Bony morphology of the knee and non-traumatic meniscal tears: Is there a role for meniscal impingement?

Objective

Meniscal tears are an important cause of morbidity. The aim of this study was to examine the relationship between non-traumatic meniscal tears and the intrinsic bony morphology of the knee.

Methods

A retrospective analysis of 160 knee MRI scans in 150 patients was carried out who met the following criteria: (a) age between 20 and 45 years, (b) no history of knee trauma, surgery, infection, metabolic bone disease, and (c) no collateral or cruciate ligamentous injury. The medial tibial slope (MTS), lateral tibial slope (LTS), medial tibial plateau depth (MTPD), and medial and lateral femoral condylar offset ratios were calculated. The anterior horn, body, and posterior horn of the menisci were graded as 0 (no tear), 1 and 2 (degenerative changes), or 3 (definitive tear). One-way ANOVA and linear regression was used for statistical analysis.

Results

In patients with grade 3 tears of the posterior horn of the medial meniscus, there was a significant association with shallower MTS (p?<?0.05), smaller medial femoral offset ratio (p?<?0.05) and smaller lateral femoral offset ratio (p?<?0.05). Patients with grade 3 tears of anterior horn of the lateral meniscus had a significant association with shallower LTS (p?<?0.05). No significant association was seen between MTPD and meniscal tears.

Conclusions

Our results suggest an association between bony morphology of the knee and non-traumatic meniscal tears. Shallower MTS and LTS may result in impingement of posterior horn of medial meniscus and anterior horn of lateral meniscus, respectively. Future kinematic studies will be needed to help confirm our findings.     

Reliability of magnetic resonance imaging in evaluating meniscal and cartilage injuries in anterior cruciate ligament-deficient knees

Purpose

The accuracy of magnetic resonance (MR) imaging in assessing meniscal and cartilage injuries in anterior cruciate ligament (ACL)-deficient knees as compared to arthroscopy was evaluated in the present study.

Methods

The results of all preoperative MR imaging performed within 3 months prior to the ACL reconstruction were compared against intraoperative arthroscopic findings. A total of 206 patients were identified. The location and type of meniscal injuries as well as the location and grade of the cartilage injuries were studied. The negative predictive value, positive predictive value, sensitivity, specificity and accuracy of MR imaging for these 206 cases were calculated and analysed.

Results

In patients with an ACL injury, the highest incidence of concomitant injury was that of medial meniscus tears, 124 (60.2 %), followed by lateral meniscus tears, 105 (51.0 %), and cartilage injuries, 66 (32.0 %). Twenty-three (11.2 %) patients sustained injuries to all of the previously named structures. MR imaging was most accurate in detecting medial meniscus tears (85.9 %). MR imaging for medial meniscus tears also had the highest sensitivity (88.0 %) and positive predictive value (88.7 %), while MR imaging for cartilage injuries had the largest specificity (84.1 %) and negative predictive value (87.1 %). It was least accurate in evaluating lateral meniscus tears (74.3 %). The diagnostic accuracy of medial meniscus imaging is significantly influenced by age and the presence of lateral meniscus tears, while the duration between MR imaging and surgery has greater impact on the likelihood of lateral meniscus and cartilage injuries actually being present during surgery. The majority of meniscus tears missed by MR imaging affected the posterior horn and were complex in nature. Cartilage injuries affecting the medial femoral condyle or medial patella facet were also often missed by MR imaging.

Conclusion

MR imaging remains a reliable tool for assessing meniscus tears and cartilage defects preoperatively. It is most accurate when evaluating medial meniscus tears. However, MR imaging should be used with discretion especially if there is a high index of suspicion of lateral meniscus tears.

Level of evidence

IV.

     

Comparison of T1rho relaxation times between ACL-reconstructed knees and contralateral uninjured knees

Purpose

The goal of this study is to compare the cartilage of anterior cruciate ligament (ACL)-reconstructed and uninjured contralateral knees using T _1ρ MRI 12–16 months after ACL reconstructions.

Methods

Eighteen patients with ACL-reconstructed knees (10 women, 8 men, mean age = 38.3 ± 7.8 years) were studied using 3T MRI. Injured and contralateral knee MR studies were acquired 12–16 months post-operatively. Cartilage sub-compartment T _1ρ values of each injured knee were compared with the contralateral knee’s values. Subgroup analysis of sub-compartment T _1ρ values in both knees was performed between patients with and without meniscal tears at the time of ACL reconstruction using a paired Student’s t test.

