Spinal Manifestations of Skeletal Dysplasia: A Practical Guide for Clinical Diagnosis.

Skeletal dysplasias are a group of genetic conditions defined by atypical bone or cartilage growth and development. Skeletal abnormalities include short stature, limb deformity, joint contracture, and spinal deformity. Over 90% of disorders have a known genetic mutation that can definitively determine the diagnosis. As patients may present with a primary spinal concern, a careful clinical and radiographic evaluation can allow the physician to develop a working diagnosis to guide additional evaluation. Spinal manifestations include scoliosis and kyphoscoliosis, cervical instability, cervical kyphosis, thoracolumbar kyphosis, spinal stenosis, and atypical vertebral body morphology. An understanding of the affected conditions, prevalence, and natural history of these radiographic findings aids the orthopaedic surgeon in establishing a diagnosis and guides appropriate orthopaedic care.

Use of Surgical Adjuvants Does Not Decrease Recurrence of Aneurysmal Bone Cysts in Surgical Intervention With Pediatric Patients.

BACKGROUND: Aneurysmal bone cysts (ABCs) are benign active tumors often requiring intralesional curettage with or without adjuvants. The primary aim of this study was to analyze whether recurrence is influenced by the use of surgical adjuvants in pediatric patients with ABCs. Secondary aims examined recurrence rates based on age, sex, and physeal contact. METHODS: A retrospective review was performed at a tertiary pediatric hospital from 2004 to 2020. Inclusion criteria consisted of patients treated surgically for histologically confirmed ABCs with a minimum of 6 months follow-up. Patients with treatment for a recurrent tumor or incomplete records were excluded. Patient demographics, location of the lesion, treatment technique, and incidence of recurrence were collected. Statistical analyses were performed using STATA. RESULTS: There were 129 patients (74 males and 55 females) with a mean age of 11.5 ± 4.1 years and an average follow-up of 29.0 ± 25.4 months. The most common locations for ABCs were the femur and tibia. Of the patients, 53.5% had tumors abutting the physis, 28.7% had no physeal contact, and 17.8% had insufficient imaging to evaluate physeal contact. Surgical adjuvants (high-speed burr, coagulation, liquid nitrogen, and/or hydrogen peroxide) were used in 91 of the 129 cases (70.5%). There was no significant difference in recurrence when comparing those who received an adjuvant and those who did not (25.3% vs 23.7%, P = 1.000). Physeal contact was also not significantly associated with recurrence ( P = 0.146). Finally, patients younger than 6 years old were significantly more likely to have recurrence compared with those 6 years old or older (66.7% vs 21.7%, P = 0.007). CONCLUSION: Our study found no association between the use of surgical adjuvants and the risk of recurrence after intralesional curettage for ABCs. Although our study did demonstrate that patients 6 years old or younger had an increased rate of recurrence, no significant association was found regarding physeal contact or sex. These data indicate that surgical adjuvant may not affect the recurrence rates of pediatric patients with ABCs. LEVEL OF EVIDENCE: Level III. This retrospective review compares rates of recurrence based on the choice of surgical adjuvant.

Treatments and Sequelae of Pediatric Pathologic Proximal Femur Fractures Due to Benign Bone Cyst.

BACKGROUND: The proximal femur is a common location for pathologic fractures in children, yet there is little published information regarding this injury. The purpose of this study was to investigate the outcomes of pediatric pathologic proximal femur fractures due to benign bone tumors. METHODS: A retrospective review of patients treated for pathologic proximal femur fractures from 2004 to 2018 was conducted. Inclusion criteria were age below 18 years and pathologic proximal femur fracture secondary to a benign bone tumor. Patients were excluded if they had <1 year of follow-up. Medical charts and serial radiographs were reviewed for fracture classification, underlying pathology, treatment, complications, and time to fracture healing. RESULTS: A total of 14 patients were included. Mean age was 6±3 (3 to 11) years, and mean follow-up was 44±21 (22 to 86) months. Index treatment was spica casting in 9/14 (68%) patients, while 5/14 (32%) were treated with internal fixation. Of the 9 patients initially treated with casting, 22% (2/9) required repeat spica casting at a mean of 0.6 months after index treatment, 67% (6/9) required internal fixation at a mean of 20.3 months after index treatment, and 11% (1/9) did not require revision treatment. Eighty-eight percent (8/9) of patients treated with casting required revision treatment compared with 40% (2/5) of those treated with internal fixation (P=0.05). Nonunion occurred after 1 refracture, malunion with coxa vara occurred in 2 fractures, and the remaining 11/14 (84%) fractures had a union at a mean of 4.9±3.0 months All cases of malunion occurred in patients initially treated nonoperatively. There were 19 distinct complications in 10/14 (71%) patients. The incidence of any revision surgery was 64% (9/14). CONCLUSIONS: In this series, pediatric pathologic proximal femur fractures demonstrated prolonged time to union, high incidence of revision surgery (64%), and substantial complication rate (71%). In children with pathologic proximal femur fractures, treatment with internal fixation is recommended as this series showed a 78% failure rate of initial conservative management. LEVEL OF EVIDENCE: Level IV.

