STATISTICAL ANALYSIS
Statistical analysis of this study was primarily descriptive to demonstrate the incidence for each code at each time interval. One-way analysis of variance, Chi-square analysis, and contingency tables were used to compare the incidence of each type of procedure throughout the various time intervals. A P-value of < 0.05 was considered statistically significant. Statistical analysis was performed using SPSS v.20 (International Business Machines).
RESULTS
A total of 47,207 cartilage procedures were performed from 2007 to 2011, including 43,576 MFX (92.3%) 640 ACI (1.4%), 386 open OATS (0.82%), 997 arthroscopic OATS (2.11%), 714 open OCA (1.51%), and 894 arthroscopic OCA (1.89%) procedures. A summary of the procedures performed, broken down by age and sex, is provided in Tables 1 and 2. A total of 25,149 male patients (53.3%) underwent surgical procedures compared to 22,058 female patients (46.7%). For each category of procedure (MFX, ACI, OATS, OCA), there was a significantly higher proportion of males than females undergoing surgery (P < .0001 for all). Surgical treatment with MFX was consistently the most frequently performed surgery across all age groups (92.31%), while cell-based therapy with ACI was the least frequently performed procedure across all age ranges (1.36%). Restorative OATS and OCA techniques were performed with the greatest frequency in the 15-year-old to 19-year-old age group, but were not utilized in patients over 64 years of age (Table 2).
Table 2. Breakdown of MFX, ACI, OATS, and OCA Procedures by Age | ||||
Age (y) | MFX | ACI | OATS | OCA |
10 to 14 | 572 | 22 | 74 | 47 |
15 to 19 | 1984 | 83 | 254 | 235 |
20 to 24 | 1468 | 54 | 140 | 144 |
25 to 29 | 1787 | 74 | 152 | 176 |
30 to 34 | 2824 | 114 | 152 | 204 |
35 to 39 | 4237 | 96 | 153 | 210 |
40 to 44 | 5441 | 103 | 166 | 217 |
45 to 49 | 7126 | 57 | 149 | 180 |
50 to 54 | 7004 | 25 | 83 | 140 |
55 to 59 | 6410 | 12 | 40 | 40 |
60 to 64 | 4409 | 0 | 20 | 15 |
65 to 69 | 269 | 0 | 0 | 0 |
70 to 74 | 45 | 0 | 0 | 0 |
Total | 43,576 | 640 | 1383 | 1608 |
Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation.
A summary of all reoperation data is provided in Tables 3 to 7 and Figures 1 and 2. The weighted average reoperation rates for all procedures were 5.87% at 90 days, 11.94% at 1 year, and 14.90% at 2 years following the index cartilage surgery. Patients who underwent MFX had reoperation rates of 6.05% at 90 days, 11.80% at 1 year, and 14.65% at 2 years. Patients who underwent ACI had reoperation rates of 4.53% at 90 days, 23.28% at 1 year, and 29.69% at 2 years. Patients who had open and arthroscopic OATS had reoperation rates of 3.122% and 5.12% at 90 days, 6.74% and 8.53% at 1 year, and 7.51% and 10.13% at 2 years, respectively. Patients who underwent open and arthroscopic OCA had reoperation rates of 2.52% and 3.91% at 90 days, 7.14% and 6.60% at 1 year, and 13.59% and 10.85% at 2 years (Table 3). There was a statistically significantly increased risk for reoperation following ACI within all intervals compared to all other surgical techniques (P < .0001); however, MFX had a greater risk factor (P < .0001) for conversion to arthroplasty at 6.70%. There was no significant difference between failure rates (revision OATS/OCA or conversion to arthroplasty) between the restorative treatment options, with 14 failures for OATS (9.52% of reoperations at 2 years) compared to 22 failures for OCA (12.7% of reoperations at 2 years, P = .358). Among the entire cohort of cartilage surgery patients, arthroscopic chondroplasty was the most frequent procedure performed at the time of reoperation at all time points assessed, notably accounting for 33.08% of reoperations 2 years following microfracture, 51.58% of reoperations at 2 years following ACI, 53.06% of reoperations at 2 years following OATS, and 54.07% of reoperations at 2 years following OCA (Figure 3, Tables 4–7).
Table 3. Comparison of Return to OR Following MFX, ACI, OCA, and OATS | |||||||
Procedure | Total No. of Cases in Study Period | No. of Reoperations at 90 Days | Return to OR Rate at 90 Days | No. of Reoperations at 1 Year | Return to OR Rate at 1 Year | No. of Reoperations at 2 Years | Return to OR Rate at 2 Years |
MFX | 43,576 | 2636 | 6.05% | 5142 | 11.80% | 6385 | 14.65% |
ACI | 640 | 29 | 4.53% | 149 | 23.28% | 190 | 29.69% |
Open OATS | 386 | 12 | 3.12% | 26 | 6.74% | 29 | 7.51% |
Arthroscopic OATS | 997 | 51 | 5.12% | 85 | 8.53% | 101 | 10.13% |
Open OCA | 714 | 18 | 2.52% | 51 | 7.14% | 97 | 13.59% |
Arthroscopic OCA | 894 | 161 | 3.91% | 59 | 6.60% | 97 | 10.85% |
Weighted average for all procedures | 5.87% | 11.94% | 14.90% |
Abbreviations: ACI, autologous chondrocyte implantation; MFX, microfracture; OCA, osteochondral allograft; OATS, osteochondral autograft transplantation; OR, operating room.
