Comparison of a technique using a new percutaneous osteosynthesis device with conventional open surgery for displaced patella fractures in a randomized controlled trial

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.

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.

Comparison of minimally invasive percutaneous fixation and open reduction internal fixation for patella fractures: a meta-analysis

BACKGROUND

Open reduction internal fixation (ORIF) has long been the conventional procedure for managing displaced patella fracture. This surgical approach has certain drawbacks, which might affect clinical outcomes and patient prognosis. Minimally invasive percutaneous fixation (MIPF) was proposed to overcome these disadvantages. Few in-depth investigations have been performed to determine the superiority of MIPF over ORIF. The aim of this study was to compare the efficacies of MIPF and ORIF for patella fractures.

METHODS

The PubMed, Cochrane Library, Embase, and Scopus databases were searched for relevant studies from November 26 to December 17, 2020. Non-English publications and pediatric orthopedic articles were excluded. Statistical analysis was performed using Review Manager, version 5.4, with mean differences (MDs), standardized mean differences (SMDs), odds ratios (ORs), and respective 95% confidence intervals (CIs) calculated using a random effects model. The primary outcomes were the pain score, knee range of motion, and joint functionality. The secondary outcomes were the surgical time, complications, and implant removal rate.

RESULTS

Six articles with a total of 304 patients were included in the meta-analysis. Pooled analysis revealed that patients with MIPF had a significantly reduced pain score (MD = - 1.30, 95% CI = - 1.77 to -0.82; p < 0.00001) and increased knee extension angles (MD = 0.72, 95% CI = 0.18 to 1.25; p = 0.009) at 3-month follow-up. Furthermore, knee flexion angles (MD = 8.96, 95% CI = 5.81 to 12.1; p < 0.00001) and joint functionality (SMD = 0.54, 95% CI = 0.21 to 0.86; p = 0.001) had statistically improved at 2 years. However, no difference was observed between MIPF and ORIF with regard to the surgical time. The risk of complications (OR = 0.10, 95% CI = 0.05 to 0.18; p < 0.00001) and implant removal rate (OR = 0.20, 95% CI = 0.07 to 0.57; p = 0.003) were significantly lower with MIPF than with ORIF.

CONCLUSIONS

MIPF is more favorable than ORIF in terms of the pain score, knee range of motion, joint functionality, complications, and implant removal rate. Thus, it can be adopted as an alternative to ORIF.

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

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

Treatment of displaced fractures of the patella: Tension band wiring technique with the one-end or both-ends K-wire bending fixation method

PURPOSE

Tension band wiring technique has been widely used for treating patellar fracture. Conventional techniques are associated with some complications and several modifications have been introduced to increase stabilization. The purpose of this study was to compare two different fixation techniques, the one-end and both-ends Kirschner wire bending fixation methods.

METHODS

We retrospectively reviewed patient data from 2013 to 2017, including the age, sex, body height, body weight, BMI, lesion of injury, trauma mechanism, fracture displacement and classification, type of fixation, fracture healing duration, length of follow-up, clinical results and complications. The surgical outcome was assessed using the pain score (VAS), Lysholm knee score, and knee joint ROM. Plain radiographs were used to evaluate radiographic outcomes and assess the fracture union duration and hardware complications. We performed statistical analysis to compare these two different fixation techniques.

RESULTS

There were no significant differences between the two groups in terms of demographic data, fracture healing duration, level of the K-wires, distance between the K-wires, or length of the K-wires over the patella length (all p > 0.05). There were significant differences in the VAS score, K-wire migration, flexion degree, ROM, and Lysholm score (all p < 0.001) between the two different fixation methods.

CONCLUSION

The both-ends K-wire bending fixation method has a lower complication rate and results in a better clinical outcome than the one-end K-wire bending fixation method. This revised technique can effectively control both ends of the K-wires, thus eliminating the possibility of K-wire migration and improving the fixation stability.

Interventions for treating fractures of the patella in adults

BACKGROUND

Fractures of the patella (kneecap) account for around 1% of all human fractures. The treatment of these fractures can be surgical or conservative (such as immobilisation with a cast or brace). There are many different surgical and conservative interventions for treating fractures of the patella in adults. This is an update of a Cochrane Review first published in 2015.

OBJECTIVES

To assess the effects (benefits and harms) of interventions (surgical and conservative) for treating fractures of the patella in adults.

SEARCH METHODS

We searched CENTRAL (2020, Issue 1), MEDLINE, Embase, LILACS, trial registers and references lists of articles to January 2020.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) or quasi-RCTs that evaluated any surgical or conservative intervention for treating adults with fractures of the patella. The primary outcomes were patient-rated knee function, knee pain and major adverse outcomes.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected eligible trials, assessed risk of bias and cross-checked data extraction. Where appropriate, we pooled results of comparable trials.

MAIN RESULTS

We included 11 small trials involving 564 adults (aged 16 to 76 years) with patella fractures. There were 340 men and 212 women; the gender of 12 participants was not reported. Seven trials were conducted in China and one each in Finland, Mexico, Pakistan and Turkey. All 11 trials compared different surgical interventions for patella fractures. All trials had design flaws, such as lack of assessor blinding, which put them at high risk of bias, potentially limiting the reliability of their findings. No trial reported on health-related quality of life, return to previous activity or cosmetic appearance. The trials tested one of seven comparisons. In the following, we report those of the main outcomes for which evidence was available for the three most important comparisons. Four trials (174 participants) compared percutaneous osteosynthesis versus open surgery. Very low-quality evidence means that we are uncertain of the findings of no clinically important difference between the two interventions in patient-rated knee function at 12 months (1 study, 50 participants) or in knee pain at intermediate-term follow-up at eight weeks to three months. Furthermore, very low-quality evidence means we are uncertain whether, compared with open surgery, percutaneous fixation surgery reduces the incidence of major adverse outcomes, such as loss of reduction and hardware complications, or results in better observer-rated knee function scores. Two trials (112 participants) compared cable pin system (open or percutaneous surgery) versus tension band technique. The very low-quality evidence means we are uncertain of the findings at one year in favour of the cable pin system of slightly better patient-rated knee function, fewer adverse events and slightly better observer-rated measures of knee function. There was very low-quality evidence of little clinically important between-group difference in knee pain at three months. Very low-quality evidence from two small trials (47 participants) means that we are uncertain of the findings of little difference between biodegradable versus metallic implants at two-year follow-up in the numbers of participants with occasional knee pain, incurring adverse events or with reduced knee motion. There was very low-quality and incomplete evidence from single trials for four other comparisons. This means we are uncertain of the results of one trial (28 participants) that compared patellectomy with advancement of vastus medialis obliquus surgery with simple patellectomy; of one quasi-RCT (56 participants) that compared a new intraoperative reduction technique compared with a standard technique; of one quasi-RCT (65 participants) that compared a modified tension band technique versus the conventional AO tension band wiring (TBW) technique; and of one trial (57 participants) that compared adjustable patella claws and absorbable suture versus Kirschner wire tension band.

