Hui Taek Kim

Chronic radial head dislocation in children, Part 2: results of open treatment and factors affecting final outcome.

Fifteen elbows (3 congenital, 12 traumatic) in 14 children (mean age 9.5 years) with chronic radial head dislocation for at least 3 months (range 3–180 months) underwent radial head-sparing reconstructive surgery and were followed up at an average of 43.5 months postoperatively (range 12–105 months). At follow-up, the patients were evaluated radiographically and clinically using range-of-motion measurements and an elbow performance score based on four parameters (deformity, pain, motion, function). Ten cases had excellent results, two had good results, two had fair results, and one case had poor results. Scores at follow-up were evaluated with seven preoperative factors. Among those, the degree of preoperative carrying angle asymmetry associated with flexion contracture correlated significantly with the elbow scores. The most common complication was loss of pronation. The authors advocate radial head reduction and reconstruction in chronic radial head dislocations in children after obtaining informed consent from patient and parents.

Chronic radial head dislocation in children, part 1 : pathologic changes preventing stable reduction and surgical correction

The pathologic changes in 15 elbows of 14 children (2 bilateral congenital, 12 unilateral posttraumatic, mean age 9.5 years) with radial head dislocation unreduced for at least 3 months (range 3–180 months) and their open treatment were reviewed. Common dysplastic changes observed in both congenital and posttraumatic groups included large deformed radial heads, slender radial necks, and ulnar bowing. Changes were bilateral and symmetrical in the congenital group. In traumatic dislocations, patients with more severe deformities had longer delays from time of injury to time of reduction. Persistent pain, limitation of motion, and deformity were unacceptable symptoms to both patients and their parents, prompting surgical intervention. To produce a smooth rotational arc for the radius and maintain it in stable reduction, restoration of the congruency of the capitello-radioulnar joint and correction of the various dysplastic changes were mandatory during open reduction.

In vivo study of chitosan-natural nano hydroxyapatite scaffolds for bone tissue regeneration

Significant development has been achieved with bioceramics and biopolymer scaffolds in the construction of artificial bone. In the present study, we have developed and compared chitosan-micro hydroxyapatite (chitosan-mHA) and chitosan-nano hydroxyapatite (chitosan-nHA) scaffolds as bone graft substitutes. The biocompatibility and cell proliferation of the prepared scaffolds were checked with preosteoblast (MC3T3-E1) cells. Total Volume (TV), bone volume (BV), bone surface (BS), trabecular thickness (Tb.Th), trabecular number (Tb.N) and trabecular separation (Tb.Sp) were found to be higher in chitosan-nHA than chitosan-mHA scaffold. Hence, we suggest that chitosan-nHA scaffold could be a promising biomaterial for bone tissue engineering.

Avascular necrosis after fracture-separation of the distal end of the humerus in children.

Fracture-separation of the distal end of the humerus in children has been reported infrequently, and may be misdiagnosed as a fracture of the condyle or a traumatic dislocation of the elbow. We discuss eight cases of a seldom reported complication following fracture-separation of the distal end of the humerus. This complication consists of dissolution of the trochlea within three to six weeks postinjury and a defect of the medial or central part of the condyle that develops later. The fractures were severely displaced fracture-separation of the distal end of the humerus with large medial or lateral metaphyseal fragment, but initially misdiagnosed as a fracture of the medial, lateral condyle or a traumatic dislocation of the elbow in six of eight cases. We performed open reduction in six cases because of initial misdiagnosis or because of difficulty in satisfactory closed reduction. We speculated that this complication is due to avascular necrosis of the distal end of the humerus, and that fracture-separation of the distal end of the humerus is more common than reported.

Trochlear deformity occurring after distal humeral fractures: magnetic resonance imaging and its natural progression.

Eighteen children (mean age 50.7 months) with trochlear deformities occurring after and related to distal humeral fractures (12 Salter-Harris type 2, 5 supracondylar, 1 Salter-Harris type 4) were evaluated with serial radiographs. The carrying angle and range of motion were measured throughout the follow-up period (up to 13 years after trauma) after definitive treatment. Bony defects on the medial (17 patients) and central (1 patient) regions of the trochlea were observed at a mean of 3.4 months after the trauma. They also persisted up to 4 to 7 years (latest follow-up in an intermediate follow-up group) and eventually reossified by skeletal maturity (in a long-term follow-up group). Magnetic resonance imaging was performed on eight patients after a mean of 1.9 years from injury. Low signal intensity on T2 indicative of cartilage necrosis and an intact articular surface were found. Cubitus varus deformity, which developed in almost all patients, was observed to be nonprogressive after 3 to 4 years but persisted until maturity. Limitation of motion and late neuropathy were not seen.

Interaction of stem cells with nano hydroxyapatite-fucoidan bionanocomposites for bone tissue regeneration.

The combination of bioceramics with biopolymers are playing major role in the construction of artificial bone. Hydroxyapatite (HA) has been extensively studied as a material in bone repair and replacement in last two decades. In the present study, we have prepared the hydroxyapatite-fucoidan (HA-Fucoidan) nanocomposites by in situ chemical method and biologically characterized them for bone graft substitute. Biological results inferred that mineralization effect of HA-F nanocomposites shows significant enhancement compared to HA in adipose derived stem cell (ADSC). It may be due to the addition of fucoidan in the nanocomposites. The important gene expression such as osteocalcin, osteopontin, collagen and runx-2 were checked using ADSC with HA and HA-fucoidan nanocomposites and the results show that the enhancements were found at 7th day. Furthermore, we have performed in vivo study of HA-fucoidan nanocomposites with rabbit model and a slight amount of bone formation was observed in HA-fucoidan nanocomposites. Herewith, we suggest that HA-fucoidan nanocomposites will be good biomaterials for bone repair/replacement in future.

