Age-Stratified Outcomes of Mehta Casting in Idiopathic Early-Onset Scoliosis: A Multicenter Review.

BACKGROUND: This study provides age-stratified outcomes of cast treatment for idiopathic early-onset scoliosis. METHODS: This is a multicenter, retrospective review of patients with idiopathic early-onset scoliosis treated with Mehta casting at 4 tertiary children's hospitals between 2001 and 2016. The inclusion criteria were idiopathic early-onset scoliosis and a minimum follow-up of 2 years after casting ended. The exclusion criteria were <2 casts, >3 casts at an outside facility, and a major curve of <20° pre-treatment. Subjects were grouped by age at first cast: <18 months, 18 to <24 months, 2 to <3 years, 3 to <4 years, and ≥4 years. RESULTS: There were 134 patients with a mean follow-up of 5.2 years (95% confidence interval [CI], 4.8 to 5.5 years) after casting. Prior to treatment, the major curve was not significantly different between the various age groups and was a mean of 50.4° (95% CI, 48.0° to 52.8° [range, 22° to 109°]). Of the <18-month group (n = 59), at the final follow-up at a mean of 7.4 years (95% CI, 6.8 to 8.1 years) of age, 75% had scoliosis of <15°, and 6.8% had undergone a surgical procedure or had a major curve of ≥50°. The results declined in the 18 to <24-month group (n = 30), with a major curve of <15° at the final follow-up at 8.5 years (95% CI, 7.3 to 9.7 years) of age in 33% (p < 0.001), and 17% having undergone a surgical procedure or had a major curve of ≥50°, with results nearly identical in the 2 to <3-year group (n = 21). The results continued to decline with increasing age; 23% of the 3 to <4-year group had a major curve of <15° at the final follow-up, and 31% had undergone a surgical procedure or had scoliosis of ≥50°. Of the ≥4-year group, just 9.1% had scoliosis of <15° (p < 0.0001 compared with the <18-month group), and 64% had undergone a surgical procedure or had scoliosis of ≥50°. CONCLUSIONS: Children who underwent casting prior to 18 months of age were more likely to have a major curve of <15° at a minimum 2-year follow-up after casting. LEVEL OF EVIDENCE: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

Baseline patient reported outcome measurement information system (PROMIS) scores in children with idiopathic scoliosis and their relation to the SRS-22.

PURPOSE: PROMIS is becoming the most commonly utilized patient-reported outcome measure (PROM) in adult orthopaedics, but its adoption has lagged in pediatrics. Limited baseline data exists in pediatric-specific orthopaedic diagnoses. The objective of this study was to determine baseline PROMIS scores in patients with idiopathic scoliosis and to evaluate for correlations with the SRS-22. METHODS: This was a retrospective analysis of prospectively collected data from six tertiary care pediatric hospitals between July 2016 and July 2018. Patients with a diagnosis of idiopathic scoliosis, adequate radiographs for measurement and completion of PROMIS and SRS-22 questionnaires from the same visit were included. Only the first visit during the study period was included for each subject. Post-operative patients were excluded. Spearman correlations were performed between four PROMIS domains (Pain interference [PI], Mobility [M], Peer Relationships [PR] and Upper Extremity [UE]) and SRS-22 domains. PROMIS scores are calibrated such that 50 is the median value in a population and 10 points is equivalent to one standard deviation. RESULTS: 986 patients with a mean age of 14.6 years were included, 79.8% of which were female. The mean major curve was 33.0° (range: 10-102). The major curve was thoracic in 56.5%, thoracolumbar in 24.4% and lumbar in 19.1% of subjects. The mean PROMIS domain scores were: Pain Interference 44.5 (IQR 17.7); Mobility 52.7 (IQR 12.5); Peer Relationships 55.7 (IQR 15.0); Upper Extremity 53.4 (IQR 7.7). Correlations existed between PROMIS Pain Interference and SRS-22 pain (r = 0.704, p < 0.001) and PROMIS Mobility and SRS-22 function (r = 0.53, p < 0.001). Significant ceiling effects existed in SRS-22 Function (29.9%), Pain (19.2%) and Satisfaction (30.3%) but only for PROMIS Peer Relationships (42.1%). CONCLUSIONS: PROMIS domain scores for patients with AIS are within normal population limits. PROMIS correlates well with SRS-22 in overlapping domains, and fewer domains demonstrate a ceiling effect. There was no relationship between the magnitude of scoliosis and PROMIS domain scores. LEVEL OF EVIDENCE: II.