Coaching and Surgical Performance.

Surgical coaching is a form of mentoring that can improve surgical performance. While professional athletes have coaching their entire career, other professions, such as medicine, law, and education, are expected to manage their own improvement in performance over their careers. Methods of surgical coaching and the pros and cons of coaching to improve surgical performance and improve patient safety will be presented.

How and When to Transition to the Next Phase: Reflections.

With Americans living longer, many physicians and surgeons have extended their medical and surgical practice life beyond the traditional 65-year-old retirement age. As retirement is inevitable, planning for that eventuality, which in early practice years appears unnecessary, is in fact an exercise which will pay dividends at the time of retirement. Two senior orthopaedic surgeons provide insight on the 2 main issues concerning retirement: how to prepare for retirement while in active practice, and factors to consider as to the timing of that major life event.

Using a dedicated spine radiology technologist is associated with reduced fluoroscopy time, radiation dose, and surgical time in pediatric spinal deformity surgery.

STUDY DESIGN: Retrospective comparative study OBJECTIVES: The goal of this study was to investigate fluoroscopy time and radiation exposure during pediatric spine surgery using a dedicated radiology technologist with extensive experience in spine operating rooms. Repetitive use of intraoperative fluoroscopy during posterior spinal fusion (PSF) exposes the patient, surgeon, and staff to radiation. METHODS: Retrospective review was conducted on patients with posterior spinal fusion (PSF) of ≥ 7 levels for adolescent idiopathic scoliosis (AIS) at a pediatric hospital from 2015 to 2019. Cases covered by the dedicated radiology technologist (dedicated group) were compared to all other cases (non-dedicated group). Surgical and radiologic variables were compared between groups. RESULTS: 230 patients were included. 112/230 (49%) were in the dedicated group and 118/230 (51%) were in the non-dedicated group. Total fluoroscopy time was significantly reduced in cases with the dedicated technologist (46 s) compared to those without (69 s) (p = 0.001). Radiation dose area product (DAP) and air kerma (AK) were reduced by 43% (p < 0.001) and 42% (p < 0.001) in the dedicated group, respectively. The dedicated group also had reduced total surgical time (4.1 vs. 3.5 h; p < 0.001) and estimated blood loss (447 vs. 378 cc (; p = 0.02). Multivariate regression revealed that using a dedicated radiology technologist was independently associated with decreased fluoroscopy time (p = 0.001), DAP (p < 0.001), AK (p < 0.001), surgical time (p < 0.001), and EBL (p = 0.02). CONCLUSIONS: In AIS patients undergoing PSF, using a dedicated radiology technologist was independently associated with significant reductions in fluoroscopy time, radiation exposure, surgical time, and EBL. This adds to the growing body of research demonstrating that the experience level of the team-not just that of the surgeon-is necessary for optimal outcomes. LEVEL OF EVIDENCE: III.

High Parental Anxiety Increases Narcotic Use in Adolescent Patients Following Spinal Fusion.

