Evaluation of meniscal repair with serial magnetic resonance imaging: a comparative study between conventional MRI and indirect MR arthrography

Radial and longitudinal meniscus tears show different gapping patterns under stance phase conditions

Meniscal tearing can increase the contact pressure between the tibia and femur by causing gapping of torn meniscus tissue. The aim of this study was to quantify gapping behavior of radial and longitudinal tears and their impact on peak contact pressure and mean contact area. Twelve porcine knee joints underwent unicondylar, convertible osteotomy for exact tear application and consecutive suturing. Six tantalum marker beads were positioned along meniscus tears. The joints were preloaded with sinusoidal loading cycles ranging between 0 N and 350 N. Peak load was held constant and two synchronized Roentgen stereophotogrammetric analysis x-ray images were obtained to evaluate gapping, peak contact pressure and mean contact area in the native, torn and repaired states. There was no change in gapping or peak contact pressure in longitudinal tear. By contrast, the radial tear led to a significant gapping when compared to the native state, while the inside-out suture was able to restore gapping in parts of the meniscus. An increase in contact pressure after radial tear was detected, which was again normalized after suturing. The most important finding of the study is that longitudinal tears did not gap under pure axial loading, whereas radial tears tended to separate the tear interfaces.

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.

In-Office Needle Arthroscopy Can Evaluate Meniscus Tear Repair Healing as an Alternative to Magnetic Resonance Imaging

PURPOSE

To assess the healing of horizontal cleavage tears of the meniscus 1 year after surgical repair and to determine what modality is best to determine healing.

METHODS

Patients were prospectively followed for 12 months after surgical meniscus repair using a circumferential compression stitch. Inclusion criteria were preoperative magnetic resonance imaging (MRI) evidence of horizontal cleavage tear, age between 18 and 50 years, and no concomitant anterior cruciate ligament reconstruction. Patients were excluded if they were >50 years old, had a meniscus tear pattern other than horizontal cleavage tear, and underwent concomitant ligament reconstruction. MRIs were performed 1-year postoperatively for evaluation of repair healing. Preoperative and postoperative MRIs of tears were evaluated blindly by a musculoskeletal radiologist. In-office needle arthroscopy was performed at 6 months post-operatively.

RESULTS

Eight patients were included and had surgery between March 2016 and November 2017. There were 4 medial and 4 lateral meniscus tears. No patients had recurrence of preoperative symptoms or evidence of retear. Six repairs evaluated by in-office needle (at 5.9 months postsurgery) arthroscopy demonstrated complete healing. Seven of the 8 patients had grade III changes on preoperative MRI, and 1 patient had grade IIc changes. On postoperative MRI, 5 of 7 patients had grade III changes, 1 patient had IIc changes, and 1 had IIb changes. There was no significant difference in the proportion of patients with grade III changes preoperatively compared with postoperatively (P = .57). One of 8 patients with preoperative MRIs demonstrated extrusion where no patients demonstrate postoperative MRI evidence of extrusion (P = .47).

CONCLUSIONS

Horizontal cleavage meniscal tears repaired with a circumferential compression stitch demonstrate healing on in-office needle arthroscopy 6 months after surgery. No evidence of incomplete or failed healing was found. MRI at 1 year after surgery demonstrated residual tear evidence for all patients.

LEVEL OF EVIDENCE

IV, therapeutic case series.

Evaluation of Meniscal Tissue after Meniscal Repair Using Ultrahigh Field MRI

The study evaluates the meniscal tissue after primary meniscal suturing using 7-Tesla (T) magnetic resonance imaging with T₂* mapping at 6 and 12 months after surgery to investigate the differences between repaired meniscal tissue and healthy meniscal tissue in the medial and lateral compartment. This prospective study included 11 patients (9m/2f) with a mean age of 30.6 years (standard deviation 9.0). Patients with a meniscal tear that was treated arthroscopically with meniscus suturing, using an all-inside technique, were included. All patients and seven healthy volunteers were imaged on a 7-T whole-body system. T2* mapping of the meniscus was applied on sagittal slices. Regions-of-interest were defined manually in the red and white zone of each medial and lateral meniscus to measure T2*-values. In the medial posterior and medial anterior horn similar T₂*-values were measured in the red and white zone at 6- and 12-month follow-up. Compared with the control group higher T₂*-values were found in the repaired medial meniscus. After 12-months T₂*-values decreased to normal values in the anterior horn and remained elevated in the posterior horn. In the red zone of the lateral posterior horn a significant decrease in the T₂*-values (from 8.2 milliseconds to 5.9 milliseconds) (p = 0.04), indicates successful repair; a tendency toward a decrease in the white zone between the 6 and 12 months follow-up was observed. In the red zone of the lateral anterior horn the T₂*-values decreased significantly during follow-up and in the white zone of the lateral anterior horn T₂*-values were comparable. In comparison to the control group higher T₂*-values were measured at 6-months; however, the T₂*-values showed comparable values in the repaired lateral meniscus after 12 months. The T2* mapping results of the current study indicated a better healing response of the red zone of the lateral posterior horn compared with the medial posterior horn.

