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Introduction: Dissociation of the knee joint, or knee dislocations (KD), can lead to severe complications, often resulting in multiligament injuries. A subset of these injuries are irreducible by closed reduction and require open reduction. Identifying KDs that necessitate surgical intervention is crucial for optimal outcomes. While previous studies have explored various risk factors, the influence of associated fractures is less understood., Materials and Methods: We queried the Trauma Quality Improvement Program (TQIP) database from 2017 to 2021, for non-congenital closed knee dislocations requiring surgery. Demographic variables were collected, and ICD-10 codes were used to identify associated tibia, femur, acetabular, and fibula fractures. ICD-10 codes were also used to identify nerve injuries and vascular injuries. Multivariate logistic regression was used to assess factors influencing the need for surgical reduction (SR)., Results: A total of 1,467 patients with KDs were included in the study, of which 411 (28.0%) underwent open surgical reduction (SR) while 1,056 (72.0%) were treated with nonsurgical closed reduction (nSR). Factors associated with SR included concomitant tibia fracture (OR = 1.683, C.I: 1.255-2.256, p < 0.001) and fibula fracture (OR = 1.457, C.I: 1.056-2.011, p = 0.022). Vascular injury had lower odds of SR (OR = 0.455, C.I: 0.292-0.708, p < 0.001)., Conclusion: Our study demonstrated that KDs presenting with concomitant tibia and/or fibula fractures are more likely to require SR. The difficulty posed to closed reduction may be due to the influence of these fracture patterns on surrounding soft tissue as well as the lack of a stable bone structure necessary for achieving proper reduction. Physicians should be aware of the potential risk of this fracture pattern when caring for patients with KDs., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Injury to the popliteal artery after knee dislocation, if not promptly diagnosed and properly treated, can have devastating results. The purpose of this retrospective study was to describe the diagnostic and the treatment protocol we use, as well as provide long-term outcomes for a series of patients treated in our tertiary hospital, emphasizing on the importance of ankle-brachial index (ABI) measurement as an integral component of the diagnostic approach., Methods: A retrospective analysis of all admissions to our hospital trauma center between November 1996 and July 2023, with a diagnosis of knee dislocation and the presence or absence of concomitant arterial injury resulting from blunt high-energy trauma, was conducted. Before 2006, digital subtraction angiography (DSA) and/or computed tomography angiography (CTA) were part of the diagnostic approach (group A). After 2006, the ABI was used as a first-line test to diagnose arterial damage (group B). The Tegner and Lysholm scores were chosen to assess patients' postoperative impairment between groups, taking also into account the presence or absence of vascular injury. The Mann-Whitney U test and a univariate analysis of variance were used for the statistical analysis of scores., Results: Overall, 55 patients were identified, and 21 of them (38.2%) had injuries to the popliteal artery, all of which were treated with a reversed great saphenous venous bypass. Out of the 21 patients, 4 (4.3%) developed compartment syndrome, which was treated with fasciotomies, and 1 leg (1.8%) was amputated above the knee. With no patients lost to follow-up, all but one (95%) of the vascular repairs are still patent, and the limbs show no signs of ischemia after a mean follow-up of 6 years. The Tegner and Lysholm score means were similar between groups A and B and independent of the presence of vascular injury and the diagnostic protocol used. Interestingly, an ABI below 0.9 proved to be predictive of arterial injury., Conclusions: A high level of awareness for the presence of popliteal artery injury should exist and an ABI measurement should be routinely performed in the management of all cases of knee dislocation. This way, fewer patients will undergo unnecessary CTA scanning, and hardly any popliteal artery injuries can go missing, as suggested by our study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background: Congenital dislocation of the knee is characterised by excessive knee extension or dislocation and anterior subluxation of the proximal tibia, and this disease can occur independently or coexist with different systemic syndromes. Nevertheless, significant controversy surrounds treating this disease when combined with hip dislocation. This paper presents a case of a 4-month-old patient diagnosed with bilateral hip dislocation combined with this disease. The study discusses the pathophysiology, diagnosis, and treatment methods and reviews relevant literature., Case Presentation: We reported a case of a 4-month-old female infant with congenital dislocation of the right knee joint, which presented as flexion deformity since birth. Due to limitations in local medical conditions, she did not receive proper and effective diagnosis and treatment. Although the flexion deformity of her right knee joint partially improved without treatment, it did not fully recover to normal. When she was 4 months old, she came to our hospital for consultation, and we found that she also had congenital dislocation of both hip joints and atrial septal defect. We performed staged treatment for her, with the first stage involving surgical intervention and plaster orthosis for her congenital dislocation of the right knee joint, and the second stage involving closed reduction and plaster fixation orthosis for her congenital hip joint dislocation. Currently, the overall treatment outcome is satisfactory, and she is still under follow-up observation., Conclusions: Early initiation of treatment is generally advised, as nonsurgical methods prove satisfactory for mild cases. However, surgical intervention should be considered in cases with severe stiffness, unresponsive outcomes to conservative treatment, persistent deformities, or diagnoses and treatments occurring beyond the first month after birth., (© 2024. The Author(s).)

Purpose: To describe our institutional experience and results in the surgical management of multiligament knee injuries (MLKI)., Materials and Methods: Retrospective series of MLKI consecutively operated on at a single, level I Trauma Center. Data on patients' baseline characteristics, injuries, treatments, and outcomes were recorded up to one-year follow-up. Recorded outcomes included the Tegner-Lysholm Knee Scoring Scale (TLKSS), return to work, and patient satisfaction., Results: MLKI incidence was 0.03% among 9897 orthopedic trauma admissions. Twenty-four patients of mean age 43.6 years were included in analysis. The mean Injury Severity Score was 12.6. Five patients presented with knee dislocations and six had fracture-dislocations, two of them open fractures. There was one popliteal artery injury requiring a bypass and four common peroneal nerve palsies. Staged ligamental reconstruction was performed in all cases. There were seven postoperative complications. The median TLKSS was 80 and, though patient satisfaction was high, and dissatisfaction was largely restricted to recreational activities (only 58.3% satisfied). Seventeen patients returned to their previous employment., Conclusions: We found a high aggregation of fracture-dislocations secondary to road traffic accidents. One in four patients experienced complications, particularly stiffness. Complications were more common in cases involving knee dislocation. Most patients had good functional results, but 25% were unable to return to their previous work, which demonstrates the long-lasting sequelae of this injury., (© 2023. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

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.)

