An operative approach to address severe genu valgum deformity in the Ellis-van Creveld syndrome

BACKGROUND: The genu valgum deformity seen in the Ellis-van Creveld syndrome is one of the most severe angular deformities seen in any orthopaedic condition. It is likely a combination of a primary genetic-based dysplasia of the lateral portion of the tibial plateau combined with severe soft-tissue contractures that tether the tibia into valgus deformations. Progressive weight-bearing induces changes, accumulating with growth, acting on the initially distorted and valgus-angulated proximal tibia, worsening the deformity with skeletal maturation. The purpose of this study is to present a relatively large case series of a very rare condition that describes a surgical technique to correct the severe valgus deformity in the Ellis-van Creveld syndrome by combining extensive soft-tissue release with bony realignment. METHODS: 1. Complete proximal to distal surgical decompression of the peroneal nerve. 2. Radical release and mobilization of the severe quadriceps contracture and iliotibial band contracture. 3. Distal lateral hamstring lengthening/tenotomy and lateral collateral ligament release. 4. Proximal and distal realignment of the subluxed/dislocated patella, medial and lateral retinacular release, vastus medialis advancement, patellar chondroplasty, medial patellofemoral ligament plication, and distal patellar realignment by Roux-Goldthwait technique or patellar tendon transfer with tibial tubercle relocation. 5. Proximal tibial varus osteotomy with partial fibulectomy and anterior compartment release. 6. Occasionally, distal femoral osteotomy. RESULTS: In all cases, the combination of radical soft-tissue release, patellar realignment and bony osteotomy resulted in 10° or less of genu valgum at the time of surgical correction. Complications of surgery included three patients (five limbs) with knee stiffness that was successfully manipulated, one peroneal nerve palsy, one wound slough and hematoma requiring a skin graft, and one pseudoarthrosis requiring removal of hardware and repeat fixation. At last follow-up, radiographic correction of no more than 20° of genu valgum was maintained in all but four patients (four limbs). Two patients (three limbs) had or currently require revision surgery due to recurrence of the deformity. CONCLUSION: The operative approach presented in this study has resulted in correction of the severe genu valgum deformity in Ellis-van Creveld syndrome to 10° or less of genu valgum at the time of surgery. Although not an outcomes study, a correction of no more than 20° genu valgum has been maintained in many of the cases included in the study. Further clinical follow-up is still warranted. LEVEL OF EVIDENCE: IV

Onabotulinum Toxin Type a Injection Into the Triceps Unmasks Elbow Flexion in Infant Brachial Plexus Birth Palsy

Brachial plexus birth palsy (BPBP) is a neurologic injury that can result in mild to full paralysis of the affected upper extremity. In severe cases, nerve surgery is often performed before age 1 year. Several studies report gains in elbow flexion with onabotulinum toxin type A (OBTT-A) injections to the triceps; however, its use in infants is not widely reported. The purpose of this study is to present our experience using these injections before 6 months of age to therapeutically unmask elbow flexion and diagnostically guide surgical decision making. This is a retrospective observational cohort study. The cohort included infants with BPBP who received OBTT-A injection to the triceps before age 6 months. Indications for the injections include trace elbow flexion and palpable co-contraction of the biceps and triceps. Elbow flexion was evaluated using the Toronto Test score. Therapeutic success was defined as an increase in post-injection scores. These scores were then used diagnostically as an indication for surgery if the infant did not achieve full elbow flexion by 8 months. A treatment algorithm for OBTT-A triceps injection was developed based on all treatment options offered to infants with elbow flexion deficits seen in the clinic. Of the 12 infants that received OBTT-A triceps injections, 10 (83%) had improved Toronto test elbow flexion scores post-injection. Gains in elbow flexion once attained were maintained. Of the 9 OBTT-A infants with at least 2 years follow-up, 4 achieved full elbow flexion without surgery; the remainder after surgery. No complications with OBTT-A injections were noted and patients were followed on average 6 years. The average age at time of injection was 4 months (range: 2–5 months). Compared to other treatments given, OBTT-A infants tended to present with more elbow flexion than the 4 infants requiring immediate surgical intervention and less elbow flexion than the 16 infants treated conservatively. OBTT-A injection to the triceps in infants with BPBP before 6 months of age therapeutically improved elbow flexion and diagnostically guided surgical decisions when full elbow flexion was not achieved by 8 months of age with no known complications

An investigation to validate the equivalence of physes obtained from different anatomic regions in a single animal species: Implications for choosing experimental controls in clinical studies.

Control tissue in studies of various orthopedic pathologies is difficult to obtain and presumably equivalent biopsies from other anatomic sites have been utilized in its place. However, for growth plates, different anatomic regions are subject to dissimilar mechanical forces and produce disproportionate longitudinal growth. The purpose of this study was to compare gene expression and structure in normal physes from different anatomic regions within a single animal species to determine whether such physes were equivalent. Thirteen female New Zealand white rabbits (five 15-week-old and eight 19-week-old animals) were euthanized and physes harvested from their proximal and distal femurs and proximal tibiae. Harvested physes were divided into groups for histological, immunohistochemical (IHC), and reverse transcription-quantitative polymerase chain reaction analyses. All physes analyzed demonstrated no apparent differences in morphology or proteoglycan staining intensity on histological examination or in type II collagen presence determined by IHC study. Histomorphometric measures of physeal height as well as gene expression of type II collagen and aggrecan were found to be statistically significantly equivalent (p < 0.05) among the three different bones from the total number of rabbits. Summary data suggest that the structural similarities and statistical equivalence determined among the various physes investigated in the rabbit validate these tissues in this species for use as surrogate controls by which physeal abnormalities may be compared and characterized in the absence of otherwise normal control tissues. Other species may exhibit the same similarities and equivalence among different physes so that such tissues may serve in like manner as controls for assessing a variety of orthopedic conditions, including those occurring in humans

Serine Catabolism Feeds NADH when Respiration Is Impaired

NADH provides electrons for aerobic ATP production. In cells deprived of oxygen or with impaired electron transport chain activity, NADH accumulation can be toxic. To minimize such toxicity, elevated NADH inhibits the classical NADH-producing pathways: glucose, glutamine, and fat oxidation. Here, through deuterium-tracing studies in cultured cells and mice, we show that folate-dependent serine catabolism also produces substantial NADH. Strikingly, when respiration is impaired, serine catabolism through methylene tetrahydrofolate dehydrogenase (MTHFD2) becomes a major NADH source. In cells whose respiration is slowed by hypoxia, metformin, or genetic lesions, mitochondrial serine catabolism inhibition partially normalizes NADH levels and facilitates cell growth. In mice with engineered mitochondrial complex I deficiency (NDUSF4-/-), serine's contribution to NADH is elevated, and progression of spasticity is modestly slowed by pharmacological blockade of serine degradation. Thus, when respiration is impaired, serine catabolism contributes to toxic NADH accumulation