Clinical Outcomes of Inside-Out Meniscal Repair According to Anatomic Zone of the Meniscal Tear

Background

There is significant discrepancy in the reported vascularity within the meniscus, and a progressively diminishing blood supply may indicate a differential healing capacity of tears that is dependent on the affected meniscal zone.

Purpose

To examine the outcomes after inside-out meniscal repair in all 3 meniscal vascularity zones.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients were included if they underwent inside-out meniscal repair by a single surgeon between 2010 and 2014 and had a minimum 2-year follow-up. Patients were divided into 3 groups based on the meniscal tear location (red-red, red-white, and white-white zones) as determined during an intraoperative assessment. Patient-reported outcome scores were obtained at final follow-up.

Results

A total of 173 patients (mean age, 33.6 ± 14.3 years) were included, with a mean follow-up of 2.9 ± 0.9 years. All patients demonstrated significant improvements with inside-out meniscal repair from preoperatively to postoperatively, regardless of the meniscal tear location. Patients who underwent meniscal repair in the red-red and red-white zones had significantly increased postoperative Tegner, Lysholm, and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores compared with patients who underwent meniscal repair in the white-white zone (P < .05). Patients who underwent acute repair (≤6 weeks) demonstrated significantly higher improvements on the Tegner activity scale (acute: 5.8 ± 2.2; chronic: 4.6 ± 2.2; P = .001) and Lysholm score (acute: 85.6 ± 13.3; chronic: 80.8 ± 13.5; P = .025) compared with patients treated beyond 6 weeks from injury, regardless of the meniscal tear zone. Patients with grade IV femoral condyle chondral lesions at the time of surgery had significantly inferior outcomes compared with patients with grade I through III chondral lesions, regardless of the meniscal tear zone. Three patients (1.7%) subsequently underwent revision inside-out repair, and 3 (1.7%) underwent partial meniscectomy.

Conclusion

Patients who underwent inside-out meniscal repair demonstrated significant improvements on subjective outcome measures at a minimum 2-year follow-up, regardless of the meniscal tear zone. Inside-out meniscal repair is recommended for potentially reparable meniscal tears in all 3 vascular zones; however, improved outcomes can be achieved when performed acutely, in the absence of full-thickness femoral condyle chondral injuries, and in the red-red and red-white zones.

[Clinical efficacy of arthroscopic simultaneous treatment for anterior cruciate ligament injury combined with meniscus bucket-handle tear]

Objective

To explore the clinical efficacy of arthroscopic simultaneous both anterior cruciate ligament (ACL) reconstruction and suture of the meniscus bucket-handle tear (BHT).

Methods

Between January 2013 and April 2014, 22 patients (22 knees) with ACL injury and BHT, who accorded with the inclusion criteria, were studied. There were 14 males and 8 females with a mean age of 30.68 years (range, 15-44 years). The left side was involved in 10 cases and the right side in 12 cases. Injury located at the medial meniscus in 14 patients, and at the lateral meniscus in 8 patients. The median of interval from injury to operation was 40 days (range, 9 hours to 4 years). BHT was sutured, and then single bundle reconstruction of ACL was performed under arthroscopy.

Results

All incisions healed by first intention, and there were no serious complications such as infection, vascular injury, and nerve injury. The patients were followed up for 26.7 months on average (range, 12-42 months). At 6 weeks after operation, one patient had limited motion of the knee, the function was recovered after release under anesthesia; and one patient had joint space tenderness, which was relieved after conservative treatment. The total effective rate was 90.9% (20/22). At last follow-up, the anterior drawer test, Lachman test, and McMurray test were negative in all the cases. The visual analogue scale (VAS), Tegner activity level score, and Lysholm score were significantly improved at 12 months after operation when compared with preoperative scores ( P<0.05). At 6-12 months after operation, complete healing was obtained in 7 cases, and partial healing in 11 cases, and nonunion in 4 cases based on MRI evaluation criteria by Crues et al. There was no rupture of reconstruc-tive ligament during follow-up.

