2020 IPPS final rule updates MS-DRG assignments for musculoskeletal diseases

The 2020 IPPS final rule introduced several MS-DRG changes within Major Diagnostic Category (MDC) 8, effective October 1, which could affect reimbursement for certain orthopedic infections, neuromuscular scoliosis, secondary scoliosis and kyphosis.

The following ICD-10-CM codes were added to the list of principal diagnosis codes for MS-DRGs 485, 486, and 487 (Knee procedure with principal diagnosis of infection with MCC, with CC, and without CC/MCC, respectively):

• A18.02, tuberculous arthritis of other joints
• M01.X6-, direct infection of knee in infectious and parasitic diseases classified elsewhere
• M71.06-, abscess of bursa, knee  
• M71.16-, other infective bursitis, knee

The following ICD-10-CM codes were removed from the list of principal diagnoses for MS-DRGs 485, 486, and 487, as they do not describe an infection of the knee:

• M86.9, osteomyelitis, unspecified
• T84.50XA, infection and inflammatory reaction due to unspecified internal joint prosthesis, initial encounter
• T84.51XA, infection and inflammatory reaction due to internal right hip prosthesis, initial encounter
• T84.52XA, infection and inflammatory reaction due to internal left hip prosthesis, initial encounter
• T84.59XA, infection and inflammatory reaction due to other internal joint prosthesis, initial encounter
• T84.60XA, infection and inflammatory reaction due to internal fixation device of unspecified site, initial encounter
• T84.63XA, infection and inflammatory reaction due to internal fixation device of spine, initial encounter
• T84.69XA, infection and inflammatory reaction due to internal fixation device of other site, initial encounter

ICD-10-CM codes describing neuromuscular scoliosis (M41.40, M41.44, M41.45, M41.46, and M41.47) were added to the list of principal diagnoses for MS-DRGs 456, 457, and 458 (Spinal fusion, except cervical, with curvature/malignancy/infection).

The ICD-10-CM codes describing secondary scoliosis and secondary kyphosis (M40.10, M40.14, M40.15, M41.50, M41.54, M41.55, M41.56, and M41.57) were added to the list of principal diagnosis codes in MS-DRGs 456, 457, and 458.

Diagnosis codes describing conditions involving the cervical region were removed from MS-DRGs 456, 457, and 458.

For additional information on these changes, see p. 150-178 of the final rule.