Accelerated rehabilitation after arthroscopic meniscal repair: A clinical and magnetic resonance imaging evaluation

Accelerated Rehabilitation After Arthroscopic Meniscal Repair: A Clinical and Magnetic Resonance Imaging Evaluation Pier Paolo Mariani, M.D., Nicola Santori, M.D., Ezio Adriani, M.D., and Marco Mastantuono, M.D.

Summary: Twenty-two patients who underwent meniscal repair using the outsidein technique combined with anterior cruciate ligament (ACL) reconstruction were submitted to an accelerated rehabilitation protocol that included immediate full range of motion and weightbearing. The patients were reviewed postoperatively by means of clinical assessment and magnetic resonance imaging (MRI) after an average of 28 months. Clinical evaluation was performed according to the International Knee Documentation Committee form, and sagittal knee laxity was measured with a KT-2000 arthrometer (MedMetric Corp, San Diego, CA). The MRI scans were obtained using a 0.2-T high-resolution MRI unit dedicated to the study of limbs, and the meniscal signal was graded according to a modified Crues classification. Overall, 77.3% of patients reported clinically good results. Loss of extension of <5 ° was detected in only 2 patients (9.1%). Three out of 22 patients showed clinical signs of meniscal retear. One of these patients had a second operation for a bucket-handle tear. The presence of a full-thickness rim at MRI evaluation, present in 10 patients (45.5%), did not correlate with the presence of clinical symptoms of retear. Instead, the 3 symptomatic patients presented a complete rim with a gap > 1 mm between the meniscal wall and the fragment of the posterior horn. This finding is believed to be a more reliable indicator for retear following meniscal repair. The low failure rate in this series suggests that an aggressive rehabilitation regimen may be prescribed without deleterious effects in subjects undergoing ACL reconstruction and concomitant meniscus repair. Key Words: Meniscus repair--Arthroscopy--Rehabilitation--MRI--Knee joint.

he difficulty in regaining full range of motion after surgical repair of the anterior cruciate ligament (ACL) is well known. To minimize this complication, an accelerated rehabilitation regimen has recently been adopted by some orthopaedic surgeons. 1 However, there are some biological restrictions to this aggressive protocol, such as a concomitant acute capsular injury or meniscal tear suitable to repair. In fact, to protect

T

From the I Clinica Ortopedica (P. P. M., N.S., E.A. ) and H Dipartimento di Radiologia (M.M. ), Universit& "La Sapienza, " Rome, Italy. Address correspondence and reprints requests to Pier Paolo Mariani, M.D., Clinica Ortopedica Universit& "La Sapienza," Piazza Aldo Moro 5, 00185 Rome, Italy. © 1996 by the Arthroscopy Association of North America 0749-8063/96/1206-142753.00/0

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meniscal healing after repair, many surgeons have opted for less aggressive rehabilitation. Weightbearing, joint motion and pivot activities are often restricted, even though a general consensus is lacking on how long these should be delayed. Some authors advocate immobilization, 2-6 partial weightbearing, or both, in the first 4 to 8 weeks postoperatively. 7-11 Immobilization m a y be carried out at full extension 4'12a3 or at various degrees of flexion. 2'3'5"83°'14Restricted joint motion and weightbearing after a concomitant meniscal repair may increase the risks o f arthrofibrosis following A C L surgery. 15-19However, some authors 2°-23have recently proposed more aggressive rehabilitation without reporting deleterious effects. In 1988, Henning et al. 22 advocated immediate knee motion and early partial weightbear-

Arthroscopy: The Journal o f Arthroscopic and Related Surgery, Vol 12, No 6 (December), 1996: p p 680-686

MENISCAL REPAIR AND REHABILITATION ing, whereas full weightbearing is proposed by Noyes et al. 23 and Barber. 2° The purpose of this study was to assess by clinical and magnetic resonance imaging (MRI) evaluation the safety of an accelerated rehabilitation regimen following meniscal suture and concomitant ACL reconstruction.

