Posterior Horn Tears Research Articles

An Ayurvedic approch to Knee Ligament Injury - A case study

Knee joint is heavily stressed joint in the body. It has two completely incompatible properties of stability and mobility. It heavily depends on quadriceps femoris and collateral ligaments for stability. Due to increasing number of accidents and sports injuries, knee ligament injuries are also increasing in number, which more commonly occurs in anterior cruciate ligament (ACL), medial collateral ligament (MCL) and meniscus. However, surgical reconstruction does not guarantee a previous level of activity. In this single case study an effort is made to manage knee ligament injury through Ayurveda. A 38 years old female suffering from anterior cruciate ligament tear and complex tear in body and posterior horn of medial meniscus was treated with Janu basti and internal medicine. The duration of the treatment was 30 days, which provided relief from pain with noticeable improvement in the movement of knee joint.

Effects of creating a tunnel through intercondylar fossa under arthroscopy for the treatment of complex tears at the medial meniscus posterior horn

To discuss the advantages of the arthroscopic treatment for complex tears of the medial meniscus posterior horn by creating a tunnel passageway through the intercondylar fossa. All 127 patients including 24 males and 103 females with complex tears at the medial meniscus posterior horn were reviewed. The age of all patients ranged from 45 to 78 years old, with an average of 67 years old. All 127 patients were treated with partial meniscectomy, in which 112 patients were treated with partial meniscectomy smoothly with three incisions (anterior medial incision, anterior lateral incision, high anterior lateral incision), and 15 patients were treated with four incisions (anterior medial incision, anterior lateral incision, high anterior lateral incision, posterior medial incision). Four aspects were estimated:whether the meniscus posterior horns could be observed totally and conveniently, whether tools could be pushed to target area conveniently, the damage of adjacent cartilages, operation time(the operation time of partial meniscectomy). Posterior horns of all patients were totally and conveniently observed, tools were conveniently pushed to the target area in all cases, and all the cases had no iatrogenic injuries at adjacent cartilages. The operation time of partial meniscectomy at posterior horns with three incisions ranged from 5 to 10 minutes, and it ranged from 10 to 30 minutes with four incisions. It is very convenient and fast of the arthroscopy to treat complex tears of the medial meniscus posterior horn by creating a tunnel through the intercondylor fossa. Iatrogenic injuries of the adjacent cartilages were prevented to the greatest extent.

ARTHROSCOPICALLY ASSISTED TREATMENT OF POSTERIOR CRUCIATE LIGAMENT AVULSION FRACTURE WITH MENISCUS POSTERIOR HORN TEAR

To evaluate the effectiveness of arthroscopically assisted treatment of posterior cruciate ligament (PCL) tibial eminence avulsion fractures associated with meniscus posterior horn tear. Between January 2012 and December 2014, 21 patients with PCL avulsion fracture and meniscus posterior horn tear were arthroscopically treated with polyester suture and hollow screw fixation. There were 10 males (10 knees) and 11 females (11 knees), aged 14-53 years (mean, 35.7 years). The causes included sport injury in 11 cases, traffic accident injury in 9 cases, and daily life injury in 1 case. Based on the anteroposterior and lateral X-ray films, CT, and MRI, PCL avulsion fractures were diagnosed, and 2 cases had anterior cruciate ligament avulsion fractures. The results of posterior drawer test were positive in all patients, with no end point in 14 cases and with soft end point in 7 cases; all patients showed tibial sink. The preoperative International Knee Documentation Committee (IKDC) score and Lysholm score were 46.5±5.5 and 43.3±4.5 respectively. The time from injury to operation was 6-22 days (mean, 10 days). The operation time was 60-100 minutes (mean, 75 minutes). Primary healing of incision was obtained in all patients, without no complication of infection. The mean follow-up time was 27.4 months (range, 12-46 months). The results of posterior drawer test were negative in 19 cases, and positive in 2 cases (having hard end point). Tibial sink disappeared. At last follow-up, X-ray film showed good healing of fracture, and no displacement. The patients had no locking knee, snapping or tenderness of joint space, and the Mcmurray sign was negative; the IKDC score and Lysholm score were significantly improved to 92.0±2.5 and 92.7±2.6 respectively (t=-39.903, P=0.000; t=-43.242, P=0.000). The range of motion was normal in 20 patients (0-130°) except 1 patient having limited flexion (0-80°), whose range of motion returned to 0-120° after release. The arthroscopic fixation technique has satisfactory results for the reduction and fixation of PCL avulsion fracture associated with meniscus posterior horn tear because of easy operation, firm fixation, and economic price.

