The document discusses meniscal tears in the knee, including their structure, function, causes, diagnosis, and treatment options. It notes that meniscal tears are commonly sports-related or due to motor vehicle accidents. While meniscal repair or conservative treatment are preferred to preserve meniscal tissue, partial meniscectomy is still a common option that allows for quicker return to activity compared to repair or no surgery. However, meniscectomy is associated with increased risk of osteoarthritis over the long-term. MRI is an important diagnostic tool but clinical exam also provides value in diagnosis.
1. Meniscal Tears and Their
Treatment
Robert S. Fawcett M.D., M.S.
York Hospital Family Medicine
Residency
York, PA
2. Objectives
• Discuss important points in history,
physical and testing that lead to a
diagnosis of damaged meniscus
• Understand the short and long term
outcomes of meniscectomy
• Discuss the benefits and implications of
surgical vs. conservative management of
meniscal tear
3. Epidemiology
• Overall incidence unknown, but surgical
incidence is 60-70 per 100,000 per year
• Most common orthopedic surgical
procedure
• 1/3 of meniscal tears are sports-related
(most of the rest from MVAs)
• 1/3 of meniscal tears associated with ACL
injury
4.
5. Structure of the Meniscus
• Medial is semicircular
– Moves 2-5 mm through full ROM
– Lack of motion may promote tears
– Fibers from the deep medial collateral
• Lateral almost a complete circle
– Moves ~1 cm through full ROM
• Both made of fibrocartilage
– 75% circumferential type 1 collagen fibers
– 25% radial fibers
7. Structure of the Menisci
• Vascular supply good in the most
peripheral 20% of the fibers
– Supplied by the geniculate arteries
• Inner 1/3 of the ring is avascular
– Relatively thin
– Nourished through synovial fluid
• Middle 1/3 of the ring is combination
8. Function of the Menisci
• Distribute load across the knee joint
– 2-4x body weight during walking
– 6-8x body weight during running
• Axial compression is converted to “hoop
stress”, or circumferential elongation in the
meniscus
• Lateral meniscus distributes more load than
medial meniscus, which contributes to
greater degeneration if disrupted
• Menisci deepen the socket of the tibial
plateau, contributing to stability of knee
9. • Wedge shape limits translation of femur on
tibial plateau
• Menisci forced posteriorly in flexion, anteriorly
in extension of the knee
• Menisci reduce stresses on the ACL
• Menisci force synovial fluid into articular
cartilage (helping to nourish the white zone)
during compression.
Function of the Menisci
10. Pathophysiology
• In acute knee injuries with ACL intact,
medial meniscal injury is 5 times more
likely than lateral
• In acute knee injuries with ACL ruptured,
lateral meniscus more likely to be involved
• If ACL is previously disrupted, lateral
meniscal injury is more likely than medial
• In repetitive deep squatting, medial
meniscus most likely to be injured (20:1)
11. History: the Key to Diagnosis
• Twisting on planted foot
– Inertial forces or external forces
• Acute effusion in acute injury
• Waxing and waning course with pain and
effusion intermittently in chronic injury
• The older the patient, the less likely that
history will be revealing
– More likely to occur with trivial trauma
– Difficult to distinguish from DJD
13. Thessaly Test?
• Done with pt standing, first on normal leg
• Flex knee 5 degrees, rotate body on fixed leg
back and forth 3 times, holding examiner’s
hands for stability
• Flex further to 20 degrees and repeat
• Repeat on affected leg
• Positive is pain at joint line or feeling of
locking or catching
14. Value of MRI as Diagnostic Tool
• Studies do NOT prove it superior to
composite clinical exam
• Many false positives appear
• MRI has high NEGATIVE predictive value
• Sensitivity and specificity keep getting
better as technology improves
• How will MRI result change treatment?
