The hinge effect in the knee joint is produced by the rounded femoral condyles and the shallow depressions of the tibial plateaus. The tibial spine is a twin-peaked projection that lies between and separates the tibial plateau. Lying on top of the tibia are two incomplete rings of semilunar-shaped pieces (or C-shaped wedges) of fibrocartilage that are known as the medial and lateral menisci. The menisci cover some one half to two thirds of the articular surfaces of each tibial plateau. The menisci move forward and backward with the tibia and promote a snug fit between the femur and the tibia when the joint is in extension. The main functions of the menisci are weight bearing and joint stability, and they also serve a proprioceptive role in the knee (Schoen, 2000).
With the present emphasis on increased physical activity, there has been an increased need for comprehensive reconstruction and restoration of knee function. Meniscal injury is a well-recognized source of knee dysfunction. Thus, arthroscopic treatment of meniscal pathology has become one of the most common orthopaedic procedures.
The shift from meniscectomy to the preservation and repair of the meniscus results from a better understanding of the biomechanical and functional properties of the intact meniscus in relation to knee mechanics and patient outcomes. The menisci increase the surface for femoral-tibial load bearing, facilitate the mechanics of joint lubrication, and act as a secondary anterior-posterior stabilizer. Maintaining an intact and functioning meniscus is a major factor in reducing the risk of developing arthritis. Therefore, the goal is to maintain physiologic knee kinematics as much as possible.
The five research articles reviewed in this article address different issues related to the meniscus of the knee. The first article by Wadey et al. argues that meniscal lesions are common but also difficult to diagnose. Their research tested the positive predictive value (PPV) of posterior joint-line tenderness (JLT) in diagnosing meniscal tears without knowing the patient's history. The second article by Camanho et al. acknowledged that meniscal injuries occur with different etiologies, and they designed their study to evaluate the results of arthroscopic meniscectomy treatment of patients with isolated meniscal injuries of different etiologies. The third article by Tuckman et al. determined the success rate of meniscal repair achieved in their clinic using all-inside repair devices. The fourth article addresses the association of meniscal pathological changes with cartilage loss in symptomatic knee osteoarthritis. The last article looks at arthroscopic treatment of symptomatic discoid meniscus in children.
Schoen, D. C. (2000). Adult orthopaedic nursing (p. 319). Philadelphia: Lippincott Williams & Wilkins.
Wadey, V. M. R., Mohtadi, N. G. H., Bray, R. C., & Frank, C. B. (2007). Positive predictive value of maximal posterior joint-line tenderness in diagnosing meniscal pathology: A pilot study. Canadian Journal of Surgery, 50(2), 96-100.
The authors view meniscal lesions as common but difficult to diagnose. Historically, the diagnosis was made by using a combination of a history and physical tests, one being the McMurray Test. However, controversy continues regarding whether there is a single clinical diagnostic test that is most sensitive and specific to correctly diagnose meniscal tears.
The purpose of this study was to determine the positive predictive value (PPV) of posterior joint-line tenderness (JLT) in diagnosing posterior meniscal tears. They hypothesized that if maximal tenderness was located along either posterior joint line, then meniscal pathology would be found on arthroscopic examination at that specific site in more than 80% of the patients examined.
The study investigated the effectiveness of one isolated clinical test (JLT), without the benefit of a case history or a complete physical examination. The authors focused on JLT in predicting meniscal pathology and compared it to the gold standard of arthroscopy in a prospective manner. In addition, they wanted to assess interobserver reliability of JLT to describe how well findings could be applied to other observers.
The study consisted of 71 consecutive patients who presented to the orthopaedic surgeons of the University of Calgary's Sport Medicine Centre in Canada. In the preoperative holding area, without taking a history and before sedation, the tibiofemoral joint line was systematically palpated to record the point of maximal tenderness. By using proper hand positioning over the joint line, the examination consisted of: (a) the joint line being palpated by passively flexing the knee joint to 90[degrees]; (b) identifying hollows that lie over the joint line at the side of the patellar ligament; (c) identifying the soft hollow between the prominence of the femur above and the tibia below; (d) palpating the joint line of the knee starting from the medial border of the patellar ligament and palpating toward the posterior aspect of the knee, then applying the same technique along the lateral aspect of the knee; (e) palpating the borders of the tibial plateau and femoral condyles to determine the presence of isolated posterior JLT; and (f) palpate the borders of the patella.
To assess for interobserver reliability on each patient, two additional experienced but similarly blinded examiners performed the same palpation maneuver without taking a history. The two examinations were performed independently of each other to eliminate information bias. Each patient then had an arthroscope of the knee, and findings were documented on a standard arthroscopy report form.
