ACL Reconstruction Rehabilitation Protocol

ORIGINAL ABSTRACT

Pain after arthroscopically assisted anterior cruciate ligament (ACL) reconstruction was examined during the first five postoperative days to evaluate its intensity and duration. Visual analog scales (VAS) and cumulative narcotic requirements were used to measure the intensity of pain.

One hundred consecutive patients who underwent arthroscopically assisted ACL reconstruction using a patellar bone-tendon-bone autograft by one of three surgeons at a single outpatient surgicenter were examined. Each received a standard general anesthetic. During surgery ketorolac (60mg) was given intravenously and 0.25% bupivicaine (1/2 cc/kg total) was injected into the joint space and the graft donor site. Following surgery all patients received scheduled doses of oral acetaminophen (650mg) and ketorolac (10mg) four times a day and were allowed to take oral oxycodone (5-10mg) every two hours as needed. Patients were instructed to complete a VAS score for pain while at rest and with attempted straight leg raising in the morning prior to rising. Cumulative narcotic consumption, VAS scores, and ability to perform straight leg raising were recorded on each of the first five postoperative mornings. Patients completed a satisfaction questionnaire at their one week postoperative visit.

All VAS pain scores are reported as means ± SEM. Pain scores reached a maximum at rest (4.8 ± 0.4) and with attempted SLR (6.5 ± 0.4) on the second postoperative morning. VAS scores did not diminish to a statistically significant degree until the fourth postoperative morning. Oxycodone consumption also peaked on the second day (16.0 ± 0.3 mgs). Ability to successfully perform a SLR was lowest on the second postoperative day. The five day cumulative mean for VAS while attempting SLR was significantly higher for patients unable to successfully perform SLR (5.8 ± 0.2) than for patients who were able to perform SLR (3.8 ± 0.3).

Eighty-nine percent of patients reported overall pain as mild or moderate, while ninety-five percent reported either excellent or good overall relief of pain.

In spite of apparent patient satisfaction the reported pain scores appear to indicate significant levels of pain following arthroscopically assisted ACL reconstruction, not peaking until the second postoperative day and persisting for the entire five day study period. The association between elevated pain scores and diminished ability to perform SLR suggests that pain may inhibit function and therefore early rehabilitation. Overall though, patients appear to be satisfied with oral analgesic outpatient management of pain following arthroscopically assisted ACL reconstruction.

 

INTRODUCTION

Open anterior cruciate ligament reconstruction (OACLR) is a painful procedure which, in the past, routinely required hospitalization for delivery of parenteral narcotics to provide adequate postoperative analgesia. Arthroscopic anterior cruciate ligament reconstruction techniques appear to dramatically decrease tissue trauma and resultant pain. In addition, the recent clinical application of the concept of multimodal analgesia has greatly improved our management of pain.^8,3

With the application of these techniques and concepts arthroscopically assisted ACL reconstruction is now performed as an outpatient procedure with apparently good control of pain. To date, however, there have been few studies in the literature which have rigorously examined the intensity of pain and analgesic use after arthroscopically assisted ACL reconstruction for more than 24 hours.

Poorly managed pain may inhibit the early ability to mobilize joints which may in turn result in adhesions, cartilage resorption and ulceration, capsular and pericapsular contracture, fibrofatty proliferation within the joint, weakened ligament insertion, muscle atrophy, and osteoporosis ¹ all of which may delay or permanently impair the ultimate functional outcome¹¹. Although such conditions are rare they can occur following arthroscopically assisted ACL reconstruction.

The purpose of this study was to examine analgesic consumption and the intensity of pain and its effect on the patient's ability to perform straight leg raising following arthroscopically assisted ACL reconstruction over the first 5 postoperative days.

 

MATERIALS AND METHODS

Patient Selection

With internal review board approval we prospectively examined 100 consecutive patients who underwent arthroscopically assisted ACL reconstruction on an outpatient basis from November 1992 to June 1993.

Surgical Technique

Arthroscopically assisted ACL reconstruction was performed using a bone- patellar tendon-bone autograft. The graft was harvested through a vertical anterior incision. The remainder of the procedure, including concomitant meniscectomy or meniscal repair (if necessary), was performed arthroscopically. Meniscus repairs were facilitated with auxiliary posterior incisions. After appropriate preparation of the intercondylar notch, the graft was positioned "isometrically" and fixed in place with interference fit screws adjacent to the bone blocks in both the femoral and tibial tunnels. The femoral graft fixation was done from "inside out".