Conclusion

Arthroscopic simultaneous both ACL reconstruction and suture of BHT can improve the symptoms, reduce the risk of re-tear of sutured meniscus effectively, delay degeneration of articular cartilage, and maintain the stability of the knee joint.

Complex Meniscus Tears Treated with Collagen Matrix Wrapping and Bone Marrow Blood Injection: A 2-Year Clinical Follow-Up

OBJECTIVE

To collect and analyze the 2-year follow-up clinical and MRI results of patients treated with an arthroscopic technique of collagen membrane-based meniscus repair.

DESIGN

53 consecutive patients with combined (horizontal and radial or longitudinal component) and complex meniscal tears (tear extended through avascular zones or/and composed with two or more morphological tear pattern) were treated with an "all-inside" arthroscopic suture of meniscus and wrapping with a collagen membrane (Chondro-Gide) technique with bone marrow blood injection. The IKDC 2000 subjective score, IKDC 2000 clinical evaluation score, Lysholm score and Barret clinical criteria of meniscal healing were recorded. All patients were examinated by MRI 2 years postoperatively, using modified WORMS criteria for meniscal integrity.

RESULTS

The 2 year follow-up was achieved in 50 cases. Of these, 2 patients were excluded from the evaluation due to incomplete data and 2 patients underwent partial meniscectomy and were classified as failures. In 46 patients (86.8% of the intended to treat cases), a statistically significant improvement in IKDC 2000 subjective, Lysholm scores and IKDC 2000 clinical assessment between preoperative and the 2-year follow-up time points were obsereved. Barret criteria demonstrated an improved clinical outcome between pre- and post-operative values. MRI revealed a non-homogeneous signal without meniscal tear (WORMS grade 1) in 76% of the operated menisci (13% WORMS grade 2).

CONCLUSIONS

The 2-year follow-up data demonstrate that this technique is safe and can offer an additional tool to save the meniscus in the patients otherwise scheduled for meniscal removal. Level of evidence IV.

MR-arthrography assessment after repair of chronic meniscal tears

PURPOSE

The aims of this study were to assess the healing rate of repair of chronically torn meniscal tear with MR-arthrography and to evaluate the relationship between the clinical and the radiographic outcomes and the impact of the meniscal section on healing.

METHODS

MR-arthrography was performed at a median of 10.5 months (range 6-55) after surgery in 28 patients and healing assessed using Henning's criteria. All lesions were chronic (>3 months). Repairs were carried out at a median 14 months (range 6-80) from initial diagnosis. Eleven patients (39%) had ACL ligament reconstruction as well. All lesions were located in the red or red-white zone. Patients were followed for a median of 18.5 months (range 8-68). Functional outcomes were evaluated using Barrett's healing criteria, Lysholm and Tegner score pre- and postoperatively.

RESULTS

Clinical healing of the lesion according to Barrett's criteria was achieved in 24 patients (85.7%). Both Lysholm and Tegner scores improved significantly after the surgery (p < 0.05). According to Henning's criteria, 15 of the menisci healed completely (53.5%), 10 partially (35.7%) and 3 failed (10.8%). There was no significant difference between the healing process in the posterior horn and the body of the meniscus (n.s.). No correlation was found between the healing results and the clinical scores. ACL reconstruction did not influence the healing process (n.s.). Patients waiting more than 1 year from lesion to surgery seem to have a higher rate of failure (p = 0.02).

CONCLUSIONS

The results found suggest good short-term clinical and anatomic outcomes post-repair of meniscal lesions, despite their chronic nature. Longer waiting times may have negative effects on the healing process. Partial healing occurred often, but the meniscus was painless and stable.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

The value of magnetic resonance arthrography in the evaluation of repaired menisci

AIM

To evaluate the diagnostic value of direct magnetic resonance (MR) arthrography in detection of re-torn or unhealed menisci which were previously repaired.

MATERIALS AND METHODS

Twenty-six menisci of 24 symptomatic patients who had undergone a meniscus repair surgery were included in this retrospective study. These patients had been evaluated with gadolinium-enhanced direct MR arthrography. A subsequent second-look arthroscopy was performed thereafter. The findings of MR arthrography were compared with the arthroscopic findings.

