The usefulness of MRI in evaluating menisci after meniscus repair

MRI Criteria for Healing at 1 Year After Repair of a Traumatic Meniscal Tear

BACKGROUND

Meniscal repair for a traumatic meniscal tear is increasingly used to preserve the meniscus. Interpreting postoperative magnetic resonance imaging (MRI) scans remains challenging, especially in symptomatic patients. There is a lack of reliable MRI criteria to affirm the healed character of a traumatic meniscal injury repair.

PURPOSE

To identify relevant MRI criteria for meniscal healing after meniscal repair.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

We prospectively included all patients with a traumatic meniscal injury who underwent either an isolated meniscal repair or a repair during a concomitant anterior cruciate ligament reconstruction. A standardized preoperative and postoperative clinical evaluation was performed, along with collection of functional scores-Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee, Lysholm Score, and 36-Item Short Form Health Survey. An MRI scan was performed 1 year postoperatively and compared with the preoperative MRI scan. The following MRI aspects were analyzed: variation of morphology and fat-saturated (FS) T2 intensity signal and pre- and postoperative tear diastasis measurement.

RESULTS

Fifty patients (age, mean ± SD, 28.7 ± 8.5 years [range, 16-45 years]) who were 1 year postoperative were included. All patients were considered clinically healed had the same MRI characteristics. A signal change (FS T2) was observed from a high signal intensity fluid to a nonfluid moderate signal intensity. The morphology of the lesion was more complex: from the initial lesion, line ramifications appeared, creating the appearance of tree branches. The tear diastasis decreased (from 2.3 ± 0.5 mm [range, 1.3-3.5] to 1.1 ± 0.28 mm [range, 0.5-1.5]).

CONCLUSION

MRI criteria confirming meniscal healing after traumatic meniscal repair at 1 year were identified: a change in the intrameniscal signal becoming nonfluid and moderate in intensity; a reduction in tear diastasis to <1.5 mm; and a change in the signal morphology of the repaired meniscus.

3D-MRI combined with signal-to-noise ratio measurement can improve the diagnostic accuracy and sensitivity in evaluating meniscal healing status after meniscal repair

PURPOSE

This study compared the diagnostic accuracy of second-look arthroscopy, clinical assessment, and magnetic resonance imaging (MRI) in evaluating meniscal healing following repair. To explore the application of 3D-MRI sequences with signal-to-noise ratio (SNR) measurements and the analysis of sensitivity and accuracy in evaluating meniscal healing status after meniscal repair.

METHODS

This study included 75 patients (75 menisci; mean age, 25.4 ± 6.6 years) who underwent arthroscopic meniscal repair (medial menisci, 45; and lateral menisci, 29). Follow-up evaluation included clinical assessment, magnetic resonance imaging (MRI), and second-look arthroscopy (mean follow-up, 10.2 ± 3.4 months). The criteria defined for unhealed menisci were: on arthroscopy, presence of cleft; on clinical assessment, presence of joint-line tenderness, swelling, locking, or positive McMurray test; on MRI, grade III signal intensity at the site of repair. Finally, the SNR on 3D-MRI of the healed and the unhealed groups were compared.

RESULTS

On second-look arthroscopy, 68 (90.7%) menisci were found to be completely healed. With the arthroscopic healing rate as the standard, the clinical healing rate was 69.3% (63 menisci) [sensitivity, 85.7%; specificity, 75.0%; accuracy, 76.0%; positive predictive value (PPV), 26.1%; negative predictive value (NPV), 98.1%]. Similarly, the sensitivity, specificity, accuracy, PPV and NPV, respectively, for MRI in four sequences were as follows: 2D-T2W-Sag: 71.4, 79.4, 78.7, 26.3, and 96.4%; 2D-T2W-Cor: 71.4, 82.4, 81.3, 29.4, and 96.6%; 3D-PDW-Sag: 100.0, 50.0, 54.7, 17.1, and 100.0%; 3D-PDW-Cor: 100.0, 58.8, 62.7, 20.0, and 100.0%. The mean SNRs of the healed group (3D-PDW-Sag, 66.7 ± 11.9; 3D-PDW-Cor, 63.9 ± 12.4) were significantly lesser than that of the unhealed group (3D-PDW-Sag, 89.2 ± 9.6; 3D-PDW-Cor, 82.2 ± 18.5) (P < 0.05). Identifying grade 3 meniscal damage on 3D-PDW images prior to applying the different SNR cut-off points revealed SNR values 80 in the sagittal plane and 70 in the coronal plane as having better diagnostic accuracy and sensitivity. The clinical relevance of the study was that 3D-MRI combined with SNR measurement may be a noninvasive and accurate method of assessment clinically, and a reliable alternative to second-look arthroscopy.