Background: Knee fracture-dislocations are complex injuries; however, there is no universally accepted definition of what constitutes a fracture-dislocation within the Schenck Knee Dislocation (KD) V subcategory. The purpose of this study was to establish a more precise definition for fracture patterns included within the Schenck KD V subcategory., Methods: A series of clinical scenarios encompassing various fracture patterns in association with a bicruciate knee ligament injury was created by a working group of 8 surgeons. Utilizing a modified Delphi technique, 46 surgeons from 18 countries and 6 continents with clinical and academic expertise in multiligamentous knee injuries undertook 3 rounds of online surveys to establish consensus. Consensus was defined as ≥70% agreement with responses of either "strongly agree" or "agree" for a positive consensus or "strongly disagree" or "disagree" for a negative consensus., Results: There was a 100% response rate for Rounds 1 and 2 and a 96% response rate for Round 3. A total of 11 fracture patterns reached consensus for inclusion: (1) nondisplaced articular fracture of the femur; (2) displaced articular fracture of the femur; (3) tibial plateau fracture involving the weight-bearing surface (with or without tibial spine involvement); (4) tibial plateau peripheral rim compression fracture; (5) posterolateral tibial plateau compression fracture, Bernholt type IIB; (6) posterolateral tibial plateau compression fracture, Bernholt type IIIA; (7) posterolateral tibial plateau compression fracture, Bernholt type IIIB; (8) Gerdy's tubercle avulsion fracture with weight-bearing surface involvement; (9) displaced tibial tubercle fracture; (10) displaced patellar body fracture; and (11) displaced patellar inferior pole fracture. Fourteen fracture patterns reached consensus for exclusion from the definition. Two fracture patterns failed to reach consensus for either inclusion or exclusion from the definition., Conclusions: Using a modified Delphi technique, this study established consensus for specific fracture patterns to include within or exclude from the Schenck KD V subcategory., Level of Evidence: Prognostic Level V . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H586 )., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

The aim of this study was to compare outcomes of tibial plateau fracture dislocations (FD) with tibial plateau fractures alone. This study was an analysis of a series of tibial plateau fractures, in which FD was defined as a fracture of the tibial plateau with an associated loss of congruent joint reduction and stability of the knee, and classified by the Moore system. Patient data collected included demographics, injury information, and functional outcomes (short musculoskeletal function assessment [SMFA] score and Pain by the visual analog scale). Clinical outcomes at follow-up were recorded including knee range of motion, knee stability and development of complications. There were a total of 325 tibial plateau fracture patients treated operatively, of which 22.2% were identified as FD ( n  = 72). At injury presentation there was no difference with regard to nerve injury or compartment syndrome (both p  > 0.05). FD patients had a higher incidence of arterial injury and acute ligament repair (both p  < 0.005). At a mean follow-up of 17.5 months, FD patients were similar with regard to pain, total SMFA scores, and return to sports than their non-FD counterparts ( p  = 0.884, p  = 0.531, p  = 0.802). FD patients were found to have decreased knee flexion compared with non-FD patients by 5 degrees (mean: 120 and 125 degrees) ( p  < 0.05). FD patients also had a higher incidence of late knee instability and subsequent surgery for ligament reconstruction ( p  < 0.005 & p  < 0.05). However, there was no difference in neurological function between groups at follow-up ( p  = 0.102). Despite the higher incidence of ligamentous instability and decreased range of motion, FD patients appear to have similar long-term functional outcomes compared with non-FD of the tibial plateau. While FD patients initially presented with a higher incidence of arterial injury, neurovascular outcomes at final follow-up were similar to those without a dislocation., Competing Interests: None declared., (Thieme. All rights reserved.)

Posterior knee dislocations (PKD) in children are uncommon but may be associated with vascular injury. The purpose of this study is to characterize the frequency of vascular injury in PKD as well as define patient characteristic, procedures, types of treating hospitals, and clinical outcomes. This study utilized the National Trauma Data Set (NTDS) from the American College of Surgeons on years 2015 and 2016. All demographic and clinical data on pediatric patients (≤18 years) with the ICD codes for PKD were obtained. 44 PKD were identified. The median age was 17 years [IQR 15,18], 70% male; 49% white. The mean body mass index was 29.6 [IQR 23-38]. We found that vascular injury was present in 16 patients (36%); 14 (30%) underwent repair (eight with saphenous vein graft) and fasciotomies in eight patients. Nerve injury was present in five patients (11%). Lower extremity amputation was performed in three patients (7%).

