Cemented cruciate-retaining total knee arthroplasty in osteoarthritis: a comparison of pegged and stemmed tibial designs.

We compared the clinical, functional, and radiographic outcomes between pegged (37 knees in 37 patients) and stemmed (33 knees in 31 patients) tibial designs in patients undergoing primary cemented total knee arthroplasty (TKA) for osteoarthritis (OA). Outcomes were evaluated using the knee society score (KSS-Clinical and Function scores) and knee injury and osteoarthritis outcome score (KOOS-pain, symptoms, stiffness, and function scores) at 6, 12, and 24 months postoperatively. Pre- and postoperative radiographs were evaluated for alignment and tibial coverage. All the outcome scores showed statistically significant improvement compared with the respective preoperative ones in both the groups at all points in time (p ≤ 0.039). None of the outcome scores were significantly different between the two groups at any point in time (p ≥ 0.06). Postoperative knee range of motion was also similar between the two groups at all points in time (p ≥ 0.641). Mean percentage tibial coverage was significantly greater in the pegged group as compared with the stemmed one (95.5% vs. 93.4%, p = 0.036). Incidence of complications (p = 0.617) and rates of revision (p = 1.000) were similar between the two groups. In conclusion, comparison of clinical and functional outcomes between the pegged and the stemmed tibial designs in TKA for primary OA did not reveal any significant difference at 2 years.

Administration of PTH and ibandronate increases ovariectomized rat compact bone viscoelasticity.

In this study, the bone mineral density (BMD), geometry, macroscopic viscoelastic properties and mechanical strength in five different groups of Sprague-Dawley rats (sham operated, ovariectomized with vehicle, parathyroid hormone and/or ibandronate administration) were examined by peripheral quantitative computed tomography (pQCT), dynamic mechanical analysis (DMA) and three-point bending test. At the end of the study, storage modulus (E'), loss tangent (tanδ), ultimate force (Fu) and stiffness (S) had greatly decreased in vehicle-treated ovariectomized group as compared to sham group (p<0.05). The concurrent administration of parathyroid hormone and ibandronate group exhibited the largest cortical area (Ct.Ar) and thickness (Ct.Th), E', tanδ (0.3Hz) and subsequently highest Fu as compared to the mono-therapy groups (p<0.05). However, significant changes were not observed in the BMD values of different groups (p>0.05). The relationships between these potential predictors of bone strength (E', tanδ, BMD and Ct.Ar) and bone mechanical strength parameters (Fu, S and ultimate stress σu) were also examined. Interestingly, during normal daily activity frequency range (0.9-6Hz), tanδ and Fu were positively correlated. Taken together, these data suggest that DMA can serve as an effective tool to assess bone strength which would be ignored under the normal clinical screenings due to an unchanged BMD. DMA can therefore be used as a better tool to assess the osteoporotic drug efficacy.

Bicompartmental versus total knee arthroplasty for medio-patellofemoral osteoarthritis: a comparison of early clinical and functional outcomes.

Severe medio-patellofemoral osteoarthritis (MPFOA) is often managed with a total knee arthroplasty (TKA). Bicompartmental knee arthroplasty (BKA), as compared with TKA can offer a bone and ligament preserving solution for MPFOA. We aimed to compare the early clinical and functional outcomes of modular BKA (n = 16) with TKA (n = 20) in MPFOA. Knee Society Score (KSS-clinical and function scores) and Knee injury & Osteoarthritis Outcome Score (KOOS-pain, symptoms, stiffness, and function scores) were recorded at 6, 12 and 24 months postoperatively and compared between the two groups. Pre- and postoperative radiographs were evaluated for alignment and radiolucencies. We found that none of the outcome scores were significantly different (p ≥ 0.137) between the two groups at any point in time. Postoperative knee range of motion (ROM) was significantly greater in the BKA group at all points in time (p ≤ 0.007). None of the patients in either group were revised or pending revision at the end of 24 months. To conclude, modular BKA resulted in better knee ROM but similar clinical and functional scores than TKA in MPFOA at short term. Modular BKA is a viable option for MPFOA but may not necessarily result in significant superior functional outcomes than with TKA.

Positive alterations of viscoelastic and geometric properties in ovariectomized rat femurs with concurrent administration of ibandronate and PTH.

