Increased Body Mass Index is Associated with Worse Mid- To Long-Term Patient Outcomes after Surgical Repair of Multiligamentous Knee Injuries

We evaluated the relationship between elevated body mass index (BMI) and mid- to long-term outcomes after surgical treatment of multiligamentous knee injury (MLKI). Records identified patients treated surgically for MLKI at a single institution. Inclusion criteria: minimum 2 years since surgery, complete demographics, surgical data, sustained injuries to two or more ligaments in one or both knees, and available for follow-up. Patients were contacted to complete patient-reported outcomes assessments and were classified according to mechanism of injury. Multivariate logistic regression analysis was used to predict the impact of BMI on outcome scores. A total of 77 patients (72.7% male) were included with a mean age at the time of injury of 29.4 ± 11.0 years and a mean BMI of 30.5 ± 9.4 kg/m2. The mean length of follow-up was 7.4 years. For each 10 kg/m2 increase in BMI, there is a 0.9-point decrease in Tegner activity scale (p = 0.001), a 5-point decrease in Knee Injury and Osteoarthritis Outcome Score (KOOS)-pain (p = 0.007), a 5-point decrease in KOOS-ADL (p = 0.003), a 10-point decrease in KOOS-QOL (p = 0.002), and an 11-point decrease in KOOS-Sport (p = 0.002). There were no significant correlations with BMI and Pain Catastrophizing Scale or Patient Health Questionnaire scores. Increasing BMI has a negative linear relationship with mid- to long-term clinical outcomes including pain, ability to perform activities of daily living, quality of life, and ability to perform more demanding physical activity after MLKI. BMI does not appear to have a significant relationship with knee swelling and mechanical symptoms or patients' mental health.

An examination from 1990 to 2019: investigating the burden of knee dislocation on a global scale

Background

The literature on the disease burden of knee dislocation is lacking. The aim of the study is to systematically assess the global burden, trends, causes, and influencing factors of knee dislocation.

Methods

The incidence and years lived with disability (YLDs) of knee dislocation were assessed globally, as well as at the regional and national levels from 1990 to 2019. Subsequent analyses focused on the age and gender distribution related to knee dislocation. An investigation into the main causes of knee dislocation followed. Finally, the Pearson correlation between age-standardized rates and social-demographic index (SDI) was calculated.

Results

Although the age-standardized incidence and YLDs rate of knee dislocation decreased over the past 30 years, the incidence and YLDs number increased. The disease burden remained higher in males compared to females. Males and females showed different patterns of incidence rates in each age group, but their YLDs rates were similar. Over the past 30 years, the disease burden of knee dislocation increased in the older population while declining in the younger population. Falls had consistently emerged as the most important cause for both incidence and YLD rates. Additionally, a positive correlation between SDI and the disease burden of knee dislocation was found.

Conclusion

The disease burden of knee dislocation remains heavy. It is essential to recognize the evolving epidemiology of knee dislocation. Utilizing data-driven assessments can assist in formulating public health policies and strategies to improve overall well-being.

Worse Quality of Life Associated With Hyperextension Varus Tibial Plateau Fracture Pattern

OBJECTIVES

Compare patient-reported outcome measures between hyperextension varus tibial plateau (HEVTP) fracture patterns to non-HEVTP fracture patterns.

METHODS

DESIGN

Retrospective study.

SETTING

Single academic Level 1 Trauma Center.

PATIENT SELECTION CRITERIA

All patients who underwent fixation of a tibial plateau fracture from 2016 to 2021 were collected. Exclusion criteria included inaccurate Current Procedural Terminology code, ipsilateral compartment syndrome, bilateral fractures, incomplete medical records, or follow-up <10 months.

OUTCOME MEASURES AND COMPARISONS

In patients who underwent fixation of a tibial plateau fracture, compare Patient-Reported Outcomes Measurement Information System-Physical Function, PROMIS Preference, and Knee Injury and Osteoarthritis Outcome Score (KOOS) between patients with a HEVTP pattern with those without.

RESULTS

Two-hundred and seven patients were included, of which 17 (8%) had HEVTP fractures. Compared with non-HEVTP fracture patterns, patients with HEVTP injuries were younger (42.6 vs. 51.0, P = 0.025), more commonly male (71% vs. 44%, P = 0.033), and had higher body mass index (32.8 vs. 28.0, P = 0.05). HEVTP fractures had significantly more ligamentous knee (29% vs. 6%, P = 0.007) and vascular (12% vs. 1%, P = 0.035) injuries. Patient-Reported Outcomes Measurement Information System-Physical Function scores were similar between groups; however, PROMIS-Preference (0.37 vs. 0.51, P = 0.017) was significantly lower in HEVTP fractures. KOOS pain, activities of daily living, and quality-of-life scores were statistically lower in HEVTP fractures, but only KOOS quality-of-life was clinically relevant (41.7 vs. 59.3, P = 0.004).

CONCLUSIONS

The HEVTP fracture pattern, whether unicondylar or bicondylar, was associated with a higher rate of ligamentous and vascular injuries compared with non-HEVTP fracture patterns. They were also associated with worse health-related quality of life at midterm follow-up.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Treatment of Knee Dislocation With Primary Repair and Suture Augmentation: A Viable Solution

Background:

Different surgical techniques have been described for the treatment of knee dislocation (KD). Nonoperative approaches are frequently combined with surgical reconstruction using auto- or allograft.

Purpose:

To evaluate the midterm results of primary surgical repair and suture augmentation to treat KD.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 22 patients (5 women, 17 men; mean age, 45 ± 15 years) with KD were evaluated at a mean of 49 ± 16 months after surgical treatment that included primary repair and suture augmentation. Magnetic resonance imaging, stress radiographs, and outcome scores were obtained at the follow-up. Clinical examination including hop tests and force measurements for flexion and extension was performed.

Results:

The mean difference in pre- to postinjury Tegner scores was –2 ± 1. The outcome scores showed mean values of 84 ± 15 (Lysholm), 73 ± 15 (International Knee Documentation Committee) and 65 ± 25 (Anterior Cruciate Ligament–Return to Sport after Injury scale). Compared with the uninjured knee, the range of motion of the injured knee was reduced by 21° ± 12°. Twelve patients felt fit enough to perform hop tests and showed a mean deficit of 7% ± 17%° compared with the uninjured leg. The mean force deficit was 19% ± 18% for extension and 8% ± 16% for flexion. Stress radiographs revealed an 11 ± 7–mm higher anteroposterior translation on the injured side. Four patients had secondary ligament reconstructions due to persistent instability and 7 underwent arthroscopic arthrolysis due to stiffness. A significant increase of osteoarthritis was found for the medial, lateral, and patellofemoral compartments (P = .007, .004, and .006, respectively).

Conclusion:

Primary repair and suture augmentation of KD led to satisfactory clinical midterm results despite persistent radiological instability and a significant increase in osteoarthritis. This technique allows the return to activities of daily living without subjective instability in most nonathletic patients. Secondary ligament reconstructions should be performed if relevant instability persists to decrease the risk of secondary meniscal and cartilage damage.