After all appropriate intra-articular surgery was completed, the defect in the patellar tendon where the graft had been harvested was closed with sutures, and the patellar bone block site was packed with cancellous autogenous bone graft obtained when the tibial drill hole was made. Hemovac drains were placed in the joint and subcutaneous space before closing. A tourniquet was used during the entire procedure and released after application of the dressings. A pneumatic cryocuff (Cryo/Cuff® Air Cast, Summit N.J.) which was applied immediately after the procedure, was used for intermittent cryotherapy and compression for the 5 day study period. Intermittent passive range of motion was begun in the recovery room using a continuous passive motion device (Kinetic^TM, Smith and Nephew Richards, Memphis Tenn.) and continued for two hour periods three times a day was also used for 5 days.

Anesthetic Technique

The anesthetic technique was standardized. Premedication and intraoperative narcotics were routinely omitted. Anesthesia was induced with propofol and maintained with isoflurane. Muscle relaxation and intubation were performed at the discretion of the anesthesiologist.

Pain Management

Patients were asked to take acetaminophen (650mg) by mouth four times a day beginning the morning before surgery. Ketorolac (60mg), was given IV following induction and prior to tourniquet inflation. Before the incision was made 0.25 ml/kg of 0.25% bupivicaine with epinephrine was injected subcutaneously at the expected puncture and incision sites. Another 0.25 ml/kg of 0.25% bupivicaine with epinephrine was injected intra-articularly at the same time. These injections were repeated, with the same volumes of 0.25% bupivicaine with epinephrine, at the completion of surgery, just prior to release of the tourniquet. Thus, the total dose of 0.25% bupivicaine with epinephrine for each patient was 1ml/kg. A pneumatic Cryocuff was applied immediately after the procedure, and was used for intermittent cryotherapy and compression for the first 5 postoperative days. In the recovery room, patients with severe pain (defined as visual analog scale scores of 5 or greater) were given IV fentanyl citrate. All others were allowed 5 to 10mg oxycodone by mouth as needed. Following discharge, patients were instructed to take both ketorolac (10mg) and acetaminophen (650mg) by mouth four times a day for five days. In addition, patients were instructed to take 5 to 10 mg of oxycodone every two hours if they experienced any pain at rest or greater than minimal pain with activity.

Pain Measurement

All patients were instructed before surgery on the use of an 11-point box scale, a visual analog scale (VAS), the advantages of which have previously been described⁶. A VAS was obtained verbally on arrival to, and at discharge from, the recovery room. The incidence and dose of fentanyl citrate requirements were recorded. After discharge, patients were asked to complete a VAS while at rest and another VAS after attempting a straight leg raising maneuver on awakening on each of the first 5 postoperative mornings. The maneuver was considered successful if the foot was elevated off the bed. In addition, patients were asked to record the number of oxycodone tablets they consumed on each of the first 5 postoperative days. Questionnaires requesting this information were returned at the one week post-op visit, at which time subjects were asked to complete a questionnaire on patient satisfaction.

Satisfaction Assessment

At the 1 week follow-up visit, all patients were asked on the questionnaire to rate their overall pain experience (none, mild, moderate, or severe) and their degree of satisfaction with the management of their pain (excellent, good, adequate, or poor).

Statistical Analysis

All data are expressed as either mean ± SEM or percentiles as appropriate. Statistical analysis was performed using StatView software (Abbacus Concept, Inc., Berkeley, CA 192) on a computer (Macintosh, Apple Computers, Cupertino, CA). Pain scores were analyzed using repeated measure analysis of variance. Effects of time and activity were tested. Post-hoc comparisons were performed with Fisher's PLSD test. Daily mean pain scores were grouped by ability to perform straight leg raises and compared using unpaired t tests. P values <0.05 were considered significant.

 

Results

Demographic Data

The age of the patients was 26.5 ± 8.7 years (mean ± SEM). Total operating room time was 128.3 ± 1.8 minutes and tourniquet time was 90.5 ± 2.1 min. Total time in the post anesthesia care unit was 142.3 ± 4.0 minutes. There were 54 men and 46 women. Eighty (80%) patients returned completed daily questionnaires and 60 (60%) participants completed the questionnaires on patient satisfaction.