A statistical analysis was performed to compare JLT data with arthroscopic data. Of the 71 subjects, 45 were male and 26 female, and all were between 19 and 66 years old. The PPV of JLT for diagnosing meniscal tears was 60%, with 33 of 55 patients with positive JLT having a meniscal tear. The nonpositive predictive value (NPV) was 62.5%, with 10 of 16 subjects with no JLT not having a meniscal tear. Thus, the overall sensitivity of JLT in detecting meniscal tears was 84.6%, but the specificity was only 31.2%. In 75.8% of patients, all three examiners found the same point of maximal tenderness. Based on a kappa score of 0.48, that suggests that the interobserver reliability was good.
The authors failed to confirm their hypothesis of accurately diagnosing meniscal tears 80% of the time. The small sample size restricts the usefulness of the study. Another major limitation of this approach to diagnosing meniscal tears was the deliberate exclusion of use of the history in diagnosing, a questionable methodology. The patient history may identify other pathologies besides meniscal tears that need to be addressed. Furthermore, by studying patients who were preselected for surgery, the investigators likely increased their sensitivity in determining the association between JLT and meniscal pathology.
Camanho, G. L., Hernandez, A. J., Bitar, A. C., Demange, M. K., & Camanjo, L. F. (2006). Results of meniscectomy for treatment of isolated meniscal injuries. Correlation between results and etiology of injury. Clinics, 61(2), 133-138.
Meniscal injuries occur with different etiologies. The injury may occur (a) as part of a rotational trauma; (b) as a result of bending, as a consequence of a degenerative process; or (c) as a spontaneous injury caused by fatigue. Regardless of the etiology, the same symptomatology results, with similar clinical manifestations and treatments, although different therapeutic results are expected.
The purpose of this study, which was conducted at the University of Sao Paulo Medical School in Brazil, was to evaluate the results of the treatment of patients with isolated meniscal injuries of different etiology. The objective was to verify the natural history of a group of patients with isolated meniscal injuries and relate the different etiologies to the treatment results.
The study comprised 435 patients (261 male and 174 female) with isolated meniscal injuries who were monitored for 4 years. The age range was 50 to 59 years (average age 57). The most frequently affected side was the right side, and the most frequently injured meniscus was the medial meniscus. All injuries affected the medial femoral condyle, and all patients with fatigue injuries were females.
The diagnosis was obtained clinically and confirmed by nuclear magnetic resonance imaging (MRI). All patients underwent x-rays of their affected knee, and those with radiographic signs of osteoarthritis were excluded from the study. Ninety-two patients showed chondral injuries on MRI, but that was not viewed as an exclusion criterion. Clinical evaluation was based on palpation maneuvers of the articular femur-tibia interline, first with the knee bent to 90[degrees] and second associated with bending-extension movements.
Using the clinical history, the patients were divided into three groups according to etiology: (a) traumatic injury (194 patients), (b) degenerative injury (101 patients), and (c) injury resulting from fatigue (140 patients). All patients underwent arthroscopic meniscectomy. During the first 6 months, the follow-up was done during office visits, and, subsequently, patients were evaluated through telephone calls for up to 4 years.
Taken as a whole, the outcome of the meniscectomy for the treatment of isolated meniscal injuries provided good results as 363 of the patients benefitted. However, in 71 patients, the results were rated poor. Of those 71, 15 were in the traumatic group, 43 were in the degenerative group, and 13 in the fatigue group.
Meniscectomy as a treatment for degenerative meniscal injury provided unsatisfactory results in 42.5% of the cases-a much higher proportion than for the other two groups.
Although the patients with chondral injuries were not excluded from the study, the study results showed that chondral injuries lead to less satisfactory results. Thus, the benefit of having a meniscectomy for patients with chondral injury or degenerative etiology is unclear based on the results of this study.
Tuckman, D. V., Bravman, J. T., Lee, S. S., Rosen, J. E., & Sherman, O. H. (2006). Outcomes of meniscal repair: Minimum of 2-year follow-up. Bulletin of the Hospital for Joint Diseases, 63(3&4), 100-104.
With the shift from meniscectomy to preservation and repair of the meniscus, maintaining an intact functioning meniscus, reducing the risk of developing arthritis in the knee, and maintaining physiologic knee kinematics as much as possible, newer all-inside repair devices have been used.
The purpose of this New York City retrospective chart review with telephone follow up was to determine the success rate of meniscal repair achieved in the authors' sport medicine practice, particularly the outcomes observed with the newer all-inside repair devices. The authors aimed to determine if any specific patient factors contributed to success or failure with these various meniscal repair techniques. They were also aware that other reports on the outcomes of meniscal repair varied based on the method of evaluation and the technique being evaluated.