Results

In ACL-injured knees, the T _1ρ values of the medial tibia (MT) and medial femoral condyle (MFC) were significantly elevated at 12–16 months follow-up compared to contralateral knees. Patients with a medial meniscal tear had higher MFC and MT T _1ρ values compared to respective regions in contralateral knees. Patients with lateral meniscal tears had higher lateral femoral condyle and LT T _1ρ values compared to respective regions in contralateral knees. There were no differences between the injured and contralateral knees of patients without meniscal tears.

Conclusions

T _1ρ MRI can detect significant changes in the medial compartments’ cartilage matrix of ACL-reconstructed knees at 1 year post-operatively compared to contralateral knees. The presence of a meniscal tear at the time of ACL reconstruction is a risk factor for cartilage matrix degeneration in the femorotibial compartments on the same side as the meniscal tear.     

Comparison of magnetic resonance imaging findings with arthroscopic findings in discoid meniscus

Purpose

It is widely accepted that although valuable in the diagnosis of the discoid meniscus and tears, magnetic resonance imaging (MRI) can be insufficient in determining the type of the tear. This study calculates the sensitivity and specificity of MRI in determining the presence and absence of tears and how these values differ for different types of tears.

Methods

This study is a retrospective review of 10 years of our experience with arthroscopic discoid meniscus treatment between 1999 and 2009. MRI findings were compared with the intraoperative arthroscopic findings in 52 patients with 50 lateral and two medial discoid menisci of which 24 were complete and 28 were incomplete. Tears were classified into six groups: (1) no tear, (2) simple horizontal tear, (3) radial tear, (4) combined horizontal tear, (5) complex tear and (6) longitudinal tear. Sensitivity, specificity, positive and negative predictive values of MRI were calculated for each group separately and for the presence and absence of tears in general. In addition, the effect of age, type of discoid meniscus, and presence and absence of shift on the distribution of tear types were analysed.

Results

MRI was found to be 100 % specific and 97.8 % sensitive for determining the presence or absence of a tear with a negative predictive value of 85.7 % and a positive predictive value of 100 %. The specificities were 80 % for simple horizontal, 50 % for radial, 66.7 % for combined horizontal, 55.6 % for complex and 14.3 % for longitudinal tears, whereas the sensitivities were 66.7 % for simple horizontal, 96.9 % for radial, 87.5 % for combined horizontal, 94.6 % for complex and 100 % for longitudinal tears. The presence and absence of shift and type of the discoid were found to affect the distribution of the tear type.

Conclusions

MRI is successful in determining the presence or absence of tears in discoid menisci; however, its ability to determine the tear type is questionable. Complete discoid menisci were found to have tendency towards having a simple horizontal or longitudinal tear, whereas incomplete discoid menisci tend to have radial or combined horizontal tears. Determination of the shift prior to surgery is important since it alters the surgical technique.

Level of evidence

I.     

The MRI findings of meniscal root tear of the medial meniscus: emphasis on coronal, sagittal and axial images

Purpose

The purpose of this study was to evaluate the accuracy of the characteristic magnetic resonance imaging (MRI) findings of medial meniscal root tear in the coronal, sagittal and axial planes.

Methods

Thirty arthroscopically diagnosed patients who had undergone preoperative knee MRI were included in this study. They were compared to 30 age-matched patients with medial meniscus tears without root tears. The findings used for imaging analysis were as follows: the radial tear on the meniscal root of the medial meniscus in the axial plane, the presence of the truncation sign in the coronal plane and the ghost meniscus sign in the sagittal plane. Meniscal extrusion in the coronal plane was also evaluated. All the MRI findings of both groups were statistically analyzed.

Results

All the findings were more frequently found in the root tear group than those in the control group (P < 0.05). The sensitivity, specificity, positive predictive value and negative predictive value of finding a radial tear in the axial plane were 93.3, 100, 100 and 93.8%, respectively. In the coronal plane, rates for the presence of the truncation sign were 90, 100, 100 and 90.9%, respectively. In the sagittal plane, rates for the presence of the ghost meniscus sign were 96.7, 96.7, 96.7 and 96.7%, respectively. The rates for the meniscus extrusion in the coronal plane were 63.3, 90, 86.4 and 71.1%, respectively.

