Most orthopaedic spine surgeons and neurosurgeons have come to understand that syringomyelia plays a role in some cases of scoliosis, and that the spinal-cord condition may increase the risk of cord injury during deformity-correction surgery. In the August 19, 2020 issue of JBJS, Tan et al. investigate whether radiographic and clinical outcomes after 1-stage posterior spinal fusion to correct scoliosis secondary to syringomyelia differ between patients with syringomyelia related to Chiairi-I malformation (CIM) and those with idiopathic syringomyelia.
The short answer is “no.” Although researchers found larger preoperative syringeal parameters in the CIM group, up through 2 years after scoliosis-correction surgery, they detected no significant between-group differences in coronal/sagittal parameters or in scores from the 5 domains of the Scoliosis Research Society-22 questionnaire. Moreover, the preoperative neurological status and intraoperative neuromonitoring signals were similar in both groups.
In commenting on these findings, Kent A. Reinker, MD, points out that patients who had received preoperative neurological treatment for the syrinx were excluded from the study, so “the results … do not necessarily apply to patients who have had neurological intervention prior to scoliosis surgery.” He strongly recommends that all patients with a syrinx be referred to a neurosurgeon for evaluation prior to any scoliosis surgery, concluding that “a working partnership between orthopaedic surgeons and their neurological colleagues is important when assessing these patients.”
There is a wry saying in academic medicine that “nothing ruins good results like long-term follow-up.” But long-term follow-up helps us truly understand how our orthopaedic interventions affect patients. This is especially important with procedures on children, and the orthopaedic surgeons at the University of Iowa have been masterful with long-term outcome analysis in pediatric orthopaedics. They demonstrate that again in the August 5, 2020 issue of The Journal, as Scott et al. present their results comparing outcomes among 2 cohorts of patients who underwent treatment for developmental hip dislocations between the ages of 18 months and 5 years—and who were followed for a minimum of 40 years.
Seventy-eight hips in 58 patients underwent open reduction with Salter innominate osteotomy, and 58 hips in 45 patients were treated with closed reduction. At 48 years after reduction, 29 (50%) of the hips in the closed reduction cohort had undergone total hip arthroplasty (THA), compared to 24 (31%) of hips in the open reduction + osteotomy group. This rate of progression to THA nearly doubled compared to previously reported results at 40 years of follow-up, when 29% of hips in the closed reduction group and 14% of hips in the open reduction group had been replaced.
In addition, the authors found that patient age at the time of reduction and presence of unilateral or bilateral disease affected outcomes. Patients with bilateral disease who were treated at 18 months of age had a much lower rate of progression to THA when treated with closed reduction, compared to those treated with open reduction—but the opposite was true among patients with bilateral disease treated at 36 months of age. Treatment type and age did not seem to substantially affect hip survival among those with unilateral disease.
I commend the authors for their dedication to analyzing truly long-term follow-up data to help us understand treatment outcomes among late-diagnosed developmental hip dislocations in kids. Long-term follow-up may “ruin” good results, but it gives us more accurate and useful results. And, in this case, the findings reminded us how important it is to diagnose and treat developmental hip dislocations as early in a child’s life as possible.
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Lengthening the ulna is a common method of treating radial head dislocations due to hereditary multiple exostoses (HME) in pediatric patients, but the optimal amount of ulnar lengthening remains unclear. In the June 17, 2020 issue of JBJS, Huang et al. demonstrate that using the proportional ulnar length of 1.1 as a guide to ulnar lengthening can promote spontaneous correction of the radial shaft deformity. The authors arrived at the 1.1 proportion by measuring the normal lengths of the ulna and radius in 20 pediatric patients of different age groups.
Huang et al. then treated 30 forearms (average patient age of 7.4 years) that had a radial head dislocation associated with HME. They excised the osteochondroma around the physis of the distal part of the ulna prior to lengthening. They then pulled the radial head down to the plane of the ulnar coronoid process with a Kirschner wire and lengthened the ulna to predicted proportional length using a modified Ilizarov frame. The technique also facilitated lengthening of the soft tissues of the elbow.
At the time of frame removal, reduction of the dislocated radial head was achieved in 28 forearms (93%). Forearm function also improved markedly, as did radial bowing and the radioarticular angle. The actual ulnar lengthening distance in these patients was greater than the predicted lengthening using the proportional method, but that contributed to the spontaneous remodeling of the radial shaft deformity, and there were no instances of wrist impingement.
