Distinct risk profiles for short-term surgical complications and venous thromboembolism exist among extensor mechanism repair procedures

PURPOSE

Extensor mechanism injuries, which comprise patella fractures, patella tendon tears and quadriceps tendon tears, are severely debilitating injuries and a common cause of traumatic knee pathology that requires surgical intervention. Risk factors for short-term surgical complications and venous thromboembolism (VTE) in this population have not been well characterised. The aim of this study was to identify perioperative risk factors associated with these short-term complications.

METHODS

The National Surgical Quality Improvement Program database was used to identify patients who underwent an isolated, primary extensor mechanism repair from 2015 to 2020. Patients were stratified by injury type. Demographic data were collected and compared. A multivariate logistic regression was used to control for demographic and comorbid factors while assessing risk factors for developing short-term complications.

RESULTS

A total of 8355 patients were identified for inclusion in this study. Overall, 3% of patients sustained short-term surgical complications and 1% were diagnosed with VTE within 30 days of surgery. Patella fracture fixation had a nearly twofold higher risk for surgical complications compared to quadriceps tendon repair (p = 0.004). Patella tendon repair had a twofold higher risk for VTE (p = 0.045), specifically deep vein thrombosis (p = 0.020), compared to patella fracture fixation. Increasing age, smoking and American Society of Anesthesiologists Classifications 3 and 4 were also found to be risk factors for surgical complications (p = 0.012, p = 0.004, p = 0.011 and p = 0.032, respectively).

CONCLUSION

This study used a nationally representative, widely validated, peer-reviewed database to provide valuable insights into risk factors for short-term postoperative complications associated with extensor mechanism repair procedures, revealing notable differences in risk profiles among distinct surgical procedures. The results of this study will inform surgeons and patients in enhancing risk assessment, guiding procedure-specific decision-making, optimising preoperative care, improving postoperative monitoring and contributing to future research of extensor mechanism injuries.

LEVEL OF EVIDENCE

Level III.

Patella Fracture After Total Knee Arthroplasty: A Review

The management and underlying causes of patellar periprosthetic fractures (PPF) after total knee arthroplasty (TKA) constitute an issue of growing importance given the rising frequency of these procedures. Patella periprosthetic fractures, though relatively rare, pose significant challenges and are a frequent indication for revision surgeries. Despite a decrease in overall incidence, PPFs remain the second most common type of periprosthetic fractures after TKA. Several factors have been identified and associated with patient-specific factors, surgical technique errors, and implant-related causes. Currently extensor apparatus integrity, bone stock, and component loosening are the major concerns and indications for the selective treatment approach. In this study, a thorough review of the existing literature was performed summarizing the epidemiology, clinical manifestation, treatment approach, and functional outcome of PPF. This review aims to underline the significance of such predisposing factors, point out the severity of PPF, and offer insights into the optimal intra- and post-operative management of the patella.

Impetigo Surgical Site Infection Following Open Reduction and Internal Fixation of a Patella Fracture

Impetigo is a pediatric skin infection characterized by the presence of pathognomonic "honey-crusted" lesions caused by either Staphylococcus aureus or Streptococcus pyogenes. The diagnosis of impetigo is largely based on clinical judgment, confirmatory skin cultures, and Gram staining. Surgical site infections following patellar surgery are a relatively uncommon occurrence, with the most common causative organisms being Staphylococcus aureus, Streptococcus pyogenes, Pseudomonas aeruginosa, and other gram-negative bacilli. Surgical site infections have a range of risk factors that largely depend on patient characteristics and surgical logistics. We report the first documented case in the literature of a surgical impetigo infection with diagnostic skin lesions following open reduction and internal fixation of a patellar fracture in a 24-year-old female.

Surgical debridement and continuous irrigation for early surgical site infection caused by Staphylococcus aureus with a closed patella fracture surgery: A case report

INTRODUCTION

Management of postoperative surgical site infection (SSI) is a huge challenge to orthopedic surgeons, and significantly impacts patients and their families due to long treatment cycles and associated discomfort experiences.