Conclusions

The findings of medial meniscal root tear were characteristic as compared with the control group. Radial tear in the axial plane also showed similar diagnostic accuracy as that seen in the other planes. The characteristic findings provide high diagnostic accuracy, and axial plane is helpful to detect medial meniscal root tear.

Level of evidence

Diagnostic study, Level III.     

The shiny corner of the knee: a sign of meniscal osteochondral unit dysfunction

Objective

The purpose of this retrospective study is to describe the MRI findings of the “shiny corner” of the knee (bone marrow lesions at the meniscal-covered portions of the tibial plateau) and to determine its association with compromise of the medial meniscal-osteochondral unit.

Materials and methods

A retrospective review of 200 knee MRI exams was performed and images were evaluated in consensus by two musculoskeletal radiologists. Presence and location of a shiny-corner lesion was recorded, which was defined as a focal, peripheral hyperintense lesion on fluid-sensitive images at the superior portion of the medial tibial plateau. Meniscal and root ligament abnormalities were recorded, including tearing, degeneration, and extrusion.

Results

Sixty exams demonstrated a shiny-corner lesion. Shiny corners involved the medial rim of the medial tibial plateau in 50 cases, only involved the posterior rim in seven cases, and only involved the anterior rim in two cases. Patients with shiny corners were older than patients without shiny corners (mean, 53 years vs. 44 years, p?=?0.01). The shiny-corner sign was associated with tears of the medial meniscus, root ligament, and meniscal extrusion (p?Conclusions Shiny-corner lesions of the knee are associated with tears of the menisci and root ligaments. This observation supports the concept that the menisci protect the underlying covered portions of the tibial plateau.     

Change of signal intensity in the displaced medial meniscus after its reduction on MRI

Purpose

To compare magnetic resonance (MR) signal intensity in the medial meniscus at the time of displacement and after its reduction in patients with a displaced bucket-handle tear of the meniscus associated with anterior cruciate ligament (ACL) injury.

Methods

Nine chronic ACL-deficient patients (3 male, 6 female, mean age 29 years) with locking due to a displaced fragment of the medial meniscus following a bucket-handle tear were involved in this study. In all patients, the following two-stage surgeries were planned as follows: first operation, arthroscopic reduction of the meniscus; second operation, meniscal repair and ACL reconstruction after immobilization for 1–2 weeks. Magnetic resonance imaging (MRI) evaluation using coronal T2*-weighted images was performed when the knee was locked and after the meniscus was reduced. Signal intensity before and after meniscal reduction was compared in the same patients.

Results

In 8 of the 9 patients, the displaced fragment exhibited high signal intensity in 1 patient and mildly high in 7 patients. After its reduction, the signal intensity changed to low in all 8 patients.

Conclusions

A high-intensity signal in the displaced fragment of the medial meniscus may change to low after its reduction to its original position. Therefore, at the time of decision-making regarding meniscus repair for a displaced meniscus in a locked knee, surgeons should give priority to arthroscopic findings rather than to signal intensity on MRI.

Level of evidence

Diagnostic study, Level III.     

A systematic review and meta-analysis of the diagnostic accuracy of MRI for suspected ACL and meniscal tears of the knee

Purpose

To determine the diagnostic accuracy of magnetic resonance imaging (MRI) and ultrasound (US) in the diagnosis of anterior cruciate ligament (ACL), medial meniscus and lateral meniscus tears in people with suspected ACL and/or meniscal tears.

Methods

MEDLINE, Web of Science and the Cochrane library were searched from inception to March 2014. All prospective studies of the diagnostic accuracy of MRI or US against arthroscopy as the reference standard were included in the systematic review. Studies with a retrospective design and those with evidence of verification bias were excluded. Methodological quality of included studies was assessed using the QUADAS-2 tool. A meta-analysis of studies evaluating MRI to calculate the pooled sensitivity and specificity for each target condition was performed using a bivariate model with random effects. Sub-group and sensitivity analysis were used to examine the effect of methodological and other study variables.

Results

There were 14 studies included in the meta-analysis of the accuracy of MRI for ACL tears, 19 studies included for medial meniscal tears and 19 studies for lateral meniscal tears. The summary estimates of sensitivity and specificity of MRI were 87 % (95 % CI 77–94 %) and 93 % (95 % CI 91–96 %), respectively, for ACL tears; 89 % (95 % CI 83–94 %) and 88 % (95 % CI 82–93 %), respectively, for medial meniscal tears; and 78 % (95 % CI 66–87 %) and 95 % (95 % CI 91–97 %), respectively, for lateral meniscal tears. Magnetic field strength had no significant effect on accuracy. Most studies had a high or unclear risk of bias. There were an insufficient number of studies that evaluated US to perform a meta-analysis.

