For a study in single-level disc herniation, a retrospective analysis was performed on data from 251 patients who were enrolled in 2 randomized, double-blinded clinical trials comparing the clinical outcomes of anterior cervical discectomy and arthroplasty (ACDA) to anterior cervical discectomy and fusion (ACDF) and anterior cervical discectomy (ACD). Researchers aimed to see if the ACDA method, compared to ACDF or ACD without instrumentation, provided better clinical results 2 years after surgery in the complete group of patients or a subgroup of patients. The cervical disc prosthesis was developed to improve clinical outcomes following ACD. At baseline, 1 year, and 2 years after surgery, the Neck Disability Index (NDI), as well as subscales of the 36-item short-form health survey (SF-36) and the McGill pain score, were collected. Complications and reoperations were also assessed. Age, disc height, BMI, smoking, and sex were used to perform preliminary subgroup analysis. The NDI dropped to around 50% of the baseline value in all treatment arms, with marginal mean NDI changes ranging from 0.4 to 1.1 on a 100-point NDI scale, with confidence intervals never exceeding the 20-point minimal clinically meaningful difference (MCID). The results of secondary outcome parameters were similar. After 2 years, preliminary subgroup analysis revealed no clinically significant differences in NDI between therapies. When data from two Randomised Controlled Trials are combined, it may be determined that there is no clinical benefit for ACDA 2 years following surgery compared to ACDF or ACD. Preliminary subgroup analysis revealed that treatment groups’ outcomes were similar, and no subgroup could be identified that benefited more from ACD, ACDF, or
