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Introduction: Human pluripotent stem cells have the potential to differentiate into different cell lineages of the human body, including dopaminergic (DA) neurons. Previous studies have shown that stem-cell--derived DA neurons can improve the motor deficits of Parkinson's disease (PD) animal models. That is why current research interests focus on the development of stem-cell--derived neural cells for transplantation therapies for PD patients., Areas Covered: This review article emphasizes the safety and efficacy requirements of human pluripotent stem-cell--derived neural cells and usage of reliable preclinical animal models prior to clinical trials. The current advances and hurdles related to cell production, differentiation and transplantation are also summarized., Expert Opinion: Before entering the clinic, transplantable cell populations must be differentiated and characterized according to good manufacturing practice (GMP) regulations both in vitro and in vivo. Taking into account the rapid development of the stem-cell field and technological improvements in cell preparations and GMP facilities, we think that pluripotent stem-cell--derived DA neurons will offer a relevant cell therapy option for treatment of PD in the near future.

Background: There have been few studies evaluating patient-reported quality of life outcomes after hip revision with impaction bone grafting., Patients and Methods: The inclusion criteria were aseptic loosening after primary arthroplasty performed for osteoarthrosis, and first-time revision with impacted morselized allograft bone and cemented Exeter stem. During a 4-year period, 35 patients were eligible and all were included. The Nottingham Health Profile (NHP) was completed by the patients and the Charnley hip scores recorded by the examining surgeon preoperatively, after 6 months and yearly up to 4 years (28 patients) postoperatively. For comparison, 35 osteoarthrotic patients completed the NHP 4 years after cemented Exeter primary arthroplasty., Results: At 4 years, the NHP scores for the revision patients did not differ significantly from those recorded in the primary arthroplasty group. Among the revision patients, mixed model analysis showed improvement in NHP pain (p < 0.001) and physical mobility scores (p = 0.002). The effect size at 4 years was large for pain (1.2) and moderate for physical mobility (0.6). The major improvement was recorded at 6 months, with no further substantial change observed. The correlations between the NHP and Charnley scores were weak or moderate (r, -0.15 to -0.67)., Interpretation: Hip revision with impaction bone grafting leads to substantially improved quality of life, similar to that 4 years after primary arthroplasty.

Background: Impaction grafting in hip revision surgery is widely used but studies with mid- and long-term follow-up are scarce., Patients, Methods and Results: A 5-year radiostereometric (RSA) follow-up of 15 hip revisions with the Exeter stem, morselized impacted allograft bone and cement revealed that 3 stems had not migrated between 2 and 5 years after revision, 11 stems had migrated to a minor degree in at least 1 direction, and 1 stem was loose according to RSA but without any radiographic signs of loosening or pain. The pain score was comparable to primary arthroplasties., Interpretation: From a 5-year perspective, first-time hip revisions for aseptic loosening with impacted morselized allograft bone and cement appear to yield good clinical results, although stem migration continues to a minor degree 2 years after revision.

Background: The design of the Exeter stem may facilitate distal migration, but radiostereometric analysis (RSA) studies have been limited to 2 years of follow-up., Patients and Methods: We followed migration of the Exeter femoral stems in 22 primary hip arthroplasties for 5 years with RSA., Results: All stems migrated distally and the median migration at 2 years was 1.34 mm, while at 5 years it was 1.77 mm. 7 stems migrated above accuracy between 3 and 5 years. (RSA) evaluation of the cement mantle could be performed in 14 cases, and in 5 slight migration was found. Most of the stems rotated towards retroversion and the median rotation at 2 years was 1.2 degrees, while at 5 years it was 1.6 degrees. We found 1 patient with impending clinical failure but no deviation in the RSA migration pattern, and 1 patient with unstable migration pattern but no clinical symptoms., Interpretation: We found a greater distal migration of the Exeter stem for longer periods of time than seen with other types of cemented implants., (Copyright 2004 Taylor & Francis)

We revised the hip (6 stems and 5 sockets) with impacted morselized allografts and cement in 6 patients. We followed prosthetic migration by roentgen radiostereometric analysis (RSA) every 7th day for 6 weeks after the first (index) examination performed on the first postoperative day before mobilization. Most of the migration occurred during the first 2 weeks. In most cases more than half of the distal stem migration was seen between the 1st and 14th days. In all cases, the stem and socket migrations slowed down gradually and several prosthetic components had become stable after 5 weeks. We conclude that it is essential to perform the index RSA examination on the 1st or 2nd day after surgery and to state when and how weight bearing should be permitted. Otherwise it will be difficult to compare prosthetic migration in various studies and define normative values for migration predicting survival.

In a consecutive series of hip revisions due to mechanical loosening, using impacted morselized allografts and cement, we followed 21 acetabular components by radiostereometric analysis (RSA) during 2 years. All but 1 acetabular component migrated in the proximal direction (median 2.1 (0.5-6.4) mm). 6 components migrated in the medial direction (median 0.8 (0.4-1.2) mm) and 6 in the lateral (median 0.8 (0.4-2.0) mm). 14 components migrated in the posterior direction (median 0.8 (0.3-2.3) mm) and 1 in the anterior 0.6 mm. The migration rate gradually decreased in all directions, but 7 acetabular components still migrated in at least 1 direction (median 0.3-0.6 mm) between 1.5 and 2 years postoperatively.

We followed 23 patients from the primary total hip arthroplasty to revision for a bacteriologically proven deep infection with a low virulent organism. The median time to revision was 14 (4-65) months. During this period, the maximum ESR value was median 50 (22-110) mm and the maximum CRP value was 35 (9-95) mg/L. 25 of the 98 CRP values recorded were normal (< 9 mg/L) and 22/89 ESR values were below 30 mm/h. In 6 patients, all CRP values were below 20 mg/L, but 5 of these patients had an ESR > 30 mm. Before the revision, normal values for both tests were found in only 1 patient. Both normal values and slight-to-moderate increases in ESR and/or CRP are consistent with a low-grade periprosthetic hip infection. We recommend that ESR should be determined preoperatively in all patients scheduled for total hip replacement to establish a baseline.

We performed, in a cross-sectional study, dual energy X-ray absorptiometry (DXA) among 15-16-year-old boys (n 58) and girls (n 44) living in an urban area and among boys (n 82) and girls (n 66) of the same age from a rural area. We measured bone mineral density (BMD) of the total body, the lumbar spine and the hip. In the rural population, we found significantly higher BMD levels in the lumbar spine (14% for the boys and 12% for the girls) and the total body (6.9% for the boys and 3.4% for the girls). We detected no significant differences in the hip BMD. Adolescents in rural areas seem to develop a higher peak bone mass and thereby presumably have a lower risk of developing fragility fractures.