A multicenter study to evaluate the pharmacokinetics and safety of liposomal bupivacaine for postsurgical analgesia in pediatric patients aged 6 to less than 17 years (PLAY).

STUDY OBJECTIVE: To evaluate the pharmacokinetics and safety of liposomal bupivacaine in pediatric patients undergoing spine or cardiac surgery. DESIGN: Multicenter, open-label, phase 3, randomized trial (PLAY; NCT03682302). SETTING: Operating room. PATIENTS: Two separate age groups were evaluated (age group 1: patients 12 to <17 years undergoing spine surgery; age group 2: patients 6 to <12 years undergoing spine or cardiac surgery). INTERVENTION: Randomized allocation of liposomal bupivacaine 4 mg/kg or bupivacaine hydrochloride (HCl) 2 mg/kg via local infiltration at the end of spine surgery (age group 1); liposomal bupivacaine 4 mg/kg via local infiltration at the end of spine or cardiac surgery (age group 2). MEASUREMENTS: The primary and secondary objectives were to evaluate the pharmacokinetics (eg, maximum plasma bupivacaine concentrations [Cmax], time to Cmax) and safety of liposomal bupivacaine, respectively. MAIN RESULTS: Baseline characteristics were comparable across groups. Mean Cmax after liposomal bupivacaine administration was lower versus bupivacaine HCl in age group 1 (357 vs 564 ng/mL); mean Cmax in age group 2 was 320 and 447 ng/mL for spine and cardiac surgery, respectively. Median time to Cmax of liposomal bupivacaine occurred later with cardiac surgery versus spine surgery (22.7 vs 7.4 h). In age group 1, the incidence of adverse events (AEs) was comparable between liposomal bupivacaine (61% [19/31]) and bupivacaine HCl (73% [22/30]). In age group 2, 100% (5/5) and 31% (9/29) of patients undergoing spine and cardiac surgery experienced AEs, respectively. AEs were generally mild or moderate, with no discontinuations due to AEs or deaths. CONCLUSIONS: Plasma bupivacaine levels following local infiltration with liposomal bupivacaine remained below the toxic threshold in adults (~2000-4000 ng/mL) across age groups and procedures. AEs were mild to moderate, supporting the safety of liposomal bupivacaine in pediatric patients undergoing spine or cardiac surgery. Clinical trial number and registry URL: ClinicalTrials.gov identifier: NCT03682302.

Pedicle Screw With Increased Cortical Purchase Can Be Inserted With Same Accuracy as the Screw in Straightforward Trajectory Using 3D Modeling Landmarks.

STUDY DESIGN: Comparison, in terms of insertion accuracy and biomechanical performance, between an increased cortical purchase and straightforward pedicle screw trajectory. OBJECTIVE: This study aims to compare a trajectory with increased cortical purchase to the more common straightforward trajectory in terms of strength and insertion accuracy using real-time navigation. SUMMARY OF BACKGROUND DATA: In previous studies, it was suggested that pedicle screw pullout strength is strongly correlated with bone mineral density, and using a more cortical tract allows a greater portion of the denser bone, the cortex, to be in contact with the screw. In light of this advantage, an insertion technique has been proposed more recently, to increase the cortical purchase to maximize screw thread contact with cortical bone. It is performed inserting the screw with reduced transverse inclination and results in cortical bone purchase in the lateral portion of the pedicle. METHODS: Eight T1 and eight T3 vertebra models were reconstructed in Mimics Suite (Materialise, Leuven, Belgium) using CT data obtained with a Medtronic O-arm. Using a previously developed computer algorithm, we calculated all achievable safe trajectories for pedicle screw placement ensuring a minimal distance of 0.5 mm between screw and pedicle edges. For both vertebrae, among these, the straightest and the most convergent trajectories with the calculated insertion region greater than 15% of the total were selected to safely instrument the vertebrae, respectively, as ICP and straightforward techniques. The straightforward technique was planned with a transverse angle of 22.50° in both vertebrae whereas the ICP was planned with a transverse angle of 12.50° for T1 and 2.5° for T3. The screws were implanted by a surgeon experienced in straightforward insertion, and other independent investigators measured placement accuracy and mechanical performance. RESULTS: The transverse screw angles for T1 and T3 with straightforward technique had average values of 24.93° ± 2.96° and 23.53° ± 2.70°, respectively. For the ICP technique, the average values were 15.60° ± 2.95° for T1 and 2.29° ± 1.55° for T3. The resultant errors associated with screw placement for T1 and T3 were not significantly different (p > .05). The pullout failure loads with straightforward techniques ranged from 756 ± 164 N in T1 to 703 ± 74 N in T3 and were not significantly different (p > .05) from the values of 699 ± 84 N for T1 and of 732 ± 113 N measured for the ICP. CONCLUSIONS: For the upper thoracic vertebrae tested, despite the use of shorter screws, the insertion technique with increased cortical purchase, in biomechanical terms, is comparable with the straightforward trajectory. Using guidance, the proposed ICP technique was performed with the same accuracy as the popular straightforward technique. LEVEL OF EVIDENCE: Level V.