– No surgeon would touch a knee without one
– Helps with planning procedure
17. Treatment Options
• Total meniscectomy
• Partial meniscectomy
• Meniscal repair
– Inside out
– Outside in
– All inside
• Conservative (No operative intervention)
18. Consequences of Meniscectomy
• As early as 1948 Fairbanks noted
increased osteophyte formation and
femoral cartilage deterioration in
meniscectomized knees
• Total meniscectomy remained a common
procedure until the 1980’s
• In medial meniscectomy, load bearing
surfaces are halved, doubling stress on
tibial plateau
• If 15-30% of meniscus is removed, forces
between tibia and femur increase up to
350%
19. Meniscus Repair
• Used in longitudinal tears
• Many fixation devises, none better than
sutures, though some are faster
• Outside in, inside out, and all inside
technique
20. Criteria for Meniscal Repair
vs. Partial Meniscectomy
Criterion Repair Ptl. Meniscectomy
Distance
from rim
<3mm >3mm
Mobility of
fragment
Stable Mobile
Age of injury Recent Old
Ret. To Play Later Sooner
Age of
patient
Younger Older
21. Meniscus Repair--Recovery
• Pts must wear brace with pwb for 2 weeks
• Sedentary workers back to work in 1 week
• Laborers back in 6-8 weeks
• Athletes back in 12-16 weeks
• 76% “excellent” results after 10 years*
*
22. Partial Meniscectomy
• Done when tear involves interior 70%
• May be done when athlete wants to
resume activity ASAP
• Done with mobile fragments
• 10-35 minute arthroscopic procedure
under regional or general anesthetic
– Mobile areas removed
– Edges contoured to “prevent further tears”
• Immediate partial weight bearing allowed
• Crutches for 1-2 days
23. • Sedentary workers back to work in 1 week
• Laborers back in 2-4 weeks
• Athletes back in 2-6 weeks
• 88% “excellent” results at 15 years*
Partial Meniscectomy--
Recovery
*Burks RT, Metcalf MW, Metcalf RW; 15 yr f/u of arthroscopic partial meniscectomy;
Arthroscopy 1997; 13:673-9.
24. Conservative Therapy
• Not an option if knee locked, fragment not
reduced
• Symptom relief with post-exercise RICE
• Symptom relief with NSAIDS, immobilization
• Physical therapy focusing on closed chain
exercise of quadriceps and hamstrings
• Failure includes recurrent effusion, recurrent
locking or pain that interferes with ADLs
• No randomized trials
25. Conservative Study Result
• Retrospective review of 3612 arthroscopies
• Identified 80 “stable” tears (<3mm
movement) for whom nothing was done
• 70 were longitudinal, 10 were radial
• Only 6 needed subsequent surgery, 4 of
which had had additional trauma
• 32 patients had “second look” surgery
• 17/22 longit. tears, 0/6 radial tears healed
completely
Weiss CB, Lundberg M, DeHaven KD, Gillquist J; Non-operative
treatment of meniscal tears. JBJS 1989 71-A(6):811-22.
26. • “Stable” tears at ACL reconstruction left to
heal and 2nd
look removing ACL hardware
• Lateral: 74% healed, 6% incompletely
healed, 14% unhealed
• Medial: 56% healed, 6% incompletely
healed, 24% unhealed
• Healing rate was “length dependent”
Conservative Study Results
Yagashita et al. Am J Spts Med 2004 32(8):1953
27. Conservative Study Results
• 32 patients
• 30 lateral and 10 medial meniscal tears
along with 25 ACL tears and 7 PCL tears
• Arthroscoped initially with repeat at 3 mo.
• Lateral meniscus: 69% completely healed
and 18% incompletely healed
• Medial meniscus: 58% completely healed
and 0% incompletely healed
Ihara H, Miwa M, Takayanagi K, Nakayama A.
Clin Orthop Relat Res. 1994 Oct;(307):146-54.
28. Ihara: Results Without Surgery
Injury Results at 2nd
Look
Lat
Meniscus
69% healed completely,
18% healed partially
Medial
Meniscus
58% healed completely
0% healed partially
Ant. Cruc.
Ligment
80% healed “satisfactorily”
Post Cruc.
Ligament
3/7 (40%) healed “satisfactorily”
29. Cochrane Review 2002
• No evidence for comparing surgery to no
treatment
• Partial is better than total meniscectomy:
– Less operative time
– Enhanced recovery rate
– Improved long term stability
• Arthroscopic is better than open
meniscectomy
– Less operative time
– Quicker recovery post-op
• No long term advantages have been shown
30. Summary: What We Know
• The meniscus, torn or intact, helps to
stabilize and dissipate axial force in the knee
• Degenerative changes develop more
frequently in meniscectomized (total or
partial) than in normal knees (Williams,
others)
• When meniscal repairs fail, pts are often
engaging in the same activity as initial injury
• Longitudinal tears heal more readily than
radial tears and simple or bucket handle
tears heal more readily than complex ones
31. • Peripheral tears (in the vascularized area)
heal more readily than central tears (Noyes,
Krych)
• Meniscal tears are accompanied by ligament
tears in many cases
• Repairing both meniscus and ligaments
(when both injured) improves outcomes
(Noyes)
• Ligamentous pathology with meniscal tears
makes degenerative changes more likely
Summary: What We Know
32. What We Know
• Younger pts do better with meniscal repair
than older patients (Mintzer)
• Less surgery is better than more surgery
– Arthroscopy better than open
– Partial better than complete meniscectomy
(Cochrane)
33. What We Don’t Know
• Whether no surgery is better than less surgery
– Whether operating on stable radial tears improves
outcomes
– How to tell without surgery that conservative
treatment is a reasonable option
• Whether and how long to immobilize the acute
tear
• If a repair is undertaken, what timing and type of
repair has the best outcomes
• If no repair is done, whether and when to do a
“second look”
34. BibliographyKarachalios T, Hantes M, Zibis AH, et al. Diagnostic accuracy of a new clinical test (the
Thessaly test) for early detection of meniscal tears. J Bone Joint Surg 2005;87:955–
62.
