The changing demographics of knee dislocation: a retrospective database review.

BACKGROUND: Knee dislocations are uncommon but devastating orthopaedic injuries. Little is known about their frequency and the types of patients who are affected. QUESTIONS/PURPOSES: Using a large national insurance database, we determined (1) the incidence of knee dislocation in patients with orthopaedic injuries and examined the incidence as a function of (2) year of diagnosis, (3) dislocation type (open versus closed, direction), and (4) patient demographic factors (sex, age). METHODS: We searched the PearlDiver database, a national database of private insurance records consisting of 11 million patients with orthopaedic diagnoses, using diagnosis (ICD-9-CM) codes for knee dislocation between the years 2004 and 2009. The PearlDiver database does not include Medicare, Medicaid, or uninsured patients. Patients were stratified by age, sex, and year of diagnosis. Incidence was defined as the number of dislocation events per 100 patient-years. RESULTS: We identified 8050 dislocations, representing an incidence of 0.072 events per 100 patient-years between 2004 and 2009. Annual dislocation incidence did not increase during the 6-year study period. Of the 8050 dislocations, 1333 (17%) were open and 6717 (83%) were closed, representing an incidence of 0.060 per 100 for closed dislocations and 0.012 per 100 for open dislocations. The most common direction of dislocation was unspecified or other (65%), followed by anterior (13%), lateral (11%), posterior (6%), and medial (5%). Of the patients sustaining dislocations, 4172 (52%) were female and 3878 (48%) were male. Males displayed an increased risk of knee dislocation compared to females (odds ratio = 1.09). The mean patient age was 35 years, and patient age was inversely correlated to the incidence of knee dislocation (10-year odds ratio = 0.77). CONCLUSIONS: Our data suggest that knee dislocation might represent a significantly larger burden among orthopaedic injuries than previously thought. The finding that males and females have a nearly equal risk of knee dislocation enhances the diagnosing physician's clinical suspicion of this injury. Future large prospective studies analyzing the various causes of knee dislocation could provide insight into the changing demographics of this injury. LEVEL OF EVIDENCE: Level IV, prognostic study. See Instructions for Authors for a complete description of levels of evidence.

Vascular and nerve injury after knee dislocation: a systematic review.

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.

Combined endoscopic and transoral resection of a high-staged juvenile nasopharyngeal angiofibroma: A pictorial essay.

Juvenile nasopharyngeal angiofibromas (JNAs) are highly vascular and benign tumors that can expand into the skull base. Delay of treatment can result in intracranial invasion, requiring extensive open approaches such as a facial translocation, maxillary swing, or an orbitozygomatic craniotomy. We describe a single-stage, combined endoscopic and transoral approach on a 14-year-old male with extensive high-stage dumbbell-shaped JNA involving the infratemporal fossa, orbit, buccal space, and intracranial extension into Meckel's cave. Successful resection of the tumor and good postoperative outcome was achieved. A transoral approach allowed for greater access to the infratemporal fossa, where endonasal resection was not possible, allowing for improved visualization, greater traction, and dissection. In select highly staged JNAs with significant lateral extension and intracranial involvement, successful and complete resection may be accomplished with this combined approach. Utilization of this approach avoids the morbidity of more invasive open approaches.

In vivo evaluation of electrospun polycaprolactone graft for anterior cruciate ligament engineering.

The anterior cruciate ligament (ACL) is critical for the structural stability of the knee and its injury often requires surgical intervention. Because current reconstruction methods using autograft or allograft tissue suffer from donor-site morbidity and limited supply, there has been emerging interest in the use of bioengineered materials as a platform for ligament reconstruction. Here, we report the use of electrospun polycaprolactone (PCL) scaffolds as a candidate platform for ACL reconstruction in an in vivo rodent model. Electrospun PCL was fabricated and laser cut to facilitate induction of cells and collagen deposition and used to reconstruct the rat ACL. Histological analysis at 2, 6, and 12 weeks postimplantation revealed biological integration, minimal immune response, and the gradual infiltration of collagen in both the bone tunnel and intra-articular regions of the scaffold. Biomechanical testing demonstrated that the PCL graft failure load and stiffness at 12 weeks postimplantation (13.27±4.20N, 15.98±5.03 N/mm) increased compared to time zero testing (3.95±0.33N, 1.95±0.35 N/mm). Taken together, these results suggest that electrospun PCL serves as a biocompatible graft for ACL reconstruction with the capacity to facilitate collagen deposition.