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Background: Knee dislocations (KD) are limb threatening injuries known to cause significant dysfunction and disability. This review aims to summarize KD knowledge and uncover areas where more research is needed., Methods: The published literature was queried according to PRISMA guidelines. Studies eligible for inclusion were clinical studies of knee dislocations. Studies published before 1990, or that focused on patellofemoral dislocation were excluded., Results: A total of 132 studies involving 43,869 knee dislocations were analyzed. The majority of patients were young adult males, with high-velocity trauma, particularly motor vehicle accidents, being the most common cause. Substance use and alcohol involvement were commonly reported. The predominant KD types were KD III (54.8 %) and KD IV (20.5 %). Meniscal tears were observed in over 50 % of cases, while cartilage injuries were present in 26.7 %. Neurovascular complications were significant, with popliteal artery injuries in 7.8 % and peroneal nerve injuries in 15.3 % of patients. Acute ligament repairs (64.2 %) were more common than delayed repairs (35.8 %), although the average time to repair was 56.1 days. Complications included amputations (2.3 %), fatalities (1.9 %), compartment syndrome (2.7 %), deep infection (5.3 %), and heterotopic ossification (21.6 %). Despite these severe injuries, a substantial loss to follow-up (19 %) and underreporting of functional outcomes were noted, limiting the comprehensive assessment of long-term recovery. A notable percentage of patients did not return to work or sports, with many requiring a change in profession due to their injuries, but these outcomes were only reported in 10 or fewer studies., Conclusion: This study highlights the significant gaps in understanding the treatment strategies, financial burden, and long-term outcomes of knee dislocations. The incomplete data, particularly the high loss to follow-up rates and underreported functional outcomes, hinders the ability to make comprehensive assessments. Available results should thusly be interpreted with an understanding of the gaps in data, however return to sport and prior employment is often not achieved. Additionally, the potential influence of socioeconomic factors and substance abuse on treatment decisions and outcomes remains inadequately explored. Future research should focus on these areas to improve the management and prognosis of patients with knee dislocations, ensuring more accurate and thorough evaluations of long-term recovery and quality of life., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Background: Traumatic proximal tibiofibular fracture and dislocation (PTFD) have been rarely studied and are easily missed in clinical practice. PTFD is considered a marker of severely traumatized knees. The purpose of this study was to retrospectively analyze the incidence and impact of PTFD in traumatized knees with vascular injury., Methods: Patients with knee trauma and vascular injury were included from January 2022 to October 2023. X-rays and CT scans of included patients were retrospectively analyzed to determine the presence of PTFD. Patients were further divided into PTFD group and non-PTFD group for further comparative analysis., Results: A total of 27 patients (28 limbs) were included. Incidence of PTFD was 39.3% (11/28) in traumatic knee with vascular injury, including 8 anterolateral dislocations and 3 posteromedial dislocations. PTFD group had significantly more limbs with open injuries compared with non-PTFD group (10/11 VS 7/17, p<0.05). Amputation rate of PTFD group was as high as 40% (4/10), compared to 23.5% (4/17) in non-PTFD group. However, the difference between two groups was not statistically significant (p>0.05)., Conclusions: PTFD was easily overlooked or missed. In traumatized knees with vascular injury, incidence of PTFD was high. The presence of PTFD might indicate severe knee trauma and the possibility of open injury. Although there was no significant difference compared with non-PTFD group, PTFD group had a relatively high amputation rate of 40%., (© 2024. The Author(s).)

Purpose: Knee dislocation is a rare but severe injury of the lower extremities. The aim of this study was to report on the epidemiology, diagnostics and treatment of such injuries and to identify negative predictors of clinical outcomes., Methods: This retrospective analysis included all knee dislocations treated at a Level I Trauma Centre in Germany between 2009 and 2021. Medical records were categorised, collected and analysed in a standardised manner. A follow-up visit 1 year after the injury focused on limitations in knee mobility., Results: A total of 120 knee dislocations were included in the study. 29.3% of patients presented to the emergency department with a dislocated joint, and 17.5% (n = 21) had a neurovascular lesion. At follow-up 12 months after the injury, 65.8% of the patients reported limitations in the range of motion, and 11.7% (n = 14) reported severe limitations in daily activities. Site infections due to surgery occurred in 3.3% of patients. Increased body weight (r = 0.294; p < 0.001 and r = 0.259; p = 0.004), an increased body mass index above 25 kg/m 2 (body mass index, r = 0.296; p < 0.001 and r = 0.264; p = 0.004) and deficits in peripheral perfusion as well as sensory and motor function (r = 0.231; p = 0.040 and r = -0.192; p = 0.036) were found to be negative predictive factors for clinical outcome. For posttraumatic neurovascular injury, lack of peripheral perfusion, insufficient sensory and motor function (r = -0.683; p < 0.0001), as well as a higher Schenck grade (r = 0.320; p = 0.037), were identified as independent risk factors. The status of dislocation at the site of the accident and on arrival at the emergency department had no impact on the outcome or neurovascular injury., Conclusion: Knee dislocation is a rare injury with a high rate of severe complications such as neurovascular lesions. In particular, the initial status of neurovascular structures and injury classification showed a relevant negative correlation with the posttraumatic status of nerves and vessels. In particular, patients with these characteristics need close monitoring to prevent negative long-term consequences., Level of Evidence: Level III., (© 2024 The Authors. Knee Surgery, Sports Traumatology, Arthroscopy published by John Wiley & Sons Ltd on behalf of European Society of Sports Traumatology, Knee Surgery and Arthroscopy.)

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., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Chen, Li, Zhou, Ye and Yang.)

Background: Previous research has found that the incidence of neurovascular injury is greatest among multiligamentous knee injuries (MLKIs) with documented knee dislocation (KD). However, it is unknown whether there is a comparative difference in functional recovery based on evidence of a true dislocation., Purpose: To determine whether the knee dislocation-3 (KD3) injury pattern of MLKI with documented tibiofemoral dislocation represents a more severe injury than KD3 MLKI without documented dislocation, as manifested by poorer clinical outcomes at long-term follow-up., Study Design: Cohort study; Level of evidence, 3., Methods: A multicenter retrospective cohort study was performed of patients who underwent surgical treatment for KD3 MLKI between May 2012 and February 2021. Outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner activity scale, and visual analog scale (VAS) for pain. Documented dislocation was defined as a radiographically confirmed tibiofemoral disarticulation, the equivalent radiology report from outside transfer, or emergency department documentation of a knee reduction maneuver. Subgroup analysis was performed comparing lateral (KD3-L) versus medial (KD3-M) injuries. Multivariable linear regression was conducted to determine whether documented dislocation was predictive of outcomes., Results: A total of 42 patients (25 male, 17 female) were assessed at a mean 6.5-year follow-up (range, 2.1-10.7 years). Twenty patients (47.6%) were found to have a documented KD; they reported significantly lower IKDC (49.9 vs 63.0; P = .043), Lysholm (59.8 vs 74.5; P = .023), and Tegner activity level (2.9 vs 4.7; P = .027) scores than the patients without documented dislocation. VAS pain was not significantly different between groups (36.4 vs 33.5; P = .269). The incidence of neurovascular injury was greater among those with documented dislocation (45.0% vs 13.6%; P = .040). Subgroup analysis found that patients with KD3-L injuries experienced a greater deficit in Tegner activity level than patients with KD3-M injuries (Δ: -3.4 vs -1.2; P = .006) and had an increased incidence of neurovascular injury (41.7% vs 11.1%; P = .042). Documented dislocation status was predictive of poorer IKDC (β = -2.15; P = .038) and Lysholm (β = -2.85; P = .007) scores., Conclusion: Patients undergoing surgical management of KD3 injuries with true, documented KD had significantly worse clinical and functional outcomes than those with nondislocated joints at a mean 6.5-year follow-up. The current MLKI classification based solely on ligament involvement may be obscuring outcome research by not accounting for true dislocation., Competing Interests: One or more of the authors has declared the following potential conflict of interest or source of funding: L.M.J. has received research support from Arthrex, Mitek, and Smith & Nephew; and support for education from Suvon Surgical, Gotham Surgical, Arthrex, and Flexion Therapeutics; L.M.J. also holds stocks or stock options in Lazurite. M.J.M. has received consulting fees from Smith & Nephew. M.J.A. has received consulting fees from BodyCad, JRF Ortho, Mitek, and DePuy Synthes; research support from Orcosa; and support for education from Gotham Surgical Solutions and Suvon Surgical. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.