Krych AJ, McIntosh AL, Voll, Michael AE, Stuart J, Dahm DL. Arthroscopic Repair of
Isolated Meniscal Tears in Patients 18 Years and Younger. Am. J. Sports Med. 2008;
36; 1283 originally published online Mar 4, 2008.
Manson TT, Cosgarea AJ. Meniscal injuries in active patients. Advanced Studies in
Medicine November-December 2004, 4(10):545-552.
Muellner T, Weinstabl R, Shabus R, Vecsei V, Kainberger F; The diagnosis of meniscal
tears in athletes: a comparison of clinical and magnetic resonance imaging
investigations. Am J Sports Med 1997; 25:7-12.
Ihara H, Miwa M, Takayanagi K, Nakayama A. Clin Orthop Relat Res. 1994 (307):146-
54.
Johnson MJ, et al. (1999). Isolated arthroscopic meniscal repair: A long-term outcome
study (more than 10 years). American Journal of Sports Medicine, 27(4): 44–49.
Mintzer CM, Richmond JC, Taylor J. Meniscal repair in the young athlete. Am J Sports
Med 1998;26:630-3.
Noyes FR, Barber-Westin SD. Arthroscopic repair of meniscal tears extending into the
avascular zone in patients younger than twenty years of age. Am J Sports Med
2002;30:589-600.
Weiss CB et al. Non-operative treatment of meniscal tears. JBJS 1989 71-A(6): 811-22.
Howell JR Handoll HHG. Surgical treatment for meniscal injuries of the knee in adults
(Cochrane Review). In: The Cochrane Library, Issue 3, 2002. Oxford: Update
Software.
Williams RJ et.al. MRI evaluation of isolated arthroscopic partial meniscectomy patients
at a minimum five year follow-up. HSSJ 2007 3:35-43.
Editor's Notes
The medial meniscus is somewhat semicircular in appearance. It is approximately 3.5 cm in length in the anteroposterior dimension and considerably wider posteriorly than it is anteriorly. Its radius of curvature varies, giving it greater length in the sagittal plane than in the coronal plane. The anterior horn is attached to the tibial plateau in the area of the anterior intercondylar fossa, 6 to 7 mm in front of the ACL insertion. An intermeniscal, or “transverse,” ligament is present in 64% of individuals; this connects the anterior horn (posterior fibers) of the medial meniscus and the anterior horn (anterior fibers) of the lateral meniscus.[65] The posterior horn attaches to the posterior intercondylar fossa between the attachments of the lateral meniscus and the posterior cruciate ligament (PCL). The medial meniscus is continuously attached to the joint capsule along the entire periphery. The coronary ligament represents the tibial portion of this capsular attachment. At its midpoint, the medial meniscus is firmly attached to the femur and tibia through a robust thickening in the capsule known as the deep medial collateral ligament.
Lateral Meniscus
The lateral meniscus covers a larger portion of the tibial surface than does the medial meniscus. Its radius of curvature remains fairly constant, giving the lateral meniscus an almost circular appearance. The anterior horn is attached anterior to the intercondylar eminence, just posterior and lateral to the ACL attachment with which it partially blends. The posterior horn attaches posterior to the intercondylar eminence, just in front of the posterior end of the medial meniscus. In 50% of individuals, anterior fibers of the posterior enthesis extend to the lateral aspect of the medial femoral condyle, forming the anterior meniscofemoral ligament (ligament of Humphry).[55][65] In 76% of cases, the posterior fibers of the posterior horn cross posterior to the PCL and attach to the intercondylar fossa of the medial femoral condyle, forming the posterior meniscofemoral ligament (ligament of Wrisberg).[55] The lateral meniscus has only a loose peripheral attachment to the capsule, which is interrupted by the popliteus tendon. Lateral meniscal variants, including the most recognized discoid meniscus, have a reported prevalence as high as 16.6% (see “Special Considerations”).[43]
--DeLee and DeLee
Blood supply thru plexus from superior and inferior geniculate arteries.