A 48-year-old male patient presented with inner skin retraction after a sports accident involving the knee. In a multi-ligament injury it must be assumed that knee dislocation has occurred. Inner skin retraction after knee distortion can result from an intra-articular dislocation of the ruptured medial collateral ligament. Prompt reduction and exclusion of concomitant neurovascular injuries is thus obligatory. After surgical reconstruction of the medial collateral ligament, instability was no longer apparent 3 months postoperatively., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Background: Multiple ligament knee injuries (MLKIs) represent a spectrum of injury patterns that are often associated with concomitant musculoskeletal and neurovascular injuries, complex treatment, and postoperative complications. However, there has not been high-level evidence describing the presentation and treatment of MLKIs. The purpose of this multicenter retrospective study was to describe characteristics of MLKIs, their management, and related complications using a pathoanatomic MLKI classification system based on the Schenck Knee Dislocation classification system., Methods: This review identified and analyzed MLKIs that occurred between 2011 and 2015. Cases with an MLKI were included in this study if there was a complete tear of ≥2 ligaments and at least 1 ligament was repaired or reconstructed. Cases in which a ligament was deemed clinically incompetent due to a partial ligament tear and required surgical repair or reconstruction were considered equivalent to grade-III tears for inclusion and classification. Demographic information, the mechanism of injury, times from injury to presentation to an orthopaedic surgeon and to surgery, the ligament injury pattern, associated injuries, surgical procedures, and complications were captured. Data were analyzed descriptively., Results: A total of 773 individuals from 14 centers who underwent surgery for an MLKI were reviewed. The mean age of the individuals was 30.5 ± 12.7 years, and 74.2% were male. The most common mechanism involved sports (43.2%). The median time from injury to presentation to the orthopaedic surgeon was 11 days (interquartile range [IQR], 3 to 48 days), and the time to initial ligament surgery was 64 days (IQR, 23 to 190 days). While the most common injury patterns were an anterior cruciate ligament tear combined with either a medial-sided (MLK 1-AM, 20.7%) or lateral-sided (MLK 1-AL, 23.2%) injury, one-third (34.7%) were bicruciate injuries. Associated injuries most often involved menisci (55.6%), nerves (18.5%) and tendons (15.6%). The method of surgical intervention (repair versus reconstruction), external fixator use, and staging of procedures varied by MLKI classification. Loss of motion (11.4%) was the most common postoperative complication., Conclusions: A better understanding of the clinical characteristics and management of the various MLKI patterns can be used to support clinical decision-making and individualized treatment of these complex injuries, and may ultimately lead to enhanced outcomes and reduced associated risks., Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article ( http://links.lww.com/JBJS/H440 )., (Copyright © 2023 Written work prepared by employees of the Federal Government as part of their official duties is, under the United States Copyright Act, a “work of the United States Government” for which copyright protection under that Act is not available. As such, copyright protection does not extend to the contributions of employees of the Federal Government prepared as part of their employment.)

»: Traumatic knee dislocations are complex injuries that can be associated with compromise of the neurovascular structures about the knee., »: Various classification systems for knee dislocations exist in the literature but should be used with caution as a prognostic tool because many knee dislocations fit into more than 1 category., »: Special populations of knee dislocations, such as obese patients and high-velocity mechanism injuries, require additional caution during the initial evaluation for possible vascular injuries., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSREV/A937)., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Introduction: Multisystem injuries affecting vasculature and nerves can be detrimental sequelae of knee dislocations (KDs). The purpose of this study was to provide an update of the current literature since the conducted search used in the publication of Medina et al on May 3, 2013, to evaluate (1) the frequency of vascular and neurologic injury after KD, (2) the frequency with which surgical intervention was conducted for vascular injury in this setting, and (3) the frequency with which each imaging modality was used to detect vascular injury., Methods: A two-author screening process was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the MEDLINE database. Frequency of vascular injury, surgical intervention, and amputation after KD were analyzed. Diagnostic modalities used in the acute-care setting were also evaluated., Results: Nineteen articles were analyzed for a total of 37,087 KDs. Of these, 10.7% sustained vascular injuries and 19.6% sustained nerve injuries. Overall, 62.2% of patients with vascular injury underwent surgical repair and 2.2% limbs resulted in amputation. Angiography was the most frequently used diagnostic modality (91.7%)., Discussion: This review updates our understanding on the clinical implications of KDs including frequency of vascular injury (10.7%), amputation (2.2%), and nerve injuries (19.6%). Compared with prior literature, there was an increased prevalence of KD1 (32.4%) and lateral KDs (80.4%). Most vascular injuries after KD undergo surgical repair (62.2%)., (Copyright © 2022 by the American Academy of Orthopaedic Surgeons.)

Case: A 19-year-old man sustained combined, ipsilateral inferior hip and posterior knee fracture-dislocations secondary to a motor vehicle collision. He underwent immediate closed reduction of the knee and delayed open reduction internal fixation but required emergent open hip reduction for an irreducible femoral head incarcerated on a pubic root fracture. At the 1-year follow-up, he demonstrated excellent functional outcome with painless and full hip and knee range of motion., Conclusion: Irreducible inferior femoral head dislocation in combination with a knee dislocation requires thoughtful staging and treatment but can result in satisfactory outcomes., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/C18)., (Copyright © 2023 by The Journal of Bone and Joint Surgery, Incorporated.)

Multiligamentous knee injuries (MLKI) are rare but devastating injuries that have a potential to cause long-term sequelae and significant morbidity. Frequently occurring concomitantly with knee dislocations (KD), MLKI have many risk factors that influence their incidence and treatment outcomes. Proper understanding of these risk factors can assist the surgeon with evaluation, surgical planning, and managing patient expectations both pre- and postoperatively. The purpose of this review is fourfold: (1) identify the risk factors and injuries associated with MLKI, (2) describe factors implicated in the treatment of MLKI, (3) report the effect of these risk factors on outcomes of MLKI, and (4) provide a brief insight into MLKI at our tertiary referral academic care center. This was a retrospective review of literature relevant to MLKI. Studies that described injuries, risk factors, treatment techniques, or outcomes associated with MLKI were included in our review. A total of 35 studies (consisting of level 3 and 4 evidence) published between 2009 and 2020 were found and included in our analysis. In addition, 25 patients who underwent treatment for MLKI at the University of Chicago Medical Center between December 2015 and December 2019 were included in our analysis. MLKI tend to occur in the younger male population. Increasing age, body mass index, and severity of the injury have been correlated with worse functional and patient-reported outcomes. Operative treatment is indicated for MLKI; however, timing and repair versus reconstruction is still debated, and is often decided on a patient by patient basis. Retrospective cohort studies have indicated that reconstruction may be favored; however, further more rigorous studies are needed to better characterize this finding. MLKIs are devastating injuries with significant variability in presentation, treatment, and outcome. Variations in these are largely attributable to the mechanism and severity of injury, timing, and surgeon preference. A holistic approach, and understanding of the present literature, is required to best optimize patient outcome., Competing Interests: None declared., (Thieme. All rights reserved.)