Early Results of One-Stage Correction for Hip Instability in Cerebral Palsy

Background We evaluated the clinical and radiological results of one-stage correction for cerebral palsy patients. Methods We reviewed clinical outcomes and radiologic indices of 32 dysplastic hips in 23 children with cerebral palsy (13 males, 10 females; mean age, 8.6 years). Ten hips had dislocation, while 22 had subluxation. Preoperative Gross Motor Function Classification System (GMFCS) scores of the patients were as follows; level V (13 patients), level IV (9), and level III (1). Acetabular deficiency was anterior in 5 hips, superolateral in 7, posterior in 11 and mixed in 9, according to 3 dimensional computed tomography. The combined surgery included open reduction of the femoral head, release of contracted muscles, femoral shortening varus derotation osteotomy and the modified Dega osteotomy. Hip range of motion, GMFCS level, acetabular index, center-edge angle and migration percentage were measured before and after surgery. The mean follow-up period was 28.1 months. Results Hip abduction (median, 40°), sitting comfort and GMFCS level were improved after surgery, and pain was decreased. There were two cases of femoral head avascular necrosis, but no infection, nonunion, resubluxation or redislocation. All radiologic indices showed improvement after surgery. Conclusions A single event multilevel surgery including soft tissue, pelvic and femoral side correction is effective in treating spastic dislocation of the hip in cerebral palsy.

A Graphic Overlay Method for Selection of Osteotomy Site in Chronic Radial Head Dislocation: An Evaluation of 3D-printed Bone Models.

Purpose: Three-dimensional (3D) computed tomography imaging is now being used to generate 3D models for planning orthopaedic surgery, but the process remains time consuming and expensive. For chronic radial head dislocation, we have designed a graphic overlay approach that employs selected 3D computer images and widely available software to simplify the process of osteotomy site selection. Methods: We studied 5 patients (2 traumatic and 3 congenital) with unilateral radial head dislocation. These patients were treated with surgery based on traditional radiographs, but they also had full sets of 3D CT imaging done both before and after their surgery: these 3D CT images form the basis for this study. From the 3D CT images, each patient generated 3 sets of 3D-printed bone models: 2 copies of the preoperative condition, and 1 copy of the postoperative condition. One set of the preoperative models was then actually osteotomized and fixed in the manner suggested by our graphic technique. Arcs of rotation of the 3 sets of 3D-printed bone models were then compared. Results: Arcs of rotation of the 3 groups of bone models were significantly different, with the models osteotomized accordingly to our graphic technique having the widest arcs. Conclusions: For chronic radial head dislocation, our graphic overlay approach simplifies the selection of the osteotomy site(s). Three-dimensional-printed bone models suggest that this approach could improve range of motion of the forearm in actual surgical practice. Level of Evidence: Level IV—therapeutic study.

Z-lengthening of the Achilles tendon with transverse skin incision.

Background The risk of various complications after Achilles tendon lengthening is mainly related to the length of surgical exposure and the lengthening method. A comprehensive technique to minimize the complications is required. Methods The treatment of Achilles tendon tightness in 57 patients (95 ankles) were performed by using a short transverse incision on a skin crease of the heel and by Z-lengthening of the tendon. In the severe cases, two or three transverse incisions were required for greater lengthening of the tendon, and a serial cast or Ilizarov apparatus was applied for the gradual correction. The results of these 95 ankles were compared to those of 18 ankles, which underwent percutaneous sliding lengthening, and to the 19 ankles, which received Z-lengthening with a medial longitudinal incision. Results The functional and cosmetic satisfaction was achieved among those who underwent the tendon lengthening with the new technique. The mean American Orthopaedic Foot & Ankle Society (AOFAS) score improved from 56.1 to 81.8. The second operations to correct recurrence were performed in the two cerebral palsy patients. Conclusions The new technique has a low rate of complications such as scarring, adhesion, total transection, excessive lengthening, and recurrence of shortening. The excellent cosmesis and the short operation time are the additional advantages.

The Fate of DDH Hips Showing Cartilaginous or Fibrous Tissue-filled Joint Spaces Following Primary Reduction.

Background: Because the use of magnetic resonance imaging is still not universal for the patients with developmental dysplasia of the hip patients, orthopaedists do not generally distinguish widened joint spaces which are “empty” after primary treatment (and therefore still reducible), from those which are filled and much more difficult to treat. To date no studies have focused on the latter hips. We treated and observed the outcomes for 19 hips which showed filled joint spaces after primary treatment. Methods: We retrospectively reviewed 19 cases of developmental dysplasia of the hip: (1) who showed a widened joint space on radiographs after primary treatment; and (2) whose magnetic resonance imaging showed that the widened joint space was accompanied by acetabular cartilage hypertrophy and/or was filled with fibrous tissues. All patients were over 1 year old at the time of primary reduction (reduction was closed in 4 patients, open in 6, and open with pelvic osteotomy in 9). Thirteen patients received at least 1 secondary treatment. Final results were classified using a modified Severin classification. Results: Final outcomes were satisfactory in 10 (52.6%) and unsatisfactory in 9 (47.4%). The widened joint spaces gradually filled with bone, resulting in a shallow acetabulum in the patients with unsatisfactory results. Of 9 patients who underwent combined pelvic osteotomy at the time of primary reduction, results were satisfactory in 6 (66.7%), whereas all patients who had only closed or open primary reduction had unsatisfactory results. Conclusions: Combined pelvic osteotomy at the time of primary reduction is advisable in hips with widened joint spaces. However, hips with filled joint spaces after primary treatment often have unsatisfactory results even after additional pelvic and/or femoral osteotomy. Level of Evidence: Level IV—prognostic study.