Pain Measurements

The VAS scores were 1.0 ± 0.21 immediately after the patient was brought to the post anesthesia care unit, and 2.4 ± 0.21 at the time of discharge from the unit. Only 10% of the patients received IV fentanyl citrate in the unit, which was given only if they verbally reported pain scores of 5 or greater. The mean dose of fentanyl citrate given was 55.0 ± 12.9 mg. Visual analog scores at rest and with straight leg raising (active) for each of the first 5 postoperative mornings are displayed in Figure 1. The mean score for each peaked on the second postoperative morning. Mean daily narcotic consumption is displayed in Figure 2. Peak consumption occurred between 24 and 48 hours after surgery (16.0 ± 1.7 mg oxycodone (equivalent to 8.8 mg parenteral morphine sulfate). Mean consumption for the entire five postoperative days was 53.0 ± 5.2mg of oxycodone (equivalent to 8.8mg of parenteral morphine sulfate).

Functional Assessment

The frequency (in percentages) of successful straight leg raising is displayed in Figure 3. The lowest frequency occurred on the 2^nd postoperative morning, which coincides with the period of highest pain scores and greatest oxycodone consumption. Figure 4 shows the mean daily VAS scores, grouped by ability to perform straight leg raises. The differences in pain scores between groups were significant on each day (p>0.05).

Satisfaction

Patient perception of overall postoperative pain and its management are displayed in Figures  5 and 6.

Discussion

Both the level of pain measured by VAS and the amount of narcotics consumed peaked on the 2^nd postoperative day. There was no statistically significant diminution of either measure until the fourth postoperative day. The course of pain reported at rest and with activity (defined as attempted straight leg raise) were similar to each other, however, the magnitude of pain reported with activity was consistently greater than at rest. Although the VAS scores were indicative of a moderate degree of pain, and patients in this study categorized the entire postoperative pain experience as mild to moderate, the actual consumption of narcotic analgesics was modest, and the same patients reported a high degree of satisfaction with the perioperative pain management. The rate of return for the daily pain questionnaire is relatively low for a prospective study. This may be attributed to the fact that it was completed by patients themselves on a daily basis for five consecutive mornings. However the likelihood of return bias in the daily reporting of VAS or analgesic consumption is low. These are objective measures without direct subjective implications about care givers that might be expected to induce a systematic reporting bias by dissatisfied patients.

Anonymous surveys have a greater tendency to reveal dissatisfaction. Thus the high degree of satisfaction is probably accurate as well. There has been no prior report of pain following arthroscopically assisted ACL reconstruction in outpatients measured over a 5 day period. However, two prior studies of pain after ACL reconstruction examined only the first 24 hours following surgery^7,9 and a third study examined only up to 48 hours¹⁰. The findings of the present study imply that examining only a 24 hour period of time may lead to erroneous conclusions about the patients' overall pain experiences and the effectiveness of analgesic strategies. Future studies of pain following arthroscopically assisted ACL reconstruction should consider both the prolonged duration and greater degree of pain with activity.

The pain management protocol employed in this study is an oral regimen predicated on the principle of multimodal pain management. Previous reports of pain following open ACL reconstruction have examined the use of intravenous PCA (patient controlled analgesia), epidural narcotics, and femoral nerve sheath infusions with local anesthetics^9,10,12. Neither epidural narcotics nor continuous nerve blocks are readily available for outpatient use, and both of these involve significant risk and cost compared to an oral regimen such as that used in this study. Although intravenous PCA has been used in the outpatient setting, it also is more costly and invasive than an oral regimen. Because these patients required small amounts of narcotics, PCA would not seem to be warranted.

Multimodal analgesia refers to the concurrent use of multiple analgesics that operate through different mechanisms^8. It is presumed that the analgesic effects are additive, allowing improved pain relief with smaller doses of each drug, thereby limiting the side effects associated with each class of analgesic. The use of multimodal analgesia has been shown to provide superior pain relief with fewer side effects than unimodal regimens³. In addition cryotherapy may have further enhanced the effectiveness of the oral analgesic regimen^5,12. Intra-articular morphine sulfate was not used in these patients, although there is a report that shows significant benefit from this treatment in the first 24 hours after surgery⁷. The use of intra-articular morphine sulfate may prove to be a useful adjunct to this multimodal regimen.

