Association of Relative Skeletal Immaturity of the Triradiate Cartilage with Increased Proximal Femoral Deformity in Prophylactic Fixation for Slipped Capital Femoral Epiphysis: A Radiographic Study.

INTRODUCTION: The purpose of this study was to describe proximal femoral deformity after contralateral hip prophylactic fixation of slipped capital femoral epiphysis (SCFE) in patients and the association of relative skeletal immaturity with this deformity. METHODS: A retrospective review of patients presenting with a SCFE was conducted from 2009 to 2015. Inclusion criteria were (1) radiographic evidence of a unilateral SCFE treated with in situ fixation, (2) contralateral prophylactic fixation of an unslipped hip, and (3) at least 3 years of follow-up. Measurements were made on radiographs and included greater trochanter height relative to the center of the femoral head, femoral head-neck offset, and femoral neck length. Skeletal maturity was evaluated by assessing the status of the proximal femoral physis and triradiate cartilage (TRC) of the hip, in addition to the length of time to closure of these physes. Values were compared from initial presentation to final follow-up. Statistical analysis included descriptive statistics and linear regression. RESULTS: Twenty-seven patients were included. Bivariable linear regression demonstrated that an increased relative trochanteric overgrowth was associated with TRC width (ß = 3.048, R = 0.585, P = 0.001) and an open TRC (ß = -11.400, R = 0.227, P = 0.012). Time to proximal femoral physis closure (ß = 1.963, R = 0.444, P = 0.020) and TRC closure (ß = 1.983, R = 0.486, P = 0.010) were predictive of increased deformity. In addition, multivariable elimination linear regression demonstrated that TRC width (ß = 3.048, R = 0.585, P = 0.001) was predictive of an increased relative trochanteric overgrowth. DISCUSSION: Patients with an open TRC and increased TRC width are associated with increased relative trochanteric overgrowth when undergoing prophylactic fixation for a unilateral SCFE. Increased caution should be exercised when considering contralateral hip prophylactic fixation in skeletally immature patients presenting with a unilateral SCFE. LEVEL OF EVIDENCE: Level IV, case series.

Hardware Impingement Is Associated With Shorter Screw Length in Patients Treated With In Situ Screw Fixation for Slipped Capital Femoral Epiphysis: An In Vivo Arthroscopic Evaluation.

Purpose: To determine the incidence of screw impingement on dynamic exam during hip arthroscopy in patients undergoing treatment for femoroacetabular impingement after previous slipped capital femoral epiphysis fixation and to evaluate screw characteristics with hardware impingement. Methods: A retrospective review from 2008 to 2020 was performed of slipped capital femoral epiphysis (SCFE) patients that underwent arthroscopy for symptoms of hip impingement. Patients underwent a dynamic exam under direct arthroscopic visualization to assess for sources of impingement, including bony anatomy and fixation hardware. Slip angle was calculated on lateral radiographs prior to arthroscopy, and screw length was noted in the initial operative reports at treatment of SCFE and reported in millimeters. Normality of data was assessed using Shapiro-Wilk tests, with statistical analysis performed using independent sample t-tests, Mann-Whitney U-nonparametric tests, and multivariable logistic regression. An alpha level of <0.05 was used to indicate statistical significance. Results: Thirty-nine hips were included, with 13 (33.3%) having screw impingement on dynamic exam. Slip angle was found to be increased in the screw impingement group (42.4° vs 35.5°; P = .11). Screw length was noted to be significantly shorter in the screw impingement group (53.1 vs 61.6 mm; P = .021). The presence of screw impingement was found to be associated with shorter screw length (ß = -0.172, R 2 = 0.329; P = .036). Conclusions: Shorter screws (55 mm or less) are at greater risk of causing hardware hip impingement after in situ SCFE fixation. When considering hip arthroscopy for the treatment of femoroacetabular impingement in patients with a previous SCFE, hardware impingement and subsequent hardware removal should be considered in hips with shorter screws and in hips that show objective hardware impingement on dynamic exam. Level of Evidence: Level IV, therapeutic case series.