PRESENTATION OF CASE

A 68-year-old woman without a medical history of any comorbidities, diabetes, hypertension, allergies, or tuberculosis, was admitted to our hospital complaining of right knee pain following a fall. X-ray and CT scans revealed a closed right patella fracture. The patient underwent open reduction and internal fixation with tension band wiring and circle wire. Preoperative assessment showed normal nutritional status. Prophylactic cefazolin sodium pentahydrate was administered 30 min preoperatively and maintained for 24 h post-operation to prevent infection. The patient was discharged 3 days after the operation. However, the wound exhibited signs of infection: redness, swelling, and the presence of secretions. Outpatient dressings and oral antibiotics were prescribed but failed to control the infection, leading to rehospitalization. Surgical debridement and continuous articular irrigation were implemented to address the infection. Secretion cultures were taken to identify the causative bacteria. Levofloxacin and Rifampicin were used according to drug sensitivity tests. However, the patient experienced severe knee swelling and an iodine irritative reaction subsequently. Anti-allergic treatment and normal saline dressings were applied to alleviate swelling, pain, and skin irritation. MRI results indicated arthroedema and possible infection necessitating further surgical debridement, the patient rejected additional surgery and requested discharge. Levofloxacin and Rifampicin were used for a month to control the infection after discharge, accompanied by regular rehabilitation exercises. Fortunately, the infection was successfully managed, and knee function was satisfactorily restored.

DISCUSSION

SSI after patella fracture surgery can lead to a worse quality of life, serious economic burden, and psychological distress. Therefore, effective treatment methods for managing postoperative SSIs are very important.

CONCLUSION

Sufficient surgical debridement is vital to remove infection tissue of early SSI caused by Staphylococcus aureus with a closed patella fracture surgery. Continuous articular irrigation and sensitive antibiotics help control infection, and active rehabilitation training improves knee function recovery.

A study of fracture lines distribution characteristics in complete articular fractures of the patella

Objective

The objective of this study was to unveil the characteristics of fracture lines distribution and explore its clinical significance of complete articular fractures of the patella.

Methods

A consecutive series of image data from 88 patients with complete articular patella fractures were retrospectively included. Three-dimensional reconstruction images of the patella fractures were created and collected. Subsequently, these reconstructed images were visually overlaid onto a standard anterior and posterior patella template. The fracture lines were then identified, traced onto the template, and utilized to generate patella fracture maps. Furthermore, the incidence rate of patella fracture lines involving the distal pole was analyzed.

Results

The maps depict the fracture lines of complete articular patella fractures. For simple and complex patella fractures, the primary fracture lines primarily converge within the Middle and Lower regions, exhibiting a transverse pattern. Conversely, the primary fracture lines in comminuted patella fractures are randomly dispersed across the patella. Examining the maps, approximately 63.6% (56/88) of complete articular patella fractures exhibited involvement of the distal pole in the anterior view, while 48.9% (43/88) displayed distal pole fractures in the posterior view. The incidence of distal pole injury increased progressively with the severity of patella fractures.

Conclusion

The patterns and distribution of fracture lines in cases of complete articular patella fractures are prominently illustrated on the constructed fracture maps. Familiarity with these common characteristics of complete articular patella fracture, especially with the distal pole injury, can aid surgeons in developing preoperative planning, executing surgical strategies effectively, and reducing inappropriate treatment.

Patellar Avulsion Fracture

We report on the case of a 52-year-old male who sustained a transverse patellar fracture after tripping on uneven pavement. These fractures can be easy to miss on anteroposterior views, highlighting the importance of multiple radiographic views of the knee. Examination of the knee is also important, as initial clinical appearance can be benign. These fractures are most often seen in adolescents, which makes the current case somewhat unusual.

Patellar Fracture Repair Using FiberWire

Patellar fractures are injuries caused by the direct impact on the bone or excessive stress on the extensor mechanism. The extensor mechanism is a structure formed by the quadriceps, the patella, and the patellar tendon, as well as ligaments. We present the case of a 53-year-old male who suffered a fall from a ladder after attempting to fix a ceiling light in his home. He went to the emergency department a few times before he was admitted due to his inability to walk secondary to a fracture located at the inferior pole of the left patella. This fracture was fixed with open reduction and internal fixation using drill holes and FiberWire®.

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

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

Biomechanical evaluation of three fixation methods in a feline transverse patella fracture model

OBJECTIVES

This study aimed to compare the biomechanical properties of three stabilisation techniques in feline patella transverse fractures and select the strongest method with potentially minimal complications.