Conclusion

This study provides a systematic review and meta-analysis of diagnostic accuracy studies of MRI and applies strict exclusion criteria in relation to the risk of verification bias. The risk of bias in most studies is high or unclear in relation to the reference standard. Concerns regarding the applicability of patient selection are also present in most studies.

Level of evidence

III.

     

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.     

The popliteus tendon provides a safe and reliable location for all-inside meniscal repair device placement

Purpose

Repairs of the posterior horn of the lateral meniscus can be technically challenging. In contrast to medial meniscus repairs, the capsule around the posterior segment attachment of the lateral meniscus is quite thin. This study evaluates the clinical results of an arthroscopic all-inside repair technique for unstable, vertical, lateral meniscus tears, using a suture repair placed directly into the popliteus tendon.

Methods

A retrospective analysis of prospectively collected data from the SANTI database was performed. All patients who had undergone combined ACL reconstruction with lateral meniscus all-inside repair, using sutures placed in the popliteus tendon, between 2011 and 2015, were included. Patients were reviewed clinically at 1 and 2 years’ follow-up. At final follow-up, all patients were contacted to identify if they underwent further surgery or had knee pain, locking or effusion. Symptomatic patients were recalled for clinical evaluation by a physician and Magnetic Resonance Imaging of the knee. Operative notes for those undergoing further surgery were reviewed and rates and type of re-operation, including for failed lateral meniscal repair were recorded.

Results

Two hundred patients (mean age 28.6?±?10.2 years) with a mean follow-up of 45.5?±?12.8 months (range 24.7–75.2) were included. The mean Subjective International Knee Documentation Committee (IKDC) at final follow-up was 85.0?±?11.3. The post-operative mean side-to-side laxity measured at 1 year was 0.6?±?1.0 mm. Twenty-six patients underwent re-operation (13%) at a mean follow-up of 14.8?±?7.8 months. The ACL graft rupture rate was 5.0%. Other causes for re-operation included medial meniscus tear (2.5%), cyclops lesion (1.5%) and septic arthritis (0.5%). The lateral meniscus repair failure rate was 3.5%. No specific complications relating to placement of sutures in the popliteus tendon were identified.

Conclusion

Arthroscopic all-inside repair of unstable, vertical, lateral meniscus tears using a suture placed in the popliteus tendon is a safe technique. It is associated with a very low failure rate with no specific complications.

Level of evidence

Level IV.

     

Delay in ACL reconstruction is associated with more severe and painful meniscal and chondral injuries

Purpose

The goal of our study was to investigate the associations between surgical delay, pain and meniscus, and articular cartilage lesions seen at the time of ACL reconstruction.

Methods

One hundred and sixty-two consecutive patients who had received ACL reconstruction were recruited. The preoperative International Knee Documentation Committee (IKDC) questionnaires, and cartilage and meniscal lesions seen at the time of surgery were analysed.

Results

Patients with surgery within 12 months were less likely to have meniscus injury (59.8/77.4 %, p = 0.032), and the meniscus injury was more likely to be salvageable. (56.3/36.0 %, p = 0.042). Patients with meniscal tear larger than 10 mm had higher pain intensity than tear <10 mm (mean 6.8/8.2, p = 0.007). Patients older than 35 years of age were more likely to suffer from cartilage injury (76.4/39.1 %, p = 0.004). Patients with cartilage lesions had longer surgical delay (mean 18.9/12.1 months, p = 0.033). The presence of meniscal tear increased the risk of cartilage lesions (p = 0.038, OR = 2.14). Patients with cartilage lesions had a greater pain frequency (mean 6.9/7.7, p = 0.048). Moderate correlation was found between the size of cartilage lesion and the frequency of pain (p = 0.013).

Conclusions

Increased surgical delay was associated with an increased incidence of meniscus and articular cartilage injuries in patients suffering from ACL tear; also, the meniscus was less likely to be salvageable. The presence of cartilage lesions was associated with an increased frequency of pain. Size of meniscal and cartilage lesions was significantly associated with pain.

Level of evidence

Retrospective comparative study, Level III.     

Displacing lateral meniscus masquerading as patella dislocation

Purpose

To alert the treating clinician to an uncommon knee meniscal condition that often masquerades as a more common patella condition.

