Preclinical evaluation of a mini-arthroplasty implant based on polyetheretherketone and Ti6AI4V for treatment of a focal osteochondral defect in the femoral head of the hip.

A mini or partial arthroplasty may offer the advantages of reduced pain, shorter hospital stay, and increased range of motion, which are beneficial for the treatment of large-sized focal osteochondral defects. We aimed to evaluate the in vivo histologic response and function of our nonresorbable, composite structure implant, developed using polyetheretherketone (PEEK) and Ti6AI4V alloy, as a treatment for full-thickness osteochondral defects in the femoral head of the hip using a goat model. The gross and imaging appearance and histologic results were compared to those of a similar size cobalt-chromium-molybdenum (CoCrMo) alloy implant placed in a defect in the femoral head and evaluated up to 12 weeks. The X radiographs showed that there was no evidence of loosening of the implants for both the PEEK-Ti6AI4V and CoCrMo groups. Magnetic resonance imaging results showed no inflammatory signal findings in both PEEK-Ti6AI4V and CoCrMo implants. Macroscopically and histologically, there was lesser cartilage degeneration in the PEEK-Ti6AI4V implant than in the CoCrMo implant. The modified macroscopic articular evaluation score was lower in the PEEK-Ti6AI4V group than in the CoCrMo group (p < 0.05), and the histological score of the periprosthetic and acetabular cartilage was lower in the PEEK-Ti6AI4V group than in the CoCrMo group (P < 0.05). The micro-computed tomography results showed that the uncemented PEEK-Ti6AI4V implant has better osseointegration and higher bone-implant contact than the cemented CoCrMo implant. The peri-implant bone mass was higher in the PEEK-Ti6AI4V implant(p < 0.05). Meanwhile, the optical profile analytical results showed that the surface roughness of the cartilage in the acetabulum was higher in the CoCrMo group. In conclusion, the mini-arthroplasty implant based on PEEK-Ti6AI4V was superior to an identical CoCrMo alloy implant as a treatment for local osteochondral defect in the femoral head, owing to its in vivo cartilage protection and better osseointegration.

Measurement of proximal femoral morphology and analysis of 500 cases in Hunan Province / 中南大学学报(医学版)

Objective:To evaluate the effect of age and gender on the femoral morphology to guide prosthesis selection in operation and design. Methods:A total of 500 females and males were collected from the departments of orthopedics and medical radiology, Second Xiangya Hospital, Central South University. Informed consent was obtained from all subjects. All patients underwent anteroposterior position scan of the left or right hip joint using Philips Digital Diagnost DR system. The shooting range included the hip joint and at least 2/3 of the proximal femur. The images were measured with Onis 2.3 software. We measured 13 parametersfromthepatients,includingtheexternalparamtersofthefemur,radius-lengthparameters of femoral medullary cavity, and morphological parameters of the femoral medullary cavity. Results:Compared with Westeners, the offset was smaller, while the neck shaft angle was signiifcantly larger in Chinese population (P0.05). The main differences between 31 and 70 years old were the diameter of femoral head, the offset of isthmus, the medullary cavity diameter and extracortical width at isthmus level and the medullary cavity diameter at the level of the lesser trochanter (P<0.05). The modullary transverse diameter at 20 mm below the lesser trochanter and isthmus and extracortical width of isthmus in the male and female group was positively correlated with age (P<0.01), while the parameters of the proximal femoral canal morphology in the female group were negatively correlated with age. The female canal parameters had a stronger correlation. Conclusion:Chinese proximal femoral parameters are signiifcantly different from Westerners. When people, especially females, get older, the medullary cavity diameter of the isthmus and proximal femur becomes wider and the morphology of the femur becomes straight. The difference in the femoral morphology between the male and female decline with the age. There is almost no difference for the over 70 years old. For the 31-70 years old, The male femoral cavity diameter is larger and the position of isthmus is lower than in the females.