Objectives: Knee dislocations (KDs) are complex injuries defined as incongruity of the tibiofemoral joint, which leads to tears of two or more of the main stabilising knee ligaments, and they are often associated with damage to surrounding soft tissue or neurovascular structures. A classification system for these injuries should be simple and reproducible and allow communication among surgeons for surgical planning and outcome prediction. The aim of this study was to formulate a list of factors, prioritised by high-volume knee surgeons, that should be included in a KD classification system., Methods: A global panel of orthopaedic knee surgery specialists participated in a Delphi process. The first survey employed 91 orthopaedic surgeons to generate a list of patient- and system-specific factors that should be included in a KD classification system that may affect surgical planning and outcomes. This list was subsequently prioritised by 27 identified experts (mean 15.3 years of experience) from Brazil (n = 9), USA (n = 6), South Africa (n = 4), India (n = 4), China (n = 2), and the United Kingdom (n = 2). The items were analysed to find factors that had at least 70% consensus for inclusion in a classification system., Results: Of the 12 factors identified, four (33%) achieved at least 70% consensus for inclusion in a classification system. The factors deemed critical for inclusion in a classification system included vascular injuries (89%), common peroneal nerve injuries (78%), number of torn ligaments (78%), and open injuries (70%)., Conclusion: Consensus for inclusion of various factors in a KD classification system was not easily achieved. The wide geographic distribution of participants provides diverse insight and makes the results of the study globally applicable. The most important factors to include in a classification system as determined by the Delphi technique were vascular injuries, common peroneal nerve injuries, number of torn ligaments, and open injuries. To date, the Schenck anatomic classification system most accurately identifies these patient variables with the addition of open injury classification. The authors propose to update the Schenck classification system with the inclusion of open injuries as an additional modifier, although this is only a small step in updating the classification, and further studies should evaluate the inclusion of more advanced imaging modalities. Future research should focus on integrating these factors into useful existing classification systems that are predictive of surgical treatment and patient outcomes., Competing Interests: Declaration of competing interest D.CW. is a member of the ISAKOS Board of Directors. The other authors have no competing interest to declare., (Copyright © 2022 The Author(s). Published by Elsevier Inc. All rights reserved.)

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., (© 2021. ISS.)

The present study aims to investigate whether there is a relationship between the ligamentous injury pattern and concomitant neurovascular injury with long-term functional outcomes in patients with traumatic knee dislocations (TKDs). A total of 42 patients with TKDs were categorized according to the Schenck's classification based on the pattern of ligamentous injury. Concomitant vascular and neural injuries were recorded. Long-term functional outcomes were assessed using several objective and subjective outcome measures. This retrospective study was conducted in two phases: (1) to analyze the impact of ligamentous injury pattern on functional outcomes of patients with TKDs in the overall study population, by comparing all the variables among Schenck's grades; (2) to determine the impact of concomitant vascular and neural injury on ultimate knee function based on the subgroup analyses. In the overall study statistical differences were determined among each pattern of ligamentous injury in the total range of motion (ROM) and scoring systems (chi-squared test, p  = 0.254). The overall rates of vascular and neural injury were 26 and 28%, respectively. In subgroup analyses, 40 patients were divided into three subgroups: group A (isolated concomitant neural injury), group B (isolated concomitant vascular injury), group C (without concomitant major vascular or neural injury). The analysis revealed a significant difference in the total ROM ( p  = 0.005), flexion measurements ( p  = 0.004), and the loss of extension ( p  = 0.003). Group A had the lowest total knee ROM and the mean flexion degrees, as well as the highest loss of extension. Concerning functional scoring systems including the combined Knee Society Score (knee score + function score), Lysholm knee scoring scale, and International Knee Documentation Committee score, subgroup analyses revealed significant differences among the groups ( p  = 0.001, p  < 0.01 for all scores). All the scores were found to be lowest in group A. Evidence from the current study showed that the ligamentous pattern and concomitant neurovascular injury both may have a significant impact on ultimate knee function in patients with TKDs. This is a Level III-retrospective comparative study., Competing Interests: None declared., (Thieme. All rights reserved.)

Update: This article was updated on May 19, 2021 because of previous errors, which were discovered after the preliminary version of the article was posted online. In the legend for Figure 3-A, the phrase that had read "T1-weighted coronal MRI showing a right knee" now reads "T1-weighted coronal MRI showing a left knee." On page 924, in the section entitled "Materials and Methods," the sentence that had read "If there was no radiographic evidence or if there was a clinical note that documented visible deformity around the knee with no reduction maneuver being performed, then the patient was classified into the non-dislocated MLKI group." now reads "If there was no radiographic evidence or if there was no clinical note that documented visible deformity around the knee with no reduction maneuver being performed, then the patient was classified into the non-dislocated MLKI group." On page 925, in the section entitled "Analysis," the sentence that had read "Our study included 78 dislocated MLKIs and non-dislocated MLKIs, so both cohorts were adequately powered for the overall analysis." now reads "Our study included 45 dislocated MLKIs and 78 non-dislocated MLKIs, so both cohorts were adequately powered for the overall analysis." Finally, on page 927, in the section entitled "Discussion," the sentence that had read "Interestingly, we found that MLKIs with a documented knee dislocation had a substantially higher rate of vascular injury (23%) compared with those without (3%)." now reads "Interestingly, we found that MLKIs with a documented knee dislocation had a substantially higher rate of vascular injury (18%) compared with those without (4%).", Competing Interests: Disclosure: The authors indicated that no external funding was received for any aspect of this work. On the Disclosure of Potential Conflicts of Interest forms, which are provided with the online version of the article, one or more of the authors checked “yes” to indicate that the author had a relevant financial relationship in the biomedical arena outside the submitted work (http://links.lww.com/JBJS/G345)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Case: A 29-year-old healthy woman, 19 weeks pregnant, sustained a right posterolateral knee dislocation with multiligamentous injury and a complete occlusive injury to the right popliteal artery yet had adequate distal perfusion. She declined operative management for both the knee dislocation and the arterial injury, and successful collaboration between obstetrical, vascular, and orthopaedic surgical services resulted in limb preservation and restoration of function., Conclusion: This is a unique case of traumatic complete popliteal artery occlusion with adequate collateral arterial perfusion after a reducible posterolateral knee dislocation in a pregnant patient that resulted in limb preservation with nonoperative management., Competing Interests: Disclosure: The Disclosure of Potential Conflicts of Interest forms are provided with the online version of the article (http://links.lww.com/JBJSCC/B427)., (Copyright © 2021 by The Journal of Bone and Joint Surgery, Incorporated.)

