Mark A. Seeley

Magnetic resonance imaging of acute patellar dislocation in children: patterns of injury and risk factors for recurrence

Background: Acute patellar dislocation is a common traumatic condition of the knee seen in the active adolescent. The patterns of injury to the ligamentous and chondral surfaces following dislocation have not been well defined in the pediatric population. The purpose of this study was to characterize the patterns of medial patellofemoral ligament (MPFL), vastus medialis obliqus (VMO), and osteochondral injury on magnetic resonance imaging (MRI) following first-time acute lateral patellar dislocation in pediatric patients. Methods: Following approval by the Institutional Review Board, a radiology query was performed to identify all patients between the ages of 11 and 18 years who underwent MRI following an acute first-time patellar dislocation over a 10-year period. The presence and location of injury to the MPFL, VMO, and chondral surfaces were evaluated on MRI images. A retrospective review of the patient’s chart was conducted to confirm that clinical history was consistent with an acute patellar dislocation. Demographic data, including age at the time of injury, sex, knee affected, mechanism of injury, and recurrence of dislocation, were retrieved from the chart. The data were analyzed as a single cohort. Results: One hundred and eleven patients, including 56 males and 46 females with a mean age of 14.9 years (range, 11 to 18 y), were included. MRI demonstrated MPFL injury in 87 patients (78.4%). MPFL injury was present at an isolated patellar insertion in 34 patients (31%) and an isolated femoral insertion in 16 patients (14%). MPFL injury at more than one location was present in 37 patients (33%). VMO edema was present in 62 patients (56%), consistent with sprain or tear. Osteochondral fracture was identified in 38 knees (34%), with 25 from the medial patellar facet, 5 from the lateral femoral condyle, and 8 from both locations. Conclusions: Acute patellar dislocations remain a common injury in pediatric patients. The pattern of injury to the MPFL and VMO on MRI has not been described in a pediatric population. The triad of injury to the MPFL, VMO, and chondral surfaces should be recognized and understood, particularly when surgical reconstruction is necessary. Level of Evidence: Level III.

Osteochondral injury after acute patellar dislocation in children and adolescents.

Background: Acute patellar dislocation (APD) is a common injury in the pediatric patient population and may be associated with a spectrum of soft tissue and osteochondral injuries. This study describes the incidence of osteochondral fracture and associated injury patterns in a pediatric population after first-time APD and assesses functional outcomes after treatment. Methods: One hundred twenty-two patients, aged 11 to 18 years, who were evaluated after first-time APD over a 10-year period were identified, 46 of whom had confirmed osteochondral injury on magnetic resonance imaging (MRI). Demographic data, including knee affected, mechanism of injury, recurrent dislocation, operations performed, and condition at last follow-up, were retrieved from the medical record. Operative reports and MRI were used to characterize the location of osteochondral injury. The functional outcome of each patient with an osteochondral fracture was assessed using the Pedi-IKDC questionnaire. Results: Forty-six patients, mean age 14.6 years (range, 11 to 18 y), were included. Osteochondral fracture occurred at the patella in 35 patients (76%), the lateral femoral condyle in 11 patients (24%), and at both locations in 3 patients (6.5%). In 21 patients (44%), MRI confirmed osteochondral injury despite the plain radiograph interpretation as negative for fracture. Twenty-six patients (68%) subsequently underwent surgery after injury. Injury to the medial patellofemoral ligament was identified on MRI in 97.8% of patients (45/46). Fifteen patients (32.6%) underwent a concomitant medial repair at the time of surgery. Osteochondral injury to the distal femur on average had a lower International Knee Documentation Committee score than patellar injuries (72.3±18 vs. 91.1±10.2, P<0.003). Femoral osteochondral injury involving the weight-bearing surface (75.27±18.19) scored lower than non–weight-bearing surface injuries (93.22±7.47; P<0.001). Conclusions: The incidence of osteochondral injury associated with APD is high. Osteochondral fractures may initially go unrecognized on plain radiographs. Patients with weight-bearing lateral femoral condyle injuries had lower short-term functional scores, suggesting that outcomes depend on location of injury. Level of Evidence: Level IV, diagnostic and therapeutic study.

Change in Size of Hamstring Grafts During Preparation for ACL Reconstruction: Effect of Tension and Circumferential Compression on Graft Diameter.