Predictors Using Machine Learning of Complete Peroneal Nerve Palsy Recovery After Multiligamentous Knee Injury: A Multicenter Retrospective Cohort Study

Background

Peroneal nerve (PN) palsy is one of the most debilitating sequelae of multiligamentous knee injuries (MLKIs). There is limited research on recovery from complete PN palsy.

Purpose/Hypothesis

The purpose of this study was to characterize PN injuries and develop a predictive model of complete PN recovery after MLKI using machine learning. It was hypothesized that elevated body mass index (BMI) would be predictive of lower likelihood of recovery.

Study Design

Case-control study; Level of evidence, 3.

Methods

The authors conducted a retrospective review of patients seen at 2 urban hospital systems for treatment of MLKI with associated complete PN palsy, defined as the presence of complete foot drop with or without sensory deficits on physical examination. Recovery was defined as the complete resolution of foot drop. A random forest (RF) classifier algorithm was used to identify demographic, injury, treatment, and postoperative variables that were significant predictors of recovery from complete PN palsy. Validity of the RF model was assessed using overall accuracy, F1 score, and area under the receiver operating characteristic curve (AUC).

Results

Overall, 16 patients with MLKI with associated complete PN palsy were included in the cohort. Among them, 75% (12/16) had documented knee dislocation requiring reduction. Complete recovery occurred in 4 patients (25%). Nerve contusions on magnetic resonance imaging were more common among patients without PN recovery, but there were no other significant differences between recovery and nonrecovery groups. The RF model found that older age, increasing BMI, and male sex were predictive of worse likelihood of PN recovery. The model was found to have good validity, with a classification accuracy of 75%, F1 score of 0.86, and AUC of 0.64.

Conclusion

The RF model in this study found that increasing age, BMI, and male sex were predictive of decreased likelihood of nerve recovery. While further study of machine learning models with larger patient data sets is required to identify the most superior model, these findings present an opportunity for orthopaedic surgeons to better identify, counsel, and treat patients with MLKIs and concomitant complete PN palsy.

The accuracy of routine knee MR imaging in detection of acute neurovascular injury following multiligamentous knee injury

OBJECTIVE

To assess the accuracy of routine knee MRI in detecting acute popliteal artery and/or common peroneal nerve (CPN) dysfunction following multiligamentous knee injury (MLKI), with correlation of MRI findings to clinical outcome.

MATERIALS AND METHODS

Routine MRI knee examinations in 115 MLKI patients (54/115 with acute neurovascular injury, 61/115 without neurovascular injury) were retrospectively reviewed. Cases were classified by injury mechanism and ligamentous injuries sustained. MRI examinations were reviewed by two readers for vascular (arterial flow void, arterial calibre, intimal flap, perivascular hematoma) and CPN (intraneural T2-hyperintensity, calibre, discontinuity, perineural hematoma) injuries. Accuracy of routine knee MRI in the diagnosis of acute neurovascular injury and correlation of MRI findings to clinical outcome were evaluated.

RESULTS

Patients included 86/115 males, mean age 33 years. The accuracy of MRI in diagnosis of acute CPN injury was 80.6%, 83.6% (readers 1 and 2): sensitivity (78%, 79.7%), specificity (80%, 86.7%), PPV (78%, 82.5%), and NPV (82.7%, 84.4%). Increased intraneural T2 signal showed a significant correlation to acute CPN dysfunction (p < 0.05). MRI was 75%, 69.8% (readers 1 and 2) accurate in detecting acute vascular injury: sensitivity (73.3%, 86.7%), specificity (75.2%, 67.3%), PPV (30.5%, 36.1%), and NPV (95%, 97.1%). No MRI features of vascular injury showed a statistical correlation with clinical outcome. Neurovascular complications were more common in ultra-low-energy injuries and KD-V3L pattern of ligament disruption.

CONCLUSION

Routine MRI is of limited accuracy in assessing vascular complication, but higher accuracy in assessing CPN injury following MLKI. Increased intraneural T2 signal on conventional knee MR imaging shows statistically significant association with clinically documented acute CPN dysfunction following MLKI.

Demographic analysis of knee dislocation: A rare mechanism of injury

PURPOSE

The aim of this study was to present to the literature a rare injury mechanism that causes knee dislocation (KD) and describe its characteristics.

METHODS

A retrospective review of patients with KD who were treated between January 2014 and December 2019 at our hospital was performed. Patients with KD due to rotavator machine injury were included in Group 1 and all patients with KD due to other etiological reasons were included in Group 2. Patients' age, gender, side, injury mechanism, time to surgery, length of stay (LOS), operation time, follow-up time, neurological injury status, vascular injury status, open injury status, and surgical interventions were evaluated.

RESULTS

A total of 34 patients were evaluated in the study. There was no statistically significant difference between the groups in terms of age, gender, side, or follow-up time (p = .915, p = 1.000, p = .682, p = .374, respectively). However, LOS and time to surgery were statistically significantly longer in Group 1 (p = .037, p = .010, respectively). Moreover, neurovascular damage was statistically significantly more common in Group 1.

CONCLUSION

As a rare injury mechanism for KD, rotavator machine injuries cause more neurovascular injuries in patients compared to other injury mechanisms and increase the time to surgery and LOS due to preoperative soft tissue damage.

Knee Dislocations in the Morbidly Obese Patient

Ultra-low-velocity knee dislocations are historically rare but increasingly common events. They occur most frequently in obese, morbidly obese, and super obese patients during everyday activities, but they can be as severe or more severe than high-velocity knee dislocations. Ultra-low-velocity knee dislocations frequently are associated with neurovascular injury and other complications. Diagnosis, early reduction, and identification and treatment of vascular injuries are critical to reducing the risk of limb ischemia and possibly amputation. Given the size of the limb, maintenance of reduction in these patients almost always requires external fixation. Although surgery on morbidly obese patients may be technically challenging, surgical reconstruction leads to improved subjective and objective results and is recommended.

Which Risk Factors Predict Knee Ligament Injuries in Severely Injured Patients?-Results from an International Multicenter Analysis

