From the Department of Orthopaedics, Baylor University Medical Center, Dallas, Texas.

Corresponding author: Shawn Bonsell, MD, 411 N. Washington Street, Suite 7000, Dallas, Texas 75246.

Meniscus tear is a common associated finding in patients with an ACL injury. The goal of treating the meniscus tear is to preserve the meniscus by a repair or by performing a limited, partial meniscectomy (8). A meniscus repair or partial meniscectomy is thought to take extra operating room time and expense, since it may involve a second surgical incision and specialized operating room equipment.

Arthroscopic ACL reconstruction is a procedure that is well known to the nonmedical community, as the results and outcomes are often discussed openly in the media. Patients and physicians are subject to pressures for an optimum procedure, with return to unrestricted activity as quickly as possible.

With the financial pressures being placed on health care combined with the public pressure for a quality procedure, orthopaedic surgeons now have to justify their procedures based on a time, cost, and outcome analysis. This financial pressure is reflected in the increasing number of studies over the past 5 years dedicated to the cost analysis of ACL surgery. In 1995, Nogalski et al were the first to document the savings associated with shorter hospital stays (5). In 1996, Novak et al reported a >$7000 per case reduction in charges with outpatient ACL surgery compared with inpatient ACL surgery (9). They furthermore demonstrated a >$4000 per case charge reduction when the outpatient ACL surgery was performed at a separate surgical center, rather than the main hospital. Other studies have confirmed the financial savings associated with shorter hospital stays and outpatient surgery (10, 11).

Despite the increased awareness of the cost of ACL surgery, no study has yet documented the financial impact of different ACL grafting techniques. Furthermore, no study has analyzed the operating room time or cost influence of meniscus tears on ACL surgery. This study examines the financial analysis of 3 different areas of arthroscopic ACL surgery: outpatient vs inpatient surgery, meniscus tears, and ACL grafting techniques, specifically BPTB vs 4-strand hamstring.

METHODS

This study was conducted at Baylor University Medical Center in Dallas, Texas, a nonprofit hospital in a major metropolitan area, where approximately 150 ACL reconstructions are performed each year. Financial data for surgical procedures and admissions are categorized according to International Classification of Disease (ICD)-9 procedure codes and kept on a computerized data system. From this data system, a patient's medical record number, surgery performed, and length of admission can be retrieved. Furthermore, surgical cost and hospital charges can also be retrieved.

To have a meaningful study with valid statistical power, a sample size calculation was performed before the study to determine the number of cases needed for review (12). A 20-minute difference between procedures was defined as clinically relevant, as well as a $500 difference of surgical cost and a $1000 difference of hospital charges. The power for each of these effect sizes for these endpoints was specified to be at least 0.8. Variances from each parameter to be analyzed were estimated from a random sample of 50 ACL cases. From these values a sample size calculation with unequal size samples determined that no less than 256 BPTB cases, 28 hamstring cases, 50 meniscus repair cases, 70 meniscus debridement cases, 80 outpatient cases, and 80 inpatient cases would need to be reviewed for a statistically relevant study.

ICD9 procedure code number 81.45, “repair, other, ligament, cruciate,” was searched between June 1995 and October 1999 from the hospital database to capture 658 ACL cases from a similar economic era. The medical record, including the operative report and anesthesia record, of each ICD9 entry was then reviewed.

From the medical record, it was determined whether the ICD9 procedural code was correct, whether the patient had a primary endoscopic ACL reconstruction or not, and whether the BPTB or 4-strand hamstring technique was performed. Furthermore, it was recorded whether the patient had other concomitant procedures, including partial meniscectomy or meniscus repair, and the amount of time taken to perform the procedure.

A Student t test of independent samples was used to determine any difference between primary arthroscopic BPTB and hamstring ACL reconstruction procedures with regards to length of procedure, surgical cost, and hospital charges. A Student t test was also used to determine if cases with meniscus repair or debridement took longer or were associated with higher costs and charges and to determine cost and charge differences between outpatient and inpatient ACL surgery. Significance was defined at P < 0.05. Pearson's correlation coefficient was calculated to determine the relationship between length of procedure and operating room cost, as well as length of procedure and hospital charges.

DEFINITIONS

Operating room time: the amount of time taken to perform the procedure. This was the amount of time that elapsed between the anesthesiologist's start time and ending time, as recorded on the anesthesia time sheet for each case. This time includes transporting the patient to the operating room from the preoperative area, positioning and anesthesia, the actual surgery, and transportation to the postoperative recovery room.

Operating room cost: the hospital cost for a particular case. It includes a flat setup cost for opening the operating room, a cost for the supplies used, and a cost per minute of time in the room. Because of hospital confidentiality, actual operating room costs are not reported, but the relative differences in costs are.