The retrospective chart review was performed, identifying 157 patients who had undergone a meniscal repair procedure between 1996 and 2001. Twenty-four were lost to follow-up and excluded from the study, leaving 133 patients (a follow-up rate of 85%). The patient records were from four board-certified surgeons, and the study was restricted to patients with a minimum of 2 years of follow up. The mean age was 30.1 years (range 8-58). The study considered 110 medial meniscal repairs and 23 lateral repairs. The time from injury to surgery was divided into: less than 6 weeks (acute) or greater than 6 weeks (chronic). Only 99 patients had duration of injury available: 48 were acute and 51 chronic.
Etiology of the meniscal tear was divided into three categories: sports-related trauma, non-sports trauma, and atraumatic. One hundred two (76%) were sports trauma, 24 (18%) were non-sports trauma, and 8 (6%) were classified as atraumatic. Indications for the surgery were full-thickness vertical longitudinal meniscus tears greater than 1 cm long. Repair techniques used included outside-in sutures, inside-out sutures, darts, arrows, meniscal screws, T-fix, FasT-fix, and RapidLoc.
Patient charts were reviewed for demographic and surgical information, including patient age at repair, sex, mechanism of injury, length of preoperative symptoms, tear length, tear location, concomitant procedures, presence of chondral injury, repair technique used, complications, postoperative rehabilitation protocol, length of follow up, and whether the patient underwent a revision surgical procedure. Patients were contacted by telephone. For this study, failure was defined as revision surgery for the same tear that was initially repaired and that occurred in the absence of a new traumatic insult.
The results showed a failure rate of 36%. There was no association found between failure and the length of preoperative symptoms, rim width, etiology, or concomitant menisectomy, chondroplasty, or anterior cruciate ligament (ACL) reconstruction. There was a higher rate of failure for tears in the medial versus lateral meniscus (20.3% vs. 44.8%). No statistical comparisons could be made between devices.
This was an interesting study with good intentions. However, the sample size (157) was far too small to test the eight different repair techniques. The authors needed to have performed a power test to determine the sample size needed to achieve statistical significance. Another weakness in the study was the use of telephone interviews instead of physical examination of the postsurgical knees. The larger but unanswered question is why simplifying the procedure with newer meniscal repair devices does not lead to an increased success rate.
Hunter, D. J., Zhang, Y. Q., Niu, J. B., Tu, X., Amin, S., Clancy, M., et al. (2006). The association of meniscal pathologic changes with cartilage loss in symptomatic knee osteoarthritis. Arthritis & Rheumatism, 54(3), 795-801.
Osteoarthritis (OA) knee cartilage loss is a multifactorial process that is influenced by systemic risk factors, such as age, sex, and obesity, and by local mechanical factors, such as alignment and injury. Important local mechanical factors are the integrity and functioning of the meniscus. The meniscus has many functions, including load bearing, shock absorption, stability enhancement, and lubrication. A diagnosis of knee OA after meniscectomy is traditionally considered a result of the joint injury that led to the meniscectomy. A meniscectomy is often accompanied by the onset of OA because of the high focal stresses imposed on the articular cartilage and subchondral bone subsequent to excision of the meniscus. Numerous studies have confirmed the importance of loss of meniscal function as a risk factor in subsequent knee OA.
Because meniscectomy is an important risk factor for OA, what about the effect of meniscal tears and meniscal extrusion or subluxation on cartilage loss in knees with preexisting OA? The objective of this study was to explore the role of meniscal tears and meniscal malposition as risk factors for subsequent cartilage loss in subjects with symptomatic OA before the meniscectomy.
Subjects for the study were patients with symptomatic knee OA from the Boston Osteoarthritis of the Knee Study. Patients were asked two questions: "Do you have pain, aching, or stiffness in one or both knees on most days?" and "Has a doctor ever told you that you have knee arthritis?" Patients who answered yes to both questions were followed up with an interview in which they were asked about other types of arthritis that could cause knee symptoms. If no other forms of arthritis were identified, then the individual was eligible for the study.
Each patient in the study had a series of knee radiographs (posteroanterior, lateral, and skyline) to determine whether OA was present. If there was an osteophyte on any view in the symptomatic knee, the patient was eligible for the study. At baseline, each patient underwent magnetic resonance imaging (MRI) of the more symptomatic knee. Both the MRI and the radiographic studies were repeated at 15- and 30-month follow-up visits. Cartilage and meniscal damage were scored on MRI in the medial and lateral tibiofemoral joints using the semiquantitative whole-organ MRI score. At baseline assessment the patients were weighed, without their shoes, on a balance-beam scale, and height was assessed. Tibiofemoral cartilage was scored on MR images of all five plates of each tibiofemoral joint, and the meniscal position was measured using eFilm Workstation software. A proportional odds logistic regression model with generalized estimating equations was used to assess the effect of two dichotomous predictors, meniscal position factor and meniscal damage, on cartilage loss in each of the five plates within a compartment. Models were adjusted for age, body mass index (BMI), tibial width, and sex.