RESULTS

Sixteen recurrent meniscal lesions were detected with MR arthrography; the remaining ten repaired menisci were evaluated as healed. At second-look arthroscopy, six out of 26 repaired menisci were evaluated as completely healed. Eight of them had incomplete healing, and 12 of them were unhealed. MR arthrography had four false-negative results, but there were none false-positive results. It was arthroscopically shown that three of these four false-negative results were belonged to patients who had incomplete healing. MR arthrography had a sensitivity, specificity, and overall accuracy of 80, 100, and 84.6 %, respectively. When incomplete lesions were left out of analysis, its sensitivity and accuracy reached to 94.8 and 94.4 %.

CONCLUSION

The findings of this study showed that MR arthrography was a reliable diagnostic tool in evaluating previously repaired menisci. Yet diagnosis of incomplete meniscal lesions seemed to be challenging.

Arthroscopic inside-out repair of complete radial tears of the meniscus with a fibrin clot

PURPOSE

To report on the results of 12 complete radial tears of the meniscus treated using arthroscopic inside-out repair with fibrin clots, the results showed good meniscal healing and excellent clinical outcomes.

METHODS

From 2007 to 2009, 12 patients with complete radial tears of the meniscus were treated by arthroscopic inside-out repair with fibrin clots. In all patients, the International Knee Documentation Committee (IKDC) subjective knee form and Lysholm score were determined pre- and post-operatively. We performed magnetic resonance imaging (MRI) and if indicated, we performed a second-look arthroscopic examination.

RESULTS

At a mean of 30 ± 4 postoperative months, the Lysholm score and IKDC subjective knee score had improved from 65 ± 6 and 57 ± 7 to 94 ± 3 and 92 ± 3, respectively. Eleven of 12 cases showed complete healing on follow-up MRI. Six of 7 patients undergoing a second-look arthroscopic examination had healed completely.

CONCLUSION

This study shows successful meniscal repairs using fibrin clots in complete radial tears. This surgical procedure appears to be a good treatment method for complete radial tear of the meniscus.

LEVEL OF EVIDENCE

Case series, level IV.

Magnetic resonance imaging is not suitable for interpretation of meniscal status ten years after arthroscopic repair

PURPOSE

The purpose of this study was to assess the MRI features of the all-inside repaired meniscus in the long-term.

METHODS

Among 27 consecutive all-inside arthroscopic meniscal repairs, 23 patients aged 25 ± 5 years at the time of surgery were reviewed at a median follow-up of 10 ± 1 years. Retrospective clinical examinations and imaging assessments using a 1.5-T MRI after all-inside arthroscopic meniscal repair were conducted.

RESULTS

At follow-up, Lysholm and IKDC averaged 89 ± 11 and 95 ± 8, respectively. MRI examinations revealed no meniscal signal alteration in three patients (13%), a vertical signal located in the previously torn area in seven (30%), a horizontal grade 3 in nine (39%), and a complex tear (grade 4) in four (17.5%). There were no differences between medial and lateral menisci (p = 0.15), stable and stabilised knees (p = 0.56).

CONCLUSIONS

Several abnormal vertical and/or horizontal hypersignals are still present on MRI examination ten years after arthroscopic all-inside meniscal repair. The appearance of early signs of osteoarthritis is rare, suggesting a chondroprotective effect of the repaired meniscus.

Clinical outcomes of open meniscal repair of horizontal meniscal tears in young patients

PURPOSE

Symptomatic horizontal meniscal tears in young patients are a singular entity. The extent of the lesion is often large, without any injury to the knee. The meniscal tissue might be degenerative. However, a complete resection of the lesion would result in a subtotal meniscectomy. The purpose of this study was to consider the use of a meniscal repair in such patients in order to close the horizontal cleavage extending up to the avascular zone. The hypothesis was that the clinical outcomes after open meniscal repair of horizontal tears are good with a low rate of secondary meniscectomy.

METHODS

Between 1998 and 2006, 28 patients (30 knees) underwent an open meniscal repair to treat symptomatic horizontal meniscal tears [6 women and 22 men, median age 25 years (16-44 years)]. The duration of symptoms was at least 12 weeks (12-72 weeks). Open meniscal repair was performed following arthroscopy. There were 14 medial and 7 lateral menisci, 10 grade 3 tears, and 11 grade 2 tears. If present (15 cases), meniscal cysts were removed using the same approach. Clinical outcomes were evaluated using KOOS and IKDC scores. The return to sporting activities and the need for a secondary meniscectomy were also assessed.

