Table 2.
Definitions and stratification of THA complications*
| Number | Complication | Definition | Stratification |
|---|---|---|---|
| 1 | Bleeding | Postoperative bleeding requiring surgical treatment (ICD-9 998.11) | • Grades 1 and 2 are not applicable • Grade 3, 4, or 5 depending on severity |
| 2 | Wound complication | Failure of wound healing requiring reoperation or a change in THA protocol (ICD-9 998.32) | • Grade 1 is not applicable • Grade 2 or 3 depending on severity • Grade 4 or 5 if complications arise from treatment |
| 3 | Thromboembolic disease | Symptomatic thromboembolic event requiring more intensive, nonprophylactic anticoagulant or antithrombotic treatment during the first 3 months after index THA (ICD-9 453.40) | • Grade 1 is not applicable • Grade 2, 3, 4, or 5 depending on severity |
| 4 | Neural deficit | Postoperative neural deficit (sensory or motor) related to the index THA (ICD-9 997.09) | • Grade 1–3 if complete recovery • Grade 4 if permanent disability • Grade 5 if complications arise from treatment |
| 5 | Vascular injury | Intraoperative vascular injury requiring surgical repair, bypass grafting, or stenting (compartment syndrome or amputation should be reported) (ICD-9 997.20) | • Grade 1 is not applicable • Grade 3, 4, or 5 depending on severity |
| 6 | Dislocation/instability | Dislocation of the femoral head out of the acetabulum or recurrent symptomatic subluxation of the hip (direction of instability and type of treatment should be recorded) (ICD-9 996.42) | • Grade 1, 2, or 3 depending on severity • Grade 4 or 5 if complications arise from treatment |
| 7 | Periprosthetic facture | Periprosthetic fracture of the proximal femur or the acetabulum (intraoperative fracture or postoperative fracture should be recorded) (operative of nonoperative treatment should be recorded) (ICD-9 996.44) | • Grade 1 not applicable • Grade 2 for nonoperative treatment • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 8 | Abductor muscle disruption | Symptomatic abductor dysfunction, which was not present before the operation, associated with positive Trendelenburg sign and use of an ambulatory assist (cane, crutch, walker) for treatment of limp or weakness (nonoperative treatment should be recorded) (ICD-9 727.69) | • Grade 1 is not applicable • Grade 2 for nonoperative treatment • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 9 | Deep periprosthetic joint infection | A deep periprosthetic joint infection can be diagnosed when there is a sinus tract communicating with the prosthesis; or a pathogen is isolated by culture from at least two separate tissue or fluid samples obtained from the affected prosthetic joint; or 4 of the following 6 criteria exist: elevated ESR and serum CRP concentration, elevated synovial WBC count; elevated synovial PMN; presence of purulence in the affected joint; isolation of a microorganism in one culture of periprosthetic tissue or fluid; or > 5 neutrophils/high-power field in 5 high-power fields observed from histologic analysis of periprosthetic tissue at x 400 magnification (reference) (ICD-9 996.66) | • Grades 1 and 2 are not applicable • Grade 3 if treated successfully • Grade 4 if resection arthroplasty or permanent disability occurs • Grade 5 if more complications arise from treatment |
| 10 | Heterotopic ossification | Symptomatic heterotopic ossification at 1 year after operation associated with stiffness, reduced ROM, and radiographic grade of Brooker III or IV (ICD-9 728.13) | • Grades 1 and 2 not applicable • Grade 3 for operative treatment • Grade 4 for permanent disability • Grade 5 if more complications arise from treatment |
| 11 | Bearing surface wear | Wear of the bearing surface that is symptomatic or requires operation (ICD-9 996.46) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grades 4 or 5 if more complications arise from treatment |
| 12 | Osteolysis | Expansile lytic lesion adjacent to one of the implants that is greater than or equal to 1 cm in any one dimension or increasing in size on serial radiographs/CTs (ICD-9 996.45) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grades 4 or 5 if more complications arise from treatment |
| 13 | Implant loosening | Implant loosening confirmed intraoperatively or identified radiographically as a change in implant position or a progressive radiolucent line at the bone-cement or bone-implant interface (ICD-9 996.41) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 14 | Cup-liner dissociation | Dissociation of the cup liner from the acetabular shell (ICD-9 996.47) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 15 | Implant fracture | Implant fracture (specific implant should be recorded) (ICD-9 996.43) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 16 | Reoperation | Return to the operating room related to the index THA (reasons for reoperation should be recorded) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 17 | Revision | Removal or exchange of one or more of the THA implants (acetabular cup, acetabular liner, femoral head, femoral stem) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 18 | Readmission | Admission to the hospital for any reason during the first 90 days after THA (reasons for admission and relation to index THA should be recorded) | • Grades 1 and 2 are not applicable • Grade 3 for operative treatment • Grade 4 or 5 if more complications arise from treatment |
| 19 | Death | Death occurring for any reason during the first 90 days after THA (cause of death and relation to index THA should be recorded) | • Grades 1, 2, 3, and 4 are not applicable • Grade 5 |
* See Table 3 for grading scheme; ICD-9 = International Classification of Diseases, 9th Revision; ESR = erythrocyte sedimentation rate; CRP = C-reactive protein; WBC = white blood cell count; PMN = polymorphonuclear cells.