BACKGROUND There is good consensus that anterior cruciate ligament (ACL) grafts should be pretensioned to remove creep prior to implantation, but the literature contains little information on the influence of graft preparation or circumferential compression on graft size. The purpose of this study was to investigate how the size of hamstring allografts changes as they are prepared for ACL reconstruction. We hypothesized that grafts decrease in diameter as they are prepared with both tension and circumferential compression. We also investigated the interrater reliability of graft diameter measurements during each step of graft preparation. METHODS Twenty pairs of fresh-frozen human hamstring tendons obtained from an allograft supplier were prepared in a standardized fashion for ACL reconstruction (suturing followed by longitudinal tensioning followed by circumferential compression followed by relaxation). Four blinded raters measured each graft in a sequential manner after each graft preparation step. Interrater reliability was assessed using the intraclass correlation coefficient ICC(2,1). The mean allograft diameter at each time point was calculated and compared across all time points using repeated-measures analysis of variance (ANOVA). RESULTS Subjecting the grafts to both tension and circumferential compression significantly decreased their mean diameter (to 7.38 mm compared with 8.28 mm at baseline; p = 0.044). Interrater reliability revealed almost perfect agreement at each measurement interval, with the ICC ranging from 0.933 to 0.961. CONCLUSIONS The average diameter of hamstring ACL grafts decreases by almost 1 mm after they are subjected to both tension and circumferential compression within a standard cylindrical sizing block. CLINICAL RELEVANCE Because ACL bone tunnels are drilled in 0.5-mm increments, preparing soft-tissue grafts with circumferential compression in addition to tension may allow creation of tunnels that are one to two incremental sizes smaller. This could permit less bone removal, which may be particularly applicable for certain reconstruction techniques such as pediatric, double-bundle, or revision ACL reconstruction, in which limited space is available for tunnel drilling.

Cost Savings From Utilization of an Ambulatory Surgery Center for Orthopaedic Day Surgery.

Introduction:Healthcare providers are increasingly searching for ways to provide cost-efficient, high-quality care. Previous studies on evaluating cost used estimated cost-to-charge ratios, which are inherently inaccurate. The purpose of this study was to quantify actual direct cost savings from performing pediatric orthopaedic sports day surgery at an ambulatory surgery center (ASC) compared with a university-based children’s hospital (UH). Methods:Custom-scripted accounting software was queried for line-item costs for a period of 3 fiscal years (fiscal year 2012 to fiscal year 2014) for eight day surgery procedures at both a UH and a hospital-owned ASC. Hospital-experienced direct costs were compared while controlling for surgeon, concomitant procedures, age, sex, and body mass index. Results:One thousand twenty-one procedures were analyzed. Using multiple linear regression analysis, direct cost savings at the ASC ranged from 17% to 43% for seven of eight procedures. Eighty percent of the cost savings was attributed to time (mean, 64 minutes/case; P < 0.001) and 20% was attributed to supply utilization (P < 0.001). Of the time savings in the operating room, 73% (mean, 47 minutes; P < 0.001) was attributed to the surgical factors whereas 27% (17 minutes; P < 0.001) was attributed to anesthesia factors. Conclusions:Performing day surgery at an ASC, compared with a UH, saves 17% to 43% from the hospital’s perspective, which was largely driven by surgical and anesthesia-related time expenditures in the operating room. Level of Evidence:Level II

Pediatric Lyme Arthritis of the Hip: The Great Imitator?

Background: Lyme arthritis (LA) of the hip can present similarly to septic arthritis (SA) and transient synovitis (TS). The primary purpose of this study was to determine clinical and laboratory parameters differentiating LA of the hip from SA or TS among children who had undergone hip aspiration during the evaluation of hip pain. Methods: This was a retrospective review of all patients who underwent hip aspiration for the evaluation of hip pain at a tertiary care children’s hospital in a Lyme endemic area. Clinical and laboratory data were reviewed and comparative analyses were performed between those diagnosed with LA, SA, and TS. Independent samples t test, ANOVA, and &khgr;2 test were used to compare clinical and laboratory variables as appropriate. Multivariable logistic regression was used to elucidate independent predictors of LA. Statistical significance was set at P<0.05. Results: Ninety-three hip aspirations (93 patients) were included in the final analysis. Seventeen patients were diagnosed with LA, 40 with SA, and 36 with TS. Multivariable logistic regression revealed febrile history (OR=16.3; 95% CI, 2.35-113.0) and increased peripheral white blood cell (WBC) count (OR=1.26; 95% CI, 1.01-1.58) to be significantly associated with increased odds of being diagnosed with SA versus LA. Increased erythrocyte sedimentation rate (ESR) was significantly associated with increased odds of being diagnosed with LA versus TS (OR=1.06; 95% CI, 1.02-1.10), whereas febrile history (OR=0.06; 95% CI, 0.01-0.49) and increased peripheral WBC count (OR=0.8; 95% CI, 0.65-0.98) were associated with decreased odds of LA. Conclusions: Children presenting in a Lyme endemic area with an isolated hip effusion are more likely to have LA versus SA if they have no history of fever and a decreased peripheral WBC count. Compared with TS, patients with LA are more likely to have an elevated ESR. This study adds to existing knowledge because there are few investigations examining isolated LA of the hip. Level of Evidence: Level III—retrospective case-control study.