The percentage of patients able to perform straight leg raises was lowest on the 2^nd postoperative day, which correlates with the period of greatest pain scores and narcotic consumption. The pain scores reported by patients unable to perform straight leg raises were significantly higher than those reported by patients able to straight leg raises on each postoperative day. The straight leg-raising maneuver was chosen as a reliable and easily interpreted task to elicit activity related pain. The association between elevated pain scores and diminished ability to perform straight leg raises suggests that pain may inhibit volitional knee movement and may therefore inhibit early knee mobilization, ambulation, and rehabilitation. Earlier ability to mobilize the knee following surgery, in turn, may limit or prevent deleterious effects of surgery and joint immobilization such as intra-articular adhesions, articular cartilage trophic changes, and muscle atrophy^1,2,4,12. Early ability to ambulate and participate fully in physical therapy may shorten the time to functional autonomy and return to work⁶, as well as the total cost of physical therapy. There is a clear association between reported pain intensity and the ability to perform SLR in this study. Improved pain relief may therefore be an important element in earlier functional recovery following arthroscopically assisted ACL reconstruction.

 

CONCLUSIONS

The pain experienced after outpatient arthroscopically assisted ACL reconstruction is significant, persisting for several days and possibly affecting functional abilities. Improved pain relief during this period may improve the early ability to perform straight leg raises and return to normal activity. Patients rated their overall pain experience as mild to moderate, and expressed a high degree of satisfaction with its management using an oral regimen on an outpatient basis.

 

Address correspondence and reprint requests to Douglas W. Brown, MD, PO Box 1260, 33 Sewall Street, Portland, ME 04104-1260

No author or related institution has received any financial benefit from research in this study.

 

REFERENCES

1. Akeson WH, Amiel D. Abel MF, et al: Effects of immobilization on joints. Clin Orthop 1987;219:28-37.

2. Butler DL, Noyes FR, Grood ES: The effects of vascularity on the mechanical properties of primate anterior cruciate ligament replacements. Trans Orthop Res Soc 1983;8:93.

3. Dahl JB, Kehlet H: Non-steroidal anti-inflammatory drugs: rational for use in severe postoperative pain. Br J Anaesth 1991;66:703-712.

4. Enneking WF, Horowitz M: The intra-articular effects of immobilization of the human knee. J Bone Joint Surg 1972;54A:973-985.

5. Fetrow KO: The management of Pain in Orthopedics. The Clinical J Pain 1989;5:S26-S34.

6. Jensen MP, Karoly P, Eoghan FO, et al: The Subjective Experience of Acute Pain: An Assessment of the Utility of 10 Indices. The Clin J Pain 1989;5:153-159.

7. Joshi GP, McCarroll SM, Brady OH, et al: Intra-articular Morphine For Pain Relief After Anterior Cruciate Ligament Repair. Br J Anaesth 1993;70:87-88.

8. Kehlet H: Surgical Stress: The role of pain and analgesia. Br J Anaesth 1989;63:189-195.

9. Loper KA, Ready LB: Epidural Morphine After Anterior Cruciate Ligament Repair: A Comparison with Patient-Controlled Intravenous Morphine. Anesth Analg 1989;68:350-352.

10. Matheny JM, Gregory BS, Hanks A, et al: A Comparison of Patient-Controlled Analgesia and Continuous Lumbar Plexus Block After Anterior Cruciate Ligament Reconstruction. Arthroscopy, 1993;9(1):87-90.

11. Moffet H, Richards CL, Malouin F, et al: Early and Intensive Physiotherapy Accelerates Recovery Following Postarthroscopic Meniscectomy: Results of a Randomized Controlled Study. Arch Phys Med Rehabil 1994;75:415-426.

12. Noyes FR, Torvik PJ, Hyde WB, et al: Biomechanics of ligament failure. II. An analysis of immobilization, exercise and reconditioning effects in primates. J Bone Joint Surg 1974;56A:1406-1418.

13. Shelbourne KD, Rubinstein RA, McCarroll JR, et al: Postoperative Cryotherapy for the Knee in ACL Reconstructive Surgery. Orthopedics International Edition 1994;2:165-170.