture fixation: a technical trick

Patella fracture outcomes are positive overall; however, in some cases, traditional fixation methods result in complications, including loss of fixation and irritable hardware requiring removal. We present a technique of plate fixation that we believe has the potential to improve stability and is less offensive in more comminuted fracture patterns. Improved stability should allow unfettered advancement of rehabilitation without concern for loss of fixation. Lower profile fixation offers a potential for diminishing the presence of irritating hardware requiring removal. We present our technique for using plate fixation to augment more complex patella fracture patterns.

The clinical outcomes and complications of combined fixation with cannulated screws and the modified Pyrford technique for the treatment of transverse patellar fractures: a case series study

Background

Transverse patellar fractures can be fixed using various techniques. The purpose of the current study was to assess the clinical outcomes and complication rate of a combined fixation technique using cannulated screws and the modified Pyrford technique with nonabsorbable polyester sutures.

Methods and patients

Between January 2015 and February 2021, 26 transverse patellar fractures were fixed with this combined technique. Preoperative data were collected from patients with transverse patellar fractures who were followed up for at least 12 months. At each follow-up visit, plain radiographs were taken. At the 12-month postoperative follow-up, range of motion of the affected knee joint and clinical outcomes, as evaluated by the Bostman scoring system, were recorded.

Results

The average Bostman score at the 12-month postoperative follow-up was 28.3 ± 1.5. Furthermore, the average extension and flexion of the knee joint were 1.2 ± 2.1 and 125.6 ± 6.7 degrees, respectively. One patient experienced delayed bone union and one experienced superficial wound infection. There were no other postoperative complications. One patient required removal of the device for social-psychological reasons.

Conclusions

The combined fixation technique with cannulated screws and the modified Pyrford technique with suture materials produced excellent clinical outcomes and a low rate of complications in the treatment of transverse patellar fractures.

Suture tension band fixation vs. metallic tension band wiring for patella fractures - A biomechanical study on 19 human cadaveric patellae

PURPOSE

Traditional tension band fixation of patella fracture is associated with high reoperation rates. The purpose of the study was to assess strength of fixation in patella fractures treated with either a non-metallic all suture-based technique or traditional metallic tension band wiring.

METHODS

Ten paired human cadaveric specimens were included. A transverse fracture was created, reduced and fixated with a non-metallic or metallic approach. Non-metallic fixation was done according to a previously published technique, metallic fixation was done according to AO description. Specimens were fixed in 90° of flexion and underwent 200 cycles of loading by pulling the Quadriceps tendon to 300 Newton. Fracture displacement was optically monitored. Primary outcome was fracture displacement after 200 cycles compared to the first cycle. Subsequently, load-to-failure was assessed by a monotonic pull to 1000 N.

RESULTS

For cyclic loading analysis, one specimen from each group was excluded due to machine synchronization, resulting in a total population of 18 specimens. Median (min-max) fracture displacement was 0.65 mm (0.06-1.3) in the non-metallic group and 0.68 mm (0-1.23), (p=0.931) in the metallic group. No difference in displacement was found between the two groups in the repeated measures analysis of variance (p=0.5524). For load-to-failure analysis one specimen was excluded due to machine synchronization, resulting a total population of 19 specimens. 2/9 specimens failed in the non-metallic group (at 979 and 635 N) and 2/10 failed in the metallic group (745 and 654 N).

CONCLUSION

Non-metallic technique is a biomechanically viable alternative to traditional tension band fixation and it can hopefully lead to fewer implant-related complications.

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.