Cobb angle measurements on digital radiographs using Bunnell scoliometer: Validation of the method.

BACKGROUND: Electronic rulers on computer screen are used to measure the Cobb angle (CA) instead of traditional methods with rulers, protractors and pens. The variety of software used to assess radiographs might make the CA measurements cumbersome in everyday clinical practice. OBJECTIVE: The aim of the study was to verify the method of CA measurements on digital radiographs using Bunnell scoliometer (BS). METHODS: Eighty patients with idiopathic scoliosis were enrolled into the study. CA of each curve was measured by use of Centricity software and BS. CA on 30 randomly chosen patients were measured 3 times by one researcher using only scoliometer. Three researchers measured CA on the same 30 radiographs using BS. RESULTS: The mean CA of 224 curves measured by Centricity and BS were 29° ± 12.2° and 28° ± 11.7°, respectively. The ICC for agreement for 2 methods was 0.96 with SEM of 1.7°. Excellent intra- and interobserver reliability of CA measurements with scoliometer was noted: ICC of 0.96 with SEM of 1.4° and ICC of 0.93 with SEM of 1.9°, respectively. CONCLUSIONS: The study revealed excellent reliability of CA measurements on digital radiographs using the BS. The proposed method of using the Bunnell scoliometer for CA measurements may be clinically useful.

Anterior cervical corpectomy and fusion for blastomycosis causing destruction of C6 vertebra: a case report.

INTRODUCTION: We describe a patient who had cervical spine osteomyelitis caused by Blastomyces dermatitidis that resulted in cord compression and cervical spine instability. CASE PRESENTATION: A 25-year-old Hispanic woman presented with fever, sweats, neck pain, and an enlarging neck mass with purulent discharge after sustaining a C6 vertebral body fracture. Magnetic resonance imaging confirmed C6 vertebral osteomyelitis, demonstrated by vertebral body destruction, cervical spine instability, prevertebral abscess, and spinal cord compression. She underwent C6 anterior cervical corpectomy and fusion, with fungal cultures confirming Blastomyces dermatitidis. CONCLUSIONS: Anterior cervical corpectomy and fusion successful debrided, decompressed, and restored cervical spine stability in a patient with vertebral osteomyelitis caused by Blastomyces dermatitidis. The patient was subsequently treated with a 1-year course of itraconazole and had no recurrence of infection 4 years postoperatively.

Size variability of the human anterior cruciate ligament insertion sites.