Meniscal Extrusion in the Knee: Should only 3 mm Extrusion be Considered Significant? An Assessment by MRI and Arthroscopy.

Aim. The aim of this study was to assess whether significant meniscal extrusion of more than 3 mm or of even lesser degrees of extrusion could be considered significant. We also aimed to determine the morphology of tears that are most likely to be associated with significant extrusion.Study design and material. The study was done retrospectively on a group of 202 patients (157 males and 45 females) who had been seen in our hospital between 2007 and 2011 with meniscal tears (in one knee only) diagnosed by MRI and confirmed on arthroscopy. Extrusion of 3 mm or more (usually considered significant) was seen in 102 cases and less than 3 mm in 100. Extrusion was measured on the coronal MR images rather than on saggital images because of ease and reproducibility. The tears were confirmed by arthroscopy and correlated with the extent of extrusion on MRI.Results: Out of the total of 202 cases, 102 cases (50.5%) had extrusion of 3 mm or more on MRI. Of these, the medial meniscal posterior horn tears accounted for 63 cases (64.26%), 21 cases were medial meniscal body tears (21.42%), five medial meniscal root tears (5.1%), nine lateral meniscal body tears (9.18%) and four lateral meniscal posterior horn tears(4.08%). Forty-four cases had extrusion of 3-4 mm, 26 had extrusion of 4-5mm, 17 cases had extrusion of 5-6mm, ten had extrusion of 6-7mm and five had extrusion of 7 mm or more. One hundred cases fell in the < 3mm extrusion category, of which 80 (39.6%) were in the 2-3 mm extrusion group and 20 (9.9%) in the 1-2 mm extrusion group. They comprised of 61 cases of medial meniscal posterior horn tears, 23 cases of medial meniscal body tears, six medial meniscal root tears, eight lateral meniscal body tears and two lateral meniscal posterior horn tears. The highest proportion of meniscal tears was seen in the 2-3 mm category comprising nearly 40% of the entire study group. The majority of tears were medial meniscal posterior horn tears.Conclusion: Menisci that extruded 2-3 mm from the tibial margin formed a major proportion of menisci treated for tears by repair or menisectomy. We should consider extrusion of more than 2mm as significant. Most tears had extrusion of 2-4 mm.

Clinical Evaluation of the Root Tear of the Posterior Horn of the Medial Meniscus in Total Knee Arthroplasty for Osteoarthritis.

PurposeTo investigate the incidence of root tears of the posterior horn of the medial meniscus in total knee replacement arthroplasty for knee osteoarthritis and retrospectively analyze clinical results and factors associated with root tears.Materials and MethodsThere were 197 knees of 140 enrolled patients who had undergone total knee replacement arthroplasty between September 2010 and May 2014. The presence of a root tear of the posterior horn of the medial meniscus was confirmed in all patients. Statistical analysis was performed to investigate the correlation between root tears and the possible factors of meniscal tears including gender, age, severity of symptoms (visual analogue scale [VAS] score and medial joint line tenderness), grade of osteoarthritis (Kellgren-Lawrence grading scale), body mass index (BMI), varus deformity, and mechanical axis deviation.ResultsMeniscal tears were observed in 154 knees (78.17%). The root tear had correlation with the severity of osteoarthritis (p<0.05), varus deformity (p<0.05), mechanical axis deviation (p<0.05), and BMI (p<0.05).ConclusionsFactors considered to represent the severity of osteoarthritis were found to be associated with root tears of the medial meniscus posterior horn. Increased BMI seemed to be associated with the increased incidence of root tears of the medial meniscus posterior horn.

THU0193 White Meniscus Sign is Associated with Degeneration of Cartilage in Pre-Radiographic Osteoarthritis

BackgroundOsteoarthritis (OA) is a heterogeneous disease characterized by joint degeneration including the progressive loss of hyaline articular cartilage. One of the challenges in diagnosis and management of OA is the...

The prevalence of knee injuries ipsilateral to tibial shaft fractures and their impact on clinical outcome.