BACKGROUND: Parental mental status and behavior may influence postoperative recovery and the use of pain medication. The purpose of this study is to identify if parents with high anxiety are associated with prolonged narcotic use in adolescent patients following posterior spinal fusion surgery. Prolonged narcotic use in this study was defined as opioid use at their first postoperative visit. METHODS: AIS patients age 11 to 20 years undergoing posterior spinal fusion and a parent were prospectively enrolled. At the preoperative appointment, patients completed the Spence Children's Anxiety Scale and parents completed the State-Trait Anxiety Inventory. High parental anxiety was defined as 1 SD above the normative mean. At the first postoperative visit, patients were asked about medication use. RESULTS: A total of 58 patients (49 females and 9 males) were enrolled. Overall, 29% (17/58) of parents had a high general anxiety trait on the State-Trait Anxiety Inventory and 71% (41/58) had normal general anxiety. Of the patients whose parents had high general anxiety, 47% (8/17) were still taking narcotics at their first postoperative visit compared with 20% (8/41) of patients with normal anxiety parents (P=0.03). CONCLUSIONS: Patients with high general anxiety parents were more than twice as likely to still be on narcotics at their first postoperative visit. This information can be used to counsel families on the impact of anxiety on narcotic usage. LEVEL OF EVIDENCE: Level II-prognostic studies-investigating the effect of a patient characteristic on the outcome of the disease.

Scoliosis-specific exercises: A state of the Art Review.

Scoliosis-specific exercises are prescribed and used by many centers either primarily or as an adjunct to other treatment methods for adolescent idiopathic scoliosis of mild to moderate severity. These methods are often used in Europe and are being used in the United States with increasing frequency. There are few publications about these methods in the spine or orthopedic literature. We have performed a review of the relevant literature from the PubMed database to evaluate the evidence for effectiveness of these treatments. We found no studies that provide valid evidence that an exercise method prevents progression of AIS (adolescent idiopathic scoliosis) in patients during their peak growth period. We report our review of selected relevant efforts and provide a description of many of the available treatment programs.

High Satisfaction in Adolescent Idiopathic Scoliosis Patients on Enhanced Discharge Pathway.

BACKGROUND: Recently, there have been several reports of using an enhanced discharge pathway following posterior spinal fusion (PSF) in patients with adolescent idiopathic scoliosis (AIS). No previous studies have prospectively examined patient satisfaction of patients with AIS using an enhanced discharge pathway. The purpose of this study was to evaluate patient satisfaction with an enhanced discharge pathway for PSF and whether patients felt that their length of stay was appropriate. METHODS: Patients with AIS undergoing PSF were prospectively enrolled. At their first postoperative clinic visit, patients were administered a survey regarding their experience. RESULTS: Of the 46 patients enrolled (mean age, 14 y), 1 was discharged on postoperative day (POD) 2, 33 were discharged on POD 3, 9 were discharged on POD 4, and 3 were discharged on POD 5. Eighty (37/46) of patients felt that they were discharged at an appropriate time, whereas 20% (9/46) felt they were discharged too early. Patients who felt they were discharged at an appropriate time (mean, 3.2 d) had a trend toward shorter stays than those who felt they were discharged too early (mean, 3.7 d). Overall patient satisfaction of hospital stay was high with a mean of 9 on a 10-point scale (range, 1 to 10). There was no correlation between length of stay and patient satisfaction (P=0.723). Patients who felt they were discharged early had a significantly higher mean FACES pain scores than those who felt they were discharged about right both as inpatients (mean, 4.8 vs. 3.4; P=0.0319) and at their first postoperative clinic visit (5.4 vs. 2.9; P=0.004). CONCLUSIONS: Eighty percent of patients with AIS who underwent PSF felt that the time of discharge was appropriate with an enhanced discharge pathway. There was no correlation between patient satisfaction and length of stay. LEVEL OF EVIDENCE: Level II.

Side Plank Pose Exercises for Adolescent Idiopathic Scoliosis Patients.

BACKGROUND: Fishman et al. reported that side plank poses asymmetrically strengthened the convex side of the curve and decreased primary Cobb angle by 49% among compliant patients with adolescent idiopathic scoliosis (AIS). METHODS: AIS patients with curves of 10° to 45° were randomized into the front plank (control) or side plank group. The side plank was performed with their curve convex down. A weekly survey monitored compliance, defined by completing poses 4 or more times a week. RESULTS: A total of 64 patients were enrolled; 34% (22 of 64) of patients (mean age = 13 years) were compliant. In the control group, there were 11 compliant patients with 6 undergoing brace treatment. At enrollment, they had a mean Cobb angle of 30° (range: 14°-40°) and mean scoliometer reading of 13°. At 6 months, they had a mean Cobb angle of 30° (range: 14°-42°) and mean scoliometer of 12°. In the side plank group, there were 11 compliant patients with 5 undergoing brace treatment. At enrollment, they had a mean Cobb angle of 32° (range: 21°-44°) and mean scoliometer reading of 12°. At 6 months, they had a mean Cobb angle of 31° (range: 17°-48°) and a mean scoliometer reading of 13°. There were no significant changes in either the control or side plank group in regards to primary Cobb angle (control: P = .53, side plank: P = .67) or scoliometer (control: P = .22, side plank: P = .45). CONCLUSION: There were no significant changes in primary Cobb angle or scoliometer after 6 months of side plank exercises. In contrast to a prior study, there was no improvement in curve magnitude in AIS patients performing side plank exercises.