AUTHORS' CONCLUSIONS

There is very limited evidence from nine RCTs and two quasi-RCTs on the relative effects of different surgical interventions for treating fractures of the patella in adults. There is no evidence from trials evaluating the relative effects of surgical versus conservative treatment or different types of conservative interventions. Given the very low-quality evidence, we are uncertain whether methods of percutaneous osteosynthesis give better results than conventional open surgery; whether cable pin system (open or percutaneous surgery) gives better results than the tension band technique; and whether biodegradable implants are better than metallic implants for displaced patellar fractures. Further randomised trials are needed, but, to optimise research effort, these should be preceded by research that aims to identify priority questions.

Patella Distal Pole Fracture Treated Using Ipsilateral Hamstring Autograft Augmentation and No Additional Hardware

Patellar lower-pole fractures occur in relatively young patients after eccentric contraction of the quadriceps or direct trauma. Early diagnosis and adequate treatment lead to excellent outcomes and prevent tendon retraction and scarring. The aim of surgical treatment is to restore articular congruence and reestablish the extensor mechanism of the knee. All surgical treatments (sutures and tension band wiring, separate vertical wiring or augmented with Krackow sutures, wiring through screws, basket plate, hook plate) use additional hardware. We propose a hardware-free technique using ipsilateral hamstring augmentation.

Minimally invasive osteosynthesis technique in the treatment of transverse patellar fractures in the elderly

BACKGROUND

This prospective study aims to describe our experience in the management of transverse patellar fractures in elderly patients with minimally invasive osteosynthesis technique (MIOT), at 12-months follow-up.

METHODS

Patients older than 60, with transverse patellar fracture, type 34-C1 according to the AO/OTA classification system, referred to our trauma centre, between January 2014 and December 2017 were prospectively recruited. All the patients were managed using MIOT surgical procedure and underwent a clinical and radiological follow-up at 2 weeks, 6 weeks and at 3, 6, 12 and 15 months postoperatively. The clinical evaluation was performed using the Lysholm Knee Scoring System (LKSS) and the Visual Analogue Scale (VAS) for pain. The hardware removal was planned at 12-months follow-up. The paired t-test was performed. The test was two-tailed with a confidence level of 5%.

RESULTS

61 patients were recruited. The mean VAS was significantly lower in MIOT group until the 3-months follow-up (p = 0.001). ROM in flexion and LKSS score were significantly better in MIOT-group at all follow-ups, whereas ROM in extension showed no differences, between the two groups, starting from the 6-months follow-up. In the open surgery group, a significantly higher rate of delayed wound healing (p = 0.014), broken wires (p = 0.001) and non-cosmetic scar (p = 0.0221) was observed.

CONCLUSIONS

This prospective study shows that MIOT is a safe option for treatment of patellar transverse fractures in elderly patients, since it reduces the intra-operative blood loss, shortens the operating time, and is endowed with lower rates of postoperative complications.

Predicting the risk of sarcopenia in elderly patients with patellar fracture: development and assessment of a new predictive nomogram

Purpose

To develop a risk prediction model for postoperative sarcopenia in elderly patients with patellar fractures in China.

Patients and methods

We conducted a community survey of patients aged ≥55 years who underwent surgery for patellar fractures between January 2013 and October 2018, through telephone interviews, community visits, and outpatient follow-up. We established a predictive model for assessing the risk of sarcopenia after patellar fractures. We developed the prediction model by combining multivariate logistic regression analysis with the least absolute shrinkage model and selection operator regression (lasso analysis) as well as the Support Vector Machine (SVM) algorithm. The predictive quality and clinical utility of the predictive model were determined using C-index, calibration plots, and decision curve analysis. We also conducted internal sampling methods for qualitative assessment.

Result

We recruited 137 participants (53 male; mean age, 65.7 years). Various risk factors were assessed, and low body mass index and advanced age were identified as the most important risk factor (P < 0.05). The prediction rate of the model was good (C-index: 0.88; 95% CI [0.80552–0.95448]), with a satisfactory correction effect. The C index is 0.97 in the validation queue and 0.894 in the entire cohort. Decision curve analysis suggested good clinical practicability.

Conclusion

Our prediction model shows promise as a cost-effective tool for predicting the risk of postoperative sarcopenia in elderly patients based on the following: advanced age, low body mass index, diabetes, less outdoor exercise, no postoperative rehabilitation, different surgical methods, diabetes, open fracture, and removal of internal fixation.

Comparison of a minimally invasive surgical technique with open surgery for transverse patella fractures

The current study aimed to compare a minimally invasive surgical technique with open surgery for the treatment of transverse patella fractures. A total of 38 patients with displaced transverse fractures of the patella were included in the current prospective study. A total 21 of them were treated with a minimally invasive surgical (MIS) technique and the other 17 patients had open surgery (OS) when using the Cable Pin System. Postoperative comparisons were based on radiographs, the visual analog scale (VAS) of pain, their ranges of motion and the Bostman grading scale. Compared with the OS group, the VAS score for pain was significantly lower and the angle of active flexion was better in the MIS group at 4 and 8 weeks. The angle of active extension at 4 weeks and the Bostman score at 8 weeks after surgery were better in the MIS group, although the differences became non-significant at 8 weeks and 12 months. In conclusion, the MIS technique for transverse patella fractures provided better clinical results and the knees functioned with less pain when compared with the OS group in the early period following surgery. MIS could be an adequate alternative in the treatment of transverse patella fractures.

Outcomes after locked plating of displaced patella fractures: a prospective case series

PURPOSE

Tension band wiring remains a common treatment for patella fractures, but complication rates are high, with unsatisfactory results. The purpose of this observation study was to evaluate clinical results and complication rates of a novel patella locking plate fixation.

METHODS

Twenty patients (mean age, 59.2 ± 18 years) with displaced patella fractures were prospectively enrolled. Range of motion, knee scores (Tegner, Lysholm, Kujala), complications, and revision surgeries were assessed six weeks, six months, 12 months, and 24 months after surgery. Results were compared to the situation before trauma in regards to the time of follow-up using a paired sample t test.

RESULTS

According to the OTA classification, the fractures were classified as follows: one A1, four C1, six C2, and nine C3. Range of motion improved from 121° after six weeks to 140°, 141°, and 143° within the follow-up period. While the Tegner, Lysholm, and Kujala scores were 4.1/97/97, respectively, before trauma, they improved from 2.6/80/89 to 3.6/94/89, 3.7/95/94, and 4.1/97/97 within the follow-up period. Three patients had a complication (15%): one fracture dislocation, one reactive bursitis, and one renewed fracture. Four patients reported discomfort or anterior knee pain especially when kneeling on the implant.

CONCLUSIONS

The patella locking plate is a safe and effective treatment for patella fractures, including comminuted fractures. Function can be restored within six months after surgery, and the complication rate is low. Nonetheless, the implant can cause discomfort or anterior knee pain especially when kneeling, which can necessitate an implant removal.

[Plate osteosynthesis after patellar fracture - the technique and initial results of a prospective study]

BACKGROUND

Tension band wiring after patellar fractures is related to a high number of implant-related complications (22-53 %). Revision surgery is necessary in 10-55 % of patients mostly with unsatisfactory results. The patella plate is an alternative treatment with the advantages of locked plating. The purpose of this study was to evaluate the first clinical prospective results and complications of this new implant.

MATERIALS AND METHODS

Between April 2013 and May 2015 all patients that were treated with locked plating for patella fractures were included in this prospective study. Patients were followed-up clinically after six weeks and six months.