The National Interscholastic Cycling Association Mountain Biking Injury Surveillance System: 40,000 Student-Athlete-Years of Data.

ABSTRACT: A web-based injury surveillance system was implemented through a collaboration between University of Utah researchers and the National Interscholastic Cycling Association (NICA) to better understand injury characteristics in mountain biking. Data were collected from NICA leagues during the 2018 and 2019 seasons. Injuries were tracked in 41,327 student-athlete-years, identifying 1750 unique injuries during 1155 injury events. Rider-dependent and rider-independent variables were analyzed. The most commonly reported injuries were concussion (23.6%), injuries to the wrist/hand (22.3%), and shoulder (15.6%). Half of all injury events occurred on downhills. Men and women reported similar yet significantly different injury rates (2.69% and 3.21%, respectively; P = 0.009). Women sustained more lower-limb injuries (37.8% vs 28.3%; P = 0.003). Nearly 50% of crashes resulted in an emergency room visit. Youth mountain bike racing is a rapidly growing sport. Acute traumatic injuries are common. Injury surveillance system data are now being used to inform injury prevention strategies and direct future research.

Growth-friendly Spinal Instrumentation in Marfan Syndrome Achieves Sustained Gains in Thoracic Height Amidst High Rates of Implant Failure.

BACKGROUND: There are few reports on the surgical management of early-onset scoliosis (EOS) associated with Marfan syndrome (MFS). Affected patients tend to have more rapid curve progression than those with idiopathic EOS, and their course is further complicated by medical comorbidities. As surgical techniques and implants for growing spines become more widely applied, this study seeks to better delineate the safety and efficacy of growth-friendly spinal instrumentation in treating this population. METHODS: A prospective registry of children treated for EOS was queried for MFS patients treated between 1996 and 2016. Forty-two patients underwent rib-based or spine-based growing instrumentation and were assessed on preoperative, surgical, and postoperative clinical and radiographic parameters including complications and reoperations. Subgroup analysis was performed based on spine-based versus rib-based fixation. RESULTS: Patients underwent their index surgery at a mean age of 5.5 years, when the major coronal curve and kyphosis measured 77 and 50 degrees, respectively. Over half were treated with traditional growing rods. Patients underwent 7.2 total surgical procedures-4.7 lengthening and 1.9 revision surgeries not including conversion to fusion-over a follow-up of 6.5 (±4.1) years. Radiographic correction was greatest at index surgery but maintained over time, with a final thoracic height measuring 23.8 cm. Patients experienced a mean of 2.6 complications over the course of the study period; however, a small group of 6 patients experienced ≥6 complications while over half of patients experienced 0 or 1. Implant failures represented 42% of all complications with infection and pulmonary complications following. CONCLUSIONS: This is the largest report on patients with EOS and MFS. All subtypes of growth-friendly constructs reduced curve progression in this cohort, but complications and reoperations were nearly universal; patients were particularly plagued by implant failure and migration. Further collaborations are needed to enhance understanding of optimal timing and fixation constructs for those with MFS and other connective tissue diseases.

The NICA injury surveillance system: Design, methodology and preliminary data of a prospective, longitudinal study of injuries in youth cross country mountain bike racing.

OBJECTIVES: To describe the design and implementation of an injury surveillance system for youth mountain bike racing in the United States, and to report preliminary first-year results. DESIGN: Descriptive sports injury epidemiology study. METHODS: After two and a half years of development and extensive beta-testing, an electronic injury surveillance system went live in January, 2018. An automated email is sent to a Designated Reporter on each team, with links to the injury reporting form. Data collected include demographic information, injured body part, injury diagnosis, trail conditions and other factors associated with injury occurrence. RESULTS: 837 unique injuries were reported in 554 injury events among 18,576 student-athletes. The overall injury event proportion was 3.0%. The most common injury among student-athletes was concussion/possible concussion (22.2%), followed by injuries to the wrist and hand (19.0%). Among 8,738 coaches, there were 134 unique injuries reported that occurred in 68 injury events, resulting in an overall injury event proportion of 0.8%. The shoulder (38.2%) was the most commonly injured body part among coaches. Injuries among coaches tended to more frequently result in fractures, dislocations and hospital admission compared with injuries among student-athletes. Among student-athletes, female riders sustained lower limb injuries more than male riders (34.0% vs. 20.7%, p<0.001). CONCLUSIONS: A nationwide injury surveillance system for youth mountain bike racing was successfully implemented in the United States. Overall injury event proportions were relatively low, but many injury events resulted in concussions/possible concussions, fractures, dislocations and 4 weeks or longer of time loss from riding.