METHODS

Patella fracture was simulated in 27 feline cadaveric pelvic limbs (mean weight of the cadavers 3.78 kg), and the limbs were randomly grouped to be stabilised with one of the three stabilisation methods. The modified tension band wiring technique with a single Kirschner wire (0.9 mm) and figure-of-eight wiring (20 G) was applied to group 1 (n = 9). Group 2 (n = 9) was stabilised with a combination of circumferential and figure-of-eight wiring techniques with orthopaedic wire (20 G). Group 3 (n = 9) was stabilised with the same technique as group 2, but with #2 FiberWire. The knee joints were positioned and fixed in the neutral standing angle (135°) and tested by applying tensile force. The loads at gap formations of 1, 2 and 3 mm were recorded, and the maximum failure load was measured in each group.

RESULTS

In all the loads at displacement (1, 2 and 3 mm), group 3 was significantly stronger than groups 1 and 2, respectively (P <0.017). Group 3 (261.0 ± 52.8 N) showed significantly stronger fixation in the maximum load compared with group 1 (172.9 ± 45.6 N) (P <0.017). No significant difference was observed between groups 1 and 2 (204.9 ± 68.4 N) or between groups 2 and 3.

CONCLUSIONS AND RELEVANCE

This study shows that the combination of circumferential and figure-of-eight techniques with FiberWire is more resistant to displacement than metal wire in this ex vivo feline patella fracture model.

Trends and epidemiology of knee extensor mechanism injuries presenting to United States emergency departments from 2001 to 2020

OBJECTIVES

Injuries to the native extensor mechanism (EM) of the knee are potentially disabling and often require surgical treatment. Large-scale, updated epidemiological data on these injuries is lacking. The objective of the current study was to examine recent trends in EM injuries presenting to United States (US) Emergency Departments (EDs) over the last 20 years using a nationally representative sample.

METHODS

This study retrospectively analyzed the National Electronic Injury Surveillance System (NEISS) database to identify cases of EM injuries (defined as either a quadriceps tendon rupture, a patella fracture, or a patellar tendon rupture) presenting to EDs in the US from 2001 to 2020.

RESULTS

During the study period, an estimated 214,817 EM injuries occurred in an at-risk population of 6,183,899,410 person-years for an overall incidence rate of 3.47 per 100,000 person-years. Patella fractures (PFs) were the most common injury type, representing 77.5% of all EM injuries (overall incidence rate: 2.69), followed by patellar tendon ruptures (PTRs; 13.5%; incidence: 0.48) and quadriceps tendon ruptures (QTRs; 9%; incidence: 0.31). Demographic characteristics and mechanisms of injury differed between injury types. Annual incidence rates increased significantly during the study period for all EM injury types, with PTRs demonstrating the largest relative increase (average annual percent increase: PF, 2.8%; PTR, 7.2%; QTR, 5.3%). Accounting for population growth yielded an increasing incidence of all EM injuries combined from 3.65 in 2001 to 4.9 in 2020. The largest relative increases in incidence rates were observed in older age groups.

CONCLUSION

Extensor mechanism injuries of the knee are increasing in the US, which likely reflects an aging and more active population. These types of injuries are associated with substantial functional impairment and recent increases in incidence rates highlight the need for injury prevention and management strategies.

Clinical application of Kirschner wires combined with 5-Ethibond fixation for patella fractures

Background

Patella fractures that require surgery are conventionally treated using Kirschner wires (K-wires) and stainless steel wires. In recent years, the nonabsorbable polyester has been reported to have excellent outcomes clinically. Therefore, the goal of our study was to evaluate the effects of Kirschner wires combined with 5-Ethibond on treating patellar fractures.

Methods

From July 2018 to January 2022, 22 patella fracture patients were treated with Kirschner wires combined with 5-Ethibond. Radiographs of the knees were used to evaluate fracture healing and hardware complications. The clinical results were evaluated through the functional score, knee joint range of motion (ROM), and Bostman patella fracture functional score.

Results

The average age of patients was 57.4 ± 11.9 (range 33-74) years. The mean follow-up time was 15.2 ± 7.6 (range 4-36) months. The mean operation time was 56.8 ± 8.7 (range 45-80) min. The entire patients had bony union at an average of 10.5 ± 1.9 (range 8-14) weeks. At the final follow-up, the mean range of postoperative ROM was 123.4° ± 14.6° (range 95°-140°), and the functional score was 28.7 ± 1.2 (range 26-30) points. No patient exhibited internal fixation failure, and no symptomatic implants or skin complications were recorded.

