Ortho Study Guide-Quiz 2
Meniscus Transplantation
 Meniscal Surgical History
 Prior to knowledge of the vital function of the menisci--- they were routinely resected
 This led to predictable development of degenerative changes in the jt
 Subsequently preservation of the menisci tissue has been a main goal of surgery
 An alternative procedure: Mensical Transplantation
 Men. Transplant. Is an alternative for the young pt who has degenerative changes in
the knee 2 prior total menisectomy
 Structure and Function
 Menisci are intracapsular fibrocartilaginous structures
 Structure: Consists of water, collagen, and proteglycans--75% type 1 collagen--- great
tensile strength
 Arranged in a circumferential pattern
o Plays critical role in load transmission. With weight bearing- the load is
transmitted to the menisci causing them to extrude. Circum. Orientation of
the fibers resists this causing the strain to bear as hoop stresses. Disruption
of the fibers leads to loss of this function.
 Functions
 Distributes weigh over
 Provide shock
a large surface
absorption
 Increase jt congruency
 Acts as a solid lubricant
 Shapes and Sizes of the Menisci
 Medial Meniscus- Shaped like a capital C
 Bears 50% of the load in the medial compartment
 Attachments
o Ant. intercondylar area to post. Intercondylar area
o Tibial collateral ligament
o Coronary ligament attachs to tibia
o Transverse ligament
o More securely attached compared to lat. Meniscus
 Lateral Meniscus- shaped like a lowercase o
 Bears 70% of the load in the lateral compartment
 Attachments
o Lateral intercondylar area to lateral intercondylar eminence
o Popliteus tendon attached to post. Horn of meniscus to avoid impingement
o Coronary lig attaches to the tibia
o Transverse ligament
 Meniscus Movements
 During flex-ext: Both menisci move post. Lateral is displaced more than medial
 Menisci prevent the jt capsule from entering the jt

Locking Mechanism of the jt into close packed position. They direct the femoral articular
condyles
 Coronary ligs tend to be looser on the lat. side--- contributes to the inc mobility in the lat
meniscus
 Meniscal Tears
 Can be classified by location or pattern
 Location
 Red-Red: Greatest vascularity and best healing potential
 Red-White: Near the peripheral margin but a suboptimal blood supply
 White-White: Neither side demonstrates vascularity
 Patterns
 Longitudinal- “Bucket Oblique
handle”
 Radial
 Horizontal Cleavage Complex
“Parrot beak”
 Degenerative
 Demographics
 Young athlete- cause of injury by high energy mechanism
 >40 yrs old- degenerative tears with no recollection of trauma
 Signs and Symptoms
 Tears may or may not be symptomatic
 Symptoms include:
 Clicking and pain with
 Giving way
activity
 Positive Diagnostic and
 VMO atrophy
Specials tests
o McMurray,
 Pain with or without
Apleys,
swelling
Andersons
 Locking and Unlocking
Med-Lat Grind
 Jt line tenderness
 Blocking at end ranges
 Indications for Transplantation
 Young pt (<50) symptomatic after menisectomy (not age appropriate for total knee)
 Concomitant procedure to ACL reconstruction in medial meniscus deficient knee
 Prior total menisectomy with articular cartilage degeneration and pain
 2mm or more of tibiofemoral jt space on 45 weight bearing posteroanterior radiograph is
necessary for tx
 Contraindications of Transplantation
 Malalignment
 Concavity of Tibial Plateau
 Varus or Valgus deformities
 Osteophytes
 Foal chondral defects
 Obesity
 Ligament Instability
 RA
 Advanced arthritis
 Infection
 Femoral flattening