Cozen's deformity: resolved by guided growth.

Proximal tibial metaphyseal fractures in children can lead to progressive and symptomatic tibial valgus. Corrective osteotomy has been abandoned, due to frequent complications, including recurrent valgus deformity. While spontaneous remodelling has been reported, this is not predictable. For children with persistent deformities, we have resorted to guided growth of the tibia. We present 19 patients who were successfully treated with guided growth, tethering the proximal medial physis. There were ten boys and nine girls, ranging in age from two to 13.6 years at the time of intervention. The mean follow-up from injury was 7.3 years. We documented the intermalleolar distance, mechanical axis deviation (by zone), medial proximal tibial angle (MPTA), and leg length discrepancy. Removal of the plate, or more recently, the metaphyseal screw, was undertaken upon normalization of the mechanical axis. Including the four patients who have undergone repeat tethering for recurrent valgus (one patient-twice), we are effectively reviewing 24 Cozen's phenomena, making this the largest series reported in the literature. Correction of the mechanical axis and the proximal medial tibial angle was achieved in all but one patient. Limb length inequality at follow-up ranged from 0.1 to 1.5 cm, with a mean of 0.5 cm. There have been five recurrences in four patients to date; four corrected with repeat tethering and one is pending. Two patients developed significant over correction because of parental failure to pursue timely follow-up. Both have corrected to neutral with lateral tibial physeal tethering. Ten patients have attained skeletal maturity and required no further treatment. The remaining nine patients will be followed until maturity. Guided growth is an excellent choice for the management of post-traumatic tibial valgus. Our rationale for restricting medial overgrowth is twofold: (1) to restore the MPTA and (2) to reduce the length discrepancy due to tibial overgrowth caused by the fracture. Recognizing the potential for recurrent deformity following implant removal, our standard practice now includes removal of just the metaphyseal screw and subsequent reinsertion, in the event of rebound valgus deformity.Level of evidence Therapeutic IV, retrospective series/no control cohort.

Rib-based Distraction Surgery Maintains Total Spine Growth.

