Is Proximal Fibula Epiphysiodesis Necessary When Performing a Proximal Tibial Epiphysiodesis?

BACKGROUND: Controversy exists regarding the need for proximal fibular epiphysiodesis in conjunction with proximal tibial epiphysiodesis to prevent relative overgrowth of the fibula. The purpose of this study was to determine the incidence of relative fibular overgrowth in patients who had undergone proximal tibial epiphysiodesis with or without proximal fibular epiphysiodesis to manage leg-length discrepancy. METHODS: We identified patients who had undergone proximal tibial epiphysiodesis, with or without concomitant fibular epiphysiodesis, followed to skeletal maturity, and with adequate scanograms to measure tibial and fibular lengths. We assessed tibial and fibular lengths, ratios, and distances between the tibia and fibula proximally and distally preoperatively and at skeletal maturity, and obvious radiographic proximal migration of the fibular head. RESULTS: A total of 234 patients met inclusion criteria, including 112 girls and 122 boys. In total, 179 patients had undergone concomitant fibular epiphysiodesis, and 55 had not. The fibular epiphysiodesis group was significantly younger preoperatively than the nonfibular epiphysiodesis group (average: 12.3 vs. 13.6 y), which accounted for most of the preoperative differences noted between the groups. Within the subset of younger patients (≥2 y of growth remaining at the time of epiphysiodesis), there were statistically significant differences between those with or without fibular epiphysiodesis at skeletal maturity in the proximal tibial-fibular distance (P<0.01) and the tibia:fibula ratio (0.96±0.02 vs. 0.98±0.02; P<0.02), but not in the distal tibial-fibular distance (P=0.46). Obvious fibular head proximal migration was noted in 10 patients, including 5/179 with concomitant proximal fibular epiphysiodesis, and 5/55 without (P<0.01). No patient was recorded as symptomatic with radiographic overgrowth, and no peroneal nerve injury occurred in any patient in this cohort. CONCLUSIONS: On the basis of this study, concomitant proximal fibular epiphysiodesis does not appear to be necessary in patients with 2 years or less of growth remaining, nor does it unequivocally prevent fibular head overgrowth. While the tibia:fibula ratio was quite consistent in general, there were individuals with relative fibular head prominence for whom fibular epiphysiodesis may be appropriate, particularly in relatively immature patients. LEVEL OF EVIDENCE: Level III-retrospective comparative study.

Quengel Casting for the Management of Pediatric Knee Flexion Contractures: A 26-Year Single Institution Experience.

BACKGROUND: Quengel casting was introduced in 1922 for nonsurgical treatment of knee flexion contractures (KFC) associated with hemophilic arthropathy. It consists of an extension-desubluxation hinge fixed to a cast allowing for gradual correction of a flexion deformity while preventing posterior tibial subluxation. The purpose of this study is to report 1 center's experience with this technique for the treatment of pediatric KFC. METHODS: A retrospective review was conducted over a 26-year period. All patients with KFC treated with Quengel casting were included. Demographic data, associated medical conditions, adjunctive soft tissue releases, complications, and the need for late surgical intervention were recorded. Tibiofemoral angle measurements in maximal extension were recorded at initiation and termination of casting, 1-year follow-up, and final follow-up. Success was defined as no symptomatic recurrence of KFC or need for subsequent surgery. RESULTS: Eighteen patients (26 knees) were treated for KFC with Quengel casting. Average age at initiation of casting was 8.1 years with average follow-up of 59.9 months. Fifteen knees (58%) underwent soft tissue releases before casting. An average of 1.5 casts per knee were applied over an average of 23.9 days. Average KFC before casting was 50.6 degrees (range, 15 to 100 degrees) which improved to 5.96 degrees (0 to 40 degrees) at cast removal (P<0.00001). Sixteen patients (22 knees) had 1-year follow-up or failed casting before 1 year. Of these, 11 knees (50%) had a successful outcome. Residual KFC of those treated successfully was 6.8 degrees (range, 0 to 30 degrees) at 1 year and 8.2 degrees (range, 0 to 30 degrees) at final follow-up, averaging 71.4 months (P=0.81). Of the 11 knees deemed failures, all had recurrence of deformity within an average of 1 year from cast removal. Surgical release before Quengel casting did not improve the chances for success (P=0.09). CONCLUSIONS: Quengel casting can improve pediatric KFC an average of 44.2 degrees with minimal complications. Although 50% of treated patients will demonstrate significant recurrence or need later surgery, the majority of those treated successfully have durable results at intermediate term follow-up. LEVEL OF EVIDENCE: Level IV-therapeutic study.