RESULTS

Twenty-one patients were evaluated at a median follow-up of 40 months (24-101 months). Twenty returned to their preinjury level of sporting activity. The median KOOS score was 92 ± 12.9. The median subjective IKDC score was 89 ± 14.1. There were four secondary meniscectomies.

CONCLUSIONS

Open meniscal repair of complex horizontal tears extending into the avascular zone was effective at midterm follow-up in young and active patients. The meniscus was preserved in 80 % of cases. Functional results deteriorated in those older than 30 years. This entity should be differentiated from degenerative meniscal tears that often occur in patients over 50, which may be associated with osteoarthritis.

LEVEL OF EVIDENCE

Retrospective study, Level IV.

Changes in magnetic resonance imaging signal intensity of transplanted meniscus allografts are not associated with clinical outcomes

PURPOSE

To evaluate changes in intrameniscal signal intensity (IMSI) of transplanted allografts during the first year after meniscus allograft transplantation (MAT) by use of serial magnetic resonance imaging, as well as to analyze the relation between IMSI and clinical outcome.

METHODS

This prospective study involved 43 patients who underwent MAT between 2006 and 2007 after diagnosis of total or subtotal meniscectomized knees. The mean patient age at the time of surgery was 35.8 years (range, 17 to 46 years). Allografts were assessed by conventional magnetic resonance imaging performed at 6 weeks and 3, 6, and 12 months after MAT. The ratio of the signal intensity of the transplanted meniscus allograft to that of the control normal meniscus in the ipsilateral knee was calculated to obtain a standardized signal intensity value. IMSI was assessed in terms of postoperative time and location (anterior v posterior horn). The Lysholm score was used to evaluate knee function.

RESULTS

The IMSI of transplanted allograft menisci was higher than that for nontransplanted menisci at all 4 postoperative time points (P < .01). The anterior horn allograft IMSI was greater than the posterior horn allograft IMSI at all time points (P < .01). The allograft IMSI increased starting 3 months postoperatively for the anterior horn (F(3,40) = 7.5, P < .01) and 6 months postoperatively for the posterior horn (F(3,40) = 9.2, P < .01). These increases were maintained to the final assessment at 1 year postoperatively. No correlation was found between IMSI and postoperative Lysholm score.

CONCLUSIONS

Transplanted allograft menisci had higher signal intensities than normal menisci. Signal intensity was higher for the anterior horn than the posterior horn throughout the first postoperative year. Signal intensity increased over time, and this increase was maintained at 1 year postoperatively. However, signal intensity was not related to clinical outcome.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria based on analysis of consecutive patients, applying a universally recognized gold standard.

All-inside meniscal repair with bioabsorbable meniscal screws or with bioabsorbable meniscus arrows: a prospective, randomized clinical study with 2-year results

BACKGROUND

All-inside meniscal repairs have gained popularity in the past few years. However, only a few prospective, randomized clinical studies have been done to compare different all-inside meniscal repair techniques.

HYPOTHESIS

Meniscal repair with bioabsorbable meniscal screws and arrows results in similar clinical outcome on short-term follow-up.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Forty-two patients were prospectively randomized to have all-inside meniscal repair either by using bioabsorbable meniscal screws or bioabsorbable meniscus arrows (21 patients, 23 meniscal repairs in each group) for the fixation. The evaluation methods were clinical examination, Lysholm score, the International Knee Documentation Committee (IKDC) knee score, and magnetic resonance arthrography (MRA) evaluation. The average follow-up time was 27 months (standard deviation, 8).

RESULTS

There were no differences between the study groups preoperatively. All 42 patients (100%) were available for the follow-up. However, during the follow-up, 11 patients had clinical failure, confirmed at second-look arthroscopy, of the repair leading to partial meniscal resection. Four failures (all on the medial meniscus) were observed with the use of meniscal screw fixation (17%), and 7 (4 on the medial meniscus, and 3 on the lateral meniscus) with the use of meniscus arrow fixation (30%) (P = .242). Six patients with meniscus arrows (29%) had chondral damage on the femoral condyles evaluated by MRA or at second-look arthroscopy, while none of the patients with the meniscal screws had the same (P = .018). However, the Lysholm and the IKDC scores were similar in both groups at follow-up.

CONCLUSION

All-inside meniscal repair with bioabsorbable meniscal screws and arrows resulted in similar clinical outcome, although significantly more chondral damage was observed when using bioabsorbable meniscus arrows for fixation.