Conclusions

The fixation approach using K-wires combined with 5-Ethibond has a lower complication rate and delivers superior clinical results. This research reveals that such technology is a safe and prospective substitute for conventional metal fixation approaches.

Inferior Pole Sleeve Fracture of the Patella in an Adolescent: A Case Report

An 11-year-old boy was admitted to our hospital due to severe pain in his right knee when he landed after jumping over a vaulting box. A plain X-ray image and computed tomography scan showed an avulsion fracture of the lower pole of the patella and patella alta. Furthermore, magnetic resonance imaging (MRI) revealed an articular cartilage lesion and rupture between the inferior pole of the patella and the patella tendon. We diagnosed a sleeve fracture of the patella and performed surgical treatment. Open reduction and internal fixation were performed by the pull-out technique using transosseous no. 2 MaxBraid™​​​​​​ ​(Zimmer Biomet, Tokyo, Japan) sutures. While postoperative weight-bearing was permitted, the knee joint was immobilized in a brace for four weeks. Three months of postoperative assessment revealed excellent functional outcomes.

Efficient Recognition and Closed Reduction of Locked Lateral Patella Dislocation

Patellar dislocation is not an uncommon injury in the general population that can often be managed in the emergency room with a closed reduction. However, rarely, the patella can become impacted on the lateral femoral condyle and become resistant to closed reduction techniques, which is known as a locked patellar dislocation. This injury is reported in the literature as requiring advanced imaging with a costly workup, operative intervention, or extensive manipulation under general anesthesia, and, to our knowledge, has never been documented to be closed reduced outside the operating room. In this report, we present a 17-year-old male with a locked lateral patella dislocation and describe a new approach to efficiently diagnose and close reduce this injury in the ER under conscious sedation without advanced pre-treatment studies or urgent treatment in the operating room (OR).

Adjunct neutralization plating in patella fracture fixation: a technical trick

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

Risk factors and new inflammatory indicators of deep vein thrombosis after adult patella fractures

OBJECTIVE

This study aimed to investigate the association between new inflammatory indicators at admission and the occurrence of preoperative deep vein thrombosis (DVT) in patients with patella fractures.

METHODS

A retrospective analysis of the medical records of patients aged 18 years or older who underwent surgical treatment for unilateral closed patella fractures at our hospital between August 2016 and August 2020. The incidence of preoperative DVT was detected by Duplex ultrasound (DUS). Partial blood routine and biochemical indexes were collected at admission, and the neutrophil-to-lymphocyte ratio (NLR), monocyte-to-lymphocyte ratio (MLR), and platelet-to-lymphocyte ratio (PLR) of inflammatory indexes were also calculated. ROC was used to analyze the cut-off value NLR, MLR, and PLR for predicting preoperative DVT, and univariate and multivariate analyses of the risk factors for preoperative DVT of patella fractures, and to verify whether other risk factors affecting the relationship between validation indexes and preoperative DVT.

RESULTS

A total of 500 patients were included, of which 39 patients (7.8%) developed preoperative DVT. After univariate and multivariate analysis, preoperative time (in each day delay), male (vs. female), D-dimer > 0.6 mg/L, total cholesterol (TC) > 5.6 mmol/L, and PLR > 189.8 were the risk factors for preoperative DVT in patients with patella fracture. Inflammation index PLR combined with the other four risk factors significantly improved the predictive efficacy of preoperative DVT compared with PLR (P = 0.009).

CONCLUSION

Inflammatory index PLR is a risk factor for preoperative DVT in patients with patella fracture, and the efficacy of PLR in predicting DVT can be significantly improved when other risk factors (male, D-dimer > 0.6 mg/L, TC > 5.6 mmol/L, and PLR > 189.8 of preoperative time in each day delay) are combined. These data are useful for the clinical identification of patients at high risk of preoperative DVT in patella fractures.

Patellar fracture among elite-level European soccer players: 4-year case-control cohort analysis of return to play, re-injury, and player performance

OBJECTIVES

There is a paucity of literature investigating the relationship between patellar fracture and player performance of professional soccer players following return to play (RTP). Our goal is to determine the rate of RTP, time to RTP, and effect on player performance following patellar fracture.

