In our previous work [Biomaterials, 2014; 35, 6687], melt processing of ultrahigh molecular weight polyethylene (UHMWPE) for knee implants was realized by a modified injection molding technology, where the mechanical performance of UHMWPE parts was greatly enhanced. To advance the wear resistance, UHMPWE was cross-linked and then melt processed in this study. The results shows that the wear rates decreased substantially from 12.1 ± 1.1 mg/MC for compression molded UHMWPE (CM-UHMWPE) to 1.5 ± 0.7 mg/MC for melt injection molded xUHMWPE (MP-xUHMWPE). Owing to introducing a controllable shear flow, large amounts of self-reinforced oriented lamellae with a unique interlocked architecture were formed. The mechanical properties were thus remarkably enhanced, which compensated for the loss caused by cross-linking. Especially, the yield strength and ultimate tensile strength increased significantly by 98.3% and 51.0%, from 23.5 ± 1.1 and 41.6 ± 1.4 MPa for CM-UHMWPE up to 46.6 ± 0.7 and 62.8 ± 1.3 MPa for MP-xUHMWPE, respectively. Very interestingly, melt processing recombined the residual free radicals in MP-xUHMWPE induced by radiation cross-linking effectively, improving the oxidation stability. Our work provides a promising strategy for high-performance UHMWPE bearings, enabling its use under high stress applications, particularly for younger and more active patients.