Purpose: Knee dislocations (KDs) are rare in orthopaedic trauma but can have devastating effects. Failing to diagnose a concomitant vascular injury can lead to amputation. Different methods are used for the diagnosis of a vascular injury and the best approach is under debate. This study aims to examine the risk factor(s) of vascular injury in patients with KDs, examine variables that differ between obese patients and non-obese patients with KDs, and analyse the modalities used to identify vascular injuries in the KD population., Methods: The electronic patient medical record system at a major trauma centre was retrospectively reviewed to identify knee dislocations from 2015 to 2022. These were stratified based on age, gender, BMI, mechanism of injury, vascular injury, non-vascular complications, and laterality. Co-variates were inputted into a univariable regression analysis, followed by a multivariable regression analysis to identify risk factors of vascular injury in patients with knee dislocations. Co-variates were also compared between obese and non-obese patients using two-tailed t-tests for continuous variables and chi-squared test for categorical variables., Results: Forty patients were identified with a KD, with twenty-eight males and twelve females. The average age was 42.9 years, seventeen patients had a BMI of thirty or over, and eleven patients (27.5%) had a vascular injury. Open injuries (OR: 2.21; 95% CI: 1.19-11.30; p = 0.038) and obesity (OR: 2.66; 95% CI: 1.45-18.69; p = 0.027) are risk factors for vascular injury in patients with knee dislocation. Compared to non-obese patients, obese patients had a higher rate of open injury (p = 0.028), vascular injury (p = 0.017), low-energy injuries (p = 0.014), non-vascular complications (p = 0.017), and amputation (p = 0.036)., Conclusion: Open injuries and obesity are risk factors for vascular injury in patients with KD. Compared to non-obese patients, obese patients have low-energy injuries and an increased rate of non-vascular complications, meaning that clinicians could err on the side of caution when investigating vascular injury., Level of Evidence: IV., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Author(s). Published by Elsevier B.V. All rights reserved.)

Introduction: Current classifications of complete knee dislocations do not capture the extent of the complex concomitant ligamentous and bony injuries, which may have an impact on future outcomes. The purpose of this retrospective study was to evaluate the epidemiology of complete knee dislocations as well as to present an updated classification system based on the author's experience at a Level-I trauma center., Materials and Methods: Only patients with complete loss of contact of the articulating bones and ≥ 18 years of age who admitted in our level-I trauma center between 2002 and 2019 were included. Patients were identified using a retrospective systematical query in the Hospital Information System (HIS) using the International Statistical Classification of Diseases and Related Health Problems Version10 (ICD-10) codes of the German Diagnosis Related Groups (G-DRG)., Results: Final data included 80 patients, with the majority of patients being male (n = 64; 80.0%). Mean age was 34.9 years (range: 18-70 years). External protective fixation was applied in 32 patients (40.0%). Reconstruction of the posterior cruciate ligament and the anterior cruciate ligament were performed in 56.3% (n = 45) and 55.0% (n = 44) of cases, respectively. The lateral collateral ligament complex was surgically addressed in 47.5% (n = 38), while the medial collateral ligament complex was reconstructed in 40% (n = 32). Surgery of the lateral meniscus and the medial meniscus was needed in 31.1% (n = 25) and 30.0% (n = 24). Neurovascular surgery occurred in 13.8% (n = 11). From the characteristic injury-patterns the authors of this study present a new classification system that ranks the injuries from Grade-A to Grade-D according to their severity., Conclusion: This retrospective study demonstrates that the historically used classification systems for dislocations of the knee are insufficient for these severe injuries. Concomitant ligamentous, neurovascular, bony, and meniscal injuries were frequent, and required several staged procedures. Consequently, an updated classification system is proposed., (© 2021. The Author(s).)

Introduction: Traumatic proximal tibiofibular joint dislocations occur infrequently and are typically the result of high-energy trauma. These injuries can be a marker of limb injury severity because patients often sustain vascular injury and are at high risk of amputation. The purpose of this study was to present a systematic review of traumatic proximal tibiofibular joint dislocations and compare rates of associated injuries with a retrospective series of patients at a level 1 trauma center. The secondary objective was to report rates and clinical predictors of limb amputation., Methods: A systematic review was conducted, identifying three studies meeting eligibility criteria. A retrospective chart review was conducted identifying 17 skeletally mature patients with proximal tibiofibular dislocation treated from January 2010 to February 2021. A chart review extracted patient demographics, fracture patterns, open fracture, preoprative and postoperative peroneal nerve injury, vascular injury, and amputation. Binary logistic regression analysis was used to identify clinical predictors of outcomes., Results: Sixteen of 17 proximal tibiofibular injuries (94.1%) were associated with fracture, most commonly tibial shaft (n = 11, 68.75%). Twelve of 17 fractures (76.5%) were open. Five vascular injuries (29.4%) occurred requiring surgical intervention. Seven (41.2%) preoperative peroneal nerve deficits were noted; six had persistent deficits postoperatively or underwent amputation (average follow-up 31.3 ± 32.6 months). Two patients in the sample without preoperative peroneal nerve deficits were noted to exhibit them after fixation. Eight patients (47%) underwent an amputation, 7 (87.5%) of whom had an open fracture and 4 (50%) of whom had documented vascular injury., Discussion: Traumatic proximal tibiofibular fractures indicate severe injury to the lower extremity with high risk for nerve injury and possible amputation. Patients who present with vascular injury and open fracture in association with proximal tibiofibular joint disruption may be at elevated risk of amputation., (Copyright © 2022 The Authors. Published by Wolters Kluwer Health, Inc. on behalf of the American Academy of Orthopaedic Surgeons.)

Knee joint dislocation is a relatively uncommon injury but its management is important because of the associated high risk of vascular, neurological and multi-ligamentous knee injuries. Clinicians must be aware that not all knee dislocations are diagnosed on plain X-rays; a high index of suspicion is required based on clinical evaluation. Multidisciplinary specialist care is required in all cases to achieve best outcomes. Early one-stage or multiple staged ligament repair and reconstruction offer better outcomes, but most patients have some long-term functional limitation. This article provides insights into the epidemiology and management of this injury and its devastating effects.

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.