Introduction: Ligament injuries around the knee joint and knee dislocations are rare but potentially complex injuries associated with high-energy trauma. Concomitant neurovascular injuries further affect their long-term clinical outcomes. In contrast to isolated ligamentous knee injuries, epidemiologic data and knowledge on predicting knee injuries in severely injured patients is still limited. Methods: The TraumaRegister DGU^® (TR-DGU) was queried (01/2009–12/2016). Inclusion criteria for selection from the database: maximum abbreviated injury severity ≥ 3 points (MAIS 3+). Participating countries: Germany, Austria, and Switzerland. The two main groups included a “control” and a “knee injury” group. The injury severity score (ISS) and new ISS (NISS) were used for injury severity classification, and the abbreviated injury scale (AIS) was used to classify the severity of the knee injury. Logistic regression analysis was performed to evaluate various risk factors for knee injuries. Results: The study cohort included 139,462 severely injured trauma patients. We identified 4411 individuals (3.2%) with a ligament injury around the knee joint (“knee injury” group) and 1153 patients with a knee dislocation (0.8%). The risk for associated injuries of the peroneal nerve and popliteal artery were significantly increased in dislocated knees when compared to controls (peroneal nerve from 0.4% to 6.7%, popliteal artery from 0.3% to 6.9%, respectively). Among the predictors for knee injuries were specific mechanisms of injury: e.g., pedestrian struck (Odds ratio [OR] 3.2, 95% confidence interval [CI]: 2.69–3.74 p ≤ 0.001), motorcycle (OR 3.0, 95% CI: 2.58–3.48, p ≤ 0.001), and motor vehicle accidents (OR 2.2, 95% CI: 1.86–2.51, p ≤ 0.001) and associated skeletal injuries, e.g., patella (OR 2.3, 95% CI: 1.99–2.62, p ≤ 0.001), tibia (OR 1.9, 95% CI: 1.75–2.05, p ≤ 0.001), and femur (OR 1.8, 95% CI: 1.64–1.89, p ≤ 0.001), but neither male sex nor general injury severity (ISS). Conclusion: Ligament injuries and knee dislocations are associated with high-risk mechanisms and concomitant skeletal injuries of the lower extremity, but are not predicted by general injury severity or sex. Despite comparable ISS, knee injuries prolong the hospital length of stay. Delayed or missed diagnosis of knee injuries can be prevented by comprehensive clinical evaluation after fracture fixation and a high index of suspicion is advised, especially in the presence of the above mentioned risk factors.

Osteochondral Fracture of Posterior Aspect of Lateral Femoral Condyle After Lateral Patella Dislocation: A Case Report

CASE

A healthy 15-year-old girl presented with osteochondral fracture at the posterior aspect of the lateral femoral condyle (LFC) associated with a right patellar dislocation after a noncontact injury. The patient remained asymptomatic 18 months after the arthroscopically assisted reduction and internal fixation of the osteochondral fracture using bioabsorbable pins and was able to eventually resume her usual activities of daily living.

CONCLUSIONS

This is the first report of an osteochondral fracture at the posterior aspect of the LFC after an acute patellar dislocation, successfully treated with arthroscopically assisted reduction and internal fixation using bioabsorbable pins. This rare injury and unique mechanism of injury have been discussed.

Knee dislocation and associated injuries: an analysis of the American College of Surgeons National Trauma Data Bank

PURPOSE

Knee dislocations (KDs) are potentially devastating injuries, leading to loss of function or limb in often young patients. This retrospective database review aims to determine the relative incidence and risk factors for KDs presenting to North American Level I and II trauma centers.

METHODS

The National Trauma Data Bank (NTDB) was retrospectively interrogated using ICD-9-CM codes to identify KDs between 2010 and 2014 to derive KD incidence. KDs were stratified by age, sex, Injury Severity Score (ISS), Glasgow Coma Scale (GCS), drug and alcohol use, injury mechanism, open vs. closed KD, vascular injury and fracture. Each co-variate was tested against different mechanisms of injury, using Chi-squared tests and risk adjusted analyses to derive risk factors for KD. The same calculations were done for secondary outcomes (vascular and neurological injuries, compartment syndrome, amputation, and mortality).

RESULTS

A total of 6454 KDs met the inclusion criteria (18/10,000 admissions). KDs occurred most commonly amongst men, aged 20-39, with an ISS score 1-14 and following motor vehicle collision (MVC). A vascular investigation was performed in 29%, with injury documented in 15% of KDs and 10.8% receiving a vascular procedure. Associated fractures were observed in 41.4% of KDs. Open injuries in 13.6%. Neurological injury documented in 6.2%, compartment syndrome in 2.7%, amputation in 3.8% (> 50% had vascular injury) and 2.8% died. MVC was the most common mechanism of injury (p < 0.001), significantly more common in young, male patients, associated with higher ISS and lower GCS, especially when drugs or alcohol were involved (p < 0.0001). Being male, having a vascular injury or open KD were all risk factors for compartment syndrome, amputation and neurological injuries.

CONCLUSIONS

KDs are rare injuries, but their relative incidence may be increasing. Young, male patients involved in MVCs are risk factors for KDs and their associated injuries, such as neurological injuries, amputations and compartment syndrome. Vascular injury occurs at a frequency of around 15%. The findings of the current study may guide future research and help to inform clinicians on the expected rates of associated injuries in patients identified to have KD in a trauma center population. It informs regarding risk factors for KD, which may improve diagnosis rates of spontaneously reduced knee dislocations by increasing index of suspicion in high-risk patients and identifies specific links with impaired driving.

LEVEL OF EVIDENCE

IV.

Risk of knee osteoarthritis after different types of knee injuries in young adults: a population-based cohort study

Objectives

To estimate the risk of clinically diagnosed knee osteoarthritis (OA) after different types of knee injuries in young adults.

Methods

In a longitudinal cohort study based on population-based healthcare data from Skåne, Sweden, we included all persons aged 25–34 years in 1998–2007 (n=149 288) with and without diagnoses of knee injuries according to International Classification of Diseases (ICD)-10. We estimated the HR of future diagnosed knee OA in injured and uninjured persons using Cox regression, adjusted for potential confounders. We also explored the impact of type of injury (contusion, fracture, dislocation, meniscal tear, cartilage tear/other injury, collateral ligament tear, cruciate ligament tear and injury to multiple structures) on diagnosed knee OA risk.

Results

We identified 5247 persons (mean (SD) age 29.4 (2.9) years, 67% men) with a knee injury and 142 825 persons (mean (SD) age 30.2 (3.0) years, 45% men) without. We found an adjusted HR of 5.7 (95% CI 5.0 to 6.6) for diagnosed knee OA in injured compared with uninjured persons during the first 11 years of follow-up and 3.4 (95% CI 2.9 to 4.0) during the following 8 years. The corresponding risk difference (RD) after 19 years of follow-up was 8.1% (95% CI 6.7% to 9.4%). Cruciate ligament injury, meniscal tear and fracture of the tibia plateau/patella were associated with greatest increase in risk (RD of 19.6% (95% CI 13.2% to 25.9%), 10.5% (95% CI 6.4% to 14.7%) and 6.6% (95% CI 1.1% to 12.2%), respectively).

Conclusion

In young adults, knee injury increases the risk of future diagnosed knee OA about sixfold with highest risks found after cruciate ligament injury, meniscal tear and intra-articular fracture.

Knee and Leg Injuries

Knee and leg injuries are extremely common presentations to the emergency department. Understanding the anatomy of the knee, particularly the vasculature and ligamentous structures, can help emergency physicians (EPs) diagnose and manage these injuries. Use of musculoskeletal ultrasonography can further aid EPs through the diagnostic process. Proper use of knee immobilizers can also improve long-term patient outcomes.

Importance of Early Diagnosis and Care in Knee Dislocations Associated with Vascular Injuries

BACKGROUND

Arterial injury secondary to acute knee dislocation (KD) is a rare but devastative complication. The aim of this study is to evaluate functional sequelae and factors of poor prognosis.