Table 4. Rate of Return to OR Following MFX (n = 43,574) | ||||
Procedure | CPT Code | 90 Days | 1 Year | 2 Years |
Knee arthroscopy | 29870 | 54 | 122 | 162 |
Knee arthroscopic drainage and lavage | 29871 | 84 | 102 | 104 |
Arthroscopic adhesions débridement | 29874 | 300 | 468 | 549 |
Arthroscopic synovectomy | 29875 | 324 | 528 | 611 |
Major arthroscopic synovectomy | 29876 | 557 | 926 | 1087 |
Knee arthroscopic chondroplasty | 29877 | 1063 | 1722 | 2112 |
Arthroscopic lysis of adhesions | 29884 | 61 | 129 | 171 |
Patellar arthroplasty | 27438 | 0 | 38 | 49 |
Medial or lateral knee arthroplasty | 27446 | 51 | 242 | 328 |
Medial and lateral knee arthroplasty | 27447 | 142 | 865 | 1212 |
Total | 2636 | 5142 | 6385 | |
Return to OR | 6.05% | 11.80% | 14.65% |
Abbreviations: CPT, Current Procedural Terminology; MFX, microfracture; OR, operating room.
Table 5. Rate of Return to OR Following ACI (n = 640) | ||||
Procedure | CPT Code | 90 Daysa | 1 Yeara | 2 Yearsa |
Revision ACI | 27412 | 29 | 33 | 35 |
Knee arthroscopy | 29870 | -1 | -1 | -1 |
Knee arthroscopic drainage and lavage | 29871 | -1 | -1 | -1 |
Arthroscopic adhesions débridement | 29874 | 0 | -1 | -1 |
Arthroscopic synovectomy | 29875 | -1 | -1 | -1 |
Major arthroscopic synovectomy | 29876 | -1 | 12 | 20 |
Knee arthroscopic chondroplasty | 29877 | -1 | 71 | 98 |
Arthroscopic lysis of adhesions | 29884 | -1 | 33 | 37 |
Patellar arthroplasty | 27438 | 0 | 0 | 0 |
Medial or lateral knee arthroplasty | 27446 | 0 | -1 | -1 |
Medial and lateral knee arthroplasty | 27447 | 0 | -1 | -1 |
Total | 29 | 149 | 190 | |
Return to OR | 4.53% | 23.28% | 29.69% |
aA -1 denotes No. <11 within the PearlDiver database, and exact numbers are not reported due to patient privacy considerations.
Abbreviations: ACI, autologous chondrocyte implantation; CPT, Current Procedural Terminology; OR, operating room.
Table 6. Rate of Return to OR Following OATS (n = 1320) | ||||
Procedure | CPT Code | 90 Days | 1 Year | 2 Years |
Knee arthroscopy | 29870 | 0 | 0 | 0 |
Knee arthroscopic drainage and lavage | 29871 | 0 | 0 | 0 |
Arthroscopic adhesions débridement | 29874 | 0 | 12 | 13 |
Arthroscopic synovectomy | 29875 | 0 | 0 | 14 |
Major arthroscopic synovectomy | 29876 | 16 | 25 | 28 |
Knee arthroscopic chondroplasty | 29877 | 17 | 58 | 78 |
Arthroscopic lysis of adhesions | 29884 | 0 | 0 | 0 |
Patellar arthroplasty | 27438 | 0 | 0 | 0 |
Medial or lateral knee arthroplasty | 27446 | 0 | 0 | 0 |
Medial and lateral knee arthroplasty | 27447 | 0 | 0 | 14 |
Total | 33 | 95 | 147 | |
Return to OR | 2.50% | 7.20% | 11.14% |
Abbreviations: CPT, Current Procedural Terminology; OATS, osteochondral autograft transplantation; OR, operating room.
Table 7. Rate of Return to OR Following OCA Transplantation (n = 1531) | ||||
Procedure | CPT Code | 90 Days | 1 Year | 2 Year |
Knee arthroscopy | 29870 | 0 | 0 | 0 |
Knee arthroscopic drainage and lavage | 29871 | 0 | 0 | 0 |
Arthroscopic adhesions débridement | 29874 | 0 | 15 | 19 |
Arthroscopic synovectomy | 29875 | 0 | 0 | 0 |
Major arthroscopic synovectomy | 29876 | 0 | 20 | 38 |
Knee arthroscopic chondroplasty | 29877 | 22 | 59 | 93 |
Arthroscopic lysis of adhesions | 29884 | 0 | 0 | 0 |
Patellar arthroplasty | 27438 | 0 | 0 | 0 |
Medial or lateral knee arthroplasty | 27446 | 0 | 0 | 0 |
Medial and lateral knee arthroplasty | 27447 | 0 | 0 | 22 |
Total | 22 | 94 | 172 | |
Return to OR | 1.44% | 6.14% | 11.23% |
Abbreviations: CPT, Current Procedural Terminology; OCA, osteochondral allograft; OR, operating room.
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