The authors assessed 257 subjects with a mean age of 66.6 years and BMI of 31.5 kg/m2; 42% were female, and 77% of knees had a Kellgren/Lawrence (K/L) radiographic severity grade >=2 (those with K/L grades of <2 had patellofemoral OA). At baseline, the majority (86%) of the knees had cartilage morphologic abnormalities in the medial tibiofemoral compartment, and 63% had morphologic abnormalities in the lateral compartment. In the medial tibiofemoral joint, each measure of meniscal malposition was associated with an increased risk of cartilage loss. The results also showed a strong association between meniscal damage and cartilage loss.
This study demonstrates the strong association between meniscal position, meniscal damage, and cartilage loss. It shows that each aspect of meniscal abnormality has a major effect on the amount of cartilage lost. The authors even state that the study clearly demonstrates the importance of meniscal damage for MRI-assessed cartilage loss.
The importance of an intact and functioning meniscus in patients with knee OA is highlighted in this study. It also shows that abnormal meniscal function has consequences for the rate of cartilage loss. However, the study has some limitations. They are: (a) the use of a semiquantitative measure of meniscal damage that does not distinguish the type of tear, as that may be important for cartilage loss; (b) failure to allow for clear delineation of the type of tear; and (c) confounding constructs by including displacement as a variable. In present-day practice, efforts are being made to preserve damaged menisci rather than remove them. Because of the importance of an intact and functioning meniscus, an industry for meniscal replacement is being developed within orthopaedics.
Good, C. R., Green, D. W., Griffith, M. H., Valen, A. W., Widmann, R. F., & Rodeo, S. A. (2007). Arthroscopic treatment of symptomatic discoid meniscus in children: Classification, technique, and results. Arthroscopy: The Journal of Arthroscopic and Related Surgery, 23(2), 157-163.
The discoid meniscus, first described in 1889, is a morphologic abnormality of the knee occurring almost exclusively on the lateral side. Classic symptoms are pain, popping, snapping, and decreased knee extension. The most common classification includes three major meniscal abnormalities: (a) a complete disk-shaped meniscus with a thin center covering the tibial plateau, (b) an incomplete semilunar-shaped meniscus with partial tibial plateau coverage, and (c) a Wrisberg-type, meniscus resulting from deficient posterior tibial attachments.
Early treatment included total meniscectomy, but current treatment commonly involves arthroscopic partial meniscectomy to reshape the meniscus (saucerization), in conjunction with the repair of any detached or unstable fragment. Complete meniscectomy is usually avoided because of the high rate of osteoarthritic changes seen at long-term follow-up. More recent reports have provided significant variability in lateral discoid meniscal morphology, attachment, and stability.
The purpose this study was to review the operative findings and early results for children and young adults treated arthroscopically for symptomatic discoid lateral menisci and also to propose a formal classification scheme that would consider both meniscal morphology and meniscal stability.
This retrospective study used the medical records and radiographic studies of all patients (27 patients and 30 knees) treated arthroscopically for symptomatic discoid meniscus by two surgeons between 1998 and 2002 at the Hospital for Special Surgery in New York City. Surgery was on the right knee for 21 patients, on the left for nine, and on both knees for two patients.
Data included sex, age at the time of surgery, type and duration of preoperative symptoms, preoperative and postoperative range of motion, postoperative symptoms, length of surgery, complications, type of postoperative brace or cast used, postoperative physical therapy, need for further surgery, and length of follow up. Discoid meniscal morphology was recorded using the three major meniscal abnormalities.
Mean age at surgery was 10.1 years (range 3 to 20) in 19 female and eight male patients.
Patients were treated arthroscopically, with arthroscopic saucerization successful in 28 of 30 knees. In two cases with large complex tears, meniscal salvage was not possible and a complete meniscectomy was done. Twenty-two cases had complete and eight had incomplete meniscal tears. Meniscal instability was noted in 23 of 30 knees, with anterior horn instability in 16, posterior instability in five, and combined anterior and posterior instability in two.
The results of the study show the short-term efficacy of arthroscopic saucerization and repair to the capsule in selected cases of symptomatic discoid menisci. However, on the basis of this study and recent reports documenting a high rate of anterior horn instability, the authors propose an arthroscopic classification system for discoid lateral menisci. Menisci would be classified as complete or incomplete discoid and then subclassified based on the presence of instability as a result of deficient capsular attachment and, finally, based on the location of the absent capsular attachment.
Although the study is small and retrospective, there appears to be value in the results and the classification system presented. Further research needs to be done in this area to improve the quality of patient care and outcomes in cases of discoid menisci.