BACKGROUND: For children undergoing treatment of early onset scoliosis (EOS) using spine-based distraction, recently published research would suggest that total spine length (T1-S1) achieved after the initial lengthening procedure decreases with each subsequent lengthening. Our purpose was to evaluate the effect of rib-based distraction on spine growth in children with EOS. METHODS: This was a retrospective multi-center review of 35 patients treated with rib-based distraction (minimum 5 y follow-up). Radiographs were analyzed at initial implantation and just before each subsequent lengthening. The primary outcome was T1-S1 height, which was also analyzed as: Change in T1-S1 height per lengthening procedure, percent of expected age-based T1-S1 growth per lengthening time interval, percent increase in T1-S1 height as compared with postimplantation total spine height, and percent of expected T1-S1 growth based upon patient age at time of lengthening procedure. RESULTS: Thirty-five patients with a mean age of 2.6 years at initial surgery were studied. Diagnoses included congenital (n=18), syndromic (n=7), idiopathic (n=5), and neuromuscular (n=5). Major Cobb angle was 63.5 degrees and kyphosis was 40.5 degree. Four postoperative time periods were compared: L1 (preoperative first lengthening surgery), L2-L5 (preoperative second lengthening to preoperative fifth lengthening), L6-L10 (preoperative sixth lengthening to preoperative 10th lengthening), L11-L15 (preoperative 11th lengthening to preoperative 15th lengthening). Cobb angle stayed relatively constant for each lengthening period while maximum kyphosis increased. Total spine height was 19.9 cm pre-implantation, 22.1 cm postimplantation, and 28.0 cm by the 15th lengthening (P<0.05). Percent expected T1-S1 growth per lengthening was 62% for L2-L5, 95% for L6-L10, and 52% for L11-L15. As compared with postimplantation spine height, over the course of 15 lengthening procedures, a further 27% increase in spine height was observed. When lengthening procedures were performed when children were under age 5 years, 82% of expected growth was observed; between ages 6 and 10 years, 76% of expected growth was observed; and beyond age 10 years, 14% of expected growth was observed. CONCLUSIONS: Patients treated with rib-based distraction surgery had an increase in total spine height from 20 cm preimplantation to 28 cm by the 15th lengthening. They maintained greater than 75% of expected age-matched spine growth until age 10 years and lengthening procedures did not appear to follow a law of diminishing returns. Rib-based distraction is an effective means of maintaining spine growth which is likely beneficial for pulmonary development as compared with the natural history of EOS. LEVEL OF EVIDENCE: Level IV-Therapeutic study, case series.

Success of torsional correction surgery after failed surgeries for patellofemoral pain and instability.

Torsional deformities of the femur and/or tibia often go unrecognized in adolescents and adults who present with anterior knee pain, and patellar maltracking or instability. While open and arthroscopic surgical techniques have evolved to address these problems, unrecognized torsion may compromise the outcomes of these procedures. We collected a group of 16 consecutive patients (23 knees), with mean age of 17, who had undergone knee surgery before torsion was recognized and subsequently treated by means of rotational osteotomy of the tibia and/or femur. By follow-up questionnaire, we sought to determine the role of rotational correction at mean 59-month follow-up. We reasoned that, by correcting torsional alignment, we might be able to optimize long-term outcomes and avert repeated knee surgery. Knee pain was significantly improved after torsional treatment (mean 8.6 pre-op vs. 3.3 post-op, p < 0.001), while 70 % of patients did have some continued knee pain postoperatively. Only 43 % of patients had continued patellar instability, and 57 % could trust their knee after surgery. Activity level remained the same or increased in 78 % of patients after torsional treatment. Excluding planned rod removal, subsequent knee surgery for continued anterior knee pain was undertaken on only 3 knees in 2 patients. We believe that malrotation of the lower limb not only raises the propensity for anterior knee symptoms, but is also a under-recognized etiology in the failure of surgeries for anterior knee pain and patellar instability. Addressing rotational abnormalities in the index surgery yields better clinical outcomes than osteotomies performed after other prior knee surgeries.

A randomized prospective evaluation of 3 techniques of postoperative pain management after posterior spinal instrumentation and fusion.

STUDY DESIGN: Randomized prospective trial. OBJECTIVE: To compare the efficacy of intravenous analgesia with single and dual continuous epidural analgesia (CEA) in patients with adolescent idiopathic scoliosis (AIS) undergoing posterior spinal fusion and instrumentation (PSIF). SUMMARY OF BACKGROUND DATA: Pain management after posterior spinal fusion (PSF) for patients with AIS is challenging. Although intravenous patient-controlled analgesia (PCA) is used most commonly, CEA has been found to be safe and effective. Recently, the use of 2 epidural catheters has been thought to be more effective than a single catheter, although the efficacy of using 2 catheters has not been directly compared with a single catheter. METHODS: Sixty-six patients with AIS were randomized into 3 groups prior to PSF; PCA, single CEA, and double CEA. Postoperative pain scores as well as side effects, complications, and use of breakthrough medication were collected. Recovery times were also recorded, including hospitalization, times to first bowel movement, and days to walk and climb stairs. Four patients were withdrawn due to the inability to maintain the pain management protocol. RESULTS: Pain intensity was most effectively controlled with a double CEA when compared with PCA (P < 0.05) and a single CEA (P < 0.05). Pain control was equivalent in both the PCA and single CEA groups (P = 0.21). The pain control method with the fewest side effects trended toward the single CEA, with an average of 2.55 side effects per patient. The majority of the side effects included pruritis, constipation, and nausea. Late onset neurological events were absent in all patients. CONCLUSION: These data document that the double CEA most effectively controls postoperative pain after surgery for AIS. The single CEA trended toward having the fewest side effects when compared with the other techniques. On the basis these findings, we now routinely use the double CEA technique for all patients having surgery for AIS.