Hospital charges: the fees billed to the patient or third-party payers. Hospital charges include a preoperative fee, a recovery room fee, and a daily fee if the patient spends >23 hours in the hospital. Both actual and relative hospital charges between hamstring and BPTB procedures are reported. Hospital charges also reflect a surgical fee from the hospital based on the operating room cost for each case. Individual surgeons' and anesthesiologists' professional fees are billed separately and are not included in either operating room cost or hospital charges.

RESULTS

Of the 658 ICD9 entries, 637 medical records were located. Twelve procedures were miscoded, and 100 procedures were not primary endoscopic BPTB or 4-strand hamstring ACL reconstruction or had other major concomitant procedures. The remaining 525 primary endoscopic ACL reconstruction procedures were reviewed.

Outpatient vs inpatient

In the analysis of outpatient vs inpatient ACL reconstruction, the 525 cases were divided into 3 groups: outpatient (246 patients), overnight admission (253 patients), and admission >1 day (26 patients with an average stay of 2.12 days).

Average outpatient operative time was 139 minutes, 21 minutes faster than cases with overnight admission (P = 0.001) and 42 minutes faster than cases with admissions >1 day (P = 0.001). Average outpatient operating room costs were $477 lower than average overnight admission operative costs (P = 0.001) and $1329 lower than the operative costs for those admitted >1 day (P = 0.001). Average outpatient hospital charges were $6822 per case, $870 lower than overnight admission charges (P = 0.001) and $2234 lower than the average admission charges for >1 day (P = 0.001).

Meniscus injury

Of the 525 cases reviewed, 273 cases (52%) had a meniscus tear. Of these 273 cases, 199 had a partial debridement (38% of total cases and 73% of cases with meniscus tears), and 74 had a repair (14% of total cases and 27% of cases with meniscus tears). No statistically significant difference was found in time or cost of ACL cases with partial meniscectomy or meniscus repair compared with cases without: meniscus debridement took 4.5 minutes longer and meniscus repair took 7 minutes longer than ACL cases without meniscus tears. There was a statistically significant, but financially small ($361), difference in hospital charges between cases with meniscus repair compared with those with no meniscus tear.

ACL techniques: BPTB vs hamstring

Of the 525 cases reviewed, 471 had BPTB grafts (90%) and 54 had 4-strand hamstring grafts (10%). Ten different surgeons performed the 525 procedures. Six surgeons performed exclusively the BPTB technique, 1 surgeon performed exclusively the hamstring technique, and 3 surgeons performed both techniques. However, 90% of the hamstring procedures were performed by 1 surgeon.

ACL reconstruction cases with BPTB took an average of 2 hours and 33 minutes, while cases with hamstring averaged 2 hours and 10 minutes. The 23-minute difference was statistically significant with P = 0.001.

Operating room costs for ACL reconstruction cases with BPTB were an average of $565 more expensive per case than ACL reconstruction cases with hamstring. This was statistically significant with P = 0.0001.

ACL reconstruction cases with BPTB averaged $7459 in hospital charges while ACL reconstruction cases with hamstring averaged $6444. The $1015 difference was statistically significant with P = 0.0001.

Of the 3 surgeons performing both BPTB and hamstring ACL reconstruction, only 1 surgeon performed >1 hamstring procedure. These surgeons' average case time for BPTB was 110 minutes, while their average case time for hamstring was 105 minutes. Their average operating room cost for BPTB was $560 more expensive, and the average hospital charges were $971 more expensive than for their hamstring reconstruction. However, no statistically significant difference was detected due to the small number of cases.

Among the 10 orthopaedists performing ACL reconstruction procedures, average case times varied from 110 minutes to 212 minutes (Figure 1). The lowest operating room charge was $1306 lower than the highest, and average hospital charges ranged from $6159 to $8665 (Figure 2). Shorter case times were positively correlated with lower operating room costs, r = 0.42, and lower hospital charges, r = 0.63. Lower operating room costs were positively correlated with lower hospital charges, r = 0.59.

DISCUSSION

Despite increased awareness of the costs surrounding ACL reconstruction, the financial effects of meniscus tears or of different ACL grafting techniques hadn't been previously evaluated. Prior studies have shown substantial savings with outpatient ACL surgery compared with inpatient surgery, but none of these studies reported or controlled for differences in operating room time, perhaps the single biggest factor in the cost of ACL surgery.

This study quantified the importance of operating room time in relation to the cost of and charges for ACL surgery. It showed that on average, a 23-minute faster ACL surgery produced more patient savings than did outpatient ACL surgery compared with an overnight admission ACL surgery. The hamstring technique had >$1000 per case savings compared with BPTB, whereas outpatient surgery only saved $870 per case.