The purpose of this prospective study was to examine the prevalence of occult knee injuries in patients with ipsilateral tibial shaft fractures and determine their impact on clinical outcome. Preoperative knee MRI examination was performed in 41 patients (42 knees) with isolated tibial shaft fractures. Menisci, cruciate ligaments, collateral ligaments, extensor mechanism, osteochondral lesions, bone contusions and knee effusion were evaluated. All patients were treated with reamed and locked intra-medullary tibial nailing without an additional surgical procedure for knee injuries. All patients were followed to at least fracture union and were evaluated with knee examination and Lysholm knee score. Of the 42 knees, 41 (97.6 %) showed at least one defined injury around the knee. There was only one patient who had totally normal knee MRI findings. One or more ligamentous injuries of the knee were identified in 35 (83.3 %) of the knees. Five patents (11.9 %) had medial meniscal tear in posterior horn. Extensor mechanism injuries were seen in two patients. Mild to marked joint effusion was observed in 35 (81 %) knees. Twenty-two knees demonstrated bone bruise; femoral condyle (n = 7), tibial plateau (n = 12), patella (n = 2) and fibular head (n = 1). No patients had osteochondral lesion. Patients were followed with a mean of 13.2 ± 3.6 (range 8-22) months. Clinical knee examination revealed Grade II (+) anterior drawer test in two patients. The mean Lysholm knee score was 99.1 ± 2.14 (range 91-100) at the final follow-up. Ipsilateral intra-articular, extra-articular or combined knee injuries may occur at the time of injury with tibial shaft fractures. However, most of these injuries are not clinically relevant and heal without any sequel or remain asymptomatic late after fracture union. Routine use of preoperative knee MRI examination in patients with tibial shaft fractures is not necessary.

Medial meniscus posterior horn zones show differing responses to static loading in subjects with knee osteoarthritis compared to controls

Medial meniscus posterior horn zones show differing responses to static loading in subjects with knee osteoarthritis compared to controls

Clinical, Radiological, and Morphological Evaluations of Posterior Horn Tears of the Lateral Meniscus Left In Situ During Anterior Cruciate Ligament Reconstruction

Background: Recent studies have shown that lateral menisci have a higher healing potential and that they can be treated successfully without symptoms by being left in situ during anterior cruciate ligament (ACL) reconstruction. However, few studies have reported morphological results. Hypothesis: Stable posterior horn tears of the lateral meniscus left in situ during ACL reconstruction could be healed spontaneously and would result in not only successful clinical outcomes but also morphological restoration. Study Design: Cohort study; Level of evidence, 3. Methods: Among 367 patients who underwent primary ACL reconstruction between 2008 and 2010, 53 patients who had lateral meniscus tears that were left in situ were analyzed. These patients were evaluated subjectively and radiologically and compared with a matched control group that underwent ACL reconstruction without any other structural disorders. Of the 53 patients with stable posterior horn tears of the lateral meniscus left in situ, 28 patients were assessed by second-look arthroscopic surgery and magnetic resonance imaging (MRI). Results: The mean follow-up of the study group and the control group was 36.47 and 37.26 months, respectively. There were no statistical differences in postoperative clinical outcomes between the 2 groups. Clinical results of both groups including the Lysholm score, Tegner activity score, and International Knee Documentation Committee (IKDC) score significantly improved. In the subgroup composed of 28 patients, follow-up MRI showed 25 (89%) and 24 (86%) healed menisci in sagittal and coronal views, respectively. Twenty-one (75%) were considered to be completely healed, and 5 (18%) were incompletely healed on second-look arthroscopic surgery. Conclusion: Stable posterior horn tears of the lateral meniscus left in situ at the time of ACL reconstruction revealed successful clinical outcomes compared with isolated ACL injuries and showed considerable healing and functional restoration of tears with repeat MRI and second-look arthroscopic surgery. Therefore, leaving stable posterior horn tears of the lateral meniscus in situ during ACL reconstruction should be considered.