Objective: Arterial injury in knee trauma is rare but can be devastating if the diagnosis is delayed. The frequency of concomitant arterial injury resulting from knee dislocations remains unclear, and from knee fractures it remains unknown. The primary aim was to investigate the incidence of arterial injury in knee trauma requiring hospitalisation. Secondary aims were to identify risk factors and describe outcome., Methods: Traumatic popliteal artery injury and knee trauma were identified by International Classification of Diseases (ICD)-10 codes from the Swedish National Inpatient registry (NPR), 1998-2014 and linked with data using the unique personal identification number with the National Registry for vascular surgery (Swedvasc). Risk factors for popliteal artery injury (PAI) such as cause of injury, comorbidities and injury severity were extracted from the NPR. Socio-economic status data and population count came from Statistics Sweden, and cause and date of death from the Swedish Cause of Death Registry., Results: A total of 71 149 admissions due to all knee trauma were identified, and 359 with simultaneous PAIs. Some of those injuries were non-orthopaedic. The proportion of PAI after knee dislocation ranged between 3.4% (46/1370 dislocations or multiligamentous injuries) and 8.2% (46/564 dislocations), and 0.2% after fracture close to the knee (60/36 483). The most common causes of injury with PAI were falls causing knee dislocations and motor vehicle accidents (MVAs) causing fractures. The fact that all 46 injuries occurring after multiligamentous injuries were classified as knee dislocations is probably explained by the fact that the ICD codes are chosen retrospectively when the patient leaves the hospital., Conclusion: PAI after knee dislocation is not uncommon, and most frequently caused by a fall. PAI associated with knee fracture is rare and mostly caused by a MVA, while in low energy knee fractures PAI is practically non-existent., (Copyright © 2021 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Severe varus deformity and soft tissue injury caused by a burn around a complex knee dislocation is a rare injury. Soft tissue reconstruction and deformity correction with circular hexapod external fixation of the knee and hinged total knee arthroplasty (TKA) are challenging and can lead to major complications if not performed appropriately. We present a case in which a combination of soft tissue reconstruction, circular hexapod external fixation, and TKA was used treat severe knee dislocation due to burn scarring., Case Presentation: We report the case of a 58-year-old woman who presented for knee surgery with soft tissue reconstruction, deformity correction with circular hexapod external fixation, and hinged TKA for a severe complex deformity and soft tissue injury caused by a burn injury at 6 months of age. The left leg was shorter by 35 mm in terms of functional leg length discrepancy. She walked with a limp, with a marked varus deformity of the left knee during the stance phase of walking. After a 3-stage repair, the patient was able to walk without assistance, confirming improvement of mobility., Conclusion: The treatment method was an effective use of a combination of soft tissue reconstruction, circular hexapod external fixation, and rehearsal surgery using a 3D printed bone model of the modular rotating hinge component of TKA, which was successfully used to treat a severe knee dislocation due to burn scarring. This staged surgery maintained the leg length and ultimately achieved a satisfactory alignment.

Knee dislocations (KDs) are frequently found in high-energy impact injuries, ranging from automobile accidents to contact sports. KDs require careful examination due to the limb-threatening nature of these injuries. A key examination in any KD comprises a proper assessment of the vascular status. The risk of popliteal artery injury with a KD has varied from 7 to 40%, with more contemporary studies reporting injury in the range of 7 to 15%. The notion of mandatory emergent arteriography was challenged in the trauma literature as several small retrospective studies suggested that selective arteriography was a safe and effective treatment protocol. New imaging modalities have evolved and have found their way into trauma surgery. Computed tomography angiography and magnetic resonance angiography are two contemporary imaging modalities that have different characteristics as well as availability. Arteriography has been the gold standard and is a reliable and proven method of evaluation. However, it has a number of negative aspects that must be considered when determining the ideal imaging for a patient following KD. Besides cost savings of about more than US$500,000, conventional arteriography, which comprises the use of X-ray, arterial puncture and cannulation, and the use of contrast agents containing iodine, has got a complication rate as high as 9% and more patient discomfort compared with the new imaging modalities. This clinical practice review documents that our algorithm of clinical examination first combined with advanced imaging in cases with abnormalities documented on examination is a safe and prudent policy in treating patients following KD., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

The multiple ligament injured knee (knee dislocation) is, often times, part of a multisystem injury complex that can include not only injuries to knee ligaments but also to blood vessels, skin, nerves, bones (fractures), head injuries, and other organ system trauma. These additional injuries can affect surgical timing for knee ligament reconstruction and also affect the results of the treatment. This article will present the author's approach and experience in the initial assessment and treatment of the acute multiple ligament injured (dislocated) knee, and also present considerations in the treatment of chronic multiple ligament injured knee., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Knee dislocations are rare but devastating injuries that can often be associated with concomitant nerve injury, most often of the common peroneal nerve. Prompt diagnosis, investigation, and appropriate treatment are important in this subset of patients. This article provides an overview of relevant injury demographics, anatomy, diagnosis, and prognosis, and suggests a treatment algorithm for nerve injury associated with multiligament knee injury., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

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.

Background: Common peroneal nerve (CPN) injury following a knee dislocation is a serious problem, and an optimal treatment is yet to be established. We report a case of complete CPN palsy following a knee dislocation treated with sural nerve grafting., Case: A 19-year-old man suffered a knee injury during a hurdle race. Diagnosis in a previous hospital revealed a complex ligament injury with CPN palsy. Ten weeks following injury, he was admitted to our institution because of a lack of neurological improvement. Considering the grade 0 results obtained in the manual muscle test (MMT) of tibialis anterior (TA) and extensor hallucis longus (EHL), the patient was diagnosed with complete neurotmesis of CPN, and surgery was performed. Operative findings revealed CPN discontinuity and an extended nerve defect length of 15 cm; therefore, sural nerve grafting was performed to repair the CPN injury. One year postoperatively, a grade 1 result from MMT of TA and EHL indicated a gradual neurological recovery. Three years postoperatively, MMT of TA and EHL showed significant improvement to grade 4+ and grade 4, respectively, and he could walk and jog without a knee brace., Discussion: Nerve graft length of >6 cm has shown limited success, and their efficacy for the treatment of CPN palsy following knee dislocations is controversial. However, young patients with complete CPN lesion are more likely to recover regardless of the length of nerve injury. Therefore, in such cases, nerve grafting can be considered as one of the treatments for complete CPN lesion following knee dislocations.