Comparison of Ponte Osteotomies and 3-Column Osteotomies in the Treatment of Congenital Spinal Deformity.

BACKGROUND: Congenital spinal deformity (CSD) has traditionally been treated with 3-column osteotomies [hemivertebrectomy (HV) or vertebral column resection (VCR)] to address rigid deformities. Alternatively, multiple Ponte osteotomies (PO) may provide correction while minimizing risk. The purpose of this study was to compare safety and outcomes of patients undergoing surgical treatment for CSD with these 3 procedures. METHODS: Retrospective review of CSD patients treated with posterior spinal fusion between 1996 to 2013. Patients treated with multiple Ponte osteotomies (PO group) were compared with those managed with 3-column osteotomies (HV/VCR group). Patients with previous instrumentation, isolated cervical deformity, growing spine instrumentation, or <2 year follow-up were excluded. Deformity angular ratio (DAR) was calculated as curve magnitude divided by number of levels of the deformity. RESULTS: There were 49 patients [17 PO, 32 HV/VCR (26 HV, 6 VCR)]. For the PO group, mean age was 14 years, and they had an average of 4 ponte osteotomies and 11 levels fused. Mean total DAR was 25 and mean number of congenital anomalies was 1.8 in the PO group. The HV/VCR group had a mean age of 7 years and 5 levels fused. Mean total DAR was 28 and mean number of congenital anomalies was 2.1 in the HV/VCR group. Patients had a mean of 54.1% correction of coronal deformity in the PO group and 54.4% in the HV/VCR group (P=0.78). Signal changes were observed less frequently with PO (1/17) and HV (1/26) than with VCR (4/6), P=0.001. Revision rates were 17.6% (3/17) in the PO group and 37.5% (12/32) in the HV/VCR group (P=0.35). CONCLUSIONS: Patients with CSD and a mean total DAR of 25 treated with multiple PO and long fusions had correction comparable with the HV/VCR group. Patients treated with VCR had the highest incidence of signal changes and postoperative neurologic deficits. LEVEL OF EVIDENCE: Level III.

Preventing Distal Junctional Kyphosis by Applying the Stable Sagittal Vertebra Concept to Selective Thoracic Fusion in Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Multicenter retrospective review. OBJECTIVE: To assess the effectiveness of using the stable sagittal vertebra (SSV) for selecting the lowest instrumented vertebrae (LIV) to prevent distal junctional kyphosis (DJK) in selective thoracic fusions. SUMMARY OF BACKGROUND DATA: Cho et al. reported that including the SSV in a fusion decreased the rate of DJK in thoracic hyperkyphosis. METHODS: A retrospective review was performed of patients from two pediatric hospitals with adolescent idiopathic scoliosis who underwent selective posterior thoracic fusion with the LIV at L2 or above from 2000 to 2012. Patients with less than 2 years' follow-up were excluded. The primary outcome measure was DJK, defined radiographically as ≥10° between the superior end plate of the LIV and the inferior end plate of the vertebra below on a standing lateral radiograph. We investigated the SSV, which was defined as the vertebral level at which 50% of the vertebral body was in front of the posterior sacral vertical line (PSVL) on a standing lateral radiograph. This particular definition was referred to as SSV. RESULTS: A total of 113 patients met the inclusion criteria. Mean age was 14.4 years. Mean Cobb angle was 58°. The overall rate of DJK was 7% (8/113). When the LIV was superior to SSV, the rate of DJK was 17% (8/46) versus 0% (0/67) when the LIV was at or inferior to SSV (p=.01). The rates of DJK for patients with the LIV one, two, and three levels above SSV were 17% (4/24), 7% (1/14), and 43% (3/7), respectively. There was no significant association between preoperative or postoperative maximum kyphosis, thoracic kyphosis, thoracolumbar kyphosis, pelvic incidence, sagittal balance or coronal balance, and development of DJK. CONCLUSION: Although LIV selection is complex, choosing the LIV at or below the SSV is a simple rule that minimizes the risk of DJK. LEVEL OF EVIDENCE: Level IV.