The authors conclude that this study demonstrates that, in this clinical scenario, the “proportional ulnar length is a safe and effective parameter to use as the ulnar lengthening reference value.” But they also note that the small number of patients and the average follow-up of 63 months in this study should be expanded in future research.
The tried-and-true treatment for progressive adolescent idiopathic scoliosis (AIS) is a posterior spinal fusion (PSF). However, for skeletally immature patients, there is increasing interest in motion-sparing growth modulation, specifically anterior vertebral body tethering (AVBT). Early reports on tethering looked promising, but the long-term prognosis remains fuzzy.
Newton et al. clarify this somewhat in the May 6, 2020 issue of JBJS. They retrospectively compared outcomes among a cohort of 23 AVBT patients followed for a mean of 3.4 years with those among a matched cohort of 26 PSF patients followed for a mean of 3.6 years. The groups were well-matched in terms of demographics and preoperative curve measurements, but the AVBT group was slightly less skeletally mature based on triradiate cartilage status and Sanders classification.
The authors found that both groups experienced significant postoperative curve correction, but the PSF group had significantly greater immediate correction of the main thoracic curve (78%) than the AVBT group (36%). Smaller immediate correction is to be expected in a growth-modulation procedure, which allows the spine to “grow straighter” over time with the tether. But at the final follow-up, the AVBT group had only a 43% curve correction versus 69% final follow-up correction in the PSF group. In addition, 9 revision procedures occurred in the AVBT group, versus none in the PSF group. Twelve patients (52%) in the AVBT group had evidence of broken tethers, with 3 of those patients undergoing revision surgery due to curve progression linked to tether breakage.
Overall, 12 of 23 patients in the AVBT group (52%) were deemed a “clinical success” at the end of the study (defined as a thoracic curve <35° without a need for a secondary fusion) while all 26 patients in the PSF group were deemed a clinical success. Anterior vertebral body tethering may have a role in the treatment of scoliosis in the growing spine, but the results to date, including these from Newton et al., lead me to question whether the tethering “juice” in its current form is worth the “squeeze.”
Matthew R. Schmitz, MD
JBJS Deputy Editor for Social Media
Transitional fractures of the ankle in adolescents are related to torsional injuries that occur around the time that the distal tibial physis begins to close. In recent years, treatment has moved toward screw fixation when the intra-articular fracture gap in Salter type III (Tillaux) and type IV (triplane) fractures is between 1 mm and 2 mm. The rationale for operative treatment has been that intra-articular fracture gaps should be completely reduced, particularly in younger patients, to limit the long-term risk of post-traumatic osteoarthroses. However, evidence supporting the wisdom of surgical intervention has been thin at best. (See Clinical Summary on Triplane Ankle Fractures.)
In the April 15, 2020 issue of The Journal, Lurie et al. report on a retrospective analysis of 34 patients with a triplane fracture and 23 patients with a Tillaux fracture, all of which had 2 mm to 5 mm of articular displacement. Among those 57 patients, 34 were treated with surgery and 23 with closed reduction and casting.
Based on regression analysis, nonoperative treatment, a larger intra-articular gap after closed reduction, and the presence of a grade-III complication were associated with worse functional outcomes at a mean follow-up of 4.5 years. Patients who were treated nonoperatively and had a gap ≤2.5 mm had significantly better functional scores than similar patients with a gap >2.5 mm. From this data, the authors conclude that “surgical management of these injuries likely conveys the greatest functional benefit when the intra-articular gap exceeds 2.5 mm.”
This study has the usual issues of treatment and detection bias inherent in retrospective reviews, and the measurement of fracture gaps, even with the CT scans these authors used, is not always reliable at this level of precision. Nevertheless, this data from Lurie et al. is the best we have to date to indicate that the so-called “2-mm rule” of nonoperative management of transitional ankle-fracture gaps ≤2 mm probably makes sense in most clinical situations.
Marc Swiontkowski, MD
Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in 13 subspecialties. Click here for a collection of OrthoBuzz summaries of these “What’s New” articles. This month, co-author Kelly Vanderhave, MD selected the 5 most clinically compelling findings from the more than 50 studies summarized in the February 19, 2020 “What’s New in Pediatric Orthopaedic Surgery.”
—ACL reconstruction in pediatric patients continues to receive research attention. A recent review of >560 cases showed that soft-tissue grafts used in this population were twice as likely to fail (13%) as patellar tendon grafts (6%) (p <0.001).1
Septic Arthritis of the Hip
—A multicenter study identified the following independent risk factors for a repeat surgical procedure after initial arthrotomy for septic arthritis of the hip: presenting CRP of >10 mg/dL and ESR of >40 mm/hr, and the presence of osteomyelitis and MRSA.2
Adolescent Idiopathic Scoliosis
—A minimum 20-year follow-up of a cohort study evaluating 180 patients after observation, bracing, or surgical management of adolescent idiopathic scoliosis found the following:
- In the observation cohort, 5 of 36 patients underwent a scoliosis surgical procedure as an adult.