Case: A 43-year-old man suffered an irreducible posterolateral knee dislocation while snowboarding with associated tears of the anterior cruciate, posterior cruciate, medial collateral, and posterolateral corner ligaments. Two closed reduction attempts failed, and magnetic resonance imaging revealed incarcerated soft tissue from a tertiary gastrocnemius muscle head. The patient underwent open reduction and repair/reconstruction of his multiligamentous knee injury. At the 6-year follow-up, the patient did not have pain or instability and returned to recreational activities., Conclusions: This case demonstrates that a tertiary gastrocnemius muscle head, the most common anatomical variation, may complicate the closed reduction of an irreducible posterolateral knee dislocation.

This case presents a patient who sustained a knee dislocation, and who due to her diagnosis of sarcoidosis, other comorbidities, and prolonged use of corticosteroids, external fixation and physical therapy were implemented versus soft tissue reconstruction/repair. Research indicates worse functional outcomes with non-surgical treatment, and guidelines on optimising outcomes in this population are lacking. Integrated care of the patient-even when complex injuries and comorbid medical conditions are present-can lead to positive functional recovery, despite previous data. Evidence from related injuries can be successfully adapted in non-surgical management of these injuries, providing general treatment guidelines., Competing Interests: Competing interests: None declared., (© BMJ Publishing Group Limited 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Arthrofibrosis can be a devastating complication after ligamentous knee reconstruction. Beyond early range of motion (ROM), manipulation under anesthesia (MUA) and arthroscopic lysis of adhesions (LOAs) are the most frequently employed interventions for the condition. There is a paucity of data regarding predictive factors of arthrofibrosis requiring MUA and LOA, and even less data regarding changes in validated patient-reported outcome measures following the procedure. A retrospective case-control study was performed at an academic, urban Level I trauma center of patients that developed arthrofibrosis requiring MUA and LOA following ligamentous reconstruction. The indication for LOA was failure to achieve a 90° arc of ROM by 6 weeks. Seventeen cases and 141 controls were identified. Follow-up for cases was 26.9 ± 17.1 months (mean ± standard deviation). Time from initial reconstruction to LOA was 75.2 ± 27.9 days. Cases had higher body mass indices by a mean of 2.9 ( p  = 0.024). The most significant risk factors for stiffness were concomitant anterior cruciate ligament, posterior cruciate ligament, and posterolateral corner/lateral collateral ligament injury (odds ratio [OR], 17.08), knee dislocation (OR, 12.84), and use of an external fixator (OR, 12.81, 95% confidence interval [CI], 3.03-54.20) (all p  < 0.0026). Mean Knee Injury and Osteoarthritis Outcome Scores, Western Ontario and McMaster Universities Osteoarthritis Indices, and International Knee Documentation Committee scores improved by 47.5, 50.5, and 47.3% (all p  < 0.0038), respectively. All patients reported improvement in pain, with maximum daily pain scores improving by a mean of 4.1 points on the Numeric Pain Rating Scale ( p  < 0.001). Mean ROM arc improved by 38.8° ( p  < 0.001). All 17 cases were satisfied with the procedure. Twelve cases (70.59%) reported a full return to preinjury level of activity. No factors were identified that predicted success from the procedure, likely due to inadequate sample size. Arthrofibrosis following knee injury and ligamentous reconstruction can be predicted by the severity of injury and early intervention with MUA and arthroscopic LOA can lead to a satisfactory outcome for the patient., Competing Interests: None declared., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Introduction: Common peroneal nerve (CPN) injury occurs in 10-40% of patients following knee dislocation. Is magnetic resonance imaging (MRI) using routine knee protocols able to adequately evaluate CPN injury and predict long-term outcome?, Methods: Trauma patients presenting for knee MRI at a single public hospital, between July 2007 and May 2017, were retrospectively identified using radiology and orthopaedic databases. Medical records were retrieved for clinical scores. MRI images were scored by two independent radiologists blinded to the clinical CPN status and scores correlated with initial clinical scores using the Pearson correlation coefficient., Results: Final cohort included 107 patients (81 males and 26 females) with a mean age of 39 (range 19-81 years). MRI was considered to be adequate for coverage of the CPN in 84 patients. Fourteen patients had CPN injury clinically (seven complete and seven partial). Concordance between MRI scores and initial clinical scores was 0.456 (P = 0.01). MRI sensitivity and specificity for CPN injury on the 84 adequate scans were 54.5% and 93.2% respectively. All seven cases of partial CPN injury and three of seven cases of complete CPN injury recovered fully. High MRI scores of 5 and 8 were given for the two patients with a persisting complete CPN palsy. Highest scores for partial CPN injury subjects were 2 and 4., Conclusions: Magnetic resonance imaging using a routine knee protocol is not adequate for the assessment of CPN injury in many subjects. More specific MRI neural sequences with complete CPN coverage may be worth trialing., (© 2018 The Royal Australian and New Zealand College of Radiologists.)

Traumatic knee dislocation is a rare but potentially limb-threatening injury. Thus proper initial diagnosis and treatment up to final ligament reconstruction are extremely important and a precondition to successful outcomes. Reports suggest that evidence-based systematic approaches lead to better results. Because of the complexity of this injury and the inhomogeneity of related literature, there are still various controversies and knowledge gaps regarding decision-making and step-sequencing in the treatment of acute multi-ligament knee injuries and knee dislocations. The use of ankle-brachial index, routine or selective angiography, braces, joint-spanning or dynamic external fixation, and the necessity of initial ligament re-fixation during acute surgery constitutes current topics of a scholarly debate. The aim of this article was to provide a comprehensive literature review bringing light into some important aspects about the initial treatment of knee dislocation (vascular injury, neural injury, immobilization techniques) and finally develop an accurate data-based universal algorithm, enabling attending physicians to become more acquainted with the management of acute knee dislocation.