METHODS

A retrospective monocentric series of consecutive KD with acute ischemia by popliteal artery injury was analyzed between 2005 and 2017. The main outcome was the amputation rate.

RESULTS

Sixteen dislocations were included. Nine (56%) were due to public road accidents, 5 (31%) were due to falls from height, and 2 (13%) were due to sports injuries. Dislocation had occurred in the posterior location in 8 (50%) cases. Regarding arterial injury, there were 7 (44%) ruptures, 7 (44%) dissections, and 2 (13%) isolated thromboses. Eleven (69%) KDs with vascular trauma were associated with signs of acute ischemia. Revascularization was achieved by anatomical venous bypass in 14 (88%), resection and direct anastomosis in one (6%), and isolated thrombectomy in one (6%). Median time to surgery (time between trauma and vascular repair) was 7 hours (3.25-60.92 hours). Primary revascularization was performed in 12 (75%) cases. In three cases (19%), orthopedic reduction and stabilization were performed first. In one case, (6%) three-step management with vascular shunt at first, then with knee stabilization, and finally vascular bypass was carried out. Stabilization was achieved by using an external fixator in 13 (82%) cases, by open reduction and internal fixation in one case (6%), by ligamentoplasty in one (6%), and by using a long leg cast in one (6%). Fasciotomy was required in 12 (75%) cases. Two patients had early vascular complications, and 2 had early systemic complications. Three secondary transfemoral amputations were performed. Median follow-up duration was 23 months. No secondary amputation was recorded. At the end of follow-up, functional outcomes were evaluated using the Oxford Knee Score (OKS). The median OKS was 30 versus the pretrauma median OKS of 47 (P < 0.00028). No risk factor associated with limb amputation has been highlighted.

CONCLUSIONS

Analysis of these results provided indications for therapeutic management of this condition. This study shows poor functional outcomes because of severity of vascular lesion in patients with orthopedic trauma but with healthy arteries.

Simultaneous Bilateral Knee Dislocation During Weight Training: A Case Report and Review of the Literature

CASE

We describe the clinical course and treatment of a patient who sustained simultaneous bilateral knee dislocation under low-velocity atraumatic conditions, and provide a review of the literature. Dislocations of the native knee joint are uncommon orthopaedic injuries but they are true emergencies because of the concern for concomitant neurovascular injury; therefore, they may be limb-threatening injuries.

CONCLUSION

To our knowledge, there are few reports of simultaneous bilateral knee dislocation and no reports of this occurring during weight training. The risk of knee dislocation can be reduced by avoiding locking and hyperextension of the knees during any type of leg press or squatting exercise.

"Multiligamentous" Injuries of the Skeletally Immature Knee: A Case Series and Literature Review

Multiligamentous knee injuries occur rarely in the pediatric population. Few reports are available in the existing literature; furthermore, no longitudinal studies regarding the choice of treatment and long-term outcomes for this unique population have been published. To fill this knowledge gap, the literature on multiligamentous injuries of the knee in the adult population is commonly used as a guideline in clinical decision making for children and adolescents. However, the developing bone and physis are often weaker than the ligamentous structures of the knee—particularly during periods of rapid growth—and may be the first to fail in the event of injury or trauma. Bony avulsion fractures and peri-physeal fractures, rather than mid-substance ligamentous ruptures, may result. Patients with skeletal immaturity may therefore present with different patterns of multiligamentous injury after acute trauma to the knee. This article describes the clinical presentation, our treatment approach, and short-term outcomes for three pediatric patients with multiligamentous injuries of the knee and reviews the current literature relating to these uncommon injuries.

Diagnostic and Management Strategies for Multiligament Knee Injuries: A Critical Analysis Review

Multiligament knee injuries have a strong association with periarticular soft-tissue and neurovascular injuries, which must not be overlooked in the initial evaluation of the patient. Even though magnetic resonance imaging (MRI) is imperative for a complete evaluation of the damaged ligamentous knee restraints, stress radiography aids in establishing the functional consequence of the MRI findings and may assist in directing reconstruction. Although cruciate ligament tears are generally reconstructed, a combined repair-reconstruction approach is most useful for collateral ligaments and extra-articular structures, with incorporation of local tissue into the reconstruction whenever possible. Regardless of the timing and operative technique chosen, patients with multiligament knee injuries are at high risk for complications and long-term disability.

Knee dislocation with popliteal artery disruption: A nationwide analysis from 2005 to 2013

Objective

Few have compared short-term outcomes following knee dislocations with or without concomitant popliteal artery disruption (PAD).

Methods

The Nationwide Inpatient Sample was used to identify 2175 patients admitted for knee dislocation from 2005 to 2013 (concomitant PAD: n = 210/9.7%; without: n = 1965/90.3%).

Results

Patients with PAD were younger, more often male, Black and Hispanic, and with Medicaid (all p ≤ 0.013). PADs were associated with 11.0-times higher odds of increased LOS (95%CI, 6.6-18.4) and 2.8-times higher odds of experiencing any complication (95%CI, 2.03-3.92). Female sex was a protective factor against increased LOS, (OR = 0.65; 95%CI, 0.48-0.88).

Conclusion

High suspicion index should be maintained for concomitant vascular injuries following knee dislocations.

Obesity in the Polytrauma Patient

The rates of obesity continue to increase in the United States and the overall impact of obesity on health care spending and patient outcomes after trauma is considerable. The unique physiology of the obese places them at higher risk for complications, including infection, failure of fixation, nonunion, multiorgan failure, and death. These physiologic differences and overall patient size can make orthopedic care in obese patients with trauma more difficult, but appropriate initial resuscitation, careful preoperative planning, meticulous surgical technique, diligent postoperative medical management, and specialized rehabilitation give these patients their best opportunity for a good outcome.

Increased Incidence of Vascular Injury in Obese Patients With Knee Dislocations

OBJECTIVES

With rising rates of obesity in the United States, the burden of knee dislocations in this population remains unknown. This national epidemiologic study was designed to analyze the association of obesity with closed knee dislocation and vascular complications.

DESIGN

Retrospective cohort study.

SETTING

The deidentified Nationwide Inpatient Sample database was used to access the US inpatient data from 2000 to 2012.

PATIENTS/PARTICIPANTS

Patients with noncongenital closed knee dislocations were included. Examined variables included patient age, sex, vascular injury, and obesity status.

MAIN OUTCOME MEASURES

Outcome measures included hospital length of stay, amputation, and inpatient hospitalization charge.

RESULTS

From 2000 to 2012, a total of 19,087 knee dislocations were identified, including 2265 in overweight/obese patients (11.9%). The annual incidence of knee dislocations reported in patients diagnosed as either obese or morbidly obese increased over the 13-year period (P < 0.0001). The overall average rate of vascular injury requiring intervention was 5.63%, whereas 7.2% of obese patients and 11.3% of morbidly obese patients with knee dislocations (P < 0.0001) sustained a vascular injury requiring intervention. The average length of stay and amputation rate for obese and morbidly obese patients who sustained a knee dislocation was not statistically different from nonobese patients when vascular injury was controlled. When patients with a vascular injury were excluded, obese and morbidly obese patients who sustained a knee dislocation had higher average cost of hospital stay than nonobese patients (P = 0.0262).

