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How Much Ulnar Lengthening in Kids with HME-Related Radial Head Dislocation?

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.

Is the Tethering Juice Worth the Squeeze in AIS?

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

Treating Transitional Ankle Fractures: Best Evidence Yet

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
JBJS Editor-in-Chief

What’s New in Pediatric Orthopaedic Surgery 2020

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
—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

References

  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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.

Not All Modes in Multimodal Pain Management are Effective

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
JBJS Editor-in-Chief

Whence SCFE? More Hints Here

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
JBJS Editor-in-Chief

Mehta Casting for Early-Onset Scoliosis: Predictors of Success

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.”

Don’t Overlook Possible Osteoid Osteoma in Kids with Hip Pain

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.

What’s New in Pediatric Orthopaedics 2019

Every month, JBJS publishes a review of the most pertinent and impactful studies published in the orthopaedic literature during the previous year in one of 13 subspecialties. Click here for a collection of all OrthoBuzz subspecialty summaries.

This month, Kelly L. VanderHave, MD, co-author of the February 20, 2019 “What’s New in Pediatric Orthopaedics,” selected the five most compelling findings from among the more than 50 noteworthy studies summarized in the article.

Pediatric Trauma
—A before-and-after comparison found that, after implementation of a dedicated, weekday operating room reserved for pediatric trauma, length of stay for 5 common pediatric orthopaedic fractures was reduced by >5 hours. In addition, cost was reduced by about $1,200 per patient; complication rates improved slightly; frequency of after-hours surgery decreased by 48%; and wait times for surgery were significantly reduced.

—Forty-two patients with a distal radial buckle fracture received a removable wrist brace during an initial clinic visit, along with instructions to wear it for 3 to 4 weeks. No follow-up was scheduled, but the family was contacted at 1 week and at 5 to 10 months following treatment. No complications or refractures occurred; 100% of respondents said they would select the same treatment.1

Pediatric Sports Medicine
—Among a continuous cohort of 85 patients (mean age 13.9 years) who underwent primary ACL reconstruction (77% with open physes at time of surgery) and who were followed for a  minimum of 2 years, overall prevalence of a second ACL surgery was 32%, including 16 ACL graft ruptures and 11 contralateral ACL tears. A slower return to sport was found to be protective against a second ACL injury.

Infection and Scoliosis Surgery
—A preliminary study of 36 pediatric patients who underwent a total of 191 procedures for early-onset scoliosis found that the use of vancomycin powder during closure significantly decreased the rate of surgical site infection (13.8% per procedure in the control group versus 4.8% per procedure in the vancomycin group).

Clubfoot
—A retrospective review of >1,100 clubfeet that were presumed to be idiopathic upon presentation found that the condition in 112 feet (8.9%) was later determined to be associated with neurological, syndromic, chromosomal, or spinal abnormalities—and therefore nonidiopathic.2 The nonidiopathic group was less likely to have a good result at the 2- and 5-year follow-up, and more likely to require surgery. The authors conclude, however, that surgery is avoidable for most patients with nonidiopathic clubfoot.

References

  1. Kuba MHM, Izuka BH. One brace: one visit: treatment of pediatric distal radius fractures with a removable wrist brace and no follow-up visit. J Pediatr Orthop.2018 Jul;38(6):e338-42.
  2. Richards BS, Faulks S. Clubfoot infants initially thought to be idiopathic, but later found not to be. How do they do with nonoperative treatment?J Pediatr Orthop. 2017 Apr 10. [Epub ahead of print].

More Help Predicting Risk of Second SCFE

Up to 40% of kids who experience a slipped capital femoral epiphysis (SCFE) in one hip develop a slip in the contralateral hip. Recent research in pediatric orthopaedics has attempted to identify risk factors for a second SCFE in patients who have had a first. A retrospective study by Maranho et al. in the February 6, 2019 issue of JBJS provides additional evidence about one particular risk factor.

The authors radiographically measured the epiphyseal tilt, epiphyseal extension ratio, alpha angle, and epiphyseal angle of the uninvolved, contralateral hip among 318 patients (mean age of 12.4 years) who presented for treatment of a unilateral SCFE between 2000 and 2017. After adjusting for triradiate cartilage status, Maranho et al. found that, over a minimum follow-up of 18 months:

  • Increased posterior epiphyseal tilt was associated with an increased risk of contralateral SCFE, which corroborates recent findings. Specifically, an epiphyseal tilt of >10° corresponded to a 54% predicted probability of a contralateral slip in patients with open triradiate cartilage.
  • Increased epiphyseal extension around the metaphysis in the superior plane had a protective effect against a contralateral SCFE. For each 0.01 increase in superior epiphyseal extension ratio, the odds of a contralateral slip decreased by 6%.
  • The alpha angle and epiphyseal angle were not independently associated with a contralateral slip.

Clinically, the authors suggest that the tilt findings may be more useful than the extension-ratio findings, especially when it comes to the difficult decision around whether to perform prophylactic percutaneous pinning of the contralateral hip. They write that “prophylactic fixation may be discussed with the families of patients presenting with unilateral SCFE who have a tilt angle of >10°,” noting that this threshold “would result in a low proportion of patients undergoing unnecessary prophylactic pinning.” Maranho et al. are quick to add that even contralateral hips with epiphyseal tilt angles <10° are at risk of SCFE and should be closely monitored.

Read the JBJS Clinical Summary on SCFE.