RESULTS

Included in this study were 17 patients, 6 women and 11 men, with a mean age of 58 years (19-87). The knee range of motion was 120° after 6 weeks and improved to 138° after 6 months, corresponding to 84 % and 97 % of the range of motion of the healthy opposite knee. The Tegner activity scale increased from 2,5 to 3,5 (initial value: 4), the Lysholm score increased from 78 to 92 points (initial value: 97) and the Kujala score increased from 72 to 88 points (initial value: 96). Two complications occurred: one patient had a reactive bursitis prepatellaris and one patient sustained a loss of reduction.

CONCLUSION

Locked plating of patella fractures is a reliable alternative treatment with good functional outcomes and low complication rates.

Treatment of Patella Fractures

Patella fractures comprise 1% of all fractures. Treatment options vary based on fracture displacement, classification, and patient factors. Traditionally, nonoperative treatment has been reserved for nondisplaced fractures. Many operative treatments are available with differing indications and levels of success. Tension band constructs have been the most commonly employed approach to fixation, with cerclage wiring for comminuted fractures. Recently, plate fixation of patella fractures has become more popular. Plating constructs offer a low-profile design with stable fixation, allowing for earlier mobilization and potentially improved functional outcomes. Data regarding the long-term outcomes of plating techniques are limited, and further studies are needed. [Orthopedics. 2018; 41(6):e747-e755.].

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

BACKGROUND

Displaced transverse patellar fractures require open reduction and internal fixation. State-of-the-art stabilization techniques are tension band wiring (TBW) using Kirschner wires or cannulated screws. These techniques are associated with high rates of secondary fracture displacement, implant migration, implant prominence, wound-healing disturbances, and the need for implant removal. Recently, a locked intraosseous patellar nail prototype was developed. The aim of the present study was to investigate the biomechanical performance of this nail compared with TBW using cannulated screws.

METHODS

Seven paired fresh-frozen human cadaveric knees were stripped of all soft tissues except the extensor apparatus. A transverse osteotomy was created to simulate an OTA/AO type 34-C1 transverse patellar fracture. The specimen pairs were randomly assigned to be fixed with TBW using cannulated screws or with the new intraosseous nail. Each specimen was cyclically tested for 5,000 cycles by pulling on the quadriceps tendon and simulating active knee extension and passive knee flexion within the range from 90° of flexion to full knee extension. Anterior and articular margin displacement of the fracture as well as interfragmentary rotation around the mediolateral axis were investigated with optical motion tracking after 100, 500, 1,000, 2,500, and 5,000 test cycles.

RESULTS

Within the respective 5 testing-cycle time points evaluated, the articular margin displaced on average 68%, 60%, 72%, 76%, and 81% less after intraosseous nailing compared with TBW. Whereas the difference remained nonsignificant after 100 and 500 cycles (p ≥ 0.116), a trend toward significance was observed after 1,000 cycles (p = 0.063), which became significant after 2,500 and 5,000 cycles (p ≤ 0.043).

CONCLUSIONS

From a biomechanical point of view, the locked intraosseous patellar nail may be an alternative to TBW using cannulated screws because of the higher interfragmentary stability provided at the articular fracture site.

CLINICAL RELEVANCE

A locked patellar nail for transverse patellar fractures achieved a stable osteosynthetic construct that may reduce hardware-associated complications because of its intraosseous positioning.

Fixed angle plate fixation of comminuted patellar fractures

INTRODUCTION

Comminuted patella fractures are uncommon and difficult fractures to manage. Multiple treatment modalities have been suggested, with little clinical data to support practice. Recent biomechanical and technical investigations have described successful plate fixation of comminuted patella fractures. The purpose of this study was to evaluate radiographic, clinical and functional outcome of comminuted patella fractures treated with a fixed angle locking plates. We believe stable fixation, which results in successful fracture union and functional recovery, can be achieved with this technique.

MATERIALS AND METHODS

A retrospective review was performed at a single regional academic Level 1 trauma hospital. All comminuted patella fractures treated with a fixed angle locking plate (AO/OTA 34C2 and C3) over a six-year period were evaluated. Thirty-six patients were identified. Average length of follow up was 154 weeks (range 12-297 weeks). Twenty patients were available for functional outcome scoring. Primary outcome measures were: Knee Outcome Score (KOS), Lower Extremity Functional Scale (LES) and goniometer measured knee range of motion. Secondary outcomes evaluated the need for additional screw or cerclage fixation, reoperation for any reason, bothersome hardware, infection and nonunion.

RESULTS

Average KOS = 57.2 (20-74), average LES = 58.9 (15-80). Median extension = 0° (full extension), median flexion = 130°. Supplemental screws were used in 17/36 cases; cerclage used in 2/36 cases. Hardware irritation was noted in 4/20 patients, no patient requested elective hardware removal, one patient had failure of fixation and no nonunions were identified.

CONCLUSION

Fixed angle plate stabilization of comminuted patella fractures is a viable technique for fracture fixation. Good to excellent return of knee function and low complication rates, including need for hardware removal, can be expected.

Definition of infection after fracture fixation: A systematic review of randomized controlled trials to evaluate current practice

INTRODUCTION

One of the most challenging musculoskeletal complications in modern trauma surgery is infection after fracture fixation (IAFF). Although infections are clinically obvious in many cases, a clear definition of the term IAFF is crucial, not only for the evaluation of published research data but also for the establishment of uniform treatment concepts. The aim of this systematic review was to identify the definitions used in the scientific literature to describe infectious complications after internal fixation of fractures. The hypothesis of this study was that the majority of fracture-related literature do not define IAFF.

MATERIAL AND METHODS

A comprehensive search was performed in Embase, Cochrane, Google Scholar, Medline (OvidSP), PubMed publisher and Web-of-Science for randomized controlled trials (RCTs) on fracture fixation. Data were collected on the definition of infectious complications after fracture fixation used in each study. Study selection was accomplished through two phases. During the first phase, titles and abstracts were reviewed for relevance, and the full texts of relevant articles were obtained. During the second phase, full-text articles were reviewed. All definitions were literally extracted and collected in a database. Then, a classification was designed to rate the quality of the description of IAFF.

RESULTS

A total of 100 RCT's were identified in the search. Of 100 studies, only two (2%) cited a validated definition to describe IAFF. In 28 (28%) RCTs, the authors used a self-designed definition. In the other 70 RCTs, (70%) there was no description of a definition in the Methods section, although all of the articles described infections as an outcome parameter in the Results section.

CONCLUSION

This systematic review shows that IAFF is not defined in a large majority of the fracture-related literature. To our knowledge, this is the first study conducted with the objective to explore this important issue. The lack of a consensus definition remains a problem in current orthopedic trauma research and treatment and this void should be addressed in the near future.

Biomechanical comparison of pin and tension-band wire fixation with a prototype locking plate fixation in a transverse canine patellar fracture model

Objective: To compare a locking plate (LP) with pin and tension-band wire (pin/TBW) for fixation of mid-patellar transverse fractures.