CONCLUSIONS

This study demonstrates significant increases in costs of stay with obese patients sustaining knee dislocations when compared with normal weight knee dislocation patients. Vascular injuries were found to be far more common in obese and morbidly obese patient groups than nonobese patients. Providers should be on high alert when managing knee dislocations in obese patients because a significant number require prompt vascular intervention.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

The role of MRI in understanding the underlying mechanisms in obesity associated diseases

Obesity and its possible association with diseases including diabetes and cardiovascular diseases have been studied for decades for its impact on healthcare. Recent studies clearly indicate the need for developing accurate and reproducible methodologies for assessing body fat content and distribution. Body fat distribution plays a significant role in developing an insight in the underlying mechanisms in which adipose tissue is linked with various diseases. Among imaging technologies including computerized axial tomography (CAT or CT), magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS), MRI and MRS seem to be the best emerging techniques and together are being considered as the gold standard for body fat content and distribution. This paper reviews studies up to the present time involving different methodologies of these two emerging technologies and presents the basic concepts of MRI and MRS with required novel image analysis techniques in accurate, quantitative, and direct assessment of body fat content and distribution. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.

Acute Management of Traumatic Knee Dislocations for the Generalist

Acute knee dislocations are an uncommon injury that can result in profound consequences if not recognized and managed appropriately on presentation. Patients presenting with knee pain in the setting of high- or low-energy trauma may have sustained a knee dislocation that spontaneously reduced. Prompt reduction of the dislocated knee and serial neurovascular examinations are paramount. Damage to the popliteal artery is a common associated injury that can be diagnosed on physical examination using ankle brachial indices (ABIs), CT angiography, or standard angiography. After reduction, patients with a normal pulse examination and an ABI ≥0.9 may be observed, with serial examination performed to document vascular status and monitor for compartment syndrome. Patients with asymmetric pulses or an ABI <0.9 in the presence of pulses may be treated urgently depending on the results of additional vascular imaging, and patients with absent pulses and clear signs of vascular compromise should be treated emergently. Some knee dislocations are not reducible and should be taken emergently to the operating room for an open reduction. Persistent joint subluxation or severe soft-tissue injuries after reduction require temporary external fixation before definitive repair or reconstruction of ligaments is performed.

Multiligamentous injuries and knee dislocations

Complex capsular ligamentous structures contribute to stability of the knee joint. Simultaneous injury of two or more knee ligaments, aside from concurrent tears involving the anterior cruciate and medial collateral ligaments, is considered to be associated with femorotibial knee dislocations. Proximal tibiofibular joint dislocations are not always easily recognized and may be overlooked or missed. Patellofemoral dislocations can be transient with MR imaging sometimes required to reach the diagnosis. In this article, the authors describe the mechanism of injury, ligamentous disruptions, imaging, and treatment options of various types of knee dislocations including injuries of the femorotibial, proximal tibiofibular, and patellofemoral joints.

Surgical treatment of multiligament knee injuries

PURPOSE

To analyse one institution's experience with multiligament knee injuries.

METHODS

Over 10 years, 133 multiligament knee injuries including 130 patients were included in the study. Inclusion criteria included: (1) injury to two or more knee ligaments (2) multiligament knee repair/reconstructive surgery.

RESULTS

The average age at time of injury was 26 years old, and 76 % were male. Fifty-one (38 %) multiligament knee injuries had >2 ligaments injured. Peroneal injuries occurred in 26 patients (20 %), and four (3 %) had associated vascular injuries. A high energy mechanism of injury was noted in 39 %. Twenty-five per cent of patients had an additional orthopaedic injury and, 11.5 % suffered additional non-orthopaedic injuries. Definitive surgical intervention was performed acutely (<3 weeks) in 47 %. Ninety-one per cent of multiligament knee injuries underwent reconstruction with or without repair. Forty-three complications occurred in 37 patients. Patients who suffered >2 ligament injury or had surgery acutely were at an increased risk of knee stiffness requiring manipulation under anaesthesia (MUA) (p = 0.016 and p = 0.047, respectively). Knees with >2 ligaments injured were associated with higher post-operative complications (p = 0.007). Knee dislocation IV knees were at increased risk to undergo revision surgery (p = 0.041). Obese patients were more likely to have a post-operative infection (p = 0.038). Repair, reconstruction or type of graft used had no impact on need for revision surgery.

CONCLUSIONS

Multiligament knee injured patients undergoing surgical intervention are a highly complex patient population. This study outlines the patient population, treatment, and complications of one academic institution over 10 years. Overall complications were higher in patients with >2 ligaments injured. Knee stiffness requiring MUA was more common in patients who had >2 ligaments ruptured and those treated acutely. Knees with all four ligaments injured were more likely to undergo revision surgery.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

A systematic review of peroneal nerve palsy and recovery following traumatic knee dislocation

PURPOSE

A common peroneal nerve (CPN) palsy has been reported to complicate knee dislocations in 5-40 % of patients. Patients who suffer from a persistent foot drop have significantly worse functional outcomes. Reports on prognostic factors for nerve recovery or treatment-specific functional outcomes remain sparse in the literature.

METHODS

Two independent reviewers completed a search of Medline, Embase, PubMed and the Cochrane Library from 1946 to present. Motor strength was determined using the Medical Research Council (MRC) grading system or an equivalent description. A functional recovery was defined as an MRC ≥3/5.

RESULTS

The combined search of Medline, Embase, PubMed and the Cochrane Library identified 1528 abstracts. Thirteen articles met our inclusion/exclusion criteria. This included 214 CPN palsies. Functional recovery (MRC ≥3/5) following complete CPN palsy was 38.4 %. Full recovery (MRC = 5/5) following partial CPN palsy was 87.3 %. Younger age was predictive of neurologic recovery. Recovery following isolated neurologic interventions ranged from 0 to 30 %.

CONCLUSIONS

A vastly different prognosis can be expected for patients who suffer an incomplete versus a complete CPN palsy. The majority of patients with an incomplete palsy will achieve a full motor recovery while <40 % of patients with a complete motor palsy will regain the ability to dorsiflex at the ankle. While neurologic interventions show promise for the future, the outcomes in knee dislocation patients remain poor. The most predictable means of reestablishing antigravity dorsiflexion in a persistent CPN palsy is a posterior tibial tendon transfer.

Combined common peroneal and tibial nerve injury after knee dislocation: one injury or two? An MRI-clinical correlation

OBJECT

Knee dislocations are often accompanied by stretch injuries to the common peroneal nerve (CPN). A small subset of these injuries also affect the tibial nerve. The mechanism of this combined pattern could be a single longitudinal stretch injury of the CPN extending to the sciatic bifurcation (and tibial division) or separate injuries of both the CPN and tibial nerve, either at the level of the tibiofemoral joint or distally at the soleal sling and fibular neck. The authors reviewed cases involving patients with knee dislocations with CPN and tibial nerve injuries to determine the localization of the combined injury and correlation between degree of MRI appearance and clinical severity of nerve injury.