The location of the medial humeral epicondyle in children: position based on common radiographic landmarks.

BACKGROUND: Medial humeral epicondyle fracture displacement in children is difficult to quantify, as current methods suffer from significant intraobserver and interobserver variability. The aim of this study was to create a systematic approach to determine medial epicondyle fracture displacement based upon easily identifiable radiographic landmarks of the elbow. METHODS: In this anatomic descriptive study, we evaluated 171 anteroposterior (AP) and lateral radiographs from children (4 to 15 years old) with a normal distal humerus. On the AP radiograph, the center of the medial epicondyle was compared with a line based upon the inferior olecranon fossa. On the lateral radiograph, the center of the medial epicondyle was compared with the posterior humeral line. RESULTS: On the AP radiograph, the average location of the center of the medial epicondyle was 0.5 mm inferior to the olecranon line (SD, 2.0 mm). On the lateral radiograph, the average location of the center of the medial epicondyle was 1.2 mm anterior to the posterior humeral line (SD, 1.2 mm). CONCLUSIONS: Our findings demonstrated a consistent radiographic position of the medial humeral epicondyle with little variation throughout skeletal maturation. CLINICAL RELEVANCE: This study may be helpful in assessing fracture displacement in pediatric medial epicondyle fractures.

Lower Extremity Assessment Project (LEAP)--the best available evidence on limb-threatening lower extremity trauma.

Lower Extremity Assessment Project (LEAP) study set out to answer many of the questions surrounding the decision of whether to amputate or salvage limbs in the setting of severe lower extremity trauma. A National Institutes of Health-funded, multicenter, prospective observational study, the LEAP study represented a milestone in orthopedic trauma research, and perhaps in orthopedics. The LEAP study attempted to define the characteristics of the individuals who sustained these injuries, the characteristics of their environment, the variables of the physical aspects of their injury, the secondary medical and mental conditions that arose from their injury and treatment, their ultimate functional status, and their general health. In the realm of evidence-based medicine, the LEAP studies provided a wealth of data, but still failed to completely determine treatment at the onset of severe lower extremity trauma.

Involvement of the spine in patients with multiple hereditary exostoses.

BACKGROUND: Extension of a vertebral exostosis into the spinal canal is rare, but many isolated cases have been reported in the literature. Three existing patients with multiple hereditary exostoses at our institution had development of neurologic findings and were found to have exostoses in the spinal canal. These findings led us to perform magnetic resonance imaging or computed tomographic scans for the remaining patients with multiple hereditary exostoses at our institution. METHODS: Forty-four patients at our institution (including twenty-six male patients and eighteen female patients) had multiple hereditary exostoses. Forty-three patients were evaluated with magnetic resonance imaging and one was evaluated with computed tomography to look for spinal column involvement. RESULTS: Thirty (68%) of the forty-four patients had exostoses arising from the spinal column, and twelve (27%) had lesions encroaching into the spinal canal. Thirty-six of the forty-four patients also had plain radiographs, but only six had radiographs that accurately identified the lesions and another six had radiographs that mistakenly identified lesions that were not confirmed with magnetic resonance imaging or computed tomography. Patients with lesions inside the spinal canal were typically asymptomatic and neurologically normal, with radiographs that did not demonstrate the lesion. Compared with female patients, male patients were more likely to have spinal lesions and more likely to have lesions encroaching into the spinal canal (p = 0.014). CONCLUSIONS: The risk that a patient with multiple hereditary exostoses has a lesion within the spinal canal is much higher than previously suspected (27%). Because the potential exists for serious neurologic injury to occur, we have begun to use magnetic resonance imaging to screen all patients who have multiple hereditary exostoses at least once during the growing years.