Methods

Retrospective chart review of a series of cases was undertaken. A series of 12 knees in 11 patients were referred to an orthopaedic surgeon with a diagnosis of recurrent lateral patella dislocation. Three knees had undergone patella realignment surgery with continuance of symptoms. Eight patients had prior magnetic resonance images read as no meniscal pathology and no acute patella/patella retinacular injury. All patients presented for a consult with a similar history.

Results

Under anaesthesia, all knees had a stable patella as judged by physical examination. At the time of surgery, six patients had a frank tear in the lateral meniscus, all of which were readily displaceable. Six knees showed a displaceable lateral meniscus with attenuation but not a visible frank tear. Ten menisci were treated with repair, and two knees underwent partial lateral meniscectomies. Patient follow-up of minimally 18 months revealed no further episodes of “knee-cap dislocation” or symptoms of catching and locking.

Conclusions

The clinician treating a patient with a history of a knee locking in flexion should have a high index of suspicion for a lateral meniscus tear or an unstable hypermobile lateral meniscus, despite patient report of perceived patella movement. History of symptoms occurring in knee flexion and attention to patella physical examination should be key factors in this diagnostic conundrum.

Level of evidence

Retrospective chart review, Level IV.     

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.     

Meniscus repair with simultaneous ACL reconstruction demonstrated similar clinical outcomes as isolated ACL repair: a result not seen with meniscus resection

Purpose

To compare Knee Injury and Osteoarthritis Outcome Score (KOOS) and EuroQol-5D (EQ-5D) subscale scores at 2-year follow-up for patients with primary isolated ACL reconstruction with patients undergoing ACL reconstruction and simultaneous meniscal treatment in terms of either resection or repair in the Swedish National Knee Ligament Register (SNKLR).

Methods

All ACL reconstruction patients within the SNKLR at 2-year follow-up were reviewed. The KOOS and EQ-5D subscales were assessed in four distinct patient groups: isolated ACL reconstruction, ACL reconstruction?+?medial meniscus resection, ACL reconstruction?+?lateral meniscus resection, ACL reconstruction?+?medial meniscus repair, and ACL reconstruction?+?lateral meniscus repair. The primary analysis was conducted using linear regression with isolated ACL reconstruction designated as the reference group, and was adjusted for patient age, gender, and time from injury to surgery.

Results

The included patients consisted of 10,001 (65.0%) individuals with an isolated ACL injury, 588 (3.8%) with ACL injury plus treated with medial meniscus repair, 2307 (15.0%) with ACL injury plus treated with medial meniscus resection, 323 (2.1%) with ACL injury plus treated with lateral meniscus repair, and 2173 (14.1%) with ACL injury plus treated with lateral meniscus resection. Meniscus resection demonstrated significantly worse results with respect to the KOOS Symptoms subscale for both the medial and lateral meniscus resection groups. Medial meniscus resection also demonstrated worse results for the KOOS quality of life (QoL) subscale, while lateral meniscus resection only approached significance. Outcomes were not different between the isolated ACL reconstruction group and the meniscus repair groups.

Conclusion

Meniscus resection in addition to ACL reconstruction resulted in worse clinical outcomes than isolated ACL reconstruction patients; a result not seen within the meniscus repair group. This suggests that, when possible, meniscus repair may provide greater clinical outcomes over resection when treating a reparable meniscal tear that presents along with an ACL tear. Clinicians should consider and implement these findings for the management of future meniscus tear patients within their clinical practice.

Level of evidence

Level III.

     

MR imaging of meniscal tears: comparison of intermediate-weighted FRFSE imaging with intermediate-weighted FSE imaging

Purpose

We compared intermediate-weighted fast spin-echo (IW-FSE) images with intermediate-weighted fast-recovery FSE (IW-FRFSE) images in the diagnosis of meniscal tears.

Materials and methods

First, 64 patients were recruited, and the arthroscopic findings (n?=?40) and image analysis (n?=?19) identified 59 torn menisci with 36 patients. Both the diagnostic performance and image quality in assessing meniscal tears was evaluated for IW-FSE and IW-FRFSE images using a four-point scale. Signal-to-noise ratio (SNR) calculation was performed for both sets of images.