METHODS

Three groups of cases were reviewed. Group 1 consisted of knee dislocations with clinical evidence of nerve injury (n = 28, including 19 cases of complete CPN injury); Group 2 consisted of knee dislocations without clinical evidence of nerve injury (n = 19); and Group 3 consisted of cases of minor knee trauma but without knee dislocation (n = 14). All patients had an MRI study of the knee performed within 3 months of injury. MRI appearance of tibial and common peroneal nerve injury was scored by 2 independent radiologists in 3 zones (Zone I, sciatic bifurcation; Zone II, knee joint; and Zone III, soleal sling and fibular neck) on a severity scale of 1–4. Injury signal was scored as diffuse or focal for each nerve in each of the 3 zones. A clinical score was also calculated based on Medical Research Council scores for strength in the tibial and peroneal nerve distributions, combined with electrophysiological data, when available, and correlated with the MRI injury score.

RESULTS

Nearly all of the nerve segments visualized in Groups 1 and 2 demonstrated some degree of injury on MRI (95%), compared with 12% of nerve segments in Group 3. MRI nerve injury scores were significantly more severe in Group 1 relative to Group 2 (2.06 vs 1.24, p < 0.001) and Group 2 relative to Group 3 (1.24 vs 0.13, p < 0.001). In both groups of patients with knee dislocations (Groups 1 and 2), the MRI nerve injury score was significantly higher for CPN than tibial nerve (2.72 vs 1.40 for Group 1, p < 0.001; 1.39 vs 1.09 for Group 2, p < 0.05). The clinical injury score had a significantly strong correlation with the MRI injury score for the CPN (r = 0.75, p < 0.001), but not for the tibial nerve (r = 0.07, p = 0.83).

CONCLUSIONS

MRI is highly sensitive in detecting subclinical nerve injury. In knee dislocation, clinical tibial nerve injury is always associated with simultaneous CPN injury, but tibial nerve function is never worse than peroneal nerve function. The point of maximum injury can occur in any of 3 zones.

Effect of body mass index on patients with multiligamentous knee injuries

PURPOSE

Our goal was to evaluate the impact of body mass index (BMI) on complications and associated injuries in patients undergoing surgical treatment for multiligamentous knee injuries (MLKIs).

METHODS

Over a period of 10 years, 126 MLKIs (123 patients) were included in the study. The inclusion criteria were (1) injury to 2 or more knee ligaments, (2) multiligament repair and/or reconstruction performed by 1 of 3 sports medicine orthopaedic surgeons at our institution, and (3) minimum of 1 year of follow-up. A chart review was performed to collect demographic data, mechanism of injury, ligaments involved, complications, and associated neurovascular injuries. Lastly, patients were divided by BMI into non-obese (<30 kg/m(2)) and obese (≥30 kg/m(2)) groups.

RESULTS

Of the 126 MLKIs, 87 occurred in non-obese patients and 39 occurred in obese patients. Surgical complication rates for non-obese and obese patients were 8.05% and 15.4%, respectively (P = .21). Revisions were needed in 8.05% and 5.1% of patients in these groups, respectively (P = .72). Three wound complications were found in the obese group only. Vascular injuries were found in 2.3% and 7.7% of patients in the non-obese and obese groups, respectively (P = .17). The rates of nerve injuries were 11.49% and 20.51%, respectively (P = .18). Patients in the obese group were most likely to have an MLKI from low-energy mechanisms, disregarding sports-related injuries (51.28%, P = .02). Using a logistic model and BMI as a continuous variable, we found that a 1-unit increase in BMI increased the odds ratio of complications by 9.2%, with statistical significance (P = .0174). In addition, post hoc power analysis using previous literature showed that this study could produce satisfactory power.

CONCLUSIONS

Our results indicate that (1) obese individuals are significantly more likely to have an MLKI caused by low-energy mechanisms and (2) complication rates increase by 9.2% for every 1-unit increase in BMI.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The changing demographics of knee dislocation: a retrospective database review

BACKGROUND

Knee dislocations are uncommon but devastating orthopaedic injuries. Little is known about their frequency and the types of patients who are affected.

QUESTIONS/PURPOSES

Using a large national insurance database, we determined (1) the incidence of knee dislocation in patients with orthopaedic injuries and examined the incidence as a function of (2) year of diagnosis, (3) dislocation type (open versus closed, direction), and (4) patient demographic factors (sex, age).

METHODS

We searched the PearlDiver database, a national database of private insurance records consisting of 11 million patients with orthopaedic diagnoses, using diagnosis (ICD-9-CM) codes for knee dislocation between the years 2004 and 2009. The PearlDiver database does not include Medicare, Medicaid, or uninsured patients. Patients were stratified by age, sex, and year of diagnosis. Incidence was defined as the number of dislocation events per 100 patient-years.

RESULTS

We identified 8050 dislocations, representing an incidence of 0.072 events per 100 patient-years between 2004 and 2009. Annual dislocation incidence did not increase during the 6-year study period. Of the 8050 dislocations, 1333 (17%) were open and 6717 (83%) were closed, representing an incidence of 0.060 per 100 for closed dislocations and 0.012 per 100 for open dislocations. The most common direction of dislocation was unspecified or other (65%), followed by anterior (13%), lateral (11%), posterior (6%), and medial (5%). Of the patients sustaining dislocations, 4172 (52%) were female and 3878 (48%) were male. Males displayed an increased risk of knee dislocation compared to females (odds ratio = 1.09). The mean patient age was 35 years, and patient age was inversely correlated to the incidence of knee dislocation (10-year odds ratio = 0.77).

CONCLUSIONS

Our data suggest that knee dislocation might represent a significantly larger burden among orthopaedic injuries than previously thought. The finding that males and females have a nearly equal risk of knee dislocation enhances the diagnosing physician's clinical suspicion of this injury. Future large prospective studies analyzing the various causes of knee dislocation could provide insight into the changing demographics of this injury.

LEVEL OF EVIDENCE

Level IV, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

Ultra-low velocity knee dislocations: patient characteristics, complications, and outcomes

BACKGROUND

Knee dislocations resulting in multiligament knee injuries (MLIs) are usually associated with high-energy mechanisms such as motor vehicle accidents or sports injuries; however, obese patients are at risk of MLIs from simple falls. Termed "ultra-low velocity" (ULV) dislocations, these injuries occur in obese patients during activities of daily living and may be associated with higher associated risks and complications.

HYPOTHESIS

Ultra-low velocity knee dislocations occur more commonly in obese female patients, are associated with higher risks of neurovascular injuries, and have more significant perioperative complications compared with other MLIs.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The records of 215 consecutive patients with MLIs were identified over a 12-year period. Their charts were reviewed to identify a cohort of patients with mechanisms consistent with ULV dislocations (n = 23). This cohort was compared with all patients with MLIs. Additionally, ULV patients with neurovascular injuries were compared with those without neurovascular injuries.