BACKGROUND: Current trends in anterior cruciate ligament reconstruction (ACLR) have been toward anatomical reconstruction that restores the normal size and location of the anterior cruciate ligament insertions and its 2 bundles, the posterolateral (PL) and anteromedial (AM) bundles. This has resulted in a more individualized approach to ACLR. Several studies have shown that the size of the anterior cruciate ligament insertion sites is variable; however, these studies are limited by use of relatively small sample sizes and cadaveric specimens. PURPOSE: This study was undertaken to evaluate the in vivo size variability of the anterior cruciate ligament insertion sites and its AM and PL bundles during arthroscopy in a large series of patients and to correlate these findings with individuals' physical characteristics (height, weight, and body mass index). STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: In 137 patients undergoing ACLR during the first 6 months after injury, the femoral and tibial anterior cruciate ligament insertion sites and the 2 bundles were identified, marked with electrocautery, and measured with an arthroscopic ruler. Additionally, physical characteristics of the patients, including self-reported height, weight, and body mass index, were recorded. RESULTS: The tibial anterior cruciate ligament insertion site had a mean length of 17.0 ± 2.0 mm. The tibial AM bundle length was 9.1 ± 1.2 mm and the width was 9.2 ± 1.1 mm. The tibial PL bundle insertion site length averaged 7.4 ± 1.0 mm and the width averaged 7.0 ± 1.0 mm. The femoral insertion sites had a mean length of 16.5 ± 2.0 mm. The length of the femoral AM bundle insertion site averaged 9.2 ± 1.2 mm and the width averaged 8.9 ± 0.9 mm. The femoral PL bundle insertion site length averaged 7.1 ± 1.1 mm and the width averaged 6.9 ± 1.0 mm. There were significant positive correlations between patient height and weight (P < .05) with femoral and tibial anterior cruciate ligament insertion site length, tibial PL bundle insertion site length, femoral AM bundle insertion site length, and tibial AM bundle and PL bundle insertion site areas. However, the coefficients of determination values were low (1.0% to 19.4%). CONCLUSION: There is a large variation in size of the anterior cruciate ligament insertion sites and the AM and PL bundles. Additionally, there are significant but weak correlations between the size of the insertions and height, weight, and body mass index of the individual patient.

Optical coherence tomography detection of subclinical traumatic cartilage injury.

OBJECTIVES: Posttraumatic arthritis is a major cause of disability. Current clinical imaging modalities are unable to reliably evaluate articular cartilage damage before surface breakdown, when potentially reversible changes are occurring. Optical coherence tomography (OCT) is a nondestructive imaging technology that can detect degenerative changes in articular cartilage with an intact surface. This study tests the hypothesis that OCT detects acute articular cartilage injury after impact at energy levels resulting in chondrocyte death and microstructural changes, but insufficient to produce macroscopic surface damage. METHODS: Bovine osteochondral cores underwent OCT imaging and were divided into a control with no impact or were subjected to low (0.175 J) or moderate (0.35 J) energy impact. Cores were reimaged with OCT after impact and the OCT signal intensity quantified. A ratio of the superficial to deep layer intensities was calculated and compared before and after impact. Chondrocyte viability was determined 1 day after impact followed by histology and polarized microscopy. RESULTS: Macroscopic changes to the articular surface were not observed after low and moderate impact. The OCT signal intensity ratio demonstrated a 27% increase (P = 0.006) after low impact and a 38% increase (P = 0.001) after moderate impact. Cell death increased by 150% (P < 0.001) and 200% (P < 0.001) after low and moderate energy impacts, respectively. When compared with unimpacted controls, both Mankin histology and David-Vaudey polarized microscopy scores increased (P = 0.036 and P = 0.002, respectively) after moderate energy impact. CONCLUSIONS: This study shows that OCT detects acute cartilage changes after impact injury at levels insufficient to cause visible damage to the articular surface but sufficient to cause chondrocyte death and microscopic matrix damage. This finding supports the use of OCT to detect microstructural subsurface cartilage damage that is poorly visualized with conventional imaging.

What is the role of intra-operative fluoroscopic measurements to determine tibial tunnel placement in anatomical anterior cruciate ligament reconstruction?

The hypothesis for this study was that intra-operative fluoroscopic measurements can be used to determine tibial tunnel placement during anatomic anterior cruciate ligament (ACL) reconstruction. The anteromedial (AM) and posterolateral (PL) bundle insertion sites were marked with a thermal device and measured in a consecutive cohort of 67 patients undergoing anatomical ACL reconstruction. For double bundle reconstruction, guide pins were passed in the center of the AM and PL tibial footprints. For single bundle (SB) reconstruction a guide wire was placed between the center of AM and PL footprints. Subsequently, the position of the centers of the AM and PL insertion sites were measured on standardized lateral intra-operative fluoroscopic images. The center for the AM bundle was found to be at 31% (range 20-42%) of the AP distance on the medial joint line and at 35% (range 23-42%) of the AP distance on the Amis and Jakob line. The center of the PL bundle was at 48% (range 37-59%) of the AP distance on the medial joint line and 48% (range 39-58%) of the AP distance on the Amis and Jakob line. The center of the tibial tunnel in the SB group (n = 15) was at 42 and 41% in relation to the medial joint line and the Amis and Jakob line, respectively. Because a significant anatomic variation exists between patients, the decision with respect to tunnel placement should not be merely based on intra-operative fluoroscopic images.