Medial extrusion of the posterior segment of medial meniscus is a sensitive sign for posterior horn tears

BackgroundTo evaluate medial extrusion of the posterior segment of the medial meniscus in posterior horn tears. MethodsThis study enrolled 72 patients without medial meniscal tears (group N), 72 patients with medial meniscal tears without posterior horn tears (group PH−), 44 patients with posterior horn tears of the medial meniscus (group PH+). All meniscal tears were confirmed by arthroscopy. Medial extrusion of the middle segment and the posterior segment was measured on coronal MRIs. ResultsExtrusions of both middle and posterior segments in groups PH− and PH+ (middle segment; 2.94±1.51mm for group PH− and 3.75±1.69mm for group PH+, posterior segment; 1.85±1.82mm for group PH− and 4.59±2.74mm for group PH+) were significantly larger than those in group N (middle segment; 2.04±1.20, posterior segment; 1.21±1.86). Both indicators of extrusion in group PH+ were larger than those in group PH−. In the early OA category, neither middle nor posterior segment in group PH− extruded more than in group N. However, only the posterior segment in group PH+ extruded significantly more than in group N. Multiple lineal regression analyses revealed that posterior segment extrusion was strongly correlated with the posterior horn tears (p<0.001) among groups PH− and PH+. ConclusionThe newly presented indicator for extrusion of the posterior segment of the medial meniscus is associated with posterior horn tears in comparison with the extrusion of the middle segment, especially in the early stages of osteoarthritis. Level of EvidenceLevel II - Diagnostic Study

Meniscal Extrusion and Spontaneous Osteonecrosis With Root Tear of Medial Meniscus: Comparison With Horizontal Tear

The incidence of root tears in patients with spontaneous osteonecrosis of the knee has been studied, but the incidence of spontaneous osteonecrosis of the knee in patients with medial meniscus root tears has not. We assessed the latter incidence and evaluated the characteristics of medial meniscus root tears by comparing clinical status, the degree of osteonecrosis, and meniscal extrusion in patients with horizontal tears. Sixty-three patients who were diagnosed with medial meniscus posterior horn tear and treated by arthroscopic surgery between March 2005 and March 2009 were evaluated retrospectively. Patients were divided into 2 groups, the root tear group (R group) and the horizontal tear group (H group). Functional scores and radiography, simple radiography, and magnetic resonance imaging were investigated. No significant differences in age, body mass index, and symptom duration were observed between the 2groups. The incidence of osteonecrosis was 12 of 36 knees (33.3%) in the R group and 4 of 27 (14.8%) in the H group. The mean absolute extrusion was 4.1 ± 0.7 mm and 3.5 ± 1.4 mm in the R and H groups, respectively (P= not significant). The mean relative percentage of extrusion in the R group (46.1% ± 9.0%) was greater than that in the H group (35.3% ± 13.2%) (P= .01). The degree of osteonecrosis (ellipsoidal volume) was also greater in the R group (423.1 ± 236.7 mm(3)) than that in the H group (175.8 ± 43.6 mm(3)) (P= .03). Though not significant, the visual analog pain score had a tendency to be more severe and knee scores had a tendency to be lower in the R group than in the H group. Medial meniscus root tears had a greater degree of meniscal extrusion and wider osteonecrosis than horizontal tears of the posterior horn related to loss of the main function of the meniscus. Level III, retrospective comparative study.

Second-Look Arthroscopic Findings After Open-Wedge High Tibia Osteotomy Focusing on the Posterior Root Tears of the Medial Meniscus

This study examined, at second-look arthroscopy, the results of open-wedge high tibial osteotomy (HTO) focusing on root tear of the medial meniscus posterior horn (RTMMP). Among 31 consecutive patients who underwent HTO without a meniscectomy or pullout repair for RTMMP, 20 patients were available for second-look arthroscopic evaluation. All patients had medial unicompartmental arthritis. The healing status of the RTMMP was classified as complete, incomplete, and no healing. The difference in the weight bearing line from presurgery to the last follow-up was evaluated. Osteoarthritis and chondral lesions were evaluated, as were clinical results. Correlations between healing status and other variables (weight bearing line, cartilage status, and clinical scores) were assessed. The healed (10 patients) and nonhealed (incomplete 6 patients+ no healing 4 patients) groups were also evaluated with respect to other variables. There were 10 (50%) cases with complete healing, 6 (30%) with incomplete healing, and 4 (20%) with no healing. Kellgren-Lawrence grade did not improve according to the standing plain radiograph (P=.09). Progression of chondral lesions was not observed at second-look arthroscopy; some improvement was even observed (P= .002). The median Lysholm score improved from 58 preoperatively to 88.5 at the last follow-up. The median Hospital for Special Surgery (HSS) score also increased significantly from 62.4 (range, 50 to 76) to 87.2 (range, 80 to 92; P= .003). The comparison between healed and nonhealed groups revealed no statistical differences in all variables. This study revealed a high rate of healing of RTMMP after HTO without attempted repair. Healing of the meniscus was not associated with an improved clinical outcome. Level IV, therapeutic case series.