LEVEL OF EVIDENCE

III.

MENISCAL REPAIR RESULTS COMPARING MRI, ARTHRO-MRI, AND ARTHRO-CT

Objective

To clinically and radiologically evaluate patients who received meniscal suture using the outside-in technique, comparing magnetic resonance imaging (MRI), arthro-magnetic resonance imaging (arthro-MRI), and arthro-computed tomography (arthro-CT) to evaluate the healing of meniscal sutures.

Methods

We evaluated eight patients with an average follow-up of 15 months. The evaluation analyzed clinical parameters using the Lysholm and IKDC scores as well as MRI, arthro-MRI, and arthro-CT imaging.

Results

At the end of the follow-up period, mean Lysholm score was 89.5 and mean IKDC score was 78.6. In the MRI, signs of meniscal healing were observed in 50% of the cases. The arthro-MRI and arthro-CT showed signs of healing in 75% of cases. There was a positive correlation between arthro-MRI and arthro-CT results in all the cases studied (kappa correlation index=1).

Conclusion

Meniscal suture using the outside-in technique presented good or excellent results in 87.5% of our patients. The arthro-CT and arthro-MRI showed the same level of accuracy in detecting healing of the sutured region of the meniscus. Level of Evidence IV; Case series.

A Current Review of the Meniscus Imaging: Proposition of a Useful Tool for Its Radiologic Analysis

The main objective of this review was to present a synthesis of the current literature in order to provide a useful tool to clinician in radiologic analysis of the meniscus. All anatomical descriptions were clearly illustrated by MRI, arthroscopy, and/or drawings. The value of standard radiography is extremely limited for the assessment of meniscal injuries but may be indicated to obtain a differential diagnosis such as osteoarthritis. Ultrasound is rarely used as a diagnostic tool for meniscal pathologies and its accuracy is operator-dependent. CT arthrography with multiplanar reconstructions can detect meniscus tears that are not visible on MRI. This technique is also useful in case of MRI contraindications, in postoperative assessment of meniscal sutures and the condition of cartilage covering the articular surfaces. MRI is the most accurate and less invasive method for diagnosing meniscal lesions. MRI allows confirming and characterizing the meniscal lesion, the type, the extension, its association with a cyst, the meniscal extrusion, and assessing cartilage and subchondral bone. New 3D-MRI in three dimensions with isotropic resolution allows the creation of multiplanar reformatted images to obtain from an acquisition in one sectional plane reconstructions in other spatial planes. 3D MRI should further improve the diagnosis of meniscal tears.

MR imaging of the postoperative knee

Advances in orthopedic and arthroscopic surgical procedures of the knee such as, knee replacement, ligamentous reconstruction as well as articular cartilage and meniscus repair techniques have resulted in a significant increase in the number of patients undergoing knee arthroscopy or open surgery. As a consequence postoperative MR imaging examinations increase. Comprehensive knowledge of the normal postoperative MR imaging appearances and abnormal findings in the knee associated with failure or complications of common orthopedic and arthroscopic surgical procedures currently undertaken is crucial. This article reviews the various normal and pathological postoperative MR imaging findings following anterior and posterior cruciate ligament, medial collateral ligament and posterolateral corner reconstruction, meniscus and articular cartilage surgery as well as total knee arthroplasty with emphasis on those surgical procedures which general radiologists will likely be faced in their daily clinical routine.