Femoral deformity may be more predictive of hip range of motion than severity of acetabular disease in patients with acetabular dysplasia: An analysis of the ANCHOR cohort

Background: It is generally believed that acetabular dysplasia (AD) is associated with increased hip range of motion (ROM). The purpose of this study was to investigate the associations between dysplasia severity and hip ROM in a large multicenter cohort.Methods: A prospective registry of patients undergoing periacetabular osteotomy for symptomatic AD by 1 of 13 surgeons was used to analyze 1,051 patients (mean age, 26 ± 10 years). Multivariable linear regression modeling was used to investigate for associations between dysplasia severity (severe, <5°; moderate, 5° to 15°; mild, >15°), &agr; angle, and hip ROM.Results: When controlling for age, sex, body mass index, and &agr; angle, only internal (&agr; = 1.94; P = 0.005) and external (&agr; = −2.63; P < 0.001) rotation in extension were significantly different between groups with increasing dysplasia severity. Alpha angle was greater for those with severe AD compared with subjects with mild disease (60° ± 16° versus 57° ± 15°; P = 0.038). Alpha angle was also significantly correlated with rotational ROM parameters (internal and external rotation in flexion and extension) (Pearson r, range: −0.077 to −0.216; P < 0.05 for all), but not with linear motion.Conclusions: Internal rotation in extension was directly associated with dysplasia severity, whereas external rotation in extension was inversely associated. Furthermore, &agr; angle was greater with increasing dysplasia severity and predictive of rotational ROM parameters. Taken together, these data suggest that femoral-sided deformity, including &agr; angle and possibly femoral version, may be responsible for differences in ROM based on dysplasia severity.Level of Evidence: Level III, Prognostic

Anterior Knee Pain in Children and Adolescents: Overview and Management

Abstract Anterior knee pain (AKP) is a common presenting complaint for pediatricians and orthopaedic surgeons and is often seen in young athletes. AKP is multifactorial and has a broad differential diagnosis. The growth changes, biomechanics, and anatomy around the knee add to the complexity of diagnosis and treatment of AKP. Common causes of AKP include Osgood‐Schlatters disease, patellar tendinitis, and patellofemoral instability. In the diagnosis of AKP, it is important to rule out serious and morbid causes of pain, including infection and tumor. It is crucial to complete a detailed history and physical examination and obtain appropriate imaging studies. In general, the majority of patients will respond to nonoperative measures targeted to correct neuromuscular control and kinetic chain dysfunction.

Teaching the Basics: Development and Validation of a Distal Radius Reduction and Casting Model