Lack of commitment to
 Muscular Atrophy
postoperative restrictions
 Rehabilitation Program
 Goal: To prevent excessive weight-bearing forces
 Control high compressive and shear forces
 Immediately post-op
 Pt placed in hinged long-leg brace for 6 wks
o In 0 to 90 flex during rehab
o Locked in full ext for 4 wks unless otherwise indicated
 Patellar mobs in all directions
 PROM, AROM
 Stretching of hams, gastroc
 Quad re-education
 Cryotherapy 6-8 x a day 15-20 mins
 Pt is placed on crutches
o First 4 wks TTWB, FWB by 6 wks
 Weeks 0-6
 By week 6 FWB. ROM 90 -135
 Hamstring curls, knee ext, hip add/abd, weight shifting
 Progressively add exercises every 2 wks.
 Weeks 6-14
 Should have full ROM by week 8-14
 Quad and IT band flexibility exercises added
 Weight bearing exercises begin
 Cardiovascular
o Stationary bike, Walking in water, Swimming and walking on land (9th week)
 Weeks 14-22
 Resistance Exercises are added
 Cardiovascular: stair climbing machine
 Week 20-30
 Squat to 90
 Running is permitted. Progress to crossover maneuvers
 Outcome Measurements
 Testing effectiveness,
 Palpation
functioning, and integrity of
 Special Tests
mensical transplant
 Imaging
 Subjective Assessments
 Histologic Analysis
 ROM
 Arthroscopy
 Main Reasons for Transplant Failure
 Coexisting Degenerative Disease
 Limb Malalignment: places uneven pressure on the involved compartment
 Procedure to prevent this: combined osteotomy-mensicus transplant
 Summary
 Meniscus is critical to knee stability, mobility, and integrity
 If compromised jt degeneration is inevitable, and due to poor vascularization
surgery is often indicated
 Transplantation is an effective alternative for the young pop. with a h/o menisectomy
 Surgical techniques: Double Bone Plug & Single Bone Bridge
 Rehab is similar to repair but with slower progression of activity
 Studies have shown that pt have pain relief and inc function and meniscal transplants have
survival of nearly 75% at 10 years. Beyond 10 yrs is inconclusive
 Even after appropriate surgery and rehab pts will not be able to return to high level
athletics.
Magnetic Bone Stimulators for Fusion of Persistent Non-Unions
 Externally applied flexible therapeutic magnets
 Magnetic field too small to influence tissue
 Do not influence healing speed
 Do not influence tissue temperature
 Bone Stimulator- Produces a magnetic field capable of influencing tissue growth. Can be internal
or external.
 Increased healing percentages esp. when at high risk for non-union
 Bone stimulators do NOT increase the speed of healing
 Prophylaxis of non-union
 1). Causes of non-union
 Improper position/pseudoarthrosis
 Improper or insufficient immobilization
 Infection
 Presence of soft tissue interposed btw the edges of fractured bone
 Inadequate blood supply
 Poor nutritional status
 Metabolic bone disease
 Specific pathology
 Factors determining high risk for non-union
 Tobacco use
 Anti-inflammatory
drugs
 Older age
 Steroids
 Severe anemia
 Infection
 Diabetes
 Poor vascular supply
 Types
 1). Surgically Implanted Electrodes
 2). Externally Fixated Electromagnetic Amplifiers
 Direct Current
 Pulsed Electromagnetic Field (PEMF)