In vivo effects of single intra-articular injection of 0.5% bupivacaine on articular cartilage.

BACKGROUND: Single intra-articular injections of local anesthetics are commonly used clinically. Recent in vitro studies have demonstrated chondrotoxic effects of local anesthetics, with the greatest emphasis on bupivacaine toxicity. This in vivo study was conducted to determine whether a single intra-articular injection of 0.5% bupivacaine results in chondrocyte morbidity and rapid chondrolysis. METHODS: Forty-eight Sprague-Dawley rats received a 100-microL injection of sterile 0.9% saline solution (negative control) into one stifle joint and 100 microL of either preservative-free 0.5% bupivacaine (experimental group) or 0.6 mg/mL monoiodoacetate (positive control) into the contralateral joint. The rats were killed at one week, four weeks, twelve weeks, or six months. Live and dead cells were quantified with use of three-dimensional confocal reconstructions of fluorescent-stained tissues at standardized locations on the distal part of the femur. Histological findings were graded with use of a modified Mankin score, and cell density was quantified with use of custom image-analysis software. RESULTS: In the specimens injected with bupivacaine, the chondral surfaces remained intact as seen with gross and histological examination. No differences in superficial chondrocyte viability or modified Mankin scores were observed between the saline-solution and bupivacaine groups at any location or time point (p > 0.05). Quantitative histological analysis of the bupivacaine-treated knees at six months revealed an up to 50% reduction in chondrocyte density compared with that of the saline-solution-treated knees (p < or = 0.01). Monoiodoacetate injection resulted in death of up to 87% of the superficial chondrocyte cells at one week and chondrolysis at six months. Despite severe histological abnormalities by four weeks after monoiodoacetate injection, cartilage injury was not evident on gross inspection until six months. CONCLUSIONS: This in vivo study showing reduced chondrocyte density without cartilage tissue loss six months after a single intra-articular injection of 0.5% bupivacaine suggests bupivacaine toxicity. The effects of bupivacaine were milder than those of an injection of 0.6% monoiodoacetate, which resulted in chondrolysis over the same time period.

Animal models for cartilage regeneration and repair.

Articular cartilage injury and degeneration are leading causes of disability. Animal studies are critically important to developing effective treatments for cartilage injuries. This review focuses on the use of animal models for the study of the repair and regeneration of focal cartilage defects. Animals commonly used in cartilage repair studies include murine, lapine, canine, caprine, porcine, and equine models. There are advantages and disadvantages to each model. Small animal rodent and lapine models are cost effective, easy to house, and useful for pilot and proof-of-concept studies. The availability of transgenic and knockout mice provide opportunities for mechanistic in vivo study. Athymic mice and rats are additionally useful for evaluating the cartilage repair potential of human cells and tissues. Their small joint size, thin cartilage, and greater potential for intrinsic healing than humans, however, limit the translational value of small animal models. Large animal models with thicker articular cartilage permit study of both partial thickness and full thickness chondral repair, as well as osteochondral repair. Joint size and cartilage thickness for canine, caprine, and mini-pig models remain significantly smaller than that of humans. The repair and regeneration of chondral and osteochondral defects of size and volume comparable to that of clinically significant human lesions can be reliably studied primarily in equine models. While larger animals may more closely approximate the human clinical situation, they carry greater logistical, financial, and ethical considerations. A multifactorial analysis of each animal model should be carried out when planning in vivo studies. Ultimately, the scientific goals of the study will be critical in determining the appropriate animal model.

Progressive chondrocyte death after impact injury indicates a need for chondroprotective therapy.