Background: Bearing dislocation is a common postoperative complication of mobile-bearing unicompartmental knee arthroplasty, and East Asian patients tend to be at higher risk. However, whether this high dislocation rate is common in all East Asian populations remains unclear. This meta-analysis was performed to explore this issue and describe various features of dislocation in East Asians, including the onset time, dislocation direction, and re-dislocation rate., Methods: The literature was searched in PubMed, Embase, Ovid, and Cochrane Library up to May 2020. Studies were scrutinized by two independent authors, and the bearing dislocation rate, onset time, direction, and re-dislocation rate were specifically analyzed. RevMan 5.3 was used for the statistical analysis., Results: Seven case series from Korea, China, and Japan were included. The pooled analysis showed that the total dislocation rate was 2.37%, while the subgroup analysis showed that the dislocation rate in Korea and other countries was 4.50% and 0.74%, respectively (P < 0.01). Another subgroup analysis of the onset time showed a significant difference before and after the first 5 years postoperatively (P < 0.01). Anterior and posterior dislocations were more frequent than medial and lateral dislocations (P < 0.01). The average re-dislocation rate was 32.45%, which was approximately seven times higher than the primary dislocation rate (P < 0.01)., Conclusion: Our meta-analysis demonstrated that Korea had a higher bearing dislocation rate among East Asian countries, especially in the first 5 years after primary UKA. Anterior and posterior dislocations were common. The most important finding is that the re-dislocation rate can be much higher than the initial dislocation rate.

PURPOSE OF THE STUDY Acute knee dislocation is a less common injury of the knee joint. It is, however, a serious injury with a high rate of nerve and vascular damage and it is considered a limb threatening injury with long-term functional disability, which can ultimately lead to amputation. Knee dislocations constitute less than 0.5% of all joint dislocations. Most of these injuries occur in highenergy traumas and careful diagnosis can identify the patient at risk of this injury. MATERIAL AND METHODS The total number of patients with knee dislocation was 37. The incidence of knee dislocation was 2.5 patients per year. The mean age of patients was 49 years. After the evaluation of blood supply to the limb and before the examination of the ligament injury, routine X-ray views of the affected joint were performed. It was necessary to confirm good blood supply of the limb, in which knee dislocation had been suspected. In patients with reduced knee joint and asymmetric pulses in the lower limb, CT angiography was indicated. The absence of peripheral pulses and the presence of serious clinical signs of peripheral blood supply disruption in case of the reduced knee or irreducible knee dislocation necessitated immediate revision by a vascular surgeon performed in the operating room. RESULTS Dislocation of the knee without TKA (a total of 34 cases) was caused by a high-energy trauma in 19 cases (56%) and in 7 cases (21%) it was a part of polytrauma. The most common was a motorcycle accident, namely in 7 cases (21%). In 12 cases (35%), it was a low-energy trauma, a fall or a slip while walking. In three cases (9%), the patients suffered an open knee dislocation. In 18 patients (47%), no knee surgery was performed. The knee ligament injury was treated non-operatively through knee brace fixation. An open revision with sutures of injured ligament structures and knee capsule was performed in 16 patients (42%). In two cases, above-the-knee amputation was done. External fixation was performed in two polytrauma patients. Three cases of infectious complications were reported. Nerve lesions were observed in 9 cases (25%). Vascular lesions were recorded in 9 cases (25%). Deep vein thrombosis was observed in three cases in our study group. The Lysholm knee questionnaire was used to assess subjective difficulties. DISCUSSION In agreement with the literature, these injuries occur most frequently when riding on motorcycle. The patients, in whom a vascular lesion was identified and revascularisation performed within 8 hours, showed a significantly lower incidence of amputations (11%) compared to those who underwent surgery after 8 hours (86%). Majority of vascular surgeons consider 6 hours to be the time limit for the performance of vascular reconstruction since a surgery performed after 6 hours is accompanied by a higher complication rate. Currently, the aim of the final treatment is to perform anatomic suture or reconstruction of knee ligaments and meniscus to achieve a stable, pain-free, functional knee and to prevent any complications. CONCLUSIONS Knee joint dislocation ranks among less common injuries that can be accompanied by a vascular injury in 20% on average and a nerve lesion in 10-40% (around 25% on average). A negative X-ray in spontaneous reduction of knee dislocation can be misleading for proper diagnosis. It is crucial to rule out a vascular injury that might be a limb threatening. In case of a vascular lesion, an early reconstruction of vascular supply is necessary within 6 hours after the injury. The revascularisation performed later is accompanied by a high risk of complications and can ultimately lead to above-the-knee amputation. It is most appropriate to refer such serious injuries to specialised trauma centres that avail of necessary equipment and experience with treating the patients who sustained such complicated orthopaedic injuries. As to the ligament reconstruction, most surgeons prefer to postpone the procedure in majority of cases by 10-14 days. Key words: knee dislocation, vascular injury, neurologic injury, ligament reconstruction, irreducible dislocation.

Purpose: Congenital dislocation of the knee and hip is a rare congenital disorder. The specific aim of the study was to evaluate the clinical and radiological outcomes of the children with congenital dislocation of the knee and hip who presented after six months of age., Methods: All the consecutive children with congenital dislocation of the knee and hip joints were retrospectively reviewed. We included cases that were treated after six months of age and followed up for a minimum of two years. Twenty-four children with congenital dislocation of the knee and hip (thirteen with ligamentous laxity, eleven children with stiff joints) were included. The knee was dislocated in 45 limbs; the hip was dislocated in 40 instances. The knee joint dislocation was treated with quadricepsplasty in all twenty-four children (45 knees). The hip dislocation (n = 32) was addressed with either closed reduction (n = 8) or open reduction of the hip (n = 24). Eight hip dislocations were not addressed. The outcome of the hip and knee was evaluated., Results: The clinical and radiological outcomes were better in children with ligamentous laxity than without laxity. Twenty-two children were community walkers. An orthosis was needed in eight children. The frequency of spontaneous reduction of unreduced dislocation of the hip was noted in three children (5/8 hips)., Conclusion: Outcome in combined dislocation of knee and hip is good in most cases with surgical interventions. The outcome is better in children with ligamentous laxity. Spontaneous reduction of the dislocated hips might be achieved after gaining knee flexion following knee surgery for congenital the knee in a few cases.

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.