Results

IW-FRFSE image specificity (100?%) for diagnosing the posterior horn of the medial meniscus (MM) tear with reader 1 was significantly higher than that of IW-FSE images (90?%). Mean ratings of the contrast between the lesion and normal signal intensity within the meniscus were significantly higher for the IW-FRFSE image ratings than the IW-FSE images in most meniscal tears. Mean SNRs were significantly higher for IW-FSE images than for IW-FRFSE images (P?<?0.05).

Conclusions

IW-FRFSE imaging can be used as an alternative to the IW-FSE imaging to evaluate meniscal tears.     

A simple cinch is superior to a locking loop for meniscus root repair: a human biomechanical comparison of suture constructs in a transtibial pull-out model

Purpose

To determine the cyclic displacement and ultimate failure loads of two clinically relevant suture configurations for repair of medial and lateral meniscus root tears.

Methods

A total of 10 matched pair fresh-frozen, human meniscus specimens were randomly assigned to either simple cinch or locking loop meniscus–suture fixation techniques for transtibial pull-out repair in either medial (n = 10 matched pairs) or lateral (n = 10 matched pairs) meniscal root tears. The menisci were subjected to cyclic tensioning at 10–30 N for 1000 cycles at 0.5 Hz, and then post-cycling load to failure was performed at a tensile rate of 0.5 mm/s.

Results

For both the medial and lateral meniscus, there was significantly less displacement with the cinch stitch at 100, 500 and 1000 cycle counts (p < 0.05). In respect to ultimate load, there was no significant difference in type of repair between the two suture configurations. When comparing ultimate load to failure from the medial to the lateral side, the ultimate load to failure was significantly greater for both suture configurations in the lateral meniscus root repair (p < 0.05). However, there was no significant difference in cyclic displacement between the medial and lateral meniscus.

Conclusions

The cinch stitch was significantly better at resisting displacement compared to the locking loop stitch configuration, and had similar ultimate load to failure. The lateral meniscus root repair construct has higher failure loads compared to the medial meniscus, independent of suture configuration.

     

Which patients are less likely to improve during the first year after arthroscopic partial meniscectomy? A multivariate analysis of 201 patients with prospective follow-up

Purpose

To determine which specific factors influence the improvements in function and pain at the first year following arthroscopic partial meniscectomy.

Methods

Between 2012 and 2013, patients who had arthroscopic partial meniscectomy were included (n = 201) and followed prospectively before surgery and at 12 months. Multivariable stepwise analysis included preoperative variables (age, gender, limb side, height, weight, body mass index, comorbidities, smoking, Tegner activity scale, Lysholm knee score, preceding injury and duration of preoperative symptoms) and arthroscopic findings (degree of cartilage lesions, medial or lateral meniscus involvement, type of meniscal tear and concomitant cruciate tear). The Lysholm clinical score at the last follow-up and the time interval for substantial pain relief was modelled as a function of the above predictor variables.

Results

At the last follow-up, the mean Lysholm score improved by 14.6 points (95 % CI 10.4–18.8, P < 0.001), from 68.0 ± 16.1 to 82.6 ± 19.6 points and 153 (76 %) patients declared they were satisfied to have had the operation. The mean time interval for substantial pain relief was 3.5 ± 1.5 months. Females and patients with lower preoperative Lysholm score were correlated with lower post-operative Lysholm score, while females and patients with lateral meniscal tears (compared to medial meniscal tears) were correlated with longer recovery.

Conclusions

Arthroscopic partial meniscectomy improved pain and function at the first year post-operatively. Female gender, lateral meniscal tear and less favourable preoperative function were relatively correlated to worse post-operative function and longer rehabilitation time.

Level of evidence

IV.

     

Anterolateral ligament abnormalities in patients with acute anterior cruciate ligament rupture are associated with lateral meniscal and osseous injuries

Objective

To determine the frequency of anterolateral ligament (ALL) injury in patients with acute anterior cruciate ligament (ACL) rupture and to analyse its associated injury patterns.

Methods

Ninety patients with acute ACL rupture for which MRI was obtained within 8 weeks after the initial trauma were retrospectively identified. Two radiologists assessed the status of the ALL on MRI by consensus. The presence or absence of an ALL abnormality was compared with the existence of medial and lateral meniscal tears diagnosed during arthroscopy. Associated collateral ligament and osseous injuries were documented with MRI.

Results

Forty-one of 90 knees (46 %) demonstrated ALL abnormalities on MRI. Of 49 knees with intact ALL, 15 (31 %) had a torn lateral meniscus as compared to 25 torn lateral menisci in 41 knees (61 %) with abnormal ALL (p?=?0.008). Collateral ligament (p?≤?0.05) and osseous injuries (p?=?0.0037) were more frequent and severe in ALL-injured as compared with ALL-intact knees.