Materials and methods: Cadaveric canine stifle joints from 10 adult mixed breed dogs (23–36 kg) were used. Mid-patellar transverse osteotomies were randomly stabilized (in pairs) with either pin/TBW or a prototype LP. Cyclic loads (1 Hz, 500 cycles) at 100% body weight (90°-135° stifle joint extension), were applied. Survival or failure of constructs was defined as <2 mm fracture gap distraction at 500 cycles, or ≥ 2 mm fracture gap distraction at the number of cycles sustained, respectively. Number of cycles at failure and distraction gap were compared with a paired Student’s t-test, and a survival analysis performed with a Mantel-Cox test. All constructs that survived cyclic testing were tested in single cycle load to failure (1.0 mm/sec; 110° stifle joint extension); yield strength was compared with a Wilcoxon rank sum test. Significance was set at p <0.05.

Results: All 10/10 LP and three out of 10 pin/ TBW fixations survived cyclic testing. Survival analysis, number of cycles at failure, and distraction gap all were significantly different between the two groups (p = 0.0011, p = 0.0013, and p <0.0001, respectively). Construct yield strength was not significantly different (p = 0.1273).

Conclusions: The failure mode with pin/TBW was consistently similar to failures observed clinically. The LP demonstrated consistent, reliable and stable fixation.

This work was performed at the Biomechanics Orthopedic Research Laboratory, Cummings School of Veterinary Medicine at Tufts University, North Grafton, MA, USA.

Arthroscopically assisted fixation is a reliable option for patellar fractures: A literature review

Proper reduction and stable fixation of articular fractures is essential for an early recovery and to avoid late complications. Arthroscopically assisted techniques for minimally invasive fixation have been introduced to reduce local morbidity and improve anatomic reduction of the fragments. However up to date no clear indications for surgery have been given. In addition, the precise rates of functional outcomes and complications are controversial. The hypothesis was the systematic analysis of the available literature would provide precise indications, outcomes and complications of arthroscopically assisted techniques for patellar fracture fixation. A comprehensive literature review was performed using the keywords "patellar fracture", "arthroscopy" with no limit regarding the year of publication. All the selected articles were in English language and were evaluated with the Coleman score by three independent surgeons. The interclass correlation coefficient between the three examiners was calculated. Six full text articles were retrieved. The initial cohort included 60 patients with a displaced transverse fracture in the majority of the cases. At an average FU of 27.2 months the Lysholm score was 91.3. The rate of complication was 7%; Average Coleman score for the three observers was 55.8±6.5 with an ICC of 0.89, indicating adequate inter-rater agreement. Arthroscopically assisted techniques for minimally invasive fixation of patellar fractures represent a reliable option. The positive clinical outcomes and low rates of complications must be confirmed with further studies including larger series and longer FU.

LEVEL OF EVIDENCE

Level IV, systematic review of retrospective series.

Biomechanical evaluation of the tension band wiring principle. A comparison between two different techniques for transverse patella fracture fixation

PURPOSE

The aim of this study was to investigate the validity of the dynamic compression principle of tension band wiring in two techniques for patella fracture treatment.

METHODS

Twelve human cadaveric knees with simulated transverse patella fractures were assigned to two groups for treatment with tension band wiring using either Kirschner (K-) wires or cannulated screws. Biomechanical testing was performed over three knee movement cycles between 90° flexion and 0° full extension. Pressure distribution in the fracture gap and fracture site displacement were evaluated at the 3^rd cycle in 15° steps, namely 90°-75°-60°-45°-30°-15°-0° extension phase and 0°-15°-30°-45°-60°-75°-90° flexion phase.

RESULTS

Mean anterior / posterior interfragmentary pressure in the groups with K-wires and cannulated screws ranged within 0.16-0.40MPa / 0.12-0.35MPa and 0.37-0.59MPa / 0.10-0.30MPa, respectively. These changes remained non-significant for both groups and loading phases (P≥0.171). Mean anterior / posterior fracture site displacement for K-wires and cannulated screws ranged within -0.01-0.53mm / 0.11-0.74mm and 0.11-0.55mm / -0.10-0.50mm, respectively. Anterior displacement remained without significant changes for both groups and loading phases (P≥0.112). However, posterior displacement underwent a significant increase in the course of knee extension for K-wires (P≤0.047), but not for cannulated screws (P≥0.202). Significantly smaller displacement at the posterior fracture site was detected in the group with cannulated screws compared to K-wires at 60° and 75° extension phase (P≤0.017), as well as at 45°, 60° and 75° flexion phase (P≤0.018). The critical value of 2mm displacement at the posterior fracture site was not reached for any specimen and fixation technique. Knee extension was accompanied by synchronous increase in quadriceps pulling force.

CONCLUSIONS

Tension band wiring fulfills from a biomechanical perspective the requirements for sufficient stability of transverse patella fracture fixation. It should, however, rather be considered as a static fixation principle than a dynamic one. Tension band wiring with cannulated screws was found advantageous over Kirschner wires in terms of interfragmentary movements at the posterior fracture site.

Comminuted Patella Fracture in Elderly Patients: A Systematic Review and Case Report

Objectives:

To review comminuted patella fracture in the elderly patients and examine the surgical options to avoid complications such as fixation failure and poor functional outcome. To provide an example of mesh augmentation in comminuted patella fracture in the elderly patients.

Data Sources:

A literature review was conducted by the authors independently using Ovid, Medline, Cochrane, PubMed, and Clinical Key in English. We aimed to review data on patients older than 65 with comminuted patella fracture. Search conducted between July and December 2015.

Study Selection:

Search terms included patella fracture, elderly, and fixation failure. Abstracts were included if they were a case report, cohort series, or randomized control trial. Further inclusion criteria were that they were available in full text and included patient age(s), operative details, follow-up, and outcome discussion.

Data Extraction:

Each study was assessed according to its level of evidence, number of patients, age of patients, fracture patterns described, complications of treatment, and results summarized.

Data Synthesis:

Paucity of data and heterogeneity of studies limited statistical analysis. Data are presented as a review table with the key points summarized.

Conclusion:

In patella fracture, age >65 years and comminuted fracture pattern are predictors of increased fixation failure and postoperative stiffness, warranting special consideration. There is a trend toward improved functional outcomes when augmented fixation using mesh or plates is used in this group. Further level 1 studies are required to compare and validate new treatment options and compared them to standard surgical technique of tension band wire construct.

Clinical results of treatment using a modified K-wire tension band versus a cannulated screw tension band in transverse patella fractures: A strobe-compliant retrospective observational study

It was a retrospective case-control study. The aim of this study was to explore the clinical efficacy and complication of treatment using a modified Kirschner wire tension band (MKTB) or a cannulated screw tension band (CSTB) in transverse patellar fractures.In total, 55 patients with transverse patellar fractures were retrospectively reviewed and divided into 2 groups according to the surgical technique: 29 patients were in the MKTB group and 26 patients in the CSTB group. B[Latin Small Letter o with Caron]stman's clinical grading scale, including range of movement (ROM), pain, ability to work, atrophy of quadriceps femoris, assistance in walking, effusion, giving way, and stair-climbing, was used to evaluate the clinical results. Complications including painful hardware, implant loosening or breakage, and bone nonunion were also assessed.Both groups were evaluated at the final follow-up before removing implant in the MKTB group. The B[Latin Small Letter o with Caron]stman's score of ROM, pain, atrophy of quadriceps femoris, and effusion were all higher in the CSTB group than in the MKTB group (P < 0.05). Twelve patients in the MKTB group underwent implant removal, and the score of ROM, pain, and effusion were higher than before removing implant (P < 0.05), but there was no difference compared to the CSTB group (P > 0.05). Seventeen patients achieved excellent results, 9 had good results, and 3 reported fair results in the MKTB group; the CSTB group had excellent results in 22 patients and good results in 4 patients, showing a significant difference in the excellent rate between the 2 groups (P = 0.021). Total B[Latin Small Letter o with Caron]stman scores in the MKTB and CSTB groups (26.96 ± 4.47 and 29.42 ± 1.47, respectively) were significantly different (P = 0.01). Total scores in the MKTB group after removing implant were higher than those before removing implant (P = 0.001), and similar to those in the CSTB group (P = 0.224). Eleven patients in the MKTB group reported painful hardware, including 4 cases of implant loosening.CSTB achieves better clinical results than MKTB, meanwhile avoiding the problems of painful hardware and implant loosening. Functional limitation caused by hardware pain was commonly seen in the MKTB group, and removing implant after fracture healing improved knee function.