Clinical and radiological results 21 years following successful, isolated, open meniscal repair in stable knee joints

The long-term results over 20 years following meniscal repair in stable knees have not been described yet. The objective was therefore to analyze the clinical and radiological outcomes of successful, isolated, open meniscal repairs with an intact ACL after a mean follow-up of 20.6 years (range, 16-25) retrospectively in 26 patients. Clinical evaluation included objective (Lysholm, IKDC, Tegner) and subjective scores. Standard radiological assessment according to Ahlbäck's osteoarthritis classification and weight-bearing full-leg radiography for alignment were performed. Eight patients were excluded due to a re-rupture of the meniscus. In the 18 remaining patients (12 male, 6 female), the mean Lysholm and IKDC score was 97.8 points (range, 85-100) and 93% (range, 77-100) at the most recent follow-up, respectively. The Tegner activity scale averaged 4.2 (range, 3-7). Subjectively, 13 patients rated their outcome excellent, 4 good, and 1 fair. The radiological evaluation demonstrated an average development of "+1" grade (range, 0-"+2") osteoarthritic changes versus preoperatively; however, the contralateral healthy knee also revealed comparable (on average "+1" grade) degenerative changes reflecting natural history. The alignment was not significantly different between the operated and the contralateral leg. Overall, isolated open meniscal repair in stableness has the potential of a successful surgery with good to excellent long-term results. The development of osteoarthritic changes within the femorotibial compartments is mild and comparable to contralateral and the alignment of the axis is preserved. Therefore, repair of a ruptured meniscus is recommended whenever possible, even in isolated meniscal tears. However, a re-rupture rate of approximately 30% in isolated meniscal tears has to be acknowledged, which still reflects the need for biological enhancement of meniscal healing.

MRI signal changes in completely healed meniscus confirmed by second-look arthroscopy after meniscal repair with bioabsorbable arrows

This study evaluated the MRI signal characteristics and MRI diagnostic accuracy in identifying completely healed menisci repaired with bioabsorbable arrows. A total of 34 patients (38 menisci), with a mean age of 26.0 years, underwent arthroscopic meniscal repair with bioabsorbable arrows and concomitant anterior cruciate ligament (ACL) reconstruction. Of the 34 patients, 27 were male and 7 were female. Of the 38 menisci, 27 were medial and 11 were lateral. Second-look arthroscopy was performed for each patient while taking out the hardware for ACL reconstruction of the tibial side to evaluate the healing status of the repaired menisci. Postoperative MRI was done 2 days before or after second-look arthroscopy. Sagittal T1, T2 and PD images and coronal T2 and PD images were used as the main diagnostic serials. Second-look arthroscopy showed that surfaces of the repaired sites of all 38 menici were almost smooth. In all 38 cases the tail ends of meniscus arrows disappeared and in four patients new overlying injury of compartmental cartilage at the repaired side was detected. MRI results revealed that different serials had different diagnostic accuracy. Sagittal: T1 28.9%, PD 34.2%, T2 60.5%. Coronal: PD 36.8%, T2 65.8%. The double sides Grade 3 signal had a higher proportion in saggital T1 and PD serials, 47.4 and 39.5%, respectively, while lower in sagittal and coronal T2 serials, both 5.3%. MRI diagnostic accuracy was correlated positively with the follow-up time (P < 0.05). MRI has its limitation in evaluating the status of menisci repaired with bioabsorbable arrows, especially for PD and T1 serials. T2 serials have higher diagnostic accuracy than other serials. MRI diagnostic accuracy can be improved by prolonging follow-up time and might be improved by further classifying Grade 3 signal in terms of signal intensity and the shape of the signal margin.

Magnetic resonance imaging of the postoperative meniscus

Imaging of the postoperative meniscus is a challenge. Nevertheless, magnetic resonance imaging (MRI) of the symptomatic knee after meniscal surgery is a valuable diagnostic study of both the menisci and the entire joint. At present, symptomatic patients who have had partial meniscectomy of less than 25% may be evaluated by MRI. For those with partial meniscectomy of greater than 25% or after meniscal repair, direct or indirect magnetic resonance arthrography (MRA) should be considered. Currently, the decision of whether to perform direct (intra-articular) versus indirect (intravenous) MRA must be reviewed on a case-by-case basis considering both the patient's ability to tolerate intra-articular injection and whether a significant effusion already exists, which will imbue the tear with synovial fluid (making intra-articular injection of less importance). In such cases of significant effusion, indirect MRA would be preferred. If MRI or MRA is contraindicated, computed tomography arthrography seems a promising alternative. For a patient who has undergone meniscal allograft transplantation, MRI seems adequate for detecting meniscocapsular healing, allograft extrusion, and allograft tear. Future improvements in MRI sequencing may obviate the need for invasive modalities.

Lateral meniscus repair in a professional ice hockey goaltender: a case report with a 5-year follow-up

STUDY DESIGN

Case report of a professional ice hockey goaltender who underwent an arthroscopically assisted lateral meniscus repair.