Conclusion

ALL injuries are fairly common in patients with acute ACL rupture and are statistically significantly associated with lateral meniscal, collateral ligament and osseous injuries.

Key Points

? ALL injuries are fairly common in patients with acute ACL rupture. ? ALL injuries are highly associated with lateral meniscal and osseous injuries. ? MRI assessment of ACL-injured knees should include evaluation of the ALL.

     

Similar failure rate in immediate post-operative weight bearing versus protected weight bearing following meniscal repair on peripheral,vertical meniscal tears

Purpose and hypothesis

Post-operative weight bearing after meniscal repair is a point of debate among physicians. This study sought to evaluate whether patients adhering to an immediate WBAT rehabilitation programme have a higher failure rate compared to those adhering to a more traditional, protected, NWB status following meniscal repair. The null hypothesis was that there would be no difference in failure between the two groups.

Methods

A retrospective review of meniscal repair patients greater than 5 years from surgery was performed for patients receiving meniscal repair treatment. Patients were categorized by post-surgical weight-bearing status, either NWB or WBAT, and then analysed for failure of repair. Failure was defined as re-operation on the torn meniscus. The study controlled for variables including age at surgery, sex, height, weight, and BMI, classification of tear type, acuity of the tear, repair location (medial or lateral), repair location within the meniscus, repair technique, and concomitant procedures.

Results

Re-operations were performed in 61 of 157 patients [38.9%]. There was no difference between weight-bearing groups for failure of meniscus repair (n.s.). The tears were acute vertical tears located in the posterior horn and body. For the 61 patients with re-operation, the average time to re-operation was 2.2 years with 10 [16%] > 5 years from surgery, 17 [28%] 2–5 years from surgery, and 34 [56%] < 2 years from surgery. In isolated meniscal repair patients (n = 62), there was no difference between weight-bearing groups for rate of re-operation (n.s.).

Conclusion

Weight bearing as tolerated after meniscal repair for peripheral, vertical tears does not result in a higher failure rate than traditional, non-weight bearing over a five-year follow-up period. The clinical relevance is that, based on these data, it may be appropriate to allow weight bearing as tolerated following meniscal repair of peripheral, vertical tears.

Level of evidence

Retrospective cohort study, Level III.

     

Percutaneous medial collateral ligament release in arthroscopic medial meniscectomy in tight knees

Purpose

Visualization and surgery of tears in the posterior medial meniscus are difficult in tight knees. Iatrogenic chondral lesions might cause serious morbidity, and residual tears may result in inadequate symptom relief. We evaluated the clinical and radiological results of superficial medial collateral ligament (MCL) release during arthroscopic medial meniscectomy in tight knees.

Methods

Eighteen patients [median age: 43 years (22–59); median follow-up: 8.3 months (6–12)] who underwent arthroscopic meniscectomy were included in the study. Patients with ligamentous injuries, severe chondral damage or meniscal repairs were excluded. Preoperatively, anteroposterior knee radiographs were obtained with 11-kg valgus stress using a specialized instrument. During the operation, if opening of the medial knee in 30° flexion under 11-kg valgus stress was inadequate, controlled release of the posterior portion of the MCL was performed using a 16-gauge needle. Intraoperative valgus stress was monitored using a specially designed lateral support with mounted load cell. MCL injury was evaluated both with magnetic resonance imaging (MRI) and valgus stress radiographs, which were obtained in the 1st week and 3rd and 6th months postoperatively to monitor healing of the elongated MCL.

Results

In all patients, meniscectomy could be performed with adequate visualization of the posterior medial meniscus and without iatrogenic chondral injury. The median medial joint space width on valgus stress radiographs was 7.1 mm preoperatively and 9.1, 8.0 and 7.2 mm in the 1st week, and 3rd and 6th months, respectively (p < 0.0001). On MRI, the injured structure was the posterior two-thirds of the MCL. Median Lysholm score, which was 42 points before the operation, had increased to 94 points at the final follow-up (p = 0.0002).

Conclusion

Controlled release of the MCL in tight knees allowed easier handling in posterior medial meniscus tears and a better understanding of tear configurations, avoiding iatrogenic chondral lesions. The MCL injury healed uneventfully.

Level of evidence

IV.