Objective: To describe the associations between mechanism of injury energy level and neurovascular injury (NVI) following knee dislocation (KD) using a large representative sample of trauma patients and to examine risk factors within these groups., Design: Retrospective cohort study., Setting: Trauma centers participating in the American College of Surgeons National Trauma Data Bank., Participants: Adult patients with KD without lower extremity fracture., Intervention: Patients were grouped as ultra-low, low, or high-energy based on injury mechanism. Univariate/multivariate analyses assessed associations of energy level with NVI and of patient characteristics with NVI within energy-level groups., Main Outcome Measurements: Rate of nerve and blood vessel injury., Results: One hundred twenty-four patients with KD were identified; 181 sustained ultra-low-energy mechanisms, 275 low-energy, and 868 high-energy. Nerve injury occurred in 6% of ultra-low-energy injuries, 7% in low-energy, and 3% in high-energy (P = 0.03). Vessel injury occurred in 21% of ultra-low-energy injuries, 17% in low-energy, and 13% in high-energy (P = 0.01). On multivariate analyses, obesity was associated with nerve injury in the ultra-low-energy group (OR 4.9; 95% CI 1.0-24.0) but not with other energy levels. Obesity was also associated with vessel injury in the ultra-low-energy group (OR 4.0; 95% CI 1.6-9.7). Smoking, hypertension, and diabetes were not associated with NVI., Conclusions: NVI following KD is more common after lower energy-level mechanisms. Obesity is associated with NVI in lower energy-level mechanisms. Physicians should be vigilant in screening for NVI in the setting of KD even with seemingly benign mechanisms of injury, especially in patients with obesity., Level of Evidence: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Background and Purpose: Traumatic dislocation of the knee (TKD) is a rare injury, accounting for approximately 0.02% of orthopaedic injuries. They are a challenging entity for orthopaedic surgeons to manage, and can have devastating consequences. The aim of this study was to describe the epidemiology of traumatic knee dislocations (TKD'S) and contrast the incidence of neurovascular injury between isolated and multi-trauma dislocations as well as key patient reported outcomes achieved between these groups., Material and Methods: Patients who had a traumatic disruption of the tibiofemoral articulation between March 1 2007 and February 31, 2015 were identified from the Victorian Orthopaedic Trauma Outcomes Registry (VOTOR). Data was cross-checked with medical records and radiological reports to confirm true multi-ligamentous dislocation. VOTOR collects information pertaining to orthopaedic injuries, treatment, complications and outcomes from four adult hospitals in Victoria, Australia, including the major trauma centers. Patient-reported outcomes are collected by VOTOR at 12 months post-injury including the EQ-5D-3L (EQ-5D) and Glasgow Extended Outcome Scores (GOS-E) and return to work status. Patient reported functional and quality of life outcomes at 12 months after injury were analysed., Results: A cohort of 88 patients were identified that fit the inclusion criteria for the study, and at 12 months post-injury there was data available for 80 patients (90.9%). There were 38 (42.9%) patients who experienced an isolated traumatic knee dislocation and 52 (57.1%) who experienced a traumatic knee dislocation in association with another injury. Of the 88 patients identified as eligible for the study, two had bilateral knee dislocations, hence there were 90 multi-ligamentous knee injuries. Those who were injured at a higher velocity were more likely to have additional injuries. Dislocations that occurred at a lower velocity were shown to have better overall outcomes, as did dislocations that occurred in isolation., Conclusions: Traumatic knee dislocations that occur in isolation typically result in better outcomes than those that occur with associated injuries. TKD's are a rare but severe injury that requires further research in order for functional outcomes to be optimized., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Introduction: Knee dislocation is a rare but potentially devastating injury. Quoted rates of associated vascular compromise vary dramatically between 3.3% and 64%, and the best approach to investigate and diagnose such an injury remains controversial. We aim to evaluate our own 4-year experience of knee dislocation and vascular injury as a UK Major Trauma Centre and vascular hub., Methods: Knee dislocation was defined as disruption of at least two major stabilising ligaments of the knee and gross instability requiring an operation. Patients were identified from the Department of Trauma and Orthopaedics patient database across a 4 year period from 2010 to 2014. Electronic patient records, imaging and hard notes were retrieved and reviewed retrospectively and relevant information recorded., Results: Twenty-five cases of knee dislocation were identified. Male to female ratio was 11.5:1 with a mean age of 33 years (range 17-71). One patient had a vascular injury which ultimately required a femoro-popliteal bypass graft. Twenty-four patients had documented examination findings pertaining to the vascular status of the limb. Seventeen patients had specific reference to the presence or absence of pedal pulses. The remaining seven cases were documented as either "warm well perfused" or "neurovascularly in-tact". Nine patients were discharged directly from the emergency department with outpatient follow up. All admitted cases had documented vascular examination findings the following day. Two patients had additional adjunctive non-invasive investigations. No patients were examined with duplex ultrasound, although two patients had pulses confirmed with hand-held doppler ultrasound. Three patients had an angiogram. Four cases have a documented discussion with or review from a vascular surgeon., Discussion and Conclusions: Our rates of vascular injury are in line with the most recent and largest study to date. Non-invasive investigation and selective angiography has been safe in identifying significant vascular compromise, however, there is inconsistency in management pathways, and too much reassurance attributed to the presence of pedal pulses on initial examination. Safety and consistency could be improved with the introduction of a formalised evidence-based protocol for the initial evaluation of knee dislocation and vascular injury., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Objective: The purpose of this analysis is to report on the epidemiology and clinical implications of traumatic proximal tibiofibular dislocation (PTFD)., Design: Retrospective chart and radiographic review., Setting: Level 1 regional trauma center., Patients: Skeletally mature patients with a traumatic PTFD between July 1, 2006, and December 31, 2013., Intervention: Open reduction internal fixation of the proximal tibiofibular joint., Main Outcome Measurements: Patient demographics and associated musculoskeletal and neurovascular injuries were recorded as data points., Results: There were a total of 30 PTFDs in 30 patients during the course of the defined study period. The incidence of PTFD was 1.5% (15 of 1013) of operative tibial shaft fractures and 1.9% (15 of 803) of operative tibial plateau fractures (P = 0.5810). Fifty percent (15 of 30) of PTFD were associated with a tibial shaft fracture, and 50% (15 of 30) with tibial plateau fractures. PTFD was associated with an open fracture in 63% (19 of 30) of cases. Two patients (6.7%) presented with a vascular injury who underwent a successful repair without vascular sequelae. Two different patients (6.7%) ultimately underwent an amputation (one above the knee and one below the knee) for a nonreconstructable extremity. In the remaining 28 patients without amputation, the incidence of compartment syndrome was 29% (8 of 28) and the incidence of peroneal nerve palsy was 36% (10 of 28). Only 30% (3 of 10) of the peroneal nerve palsies recovered clinically within the follow-up period, which averaged 11 months (range: 6 months to 4 years)., Conclusions: Traumatic proximal tibiofibular joint dislocations can be found in approximately 1%-2% of both tibial plateau and shaft fractures. PTFD is associated with a high rate of compartment syndrome (29%), open fracture (63%), and peroneal nerve palsy (36%). The majority (70%) of peroneal nerve palsies do not recover. Proximal tibiofibular joint dislocation is a marker for a severely traumatized limb., Level of Evidence: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

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.

Background: Vascular injury secondary to an acute knee dislocation is a known complication. However, there exist wide discrepancies in the reported rate of vascular injury in this setting., Questions/purposes: Using a large private insurance database, we determined the frequency of vascular injury in knee dislocations across year of diagnosis, age, sex, and US geographic region and the proportion of these injuries requiring surgical repair., Methods: The PearlDiver database, which contains records from 11 million orthopaedic patients, was searched using ICD-9 diagnostic codes for all knee dislocation events from 2004 to 2009. Within this subset, we identified which knee dislocations had an associated vascular injury ICD-9 code. Patients were stratified by year of diagnosis, age, sex, and US geographic region, and Current Procedural Terminology codes were used to identify the subset of patients with vascular injury requiring surgical repair. Differences in frequency across demographic groups and over time were analyzed with Poisson regression analysis., Results: Among the 8050 limbs with knee dislocation identified over the study period, 267 had a concomitant vascular injury for an overall frequency of 3.3%. Males were found to have an increased risk of vascular injury compared to females (odds ratio = 2.59, p < 0.001). Additionally, patients aged 20 to 39 years had a higher risk of vascular injury when compared to those aged 0 to 19 years (odds ratio = 1.93, p = 0.001), 40 to 59 years (odds ratio = 1.57, p = 0.014), and 60 years or older (odds ratio = 2.81, p = 0.036). There were no differences in vascular injury frequency across US geographic regions or diagnosis year. Thirty-four of the 267 cases of vascular injury (13%) underwent surgical treatment., Conclusions: This is the largest study, to our knowledge, that analyzes the proportion of knee dislocations that result in vascular injury. Our data suggest that there is a lower frequency of vascular injury associated with knee dislocation and a lower proportion of vascular injuries undergoing surgical treatment than previously reported. These findings may support a more selective angiography protocol to screen for vascular injury, rather than performing this invasive diagnostic test on all knee dislocations, as has been done historically. Future large-scale and prospective studies should analyze factors that may predispose to vascular injuries after knee dislocation and determine which patients should be screened for vascular injury after knee dislocation., Level of Evidence: Level IV, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