RESULTS

The average body mass index (BMI) was significantly higher in the ULV cohort (49.1 kg/m2) compared with all patients with MLIs (34.1 kg/m2). Injuries occurred more commonly in female patients in the ULV cohort (69.6%) compared with all patients with MLIs (24.3%). Peroneal nerve injuries occurred more commonly in the ULV cohort (39.1%) compared with all patients with MLIs (8.4%), as did vascular injuries (28.1% vs. 4.7%, respectively). Postoperative complications were common among all ULV-MLI patients regardless of neurovascular injury status. Seventeen patients (6/12 in the intact group and 11/11 in the neurovascular injury group) had significant complications postoperatively. A significantly higher overall complication rate was noted in the ULV-MLI group (73.9%) compared with the entire MLI cohort (21.4%). Additionally, the ULV-MLI cohort had a higher reoperation rate, wound infection rate, deep venous thrombosis rate, and presence of vascular claudication.

CONCLUSION

Ultra-low velocity knee injuries occur in patients with a greater BMI, more frequently in female patients, and with higher rates of concomitant neurovascular injuries compared with other MLIs. Additionally, a significantly greater incidence of postoperative complications can be expected after ligament reconstruction in this population compared with other MLIs.

Radiologic review of knee dislocation: from diagnosis to repair

OBJECTIVE

This imaging-based article systematically reviews traumatic knee dislocations. After completion, the reader should be familiar with the definition, epidemiology, cause, and classification schemes associated with these injuries, as well as the importance of timely diagnostic imaging and an accurate, detailed description of findings, particularly as it relates to MRI interpretation. Finally, information our orthopedic surgical colleagues consider critical for the preoperative planning and reconstruction of the multiple ligament knee injury will be discussed.

CONCLUSION

Although uncommon, traumatic knee dislocations are an important potentially limb-threatening injury, which if not emergently recognized and appropriately managed, can result in significant patient morbidity, joint dysfunction, chronic pain, and long-term disability. A radiologist familiar with the imaging appearance and potential neurovascular complications associated with these injuries can play an integral role in the multidisciplinary team that manages this increasingly recognized clinical entity.

Staged management of knee dislocation in polytrauma injured patients

INTRODUCTION

Knee dislocation in the polytrauma setting is rare. The optimal method that this injury should be managed remains controversial. We therefore undertook a study to evaluate the incidence and outcomes of knee dislocation in polytrauma patients treated in our institution.

PATIENTS AND METHODS

From January 2005 to February 2011, two hundred-seventy five polytrauma patients were managed in our institution. Knee dislocation was present in 14 patients (4%): 4 females, mean age 46 years (range 19-52), mean ISS 24 (range 18-34) and 10 males, mean age 45 years (18-48), mean ISS 28 (range 18-48). Knee dislocation was classified according to the Schenck classification. MRI was used routinely for accurate assessment of the knee lesions. Treatment protocol consisted of initially management with the ATLS guidelines, neurovascular assessment, emergency surgical care simultaneously with reanimation procedures and hospitalization at ICU. Upon full evaluation and stabilization of the patient's physiological status and acquisition of a knee MRI scan, one- to three-stage operative treatment was performed. Decision for one- or more-stage treatment was based on the evaluation of the systemic and local clinical status, injury classification, timing of surgery, and consequences that remained after associated injuries. Clinical outcome was evaluated by IKDC 2000 Subjective knee evaluation, IKDC Clinical Examination Scales and the Tegner-Lysholm scale. A specific accelerated rehabilitation program was completed according to the surgical treatment. The mean follow up was 2 years (range 19-48 months).

RESULTS

Patients had a different type of knee dislocations: five KD II, six KD III, two KD V2 and one KD V3. Clinical results were low in patients that underwent the three-staged protocol, and good and high in one- or two-staged operative treatment respectively at the two year follow up. The difference between the results in three groups of treated patients was visible but not statistically significant.

CONCLUSION

The physiological state of the patient along with the type of knee lesion dictates a timing and type of stage treatment. The best postoperative clinical results are fulfilled with the one-stage treatment and it should be the first choice of knee dislocation therapy. Two-stage treatment should be performed only if the general clinical status of polytrauma injured patient or local knee status does not allow a complete knee reconstructive surgery. Three-stage treatment results with the worst outcome and it should be avoided.

Orthopedic trauma surgery in the morbidly obese patient

PURPOSE

The treatment of morbidly obese patients in orthopedic trauma differs in many ways compared to injured patients with normal body mass indices. This paper highlights key differences and ways to overcome obstacles.

METHODS

We present specific tips, as well as considerations for initial planning, positioning for surgery, intra-operative strategies, and a discussion on both anesthesia and imaging.

RESULTS

Several treatment strategies have been shown to have better results in morbidly obese patients. Pre-operative planning is necessary for minimizing risk to the patient.

CONCLUSION

The prevalence of morbid obesity has increased in the USA in the past quarter century. Treatment for orthopedic injuries in morbidly obese patients requires a multidisciplinary approach that addresses not only their orthopedic injuries, but also medical co-morbidities. A team of medicine doctors, anesthesiologists, X-ray technicians, physical and occupational therapists, respiratory therapists, and social workers is needed in addition to the orthopedic surgeon. Modifications in both pre-operative planning and intra-operative strategies may be necessary in order to accommodate the patient. This paper presents numerous technical tips that can aid in providing stable fixation for fractures, as well as addressing peri-operative issues specific to the morbidly obese.

Investigation of multiligamentous knee injury patterns with associated injuries presenting at a level I trauma center

OBJECTIVES

To characterize multiligamentous knee injury patterns and describe associated morbidities.

DESIGN

Retrospective.

SETTING

Level I trauma center.

PATIENTS

One hundred two patients (106 knees) with multiligamentous knee injuries and/or dislocations from 2000 through 2008. Subgroup of 82 knees with appropriate magnetic resonance images available assessed for ligamentous injury patterns.

INTERVENTION

Data obtained from medical records for 106 knees.

MAIN OUTCOME MEASUREMENTS

Presence of arterial injuries, nerve injuries, associated fracture patterns, and whole-body morbidities.

RESULTS

The most common (43%) injury pattern was a combined disruption of the anterior cruciate ligament, posterior cruciate ligament, and posterolateral corner. Twenty-five percent of knees had associated ipsilateral tibial plateau fractures, and 19% had associated ipsilateral femoral fractures. Peroneal nerve injury occurred in 25% of knees, arterial injury in 21%, and compartment syndrome in 16%. An intra-abdominal injury was present in 13% of patients, a severe closed head injury in 10%, and a symptomatic pulmonary embolism in 5%.

CONCLUSIONS

Nearly half the multiligamentous knee injuries involved the anterior cruciate ligament, posterior cruciate ligament, and posterolateral corner; one-fourth had associated ipsilateral tibial plateau fractures. The incidence of peroneal nerve injury (25%) was higher than previously reported (20%), whereas the incidence of arterial injury (21%) was comparable to previous reports (19%). Posterolateral corner injuries were more prevalent than previously reported and were highly associated with peroneal nerve injury. We found a substantial incidence of associated morbidities of the whole body. Multiligamentous knee injuries are a marker of concomitant trauma and should be closely evaluated at presentation and during the hospital course to allow for early intervention for life- or limb-threatening comorbidities.