METHODS

Twenty-one elite-level European professional soccer players who sustained a patellar fracture between 1999 and 2018 were identified via a publicly accessible database. Athletes with patellar fracture were matched to controls by age, height, years played in the league, season of injury, and position. Change in performance metrics between one season prior to injury and the following four seasons after injury were compared.

RESULTS

Players with patellar fracture were absent for a mean 207.95 ± 135.55 days and 16.81 ± 31.79 games. Fifteen (71%) players returned to play after injury with 67% returning within 1 season after injury. Injured players did not demonstrate significant change in performance metrics at any of the follow-up timepoints compared to control. Subgroup analysis showed that attackers recorded approximately 1200 fewer minutes played per season than pre-injury levels 2 seasons following injury, significantly fewer (p < 0.05) than the control cohort recording similar minutes per season throughout the study period. Midfielders and defenders demonstrated similar fluctuations in performance to the control cohort for both field time and performance metrics (p > 0.05).

CONCLUSION

Seventy-one percent of players RTP after patellar fracture with an associated absence of 7 months and 17 missed games. Overall, injured players did not demonstrate a significant decline in performance as demonstrated by games played, total minutes played per season, minutes per game, assists, and goals 1 season after injury. Attackers played fewer minutes during the season of and 2 seasons after the initial injury.

The Effect of Exercise Intervention on Disability and Kinesiophobia in a Retired Athlete With Old Patella Fracture: A Case Report

Objectives: To evaluate the effect of exercise intervention on disability, pain, and kinesiophobia in a retired athlete with old patella fracture. Methods: A 34-year-old retired football player with old patella fracture conducted the exercise intervention for 12 weeks, 1 h each time, three times a week. the retired football player completed the Lysholm Knee Score (LKS), Visual Analog Scale (VAS), and the Tampa Scale for Kinesiophobia (TSK) were measured at pre-intervention, mid-intervention, and post-intervention. Results: Based on the functional training perspective, the retired athlete was subjected to two stages of exercise intervention for a total of 12 weeks. The patient's LKS score increased from 76 to 95, and the pain level of various physical states was relieved. When walking, the VAS score was reduced from 3 to 1, and when running, the VAS score was reduced from 5 to 2. Jumping VAS score for actions was reduced from 6 to 3, and the VAS score for of daily life activities was reduced from 3 points to 2. The patient's TSK score from 50 to 37. Conclusion: A 12-week exercise intervention could improve knee joint function, relieve pain and relieve kinesiophobia.

Combined internal fixation and transarticular external skeletal fixation to treat traumatic patellar fractures in five dogs

CASE HISTORY

Medical records of dogs (n = 5) that had been treated for patellar fracture with transarticular external skeletal fixation (TA-ESF) to augment internal fixation, at a single referral hospital in the United Kingdom between 2015 and 2017, were reviewed.

CLINICAL FINDINGS AND TREATMENT

At presentation, two dogs had polar patellar fractures, two had comminuted fractures and one dog had a transverse fracture. The median age at the time of the surgery was 21 (min 8, max 132) months and the median body weight was 19.0 (min 8.3, max 28.6) kg. In all cases, TA-ESF (Type IA lateral triangulated or modified Type II) was used in combination with internal fixation with pins and/or orthopaedic wire, supported by nylon leader line (patella-to-tibia mattress suture) and/or absorbable suture in a locking loop and/or circum-patellar pattern. All cases had short-term (6-12 weeks) post-operative radiographic follow-up, which showed evidence of fracture healing in 2/5 cases. All TA-ESF were removed 6 or 7 weeks post-operatively and four dogs had minor complications related to TA-ESF. More than 2 years post-operatively, the owners of all dogs were contacted and questioned using the Liverpool Osteoarthritis in Dogs questionnaire regarding the mobility of their pet. Four of the five cases were re-examined to evaluate their long-term outcomes. Based on the results of goniometric measurement of stifle range of motion, subjective gait assessment and objective gait analysis with a pressure-sensitive walkway, all dogs showed a satisfactory outcome at the final follow-up.

CLINICAL RELEVANCE

A combination of internal fixation and TA-ESF for stabilisation of traumatic patellar fractures is a valid treatment option. Further investigations with larger case numbers are necessary to evaluate success and complication rates.

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.