BACKGROUND: Impact injury to articular cartilage can lead to posttraumatic osteoarthritis. HYPOTHESES: This study tests the hypotheses that (1) chondrocyte injury occurs after impact at energies insufficient to fracture the cartilage surface, and that (2) cartilage injury patterns vary with impact energy, time after injury, and cartilage thickness. STUDY DESIGN: Controlled laboratory study. METHODS: Fresh bovine osteochondral cores were randomly divided into 5 groups: (1) control, (2) 0.35 J, (3) 0.71 J, (4) 1.07 J, and (5) 1.43 J impact energies. Cores were subjected to computer-controlled impact loading and full-thickness sections were then prepared and incubated in Dulbecco's Modified Eagle's Medium/F12 at 37 degrees C. Adjacent sections were harvested 1 and 4 days after impact for viability staining and fluorescent imaging. The area of dead and living chondrocytes was quantified using custom image analysis software and reported as a percentage of total cartilage area. RESULTS: The highest impact energy fractured the cartilage in all cores (1.43 J, n = 17). Seventy-three percent and 64% of the osteochondral cores remained intact after lower energy impacts of 0.71 J and 1.07 J, respectively. At lower energy levels, fractured cores were thinner (P <.01) than those remaining intact. In cores remaining intact after impact injury, chondrocyte death increased with increasing impact energy (P <.05) and with greater time after impact (P <.05). A progressive increase in dead cells near the bone/cartilage interface and at the articular surface was observed. CONCLUSION: These data showing progressive chondrocyte death after impact injury at energies insufficient to fracture the cartilage surface demonstrate a potential need for early chondroprotective therapy. CLINICAL RELEVANCE: These data show that efforts to reduce chondrocyte morbidity after joint injury may be a useful strategy to delay or prevent the onset of posttraumatic osteoarthritis.

Treadmill running exercise results in the presence of numerous myofibroblasts in mouse patellar tendons.

Mechanical loading is known to alter tendon structure, but its cellular mechanisms are unclear. This study aimed to determine the effect of mechanical loading on tendon cells in vivo. C57BL/6J female mice were used in a treadmill running study. The treadmill running protocol consisted of treadmill training for 1 week, followed by sustained moderate running at 13 m/min for 50 min/day, 5 days/week, for 3 weeks. Immunohistochemical staining of tendon sections of mice after treadmill running revealed that numerous cells in the tendon section expressed alpha-SMA, whereas in the tendon sections of control mice, only a few cells exhibited weak alpha-SMA signals. Furthermore, mouse patellar tendon cells (MPTCs) derived from treadmill running mice were generally larger in culture, proliferated faster, expressed a higher level of alpha-SMA, and formed more abundant stress fibers compared to MPTCs from control mice. In addition, MPTCs from treadmill running mice generated larger traction forces (169 +/- 66.1 Pa) than those from control mice (102 +/- 34.2 Pa). Finally, cells from treadmill running mice produced higher levels of total collagen (516.4 +/- 92.7 microg/10,000 cells) than their counterparts (303.9 +/- 34.8 microg/10,000 cells). Thus, mechanical loading via treadmill running increased the presence of myofibroblasts in mouse patellar tendons. As myofibroblasts are activated fibroblasts, their presence in the tendon following treadmill running indicates that they actively repair and remodel tendon tissue under strenuous mechanical loading, leading to known changes in tendon structure.

A systematic review of the femoral origin and tibial insertion morphology of the ACL.

Transtibial single bundle anterior cruciate ligament (ACL) reconstruction has been the gold standard for several years. This technique often fails to restore native ACL femoral origin and tibial insertion anatomy of the ACL. Recently, there is a strong trend towards a more anatomical approach in single and double bundle ACL reconstruction. Using the anatomic double bundle structure of the ACL as a principle, the entirety of both tibial insertion and femoral origin of both bundles, the posterolateral and anteromedial, may be restored. Reflected by recent publications over the past two years, there is an increasing interest in the anatomy of the ACL. In the current study, a PubMed literature search was performed looking for measurements of the ACL femoral origin and tibial insertion. These studies show a large variability in the size and the anatomy of the femoral origin and tibial ACL insertion using different methods and specimens. The diversity of reported measurements makes clinical application of these data difficult at best. Thus, it is of paramount importance to understand the individual variations in size and shape of the ACL femoral origin and tibial ACL insertion. This study is a systematic review of the morphology of the ACL femoral origin and tibial insertion as reported in the literature.