BackgroundApproximately one-third of reduced pediatric distal radius fractures redisplace, resulting in further treatment. Two major modifiable risk factors for loss of reduction are reduction adequacy and cast quality. Closed reduction and immobilization of distal radius fractures is an Accreditation Council for Graduate Medical Education residency milestone. Teaching and assessing competency could be improved with a life-like simulation training tool.Questions/purposesOur goal was to develop and validate a realistic distal radius fracture reduction and casting simulator as determined by (1) a questionnaire regarding the “realism” of the model and (2) the quantitative assessments of reduction time, residual angulation, and displacement.MethodsA distal radius fracture model was created with radiopaque bony segments and articulating elbows and shoulders. Simulated periosteum and internal deforming forces required proper reduction and casting techniques to achieve and maintain reduction. The forces required were estimated through an iterative process through feedback from experienced clinicians. Embedded monofilaments allowed for quantitative assessment of residual displacement and angulation through the use of fluoroscopy. Subjects were asked to perform closed reduction and apply a long arm fiberglass cast. Primary performance variables assessed included reduction time, residual angulation, and displacement. Secondary performance variables consisted of number of fluoroscopic images, casting time, and cast index (defined as the ratio of the internal width of the forearm cast in the sagittal plane to the internal width in the coronal plane at the fracture site). Subject grading was performed by two blinded reviewers. Interrater reliability was nearly perfect across all measurements (intraclass correlation coefficient range, 0.94–0.99), thus disagreements in measurements were handled by averaging the assessed values. After completion the participants answered a Likert-based questionnaire regarding the realism of simulation. Eighteen participants consented to participate in the study (eight attending pediatric orthopaedic surgeons, six junior residents, four senior residents). The performances of junior residents (Postgraduate Year [PGY] 1–2), senior residents (PGY 3–5), and attending surgeons were compared using one-way ANOVA with Tukey’s-adjusted pairwise comparisons.ResultsThe majority of participants (15 of 18) felt that the model looked, felt, and moved like a human forearm. All participants strongly agreed that the model taught the basic steps of fracture reduction and should be implemented in orthopaedic training. Attending surgeons reduced fractures in less time than junior residents (60 ± 27 seconds versus 460 ± 62 seconds; mean difference, 400 seconds; 95% CI, 335–465 seconds; p < 0.001). Residual angulation was greater for junior residents when compared with attending surgeons on AP (7° ± 5° versus 0.7° ± 0.9°; mean difference, 6.3°; 95% CI, 3°–11°; p = 0.003) and lateral (27° ± 7° versus 7° ± 5°; mean difference, 20°; 95% CI, 13°–27°; p = 0.001) radiographs. Similarly, residual displacement was greater for junior residents than either senior residents (mean difference, 16 mm; 95% CI, 2–34 mm; p = 0.05) or attending surgeons (mean difference, 15 mm; 95% CI, 3–27 mm; p = 0.02) on lateral images. There were no differences identified in secondary performance variables (number of fluoroscopic images, casting time, and cast index) between groups.ConclusionsThis is the first distal radius fracture reduction model to incorporate an elbow and shoulder and allow quantitative assessment of the fracture reduction. This simulator may be useful in an orthopaedic resident training program to help them reach a defined minimum level of competency. This simulator also could easily be integrated in other accreditation and training programs, including emergency medicine.Level of EvidenceLevel II, therapeutic study.

Subtrochanteric Femur Fractures in Children

Pediatric subtrochanteric femur fractures are a challenging subset of fractures to treat, with a relative paucity of literature-based evidence to support specific algorithmic approaches. These fractures are rare, and there is no clear consensus among authors on the definition of a subtrochanteric femur fracture in children. Patient age, weight, femoral canal size, fracture stability, associated injuries, and surgeon experience should all be considered when determining the best treatment option. Infants 0–6 months of age are well treated with a Pavlik harness. Children 6 months to 5 years of age should be treated with a hip spica cast, although internal fixation is a viable alternative if the fracture is unstable. Flexible intramedullary nails, open plating, and submuscular plating are all successful treatment options in children 5–11 years of age, depending on the fracture pattern. Finally, children aged 11 years to skeletal maturity are well treated with rigid intramedullary nailing using a lateral trochanteric entry site. While these overall principles largely mirror trends currently applied for treatment of femoral shaft fractures in children, subtrochanteric fractures are frequently more prone toward displacement, due to the strong, divergent pull of muscular attachments in the peritrochanteric region. Therefore, consideration should be given toward selection of age-based treatment approaches more likely to ensure stability. All treatment methods have associated complications, and these should be discussed with the patient and family during the informed consent process.

Hip Vascularity: A Review of the Anatomy and Clinical Implications.

Throughout development, the vascular supply to the proximal femur and acetabulum undergoes a series of changes during which it is susceptible to injury. Before age 3 months, the ligamentum teres and lateral epiphyseal arteries are the dominant supply to the developing head. The dominant supply shifts to the lateral epiphyseal vessels by age 18 months. The distinct metaphyseal and epiphyseal circulations of the adult proximal femur form in adolescence when an increasingly rich metaphyseal circulation supplies the subphyseal region, terminating at the physeal plate. The acetabular blood supply derives from two independent systems, with the dominance of each changing throughout maturity. Most descriptions of the vascular contributions to the proximal femur and acetabulum have been gross anatomic and histologic studies. Advanced imaging studies (eg, CT angiography, perfusion MRI) have added to our understanding of the vascular anatomy of the proximal femur and acetabulum, its changes throughout development, and its clinical implications.