Anterior horn of med meniscus attaches ant to fibers of ACL
Posterior horn is wider and attaches just posterior to fibers of ACL
Laterally, mm is anchored to medial collateral fibers.
64% of people have transverse lig connecting med and lat menisci anteriorly
Med meniscus attached to joint capsule throughout its circumference, tightly at med collateral.
Ant and post horns of semicircular lat meniscus attach lat to lat fibers of ACL.
Lat men more loosely attached than medial.
Ligaments of Humphreys and Wrisberg attach from posterior portion of lat men, run adjacent to post CL, and attach to fem cond.
Medial meniscus is tethered to joint capsule and is less stable
Lat more likely than medial with ACL due to shift of lateral femoral condyle
Clinical examination is the primary diagnostic tool for intra-articular and meniscal injuries. The most common findings, similar to those of adults, are joint-line tenderness and effusion [7] [31] . Because of the diversity of pathology and the difficulty of examination in children in an acute setting, the diagnostic accuracy of clinical exam for meniscus tear has been shown to be as low as 29% to 59% in series with multiple examiners [5] [32] . In children, anteromedial or anterolateral joint-line pain may be caused by patellofemoral pain, patellar instability, iliotibial band friction, osteochondritis dissecans, or other lesions. Sensitivity of McMurray and Apley tests is estimated to be 58% with even lower specificity [5] . Two recent studies, by examiners with significant pediatric sports medicine experience, showed the diagnostic accuracy of clinical exams to be 86.3% and 93.5% overall [32] [33] . When medial meniscus tears were looked at alone, sensitivity and specificity of clinical exams were 62.1% and 80.7%, respectively [32] . Sensitivity and specificity for lateral meniscal tears were 50% and 89.2%, respectively [32] .
Comparison of knee magnetic resonance imaging findings in patients referred by orthopaedic surgeons versus nonorthopaedic practitioners .
Arthroscopy: The Journal of Arthroscopic & Related Surgery , Volume 18 , Issue 2 , Pages 201 - 205
P . Sherman , B . Penrod , M . Lane , J . Ward
Abstract
Purpose: To compare the percentages of normal magnetic resonance imaging (MRI) examination results and clinically significant knee abnormalities in patients referred for MRI of the knee by orthopaedic surgery residents and staff with those of patients referred by nonorthopaedic practitioners. Type of Study: Retrospective review of MRI findings. Methods: MRI reports of 754 patients (454 men and 300 women) were retrospectively reviewed; 373 patients were referred from the Department of Orthopaedic Surgery and 381 patients were referred from nonorthopaedic practitioners. The number of normal examination results, meniscal and ligament tears, chondral abnormalities, and Baker’s cysts was tabulated and analyzed using a χ-square injury analysis. Results: The rate of normal results for nonorthopaedic practitioners was 33.9% (129 of 381) compared with 15.3% (57 of 373) for orthopaedic surgeons (P &lt; .001). Nonorthopaedic surgeons referred 69.4% (129 of 186) of the patients who had normal examination results. The positive finding for a lateral meniscus tear was 29.2% (109 of 373) for orthopaedic surgeons compared with 19.1% (73 of 381) for nonorthopaedic practitioners, which was statistically significant (P = .002) in regard to the distribution of injuries. No difference was found in other abnormalities assessed. Conclusions: Patients referred by nonorthopaedic practitioners had significantly more normal knee MRI examination results than did those referred by orthopaedic surgeons.
Tears are seen as high-grade signal areas within the substance of the meniscus. Radiologists user grading system to delineate these signal changes, with grade 0 being normal meniscus, grade 1 and 2 high signal intrameniscal areas that do not abut the free meniscal edge, and grade 3 high signal area that tracks to the edge of the meniscus. Grade 3 changes are the only changes consistent with clinically significant meniscal tear and, for this reason, care must be used when interpreting MRI images and reports. Care must also be used when interpreting signal changes in a patient who has had previous meniscal surgery, as MRIis often unreliable in these cases.