Incidence and morphology of the posteromedial fragment in bicondylar tibial plateau fractures.

OBJECTIVES: Bicondylar tibial plateau fractures featuring extensive articular involvement have a record of mixed clinical results. Recent discussion has focused on the significance of a posteromedial articular fragment in bicondylar injuries. This fragment has often gone unrecognized or has not been addressed. The posteromedial fragment is defined as any posteriorly based articular fracture of the medial plateau with the fracture line exiting the medial cortex. This study is designed to produce a detailed description of the incidence, size, and shape of this fracture, as this may be helpful in driving the choice of both approach and fixation for these injuries. Furthermore, a better understanding of this fracture's morphology may lead to a better ability to model the biomechanical reliability of laterally based locking fixation in securing the reduction of this fracture fragment. DESIGN: Retrospective study of patient records and computed tomography scans. SETTING: Level I university regional trauma center. PATIENTS: All patients treated for bicondylar tibial plateau fracture from January 1, 2002, through August 31, 2007. RESULTS: One hundred forty-eight patients were identified in the 5.5-year period, and 111 had complete computed tomography records (75%). Of 111 bicondylar tibial plateau fractures analyzed, this fragment occurred in 65 cases (59% incidence) and on average accounted for 25% of the total tibial plateau joint surface. There was greater than 5 mm of articular displacement in 55% of cases. The posteromedial fragment exhibits a vertical fracture pattern (average sagittal angle 73 degrees), suggestive of shear instability and vertical displacement. CONCLUSIONS: Given the high frequency, significant portion of the joint involved, significant displacement, and pattern suggestive of instability, surgeons need to be cognizant of this pattern and may need to consider directly reducing and fixating this fragment through a posteromedially based approach. Overall morphologic findings of the posteromedial fragment are highly consistent with other recent data on this pattern. This information may also be useful in modeling fracture fixation for future study.

Guided growth for fixed knee flexion deformity.

BACKGROUND: Fixed knee flexion deformity (FKFD) is an insidious problem that may complicate the management of patients with neuromuscular compromise due to cerebral palsy, spina bifida, arthrogryposis, and other conditions. The energy costs associated with crouch gait may become prohibitive and, with the inexorable progression of fixed knee flexion, secondary pain may ensue as a result of fragmentation of the patella and/or tibial tubercle. Concomitant or compensatory flexion deformity of the hips and lumbar lordosis may develop, along with "pseudo equinus" of the ankles. Recommended treatments for FKFD have included bracing; physical therapy; and, in recalcitrant cases, distal femoral osteotomy, posterior release, or frame distraction. However, these latter modalities are fraught with potential complications including neurovascular damage, loss of fixation, undercorrection malunion, fracture, and recurrent deformity. Considering that FKFD is often bilateral, the complication risks for a given patient are doubled. In a previous study, the senior author reported successful hemiepiphysiodesis of the distal anterior femur using staples. However, further experience has demonstrated some of the limitations of stapling including relatively slow correction and occasional hardware migration. This led to the development of a more versatile and reliable solution using a pair of anterior tension band plates. METHODS: In this retrospective clinical study, we are reporting this new technique of promoting gradual correction through guided growth of the distal femur, using a pair of anterior 8-plates. The correction is accomplished simultaneously and bilaterally, without immobilization, and may be combined with other operative procedures as indicated. We reviewed the charts, radiographs in a group of patients treated accordingly. RESULTS: In this group of 18 patients with 29 deformities, we noted correction averaging 1.3 degrees (range, 0.0 [1 patient]-4.8 degrees), with minimal complications. No inadvertent coronal plane deformities were created. Upon full correction, the plates were removed so as to avoid recurvatum. CONCLUSION: As an alternative to posterior capsulotomy or supracondylar extension osteotomy, we have found that guided growth is an effective and safe method of gradually correcting FKFD in growing children and adolescents. LEVEL OF EVIDENCE: 4 (retrospective clinical series).