Adult native knee extensor mechanism ruptures

Extensor mechanism rupture is a serious event requiring prompt diagnosis and treatment. Patella fractures are reportedly six times more frequent than soft tissue injuries such as quadriceps or patella tendon ruptures. Classically quadriceps and patella tendon ruptures are seen more in males, with those over 40 predominantly suffering from quadriceps tendon ruptures, often associated with an underlying condition, whereas patella tendon ruptures are mostly associated with sport injuries and are commonly seen in the under 40s. Almost all types of extensor mechanism ruptures benefit from early management which typically involves surgery. Diagnosis can be deemed easy to make by demonstrating inability to actively extend the knee, this however can be easily overlooked and missed in a busy emergency department leading to a late diagnosis and necessitating more complex surgery. Earlier surgical intervention and rehabilitation tend to produce improved outcomes.

Comparison of the outcomes of cannulated screws vs. modified tension band wiring fixation techniques in the management of mildly displaced patellar fractures

BACKGROUND

K wire fixation with tension band wiring has conventionally been used for the open reduction and internal fixation of the patella. However, it suffers from distinct disadvantages such as implant irritation, need for open reduction, incidence of palpable implants, and need for subsequent implant removal. A smaller incision with percutaneous fixation may be an alternative to this established conventional technique. Thus, the purpose of this trial was to compare the treatment outcomes of patients with mildly displaced patellar fractures treated with closed reduction and percutaneous cannulated screw fixation (CRCF) as compared to open reduction and tension band wiring fixation (ORTF). Specifically, we aimed to determine whether cannulated screw fixation was associated with improved clinical outcomes at 12 months as measured using the Lysholm score, pain scores, degree of flexion, range of motion, time to radiographic union, radiographic outcomes, and complication rates.

METHODS

Sixty-three patients with transverse patellar fractures displaced less than 8 mm were included in this prospective, randomized, controlled trial, with 52 patients in the final data analysis. Thirty-two patients were operatively treated by CRCF with either two or three cannulated screws. Thirty-one patients were operatively treated by conventional ORTF using the modified tension band technique. At postoperative intervals of 3, 6, and 12 months, knee function was evaluated using the Lysholm score, pain was assessed using the visual analog scale (VAS) score, and active knee extensions and flexion were measured in degrees by goniometry.

RESULTS

The CRCF group had average Lysholm scores of 84.4 ± 5.8, 86.7 ± 6.4, and 93.2 ± 5.3 after 3, 6, and 12 months, respectively, which were significantly greater than those of the ORTF group (79.0 ± 5.3, p = 0.001; 81.5 ± 4.6, p = 0.002; and 89.8 ± 6.2, p = 0.039, respectively). Lower pain and squatting scores were the main reasons for the poorer Lysholm scores in the ORTF group. The VAS scores showed that the CRCF group had lower pain scores and better flexion and total range of motion (ROM) compared with the ORTF group after 3 and 6 months, although both groups had similar outcomes after 12 months. The mean fracture healing time of 2.65 months was similar in the CRCF groups (2.77 months; p = 0.440). Complication rates were 3/26 (11.5 %) in the CRCF group and 14/26 (53.4 %) in the ORTF group. Two patients in the CRCF group and eight patients in the ORTF group experienced skin irritation. In addition, two (7.7 %) patients in the CRCF group and 11 (42.3 %) patients in the ORTF group required implant removal because of symptoms due to the presence of the implants.

CONCLUSION

Surgical treatment of mild displaced (less than 8 mm) transverse patellar fractures by the CRCF technique provides satisfactory clinical results and excellent knee function, with little pain and a low incidence of complications at early follow-up (up to 6 months). These results suggest that the CRCF technique may be a superior alternative to conventional ORTF. Registration Trial (Chinese Clinical Trial Register): Current Controlled Trials ChiCTR-PRCH-14005017, registration dates 2014-06-14.

Current Treatment Strategies for Patella Fractures

Patella fractures can be caused by excessive tension through the extensor mechanism or a direct impact. Non-displaced fractures with an intact extensor mechanism can be treated nonoperatively. Surgical treatment is recommended for fractures that either disrupt the extensor mechanism or have greater than 2 to 3 mm of step-off and greater than 1 to 4 mm of displacement. Tension band fixation is the most commonly employed surgical technique; however, this can be technically demanding, especially in multifragmentary fractures. Symptomatic hardware is the most common complication following operative treatment. Functional impairment remains common after treatment of patella fractures. The purpose of this article is to review current treatment strategies to help optimize the management of patients with such patella fractures.

Interventions for treating fractures of the patella in adults

BACKGROUND

Fractures of the patella (kneecap) account for around 1% of all human fractures. The treatment of these fractures can be surgical or conservative (such as immobilisation with a cast or brace). There are many different surgical and conservative interventions for treating fractures of the patella in adults.

OBJECTIVES

To assess the effects (benefits and harms) of interventions (surgical and conservative) for treating fractures of the patella in adults.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register (2 May 2014), the Cochrane Central Register of Controlled Trials (The Cochrane Library, 2014, Issue 4), MEDLINE (1946 to April Week 4 2014), Ovid MEDLINE In-Process & Other Non-Indexed Citations (2 May 2014), Embase (1980 to 2014 Week 17), LILACS (1982 to 2 May 2014), trial registers and references lists of articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or quasi-RCTs that evaluated any surgical or conservative intervention for treating adults with fractures of the patella were eligible for inclusion. The primary outcomes were patient-rated knee function and knee pain, and major adverse outcomes.

DATA COLLECTION AND ANALYSIS

At least two review authors independently selected eligible trials, assessed risk of bias and cross-checked data extraction. Where appropriate, results of comparable trials were pooled.