Clinical Outcomes of Cannulated Screws versus Ring Pin versus K-Wire with Tension Band Fixation Techniques in the Treatment of Transverse Patellar Fractures: A Case-Control Study with Minimum 2-Year Follow-Up

Purpose. K-wire with tension band (KTB) technique has long been the primary surgical method for transverse patella fractures; however, it also has shortcomings. This study is aimed at evaluating the three different techniques to see whether the cannulated screw tension band (CSTB) or ring pin tension band (RPTB) techniques could decrease complications and achieve better knee function compared with KTB. Methods. We conducted a retrospective comparison of the KTB, CSTB, and RPTB fixation techniques. We selected and reviewed 90 patients (30 patients in each fixation group) with follow-up at least 2 years. Duration of operation, intraoperative blood loss, mean healing time, visual analog scale score, range of motion, Böstman score, Iowa knee score, modified Lysholm rating scale, and postoperative complications were compared. Multivariate analyses were performed to identify the independent risk factors for fracture healing time, postoperative complications, and knee function recovery. Results. After adjusting for confounding factors, multivariate regression analysis revealed that CSTB was 0.26 times (95% CI: 0.08-0.86, $p=0.027$ ) less likely to prolong fracture healing time, 0.20 times (95% CI: 0.06-0.64, $p=0.007$ ) lesser risk of postoperative complications, and more than four times (95% CI: 1.41-13.56, $p=0.011$ ) as likely to improve the knee function score compared with KTB. Besides, RPTB were also superior to KTB in reducing the incidence of postoperative complications (OR: 0.21, 95% CI: 0.07-0.64, $p=0.006$ ) and improved knee function score (OR: 3.96, 95% CI: 1.30-12.08, $p=0.016$ ); however, the CSTB group being more superior. In addition, AO/OTA C2 fractures (OR, odds ratio: 10.68, 95% CI: 1.30-87.70, $p=0.027$ ) and high-energy fracture (OR: 8.78, 95% CI: 1.57-49.17, $p=0.013$ ) were also associated with prolonged fracture healing time but not with postoperative complications and knee function. No significant differences in related indicators such as gender, age, BMI, AO/OTA classification, fracture side, injury mechanism, duration of operation, and intraoperative blood loss were detected among the three groups. Conclusion. This study demonstrated that the CSTB technique is superior to KTB and RPTB techniques in reducing the incidence of postoperative complications, and it also has advantages in accelerating fracture healing, achieving better VAS, ROM, and functional recovery. Further long-term large-sized prospective randomized trials are needed to evaluate the efficacy of the KTB in treating transverse patellar fractures.

The radiographic soft tissue thickness is associated with wound complications after open reduction and internal fixation of patella fractures

Background

Displaced patella fracture is commonly treated with open reduction and internal fixation (ORIF). Wound complications after surgery often lead to prolonged hospitalization and dissatisfaction of patients. Periarticular adiposity and swelling may be associated with wound complications. The purpose of this study is to determine the relationship between periarticular soft tissue thickness and wound complications after ORIF of patella fractures.

Methods

We retrospectively studied 237 patients undergoing ORIF for patella fractures from June 2017 to February 2021 at our institution. We established periarticular soft tissue thickness ratio (PSTTR) to evaluate soft tissue status on lateral knee X-ray radiographs. Univariate analysis was performed to identify the association between PSTTR and postoperative wound complication. A receiver-operating characteristic (ROC) curve analysis was performed to evaluate the predictive value of PSTTR.

Results

The incidence of postoperative wound complication was 10.5%. Minor wound complication occurred in 24 patients, and major wound complication occurred in one patient. The average femoral PSTTR (fPSTTR) was 0.94 ± 0.17 and the average tibial PSTTR (tPSTTR) was 0.66 ± 0.16. fPSTTR proved to be associated with postoperative wound complication. In the ROC analysis of fPSTTR predicting postoperative wound complication, the area under curve (AUC) was 0.676, which indicated a moderate predictive value.

Conclusions

PSTTR was a feasible method to assess periarticular soft tissue. The increased fPSTTR was associated with wound complications after ORIF of patella fractures.