Background: The multiple-ligament-injured knee represents a special challenge, being an uncommon injury that is both severe and complicated to treat. Many studies have evaluated patients treated for this injury, but most are limited in their scope. The evaluation of this injury and its treatment using an administrative database might provide a different perspective., Questions/purposes: Using a large administrative database, we determined (1) the number of multiligament knee reconstructions in New York State, (2) the rate of 90-day hospital readmission, and (3) the frequency of subsequent knee surgery. We examined the rates of these outcomes as a function of diagnosis, admission type, discharge status, comorbidity burden, and patient demographic factors., Methods: We used the New York Department of Health Statewide Planning and Research Cooperative System (SPARCS), a database with information on patient characteristics, diagnoses, and treatments, to identify patients who underwent a multiligament procedure in a nonfederal facility from 1997 to 2005 using ICD-9-CM and Current Procedural Terminology codes. SPARCS collects data from all nonfederal acute care facilities, with an estimated reporting completeness of almost 99% for the years in this study. We evaluated data on patient age, sex, admission type, discharge status, and comorbidity burden (using Elixhauser comorbidities) and developed a multivariable logistic regression model to assess the influence of confounding variables., Results: We identified 1032 patients in this database who underwent multiligament knee reconstruction in New York State from 1997 to 2005. The frequency of readmission within 90 days was 4.8% (n = 49). Readmission was more likely for patients who underwent inpatient multiligament reconstruction (odds ratio [OR] = 2.3; 95% CI: 1.2-4.4; p = 0.014), had a diagnosis of dislocation (OR = 2.2; 95% CI: 1.2-3.9; p = 0.011), or had various Elixhauser comorbidities, including chronic lung disease (OR = 6.4; 95% CI: 1.5-27.2; p = 0.013), fluid and electrolyte disorders (OR = 19.7; 95% CI: 2.5-155.7; p = 0.005), and anemia deficiency (OR = 5.6; 95% CI: 1.05-29.4; p = 0.044). Two hundred eighty-seven patients (28%) underwent subsequent knee surgery between their index procedure and 2006. Subsequent surgery was more likely for patients who underwent inpatient multiligament reconstruction (OR = 1.4; 95% CI: 1.1-1.9; p = 0.011) or were readmitted within 90 days of the index surgery (OR = 4.2; 95% CI: 2.3-7.6; p < 0.001)., Conclusions: Our findings have the potential to aid clinicians in identifying their patients with multiligament reconstruction at highest risk for 90-day readmission and subsequent knee surgery. Future research, particularly large prospective studies evaluating surgical approaches and timing, will be critical in advancing the treatment of multiligament knee injuries., Level of Evidence: Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Background: Vascular injury is a devastating complication of acute knee dislocation. However, there are wide discrepancies in the reported frequency of vascular injury after knee dislocations, as well as important differences among approaches for diagnosis of this potentially limb-threatening problem., Questions/purposes: We determined (1) the frequency of vascular and neurologic injury after knee dislocation and whether it varied by the type of knee dislocation, (2) the frequency with which surgical intervention was performed for vascular injury in this setting, and (3) the frequency with which each imaging modality was used to detect vascular injury., Methods: We searched the MEDLINE(®) literature database for studies in English that examined the clinical sequelae and diagnostic evaluation after knee dislocation. Vascular and nerve injury incidence after knee dislocation, surgical repair rate within vascular injury, and amputation rate after vascular injury were used to perform a meta-analysis. Other measures such as diagnostic modality used and the vessel injured after knee dislocation were also evaluated., Results: We identified 862 patients with knee dislocations, of whom 171 sustained vascular injury, yielding a weighted frequency of 18%. The frequency of nerve injuries after knee dislocation was 25% (75 of 272). We found that 80% (134 of 160) of vascular injuries underwent repair, and 12% (22 of 134) of vascular injuries resulted in amputation. The Schenck and Kennedy knee dislocation classifications with the highest vascular injury prevalence were observed in knees that involved the ACL, PCL, and medial collateral liagment (KDIIIL) (32%) and posterior dislocation (25%), respectively. Selective angiography was the most frequently used diagnostic modality (61%, 14 of 23), followed by nonselective angiography and duplex ultrasonography (22%, five of 23), ankle-brachial index (17%, four of 23), and MR angiography (9%, two of 23)., Conclusions: This review enhances our understanding of the frequency of vascular injury and repair, amputation, and nerve injuries after knee dislocation. It also illustrates the lack of consensus among practitioners regarding the diagnostic and treatment algorithm for vascular injury. After pooling existing data on this topic, no outcomes-driven conclusions could be drawn regarding the ideal diagnostic modality or indications for surgical repair. In light of these findings and the morbidity associated with a missed diagnosis, clinicians should err on the side of caution in ruling out arterial injury.

Purpose: Because the medial patellofemoral ligament (MPFL) is the primary restraint to lateral dislocation of the patella, we aimed, in this controlled study, to verify whether the MPFL with different measurements could be considered another predisposing factor for patellar dislocation., Methods: A group of 100 consecutive individuals without the criteria for patellar dislocation (trochlear dysplasia, patella alta and lateral patellar tilt) was recruited as a control group and underwent magnetic resonance imaging (MRI) study and another group of 50 patients with patellar instability. Femoral condyles, interepicondylar distance, length and thickness of the MPFL were measured., Results: In the control group, the MPFL was 38-60 mm long. Individuals with patellar instability who had no episode of patellar dislocation had a 4.11-mm longer ligament than controls (p = 0.032), while patients with instability with a previous history of dislocation had a 13.54-mm longer MPFL than controls (p < 0.001). Thickness of the MPFL at the patellar insertion was lower in individuals with patellar instability with a history of dislocation (p < 0.001). An instability coefficient (IC) less than 1.3 indicates that the MPFL is insufficient., Conclusions: Individuals with patellar instability and previous patellar dislocation present with longer MPFL when compared to controls, and an associated IC less than 1.3 can be considered a predisposing factor for patellar dislocation. Treatment of patellar instability is a challenge, and it is difficult to identify what is the predisposing factor. This study has verified the measurements of the MPFL for the first time and presents values of thickness and length that can be considered as indications for surgical reconstruction., Level of Evidence: III.

Background: Acute knee (tibiofemoral joint) dislocation is a serious knee injury, although population-based numbers and incidence rates of knee dislocation with or without concomitant vascular injury are unknown., Methods: The study covered the whole adult population of 4 million persons (aged ≥ 18 years) in Finland during the 11-year period from January 1, 1998, to December 31, 2011. Data on hospitalization caused by acute knee dislocations and concomitant vascular injuries requiring operative treatment were obtained from the nationwide National Hospital Discharge Registry., Results: During the 14-year study period, a total of 837 patients with knee dislocation diagnosis were hospitalized in Finland. The highest incidence rates in men were in persons aged 18 years to 29 years (incidence, 29 per 1 million person-years in 2011), and the incidence decreased by age, while in women, this incidence was rather similar in all age groups. The most common injury mechanism of knee dislocation was low-energy fall at the same level (46%). The median length of hospital stay was 2 days (range, 1-109 days). In 107 cases (13%), knee dislocation required immediate open (69 cases) or closed (38 cases) reduction in the operating room. Popliteal artery injury requiring acute surgical intervention was found in 13 patients (1.6%), and amputation at the level above the tibiofemoral joint was performed for one patient (0.1%)., Conclusion: This is the first study describing the population-based incidence of acute knee dislocation. Men aged 18 years to 29 years had the highest incidence rates. Half of the injuries were low-energy trauma. Popliteal artery injury requiring surgical intervention was a rare concomitant injury, but when present, the injury required immediate surgical repair to avoid dramatic consequences., Level of Evidence: Nationwide epidemiologic study, level I.