Accuracy of 3-Tesla Magnetic Resonance Imaging for the Diagnosis of Intra-articular Knee Injuries in Children and Teenagers

Magnetic resonance imaging (MRI) is a commonly used tool for the diagnosis of intra-articular knee pathologies. Although many studies have reported the accuracy of MRI in the adult population, fewer studies have investigated these tests in younger patients. Furthermore, these studies have shown a higher variability in both the sensitivity and the specificity of MRI for these knee injuries in this age group. Advancements in MRI technology, such as the 3-Tesla (3T) MRI magnet, have shown promising results for musculoskeletal injury diagnosis in adults. This study aims to evaluate 3 T MRI for the diagnosis of intra-articular knee pathologies in a pediatric and adolescent patient population. The records of 116 patients (119 knees) under the age of 20 years who underwent 3 T MRI studies of the knee and subsequent knee arthroscopy were reviewed retrospectively. The MRI report from the musculoskeletal radiology staff, the interpretation from the staff orthopedic surgeon, and the operative note dictations were compared, with a focus on meniscus and anterior cruciate ligament (ACL) pathologies. Seventeen orthopedic staff reads were not obtainable. Arthroscopy was used as the gold standard for diagnosis. The average age at MRI exam was 16.0 years and at surgery was 16.2 years. Using the musculoskeletal radiologist interpretation, the sensitivity and the specificity of 3 T MRI were 81.0% and 90.9% for medial meniscus injuries, 68.8% and 93% for lateral meniscus injuries, and 97.9% and 98.6% for ACL injuries, respectively. The orthopedic surgeon's interpretation of 3 T MRI had a sensitivity and specificity of 75.7% and 92.4% for medial meniscus injuries, 69.8% and 98.3% for lateral meniscus injuries, and 100% and 98.6% for ACL injuries, respectively. Posterior horn tears had the greatest discrepancies. When performed on pediatric and adolescent patients, newer 3 T MRI studies have excellent accuracy for diagnosing ACL tears. These studies also show a higher accuracy for the diagnosis of medial meniscal tears than lateral meniscal tears. Diagnostic study--Level 2.

Trabecular bone structure and spatial differences in articular cartilage MR relaxation times in individuals with posterior horn medial meniscal tears

To analyze knee trabecular bone structure and spatial cartilage T(1ρ) and T(2) relaxation times using 3-T magnetic resonance imaging (MRI) in subjects with and without tears of posterior horn of the medial meniscus (PHMM). 3-T MRI from 59 subjects (>18 years), were used to evaluate PHMM tears based on modified Whole-Organ Magnetic Resonance Imaging Score (WORMS) scoring; and to calculate apparent trabecular bone-volume over total bone volume fraction (app. BV/TV), apparent trabecular number (app. Tb.N), apparent trabecular separation (app. Tb.Sp) and apparent trabecular thickness (app. Tb.Th) for overall femur/tibia and medial/lateral femur/tibia; and relaxation times for deep and superficial layers of articular cartilage. A repeated measures analysis using Generalized Estimating Equation (GEE) was performed to compare trabecular bone and cartilage relaxation time parameters between people with (n = 35) and without (n = 24) PHMM tears, while adjusting for age and knee OA presence. Subjects with PHMM tears had lower app. BV/TV and app. Tb.N, and greater app. Tb.Th, and app. Tb.Sp. They also had higher T(1ρ) times in the deep cartilage layer for lateral tibia and medial femur and higher T(2) relaxation times for the deep cartilage layer across all compartments. PHMM tears are associated with differences in underlying trabecular bone and deep layer of cartilage. Over-load of subchondral bone can lead to its sclerosis and stress shielding of trabecular bone leading to the resorptive changes observed in this study. The results underline the importance of interactions of trabecular bone and cartilage in the pathogenesis of knee OA in people with PHMM tears.