- In the bracing cohort, only 1 of 41 patients required an additional spinal surgical procedure.
- In the surgical cohort, 7 of 103 patients required a revision surgical procedure.
At a mean follow-up of 30 years, there were no significant differences in patient-reported outcomes between the 3 cohorts.3
Infection after Spinal Deformity Surgery
—A retrospective study of >600 pediatric patients who underwent spinal deformity surgery identified 2 independent risk factors among 11 cases of deep surgical site infection that occurred >3 months after the procedure:
- Nonidiopathic scoliosis (e.g., neuromuscular, congenital, and syndromic etiologies)
- High volume of crystalloid administered during surgery (mean of 3.3 ±1.2 L in the group with surgical site infections vs 2.4 ±1.0 L in the infected group)
Redosing antibiotics intraoperatively after 3 hours did not significantly influence the risk of infection.4
Hip Dislocations in Infants with CP
—Among 11 patients (15 hips) with spastic cerebral palsy whose preoperative mean acetabular index was 29°, surgical hip reconstruction (a combination of open reduction, adductor tenotomy, femoral osteotomy, and/or pelvic osteotomy) yielded the following results at a mean follow-up of 40 months:
- Mean migration index of 7%
- Mean acetabular index of 22°
- No instances of osteonecrosis
- 90% achievement and maintenance of hip reduction in those who underwent open reduction with or without pelvic or femoral osteotomy.5
- Ho B, Edmonds EW, Chambers HG, Bastrom TP, Pennock AT. Risk factors for early ACL reconstruction failure in pediatric and adolescent patients: a review of 561 cases. J Pediatr Orthop. 2018 Aug;38(7):388-92.
- Murphy RF, Plumblee L, Barfield WB, Murphy JS, Fuerstenau N, Spence DD, Kelly DM, Dow MA, Mooney JF 3rd. Septic arthritis of the hip-risk factors associated with secondary surgery. J Am Acad Orthop Surg. 2019 May 1;27(9):321-6.
- Larson AN, Baky F, Ashraf A, Baghdadi YM, Treder V, Polly DW Jr, Yaszemski MJ. Minimum 20-year health-related quality of life and surgical rates after the treatment of adolescent idiopathic scoliosis. Spine Deform. 2019 May;7(3):417-27.
- Du JY, Poe-Kochert C, Thompson GH, Son-Hing JP, Hardesty CK, Mistovich RJ. Risk factors for early infection in pediatric spinal deformity surgery: a multivariate analysis. Spine Deform. 2019 May;7(3):410-6.
- Refakis CA, Baldwin KD, Spiegel DA, Sankar WN. Treatment of the dislocated hip in infants with spasticity. J Pediatr Orthop. 2018 Aug;38(7):345-9.
The public health crisis attributed to opioids has placed increasing emphasis on other approaches to pain management, both pharmacologic and nonpharmacologic. Although some people find the term “multimodal pain management” to be ambiguous when used in clinical research or patient care, it emphasizes the need for a broader (and multidisciplinary) approach to pain management.
On the pharmacologic side, pregabalin has been found to be a variably effective adjunctive analgesic in research involving joint arthroplasty. However, its use in adolescents and children has not been adequately explored. In the February 5, 2020 issue of The Journal, Helenius et al. investigate the impact of pregabalin on total opioid consumption and pain scores in a randomized, placebo-controlled trial of 63 adolescents undergoing posterior instrumented spinal-fusion procedures. These operations are quite invasive and often result in ICU admission because of the amount of narcotics required. In this study, induction and maintenance of anesthesia and mobilization protocols were standardized for patients in both the pregabalin and placebo groups, and the authors precisely measured opioid consumption during the first 48 hours after surgery with data from patient-controlled anesthesia systems.
According to the findings from this adequately powered trial, adjunctive pregabalin did not have a positive impact on opioid consumption or postoperative pain scores. Despite these negative findings, it is my hope that this drug and others being investigated as adjunctive “modes” in multimodal pain management will be subjected to similarly designed trials, so we can accurately determine which agents work best in limiting opioid utilization.