Synthesis and properties of lanthanide ruthenium(III) oxide perovskites.

An extensive series of new LnRuO3 perovskites has been synthesized at high pressure. These ruthenium(III)-based oxides are ruthenium deficient, and high-pressure samples have compositions close to LnRu(0.9)O3. These phases stabilize ruthenium(III) which is very unusual in oxides. X-ray and neutron powder diffraction studies show that the materials adopt orthorhombic perovskite superstructures in which the RuO6 octahedra are tetragonally compressed. These distortions, and the Mott insulator properties of the materials, are driven by strong spin-orbit coupling.

Lower-Extremity Segment-Length Prediction Accuracy of the Sanders Multiplier, Paley Multiplier, and White-Menelaus Formula.

BACKGROUND: Several methods are available to estimate leg lengths at maturity to facilitate the determination of timing of epiphysiodesis. We compared the Paley multiplier, Sanders multiplier, and White-Menelaus methods in an epiphysiodesis-aged cohort. We assessed intra- and interrater reliability for Sanders skeletal stages and Greulich and Pyle atlas skeletal age. METHODS: Actual growth was recorded in healthy, unoperated femoral and tibial segments from an epiphysiodesis database. The predicted and actual lengths were compared with use of the Paley multiplier and White-Menelaus methods, Greulich and Pyle skeletal age, and the Sanders multiplier using Sanders stages. Intra- and interrater reliability were assessed in a separate group of 76 skeletal age films. RESULTS: The cohort included 148 femora and 195 tibiae in 197 patients. Femoral length at maturity was slightly underestimated by the Sanders multiplier and staging, was overestimated by the Paley multiplier and skeletal age, and was most accurately predicted with use of the White-Menelaus formula and skeletal age. All methods overestimated tibial length at maturity. The whole-leg prediction accuracy of the Sanders multiplier and White-Menelaus formula were comparable and were more accurate than that of the Paley multiplier. For Sanders skeletal staging, the interrater reliability varied from 0.86 to 0.88 and the intrarater reliability varied from 0.87 to 0.96. For Greulich and Pyle skeletal age, the interrater reliability varied from 0.87 to 0.89 and the intrarater reliability varied from 0.91 to 0.95. CONCLUSIONS: Use of the Sanders multiplier and skeletal stages was more accurate than the Paley multiplier and skeletal age in this cohort. Use of the White-Menelaus formula and skeletal age was slightly more accurate in predicting femoral length and slightly less accurate in predicting tibial length compared with the Sanders multiplier. Intra- and interrater reliability were similar between Sanders skeletal stages and Greulich and Pyle atlas skeletal age. The White-Menelaus formula and skeletal age was the recommended method for predicting lower-extremity segment lengths at maturity and epiphysiodesis effect. Although easier to recall without referencing an atlas and not sex-specific, Sanders skeletal staging does not correspond directly to years of growth remaining, and thus cannot be used with the White-Menelaus formula. CLINICAL RELEVANCE: The Greulich and Pyle atlas to determine skeletal age and the White-Menelaus formula to determine growth remaining are reliable predictors of epiphysiodesis effect in the lower extremities.

Direct solid-state synthesis at high pressures of new mixed-metal oxynitrides: RZrO(2)N (R = Pr, Nd, and Sm).

New oxynitrides of RZrO(2)N (R = Pr, Nd, and Sm) have been synthesized via a direct solid-state reaction of R(2)O(3) with Zr(2)ON(2) at 1200-1500 degrees C under 2-3 GPa pressure. Powder X-ray diffraction shows that all three phases adopt an orthorhombic Pnma perovskite superstructure [a = 5.8537(1) A, b = 8.1707(1) A, and c = 5.7093(1) A for NdZrO(2)N] and the structural distortion increases with decreasing R(3+) ionic radius. This method may enable new mixed-metal oxynitrides to be synthesized without the use of nitriding gas atmospheres.

Large coupled magnetoresponses in EuNbO2N.

We have explored a new strategy to discover materials with large resistive or capacitive responses to magnetic fields by synthesizing EuMO2N (M = Nb, Ta) perovskites that combine ferromagnetic order of S = 7/2 Eu2+ spins with possible off-center distortions of the d0 M5+ cations enhanced by covalent bonding to N. EuNbO2N shows colossal magnetoresistances at low temperatures and a giant magnetocapacitance. However, the latter response originates from a microstructural effect rather than an intrinsic multiferroism.

Anion order in perovskite oxynitrides.

