Patella Fractures: Approach to Treatment

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.

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.

Prior Patellectomy: A Systematic Review and Meta-Analysis Comparing Cruciate-Retaining and Posterior-Stabilized Total Knee Arthroplasty Survivorship and Reported Outcomes

BACKGROUND

In the setting of total knee arthroplasty (TKA), prior patellectomy historically prompted the use of increased constraint implants, specifically posterior-stabilized (PS) designs. However, modern case series have reported similar outcomes utilizing cruciate-retaining (CR) implants. The primary outcome of this study was to compare implant retention rates between these 2 implant designs in prior patellectomy patients. Secondary outcomes included a comparison of patient-reported outcome scores and cause for revision.

METHODS

A comprehensive systematic review was performed using Web of Science, PubMed, and Scopus databases per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Boolean operator search terms included "patellectomy AND (arthroplasty) OR (replacement)." Case reports, review articles, < 2 years of follow-up, and studies in which the implant design could not be ascertained were excluded. An initial screening of titles and abstracts for inclusion was performed, followed by a full manuscript review of eligible articles. Single-data extraction was performed, followed by subsequent statistical analysis.

RESULTS

A total of 9 studies (209 knees) met the inclusion criteria. The average time from patellectomy to TKA was 16.1 years. While all patients had significant improvement in functional outcomes, CR implants displayed proportionally greater improvement in Knee Society Scores compared to PS implants (+108 versus +98%, P ≤ .001). However, there was a significantly greater rate of revision in the CR cohort compared to PS (18.6 versus 2.6%, P = .002).

CONCLUSIONS

Prior patellectomy patients undergoing TKA have significant improvements in patient-reported functional outcomes and high midterm retention rates. While CR implant designs portend a potentially greater improvement in functional outcomes, they also have a greater risk for revision than their PS implant counterparts. However, contemporary implant designs and operative techniques likely render revision rates equivocal between CR and PS implants in postpatellectomy patients.

Patellectomy, an old treatment in patellar fracture which is still alive: A case report

INTRODUCTION

Comminuted patella fractures comprise 55 % of patellar fractures. In spite of advances in internal fixation of patella, patellectomy remains an effective treatment in comminuted fractures. In the shadow of different efficient methods of internal fixation, little attention is paid to patellectomy as an old treatment in patellar fracture which is a treatment option in circumstances like comminuted fractures and osteomyelitis.

PRESENTATION OF CASE

A 54-year-old male presented with complaint of knee pain and limited range of motion. The patient experienced patella fracture four years ago and several sessions of surgery have been performed on his patella including tension band wiring, partial patellectomy, and arthroscopic release. Lastly, pain and severe limited range of motion, convinced us to perform total patellectomy. The result is satisfactory after one year; flexion is up to 90° and no limping or extension lag is observed. The only complaint is mild anterior knee pain.

DISCUSSION

Patella has two important biomechanical functions including linking and displacement. Preserving even a single fragment of the patella substantially improves linking and displacement function of the patella. Total patellectomy is reserved for conditions like failed internal fixation, comminuted fractures, and patellar osteomyelitis. Although function of the knee cannot be thoroughly restored after removing of the patella, total patellectomy can lead to a relative satisfaction in performing activities of daily living.

CONCLUSION

In spite of various types of treatment for patellar fracture, total patellectomy, is still an efficient treatment option in circumstances like comminuted fractures, failed internal fixation, and osteomyelitis.

Retrospective study of patellar fractures and damage of accessory soft tissue based on MRI

BACKGROUND

To better understand the pathophysiological mechanisms of patellar fractures, MRI was utilized to identify the imaging signs of various types of patellar fractures.

METHODS

A retrospective study was performed using MRI images of 52 patients with patellar fractures. Observing the development of patellar and femoral morphology and the imaging manifestations of different fracture types, such as fracture displacement, and damage to accessory ligaments, tendons, and meniscus, type of joint cavity effusion, and damage to surrounding accessory bones were identified.

RESULTS

There were 21 tangential fractures (40.4%), 8 transverse fractures (15.4%), 8 longitudinal fractures (15.4%), 4 oblique fractures (7.7%), and 11 comminuted fractures (21.2%) among the 52 patients with patellar fracture. Tangential fractures begin at a younger age than the other four forms of fractures. When tangential fractures were compared to other types of fractures, medial patellar retinaculum and anterior and posterior cruciate ligament injuries were statistically significant (P< 0.05). The detection rate of trochlear dysplasia, type II and type III patellar was higher in patients with tangential fractures than in other fractures.

CONCLUSIONS

Tangential fractures are less common to cause anterior and posterior cruciate ligament injuries than other types of fractures, but they are more likely to cause medial patellar retinaculum injuries.

The patient with a painful knee

Knee pain encompasses a wide array of differential diagnoses and can often pose a diagnostic challenge, as it can have traumatic or non-traumatic causes. A good clinical history, assessment and anatomical knowledge gives a strong foundation to narrow down the diagnosis, and understanding the correct imaging modality and findings further informs correct and timely management. This article reviews various disease processes including fractures, inflammatory, infective and neoplastic causes, and discusses the assessment and various imaging modalities to aid diagnosis in both primary and secondary care.