It is now appreciated that menisci serve many functions, including increasing contact area and congruency of the femoral-tibial articulation. The menisci load-share and reduce contact stresses across the joint. It is estimated that menisci transmit up to 50% to 70% of the load in extension and 85% in 90° of flexion [21] . Baratz and Fu showed that, following total menisectomy, the contact area decreased by 75% and contact stresses increased 235% [22] . They also documented deleterious effects of partial menisectomy, demonstrating that contact stresses increased in proportion to the amount of meniscus removed. Excision of narrow bucket-handle tears of the medial meniscus increased contact stress by 65%, and 75% resection of the posterior horn increased contact stresses equivalently to that of total menisectomy [22] . Repair of meniscal tears reduced contact stresses to normal. Other studies corroborate the mechanical importance of the meniscus [
Inside out most useful in posterior or lateral tears.
Outside in most useful for anterior tears.
All inside techniques involve specialized darts or anchors or arrows with methods of insertion and are not as secure
Some small, nondisplaced meniscal tears in the outer vascular region may heal spontaneously or become asymptomatic [5] [17] [18] . Nonoperative treatment consists of rehabilitation of the injured knee with the avoidance of pivoting and sports for 12 weeks.
The majority of meniscal tears in pediatric patients are large and require surgical treatment [5] [17] [18] . Arthroscopic management is standard with partial menisectomy (Fig. 2) or meniscal repair using outside-in, all inside (Fig. 3) , or inside-out techniques (Fig. 4) [17] [18] [36] . We believe that, in children and adolescents, meniscal repair should be attempted, instead of partial menisectomy, for middle third and outer third meniscal tears because of the theoretical greater healing potential at this age. Long life span and poor results of total and near-total menisectomy, and lack of longer-term results of partial menisectomy, encourage meniscal salvage attempts. Inside-out techniques are useful for anterior horn medial or lateral meniscal tears (Fig. 4) . Meniscal-body and posterior-horn tears are repaired b the traditional inside-out repair with vertical or horizontal sutures. Zone-specific cannulas can direct the flexible suture needles to appropriate positions to avoid neurovascular structures. We routinely make an incision posteromedially or posterolaterally to identify and retrieve the suture needles and tie the sutures at the joint capsule, protecting the saphenous nerve and vein medially and the peroneal nerve laterally. Newer all-inside devices have facilitated meniscal repair in adults (Fig. 3) . Reports of articular cartilage damage from heads of bioabsorbable arrows and darts exist [17] [18] and many of the devices extend too far through the capsule in a pediatric knee, with potential for pain and neurovascular injury. We prefer more recent all-inside low-profile suture devices for posterior horn tears in adolescent knees. For smaller tears without substantial displacement, we use these devices alone. For larger tears with displacement, eg, bucket-handle tears, we use them in a hybrid manner with inside-out sutures (Fig. 5) . Regardless of instrumentation used, surgical principles are important to maximize meniscal healing and include preparation of the repair site using abrasion or trephination, anatomic reduction of the meniscal tear, adequate strength and durability of repair devices, and protected knee mobilization.
A Cochrane library review evaluated &quot;the effects of common surgical interventions in the treatment of meniscal injuries of the knee. The four comparisons under test were: a) surgery versus conservative treatment, b) partial versus total meniscectomy, c) excision versus repair of meniscal tears, d) surgical access, in particular arthroscopic versus open.
Three trials, involving 260 patients, which addressed two (partial versus total meniscectomy; surgical access) comparisons were included. Partial meniscectomy may allow a slightly enhanced recovery rate as well as a potentially improved overall functional outcome including better knee stability in the long term. It is probably associated with a shorter operating time with no apparent difference in early complications or re-operation between partial and total meniscectomy. The long-term advantage of partial meniscectomy indicated by the absence of symptoms (symptoms or further operation at six years or over: 14/98 versus 22/94; Peto odds ratio 0.55, 95% confidence interval 0.27 to 1.14) or radiographical outcome was not established. The results available from the only trial comparing arthroscopic with open meniscectomy were very limited in terms of patient numbers and length of follow-up. However it is likely that partial meniscectomy via arthroscopy is associated with shorter operating times and a quicker recovery.
Reviewers&apos; conclusions: The lack of randomised trials means that no conclusions can be drawn on the issue of surgical versus non-surgical treatment of meniscal injuries, nor meniscal tear repair versus excision. In randomised trials so far reported, there is no evidence of difference in radiological or long term clinical outcomes between arthroscopic and open meniscal surgery, or between total and partial meniscectomy. Partial meniscectomy seems preferable to the total removal of the meniscus in terms of recovery and overall functional outcome in the short term.&quot; (1)