Cam impingement of the posterior femoral condyle in medial meniscal tears

PURPOSE

The aim of this study was to compare the results of meniscal repair of the medial meniscus with or without decompression of the posterior segment of the medial meniscus for the treatment of posteromedial tibiofemoral incongruence at full flexion (PMTFI), which induces deformation of the posterior segment on sagittal magnetic resonance imaging (MRI).

METHODS

For more than 2 years, we followed up 27 patients with PMTFI who were classified into the following 2 groups. Group 1 included 8 patients (5 male joints and 3 female joints) with a medial meniscal tear with instability at the site of the tear who underwent meniscal repair. The mean age was 23.6 years. Group 2 included 19 patients (16 male joints and 3 female joints) who had a meniscal tear with instability at the site of the tear and underwent meniscal repair and decompression. The mean age was 26.5 years. In decompression of the posterior segment, redundant bone tissue on the most proximal part of the medial femoral condyle was excised. The patients were assessed by use of the Lysholm score, sagittal MRI at full flexion, and arthroscopic examination.

RESULTS

There were no statistical differences in mean Lysholm score between the 2 groups before surgery, but the mean score in group 2 was significantly higher than that in group 1 after surgery. Meniscal deformation of the posterior segment at full flexion on MRI disappeared in all cases after decompression. On second-look arthroscopy, the rate of complete healing at the site of the tear was 0% in group 1 but 57% in group 2, and it was significantly different between these groups.

CONCLUSIONS

The addition of decompression of the posterior segment of the medial meniscus to meniscal repair of knee joints with PMTFI allowed more room for the medial meniscus to accommodate and improved both function of the knee joint and the rate of success of repair of isolated medial meniscal tears in patients who regularly performed full knee flexion.

MRI follow-up of conservatively treated meniscal knee lesions in general practice

Objective

To evaluate meniscal status change on follow-up MRI after 1 year, prognostic factors and association with clinical outcome in patients with conservatively treated knee injury.

Methods

We analysed 403 meniscal horns in 101 conservatively treated patients (59 male; mean age 40 years) in general practice who underwent initial knee MRI within 5 weeks of trauma. We performed ordinal logistic regression analysis to analyse prognostic factors for meniscal change on follow-up MRI after 1 year, and we assessed the association with clinical outcome.

Results

On follow-up MRI 49 meniscal horns had deteriorated and 18 had improved. Age (odds ratio [OR] 1.3/decade), body weight (OR 1.2/10 kg), total anterior cruciate ligament (ACL) rupture on initial MRI (OR 2.4), location in the posterior horn of the medial meniscus (OR 3.0) and an initial meniscal lesion (OR 0.3) were statistically significant predictors of meniscal MRI appearance change after 1 year, which was not associated with clinical outcome.

Conclusion

In conservatively treated patients, meniscal deterioration on follow-up MRI 1 year after trauma is predicted by higher age and body weight, initial total ACL rupture, and location in the medial posterior horn. Change in MRI appearance is not associated with clinical outcome.

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.

Meniscal healing after meniscal repair: a CT arthrography assessment

BACKGROUND

Studies evaluating healing of repaired meniscus are rare and primarily retrospective. The aim of this study was to assess whether there were different healing rates for arthroscopic meniscal repair with respect to the different zones of the meniscus.

PURPOSE

This study was conducted to assess outcomes and to document anatomic characteristics of the repaired meniscus with postoperative arthrography combined with computed tomography (arthro-CT), particularly the dimensions and healing of the repaired meniscus.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Fifty-three arthroscopic meniscal repairs were prospectively evaluated between 2002 and 2004 in 2 orthopaedic departments. There were 36 medial and 17 lateral torn menisci. All ACL tears (n = 31, 58.5%) underwent reconstruction. Patients were preoperatively evaluated by magnetic resonance imaging. Clinical evaluation included International Knee Documentation Committee (IKDC) scores before the operation and 6 and 12 months afterward. Healing criteria were evaluated at 6 months by arthro-CT scan. Three parameters were evaluated--healing in thickness (Henning criteria), overall healing rate, and reduction in the width of the remaining meniscus.

RESULTS

According to the objective IKDC score, 26 patients were graded A, 20 B, and 4 C (92% good results). The mean subjective IKDC score was 78.9 (standard deviation [SD], 16.2). According to Henning's criteria, 58% of the menisci healed completely, 24% partially, and 18% failed. The overall healing rate was 73.1% (SD, 38.5). Twenty tears located in the posterior part had a healing rate of 59.8% (SD, 46.0). Nineteen tears extending from the posterior to the middle part had a healing rate of 79.2% (SD, 28.2). Isolated tears located in the posterior part had a lower healing rate (P < .05). There was a 9% +/- 1.2% reduction in the width of the remaining medial meniscus in the middle and posterior repaired portions (P < .02). There was a 15% +/- 14% reduction in the width of the remaining lateral meniscus in the middle repaired portion (P < .01). Complete healing of the posterior segment was associated with reduction in the width of the meniscus (P < .04).