Transition-metal oxynitrides with perovskite-type structures are an emerging class of materials with optical, photocatalytic, dielectric and magnetoresistive properties that may be sensitive to oxide-nitride order, but the anion-ordering principles were unclear. Here we report an investigation of the representative compounds SrMO(2)N (M = Nb, Ta) using neutron and electron diffraction. This revealed a robust 1O/2(O(0.5)N(0.5)) partial anion order (up to at least 750 °C in the apparently cubic high-temperature phases) that directs the rotations of MO(4)N(2) octahedra in the room-temperature superstructure. The anion distribution is consistent with local cis-ordering of the two nitrides in each octahedron driven by covalency, which results in disordered zigzag M-N chains in planes within the perovskite lattice. Local structures for the full range of oxynitride perovskites are predicted and a future challenge is to tune properties by controlling the order and dimensionality of the anion chains and networks.

Metal-insulator transition and orbital order in PbRuO3.

Anomalous low temperature electronic and structural behavior has been discovered in PbRuO3. The structure [space group Pnma, a=5.563 14(1), b=7.864 68(1), c=5.614 30(1) A] and metallic conductivity at 290 K are similar to those of SrRuO3 and other ruthenate perovskites, but a sharp metal-insulator transition at which the resistivity increases by 4 orders of magnitude is discovered at 90 K. This is accompanied by a first-order structural transition to an Imma phase [a=5.569 62(1), b=7.745 50(1), c=5.662 08(1) A at 25 K] that shows a coupling of Ru4+ 4d orbital order to distortions from Pb2+ 6s6p orbital hybridization. The Pnma to Imma transition is an unconventional reversal of the group-subgroup symmetry relationship. No long range magnetic order is evident down to 1.5 K. Calculations show that Pb 6s6p and Ru 4d orbital hybridization and strong spin-orbit coupling are significant.

Subtle structural variation in copper metal-organic frameworks: syntheses, structures, magnetic properties and catalytic behaviour.

Two new copper metal-organic frameworks containing 5-nitro-1,3-benzenedicarboxylate (5-nbdc) have been prepared from the reaction between Cu(NO(3))(2).3H(2)O and H(2)(5-nbdc) in DMF at different temperatures. Single crystal X-ray structures of {[Cu(2)(5-nbdc)(2)(DMF)(2)].2DMF}(infinity) () and {[Cu(2)(5-nbdc)(2)(DMF)(2)].3(1/3)DMF}(infinity) () revealed similar sheet structures, containing triangular and hexagonal pores, but differences in the stacking of the sheets. Magnetic measurements on and are consistent with antiferromagnetic dimers containing a small quantity of paramagnetic impurity. The desolvated forms of and were applied as Lewis acid catalysts in the acetylation of methyl 4-hydroxybenzoate. When the reaction between Cu(NO(3))(2).3H(2)O and H(2)(5-nbdc) was carried out in a mixture of DMF and water, the reaction gave metallomacrocycles of formula [Cu(6)(5-nbdc)(6)(H(2)O)(12)(DMF)(6)] (). These assemble through hydrogen-bonding interactions to form a gross structure in which the macrocycle pores align into channels. The reaction between Cu(NO(3))(2).3H(2)O and 5-methylsulfanylmethyl-1,3-benzenedicarboxylic acid, H(2)(5-msbdc), in DMF-water gave {[Cu(2)(5-msbdc)(2)(OH(2))(2)].3DMF}(infinity) (), which contains similar sheets to those in and , whereas the reaction with 5-amino-1,3-benzenedicarboxylic acid, H(2)(5-abdc), gave {[Cu(2)(5-abdc)(2)(DMF)(2)]}(infinity) (), which has a previously reported network based on sheets containing rhombohedral pores. The reaction between Cu(NO(3))(2).3H(2)O and 2-methoxy-1,3-benzenedicarboxylic acid, H(2)(2-mbdc), in DMF gave [Cu(2)(2-mbdc)(2)(DMF)(2)] (). The presence of the substituent in the 2-position removes the co-planarity of the carboxylate groups, and the sheet structure adopted by contains rhomboidal pores.

High pressure synthesis of late rare earth RFeAs(O,F) superconductors; R = Tb and Dy.

New TbFeAs(O,F) and DyFeAs(O,F) superconductors with critical temperatures T(c) = 46 and 45 K and very high critical fields, >or=100 T, have been prepared at 1100-1150 degrees C and 10-12 GPa, demonstrating that high pressure may be used to synthesise late rare earth derivatives of the recently reported RFeAs(O,F) (R = La-Nd, Sm, Gd) high temperature superconductors.