Paper 69: The Effect of Pullout Suture For the Radial tear of Posterior Horn of Medial Meniscus in Porcine Knee

PurposeThe radial tear of the meniscus results in the loss of hoop tension which may lead to the premature degenerative changes of knee joint. The effect of current pullout suture techniques on radial tear of posterior horn of medial meniscus(PHMM) is unknown. The aim of this study is to measure the contact pressures of medial compartment of the knee joint after pullout suture in radial tear of PHMM.

Meniscal pullout repair following meniscal ossicle resection: A case report

We present this case of a meniscal ossicle of the posterior horn of the medial meniscus that was treated by an arthroscopic ossicle resection followed by a pullout repair of the remaining meniscus. A 49-year-old businessman complained of catching and left knee pain. Radiographic and arthroscopic findings revealed a meniscal ossicle embedded in the posterior horn of the medial meniscus and posterior horn tear. After resection of the posterior horn with the ossicle, a pullout suture repair for the posterior segment of the meniscus was done to minimize the further extrusion of the meniscus. A histologic appearance supported the vestigial development of the meniscal ossicle as the etiology. This is the first report describing a repair of the meniscus after ossicle resection.

Modified Pull-out Suture in Posterior Root Tear of the Medial Meniscus: Using a Posteromedial Portal

In cases with root tear of the medial meniscus posterior horn, the meniscus usually can be repaired by a pull out suture technique. However, there is difficulty in manipulating a suture hook via the anteromedial portal and looking through the arthroscopic camera via anterolateral portal in the narrow medial joint space at the same time. This article describes a modified simple pull out suture technique for root tear of the medial meniscus posterior horn using a posteromedial portal that provides a safe and easy handling of the suture hook. Our indications of this technique used in patients with Outerbridge 1-2 arthritic change and minimal varus axis change. Benefits of this technique are simple, less invasive, and reduced operation time by simultaneous suture with a hook via posteromedial portal and pulling of a string with grasper. It may reduce the possibility of an additional chondral or meniscal injury.

Paper # 148: Microfracture for Focal Full-Thickness Articular Cartilage Defect of Medial Femoral Condyle in Old Aged Osteoarthritis

Arthroscopic microfracture for full-thickness articular cartilage defect of medial femoral condyle in old patients produced worse results compared with meniscectomy alone. The purpose of this study was to determine the effectiveness of the microfracture technique for the treatment of focal full-thickness cartilage lesions of the medial femoral condyle in the degenerative arthritis. This study included 40 patients with symptomatic medial meniscus tears, single full thickness cartilage defect on medial femoral condyle and age over 60 years old. Exclusion criteria was Kellgrene-Lawrence grade IV osteoarthritis, varus alignment over 5 degree and lateral compartment cartilage defect. Mean age was 62.8 years (range, 60- 69 years) and there were 36 female and 4 male patients. Only partial medial meniscectomy was done and preserved the subchondral bone integrity without microfracture in 20 patients (group I). Partial medial meniscectomy and microfracture on medial femoral condyle were performed in 20 patients (group II). Follow up period was minimum of 12 months (mean, 16 months; range, 12 to 38 months). Knee function was evaluated with Lysholm score and joint space narrowing was evaluated with anteroposterior plane radiographs taken at postoperative 1 year. Medial meniscus tears were degenerated posterior horn tear in all patients and treated with partial meniscectomy. The size of medial femoral cartilage lesion was 1.7 cm2 (1.0 to 3.2 cm2) and located on weight bearing dome in the range of 10 to 90 degree knee flexion. No difference in the size was found in both groups. In group I, Lysholm scores were 58 preoperatively and improved as 86 at final follow up. In group II, Lysholm scores were improved as 72 from 55. The knee function evaluated with Lysholm score was significantly improved in group I (p= 0.0073). Joint space was decreased in both groups. But in group II, joint space narrowing was progressed faster from 3 months after operation and more severe. In group II, total knee arthroplasty was performed eventually in 3 patients due to severe pain on medial compartment. Arthroscopic microfracture for full-thickness articular cartilage defect of medial femoral condyle in old patients produced worse results compared with meniscectomy alone. One hypothesis is that microfracture can lead to distruction of subchondral bone integrity that was important for sustaining weight loading. Even though the technique of microfracture have advantages like procedure simplicity and low morbidity, the principles of technique and protection from full weight bearing after surgery should be kept for preventing the destruction of subchondral bone integrity.