Pain is the Greatest Preoperative Concern for Patients and Parents Before Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis.

STUDY DESIGN: Prospective cross-sectional study. OBJECTIVE: To evaluate patients' and parents' concerns so they can be addressed with appropriate preoperative counseling. SUMMARY OF BACKGROUND DATA: Despite much research on outcomes for posterior spinal fusion (PSF) in adolescent idiopathic scoliosis (AIS), little is available about preoperative fears or concerns. METHODS: Patients with AIS undergoing PSF, their parents, and surgeons were prospectively enrolled and asked to complete a survey on their fears and concerns about surgery at their preoperative appointment. RESULTS: Forty-eight patients and parents completed surveys. Four attending pediatric spine surgeons participated and submitted 48 responses. Mean age of patients was 14.2 years. On a scale of 0 to 10, mean level of concern reported by parents (6.9) was higher than that reported by patients (4.6). Surgeons rated the procedure's complexity on a scale of 0 to 10 and reported a mean of 5.2. Neither patients' nor parents' level of concern correlated with the surgeons' assessment of the procedure's complexity level (R = 0.19 and 0.12, P = 0.20 and P = 0.42, respectively). Top three concerns for patients were pain (25%), ability to return to activities (21%), and neurologic injury (17%). Top three concerns for parents were pain (35%), neurologic injury (21%), and amount of correction (17%). Top three concerns for surgeons were postoperative shoulder balance (44%), neurologic injury (27%), and lowest instrumented vertebrae selection (27%). Patients reported the same concerns 23% of the time as parents, and 17% of the time as surgeons. Parents and surgeons reported the same concerns 21% of the time. CONCLUSION: Pain was the greatest concern for both patients and parents but was rarely listed as a concern by surgeons. Parent and patient level of concern did not correlate to the surgeon's assessment of the procedure's complexity. Neurologic injury was a top concern for all groups, but otherwise there was little overlap between physician, patient, and parent concerns. LEVEL OF EVIDENCE: 3.

Sacral Alar Iliac (SAI) Screws Fail 75% Less Frequently Than Iliac Screws in Neuromuscular Scoliosis.

BACKGROUND: Despite recent popularity of sacral alar iliac (SAI) screws for fusion to the pelvis for neuromuscular scoliosis, there are little data regarding the failure rate of this technique compared with traditional modes of iliac fixation. Theoretical advantages of the SAI screws are obviating the need for a rod to iliac screw connector and a lower implant profile. The purpose of this study is to determine whether SAI screws have fewer failures than iliac screws in neuromuscular scoliosis. METHODS: Review of neuromuscular patients treated with posterior spinal fusion with pelvic fixation from 2004 to 2012 with minimum 2-year follow-up was conducted. Medical records and imaging studies were reviewed. Patients were divided into 2 groups based on the type of pelvic fixation (SAI or iliac screws), and implant failures were compared between the groups. RESULTS: A total of 101 patients were reviewed, including 55 patients with iliac screws and 46 patients with SAI screws. Implant failures included: disengagement of the rod to iliac screw connector (10%, 10/101), separation of screw head from screw shaft (4%, 4/101), and set screw disengagement (2%, 2/101). The SAI group had a lower implant failure rate (7%, 3/46) compared with the iliac screw group (24%, 13/55) (P=0.031). Rod to iliac screw connectors failed in 18% (10/55) of patients. There were significantly less surgical revisions in the SAI group (2%, 1/46) for pelvic screw prominence compared with the iliac screw group (11%, 6/55) (P=0.027). CONCLUSIONS: SAI screws had a lower rate of implant failure and revision surgery compared with iliac screws. If rod to screw connector failures are excluded, the failure rate of SAI screws of 6.5% (3/46) is similar to that of iliac screws 5.5% (3/55); therefore, the most important advantage of the SAI technique may be obviating the need for a screw to rod connector. LEVEL OF EVIDENCE: Level III.

Lateral Femoral Cutaneous Nerve Palsy After Spinal Fusion for Adolescent Idiopathic Scoliosis (AIS).