CONCLUSION

A modern technique using all-inside fixation or outside-in sutures provided good clinical and anatomic outcomes. No statistically significant effect on ACL reconstruction or laterality (medial vs lateral) on overall healing after meniscal repair was identified. Partial healing occurred often, with a stable tear on a narrowed and painless meniscus. The posterior segment healing rate remained low, suggesting a need for further technical improvements.

MR imaging of the meniscus: review, current trends, and clinical implications

MR imaging is the preferred imaging modality for evaluating the meniscus. Overall, when strict criteria are followed, it is accurate in diagnosing meniscal tears in patients who have not had prior meniscal surgery. However, an accurate interpretation requires a through knowledge of the normal meniscal anatomy, common meniscal variants, and common diagnostic pitfalls. In this article, the author emphasizes the importance of describing meniscal tears properly and discusses treatment options. Diagnosing a recurrent tear is more complicated in patients who have had prior partial meniscal resection or repair, and the use of MR arthrography in this group of patients is discussed. Recent developments in areas such as 3 T and parallel imaging offer promise for accurate meniscal evaluation with even shorter scan times.

Follow-up of collagen meniscus implants by MRI

PURPOSE

The purpose of our study was to evaluate the usefulness of magnetic resonance imaging (MRI) in the follow-up of patients treated with collagen meniscus implant (CMI) and to identify MRI patterns suitable for defining its evolution.

MATERIALS AND METHODS

Between March 2001 and June 2003, CMI was performed on 40 patients (27 men and 13 women, age 23-58 years, median 41 years) affected by irreparable medial meniscal lesions. All patients underwent MRI follow-up at 6 months and 1 year and 16 patients 2 years after the operation; 12 patients underwent second-look arthroscopy with implant biopsy. All MRI examinations were performed with a 1.5-T unit using GE T2*, spin-echo (SE) T1, and FatSat fast spin-echo (FSE) DP and T2-weighted sequences, with different orientations. At 24 months, MR arthrography was also performed. Implant evolution was assessed on the basis of MRI direct and indirect criteria. Direct criteria were morphology and signal intensity of the collagen meniscus/residual meniscus complex. Based on these characteristics, three pattern were identified and classified from 1 to 3, where a higher score corresponded to characteristics approaching those of the normal meniscus. Indirect criteria were chondral surface and subchondral bone marrow oedema at implant site and associated synovial pathology.

RESULTS

MRI follow-up at 6 months showed CMI shape and size to be normal (type 3) in 35/40 patients and type 2 in 5/40 patients. CMI signal intensity was type 1 in 32/40 patients and type 2 in 8/40. An interface between prosthetic and native meniscus was identified in 27/40 patients. Chondral lesions were present in 3/40 cases and subchondral bone marrow oedema in 8/40 cases. Reactive synovial effusion was seen in 2/40 patients. MRI follow-up at 12 months showed CMI shape and size to be normal (type 3) in 33/40 patients and type 2 in 7/40. Signal intensity was type 1 in 14/40 patients and type 2 in 26/40 patients. The interface was seen in 19/40 patients. The associated chondral lesions were unchanged, whereas subchondral bone marrow oedema was present in 3/40 patients. No synovial reaction was detected. At 24 months, CMI size was type 3 in 9/16 patients, type 2 in 6/16, and type 1 in one patient in whom the implant could not be identified, as it had been totally resorbed. CMI signal intensity was type 2 in 11/15 and type 3 in 4/16. The interface was identified in seven patients. MR arthrography depicted two additional chondral lesions and enabled correct grading of all lesions. Subchondral bone marrow oedema was present in two patients only.

CONCLUSIONS

MRI enables morphological and structural changes of CMI to be monitored over time. Follow-up can be extended beyond 2 years, until the CMI has stabilised and subchondral bone marrow oedema has completely resolved. In the single case with a poor CMI outcome, no related direct or indirect signs were identified.