In fact, if all ACL surgeries at our hospital were done with a 23-minute faster technique, 3450 operating room minutes a year could be saved--enough time for orthopaedic surgeons to perform 26 more ACL surgeries a year. Our hospital would save $85,000 per year in operating room costs and could bill an estimated $170,000 more with the amount of time saved. Patients and third-party payers would save an estimated $150,000 per year.

Reasons why the hamstring procedure might be >20 minutes faster compared with BPTB probably have to do with the harvest of the graft and the closure of the incision. Hamstring grafts can be harvested through a smaller incision that requires less dissection time and, most importantly, less time to close the incision. BPTB harvesting requires a longer incision, more dissection time to isolate the tendon-graft and cut bone plugs, and often a several layered closure of the wound at the end of the surgery. Other time differences between the 2 techniques are probably negligible. Both procedures require similar amounts of time for graft preparation, as well as tunnel placement and graft fixation.

A rather surprising finding of this study was the negligible financial impact of meniscus tears on ACL reconstruction. Concomitant meniscus repair or partial meniscectomy had no real influence on the overall time or expense of ACL reconstruction. This is a worrisome finding in the era of cost containment.

The long-term clinical benefit of meniscus preservation in ACL surgery is to decrease or even prevent osteoarthritis of the knee, but from the financial standpoint of ACL surgery in itself, the meniscus repair does not seem to be important. If this finding is confirmed with other studies, future third-party payers may not reimburse physicians for meniscus repair when done in conjunction with ACL reconstruction. If this happens, there could be a decreased incentive among orthopaedic surgeons to preserve menisci in ACL surgery. Proof of the long-term benefit of meniscus preservation needs to be well documented, with publicity directed toward physicians, patients, and third-party payers.

Several areas of caution are warranted in evaluating these data. First is the fact that anesthesia time, not surgical time, was used to reflect the length of an individual case. This time begins when the anesthesiologist sees the patient preoperatively and ends when the patient is transported to the postoperative recovery room. Although the average BPTB case was 2 hours and 33 minutes, actual surgical time was probably <2 hours. Using the anesthesia time was a necessity for this study, since it was the only consistently recorded entry in the medical record for the length of the case.

As more pressure is being applied for operating room efficiency, surgeons should take the responsibility for recording the actual surgical time in the operation note or dictation. This will eliminate nonsurgeon-related delay problems, such as anesthesia time and room turnover, which are currently considered part of the operation, and give a more accurate account of surgical time.

A second area of caution in the study relates to the differences in individual surgeons. There was a large variation in operating room times, costs, and charges among the orthopaedists in this study. Some of the surgeons worked by themselves, while others hired assistants or even hired personalized operating room teams, which may have influenced operating room times. Even among the BPTB and hamstring techniques, there were variations in the number of incisions used and fixation methods, with probable time differences.

Although this study demonstrated a time and financial difference between BPTB and hamstring, 90% of the hamstring grafts in this study were performed by 1 surgeon. In essence, we may be detecting a difference between surgeons rather than a difference between surgical techniques. The limitation of this study was the inability to sort out the surgeon effect from the type of procedure effect because only 1 of the 10 surgeons performed at least 2 cases of both ACL grafting techniques. These initial findings regarding these techniques would need to be studied more extensively in a larger group of surgeons who perform both types of procedures or would need to be evaluated more formally via random allocation.

A third area of caution concerns comparing this study with others. Hospitals have different financial structures (nonprofit, profit, academic, etc.) and processes (reporting actual or estimated costs, including or excluding professional fees).

Despite these cautions, this study examined a statistically significant number of patients and demonstrated differences in time, cost, and charges based upon surgical technique in ACL reconstruction. In the years to come, administrators will place more pressure on surgeons to perform cost-efficient surgery. We as physicians are placed in the difficult position of balancing what is best for our patients against what is most efficient for health care. If there is no proven difference in morbidity, mortality, or clinical outcome in ACL graft selection, then time and cost should be considered in our decision making.

This study demonstrated the importance of operating room time on the overall cost and charges associated with ACL surgery, as well as highlighted the relative lack of financial impact that a meniscus tear has on ACL surgery. This study also suggested that the 4-strand hamstring technique for ACL reconstruction may take less time, incur less surgical cost, and incur lower hospital charges than BPTB. Further studies with more surgeons performing hamstring grafts at our hospital and similar studies at multiple hospitals are needed for further validation.

Acknowledgments

I would like to thank Daniel Sexton and Dr. Robert W. Jackson for their assistance in this research.

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