Surgical Management with Self-Locking Pins and Circumferential Wiring for Treating Comminuted Patella Fractures Achieved Seiza-Style Sitting

Surgical fixation of comminuted patella fractures is technically challenging. Despite the fact that tension band wiring or screw fixation are the most common surgical procedures, these surgical techniques have crucial limitations for laterally scattered fragments. We demonstrate two cases with comminuted patella fractures undergoing surgical fixation with self-locking pin and circumferential wiring, confirming the rigid fixation achieving deep knee flexion. After midline longitudinal skin incision, 2.0 mm stainless pins (AiMedic MMT, Tokyo, Japan) were inserted radially to penetrate each fragment and 1.2 mm stainless wire was circumferentially looped and self-locked in the holes on the pins, which satisfied rigid fixation. Any restrictions in range of motion and weight bearing were required postoperatively and 3- to 6-month postoperative cares achieved seiza-style sitting with deep knee flexion.

Epidemiology of Acute Extensor Mechanism Injuries in Collegiate-Level Athletes in the United States

BACKGROUND

Extensor mechanism injuries involving the quadriceps tendon, patella, or patellar tendon can be a devastating setback for athletes. Despite the potential severity and relative frequency with which these injuries occur, large-scale epidemiological data on collegiate-level athletes are lacking.

STUDY DESIGN

Descriptive epidemiology study.

LEVEL OF EVIDENCE

Level 4.

METHODS

Knee extensor mechanism injuries across 16 sports among National Collegiate Athletic Association (NCAA) men and women during the 2004-2005 to 2013-2014 academic years were analyzed using the NCAA Injury Surveillance Program (NCAA-ISP). Extensor mechanism injuries per 100,000 athlete-exposures (AEs), operative rate, annual injury and reinjury rates, in-season status (pre-/regular/postseason), and time lost were compiled and calculated.

RESULTS

A total of 11,778,265 AEs were identified and included in the study. Overall, 1,748 extensor mechanism injuries were identified, with an injury rate (IR) of 14.84 (per 100,000 AEs). N = 114 (6.5%) injuries were classified as severe injuries with a relatively higher median time loss (44 days) and operative risk (18.42%). Male athletes had higher risk of season-ending injuries in both all (3.20% vs 0.89%, P < 0.01) and severe (41.54% vs 16.33%, P < 0.01) extensor mechanism injuries. Similarly, contact injuries were more frequently season-ending injuries (4.44% vs 1.69%, P = 0.01). Women's soccer (IR = 2.59), women's field hockey (IR = 2.15), and women's cross country (IR = 2.14) were the sports with the highest rate of severe extensor mechanism injuries.

CONCLUSION

Extensor mechanism injuries in collegiate athletes represent a significant set of injuries both in terms of volume and potentially to their athletic careers. Male athletes and contact injuries appear to have a greater risk of severe injuries. Injuries defined as severe had a higher risk of operative intervention and greater amount of missed playing time.

CLINICAL RELEVANCE

Knowledge of the epidemiology of extensor mechanism injuries may help clinicians guide their athlete patients in sports-related injury prevention and management.

Simultaneous Bilateral Patella Fracture After Single Stage Bilateral Total Knee Arthroplasty: A Report of Two Cases and Literature Review

INTRODUCTION

Periprosthetic patellar fracture after total knee arthroplasty (TKA) is an uncommon yet devastating complication, and management of these fractures is challenging with unreliable results. An isolated bilateral patellar fracture is often associated with systemic diseases, steroid usage, and repeated microtrauma. Isolated simultaneous bilateral periprosthetic patellar fracture after TKA is seldom reported in the literature.

CASE REPORT

This report consists of two cases of simultaneous isolated closed bilateral eriprosthetic patellar fracture after TKA, treated with open reduction and internal fixation of patella using tension band wiring. Union was achieved in both cases with satisfactory knee range of motion without significant extension lag.

CONCLUSION

Regardless of the fact that surgical outcome of periprosthetic fracture of the patella has unpredictable and poor results in past, it can be considered for acute traumatic periprosthetic patella fractures with less comminution and good bone stock to avoid revision arthroplasty and poor outcome.