Objective: Most of the evidence regarding complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA) are based on patients with osteoarthritis (OA); less is known about outcomes in rheumatoid arthritis (RA). Using a validated algorithm for identifying patients with RA, we undertook this study to compare the rates of complications among THA and TKA recipients between those with RA and those without RA., Methods: In patients who underwent a first primary elective THA or TKA between 2002 and 2009, those with RA were identified using a validated algorithm: a hospitalization with a diagnosis code for RA or 3 physician billing claims with a diagnosis code for RA, with at least 1 claim by a specialist (rheumatologist, orthopedic surgeon, or internist) in a 2-year period. Recipients with diagnostic codes suggesting an inflammatory arthritis, but not meeting RA criteria, were classified as having inflammatory arthritis. All remaining patients were deemed to have OA. Cox proportional hazards models, censored on death, were used to determine the relationship between the type of arthritis and the occurrence of specific complications, adjusting for potential confounders (age, sex, comorbidity, and provider volume)., Results: We identified 43,997 eligible THA recipients (3% with RA) and 71,793 eligible TKA recipients (4% with RA). Total joint arthroplasty recipients with RA had higher age and sex-standardized rates of dislocation following THA (2.45%, compared with 1.21% for recipients with OA) and higher age and sex-standardized rates of infection following TKA (1.26%, compared with 0.84% for recipients with OA). Controlling for potential confounders, recipients with RA remained at increased risk of dislocation within 2 years of THA (adjusted hazard ratio [HR] 1.91, P = 0.001) and remained at increased risk of infection within 2 years of TKA (adjusted HR 1.47, P = 0.03) relative to recipients with OA., Conclusion: Patients with RA are at higher risk of dislocation following THA and are at higher risk of infection following TKA relative to those with OA. Further research is warranted to elucidate explanations for these findings, including the roles of medication profile, implant choice, postoperative antibiotic protocol, and method of rehabilitation following joint replacement., (Copyright © 2014 by the American College of Rheumatology.)

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.

Objective: Reports in the literature of low-energy (LE) knee dislocation (KD) in obese patients have been increasing. This study was undertaken to define the risk factors for KD by LE mechanisms and the outcomes of these patients compared with those with high-energy (HE) trauma., Methods: All patients with a complete KD presenting to the emergency department of a large urban level I trauma center were reviewed. Patient information collected included age, sex, weight, height, body mass index (BMI), injury mechanism, neurovascular and orthopedic injuries, and operations performed to treat vascular injuries. Risk factors for KD and concomitant injuries were compared between HE traumatic dislocations and LE dislocations in obese patients (BMI >30 kg/m(2)), including stratification for increasing levels of obesity., Results: Between January 1995 and April 2012, 53 patients with KD were identified. The mechanism of injury was HE in 28 (53%) and LE in 25 (47%). Of the LE KDs, 18 (72%) were related to obesity (BMI >30 kg/m(2)). Obese patients with LE trauma were more likely to have associated nerve injuries (50% vs 6%; P < .001), vascular injuries requiring intervention (33% vs 9%; P = .048), and vascular surgical repairs (28% vs 6%; P = .038) than patients with HE traumatic dislocations. These rates were highest in the patients with a BMI >40 kg/m(2). Although all LE KDs in the obese involved an isolated extremity, the hospital lengths of stay were comparable to those with HE KDs who frequently had multisystem trauma (8.7 vs 11.4 days). During a 17-year period, LE KDs in the obese represented an increasing proportion, from 17% in 1995 to 2000 up to 53% in 2007 to 2012, and the eventual majority of all KDs at our institution (P = .024)., Conclusions: LE KDs in obese patients are becoming increasingly prevalent. These patients are more likely to have nerve and vascular injuries and are more likely to undergo vascular repair than patients with HE trauma. The epidemic of obesity in the United States presents unique challenges in the identification and treatment of patients with LE KD and their associated injuries., (Copyright © 2013 Society for Vascular Surgery. Published by Mosby, Inc. All rights reserved.)

Background: Knee dislocation is an uncommon but serious injury that has traditionally been associated with high velocity injuries such as motor vehicle accidents. More recently, individual cases of obese individuals sustaining knee dislocation from a low velocity mechanism have been noted. Associated injuries of knee dislocation are common and include popliteal vessel damage requiring surgical repair and injuries to the peroneal nerve. Prompt diagnosis and reduction is essential to reduce the risk of these complications., Objectives: We aim to highlight the importance of prompt diagnosis and management of obese patients presenting with knee pain after a seemingly innocuous injury who may have a knee dislocation., Cases: We present a series of four cases of dislocation of the knee that have presented to our hospital over the course of 1 year. Each was sustained by a morbidly obese female of body mass index range 35-41, age range 33-52 years, experiencing a simple mechanical fall from standing. Magnetic resonance image scanning revealed multiple knee ligament rupture in all four cases. One case had peroneal nerve palsy., Conclusion: This is the first series of such injuries that we are aware of and highlights a potential future increase in incidence of these major injuries as body mass in society increases, placing more strain on health care resources. Practitioners in the Emergency Department need to be aware that serious injury can be present in morbidly obese patients that have sustained no more than a fall from standing height. Prompt investigation and management is essential., (Crown Copyright © 2013. Published by Elsevier Inc. All rights reserved.)

We report a prospective analysis of clinical outcome in patients treated with medial patellofemoral ligament (MPFL) reconstruction using an autologous semitendinosus graft. The technique includes superolateral portal arthroscopic assessment before and after graft placement to ensure correct graft tension and patellar tracking before fixation. Between October 2005 and October 2010, a total of 201 consecutive patients underwent 219 procedures. Follow-up is presented for 211 procedures in 193 patients with a mean age of 26 years (16 to 49), and mean follow-up of 16 months (6 to 42). Indications were atraumatic recurrent patellar dislocation in 141 patients, traumatic recurrent dislocation in 50, pain with subluxation in 14 and a single dislocation with persistent instability in six. There have been no recurrent dislocations/subluxations. There was a statistically significant improvement between available pre- and post-operative outcome scores for 193 patients (all p < 0.001). Female patients with a history of atraumatic recurrent dislocation and all patients with history of previous surgery had a significantly worse outcome (all p < 0.05). The indication for surgery, degree of dysplasia, associated patella alta, time from primary dislocation to surgery and evidence of associated cartilage damage at operation did not result in any significant difference in outcome. This series adds considerably to existing evidence that MPFL reconstruction is an effective surgical procedure for selected patients with patellofemoral instability.

Using general practitioner records and hospital notes and through direct telephone conversation with patients, we investigated the accuracy of nine patient-reported complications gathered from a self-completed questionnaire after elective joint replacement surgery of the hip and knee. A total of 402 post-discharge complications were reported after 8546 elective operations that were undertaken within a three-year period. These were reported by 136 men and 240 women with a mean age of 71.8 years (34 to 93). A total of 319 reported complications (79.4%; 95% confidence interval 75.4 to 83.3) were confirmed to be correct. High rates of correct reporting were demonstrated for infection (94.5%) and the need for further surgery (100%), whereas the rates of reporting deep-vein thrombosis (DVT), pulmonary embolism, myocardial infarction and stroke were lower (75% to 84.2%). Dislocation, peri-prosthetic fractures and nerve palsy had modest rates of correct reporting (36% to 57.1%). More patients who had knee surgery delivered incorrect reports of dislocation (p = 0.001) and DVT (p = 0.013). Despite these variations, it appears that post-operative complications may form part of a larger patient-reported outcome programme after elective joint replacement surgery.