BACKGROUND

Rehabilitation of isolated meniscal repairs is not well documented in the literature. There is little knowledge about the healing time and the choice of rehabilitation exercises to be applied to a repaired meniscus. The objective of this case report is to describe a criterion-based, supervised, sport-specific rehabilitation protocol for a high-level athlete with a lateral meniscus repair from the first postoperative day until return to competitive sport, including a 5-year follow-up.

CASE DESCRIPTION

The criterion-based protocol used with this athlete was based on a sport-specific neuromuscular rehabilitation approach. Data collected included range of motion, strength, neuromuscular control, and magnetic resonance images.

OUTCOMES

This high-level athlete was able to return to sport 103 days after surgery and no reinjury of the lateral meniscus occurred up to 5 years after surgery.

DISCUSSION

The sport-specific, criterion-based, supervised rehabilitation program described in this case report showed a safe return to sport and a good long-term outcome.

[MRI after meniscus and cruciate ligament surgery]

Nowadays, due to its high diagnostic accuracy, MR imaging is the method of choice for the evaluation of knee joint disorders pre- and postoperatively. Accurate diagnosis is sometimes possible only if the reporting radiologist has knowledge of the therapeutic procedures and the surgical report. Frequently, further therapeutic management is strongly influenced by MR examinations and radiological reports.

MR imaging evaluation of the postoperative knee: ligaments, menisci, and articular cartilage

The surgical management of knee injuries has increased in recent years. Postoperative magnetic resonance (MR) imaging of the knee following surgical intervention serves an important role in the diagnostic evaluation of patients with recurrent or residual symptoms following surgical intervention. MR imaging additionally assists in the noninvasive documentation of temporal changes at the surgical site potentially reflective of procedural success, or failure. Background understanding of the common surgical procedures performed, their normal postoperative MR imaging appearance, and imaging features of potential procedural complications are essential in the accurate evaluation of patients following prior knee surgery. The focus of the following article is to review the clinical and MR imaging features of the postoperative knee following prior surgical treatment of ligamentous, meniscal, and articular cartilage injuries of the joint.

MR Arthrography of the Knee: How, Why, When

MR arthrography combines the techniques of arthrography with MR imaging to benefit from the added imaging information afforded by intra-articular distention. This article reviews technical considerations for MR arthrography, potential complications, indications, pitfalls in imaging diagnosis, and commonly encountered pathology. It is an elegant study that can offer precise diagnostic information in the appropriate clinical setting.

Imaging the post-operative meniscus

Considerable developments have occurred in meniscal surgery, and consequently in the imaging of post-operative menisci, over the last 15 years. A drive to preserve meniscal physiologic function for as long as possible, in order to delay osteoarthrosis, has resulted in limited partial meniscectomies, meniscal repairs and meniscal transplants. Each of these techniques affects the imaging appearance of the meniscus, reducing the accuracy of conventional MRI in predicting recurrent tears. The specificity of conventional MRI can be improved by employing at least two T2-weighted sequences, but this still leaves a shortfall in sensitivity. In an attempt to increase the diagnostic accuracy of cross-sectional imaging, MR arthrography (MRA) and CT arthrography (CTA), have been applied to the post-operative meniscus. Sensitivities and specificities for these two techniques approach 90% in predicting recurrent meniscal tears. In the setting of clinical symptoms and gross meniscal deficiency, meniscal allografts are being transplanted with increasing frequency. In these transplants meniscal degeneration, fragmentation and separation are common findings, but the role of imaging in the management of these patients has not yet been well defined. This review explores the imaging techniques available for the evaluation of the post-operative meniscus, their strengths and weaknesses, and the reasons that they may find a place in a rational strategy for imaging of the symptomatic post-operative knee.