Hoffa's Fracture with Associated Injuries Around the Knee Joint: An Approach to a Rare Injury

Fractures of the distal femur typically occur in the axial and sagittal planes. A Hoffa fracture is a coronal plane fracture of the femoral condyle, which accounts for 8.7% to 13% of distal femoral fractures. It is usually associated with other injuries around the knee joint and hence is often missed. We conducted a comprehensive systematic review of papers published in the English language using PubMed, Web of Science, Scopus, and the Cochrane Database, which reported Hoffa's fracture associated with other injuries around the knee joint. We selected 11 eligible papers for final analysis and review. These papers had 12 patients with Hoffa’s fracture, with associated injuries around the knee joint. The associated injuries with Hoffa’s fracture were in the ipsilateral distal femur, proximal tibia fractures, patellar dislocation, patella fracture, and patellar tendon incarceration. The management principles for Hoffa's fracture with associated injuries around the knee joint are: having a high clinical index of suspicion for these injuries, obtaining all trauma series radiographs and computed tomography of the knee, achieving complete articular incongruity, and restoring the functions of the knee joint.

Comparing 3 Different Techniques of Patella Fracture Fixation and Their Complications

Introduction:

Patella fractures managed by fixation with metal implants often cause local soft tissue irritation and necessitate implant removal. An alternative is to utilize suture-based fixation methods. We have adopted suture and hybrid fixation in the routine management of patella fractures. Here, we compare the results of 3 fixation techniques.

Materials and Methods:

Eighty-seven eligible patients underwent patella fracture fixation over a 3-year period. As determined by fracture configuration, patients received (1) suture fixation (transosseous sutures and figure-of-eight tension banding with FiberWire), (2) hybrid fixation (transosseous FiberWire sutures and metal tension banding), or (3) metal fixation. Primary outcome measures included reoperation rate and soft tissue irritation. Secondary outcomes included surgical complications, radiological, and functional parameters.

Results:

Reoperation rate was highest for metal fixation (25/57, 43.9%) and lowest for suture fixation (2/13, 15.4%). Soft tissue irritation necessitating implant removal was the predominant reason for reoperation and was significantly less prevalent following suture fixation (1/13, 7.7%, P < .01). Hybrid fixation resulted in similar rates of soft tissue irritation (6/17, 35.3%) and implant removal (7/17, 41.2%) as compared to metal fixation. There was a significant increase in patella baja (13/17, 76.5%) and reduction in Insall-Salvati ratio (0.742; 95% confidence interval: 0.682-0.802) following hybrid fixation as compared to the other 2 fixation methods (P < .05).

Discussion:

Suture fixation results in the least amount of soft tissue irritation and lowest reoperation rate, but these advantages are negated with the addition of a metal tension band wire. Hybrid fixation also unbalances the extensor mechanism.

Conclusion:

Patients should be counseled as to the expected sequelae of their fixation method. Suture fixation is the favored means to fix distal pole fractures of the patella. An additional metal tension band loop may confer additional stability but should be applied with caution.

Is There Any Role for Direct Repair of Extensor Mechanism Disruption Following Total Knee Arthroplasty?

BACKGROUND

Extensor mechanism disruption remains a challenging problem in total knee arthroplasty (TKA) with historically poor outcomes. The purpose of our study is to determine if patients undergoing acute extensor mechanism repair had different outcomes than patients undergoing allograft reconstruction.

METHODS

We reviewed a series of 126 total knee arthroplasty patients requiring surgical repair or reconstruction of an extensor mechanism injury from 2005 to 2014 with a minimum of 24 months of follow-up. Demographics, comorbidities, Knee Society Scores, time from injury, and reoperations were all recorded from the medical record. A poor outcome was defined as an extensor lag >30°, postoperative Knee Society Scores <60, or a reoperation. A multivariate analysis was then performed to identify independent risk factors for a poor outcome.

RESULTS

Of the 126 patients, there were 58 patients who underwent direct extensor repair (46%) and 68 patients who underwent allograft reconstruction (54%) at a mean postsurgical follow-up of 81.2 months. Rates of poor outcomes were comparably high in both groups (33% vs 44%, P = .192). Patella tendon repair had the highest rate of poor outcomes compared to quadriceps repair and patella fixation (63% vs 22% vs 8%, P = .002). Independent risk factors for poor outcomes included patients with a history of infection (odds ratio 4.559, P = .002) and injury greater than 2 weeks duration (odds ratio 4.237, P = .031).

CONCLUSION

Outcomes following direct extensor mechanism are comparable to extensor mechanism allograft reconstruction; however, patients should be counseled regarding poor outcomes. Direct repair of patellar tendon injuries should likely be avoided due to prohibitively high complication rate.