Surgical excision of bilateral patella stress fractures in an elite marathon runner

Vertical stress fractures of the patella are rare, with only a handful of bilateral cases reported. Stress fractures in the athletic community are often due to repetitive strain and submaximal loading, with minimal recovery time. An Olympic marathon runner in her 30s presented with right anterolateral knee pain. MRI revealed an acutely displaced vertical fracture of the lateral patella. After failure of non-operative treatment, she underwent surgical excision of the fracture fragment and lateral patellofemoral retinacular repair. Despite return to light training pain-free 3 weeks after surgery, she presented 2 months later with a contralateral vertical patella stress fracture. On this occasion, early operative treatment was performed with early return to training and resolution of symptoms.This is the first reported case of bilateral vertical patellar stress fractures in an athlete treated with excision of the fracture fragment. This is an excellent option for elite athletes who require a quick postoperative recovery, complete resolution of symptoms and early return to preinjury level of sport.

Surgical factors associated with symptomatic implant removal after patella fracture

OBJECTIVES

To determine whether certain types of fixation and other factors associated with the fixation could be identified that predict an increased risk of symptomatic implant removal.

METHODS

We conducted a retrospective cohort study at our urban academic level 1 trauma center. Patients aged ≥18 years who underwent operative fixation for patella fracture were included. The primary outcome was symptomatic implant removal after operative fixation.

RESULTS

Of the 186 study patients (mean age, 44 [SD 17] years, 65% male), 53 patients (28.5%) underwent symptomatic implant removal. Modifiable risk factors for symptomatic implant removal included the use of Kirschner (k)-wires (OR: 4.93; 95% CI, 1.89-14.10; p < 0.001), and a trend towards significance for implant prominence >5 mm (OR: 2.57; 95% CI, 0.93-7.93; p = 0.07). Symptomatic implant removal was also less likely in patients >45 years of age (OR: 0.14; 95% CI, 0.06-0.34; p < 0.01), of a racial minority (OR: 0.40; 95% CI, 0.17-0.88; p = 0.03), and a body mass index >25 kg/m² (OR: 0.39; 95% CI, 0.18-0.84; p = 0.02). The final model demonstrated excellent prognostic performance, with an AUC of 0.83 (0.76-0.90).

CONCLUSION

We identified both modifiable and non-modifiable factors associated with symptomatic implant removal in patients with patella fractures. Surgeons should be aware that the use of k-wires and any implant prominence exceeding 5 mm might be associated with increased odds of symptomatic implant removal in patients with patella fractures.

Epidemiology, classification and treatment of patella fractures: an observational study of 3194 fractures from the Swedish Fracture Register

Background

Basic epidemiological data on patella fractures derived from large nationwide and multicenter studies are scarce. This observational register study describes patient epidemiology, fracture classification and treatment of patella fractures in adults in a Swedish population.

Methods

We conducted an observational study on data derived from the Swedish Fracture Register (SFR) on all patella fractures classified as non-periprosthetic and non-pathological, registered between 2014 and 2018 in individuals aged ≥ 18years. Epidemiological data on sex, age, side, seasonal variation, trauma mechanism, fracture classification (according to AO/OTA), and treatment were analyzed.

Results

3194 patella fractures were analyzed, occurring at a median age of 67 (range 19–100) years. 64% of all patients were female. Most fractures were caused by low-energy trauma, with 70% due to falling from a standing height. 1796 (56%) of the fractures were transverse compared to 845 (26%) vertical fractures. Most fractures (N=2148, 67%) were treated non-operatively. Operative treatment consisted mainly of Tension Band Wiring (TBW) performed in 774 (24%) patients.

Conclusions

Patella fractures mainly occur in elderly women (> 65 years), commonly caused by low-energy trauma. The main treatment is non-operative (67%), except for transverse (AO/OTA C3) fractures. TBW remains the most used operative treatment of choice. These results may help health care providers, researchers and clinicians better understand the panorama of patella fractures in Sweden.

Reoperation and Complication Rates Following Patellar Fracture Repair with Plates: A Retrospective Analysis with Patient-Reported Outcomes at More than 1 Year of Follow-up

Recent work has suggested good clinical and functional results with dorsal surface plating of patellar fractures. The primary outcome measurement of this study was reoperation rates for patellar fractures that had been treated with dorsal plating.

Methods

This work consists of a retrospective review of clinical and functional outcome data following repair of patellar fractures with dorsal plates. We obtained institutional review board approval for this study and conducted a review of 9 consecutive years of our group's trauma practice. We also contacted patients to assess patient-reported outcomes (PROs) after 12 months.