MATERIALS AND METHODS The following inclusion criteria were established for this prospective study: (1) chronic ACL insufficiency with an injury-to-surgery interval of more than 6 months, (2) longitudinal tear of the medial posterior horn in the vascular periphery, (3) tears longer than 1 to 1.5 cm, and (4) use of the same postoperative protocol at the same center under the supervision of a single member of the staff. Exclusion criteria were (1) a history of meniscal lesions in the controlateral knee, (2) posterior, medial or lateral laxity, and (3) lateral meniscal lesions. From 1989 to 1991, 22 patients met the above criteria. These patients were operated on by a single surgeon for chronic ACL lesion and for medial meniscus tear. Mean age of the patients was 23 years (range, 17 to 38 years). The group consisted of 16 men and 6 women with 16 subjects having injury to the right knee and 6 to the left knee. All subjects underwent arthroscopically assisted ACL reconstruction with bone-tendon-bone patellar autograft using the one-incision technique. The meniscal tear was repaired using the outside-in technique with an 18-gauge spinal needle placed across the tear from the outside. A knottedend suturing technique 24'25 was performed using a 2-0 PDS suture. The perimeniscal synovial membrane and the meniscal wall were thoroughly abraded with a rasp. Sutures were placed before ACL surgery and tied at the end of the ligamentous procedure. Postoperatively, the patients followed the normal accelerated rehabilitation protocol that we apply even in the absence of meniscal repair. This involves continuous passive motion from 0 ° to 90 ° starting the second day after surgery and continues for 2 weeks with full weightbearing as soon as tolerated. Immobilization in a knee brace locked at 0 ° flexion is prescribed during deambulation for the first month only. The use of a brace is discontinued as the patient learns to walk with a straight knee. Two to 4 weeks after surgery, workouts are supplemented with closed kinetic chain exercises, low-resistance stationary cycling, and swimming. Progressive resistance exercises are started 4 weeks postoperatively. Running and biking are allowed after 2 months, and after a Cybex evaluation, tennis is allowed

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after 3 months. Unrestricted return to training of pivoting activities is permitted at 5 months and return to agonistic sports without a functional brace is allowed at 6 months. Patients were evaluated both clinically and with MRI at an average of 28 months (range, 24 to 32 months). Preoperative and postoperative evaluation included assessment of clinical status with recordings of knee instability and meniscal pathology. The information collected included acute or chronic status, length of tear, and demographic and historical data. Physical examination included presence of effusions, joint line tenderness, range of motion, meniscal signs, (McMurray's and grinding tests), ligamentous signs (Lachman test, pivot shift). Sagittal knee laxity was measured with a KT-2000 arthrometer (MedMetric Corp, San Diego, CA). All patients were evaluated using the International Knee Documentation Committee (IKDC) form that includes 8 different groups of evaluation: patients subjective assessment of function and symptoms, range of motion, laxity, presence of crackling, symptoms at the site of graft harvesting, radiographic findings and functional evaluation. Each group includes several questions and the answers are classed as A (normal), B (nearly normal), C (abnormal), or D (severely abnormal). The worst answer determines the final result of the group and the final overall result is given by the worst score obtained in the first four groups. The MRI scans were obtained using a high-resolution unit utilizing a permanent ferrite magnet, designed for the study of the extremities. Magnetic field intensity was 0.2 T; gradient intensity 10 mT/m, and field of view 16 cm. Coronal sagittal and axial images were taken in all cases. Spatial resolution of 0.6 mm was achieved by using 2- to 3-ram section thickness with no intersection gap and 192 × 256 matrix acquisition. Sequences used were SE T1 TR 680 TE 24 m/s and SE T2 TR 2000 TE 90 1-n/s. Sagittal images in flexion and full extension were acquired using a special device that guides the joint in standardized planes of movement. The MRI scans were independently evaluated by an expert muscoloskeletal radiologist (M. M.) who was blinded to the clinical data.

RESULTS There were no significant intraoperative or postoperative complications in this group of patients. The results were evaluated at follow-up by a single independent examiner (N. S.). Results of the IKDC evaluation are summarized in Table 1.

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TABLE 1. Postoperative Assessment According to IKDC Knee Ligament Evaluation Form IKDC Categories A B C D

1

2

3

4

5

6

7

8

10 45.4% 8 36.4% 2 9.1% 2 9.1%

15 68.2% 6 27.3% 1 4.5% 0

20 90.8% 2 9.1% 0

12 54.5% 8 36.4% 2 9.1% 0

21 95.4% 1 4.5% 0

12 54.5% 8 36.4 2 9.1% 0

10 45.4% 10 45.4% 2 9.1% 0

21 95.4% 1 4.5% 0

0

0

0

NOTE. 1, subjectiveclinical outcome; 2, pain, swelling, giving-way; 3, range of motion; 4, ligament examination; 5, articular crepitism; 6, pain at site of graft harvest; 7, radiographic alterations; 8, one-leg hop.