STUDY DESIGN: Prospective study of consecutive patients. OBJECTIVE: The purpose of the study was to evaluate the incidence, risk factors, and time to resolution of lateral femoral cutaneous nerve palsy (LFCNP) after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). SUMMARY OF BACKGROUND DATA: No prior studies have prospectively evaluated the prevalence of LFCNP exclusively in the treatment of AIS. METHODS: Between June 2014 and May 2015, patients undergoing PSF for AIS were examined preoperatively, postoperatively, and at follow-up clinic visits until the resolution of the LFCNP. All neurologic examinations were performed by attending pediatric orthopedic surgeons. Patients who underwent staged, revision or anterior procedures, had preoperative neurologic deficits or neuropathy, were excluded. RESULTS: A total of 55 patients with an average age of 14 years (10-21) were enrolled. Twenty-five percent (14/55) of patients had a postoperative LFCNP. There were no other postoperative neurologic deficits. Of the 14 patients with an LFCNP, 57% of these were bilateral. Fourteen percent (2/14) of these patients had absent sensation to light touch, whereas 85% (12/14) had decreased sensation. No patients reported experiencing pain associated with the LFCNP or tenderness when the anterolateral thigh was palpated. The LFCNP did not limit postoperative mobilization or prolong hospital stay. The LFCNP was noted to resolve in an average of 3.6 days (1-18); 6/14 (43%) resolved after 1 day. No correlation was observed between occurrence of LFCNP and sex, age, height, body mass index, length of fusion, Cobb angle, or blood loss. The occurrence of LFCNP was associated with heavier weight (P = 0.032) and longer operative times (P = 0.016). Resolution of the LFCNP was associated with longer operative time (P = 0.010). CONCLUSION: LFCNP occurred in 25% of AIS patients undergoing PSF. Risk of LFCNP increased with longer operative times and heavier patient weight. On average, LFCNP resolved in less than 4 days and did not cause any pain or limitations. LEVEL OF EVIDENCE: 2.

How do you know it is true? Integrity in research and publications: AOA critical issues.

High-quality medical care is the result of clinical decisions based upon scientific principles garnered from basic, translational, and clinical research. Information regarding the natural history of diseases and their responses to various treatments is introduced into the medical literature through the approximately one million PubMed journal articles published each year. Pharmaceutical and device companies, universities, departments, and researchers all stand to gain from research publication. Basic and translational research is highly competitive. Success in obtaining research funding and career advancement requires scientific publication in the medical literature. Clinical research findings can lead to changes in the pattern of orthopaedic practice and have implications for the utilization of pharmaceuticals and orthopaedic devices. Research findings can be biased by ownership of patents and materials, funding sources, and consulting arrangements. The current high-stakes research environment has been characterized by an increase in plagiarism, falsification or manipulation of data, selected presentation of results, research bias, and inappropriate statistical analyses. It is the responsibility of the orthopaedic community to work collaboratively with industry, universities, departments, and medical researchers and educators to ensure the integrity of the content of the orthopaedic literature and to enable the incorporation of best practices in the care of orthopaedic patients.

Measurement Variability in the Evaluation of the Proximal Junction in Distraction-based Growing Rods Patients.

BACKGROUND: Proximal junctional kyphosis (PJK) is a known complication of spinal fusion and has been shown to occur in the setting of growing rod instrumentation. Previous studies have shown good reliability in measuring PJK in adolescent idiopathic scoliosis. METHODS: Four pediatric orthopaedic spine surgeons measured the proximal junction in 10 patients with growing rod instrumentation using 2 methods. In method 1, measurements were made from the inferior endplate of the upper instrumented vertebrae (UIV) to the superior endplate of 1 level above the UIV. In method 2, measurements were made from the inferior endplate 2 levels below the UIV to the superior endplate 2 levels above the UIV. These measurements were repeated 1 week later. RESULTS: Method 1 had an intraobserver variability of ±13.2 degrees and interobserver variability of ±21.6 degrees, whereas method 2 had an intraobserver variability of ±18.3 degrees and interobserver variability of ±20.7 degrees. CONCLUSIONS: Interobserver variability of PJK is >20 degrees. As PJK is commonly defined as >10 degrees of kyphosis above the UIV, measurement of PJK in patients with distraction-based growing rods on lateral radiographs has too much variability to be useful. LEVEL OF EVIDENCE: Level III-diagnostic studies.