Comparison of compression, tensile strength, and surface roughness between local SS316L and standard implants in total hip arthroplasty: An in vitro study

Biomechanical strength (e.g., compressive/tensile resistance) and surface roughness (e.g., Ra <0.5 µm) are critical determinants of hip implant stability. SS316L implants exhibit these properties, making them suitable for arthroplasty. However, Indonesia relies on costly imported SS316L implants, necessitating local production via hot forging. This study compares the biomechanical performance of locally forged SS316L, imported SS316L, and standard cobalt-chrome (CoCr) implants. An in vitro experimental study tested the three implant groups per ISO 7206-10, evaluating compressive strength, tensile strength, and surface roughness (via universal tester and profilometer). Data were analyzed using ANOVA with post-hoc Tukey tests, reporting p-values and effect sizes (η²). Compression tests revealed no significant differences (mean ± SD: local SS316L = 47.62 ± 6.04 N; imported SS316L = 53.84 ± 8.54 N; CoCr = 61.53 ± 25.33 N; *p* = 0.588, η² = 0.08). Tensile strength of local SS316L (1,154.33 ± 205.91 N) matched CoCr (1,011.66 ± 200.93 N; *p* > 0.05), while imported SS316L underperformed (137.66 ± 69.78 N; *p* = 0.001, η² = 0.91). Surface roughness of local SS316L (0.31 ± 0.12 µm) and CoCr (0.41 ± 0.12 µm) met optimal thresholds (Ra <0.5 µm), unlike imported SS316L (0.99 ± 0.18 µm; *p* = 0.002, η² = 0.85). Locally manufactured SS316L implants demonstrate comparable biomechanical performance to CoCr and superior surface quality versus imported SS316L. The poor tensile strength and high roughness of imported SS316L suggest taper angle mismatches (6° vs. optimal 5.76°) and suboptimal finishing. These findings support domestic production of cost-effective, high-quality implants.