Eight- to 14-year followup of arthroscopic meniscal repair

The current study aims to elucidate the midterm to long-term progression of arthroscopic meniscal repair which had been confirmed through a second-look arthroscopy at an average of 10 months after repair. Twenty-eight menisci of 28 patients were investigated at 8 to 14 years (mean, 10.2 +/- 1.8 years), eight after isolated meniscal repair (Isolated group) and 20 after concomitant anterior cruciate reconstruction (Anterior cruciate ligament group). All were rated excellent except four that rated good in the anterior cruciate ligament group as indicated by Lysholm's score at followup. None of the Isolated group, but 12 of the Anterior cruciate ligament group, had osteoarthritic changes seen on radiographs. Four and 19, respectively, had increased signal intensity on magnetic resonance imaging scans, 10 in the Anterior cruciate ligament group had changes of Grade 3 severity. However, no meniscal signs or symptoms were present and no significant relationship between findings of radiographs and magnetic resonance imaging scans was apparent. Anterior cruciate reconstructed knees that were changed to Grade 3 severity as seen on magnetic resonance imaging scans had higher sagittal instability seen on stress radiography than knees with Grade 2 or less severe changes. The anterior laxity of the knees influenced the severity of meniscal signal changes on the magnetic resonance imaging scans.

Results of repeat meniscal repair

BACKGROUND

The efficacy of repeat repair of retorn menisci has not been demonstrated.

PURPOSE

To document clinical and radiographic results of repeat repair of retorn menisci that had previously undergone primary repair.

STUDY DESIGN

Uncontrolled retrospective review.

METHODS

Eighteen consecutive repeat meniscal repairs were performed over an 11-year period.

RESULTS

Fourteen of 18 patients (13 repeat meniscal repairs and 1 second repeat meniscal repair) had clinically intact menisci and were available for a mean follow-up of 7.33 years (range, 3.25 to 13.75). The average durability of the initial repair was 3.46 years (range, 0.17 to 14.67). Five patients sustained a tear at the site of rerepair; one underwent second repeat repair of the meniscus and the other four patients underwent partial meniscectomy. The mean Lysholm score for the remaining 14 patients was 82.1 (range, 38 to 100), and the mean Tegner score was 5.6 (range, 2 to 8). On the International Knee Documentation Committee rating scale, five knees received an overall rating of normal; six, nearly normal; and three, abnormal. Radiographs revealed grade 0 changes (normal) in five of the involved knee compartments and grade I changes (sclerosis or mild narrowing measuring 1 to 2 mm) in the remaining five.

CONCLUSIONS

Repeat repair of retorn menisci had a 72% survival rate with relief of symptoms and return to high levels of function.

Long-term assessment of arthroscopic meniscus repair: a 13-year follow-up study

A prospective study was set up to evaluate meniscal suturing using an inside-out technique. Of an initial group of 20 patients who underwent closed meniscus repair between 1985 and 1988 using an inside-out technique, 13 were studied. All patients were subjected to a clinical examination and a magnetic resonance imaging (MRI) investigation. The findings were compared with those of their previous follow-up examination (1994). The Hospital for Special Surgery (HSS) knee rating system (R.G. Stone et al. Athroscopy 1990; 73-78) was used. The study included seven men and six women, ranging in age from 29 years to 50 years (mean age: 35 years 6 months). The mean follow-up was 13 years 2 months (11 years 11 months-15 years 4 months). Six left and seven right knees were involved. Seven patients also had an anterior cruciate ligament (ACL) injury of which one was repaired 6 years after meniscal repair. All patients obtained an HSS score of more than 75%. In all patients, the site of the previous suture was still visible on MRI mainly by small metal artefacts in the meniscus. Patients with an unrepaired ACL lesion had an early onset of arthrosis and cartilage degeneration. Meniscal suturing gives good clinical long-term results. Magnetic resonance imaging, however, showed signs of mucoid degeneration or scar tissue in 46% of the patients.

Magnetic resonance imaging of the knee

Magnetic resonance imaging (MRI) has revolutionised diagnostic imaging of the knee. It has evolved significantly since Kean described healthy and pathologic knee anatomy in 1983. This innovative technology allows superior soft-tissue detail with multiplanar imaging capability that provides accurate evaluation of intra- and extra-articular structures of the knee not demonstrated with other imaging modalities. The development and advancements in MRI and the introduction of high-resolution coils have provided a noninvasive, nonoperator dependent, cost effective means to diagnose knee pathology. MRI is well tolerated by patients, widely accepted by evaluating physicians, and assists in distinguishing pathologic knee conditions that may have similar clinical signs and symptoms (i.e. meniscal tears, osteochondral lesions). This paper presents an overview of MRI of the knee and focuses on the MRI findings in a number of common pathologic conditions.