Results

Eighty-five patellar fractures were treated with open reduction and internal fixation (ORIF) via plating over 9 years. Eight (9.41%) of the patients required reoperation. Of the 72 patients with complete follow-up of ≥12 weeks, 3 (4.17%) had nonunion of the fracture site and 4 (5.56%) had loss of reduction of the fracture. The average Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score among our sample was 18.84 (slight symptoms); 72.41% of the patients in our sample had slight or no symptoms at ≥12 months postoperatively.

Conclusions

Our results indicated that plating of comminuted patellar fractures is a safe, viable treatment strategy. The PROs at ≥12 months of follow-up data were promising. Additionally, dorsal plating may allow for early return of function and less postoperative bracing.

Level of Evidence

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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.

Prospective Comparative Study of Fixing Displaced Transverse Patellar Fracture by Tension Band Wiring Versus Cannulated Screws with Wiring

BACKGROUND: Transverse fractures of the patella are important fractures with a wide variety of subtypes, the common incidence in the age group of 20–50 years. Surgical interference aims to achieve a perfect alignment of the joint surface, in addition to rigid fixation of the fracture for early re-habitation and early movement to retain the extensor mechanism of the knee joint. AIM: The aim of this study was to compare the radiological and functional outcomes of the displaced transverse patella fracture in adult patients treated by ORIF using tension band wiring versus cannulated screws with wiring. METHODS: A prospective analytic comparative study was conducted in Al-Kindy Teaching Hospital/Baghdad/Iraq for 18 months from April 1, 2019, to October 1, 2020. It included 32 patients with isolated displaced transverse patellar fracture AO type 34-C1. The patients have undergone operative fixation with two different surgical techniques divided randomly by choosing every other patient into two groups. Group A, the fracture was fixed by cannulated screws with wiring and Group B, the fracture was fixed by two K-wires and with tension band technique. Postoperatively, assessment of the knee function by Lysholm score, the visual analog scale for pain intensity, and active flexion range of movement were measured in degree as primary outcomes, while time to union in weeks assessed radiographically as secondary outcomes. RESULTS: The patients’ age was ranging from 26 to 49 years, with males predominant. Low-energy falls occupying a major part of the mechanism of injury in both groups. Lysholm score was significantly increased after 3, 6, and 12 months compared to that after 1 month in both groups with no statistical differences. The mean visual analog score significantly decreased in Group A after 1 month than that in Group B with no significant change in the other follow-up periods. There were no statistically significant differences in both groups regarding the range of knee movement and the radiographic assessment of fracture healing. CONCLUSION: Both techniques are good and effective with taking into consideration that open reduction and cannulated screws fixation with wiring technique is shown to be associated with lower post-operative pain and a lower frequency of complications mainly surgical site infection.

The clinical outcome of the reduction of the patellar inferior pole fracture with wire cerclage through a generated bone hole, in combination with patellar concentrator: a retrospective comparative study

OBJECTIVE

The patellar inferior pole fracture is typically comminuted. Hence, achieving firm fixation and early activity is highly challenging. In this article, we employed the method of wire cerclage through a generated bone hole to reduce the fracture. Our objective was to compare the clinical efficacy of patellar concentrator alone with a combination of cerclage and patellar concentrator in the treatment of patellar inferior pole fracture.

METHODS

We conducted a retrospective review of patients with patellar inferior pole fractures, who underwent patellar concentrator fixation only (the control group) or cerclage combined with patellar concentrator fixation (the experimental group), performed by a single surgeon, between July 2015 and October 2019. Our analysis included surgical indexes like7 aspects (fracture gap after operation, operation time, intra-operative blood loss, intra-operative number of C-arm fluoroscopies conducted, Insall-Salvati ratio calculated immediately after operation, initial range of motion on the 7th day after operation, and fracture healing time), as well as the Bostman score and complications recorded on 1-, 3-, 6-, and 12-month follow up post operation.