Subjective Clinical Outcome

Ligament Examination

The subjective clinical outcome is considered in the first group of the IKDC form and the score is determined by two questions: " H o w does your knee function?" and " H o w does your knee affect your activity level on a scale from 0 to 3?" On this section, 10 patients (45.4%) scored A and 8 patients (36.4%) scored B, 2 patients (9.1%) scored C and 2 (9.1%) scored D. The high incidence of poor results in this section is mostly due to the second question, because the patients, although satisfied with the surgical outcome, experienced some reduction of their activity level.

All 22 knees appeared stable both clinically and at the instrumented measurements. Twelve patients (54.5%) scored A, 8 (36.4%) scored B, and 2 scored C (9.1%) in Group 4 of the IKDC form, which deals with knee stability. Anterior stability measured with the KT-2000 arthrometer showed that the preoperative average side-to-side differences at 30 lbs was 7.2 (+2.3) mm and at follow-up became 1.9 (+ 1.6) ram. The side-to-side differences at manual maximum were on average 7.0 mm preoperatively. The postoperative side-to-side differences were < 3 mm in 16 cases and between 3 and 5 mm in the remaining 5 cases with an average of 1.5 mm at follow-up. The pivot shift test was negative in 20 patients (90.9%) and a glide was detected in the other 2 patients (9.1%). In the 3 patients with signs of medial meniscus pathology, knee stability was recorded as good both at clinical examination and with the KT-2000 arthrometer. We did not find any relationship between knee stability and recurrence of tear. Sections 5 through 8 of the IKDC form are not mandatory for the final result, but these are nonetheless reported in detail in Table I. In section 5, which concerns articular crepitism, only 1 patient had moderate patellofemoral crepitism but without pain. In section 6 (pain at the site of graft harvest) 12 patients (54.5%) had no pain, 8 had (36.4%) mild discomfort, and 2 (9.1%) had moderate pain. None of the patients reported severe pain. In section 7, radiographic alterations, 10 patients (45.4%) showed no side-to-side difference; 10 patients (45.4%) showed minor alterations, always in the medial compartment; and 2 patients (9.1%) showed moderate alterations, one in the medial and the other in the lateral compartment. Section 8 records side-to-side difference in performing the oneleg hop, and all patients but 1 were able to jump without restrictions. At the 2-year follow-up IKDC evalua-

Symptoms Three out of the 22 patients of this series complained of symptoms of medial meniscus disorder. One of the patients had a second operation, and a bucket-handle tear was found at arthroscopy. The other 2 patients refused an arthroscopic second-look for their meniscal complaints. The meniscal tests were positive in these 3 patients and negative in the other 19 patients. Only 1 patient had a knee effusion, and this was the patient who was operated on later for removal of a buckethandle tear. In terms of pain, swelling, and giving-way, following the IKDC parameters, 15 patients (68.2%) scored A, 6 patients (27.3%) scored B, and 1 patient (4.5%) scored C. The pain was reported during sport activities and only in 1 during activities of daily life. Five of these patients had pain localized at the anterior aspect of the knee or at the patellar tendon defect.

Range of Motion Full extension ( < 5 °) was restricted in only 2 subjects (9.1%), and reached the anatomic zero position in the others. Flexion deficit was not detected in this series. All in all, 20 patients (90.8%) scored A in Group 3 of the IKDC, and 2 patients (9.1%) scored B.

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TABLE 2. Final Evaluation According to IKDC Knee Ligament Standard Evaluation Form IKDC Final Evaluation

Group A

Group B

Group C

Group D

Pazienti (%)

2 (9.1%)

15 (68.2%)

3 (13.6%)