We sought to summarize knee injuries (KI) in the U.S. Active Duty Army (ADA) in terms of absolute numbers, examine current rate trends, and identify ADA who were at increased risk for experiencing a KI. We used the Total Army Injury and Health Outcomes Database (TAIHOD) to compute unadjusted and adjusted rates of KI, categorized by the Barell Matrix, within the ADA for the years 2000-2005. During this period, 21 to 25 per 1,000 ADA suffered from KI. The highest yearly rates were observed for knee dislocation and sprains/strains (31 per 1,000 ADA). In ADA with a history of a KI (within 2 years), rates increased nearly tenfold. Elevated KI rates were also seen in ADA with prior upper or lower leg injuries, those > 30 years of age, and those with a category IV Armed Forces Qualification Test score (lowest admissible in Army). ADA KI rates remained fairly stable throughout the study period. Relative to other ADA Soldiers, those with prior knee, upper leg, or lower leg injuries are at increased risk for subsequent KI.

Knee injuries involving multiple ligaments, which are often associated with tibiofemoral joint dislocations, are complex injuries that are challenging to evaluate and treat. The clinician must have a thorough understanding of knee anatomy and be capable of a detailed physical examination to determine the extent and pattern of injury. Accurate interpretation of imaging studies is crucial but cannot replace the physical examination. The magnitude of deforming forces and amount of translation and rotation of the tibia in relation to the femur determine the risk for neurovascular injury. Most patients with multiligament knee injuries undergo surgical management; however, some patients may be best served by a nonoperative approach. Successful rehabilitation consists of achieving good range of motion and strength, as well as normal gait mechanics, while respecting the stages of healing.

The aim of this study was to evaluate complications related to prosthesis design in patients managed with cemented total knee arthroplasty using anterior-posterior glide mobile-bearing prosthesis. One hundred eighty-three total knee arthroplasties were performed using this prosthesis on 146 patients, with a minimum of 7 years of follow-up. There were late dislocations of the bearing in 2 knees, anterior soft tissue impingements in 6 knees at an earlier follow-up, excessive anteroposterior translation in 5 knees, and a fracture of the femoral component induced by osteolysis in 1 knee. Design modifications in the restraint mechanisms of the anterior-posterior glide mobile-bearing prosthesis may be required to minimize the development of complications with regard to sagittal instability and to improve the prosthesis' longevity., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Introduction: Knee dislocation and bicruciate lesions are rare. Assessments of results from retrospective series carry an insufficient level of evidence. A prospective multicenter study was therefore set up, under the auspices of the French Society of Orthopedic Surgery., Material and Methods: The inclusion period covered the whole of 2007. Clinical, imaging (dynamic X-ray and MRI) and vascular (angioscan and arteriography) assessment was performed systematically. In patients over the age of 60 years, ligament lesions were always managed non-surgically; in those under the age of 60 years, surgery was considered in the absence of associated vascular lesion or open dislocation and if there was frontal laxity exceeding 15 degrees or a posterior drawer test greater than 10mm. The posterior cruciate ligament (PCL) and peripheral ligament tears were repaired or reinforced under arthroscopy or by arthrotomy. The anterior cruciate ligament was never operated on. In all other cases, management was conservative., Results: Sixty-seven knees were included (55 male, 11 female; mean age: 37 years). Fifteen patients (25.4%) had bicruciate lesion, and 44 (74.6%) knee dislocation. Mean trauma-to-reduction interval was 3 hrs 50 min. Only one of the nine cases of popliteal artery lesion exhibited discernible distal pulse wave. Only three of these patients underwent vascular surgical repair. Twelve knees (five bicruciate lesions, seven dislocations) had isolated common peroneal nerve damage., Discussion: This prospective study detailed the epidemiology and treatment of the lesions encountered, with the option of PCL and peripheral ligament reconstruction. The results, however, still require long-term analysis.

The knee consists of three articulations: the patellofemoral, the tibiofemoral, and the proximal tibiofibular joint. Any of these joints can dislocate. Dislocations are uncommon, tend to spontaneously reduce, and can be difficult to detect on clinical examination. There are, however, telltale imaging features and the radiologist may be the first to suggest the correct diagnosis. A timely diagnosis is important as some forms are associated with limb-threatening complications. Lateral patellofemoral dislocation, in the acute setting, is typically an injury of young athletes and usually spontaneously reduces at the time of trauma. In transient lateral dislocation, contusions may be seen in the inferomedial pole of the patella and the anterior lateral aspect of the nonarticular portion of the femur. The important magnetic resonance imaging findings include this characteristic contusion pattern and injury to the medial patellar soft-tissue restraints. These are frequently associated with osteochondral fractures, which may be an indication for surgery. Recurrent patellofemoral dislocations tend to be associated with abnormalities of bony and/or soft-tissue restraints. The important imaging considerations are the length of patellar tendon, the depth of trochlear groove, and the position of patella in relation to the trochlear groove. Tibiofemoral dislocations are rare and are usually associated with high-impact trauma. These are multi-ligamentous injuries, which most often involve both cruciate ligaments with either medial and/or lateral ligament tears. There is an associated risk of popliteal artery and peroneal nerve injury, even if reduced, at the time of presentation. Dislocations of the tibiofibular joint are also rare and are classified based on location of fibular head. The tibiofibular joint is lax in flexion, and thus, most dislocations tend to occur in the flexed knee position. Anterolateral dislocation is the most common, while posteromedial dislocation is frequently associated with peroneal nerve injury. The purpose of this article is to review the epidemiology of knee dislocations, important imaging findings, and the most common complications.

Congenital short femur is a rare and complex deformity that is often associated with other anomalies. There are few reports of either hip or knee dislocations during femoral lengthening in congenital short femur predisposed by associated anomaly. However, there are probably no case reports of both hip and knee joint dislocation occurring in same case during femoral lengthening in congenital short femur. We have this case of congenital short femur, where both hip and knee dislocation occurs during femoral lengthening. We reviewed different article to understand the cause and avoid such unwanted complications in future.

Objective: The purpose of this study was to evaluate the incidence, cause, injury patterns, and MRI findings in knee dislocation in patients with normal and increased body mass index and to determine whether obesity interferes with knee MRI examinations., Materials and Methods: A retrospective study of the period from 2000 to 2007 (90 months) was performed at a level 1 trauma center, finding a total of 24 patients who had sustained a knee dislocation., Results: Twenty-two of the 24 patients underwent surgery and 19 patients had an MRI examination of diagnostic quality before surgery. Of the 24 patients, 11 had a body mass index greater than 25 and had knee dislocation due to low-energy trauma (nine due to a simple fall, two to a noncontact sport). Two of these 11 patients were morbidly obese (body mass index>40). These patients had no injuries to the popliteal tendon and they had no irreversible peroneal nerve injuries. Otherwise, the patients' injuries were in agreement with previous knee dislocation studies. Obesity did not interfere with knee MRI examinations. On the basis of the population served by our trauma center, the annual incidence of knee dislocation due to low-energy trauma in overweight patients is about 1.0 per million., Conclusion: The annual incidence in obese patients of knee dislocation due to low-energy trauma is not insignificant at a level 1 trauma center. As the prevalence of obesity increases, the injury patterns seen in emergency departments may change. The radiologist should be aware that even after a simple fall, overweight patients may have a knee dislocation.