Purpose: The purpose of this study is to describe the prevalence and associated factors of anterolateral ligament (ALL) injury in knee dislocation (KD)., Methods: A retrospective review of charts and radiological images was done for patients who underwent multiligamentous knee reconstruction surgery for KD in the authors' institution from May 2008 to December 2016. The inclusion criteria were both genders, skeletally mature, and first dislocation. Previous anterior cruciate ligament injury or surgery were the exclusion criteria. Magnetic resonance imaging was used to describe the ALL injury. The association of ALL injury with other variables related to the injury and the patient's background features was examined., Results: Forty-eight patients (49 knees) were included. The mean age of the patients was 32.3 ± 10.6 years. High-energy trauma was the mechanism of dislocation in 28 (57.1%) knees. Thirty-one knees (63.3%) were classified as KD type IV. Forty-five (91.8%) knees had a complete ALL injury, and 3 (6.1%) knees had incomplete ALL injury. Forty (81.6%) knees had a complete ALL injury at the proximal fibers of the ALL, while 23 (46.9%) knees had complete distal ALL injury. None of the 46 (93.9%) knees with lateral collateral ligament injury had normal proximal ALL fibers (P = .012). Injury to the distal fibers of the ALL, as well as overall ALL injury, was not associated with any other variables (P > .05). Moreover, all patients with associated tibial plateau fractures (9; 18.4%) had abnormality of the proximal fibers of the ALL (P = .033)., Conclusions: ALL injury is highly prevalent among dislocated knees. Most of the injuries are of high grade and involve the proximal, suprameniscal, fibers of the ligament., Level of Evidence: Level IV, retrospective case series with no comparison group., (Copyright © 2018 Arthroscopy Association of North America. All rights reserved.)

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.

Objective: The purpose of this study was to report the clinical and functional results of patients who underwent surgical management for posterior knee dislocation associated with extensor apparatus rupture., Introduction: Posterior knee dislocations associated with extensor apparatus ruptures are defined as rare but complicated injuries, which are difficult to return to the level of activity prior to the injury. The study demonstrated a hypothesis that good knee stability and early gain of range of motion could be achieved with deliberate design of the treatment protocol and proper application of the instruments., Methods: Fifteen patients with posterior knee dislocations associated with extensor apparatus ruptures were evaluated after reduction and repair of extensor apparatus. Following that, multiple-ligament reconstruction in association with use of a lateral knee-spanning external fixator was applied for at least six weeks. Ligament reconstructions were performed using allografts. Range of motion and knee stability were both measured at each follow-up evaluation at a mean time of 36months. The assessment was made using the Lysholm Knee Scoring Scale., Results: The mean Lysholm scale score was 87.6 (range 73-95), with excellent in 11 cases, good in two, and fair in two. In the final evaluation, the range of motion was a mean range of 123.4° (range 100-135)., Conclusion: The use of a lateral knee-spanning external fixator ensured the safety of repaired vessels, knee stability after reduction, and early rehabilitation with range of motion., (Copyright © 2017. Published by Elsevier B.V.)

Background: Whether early or delayed surgical intervention in patients with multi-ligament injuries results in better outcomes, is of current and controversial debate., Purpose: The purpose of this study was to perform a meta-analysis comparing early versus late surgical treatment of multi-ligament knee injuries., Methods: We performed a systematic review of Medline, Embase, Scopus, and Google Scholar to identify relevant studies in the English and German literature. Eligibility criteria included studies comparing early or delayed surgical interventions for multi-ligament knee injuries, with a minimum follow-up of two years, reporting the primary clinical outcome using a validated functional scoring system and range of motion. Exclusion criteria were patients treated with multi-trauma, head injury, non-union, lower extremity fractures, or a documented history of previous knee injuries. Publication bias was assessed by funnel plot, and the risk of bias was established using the Cochrane Collaboration's risk of bias tool. Heterogeneity was assessed using χ 2 and I 2 statistic., Results: Eight studies (n=260 patients) were included in the analysis. 149 patients were treated early with a mean of 10.6days; 111 patients were treated late with a mean of 294days. The pooled estimate for clinical outcome demonstrated that early surgery resulted in significantly higher Lysholm scores (SMD 0.669, 95% CI: 0.379 to 0.959, p=0.0001, I 2 =0%). Thirty-one per cent of all patients with early surgery had a normal or near normal knee, whereas only 15% of patients with late reconstruction reported the knee to be normal or near normal. The pooled estimates for total ROM did not demonstrate a significant difference between the groups (SMD 0.113, 95% CI: -0.271 to 0.498, p=0.564, I 2 =35.57%)., Conclusions: The results of this meta-analysis suggest that early surgical intervention in multi-ligament injuries of the knee produces a significantly superior clinical outcome, compared to late reconstruction. Although an overall trend of improved total range of knee motion was also demonstrated, this was very small and unlikely to be clinically relevant., Level of Evidence: Level 4; Systematic review and meta-analysis., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Knee dislocation is a relatively rare condition of all orthopaedic injuries. Accompanying multiple ligament injuries are common after knee dislocations. A 41-year-old male presented to the emergency department suffering from right knee dislocation in June 2013. The patient had anterior cruciate ligament, medial collateral ligament (MCL), medial patellofemoral ligament (MPFL) rupture, and lateral meniscal tear. A single-bundle anatomic reconstruction, medial collateral ligament reconstruction, medial patellofemoral ligament reconstruction and meniscus repair were performed in single session. At twelve months follow-up; there was 160º flexion and 10° extension knee range of motion. Lysholm knee score was 90. Extensive forces can cause both MCL and MPFL injury due to overload and the anatomical relationship between these two structures. Therefore, patients with valgus instability should be evaluated for both MPFL and MCL tears to facilitate successful treatment.