RESULTS

A total of 94 patients with patellar inferior pole fracture and a minimum 1-year follow up were recruited. Following operation, the control group had 33 (71.74%) patients with a fracture gap of 0-2 mm and 13 (28.26%) patients with a fracture gap greater than 2 mm (P = 0.002). Conversely, the experimental group had 46 (95.83%) patients with a fracture gap of 0-2 mm and 2 (4.17%) patients with a fracture gap greater than 2 mm (P = 0.002). Compared to the control group, the experimental group did not experience enhanced operation time or intra-operative blood loss (P = 0.811, P = 0.823). The Insall-Salvati ratio and initial range of motion in the experimental group were larger than the control group (P = 0.037, P = 0.000). Alternately, the number of intra-operative C-arm fluoroscopies conducted and fracture healing time of the experimental group were considerably less than the control group (P = 0.003, P = 0.000). Moreover, at 1-, 3-, 6-, and 12-month follow ups after operation, the Bostman scores of the experimental group were remarkably higher than the control group (P < 0.05). At 12 months post operation, 23 cases (50%) were classified as excellent, 22 cases (47.83%) were good, and 1 case (2.17%) was poor in the control group (P = 0.005). In the meantime, in the experimental group, 38 cases (79.17%) were deemed as excellent and 10 cases (20.83%) were good (P = 0.005). Lastly, complications were detected in 3 cases (6.52%; 1 case of internal fixation loss, 2 cases of hematoma) within the control group, and in 1 case(2.08%; marginal wound necrosis) within the experimental group. There was no wound infection, implant discomfort, or broken fixation in either group.

CONCLUSION

Managing the patellar inferior pole fracture with wire cerclage through a generated bone hole is both simple and effective. Moreover, an additional step of patellar concentrator fixation facilitates early functional exercise, with satisfactory clinical outcome.

A cortical screw based tension band construct for transverse patella fractures: An evolving strategy for addressing common modes of failure

INTRODUCTION

Displaced patella fractures represent a clinical challenge. We evaluate the effectiveness of an alternative fixation construct to address common modes of fixation failure.

METHODS

A retrospective review of 49 patients who underwent fixation via the specific construct at a single institution between 2013 and 2019.

RESULTS

Median follow-up was 52.7 weeks (Mean: 75.4 weeks; SD: 54.9; range: 27-267.7 weeks). Construct failure rate was 6.1% (3/49). This included two mechanical hardware failures, one the result of trauma and the other due to noncompliance.

CONCLUSIONS

The modified construct represents a safe and effective means of treating transverse patella fractures.

LEVEL OF EVIDENCE

Level 4.

Triangular configuration with headless compression screws in the fixation of transverse patellar fracture

A triangular configuration with three parallel cannulated screws is an established treatment for fixing transverse patellar fractures; however, the stability achieved with this approach is slightly lower than that attained with cannulated screws combined with anterior wiring. In the present study, triangular configurations were modified by partially or totally replacing the cannulated screws with headless compression screws (HCSs). Through finite element simulation involving a model of distal femoral, patellar, and proximal tibial fractures, the mechanical stability levels of the modified triangular configurations were compared with that of two cannulated screws combined with anterior wiring. Four triangular screw configurations were developed: three HCSs in a forward and backward triangular configuration, two deep cannulated screws along with one superficial HCS, and two superficial cannulated screws with one deep HCS. Also considered were two parallel cannulated screws (inserted superficially or deeply) combined with anterior wiring. The six approaches were all examined in full knee extension and 45° flexion under physiological loading. The highest stability was obtained with the three HCSs in a backward triangular configuration, as indicated by the least fragment displacement and the smallest fracture gap size. In extension and flexion, this size was smaller than that observed under the use of two deeply placed parallel cannulated screws with anterior wiring by 50.3% (1.53 vs. 0.76 mm) and 43.2% (1.48 vs. 0.84 mm), respectively. Thus, the use of three HCSs in a backward triangular configuration is recommended for the fixation of transverse patellar fractures, especially without the use of anterior wiring.