Marc Swiontkowski, MD
Pediatric orthopaedists have long been searching for anatomic, mechanical, and metabolic causes of slipped capital femoral epiphysis (SCFE). Adolescent obesity has been a recognized SCFE risk factor for 50 years. (Interestingly, high BMI is a consistent risk factor in males, but females who experience SCFE are often thin.) Possible racial risk factors have been examined as well, with no clear conclusions.
Because the incidence of SCFE is relatively low (1 in 10,000 children according to this JBJS Clinical Summary) and the risk of bilaterality is high (in the range of 30% to 40%), it seems likely that anatomic risk factors are at play. In the January 2, 2020 issue of The Journal, Novias et al. home in on the 3-D anatomy of the epiphyseal tubercle (a small, round protuberance thought to stabilize the epiphysis) and peripheral “cupping” of the epiphysis in patients with and without SCFE.
They found a smaller epiphyseal tubercle and more extensive epiphyseal cupping in patients with SCFE compared with normal hips. The authors encourage further investigation of the first finding to determine whether smaller tubercles are a consequence of the slip process or an anatomic variant that predisposes the epiphysis to slip.
A major strength of this study is that all measurements were made by a single observer blinded to the diagnosis of SCFE and other potentially confounding clinical and demographic data. Also, the measurement processes used in this study have been previously validated.
Investigation into the anatomic features of this disease should continue, along with development of minimally invasive, safe, and inexpensive ways to screen for possible anatomic risk factors. The most pertinent clinical goals are to continue evolving minimally invasive methods of epiphyseal stabilization to prevent and/or treat SCFE and to more accurately identify hips at risk of SCFE.
Marc Swiontkowski, MD
The treatment of early-onset scoliosis with Mehta casting is a long process, but if successful, it can delay or obviate the need for surgery. In the September 4, 2019 issue of JBJS, Fedorak et al. examine outcomes among 38 patients (mean age of 24 ± 15 months at time of first casting) who were treated with Mehta casting and followed for a mean of 8 ± 2 years. The retrospective review identified differences between patients who had a Cobb angle ≤15° (improvement group) at the most recent follow-up and those who had a Cobb angle of >15° (no-improvement group).
Forty-nine percent of children had achieved and maintained scoliosis of ≤15° at the time of the most recent follow-up, and 73% were improved by at least 20°, although 3 children ended up relapsing after meeting recommended criteria for discontinuation of casting. There was no significant difference in thoracic-height gain between the groups, demonstrating that even when scoliosis was not corrected, growth was maintained during cast treatment.
Patients in the improvement group had a mean age of 18.9 ± 12 months and scoliosis of 48.2° ± 14° at the initiation of treatment. Here are 3 additional factors that were associated with a greater likelihood of scoliosis of ≤15°:
- A lower pre-treatment Cobb angle and traction Cobb angle
- A smaller rib-vertebral angle difference on first-in-cast radiograph
- A lower Cobb angle on first-in-cast radiograph
The authors note that although this study analyzed longer-term follow-up data than most other similar investigations, “treatment of early-onset scoliosis is not truly finished until skeletal maturity has been reached.”
Orthopaedists are seeing an increasing number of active, young patients with hip pain. A study by May et al. in the March 20, 2019 issue of The Journal of Bone & Joint Surgery strongly suggests that osteoid osteoma (OO)—a small, benign tumor characterized by dense sclerotic bone tissue—should not be overlooked in the differential diagnosis when working up these patients.
The authors identified and reviewed the records of 50 children and adolescents (mean age of 12.4 years) at their tertiary-care pediatric center who had received a diagnosis of OO within or around the hip between 2003 and 2015. Nighttime hip and/or thigh pain (90%) and symptom relief with NSAIDs (88%) were common clinical findings.
Sclerosis/cortical thickening was visible in 58% of the radiographs. Perilesional edema and a radiolucent nidus was found on all 43 of the available CT scans, leading the authors to conclude that “CT scans provide definitive diagnosis” of OO.
Unfortunately, 46% of these patients initially received an alternative diagnosis, the most common of which was femoroacetabular impingement (FAI), and a delay in diagnosis of >6 months occurred in 43% of patients. The authors note that concerns regarding radiation exposure have led some clinicians to order MRI rather than CT when evaluating pediatric hip disorders, but this study found that identifying an OO nidus with MRI was not as accurate as doing so with CT.
Regarding treatment, among the 41 patients who ultimately underwent percutaneous radiofrequency ablation (RFA) to treat OO, 93% achieved complete post-RFA symptom resolution. Complications from RFA occurred in 7% of patients who underwent the procedure.