Histologic change of the meniscus and cartilage tissue after meniscal suture

The influence of suturing on cell infiltration into the meniscus and surrounding tissue is not well known. Histologic changes in the meniscus after suturing and prediction of histologic changes using magnetic resonance imaging were studied. Forty knees in 20 mongrel dogs were studied using four types of 4-0 suture material: nonabsorbable monofilament, nonabsorbable braided, absorbable monofilament, and absorbable braided. Each type of suture material was used for meniscal suture on eight knees each. The other eight knees were not subjected to meniscal suture. Specimens obtained at 1 and 3 months were studied by magnetic resonance imaging and light microscopic analysis. The maximum width of change of meniscal tissue was measured. Changes from the nonabsorbable suture group were smaller than that of the absorbable suture group in magnetic resonance imaging. Histologic changes as seen by light microscope were larger in the absorbable group than in the nonabsorbable group at 1 and 3 months after surgery. Injury was found in the articular cartilage of the femoral condyle in the nonabsorbable braided suture group. Histologic changes were significantly greater when changes in magnetic resonance imaging signal intensity were larger. The current study showed that non-absorbable monofilament suture material results in the least damage to the meniscus and surrounding tissue.

Meniscal allografts: evaluation with magnetic resonance imaging and correlation with arthroscopy

PURPOSE

To correlate clinical results to magnetic resonance imaging (MRI) and arthroscopy after cryopreserved nontissue-antigen-matched meniscal transplantations.

TYPE OF STUDY

Blinded; the observers were blinded for each others' assessment.

MATERIALS AND METHODS

Sixteen consecutive patients were included in the protocol. First, clinical evaluation and MRI were performed. Second, within 24 hours, arthroscopy was performed.

RESULTS

The clinical results showed better correlation between clinical results and arthroscopy than between clinical results and MRI. In the present study, MRI was not beneficial in evaluating meniscal transplants.

CONCLUSIONS

Using more sophisticated MRI techniques, the correlation between clinical results, arthroscopy, and MRI could probably be improved.

Options in meniscal repair

Meniscal repair is an important technique for the orthopaedic surgeon. As familiarity, equipment, and techniques improve, the interest in expanding the indications for application of meniscal repair also increases toward improving patient outcomes and long-term function. An overview of the indications, techniques, complications, and future direction of meniscal repair is presented in this article.

Intermediate-term results of meniscal repair in anterior cruciate ligament-reconstructed knees

We investigated the incidence of and risk factors for recurrent tears of repaired menisci in anterior cruciate ligament-reconstructed knees. We observed 63 patients whose menisci had been evaluated at second-look arthroscopy as healed (N = 50) or incompletely healed (N = 13) for an average of 4 years (range, 2 to 9.5). Of the 13 patients with incompletely healed menisci, 6 (46%) required additional meniscal surgery and 2 (15%) had recurrence of meniscal symptoms such as catching or locking. Among the 50 patients with healed menisci, 5 (10%) required additional meniscal surgery and 9 (18%) had recurrence of meniscal symptoms after second-look arthroscopy. The timing of the recurrence of these symptoms was from 12 to 28 months after surgical repair. Of the 11 patients who had undergone additional surgery, 6 had sustained second injuries during sports activities and the other 5 had no identifiable cause of injury. When comparing age, tear sites, rim width, side-to-side differences with KT-1000 arthrometer testing, and the pivot shift test, there were no differences between the group requiring additional surgery, the symptomatic group, and the asymptomatic group. However, the postoperative Tegner activity score of the group requiring additional surgery was statistically significantly higher than the others.

Knee arthrography. Evolution and current status

This article explores arthrography of the knee beginning with a brief historical perspective of conventional knee arthrography and culminating in direct and indirect MR arthrography of the knee. This article discusses the advantages of MR arthrography in the radiologic assessment of the postoperative meniscus, abnormalities of articular cartilage, and synovial-based processes.