Guided growth for pathological physes: radiographic improvement during realignment.

BACKGROUND: Children with rickets are prone to having deformities of the lower extremities that are bilateral and often symmetrical. Although initially attributed to pathological or "sick" physes, the deformities are eventually seen in the metaphyses and diaphyses of the long bones; if left untreated, they may result in bone pain and stress fractures. The orthopaedists' role in managing these children is to correct and maintain alignment. Alternatively, we have exploited the use of hemiepiphysiodesis or guided growth, using staples or, more recently, the 8-plate (Orthofix, Verona, Italy). While gradually normalizing the mechanical axis, we have noted improvement in the appearance and width of all of the ipsilateral physes, not only at the knee but at the hip and ankle as well. This report summarizes our observations of the effects on the pathological physes in a group of patients with rickets who were preferentially treated with guided growth, often starting at a young age. METHOD: This retrospective review approved by an institutional review board included 14 children with rickets, including 10 treated with staples and 4 with 8-plates, who collectively underwent a total of 68 hemiepiphysiodeses (guided growth) and 35 osteotomies. Each was under appropriate medical management during the entire course of treatment, before and after surgery. We measured the mechanical axis deviation and anatomic angles of the femur and proximal tibia, noting the width and appearance of their physes at the hips, knees, and ankles preoperatively and upon correction of the axis. RESULTS: Of the 10 stapled patients, we noted 24 (45%) of 53 migrations and 41% rebound deformity. Four patients with 15 deformities that corrected with 8-plates experienced no hardware migration; for them, it is too early to comment on rebound deformity. While gradually correcting the mechanical axis, we have noted improvement in the appearance and width, not only of the pan-genu physes but also of remote physes at the hip and ankle. We suspect that the improved quality of the physes reflects not only the normalization of the mechanical axis but also the corresponding resolution of the waddling (varus) or circumduction (valgus) gait pattern. CONCLUSION: We recommend early intervention, via guided growth, to restore and preserve a neutral axis so that the child can enjoy a normal lifestyle while maximizing the growth potential of his or her physes, not only of the knees but the hips and ankles as well. We believe that by correcting and maintaining alignment, secondary bony deformities may be ameliorated and osteotomies for angular correction deferred if not avoided altogether. LEVEL OF EVIDENCE: IV (retrospective clinical series).

Biomechanical analysis of bicondylar tibial plateau fixation: how does lateral locking plate fixation compare to dual plate fixation?

OBJECTIVES: This study is designed to test the comparative strength of lateral-only locked plating to medial and lateral nonlocked plating in a cadaveric model of a bicondylar proximal tibial plateau fracture. METHODS: Ten matched pairs of human cadaveric proximal tibia specimens were used for biomechanical testing. Cyclic loading using a materials testing device simulated initial range of motion and load bearing following surgical repair. Subsidence of the medial and the lateral condyles was measured following 10,000 cycles from 100N to 1,000N; the maximum load to failure on the medial condyle for both plate constructs was also measured. RESULTS: On the lateral side, dual plating (DP) allowed an average of 0.68 +/- 0.14 mm of subsidence, compared with 1.03 +/- 0.27 mm for the fixed-angle plate (FAP) (P = 0.077). On the medial side, DP allowed an average of 0.78 +/- 0.15 mm of subsidence, compared with 1.51 +/- 0.32 mm for the FAP (P = 0.045). No significant difference was found in the maximal load to medial condyle fixation failure between either plating construct (P = 0.204). CONCLUSIONS: The results of this study demonstrate that dual-plate fixation allows less subsidence in this bicondylar tibial plateau cadaveric model when compared to isolated locked lateral plates. This may raise concerns about the widespread use of isolated lateral locked plate constructs in bicondylar tibial plateau fractures.