2 (9.1%)

tion, 9.1% of the patients were in group A, 68.2% in B, 13.6% in C, and 9.1% in D (Table 2). MRI Evaluation We graded the MRI of the posterior meniscal horn according to a modified Crnes classification. 26 In grade 0, the posterior meniscal horn has a homogeneous lowsignal-intensity structure; in grade 1, an incomplete rim extends to only one of the meniscal surfaces; in grade 2, a complete rim is present at the site of the previous tear, which appears as a line of high signal intensity through a full-thickness defect but without diastasis; in grade 3, a complete rim with a gap greater than 1 mm (Figs 1 and 2) is present. In Crues' original classification, the grade 3 signal correlates poorly with the existence of retears following meniscal repair, 27 and for this reason in our classification we consider the presence of diastasis as predictive of retear. The possibility of obtaining images in both flexion and extension may be useful to determine the stability of a previously repaired meniscus when a full-thickness high signal is present. In our MRI analysis we observed that the gap increases in full extension when an unstable meniscal tear is present, probably because the posterior capsule pulls the posterior horn. In terms of MRI, we found overall satisfactory results in 86.4% of our patients. Using the modified classification, 6 patients (27.3%) fell into group 0, 3 patients (13.6%) into group 1, 10 patients (45.5%) into group 2, and 3 patients (13.6%) into group 3. We observed a gap between the meniscal wall and posterior horn fragment in all 3 symptomatic patients. Average diastasis in group 3 was 2.2 mm (range, 1.4 to 3 ram).

y e n , 29 5 weeks by Ryu and Dunbar, ~° and 3 weeks by McLaughlin et al. 21 Other surgeons propose early partial weightbearing. 7-11 Similar disagreement can be found for joint motion and return to pivoting activities, with resumption after 4, 6, or more than 6 months. The various postoperative regimens have shown minor to significant differences, and the as yet poorly understood healing rates of meniscal repairs have led the surgeons to suggest various restrictions. Experimental studies show that lesions of the vascular portion of the meniscus heal completely after 10 weeks and that it takes several months for the return of normal appearance fibrocartilage. 3° Four to 5 weeks are usually required for early histological evidence of meniscal re-

(

I

DISCUSSION The literature describes a variety of rehabilitative protocols after meniscal suture. In an attempt to protect the repaired meniscus, many surgeons advocate restricted weightbearing and knee motion or immobilization. Immobilization is recommended in full extension by some, 4'12'~3 or in various degrees of flexion by others. 5-8'1°'28 Full weightbearing is postponed for various amounts of time: 8 weeks by Scott et al. 5 and Della-

FIG 1. Classification of the appearance of the posterior meniscal horn on MRI following meniscal repair. (A) The meniscal horn completely healed (grade 0); (B) an incomplete rim (grade 1); (C) a complete rim at the site of a previous tear (grade 2); (D) a rim with diastasis (grade 3).

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FIG 2. MRI of a posterior horn after meniscal repair. (A) Grade 0; (B) grade 1 with an incomplete rim; (C) grade 2 with a complete rim in an asymtomaticpatient; (D) grade 3 with diastasis within the scar of a previous repair.

pair. Zhongnan et al. 31 in their experimental study on rabbits reported that an acute tear may heal by simply immobilizing the knee without the need to suture the lesion. On the other hand, Kawai et al. 32 conclude that postoperative immobilization may not be necessary for meniscal healing. The optimum rehabilitation regimen has yet to be identified, and the lack of scientific data in the literature does not allow us to endorse a specific rehabilitation program. Recently, in an attempt to restore normal knee function as early as possible, some authors have carried out a more aggressive rehabilitation protocol 2°~23 without deleterious consequences for meniscal healing. McLaughlin et al. 21 reported an 80% success rate after an aggressive rehabilitation in patients undergoing concurrent meniscal repair and ACL reconstruction. Barber 2° did not find statistically significant differences between two groups of patients with restricted and unrestricted postoperative regimens. In both studies, clinical evaluation was carried out at follow-up. Bu-

seck and Noyes 33 carried out arthroscopic evaluation after an aggressive rehabilitation regimen following meniscal repair in conjunction with ACL reconstruction. They found that 80% of meniscal repairs healed completely, 14% healed partially, and 6% failed. Different methods have been used to evaluate the success of a meniscal repair. Clinical evaluation alone is not reliable because of the presence of many asymptomatic retears. Instead, the evaluation of previously sutured meniscus tears by arthrography 34 has given results of better than 90% of accuracy. Arthography has thus become the gold standard in the evaluation of repaired menisci. However, there are obvious drawbacks in prescribing arthrography in healthy patients after ACL surgery. The same problems are encountered with arthroscopy, which is also poorly accepted by patients when the sole justification for its use is simply to document healing. Moreover, although both these techniques evaluate the continuity of the meniscal surface, they do not allow direct evaluation of inter-