Meniscal repair in the goat model. The use of healing adjuncts on central tears and the role of magnetic resonance arthrography in repair evaluation

We evaluated the effect of adjunctive healing measures on central tears of the adult goat medial meniscus and the role of magnetic resonance arthrography in the assessment of menisci that have undergone a repair. Peripheral tears were made unilaterally in the medial menisci of seven goats in Group I and repaired with nonabsorbable suture. Six Group II goats had central medial meniscal tears repaired as in Group I plus an exogenous fibrin clot. Eight Group III goats had central tears plus abrasion of the parameniscal synovium and tear edges. Six months after surgery, a magnetic resonance imaging scan and a magnetic resonance arthrogram were obtained and the menisci were examined grossly. Group I goats showed healing in all seven knees. Central tears repaired with a fibrin clot (Group II) showed healing in one of six knees (17%). Central tears repaired with abrasion (Group III) showed healing in seven of eight knees (87.5%). Magnetic resonance arthrography was 100% accurate in detecting the presence or absence of complete residual tears. This study supports the current trend of using adjunctive measures for repair of central tears. Furthermore, abrasion of the parameniscal synovium and the tear edges appears to be more effective than the use of an exogenous fibrin clot. Magnetic resonance arthrography is useful in the evaluation of menisci that have undergone repair.

Arthroscopic repair of meniscal tears that extend into the avascular zone. A review of 198 single and complex tears

We assessed the results of 198 meniscal tears that had a major segment in the central avascular region repaired with an arthroscopically assisted inside-out technique. There were 177 patients whose mean age was 28 years. Eighty-two percent were injured during sports, and 71% also required anterior cruciate ligament reconstruction. The menisci were evaluated by clinical examination (180 repairs) a mean of 42 months postoperatively, by follow-up arthroscopic evaluation (91 repairs) a mean of 18 months postoperatively, or both. At followup, 159 (80%) of the 198 tears were asymptomatic for tibiofemoral joint symptoms, and 39 (20%) required repeat arthroscopic surgery for these symptoms. Of the 91 repairs evaluated arthroscopically, 23 (25%) were classified as healed, 35 (38%) as partially healed, and 33 (36%) as failed. We recommend repair of meniscal tears that extend into the avascular region for select patients, including those in their 20s and 30s and highly competitive athletes. This study's reoperation rate of 20% should not be interpreted as the rate of meniscal healing, but as the incidence of tibiofemoral joint symptoms. Even though this is a higher rate than that reported for the repair of peripheral meniscal tears, we believe the benefits of a potentially functional meniscus outweigh the risks of reoperation.

Arthroscopic medial meniscal repair in the athlete

Meniscal tears are common sports injuries. This article details the clinical evaluation of the athlete presenting with knee pain. Conservative (nonoperative) treatment and arthroscopic procedures are discussed.

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

Twenty-two patients who underwent meniscal repair using the outside-in 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 degrees 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.

MRI of anterior cruciate ligament healing

OBJECTIVE

The purpose of this study was to evaluate using MRI the natural healing of the anterior cruciate ligament (ACL) when treated conservatively by early protective motion.

MATERIALS AND METHODS

Consecutive acute complete intraligamentous ruptures of the ACL in 50 cases that were allowed to heal without surgery were evaluated before and after 3 month treatment by MRI, arthroscopy, and stress radiographs. Twenty-nine of the 50 patients were also reevaluated 11 months from the initial injury, of which 7 were reevaluated again 24 months from the initial injury by MRI. The MR appearance of the treated ACL was categorized into four grades depending on homogeneity, straight band, and size.

RESULTS

MR assessment of the ACL after 3 month treatment demonstrated a well defined normal-sized straight band in 37 cases (74%). There was a significant relationship between the 3 and 11 month MR evaluations (rs = 0.801, p <0.0001). There were also significant relationships between the MR and arthroscopic evaluations (rs = 0.455, p <0.005) and between the MR stress radiographic evaluations (rs = 0.348, p <0.025) after the 3 month treatment.

CONCLUSION

MRI can demonstrate ACL healing when treated conservatively with early protective mobilization.

Magnetic resonance signals in healing menisci: an experimental study in dogs

This study examined the magnetic resonance imaging (MRI) signal from healing menisci in adult dogs. Complete, full-thickness radial tears were created in the medial menisci of adult dogs and allowed to heal spontaneously. Menisci were harvested and examined at 8, 12, and 26 weeks after injury using a spin-echo imaging sequence. After imaging, the menisci were processed for routine histologic examination. The results of the study demonstrated that the repair tissue consistently yielded an increased MRI signal as compared with the normal meniscal tissue. This increased signal persisted at 26 weeks even though the repair tissue had modulated from fibrovascular scar tissue into fibrocartilage. The results of this study confirm the clinical impression that normal fibrovascular repair tissue in the healing meniscus can emit persistently increased signals on MRI examination. However, the long-term history of these signals remains unknown.