Impact of obesity on orthopaedics

The prevalence of obesity among children and adults is increasing worldwide. There are substantial health risks and financial costs associated with the obesity epidemic that impact the practice of orthopaedic surgery. Patients with increased body mass index are more prone to sustaining distal extremity injuries than are those with a normal body mass index. Obese individuals are more likely than nonobese individuals to seek treatment for osteoarthritis of the knee.

Effects of obesity on pediatric fracture care and management

Obese children have a theoretically increased risk of sustaining an extremity fracture because of potential variations in their bone mineral density, serum leptin levels, and altered balance and gait. Trauma databases suggest an increased rate of extremity fractures in obese children and adolescents involved in polytrauma compared with nonobese children and adolescents. Anesthetic and other perioperative concerns for obese pediatric trauma patients undergoing surgery include higher baseline blood pressures, increased rates of asthma, and obstructive sleep apnea. A child's weight must be considered when choosing the type of implant for fixation of pediatric femoral fractures. Fracture prevention strategies in obese pediatric patients consist of ensuring properly sized safety gear for both motor vehicles and sporting activities and implementing structured weight-loss programs.

Risk factors for peroneal nerve injury and recovery in knee dislocation

BACKGROUND

Acute knee dislocation is rare but has a high rate of associated neurovascular injuries and potentially limb-threatening complications. These include the substantial morbidity associated with peroneal nerve injury: neuropathic pain, decreased mobility, and considerably reduced function, which not only impairs patient function but complicates treatment.

QUESTIONS/PURPOSES

We therefore identified and quantified the risks associated with specific factors for peroneal nerve injury and recovery in patients with knee dislocations.

PATIENTS AND METHODS

We retrospectively reviewed the charts of 26 patients, from among a cohort of all 91 knee dislocations, with a peroneal nerve palsy over a 5-year period. We then used univariable and multivariable statistics to identify risk factors predicting peroneal nerve injury and recovery.

RESULTS

Gender (odds ratio, 5.47), body mass index (odds ratio, 1.14), and fibular head fracture (odds ratio, 4.77) were associated with peroneal nerve injury. Only younger age was associated with peroneal nerve recovery.

CONCLUSIONS

Knowledge of the risk factors for peroneal nerve injury and the predictors of recovery in knee dislocation allows the treating surgeon to have a better understanding of the nature of the neurologic injury and modify management based on the anticipated return of nerve function.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Ultra-low-velocity knee dislocations

BACKGROUND

Reports of low-velocity knee dislocations have focused primarily on dislocations occurring during athletic competition. The authors identified a subset of patients with low-velocity knee dislocations that occurred during activities of daily living, such as stepping off a curb, stepping off a stair, or simply falling while walking (ultra-low-velocity dislocations).

HYPOTHESIS

Ultra-low-velocity knee dislocations are common in obese individuals and are associated with more complications than high-velocity knee dislocations.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A review of records identified 17 patients with knee dislocations that occurred during daily activities. All 17 were clinically obese, with an average body mass index (BMI) of 48 (BMI <25 is normal; ≥40 is severe obesity). Ligament injuries occurred in all 17 patients, neurologic injuries in 7, and popliteal artery injuries in 7. Thirteen (76.4%) of the 17 dislocations were anterior, 2 (11.8%) were posterior, and 2 (11.8%) were lateral. All dislocations were reduced closed and stabilized with splints, crossed pins, or external fixation; ligament reconstructions were done in 8 patients and popliteal artery repairs in 7. Above-knee amputations were required in 2 patients with vascular repairs because of tissue ischemia; 1 patient died from cardiac arrest 7 days after injury; and 3 were lost to follow-up. Of the 11 remaining patients, 6 had ligament reconstructions and 5 did not.

RESULTS

Four standardized knee scoring systems (International Knee Documentation Committee [IKDC], Hospital for Special Surgery [HSS], Lysholm, Tegner) were used to evaluate outcome at an average follow-up of 28.5 months. Although scores were low in all patients, those with ligamentous reconstruction had better outcomes ("fair": 74 ± 22) than those without reconstruction ("poor": 21 ± 8.5), with a statistically significant (P = .013) difference in HSS scores. Lysholm scores also were higher in those with reconstruction (average 67) than in those without (average 53), but the difference was not statistically significant (P = .45).

CONCLUSION

These results indicate that (1) neurovascular injuries are frequent with these ultra-low-velocity dislocations in severely obese patients, (2) the likelihood of combined neurovascular injury tends to increase as BMI increases, and (3) surgical ligament reconstruction with emphasis on posterolateral corner repair appears to improve outcomes.

Management of upper extremity injuries in obese patients

Upper extremity injuries are more prevalent in obese people than in nonobese people after low-energy falls. Because splinting and casting are inefficient methods of stabilization in the setting of obesity, internal fixation provides stability for mobilization and realignment. Morbid obesity adversely affects positioning, surgical exposures, and complications associated with operative fixation. Avoiding short cuts and complications, morbidly obese patients should be able to return to normal functioning.

Diagnosis and management of knee dislocations

An acute knee dislocation is an uncommon injury, with a high rate of associated vascular and neurologic injuries as well as potentially limb-threatening complications. High-energy trauma is the most common cause of an acute knee dislocation, although lower-energy injuries, such as those sustained during athletic competition, are increasing in incidence. Injuries to the popliteal artery and common peroneal nerve are relatively common, requiring a high index of suspicion and complete neurovascular examination in a timely fashion. All cases of suspected knee dislocation should have an ankle-brachial index performed, reserving arteriography for those with an abnormal finding. Initial management consists of closed reduction, if possible, and application of a hinged brace or external fixator. Definitive management remains an area of controversy, although anatomic surgical repair or reconstruction is favored by most surgeons to help optimize knee function. Most patients treated for a knee dislocation can expect to return to their daily activities, but with less predictable returns to sporting activities.

Knee and leg injuries

The knee plays a significant role in ambulation and the activities of daily living. During the course of these activities and its role in weight bearing, the knee is susceptible to a variety of different forces and the emergency physician should be familiar with the diagnosis and treatment of the injuries that result. In addition to following basic trauma protocols, thorough neurovascular and musculoskeletal examinations should be performed and supplemented with appropriate imaging. Emergency physicians should also consider recent developments in knee anatomy and function when evaluating the patient with an acutely injured knee.

Bariatric trauma

The traumatised bariatric patient presents unique challenges and difficulties. Approximately 25% of adults in the United Kingdom are obese and 2% are morbidly obese. With an increasing incidence of obesity, understanding the specific challenges of managing the traumatised obese patient is vital for trauma practitioners.

Common injuries in athletes with obesity and diabetes

Musculoskeletal injuries and diseases are common in persons with obesity and diabetes mellitus. High body mass index is associated with an increased risk for musculoskeletal injuries, diseases, and disability. There is a significant positive correlation between the level of obesity and musculoskeletal injuries, and disability and health-related costs. The prevalence of obesity and diabetes is inversely proportional to health-related quality of life.