Background: Knee dislocations are rare injuries with potentially devastating vascular complications. An expeditious and accurate diagnosis is necessary, as failing to diagnose vascular injury can result in amputation; however, the best diagnostic approach remains controversial., Questions/purposes: We asked: (1) What patient factors are predictors of vascular injury after knee dislocation? (2) What are the diagnostic utilities of palpable dorsalis pedis or posterior tibial pulses, and the presence of an ankle-brachial index (ABI) of 0.9 or greater?, Methods: A database at a Level I trauma center was queried for patients with evidence of knee dislocation, demographic information (age at the time of injury, sex, Injury Severity Score, BMI, mechanism of injury), and the presence of open injury were recorded. One-hundred forty-one patients underwent screening at initial presentation, of whom 26 (24%) underwent early vascular exploration based on an abnormal physical examination. One-hundred five (91%) of the remaining 115 patients were available at a minimum followup of 6 months (mean, 19 ± 10 months). In total, 31 unique patients were excluded, including 10 patients (7%) who were lost to followup before 6 months. Among the 110 patients who met inclusion criteria, the mean age and SD was 37 ± 13 years, and the Injury Severity Score was 15 ± 9. There were 71 males (65%). Logistic regression was used to determine independent correlates of vascular injury. The vascular examination was reviewed for the presence of a palpable pulse in the dorsalis pedis artery, the presence of a palpable pulse in the posterior tibial artery, and whether the ABI in the dorsalis pedis was 0.9 or greater. Contingency tables were generated to assess the sensitivity, specificity, and accuracy of physical examination maneuvers. The physical examination was collectively regarded as "normal" when both pulses were palpable and the ABI was 0.9 or greater. The initial physical examination as just described was considered the diagnostic test being evaluated in this study; "positive" tests were evaluated by and confirmed at vascular surgery, and 6 months clinical followup without symptoms or progressive signs of vascular injury confirmed the absence of injury in the remainder of the patients. Contingency tables were generated again to assess the sensitivity, specificity, and accuracy of the combined physical examination., Results: Increased BMI (odds ratio [OR], 1.077; 95% CI, 1.008-1.155; p = 0.033) and open injuries (OR, 3.366; 95% CI, 1.008-11.420; p = 0.048) were associated with vascular injury. No single physical examination maneuver had a 100% sensitivity for ruling out vascular injury. A normal physical examination (palpable pulses and ABI ≥ 0.9) had 100% sensitivity for ruling out vascular injury., Conclusions: Increased BMI and the presence of open dislocation are associated with a greater risk for vascular injury after knee dislocation. The combination of a palpable dorsalis pedis and posterior tibial pulse combined with an ABI of 0.9 or greater was 100% sensitive for the detection of vascular injury based on clinical followup at 6 months., Level of Evidence: Level III, diagnostic study.

Though a relatively rare orthopedic injury, knee dislocation in the morbidly obese population has been increasingly reported in the literature. These injuries are often referred to as "ultralow-velocity knee dislocations" since they commonly occur after a seemingly trivial injury, such as a ground level fall. As a result, these injuries are often underappreciated and initially misdiagnosed. Even though these injuries are low-velocity, they should still be regarded as a high energy injury because of the large amount of mass contributing to the dislocating force. Knee dislocations in the morbidly obese are associated with a particularly high rate of neurovascular injury. A timely and accurate diagnosis is crucial to avoid serious limb-threatening complications, including the need for amputation. Therefore, evaluating physicians should maintain a high suspicion for a knee dislocation in any morbidly obese patient who presents with knee pain following a seemingly innocuous injury. Management of these injuries is controversial. Associated vascular injuries must be identified promptly and appropriately managed by a vascular surgery team. There is no consensus on the ideal orthopedic treatment of knee dislocations in the morbidly obese patient. Operative treatment can be fraught with complications, including a higher rate of neurovascular injury, increased surgical complications, and poor subjective patient outcome scores compared with nonobese patients sustaining a high-velocity knee dislocation. It is paramount that treating physicians are familiar with the unique challenges of treating knee dislocations in the morbidly obese patient when discussing risks and benefits of treatment options. This article presents a review of the existing literature on knee dislocations in the morbidly obese population, including diagnosis, management, and outcomes., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Fracture dislocation of the knee is a potentially limb-threatening injury with poor outcomes in the historical literature. This article describes a treatment algorithm for this injury that begins with making the correct diagnosis and continues through a staged treatment protocol. Results of 27 patients who were treated using this protocol are reported, demonstrating that good results can be obtained. There is a high incidence of complications associated with this injury, but patient outcomes are still good if they are recognized and treated appropriately., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

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.)

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., (Copyright 2015 by the American Academy of Orthopaedic Surgeons.)

This report describes a case of complete rupture of the peroneal nerve as a consequence of low velocity trauma. A 54-year-old physically fit patient suffered a complex trauma with complete nerve discontinuity as a result of knee joint distortion without external force. The initial medical findings were unremarkable, in particular neither the accident medical history nor the initial sensitivity impairment suggested the presence of serious knee damage; however, during clinical diagnostics a complex trauma with rupture of the peroneal nerve was found. Accordingly, an extensive revision with nerve suturing was carried out.

Knee dislocation with a common peroneal nerve injury is a serious problem. A case of multi-ligamentous knee injury with the unusual and interesting finding of a common peroneal nerve rupture incarcerated within the knee joint is presented. MRI and arthroscopic images are used to document this occurrence. To date, there are no published reports of a similar finding in the English orthopaedic literature. Level of evidence IV.

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.

Given the high incidence of vascular and neurologic injury associated with pediatric knee dislocations and displaced physeal injuries about the knee, a thorough understanding of the clinical and radiographic signs associated with these injuries, relevant anatomy, workup, reduction techniques, and surgical management is crucial. A higher incidence of these injuries in children is anticipated because of increased participation in high-energy activities that result in contact or collision during sports or recreation. Complications, such as vascular and nerve injuries and compartment syndrome, can be diagnosed early in the workup to prevent catastrophic outcomes. The clinical examination should include evaluation of the motor and sensory status of the limb, palpation of pulses, and measurement of ankle brachial indices. Radiographic examination should include plain radiography and supplemental advanced imaging, if indicated. Vascular imaging or expert consultation should be considered when the pulse or ankle brachial index is abnormal on clinical examination. Selection of nonsurgical or surgical treatment depends on the fracture pattern and stability., (Copyright 2015 by the American Academy of Orthopaedic Surgeons.)

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.