MAIN RESULTS

We included five small trials involving 169 participants with patella fractures. Participant age ranged from 16 to 76 years. There were 68 females and 100 males; the gender of one participant was not reported. Two trials were conducted in China and one each in Finland, Mexico and Turkey.All five trials compared different surgical interventions. Two trials compared biodegradable versus metallic implants for treating displaced patella fractures; one trial compared patellectomy with advancement of vastus medialis obliquus versus simple patellectomy for treating comminuted patella fractures; and two trials compared percutaneous osteosynthesis (both procedures were 'novel' and one used a new device) versus open surgery for treating displaced patella fractures. All the trials had design flaws, such as lack of assessor blinding, which put them at high risk of bias, potentially limiting the reliability of their findings. No trial reported on health-related quality of life, return to previous activity or cosmetic appearance.Very low quality evidence from two trials (48 participants) comparing biodegradable versus metallic implants indicated little difference between the two interventions at two-year follow-up in the numbers of participants with occasional knee pain (1/23 versus 2/24), incurring adverse events (3/24 versus 1/24) or with reduced knee motion (2/23 versus 2/24). Neither trial reported patient-rated knee function scores. In one trial, as per routine practice, metallic implants were removed one year after surgery (four participants). The other trial did not report on this aspect.Very low quality evidence from one trial (28 participants) indicated that compared with simple patellectomy, patellectomy with advancement of vastus medialis obliquus surgery for treating comminuted patella fractures resulted in more participants with a 'good' result based on a subjectively rated score (12/12 versus 11/16; risk ratio (RR) 1.42, 95% confidence interval (CI) 1.01 to 2.01), fewer participants experiencing knee pain (5/12 versus 13/16; RR 3.11, 95% CI 1.01 to 9.60) and more participants with unlimited activity and no loss in quadriceps strength at four-year follow-up. The only adverse event reported was a patellar tendon subluxation in the simple patellectomy group.Neither trial comparing percutaneous osteosynthesis (using novel devices or methods) versus open surgery reported on patient-rated knee function scores. Very low quality evidence from two trials (93 participants) showed that percutaneous osteosynthesis improved knee pain measured using visual analogue scale (0 to 10 where 10 is worst pain) at one month (mean difference (MD) -2.24, 95% CI -2.80 to -1.68) and at up to three months (MD -1.87, 95% CI -2.45 to -1.29). This effect did not persist at six months (very low quality evidence from one trial). Very low quality evidence from the two trials showed significantly fewer participants with adverse events (loss of reduction, infection, hardware complications, delayed wound healing) after percutaneous surgery (8/47 versus 28/46; RR 0.28, 95% CI 0.14 to 0.55). Very low quality evidence from the two trials indicated better clinician-rated knee function scores after percutaneous fixation at two to three months and 12 months follow-up; however, the between-group difference was not clinically important at 24 months. Very low quality evidence showed a lower incidence of hardware removal in the percutaneous group at two years; however, the results in the two trials were heterogeneous and the reasons for removal were not given in detail.

AUTHORS' CONCLUSIONS

There is very limited evidence from RCTs about the relative effects of different surgical interventions for treating fractures of the patella in adults. There is no evidence from RCTs evaluating the relative effects of surgical versus conservative treatment or different types of conservative interventions.Based on very low quality evidence, biodegradable implants seem to be no better than metallic implants for displaced patellar fractures; patellectomy with vastus medialis obliquus advancement may give better results than simple patellectomy for comminuted patellar fractures; and two novel methods of percutaneous osteosynthesis may give better results than conventional open surgery. However, until conclusive evidence becomes available, treatment options must be chosen on an individual patient basis, carefully considering the relative benefits and harms of each intervention and patient preferences. Further randomised trials are needed, but in order to optimise research effort, these should be preceded by research that aims to identify priority questions.

Titanium mesh as a low-profile alternative for tension-band augmentation in patella fracture fixation: A biomechanical study

OBJECTIVES

We performed a simple biomechanical study to compare the fixation strength of titanium mesh with traditional tension-band augmentation, which is a standard treatment for transverse patella fractures. We hypothesised that titanium mesh augmentation is not inferior in fixation strength to the standard treatment.

METHODS

Twenty-four synthetic patellae were tested. Twelve were fixed with stainless steel wire and parallel cannulated screws. Twelve were fixed with parallel cannulated screws, augmented with anterior titanium mesh and four screws. A custom test fixture was developed to simulate a knee flexed to 90°. A uniaxial force was applied to the simulated extensor mechanism at this angle. A non-inferiority study design was used to evaluate ultimate force required for failure of each construct as a measure of fixation strength. Stiffness of the bone/implant construct, fracture gap immediately prior to failure, and modes of failure are also reported.

RESULTS

The mean difference in force at failure was -23.0 N (95% CI: -123.6 to 77.6N) between mesh and wire constructs, well within the pre-defined non-inferiority margin of -260 N. Mean stiffness of the mesh and wire constructs were 19.42 N/mm (95% CI: 18.57-20.27 N/mm) and 19.49 N/mm (95% CI: 18.64-20.35 N/mm), respectively. Mean gap distance for the mesh constructs immediately prior to failure was 2.11 mm (95% CI: 1.35-2.88 mm) and 3.87 mm (95% CI: 2.60-5.13 mm) for wire constructs.

CONCLUSIONS

Titanium mesh augmentation is not inferior to tension-band wire augmentation when comparing ultimate force required for failure in this simplified biomechanical model. Results also indicate that stiffness of the two constructs is similar but that the mesh maintains a smaller fracture gap prior to failure. The results of this study indicate that the use of titanium mesh plating augmentation as a low-profile alternative to tension-band wiring for fixation of transverse patella fractures warrants further investigation.

Percutaneous cannulated screws with tension band wiring technique in patella fractures

Introduction

Most patellar fractures are transverse involving the central third. Open reduction and stabilization of transverse patellar fractures is indicated if there is more than 2-3 mm of fragment separation and/or articular incongruity.

Surgical Technique

This study describes a percutaneous 2 cannulated screws and modified tension band wiring technique to treat transverse patellar fractures.

Materials and Methods

We performed 30 cases of displaced transverse patellar fractures with this technique. The clinical outcomes of these patients were evaluated with simple radiographs, range of motion and Lyshom score.

Results

This technique has shown to provide satisfactory clinical results and excellent knee functions.

Conclusions

This technique provide stable fixation, allows early motion exercise by minimizing injury to extensor mechanism and reduce cosmetic problem in scar.

Comparison of the cable pin system with conventional open surgery for transverse patella fractures

BACKGROUND

The cable pin system is an effective device for fixation of transverse patella fractures. However, whether this device provides superior results using a minimally invasive technique instead of conventional open surgery using the K wire tension band method is unclear.

QUESTIONS/PURPOSES

We asked whether a minimally invasive technique would be associated with (1) increased operative time; (2) reduced postoperative pain; (3) faster recovery of ROM; (4) higher knee scores; and (5) reduced complications.

METHODS

Forty patients with displaced transverse fractures of the patella participated in this prospective, randomized, controlled trial. Twenty of these patients underwent a minimally invasive technique and the others had conventional open surgery using K wires. Some data for six of the 20 patients who underwent the minimally invasive technique were published in an earlier prospective, observational trial. At postoperative intervals of 1, 3, 6, 12, and 24 months, pain was measured by VAS scores, active flexion and extension of the knee were measured in degrees by goniometry, and knee function was evaluated using the Böstman clinical grading scale.

RESULTS

Operative time was longer in the minimally invasive surgery group (54.3 ± 9.8 minutes versus 48.5 ± 6.1 minutes). Pain scores were better (lower) in the minimally invasive surgery group at 1 and 3 months but not at 6 months. Early flexion, ultimate flexion, and knee scores from 3 to 24 months, likewise, were better in the minimally invasive surgery group. Complications mostly related to symptomatic hardware were less common in the minimally invasive surgery group.