A novel technique of using a miniature plate in combination with tension band wiring to treat comminuted patellar fractures

Traditionally, tension band fixation has been used for treating simple fracture patterns; however, fixation remains a challenge, especially for comminuted fractures. We describe a new method of operation using a combination of a miniature plate with tension band wiring to treat comminuted patellar fractures. The aim of this technique is to transform complicate fractures into simple transverse fractures. As far as we know, no studies using a similar method have been found.The purpose of this study was to assess the effectiveness of a novel technique in which a miniature plate is used in combination with tension band wiring to treat comminuted patellar fractures.Between March 2013 and May 2015, 16 patients with closed, displaced, comminuted fractures of the patella were included in the present study. All subjects underwent fixation using a combination of a miniature plate with a tension band wire. Knee function and patient status were evaluated at 12 months using the Böstman knee score and Lysholm knee scale.The average follow-up period was 15.6 months (range, 12-20 months). At the 12-month follow-up, bone healing was satisfactory in all patients. The average postoperative Lysholm score was 91.6 ± 1.4 (range, 84-97). The average postoperative Böstman scale score was 26.4 ± 0.5 (range, 22-30), thereby indicating excellent results in 4 patients and good results in 12. No patients required reoperation.The results demonstrate that this new technique is an effective and safe treatment option for comminuted patella fractures, as it is associated with good clinical outcomes.

Forensic Identification of Bipartite Patella Misdiagnosed as Patella Fracture

Bipartite patella is recognized as a developmental anomaly of ossification. Most of them are asymptomatic and are discovered incidentally. Bipartite patella is sometimes misdiagnosed as a patella fracture, because the x-ray images of both these conditions may appear very similar. In this case, the patient complained of left knee pain after x-ray films revealed a fracture-like line in the left patella. The patient was then diagnosed as having a patella fracture. In China, the injury degree is categorized as serious injury, minor injury, and trivial injury. As the injury degree of patellar fracture is identified as minor injury, the defendant who injured the patient will be sentenced to prison for ≤3 years. However, the defendant objected to this judgment and applied for the second evaluation of injury degree. On the basis of the site of injury, clinical manifestations, and imaging findings, we diagnosed the patient with bipartite patella which belongs to normal anatomic variant. Therefore, the injury degree of the patient was not minor injury.

Patella Fractures Prior to Total Knee Arthroplasty: Worse Outcomes but Equivalent Survivorship

Distal femur and/or tibial plateau fractures adversely affect outcomes of TKA; however it is unknown if a previous patella fracture affects outcome. We reviewed 113 patients undergoing TKA with a previous patella fracture from 1990 to 2012. Component survival was compared to 19,641 patients undergoing TKA for osteoarthritis during the same period. The 15-year implant survivals following a previous patella fracture was 86%. There was no difference in implant survival compared to patients undergoing TKA for OA (P=0.31). Knee society scores significantly improved following TKA; however patients with a fracture had complications related to knee flexion. Patients undergoing primary TKA following a patella fracture have similar overall revision free survival compared to those undergoing TKA for OA at 15-years.

Plasma 25-hydroxyvitamin d levels in operative patella fractures

BACKGROUND

Patella fractures have not traditionally been considered "fragility" fractures.

QUESTIONS/PURPOSE

The purpose of this study was to examine the demographic patterns (age and gender distribution) and plasma 25-hydroxyvitamin D levels of a cohort of patients with operative patella fractures.

PATIENTS AND METHODS

Medical records were reviewed on all consecutive patients presenting to our institution with operative patella fractures from 2003 to 2009. Seventy-eight operative patella fractures (25 male, 53 female) were identified with a mean age of 58 years (range, 22-89 years).

RESULTS

The majority of patients with patella fractures in this series were females over the age of 50 years who sustained low-energy falls from a standing height or less. Twenty-four patients (80%) had vitamin D insufficiency or deficiency at the time of injury. For 68 patients (87%), the patella fracture represented their first fracture. Patients with known osteoporosis risk factors did not have higher rates of vitamin D insufficiency/deficiency.

CONCLUSIONS

The age and gender distribution, as well as the prevalence of vitamin D insufficiency/deficiency, of operative patella fractures, suggest that these patients likely have abnormal vitamin D levels and should undergo a metabolic bone work-up.