Atraumatic Bilateral Patella Fracture in Middle-Aged Female: A Rare Case Report

The patella is the largest sesamoid bone in the body and an important structure of the extensor apparatus which is under undue stress during flexion and extension of the knee. Bilateral fracture of the patella without trauma is a very rare event and may be multifactorial without a single cause. A repetitive stress reaction in a previously predisposed bone can be an important cause. We report a case of a 45-year-old female with a nontraumatic bilateral transverse patella fracture with loss of extensor mechanism. A stable surgical fixation for such a displaced fracture with a good rehabilitation program can lead to a good functional outcome.

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.

Osteochondral impression fracture of the patella after sports collision injury

This article reports a case of a teenager who suffered a frontal collision sports injury. Computed Tomography (CT) revealed a fracture of the inferior pole of the patella without obvious displacement and retro patellar cortical impression with 5 mm step off. Surgical intervention was performed using β-tricalcium phosphate (β-TCP) and 3.0 cannulated screw fixation.At 3-month follow-up, the wound showed good healing. No pain was observed. The patient was able to flex up to 100° with full extension. There were no signs of hydrops with full stability of the knee.Good postoperative results can be obtained in osteochondral impression fractures of the patella using surgical intervention to elevate the osteochondral fragment, graft it with β-TCP and raft it with 3.0 cannulated screws.

A minimally invasive bipolar surgical approach for the treatment of patellar fracture using the tension-band wiring technique

Objective

Minimally invasive surgical techniques are becoming increasingly popular for the treatment of traumatic injuries. Although some minimally invasive techniques in the management of patellar fractures have been reported, the limited exposure in such methods may cause technical difficulties during surgery and restrict their wide application. In this context, this study aims to introduce a bipolar incision and assess the clinical outcomes of patellar fractures treated via this type of incision.

Materials and methods

Patients who suffered patellar fractures and who received surgical treatment via bipolar incision between 2018 and 2020 in our hospital were retrospectively reviewed and included in this study. The clinical and radiological records of all patients were reviewed. A classification of the fractures was done and intraoperative parameters, Visual Analog Scale (VAS) score, knee range of motion, and the Hospital for Special Surgery (HSS) knee score of the patients were evaluated and summarized.

Results

The study included 19 patients who met the inclusion criteria. All patellar fractures were operated through the minimally invasive bipolar surgical approach. The mean time of operation was 69.0 ± 8.5 min. The mean time to union was 12.8 ± 2.1 weeks. The average total knee range of motion was 131.8 ± 4.4°, and the average HSS score was 97.1 ± 2.6 at 1-year post-operation. No surgical-related complications were observed.

Conclusions

The knee functional outcomes were favorable when patellar fractures were treated through the minimally invasive bipolar incision method. This bipolar surgical approach was found to be a feasible method for treating patellar fractures.

[Progress in the surgical treatment of the patellar fracture]

OBJECTIVE

To review research progress of surgical treatment of patellar fractures.

METHODS

The domestic and foreign literature about patellar fracture treatment in recent years was extensively consulted, and the advantages, disadvantages, and indications of various surgical treatments were summarized.

RESULTS

The patella plays an important role in knee flexion and extension activities, and the fracture significantly affects the patient's quality of life. At present, the surgical methods include open reduction and internal fixation and patella resection. The internal fixation methods include ring/binding patella fixation, tension band wiring and improved technology, tension band wiring combined with other methods, screw fixation (including absorbable screws), steel plate fixation, and patella fixator fixation. Each surgical method has different indications, advantages, and disadvantages. Choosing an appropriate treatment plan plays a crucial role in clinical prognosis.

CONCLUSION

There are many surgical treatments for patellar fractures. In order to improve the effectiveness and reduce postoperative complications, it is necessary to choose the most appropriate treatment strategy for the type of fracture.

Open Reduction and Internal Fixation of Patella Fracture With Contoured Dorsal Plating

In this article, we present a novel patella fixation technique using a low-profile highly contoured dorsal mini-fragment locking plate. This procedure is ideally indicated in patients with fracture patterns that are transverse without significant comminution. Long-term clinical studies are being performed to evaluate the effectiveness of this surgical technique.

Patellar Fracture Fixation With Cannulated Compression Screws and FiberTape Cerclage

Transverse patella fractures with loss of knee extensor mechanism function are a common orthopaedic injury requiring operative fixation. Current accepted surgical options for noncomminuted transverse fractures include open reduction with tension band wiring. Although these procedures result in good clinical outcomes and fracture healing, symptomatic hardware from the historically used metal implants is very common. The purpose of this Technical Note is to describe a technique for treatment of transverse patellar fractures using cannulated compression screws with tensioned high-resistance suture tape functioning as the tension band. This technique provides effective, reproducible fracture fixation while minimizing symptomatic hardware, failure, and reoperation.