MR Imaging of the Meniscus: Review, Current Trends, and Clinical Implications

MR imaging is the preferred imaging modality for evaluating the meniscus. Overall, when strict criteria are followed, it is accurate in diagnosing meniscal tears in patients who have not had prior meniscal surgery. However, an accurate interpretation requires a through knowledge of the normal meniscal anatomy, common meniscal variants, and common diagnostic pitfalls. In this article, the author emphasizes the importance of describing meniscal tears properly and discusses treatment options. Diagnosing a recurrent tear is more complicated in patients who have had prior partial meniscal resection or repair, and the use of MR arthrography in this group of patients is discussed. Recent developments in areas such as 3 T and parallel imaging offer promise for accurate meniscal evaluation with even shorter scan times.

Bucket-handle meniscal lesions: magnetic resonance imaging criteria for reparability

PURPOSE

The purpose of this study was to determine the accuracy of magnetic resonance imaging (MRI) in predicting knee bucket-handle meniscal tear (BHMT) reparability.

METHODS

Twenty-eight patients who underwent knee arthroscopy by a single surgeon for BHMT with prior MRI examination were included. BHMTs were diagnosed by MRI based on the association of a displaced meniscal fragment on coronal images and one of the following three signs on sagittal slices: flipped meniscus sign, double posterior cruciate ligament, and meniscal fragment within the intercondylar notch. BHMT patients' MRIs were retrospectively reviewed independently to search for criteria of reparability by 2 observers with different degrees of experience in musculoskeletal radiology, and disagreements were arbitrated to consensus. The criteria for BHMT reparability were as follows: (1) rim width of less than 4 mm; (2) tear length of 1 cm or greater, regardless of total lesion length; and (3) generation of isosignals by the inner meniscal fragment and peripheral rim compared with the normal contralateral meniscus of the same knee. The first 2 criteria indicate an adequate meniscal lesion length in the vascularized zone (only the peripheral third), enabling meniscal healing after repair; the third criterion guarantees that the meniscus is nondegenerative.

RESULTS

Of the BHMTs, 5 (17.9%) were arthroscopically reparable and 23 (82.1%) were not. Interpretation of magnetic resonance images correctly predicted reparability in 4 of 5 reparable BHMTs and irreparability in 22 of 23 irreparable BHMTs (26/28 lesions). Interobserver agreement was good for the prediction of reparability (kappa = 0.7).

CONCLUSIONS

These results suggest that knee BHMTs that are predicted to be reparable by MRI would have a high likelihood of actually being reparable.

LEVEL OF EVIDENCE

Level II, development of diagnostic criteria on basis of consecutive patients and gold standard.

Magnetic resonance arthrography

For decades, fluoroscopic arthrography was the only method available to image a joint with contrast enhancement. Advances in CT led to the natural development of CT arthrography. Development of MRI and its capability for multiplanar imaging led to direct magnetic resonance arthrography (MRA). This technique has been performed since 1987 and has surpassed CT arthrography in popularity in the United States. Indirect MRA developed subsequently to offer a less invasive alternative. This article presents an overview of direct MRA and addresses joint-specific issues regarding direct MRA. An overview of indirect MRA also is provided.

Optimization of indirect arthrography of the knee by application of external heat: Initial experience

PURPOSE

To examine the potential utility of applying heat to increase the uptake of intravenous gadolinium (Gd) contrast into the knee joint in order to optimize MR arthrography.

MATERIALS AND METHODS

At 1.5T, 16 knees in eight patients without prior surgery, injury, or pain were examined before and 30 minutes after intravenous administration of Gd contrast (0.1 mM/kg). Between scans a heating pad was applied to the anterior aspect of eight randomly selected knees (the contralateral knee served as the control). Initial and postcontrast imaging consisted of identical axial T1-weighted sequences (TR/TE = 500/14 msec) without fat suppression. On the initial and postcontrast images, regions of interest (ROIs) were placed at identical locations in the suprapatellar pouch and the intercondylar notch by a reader blinded to the treated side. The values at these two locations were averaged and the change in joint signal intensity was calculated. The differences between the heated and unheated knees were also calculated.

RESULTS

Seven of the eight knees treated with heat had increased joint enhancement compared to the contralateral control, with percentage changes in joint signal intensity (heated knee vs. control) of +38%, +80%, +121%, +145%, +150%, +164%, and +177%. Overall there was a doubling of signal intensity (125%) on the heated side compared to the contralateral control (with significance at P = 0.039). One patient was excluded because of a prior knee injury.

CONCLUSION

The application of external heat increases uptake of intravenously administered Gd contrast into the knee joint, and may help to optimize indirect MR arthrography at a relatively low cost.