CONCLUSIONS

The minimally invasive technique is superior to conventional open surgery using K wires in terms of less early postoperative pain, better mobility angles of the injured knee, higher functional score of the injured knee, and decreased incidence of complications.

LEVEL OF EVIDENCE

Level I, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

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

BACKGROUND

Displaced patellar fractures are commonly stabilized with a modified anterior tension-band construct. The goal of the current study was to compare the incidence of complications after tension-band fixation of the patella with Kirschner wires as compared with cannulated screws.

METHODS

We performed a retrospective cohort study of consecutive, surgically treated patellar fractures. Patients were divided into two cohorts: fractures fixed with use of Kirschner wires and fractures fixed with use of cannulated screws. The primary outcome measure was early loss of fixation that necessitated revision surgery. Secondary outcomes included early postoperative infection and the need for implant removal.

RESULTS

Four hundred and forty-eight patellar fractures were studied. Kirschner wires were used for fixation in 315 (70%), and cannulated screws were used for fixation in 133 (30%). The incidence of fixation failure was 3.5% in the Kirschner-wire group and 7.5% in the screw group (p = 0.065). A postoperative infection occurred in 4.4% of patients in the Kirschner-wire group and 1.5% of patients in the screw group (p = 0.17). One hundred sixteen (37%) patients in the Kirschner-wire group and 30 (23%) in the screw group underwent elective implant removal (p = 0.003). After adjusting for confounding variables, a trend toward increased incidence of fixation failure with screws as compared with Kirschner wires was present (p = 0.083). Patients treated with Kirschner wires were twice as likely to undergo implant removal compared with those treated with screws (p = 0.002).

CONCLUSIONS

Serious complications are uncommon following treatment of patellar fractures with a modified tension-band technique, with use of either Kirschner wires or cannulated screws. In both groups the rate of fixation failure was low, as was the rate of postoperative infection. Symptomatic implants, the most common complication observed, were twice as frequent in patients treated with Kirschner wires.

Acute and old ruptures of the extensor apparatus of the knee in adults (excluding knee replacement)

Rupture of the extensor apparatus of the knee in adults is infrequent and dominated by patellar fracture, which in our experience is six times as frequent as quadriceps or patellar tendon tear. Patellar fracture poses few diagnostic problems and treatment is now well codified. Tension-band osteosynthesis is generally used, involving two longitudinal K-wires and wire in a figure-of-eight pattern looped over the anterior patella; sometimes, for more complex fractures, cerclage wiring is added to the tension band. Non-union is rare and generally well tolerated. Quadriceps tendon tear mainly affects patients over 40 years of age, in a context of systemic disease. Diagnosis is easily suggested by inability to actively extend the knee, but is unfortunately still often overlooked in emergency. In most cases, early surgical management is needed to reinsert the tendon at the proximal pole of the patella by bone suture. For chronic lesions, it is often necessary to lengthen the quadriceps tendon by V-Y plasty or the Codivilla technique. Patellar tendon tear, on the other hand, typically occurs in patients under 40 years of age, often involved in sports. Diagnosis is again clinically straightforward, but again may be missed in emergency, especially in case of incomplete tear. Surgery is mandatory in all cases. The procedure depends on the type of lesion: either end-to-end suture or transosseous reinsertion. In most cases repair is protected by tendon augmentation. Old lesions often require tendon graft or a tendon-bone-tendon-bone graft taken from the opposite side.

Treatment of transverse patellar fractures: a comparison between metallic and non-metallic implants

INTRODUCTION

Several methods of transverse patellar fixation have been described. This study compares the clinical outcome and the occurrence of complications of various fixation methods.

SOURCES OF DATA

The databases PubMed, Web of Science, Science Direct, Google Scholar and Google were searched.

AREAS OF AGREEMENT

A direct comparison between fixation techniques using mixed or non-metallic implants and metallic K-wire and tension band fixation shows no significant difference in clinical outcome between both groups. Additionally, studies reporting novel operation techniques show good clinical results.

AREAS OF CONTROVERSY

Studies describing the treatment of patients using non-metallic or mixed implants are fewer compared with those using metallic fixation.

GROWING POINTS

A large variety of clinical scoring systems were used for assessing the results of treatment, which makes direct comparison difficult.

AREAS TIMELY FOR DEVELOPING RESEARCH

More data of fracture treatment using non-metallic or mixed implants is needed to achieve a more balanced comparison.

Percutaneous tension band wiring for patellar fractures

PURPOSE

To evaluate outcome of percutaneous tension band wiring for transverse fractures of the patella.

METHODS

16 men and 7 women aged 27 to 65 (mean, 40) years underwent percutaneous tension band wiring for transverse fractures of the patella with a displacement of >3 mm. Pain, operating time, mobility, functional score, and complications were evaluated.

RESULTS

20 patients underwent successful percutaneous tension band wiring. The remaining 3 patients in whom closed reduction failed underwent open reduction and tension band wiring. The mean operating time was 46 (range, 28-62) minutes. The mean follow-up period was 20 (range, 15-30) months. At the latest follow-up, all patients had regained full extension. The objective score was excellent in 20 patients and good in 3, whereas the subjective score was excellent in 17, good in 5, and fair in one. All patients had radiological union at week 8. One patient had patellofemoral arthritis (secondary to a postoperative articular step). Two patients developed superficial infections, which resolved after antibiotic therapy. Mean thigh muscle wasting was 0.7 (range, 0.4-1) cm. Three patients encountered hardware problems (impingement/irritation of the skin over the knee) necessitating implant removal.

CONCLUSION

Percutaneous tension band wiring is a viable option for transverse fractures of the patella.

Distal femoral dome varus osteotomy: surgical technique with minimal dissection and external fixation

The results obtained when employing distal femoral varus osteotomy are variable. Our objective was to describe a surgical technique involving minimal dissection, semicircular osteotomy with external fixation for valgus angular deformities, and early weight bearing.

DESIGN

Series of cases.

SETTING

Orthopedic Referral Trauma Center.

PATIENTS

Sixteen patients with valgus angular deformities of >12°.

INTERVENTION

Wedge varus osteotomy, minimal dissection with external fixation using a standard system, multidirectional Newfix. Main outcome measurements included pain, surgical time, knee flexion and extension angles, and assessment of knee function based on the Hospital Special Surgery knee rating scale (HSSkrs).

RESULTS

Of 16 patients, 14 were evaluated to the end of the study. When we compared preoperative values with those obtained postoperatively at a mean of 24±2.1months, pain measurement was reduced from 7 to 2.1 (p=0.002), angle of flexion was reduced from 105.4±14.6° to 105.3±11.1° (p=0.06), and angle of extension, from -1.67 to -1.25° (p=0.6), while HSSkrs assessment increased from 67.5±2.7 to 79.4±5 (p=0.003). Two patients were excluded from the study, one due to infection that developed along the trajectory of a screw, and the other patient underwent complete arthroplasty of the knee, which was performed to combat the pain that was not being alleviated.

CONCLUSIONS

The technique improves function and reduces pain while facilitating early rehabilitation in 83% of cases.

Cannulated screw and cable are superior to modified tension band in the treatment of transverse patella fractures

BACKGROUND

Although the modified tension band technique (eg, tension band supplemented by longitudinal Kirschner wires) has long been the mainstay for fixation of transverse fractures of the patella, it has shortcomings, such as bad reduction, loosening of implants, and skin irritation.