MENISCAL REPAIR AND REHABILITATION

nal meniscal structure. On the other hand, MRI can display abnormal internal signals regardless of the state of the surface. Although the use of MRI has been less compelling for the postoperative follow-up of meniscal repair, it remains a practical method of evaluation. A potential pitfall of MRI is the persistence postoperatively of meniscal signal abnormalities, which may be confused with meniscal retear. The increase in signal intensity with T2 weighted images has been reported as an important predictive finding; however, it has only 60% sensitivity. Although complete healing might be expected to restore a normal signal, corresponding to that from a homogeneous meniscus, if the meniscus heals with fibrovascular scar tissue, signal abnormalities will appear on images during the healing period. Kent et al. 35 showed the persistence of signal abnormalities in sutured menisci 6 months after surgery. Further, Arnoczky et al. 36 in their experimental study show that repaired issue yields an increased MRI signal after 26 weeks, even though the tissue had modulated from fibrovascular scar tissue into fibrocartilage. Clues et al) 6 reported that when considering only grade 3 signal intensity on MRI as consistent with meniscal tear, the scans agreed with surgical findings in 91% of cases. However, several reports 27'37-39 now indicate that evaluation of menisci that have undergone surgery is less reliable or specific when the diagnosis of a retear is carried out solely by the presence of a linear signal intensity (grade 3). Moreover, LaPrade et al. 4° have recently shown an incidence of asymptomatic tear (1.9%) or grade 2 signal (24.1%) in a series of young asymptomatic patients. The only MRI finding accurately predictive of retear in a previously sutured meniscus is the presence of diastasis within a linear signal intensity extending to the articular meniscal surfaces. Evaluation of acquired sagittal images in flexion and in full extension, using specialized equipment, is also important diagnostically. Using this method, it is possible to differentiate, in a previously sutured meniscus, a high signal intensity within the meniscal scar from a hyperintense signal due to diastasis; only the latter is a sure sign of retear. This last result was the only finding in our MRI examinations strongly consistent with the clinical history of our 3 symptomatic patients. Evaluation of the cases that showed linear signal intensity without diastasis is more uncertain because all these patients had neither complaints nor symptoms. Here, however, even if we cannot be certain of meniscal healing, the meniscus seems clinically stable and functionally valid. Many experimental studies 35'36 confirm that MRI signal abnormalities after meniscal suture are quite common but

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no evidence exists on the meaning and evolution of these findings. More long-term studies and control group studies would be useful to better understand the real meaning of these MRI signal abnormalities. The overall incidence of treatment failure of the meniscal suture reported in the literature is confusing, ranging from 4% to 25%. This variability depends on different factors, such as the type of lesion (central or peripheral, acute or chronic tears, isolated or associated with ACL lesion), the technique used, the suture type and, lastly, the assessment method (clinical, arthrographic, arthroscopic). According to anatomic assessment, our failure rate after accelerated rehabilitation was similar to that reported in the literature for similar types of meniscal tears. Our results show a successful clinical outcome in 19 out of the 22 repaired menisci at 2-year follow-up. We should point out that this group included only cases with slight restriction of extension, with an average loss of 3.5 °. In the literature, the incidence of arthrofibrosis after concomitant ACL surgery and meniscal repair is reported to be high, ranging from 10% 19 to 19%. TM Moreover, the incidence of extension deficit is even higher, whereas our results from following a more aggressive postoperative regimen showed a very low incidence of restricted range of motion. CONCLUSIONS Accelerated rehabilitation after meniscal repair appears to be safe, and the incidence of retears evaluated clinically and by MRI assessment is in line with those reported in the literature. If meniscal suture is performed in conjunction with ACL reconstruction, an accelerated rehabilitation regimen helps prevent arthrofibrosis, a well-known complication of major ligamentous reconstructive procedures. The reliability of MR1 in evaluating meniscal suture outcome is controversial. We have found that only a complete rim with a gap within the meniscal rim has a predictable chance of retear. MRI evaluation of the knee performed in flexion and extension may detect this finding. Some doubts still remain in a Crues grade 2 finding. We did not find any correlation between the presence of a complete rim and patient symptomatology. In this case, it would be more useful to perform arthrography or arthroscopy to evaluate the meniscal healing. REFERENCES 1. ShelbourneKD, Wilckens JH, MollabashyA, DeCarlo M. Arthrofibrosis in acute anterior cruciate ligament reconstruction. The effect of timing of reconstructionand rehabilitation.Am J Sports Med 1991;19:323-326.

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