Besides bone mineral density (BMD), structural and nano-level viscoelastic properties of bone are also crucial determinants of bone strength. However, treatment induced viscosity changes in osteoporotic bone have seldom been characterized. In this study, the effects of anabolic, antiresorptive and concurrent treatments on ovariectomized rat bones were thoroughly analyzed using multiple bone strength parameters. A total of 52 female Sprague-Dawley rats of 3 months age were divided into 5 groups and subjected to sham (SHM group) or ovariectomy surgery (OVX, PTH, IBN and COM groups). Weekly low-dose parathyroid hormone (PTH) and/or ibandronate or its vehicle was administered subcutaneously to the respective groups starting from 4th week post-surgery. Four rats per group were euthanized every 4 weeks and their femurs were harvested. The BMD, micro-architectural parameters, cortical bone geometry and viscoelastic parameters were measured at the distal femoral metaphysis. Our results showed that PTH, ibandronate or its concurrent treatment can effectively reverse ovariectomy induced deteriorations in both trabecular and cortical bone. Different drugs had selective effects especially in preserving geometric and viscoelastic properties of the bone. The concurrent administration of PTH and ibandronate was shown to offer an added advantage in preserving mean BMD and had a positive effect on cortical bone geometry, resulting from an increased periosteal formation and a decreased endocortical resorption. Viscosity (η) was prominently restored in combined treatment group. It is in accordance with an observed denser alignment of collagen fibers and hydroxyapatite crystal matrix with fewer pores, which may play an important role in hindering fracture propagation.

Ibandronate does not reduce the anabolic effects of PTH in ovariectomized rat tibiae: a microarchitectural and mechanical study.

Osteoporosis remains a challenging problem. Understanding the regulation on osteoclast and osteoblast by drugs has been of great interest. Both anabolic and anti-resorptive drugs yield positive results in the treatment of osteoporosis. However, whether the concurrent administration of parathyroid hormone (1-34) and ibandronate may offer an advantage over monotherapy is still unknown. This study, therefore, attempts to compare the efficacy of two therapeutical approaches and to investigate the beneficial effects in concurrent therapy in a rat model using three-point bending, pQCT and µCT analysis. A total of 60 female Sprague-Dawley rats of age 10 to 12 weeks were divided into 5 groups (SHAM, OVX+VEH, OVX+PTH, OVX+IBAN, OVX+PTH+IBAN) and subjected to ovariectomy or sham surgery accordingly. Low-dose parathyroid hormone (PTH) and/or ibandronate or its vehicle were administered subcutaneously to the respective groups starting from 4th week post-surgery at weekly intervals. Three rats from each group were euthanized every 2 weeks and their tibiae were harvested. The tibiae were subjected to metaphyseal three-point bending, pQCT and µCT analysis. Serum biomarkers for both bone formation (P1NP) and resorption (CTX) were studied. A total of 11 indices showed a significant difference between SHAM and OVX+VEH groups, suggesting the successful establishment of osteoporosis in the rat model. Compared to the previous studies which showed impedance from bisphosphonates in combination therapy with PTH, our study revealed that ibandronate does not block the anabolic effects of PTH in ovariectomized rat tibiae. Maximum load, strength-strain indices and serum bone formation markers of OVX+PTH+IBAN group are significantly higher than both monotherapy groups. With the proper ratio of anabolic and anti-resorptive drugs, the effect could be more pronounced.

Bone mineral density and hip axis length in Singapore's multiracial population.

Ethnic differences in bone density and hip geometry are known to exist, even within the same population. A recent study in Singapore showed that there were significant racial differences in hip fracture rates, with Chinese having the highest incidence of hip fractures. The aim of this study was to compare the bone mineral density (BMD) and hip axis length in Chinese, Malay, and Indian women. A total of 1575 women aged 20-59 yr were recruited, of which 77.6% (1222) were Chinese, 7.7% (122) Malays, and 14.7% (231) Indians. There was no significant difference in peak BMD of both lumbar spine and femoral neck among the three ethnic groups. However, in the older age group (50-59 yr), both Chinese and Malay women had significantly lower femoral neck BMD compared to Indian women. There was no significant loss in BMD of the lumbar spine between the second and fifth decades in all the three races. Between the second and fifth decade, Chinese and Malay women had significant bone loss in the femoral neck of 6.6% and 8.2%, respectively, whereas Indian women did not show any significant bone loss. Chinese women had significantly longer hip axis length compared to either Malay or Indian women (9.87 +/- 0.52 cm vs 9.67 +/- 0.49 cm; p < 0.005; and 9.69 +/- 0.55 cm, p < 0.05, respectively). The initial findings suggest racial differences in bone density and hip geometry exist in the local community. Future research should include prospective, longitudinal studies to determine the age-related bone loss in these three racial groups. It is also important to investigate the differences of spine and hip fracture rates and their relationship with bone density and hip axis length.