QUESTIONS/PURPOSES

We conducted a retrospective comparison of the modified tension band technique and the titanium cable-cannulated screw tension band technique.

PATIENTS AND METHODS

We retrospectively reviewed 101 patients aged 22 to 85 years (mean, 56.6 years) with AO/OTA 34-C1 fractures (n = 68) and 34-C2 fractures (n = 33). Fifty-two patients were in the modified tension band group and 49 were in the titanium cable-cannulated screw tension band group. Followup was at least 1 year (range, 1-3 years). Comparison criteria were fracture reduction, fracture healing time, and the Iowa score for knee function.

RESULTS

The titanium cable-cannulated screw tension band group showed improved fracture reduction, reduced healing time, and better Iowa score, compared with the modified tension band group. In the modified tension band group, eight patients experienced wire migration, three of these requiring a second operation. There were no complications in the titanium cable-cannulated screw tension band group.

CONCLUSIONS

The titanium cable-cannulated screw tension band technique showed superior results and should be considered as an alternative method for treatment of transverse patellar fractures.

LEVEL OF EVIDENCE

Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.

Arthroscopically assisted percutaneous osteosynthesis of displaced transverse patellar fractures with figure-eight wiring through paired cannulated screws

INTRODUCTION

For treatment of displaced transverse patellar fractures, open reduction and internal fixation is the standard reconstructive method. The role of percutaneous osteosynthesis is still unclear and worth of further investigation. Our hypothesis is that satisfactory reduction and rigid fixation is possible for the treatment of displaced transverse patellar fractures with some percutaneous techniques. Here, we present and evaluate a minimally invasive technique for these patellar fractures.

PATIENTS AND METHODS

This is a retrospective study. Twenty-one patients with 21 transverse patellar fractures were treated with our percutaneous technique in acute phase. The minimally invasive surgery was achieved by closed reduction and fixation with modified Carpenter's technique, using figure-eight wiring through two parallel cannulated screws under the assistance of arthroscopy and fluoroscopy. The patients were followed up to an average of 38.8 months (range 26-48). Main outcome measurements included radiographic assessment, range of motion, Lysholm scores, complications, and reoperations.

RESULTS

Radiographically, all fractures healed at a mean of 11.0 weeks (range 9-13). Mean total range of motion of knee joint was 140.1° (range 127-152). Functional assessment of Lysholm scores was 93.9 points (range 86-100). Malreduction, loss of reduction, and infection were not observed in 21 patients. Complications were three cases (14%) of hardware irritation, and needed a second operation for removal.

CONCLUSIONS

Under the control of arthroscopy and fluoroscopy, we successfully treated 21 displaced transverse patellar fractures by percutaneously osteosynthesis. This is a safe and reproducible method for transverse patellar fractures. However, it is not indicated for severely comminuted fractures.

Patellar fractures in adults

Patellar fracture is a common injury caused by excessive tension through the extensor mechanism or a direct blow. The intact patella increases the leverage and efficiency of the extensor mechanism and articulates with the femoral trochlea. Patellar fractures can lead to stiffness, extension weakness, and patellofemoral arthritis. Nonsurgical management is indicated for nondisplaced fractures with an intact extensor mechanism. Surgical fixation is recommended for fractures that either disrupt the extensor mechanism or demonstrate >2 to 3 mm step-off and >1 to 4 mm of displacement. Anatomic reduction and fixation with a tension-band technique is associated with the best outcomes; however, symptomatic hardware is a frequent complication. Open fractures are associated with more complications than closed fractures. These complications can be mitigated with timely débridement, irrigation, and internal fixation.

Implant removal following surgical stabilization of patella fracture

Patella fractures are relatively common injuries. Tension band wiring is commonly used to treat displaced patella fractures. The goal of this study was to assess the outcome and implant removal rate following surgical stabilization of patella fracture. A consecutive series of 67 patients over a 6-year period was reviewed. Minimum follow-up to fracture healing (3 months) was available in 63 patients. Forty-three men and 24 women with a mean age of 49 years (range, 14-90 years) underwent surgical stabilization of patella fracture. Three open fractures and associated injuries were noted in 22 patients. Surgical treatment methods used were: tension band wiring in 44, tension band wiring with cerclage wire in 13, tension band wiring with screws in 4, and screw fixation in 6. All fractures united. Two superficial infections responded to oral antibiotics. One patient had revision surgery at 6 weeks. Twenty-two patients required implant removal for implant-related symptoms. Mean follow-up in asymptomatic patients was 8 months (range, 3-18 months) and in patients with implant-related problems was 17 months (range, 10-36 months). Four patients were lost to follow-up. Surgical stabilization of patella fractures by current techniques demonstrated satisfactory fracture union. However, 1 in 3 required surgery for implant-related symptoms. In the younger than 60 years group, the implant removal rate was 40%. This high rate of implant removal must be discussed with the patient prior to surgery. Newer techniques to avoid skin irritation should be considered.

Biomechanical comparison of a new staple technique with tension band wiring for transverse patella fractures

BACKGROUND

The tension band wiring technique is the most common method of transverse patella fracture fixation. Since post-operative instabilities have been reported for this technique, alternative osteosynthesis solutions are of interest. We investigated the biomechanical behaviour of a new staple technique for treatment of transverse patella fractures in a cadaveric model.

METHODS

Eight human cadaveric knees with femur and tibia including soft tissue were used. A transverse osteotomy of the patella was created. Each specimen was fixed consecutively with tension band wiring and two Nitinol compression staples. Testing was performed by pull on the quadriceps tendon between a 90 degrees flexed position and full knee extension for up to 5,000 cycles.

FINDINGS

At 1,000 cycles, fracture site displacements in flexion and extension were significantly smaller for the staple group at the ventral aspect of the patella as compared to the tension band wiring group. With a failure criterion of 2mm fracture site displacement, cycles until failure were significantly smaller for the staple group.

INTERPRETATION

This study provides evidence based on a cadaveric model that compression staples have a promising potential to treat transverse patella fractures.

Arthroscopic-assisted reduction and stabilization of transverse fractures of the patella

Most patellar fractures are transverse involving the central third. Open reduction and stabilization of transverse patellar fractures is indicated if there is more than 2-3 mm of fragment separation and/or articular incongruity. Arthroscopic-assisted reduction and stabilization of displaced fractures of the patella had been reported as an alternative to open technique. The aim of this study was to report the results of arthroscopic-assisted reduction and fixation of displaced transverse fractures of the patella. Fourteen patients with 14 displaced transverse fractures of the patella were included in this prospective study. Patients were treated by arthroscopic-assisted closed reduction of the fracture with percutaneous screw fixation. Patients were followed up for a mean period of 26 months. All patients were males with an average age of 34 years. All fractures united in a mean period of 7 weeks. Twelve patients regained full knee range of motion and two patients had 10 degrees loss of full flexion. All patients regained full knee extension. Thigh muscle wasting was observed in nine patients with a mean value of 0.8 cm. The mean final Lysholm score was 93. Arthroscopic-assisted reduction and percutaneous screw fixation is an appropriate technique for displaced transverse patellar fractures without major separation or comminution. It offers good functional outcome with minimal complications.