Longitudinal Tear of the Medial Meniscus Posterior Horn in the Anterior Cruciate Ligament–Deficient Knee Significantly Influences Anterior Stability

Background: Longitudinal tears of the medial meniscus posterior horn (MMPH) are commonly associated with a chronic anterior cruciate ligament (ACL) deficiency. Many studies have demonstrated the importance of the medial meniscus in terms of limiting the amount of anterior-posterior tibial translation in response to anterior tibial loads in ACL-deficient knees. Hypothesis: An MMPH tear in an ACL-deficient knee increases the anterior-posterior tibial translation and rotatory instability. In addition, MMPH repair will restore the tibial translation to the level before the tear. Study Design: Controlled laboratory study. Methods: Ten human cadaveric knees were tested sequentially using a custom testing system under 5 conditions: intact, ACL deficient, ACL deficient with an MMPH peripheral longitudinal tear, ACL deficient with an MMPH repair, and ACL deficient with a total medial meniscectomy. The knee kinematics were measured at 0°, 15°, 30°, 60°, and 90° of flexion in response to a 134-N anterior and 200-N axial compressive tibial load. The rotatory kinematics were also measured at 15° and 30° of flexion in a combined rotatory load of 5 N·m of internal tibial torque and 10 N·m of valgus torque. Results: Medial meniscus posterior horn longitudinal tears in ACL-deficient knees resulted in a significant increase in anterior-posterior tibial translation at all flexion angles except 90° (P < .05). An MMPH repair in an ACL-deficient knee showed a significant decrease in anterior-posterior tibial translation at all flexion angles except 60° compared with the ACL-deficient/MMPH tear state (P < .05). The total anterior-posterior translation of the ACL-deficient/MMPH repaired knee was not significantly increased compared with the ACL (only)–deficient knee but was increased compared with the ACL–intact knee (P > .05). A total medial meniscectomy in an ACL-deficient knee did not increase the anterior-posterior tibial translation significantly compared with MMPH tears in ACL-deficient knees at all flexion angles (P > .05). In a combined rotatory load, tibial rotation after MMPH tears or a total medial meniscectomy in an ACL-deficient knee were not affected significantly at all flexion angles. Conclusion: This study shows that an MMPH longitudinal tear in an ACL-deficient knee alters the knee kinematics, particularly the anterior-posterior tibial translation. MMPH repair significantly improved anterior-posterior tibial translation in ACL-deficient knees. Clinical Relevance: These findings may help improve the treatment of patients with ACL and MMPH longitudinal tear by suggesting that the medial meniscal repairs should be performed for greater longevity when combined with an ACL reconstruction.

Anterior Knee Laxity Increases Gapping of Posterior Horn Medial Meniscal Tears

Background Meniscal tears often occur in association with anterior cruciate ligament (ACL) lesions or in chronically lax knees. It is also known that meniscal repairs are less likely to heal in ACL-deficient knees. Purpose To test the effect of different knee joint motion and loading conditions on the gapping behavior of longitudinal posterior horn meniscal tears in stable and ACL-deficient knee joints. Study Design Controlled laboratory study. Methods Longitudinal tears of 3 cm were set in the posterior horn of the medial menisci in 10 human cadaveric joints. The medial plateau of the knees was replaced by a transparent replica, and an arthroscope was placed underneath to observe the gapping phenomenon of the meniscal tears. The maximum gap width occurring during flexion-extension under various motion and loading situations was registered in intact and ACL-deficient joints before and after meniscal repair with FasT-Fix suture anchors. Results Longitudinal meniscal tears gapped significantly wider after ACL transection under 30-N axial joint load (P < .05). Increasing the axial load to 200 N or applying external moments to the knee did not lead to further alterations in the gap size. Gapping was significantly reduced after meniscal repair (P < .01). However, after meniscal repair, gapping under 30-N and 200-N axial joint load was still increased significantly after ACL transection compared with the ACL-intact state (P < .05). Conclusion Anterior knee laxity increases gapping across both unrepaired and repaired vertical peripheral medial meniscal posterior horn tears. Clinical Relevance Repairing such meniscal tears without reconstructing the ACL may affect meniscus healing rates or increase the risk of retears. Moderate rehabilitation regimens can be recommended, allowing at least for partial weightbearing and knee motion from extension to 120° of flexion in a stable knee. However, caution should be recommended if meniscal repair is performed in a knee joint with persistent anterior laxity due to ACL deficiency.