Longer treatment period in distraction osteogenesis (DO) of the lower extremity leads to more frequent complications. We have developed a new technique of transplantation of culture-expanded bone marrow cells (BMCs) and platelet-rich plasma (PRP) during DO to accelerate new bone formation. To assess the efficacy of this cell therapy, retrospective comparative study was conducted between the bones treated with BMC and PRP and the bones treated without BMC and PRP during DO in patients with achondroplasia (ACH) and hypochondroplasia (HCH). Fifty-six bones in 20 patients (ACH, 16; HCH, 4) that were lengthened in our hospital were divided into 2 groups. Twenty-four bones (femora, 12; tibiae, 12) in 11 patients (boys, 7; girls, 4) were treated with BMC and PRP transplantation (BMC-PRP group), whereas 32 bones (femora, 14; tibiae, 18) in 9 patients (boys, 3; girls, 6) did not undergo additional cell therapy (control group). The parameters, including the age at operation, the increase in length, and the healing index, were compared between the 2 groups. The clinical outcome was also compared between the femoral and tibial lengthenings. Bone marrow cells (average number, ± SD, 3.2 ± 1.37 × 107 cells) and PRP (average platelet concentration ± SD, 2.36 ± 0.57 × 106 cells/μL) were transplanted. Although there were no significant differences in the age at operation and the length gained between the 2 groups, the average healing index of the BMC-PRP group (27.1 ± 6.89 d/cm) was significantly lower than that of the control group (36.2 ± 10.4 d/cm) (P = 0.0005). The femoral lengthening showed significantly faster healing than did the tibial lengthening in the BMC-PRP group (P = 0.0092). Transplantation of BMC and PRP shortened the treatment period by accelerating new bone regeneration during DO of the lower extremity in patients with ACH and HCH, especially in the femoral lengthening. Therapeutic studies, level III (retrospective comparative study).

The Pavlik harness is a widely used and effective means of initial treatment of developmental dysplasia of the hip (DDH), but some hips fail to stabilize with the use of harness and avascular necrosis (AVN) of the femoral head can occur. Predictive factors for unsuccessful Pavlik harness treatment should be determined for appropriate indication of the treatment and prevention of AVN. The outcome of Pavlik harness treatment for DDH was retrospectively examined in 221 hips of 210 patients who were treated initially at our institution and followed up for at least 1 year after the application of the harness. Univariate analysis was performed to determine predictors for failure of reduction and for the incidence of AVN by using the Mann-Whitney U test for continuous variables and the Fisher exact test or the Pearson test for categorical variables. Next, independent multivariate predictors for the failure of reduction and the incidence of AVN were identified using logistic regression analysis. One hundred and eighty-one hips were reduced and the overall rate of reduction was 81.9%. AVN that was diagnosed according to the criteria of Salter et al was identified in 16 of the 181 reduced hips and the rate of incidence of AVN was 8.8%. Bilaterality and decreased distance “a,” as defined by Yamamuro and Chene, were statistically significant univariate and multivariate risk factors for the failure of reduction. Between them, distance a was the most powerful predictor. Adduction contracture of the hip (abduction with the hips flexed to 90 degrees <60 degrees) was the only significant univariate and multivariate predictor for the incidence of AVN. Distance a and adduction contracture of the hip were important predictors for the outcome of Pavlik harness treatment. We concluded that the Pavlik harness is a very safe and effective means of DDH treatment for the hips with abduction ≥60 degrees and distance a ≥6 mm. Therapeutic studies, level III (retrospective study).

Background Transplantation of culture-expanded bone marrow cells (BMC) and platelet-rich plasma (PRP) during limb lengthening shorten the treatment period by accelerating callus formation, but the direct effects of BMC and PRP on the regeneration of the bone have not been determined. Methods Fifty-one bones (23 femora, 28 tibiae) in 28 patients (17 males, 11 females), with an average age of 15.0±3.21 years, were lengthened by treatment with BMC and PRP. Clinical outcome was compared between the 51 bones with BMC and PRP treatment and the 60 bones without cell therapy. The parameters including age at surgery, length gained, healing index (HI), number of BMC, bone-specific alkaline phosphatase (BAP) activity of BMC, and PRP concentration, were compared between the femur and the tibia treated with BMC and PRP. Linear regression analysis was then performed to correlate the HI and other variables. Results The HI of the BMC and PRP groups was significantly lower than that of the control group. Average HI, amount of lengthening, number of BMC, BAP activity, and PRP concentration were 30.0±6.72 days/cm, 8.10±2.90 cm, 1.35±0.56×10⁷, 9.02±3.98 U/L, and 2.4±0.7×10⁶ /UL, respectively. There were no significant differences in the length gained, the number and BAP activity of BMC, and the PRP concentration between the femur and the tibia. Femoral lengthening showed significantly faster healing than tibial lengthening, although the age at surgery was significantly older in femoral lengthening. A negative relationship between the HI and the length gained was observed in the tibia. In the femur, there was a negative linear relationship between the HI and the number and BAP activity of BMC, whereas no significant correlations were detected in the tibia. Conclusions In femoral lengthening, decrease in the HI was remarkable by BMC and PRP transplantation, and there was a progressive increase in bone healing as the number and the osteoblastic differentiation of transplanted BMC increased. Our results suggested that regionally varying bone-forming processes by cell transplantation might be related to local blood supply and soft tissue covering. Level of Evidence Therapeutic retrospective study, level III.

Background: In children over 6 months of age with developmental dysplasia of the hip (DDH), achieving a concentrically reduced hip while avoiding avascular necrosis (AVN) is challenging. The utility of gradual reduction (GR) using traction has insufficient evidence. We therefore report the long-term outcome of GR using overhead traction (OHT). Methods: We retrospectively reviewed 67 patients with DDH (75 hips) treated with GR using OHT over 6 months of age. The age at reduction ranged from 7 months to 4 years. All patients were followed up until skeletal maturity with a mean duration of 15.6 years. Pelvic radiographs were used to assess AVN, acetabular development, and the Severin classification. We determined the factors affecting the outcome at skeletal maturity. Results: Seventy-two hips (96%) were successfully reduced, 2 required subsequent closed reduction and 1 underwent open reduction. AVN occurred in 2 hips (2.7%). Among 48 hips (64%) with residual acetabular dysplasia, 31 were treated with Salter innominate osteotomy (SIO) between 5 and 6 years of age. Finally, 62 hips (82.7%) showed satisfactory outcome (56 in Severin class I and 6 in class II), whereas 13 showed unsatisfactory outcome (class III). Although we found no significant factors affecting the outcome, most of the hips treated with SIO were included in the satisfactory group. Conclusions: GR using OHT could effectively minimize the risk of developing AVN in patients with DDH over 6 months of age at presentation. SIO at preschool age may play a beneficial role in the long-term outcome of GR using OHT. Level of Evidence: Level IV—therapeutic studies (case series).