Objectives: Our objectives were to determine retrospectively the prevalence, patients' demographics, mechanism of injury, combination of torn ligaments, associated intra-articular and extra-articular injuries, fractures, bone bruises, femoral-tibial alignment and neurovascular complications of knee dislocations as evaluated by magnetic resonance (MR) imaging., Materials and Methods: From 17,698 consecutive knee examinations by magnetic resonance imaging (MRI) over a 6-year period, 20 patients with knee dislocations were identified. The medical records of these patients were subsequently reviewed for relevant clinical history, management and operative findings., Results: The prevalence of knee dislocations was 0.11% [95% confidence interval (95% CI) 0.06-0.16)]. There were 16 male patients and four female patients, with ages ranging from 15 years to 76 years (mean 31 years). Fifteen patients had low-velocity injuries (75%), of which 11 were amateur sports related and four were from falls. Four patients (20%) had suffered high-velocity trauma (motor vehicle accidents). One patient had no history available. Anatomic alignment was present at imaging in 16 patients (80%). Eighteen patients had three-ligament tears, two had four-ligament tears. The four-ligament tears occurred with low-velocity injuries. The anterior cruciate ligament (ACL) and posterior cruciate ligament (PCL) were torn in every patient; the lateral collateral ligament (LCL) was torn in 50%, and the medial collateral ligament (MCL) in 60%. Intra-articular injuries included meniscal tears (five in four patients), fractures (eight in seven patients), bone bruises (15 patients), and patellar retinaculum tears (eight partial, two complete). The most common extra-articular injury was a complete biceps femoris tendon tear (five, 25%). There were two popliteal tendon tears and one iliotibial band tear. One patient had received a vascular injury following a motor vehicle accident (MVA) and had been treated prior to undergoing MRI. Bone bruises (unrelated to fractures), four-ligament tears, biceps femoris tears, and popliteus tendon tears were encountered only in the low-velocity knee dislocations. Twelve were treated surgically, five conservatively, and three had been lost to follow-up. The biceps femoris tendon was repaired in every patient who was treated surgically., Conclusions: Knee dislocations occurred more commonly in low-velocity injuries than in high-velocity injuries, predominantly affecting amateur athletes. Biceps femoris tendon tears were the most common extra-articular injury requiring surgery. Neurovascular injury (5%) was uncommon. At imaging, femoral-tibial alignment was anatomic in the majority of patients.

Objectives: The purpose of this study is to report the clinical and functional results of a cohort of patients with knee dislocations associated with vascular injury., Methods: Patients with knee dislocation and associated vascular injury were prospectively assessed for outcome of severe lower extremity trauma during 2 years. The Sickness Impact Profile was used to assess the functional recovery of the patient. Surgeon and therapist assessments documented clinical metrics and treatment, including salvage or amputation, neurologic recovery, knee stability, and knee motion., Results: Eighteen patients sustained a knee dislocation and an associated popliteal artery injury. Seven patients were found to have an additional vascular injury. All patients underwent repair of the vascular injury. At the time of final follow-up, 14 knees were successfully salvaged and four required amputation (1 below knee amputation, 2 through knee amputation, and 1 above knee amputation). Eighteen patients had at least a popliteal injury and underwent repair of the vascular injury. The patients with a limb-threatening knee dislocation that was successfully reconstructed had Sickness Impact Profile scores of 20.12 at 3 months, 13.18 at 6 months, 12.08 at 1 year, and 7.0 at 2 years after injury., Conclusions: Patients who sustain a limb-threatening knee dislocation have a moderate to high level of disability 2 years after injury. Nearly one in five patients who present to a Level I trauma center with a dysvascular limb associated with a knee dislocation will require amputation. Prolonged warm ischemia time was associated with a high rate of amputation. Patients who sustain vascular injuries associated with a knee dislocation need immediate transport to a trauma hospital, rapid assessment and diagnosis at presentation, and revascularization. Patients with these injuries can be effectively treated without angiography before surgery.

Posterolateral dislocations involve significant injury to the medial structures of the knee, therefore particular attention should be paid to repairing the medial patella stabilizers at the time of open reduction.

Background: Congenital Orthopaedic malformations are common malformations that are usually unacceptable to the common populace in the West African sub-region. There is paucity of knowledge about the common types of Orthopaedic congenital malformations in our environment This study was undertaken to determine the pattern of congenital Orthopaedic malformations in a Teaching Hospital., Study Design: This was a prospective study of all the Orthopaedic congenital malformations seen in our surgical outpatient departments and the inpatient referrals from the wards between January 1995 and December 2003., Result: There were 284 patients in total with a male to female ratio of 2:1 and age range between two days to nine years. Clubfoot (CTEV) accounted for 52.8% of all the malformations while Congenital knee dislocation (CDK) and calcaneovalgus deformity accounted for 8%. Congenital hip dislocation (CDH) accounted for only 2.2% of all the cases., Conclusion: Congenital talipes equinovarus deformity is the most common congenital orthopaedic malformation in this environment while congenital hip dislocation (CDH) is rare when compared with the Caucasians.

Objective: To determine the relationship of multiple variables, including the Injury Severity Score (ISS), closed head injury (CHI), and timing and type of surgery to formation of motion-limiting heterotopic ossification (HO) following knee dislocation., Design: Longitudinal observational study., Setting: University level 1 trauma center., Patients/participants: Thirty-five consecutive patients with 36 knee dislocations (OTA fracture and dislocation classification 40-D) admitted over a 26-month period., Main Outcome Measurements: Admission ISS, Glasgow Coma scale (GCS) scores, CHI, timing (> or < 3 weeks from injury) and type (open or arthroscopic) of surgery, number of cruciate ligaments reconstructed, medial surgical procedure, and eventual presence or absence of motion-limiting HO., Results: A classification system for HO was developed ranging from none (type 0) to ankylosing (type IV) HO. Twenty-nine patients with type 0-III HO recovered an average range of motion of 126 degrees at an average of 14 months (group A). Six patients formed ankylosing type IV HO (group B). The ISS in group A ranged from 9 to 26. ISS in group B ranged from 26 to 50 (P < 0.001). Regarding the formation of type IV HO, the sensitivity of an ISS >/=26 was 100%, the specificity was 97%, and the positive predictive value was 86%. Patients in group B had a greater incidence of documented CHI (P < 0.025). Timing and type of surgery, number of ligaments reconstructed, and whether or not the patient had a medial surgical procedure had no statistical influence on degree of HO formation., Conclusions: An ISS of 26 seems to be a discrete boundary above which patients with knee dislocation are at extremely high risk for type IV HO formation if undergoing surgical reconstruction and below which patients are likely spared this complication. The presence of a CHI is a significant factor in type IV HO formation, although harder to quantify. None of the remaining independent variables studied were significantly related to ankylosing type IV HO formation.

Between January 1996 and December 2001, 41 congenital dislocations of the knee joints (30 patients) were reduced with closed methods by immediate reduction without anaesthesia and serial casting in plaster of Paris immobilization for a period of six to eight weeks. The patients' age ranged from the age of one week to four weeks with a male to female ratio of 1.5:1. The right knee was involved in 46.65% the left in 16.6% and bilateral involvement in 36.65% of patients. Routine check of the hip did not reveal any patient with hip instability. All the patients followed up after 2 years showed excellent results. We conclude that congenital knee dislocation when discovered early and without any other congenital malformation can be managed conservatively with excellent results.