 Extracorporeal Shock Wave Therapy (ESWT)
 Interference Current (IFC)
 Diathermy
History of Bone Stimulators:
 Surgically Implanted Devices
 Magnets
 Infection Risk
 Implanted Electrodes
 Removal Surgery
 E-Stim across fracture site
 Open Castings
How do Bone Stimulators Work?
 Bone growth effected by 3 physical strategies:
 Mechanical Stimulation
 Low intensity ultrasound (studies have conflicting results, quality of evidence is
questionable, and use in clinical practice is unsupported)
 Electromagnetic fields
Biochemistry Involved:
 Wolff’s Law: Bone growth effected by stressors
 Increased stress -> Osteoblastic activity-> Increased cortical thickness
 Decreased stress-> Osteoclastic activity
 NWB status inhibits bone growth
 Research proves bone is Piezoelectric: Charge separation produced by stress
 Tension causes a + charge formation :Osteoclastic activity
 Compression causes a – charge formation: Osteoblastic activity
 Electromagnetic fields can influence polarity/membrane potentials
 Hall effect- electromotive force that causes charged particles to accumulate with like
charges in the presence of a magnetic field
 Resisting the motion of charged particles in the bloodstream by magnetic polar
inductance induces friction which causes a thermal effect
 Increase in temperature causes vasodialation
 Magneto hydrodynamic effect- Increased delivery of molecular oxygen for cellular
metabolism and reduction of secondary tissue hypoxia.
Bone Stimulator Biochemistry:
 Hypothesized mechanism:
 Increase Osteocyte
 Increase O2 exchange
activity
 Focal Application
 Increase blood flow
 Electromagnetic fields:
 alter the effects of hormones on the cell membranes
 increase production of growth factors and receptors
 affect calcium flux across membranes
 stimulate endothelial cell proliferation and capillary formation
 Electromagnetic fields
 Any flow of electric current produces an electric field
 Types of electric current
 Direct current
 IFC
 Alternating current
 ESWT
 PEMF
 Most are too small to effect bone growth
 Bone stimulators are basically amplified magnetic fields
 1.) Direct Current
 Cathode is place percutaneously at fx site and anode is placed on the skin
 Immobilization and NWB status is prolonged and therefore a drawback
 Constant direct current is applied for 12 weeks
o Direct current study concluded that bone stimulators may be very
effective in achieving union in fractures that have persistent infection
(86%)
 2.) Interference Current Uses capacitive coupling stimulators
 Interference currents are pulsed using surface electrodes
o Interference current study showed that electrical capacitive coupling is
notably effective in achieving union in fxs that have previously not
healed. It also shows the versatility of the treatment (different sites were
used)
 Extracorporeal Shock Wave Therapy (ESWT)
 Non-Invasive procedure using high energy shockwaves for healing non union fractures
 Shockwave energy is carefully positioned in the plane of the fracture and the total
energy from different directions is divided into equal parts ranging from 2-24 directions
 ESWT study showed 75.7% successful healing rate
 Pulsed Electromagnetic Field (PEMF)
 Non-Invasive e-stim
 Inductive Coupling stimulator is a unit that produces a pulsed field which is fixed to a
plaster cast and can be plugged into a standard home outlet
 Tx is 10 hours daily for 12 weeks while pt. remains NWB
 A report from 1981 showed PEMF had an 87% success rate healing 127 cases of
non union tibial fxs
 Another study looked at PEMF for congenital pseudarthrosis of the tibia and
showed favorable results for type I and type II non-unions
 A meta analysis suggested that current evidence is insufficient to conclude a
benefit of EMS in improving the union in fresh fx, osteotomy, delayed union, or
non union. Also not sufficient to conclude decreased time to healing in tibial fxs,
or reducing pain in these patients.
 *Another study looked at effectiveness of strong magnetic field bone stimulators
and showed that SMF has the potency to stimulate bone formation and regulate
its orientation.
 Bone stimulators and insurance coverage
 Some insurance companies mandate bone stimulation as a standard of care in order to
qualify for reimbursement. Conditions requiring this include the following:
 Previous non-unioned
 current smoking habit
fx
 diabetes
 grade III or worse
 renal disease
spondylolisthesis
 alcoholism
 fusion performed at
more than one level
 Synthesis
 Electromagnetic fields are an appropriate and effective treatment for persistent non union
fractures
 Can be used with or without bone grafts as long as the fx site is immobilized
 Research showed a range of healing times, but regardless healing was complete
 There was inconsistency between the meta analysis and previously published research
(perhaps due to extensive inclusion criteria for meta analysis)
 PT Conclusion: PT may be responsible for:
 Instruction for use / HEP
 Adherence
 Ordering info
 Documentation/Insurance
 D/C planning
Microfracture Surgery of the Knee
 What is microfracture surgery?
 Surgical reparative technique that induces healing to occur in area of articular cartilage
damage
 MFS of subchondral bone is a bone marrow stimulation technique for the tcx of chondral
defects
 Can be performed on a variety of jts
 Articular Cartilage
 Composed of water, cells, matrix—contains type 2 collagen fibers
 Helps in distributing loads across the knee jt
 Reduces stress on subchondral bone and minimizes friction
 Avascular and Aneural- therefore if left untreated have little or no potential to heal
spontaneously
 Areas of MFS (Knee)
 Medial femoral condyle
 Trochlea
 Lateral femoral condyle
 Patella
 Tibial plateau
 Combo of any above
 Candidates for Microfracture
 Athletes
 Pts who present with unilateral or bilateral knee pain
 Elderly arthritic pts who are still active
 Goals of MFS
 Alleviate pain
 Maximize function
 Indications
 Focal traumatic chondral
defects
 Degenerative lesions
 Unipolar or Bipolar lesions
 Defects size <4 cm
 Cartilage lesions

Delay degenerative changes

Focal grade 3 or 4 articular
surface lesions without bone
loss that are surrounded by
normal cartilage
Relatively short pre-op
duration of symptoms
Optimal pt age <45


 Relative Contrindications
 Significant subchondral bone
loss
 Mechanical axis malalignment
of the knee
 Bipolar lesions





High risk of noncompliance
with post-op rehab
Defect size > 4cm
BMI >30
Mensical deficiency
Pt age >60
 Absolute Contraindications
 Generalized degenerative jt
 High grade lig instability
changes
 Tumor
 Limited pt compliance
 Infection
 Uncontained chondral lesions
 Inflammatory arthropathy
 Systemic cartilage disorders
 Severe axial malalignment >5 
 Patellar mal-tracking or
instability for pf lesions
 Risks for Microfracture
 Bleeding & Infection
 Inc Stiffness & Cartilage Breakdown
 Why MFS?
 Does not burn any bridges with regard to future surgical procedures
 Allows for perforations to still be created while eliminating risk for thermal necrosis
 Surgeon is able to better assess areas of articular surface
 Disadvantages of MFS
 Tissue is composed of type 1 collagen rich fibrocartilage which does not resist compression
and shear loads
 Post Op Rehab
 IMPORTANT
 Depends on the location of the chondral defect
 NWB 4-6 weeks to allow cartilage to heal
 Use of CPM machine to prevent arthofibrosis and allows the defect to heal properly
 Conclusions
 Demonstrated effective for
 Some athletes
 Individuals <40
 Individuals with
osteonecrotic knees
 Demonstrated uneffective for
 Individuals >40
 Chondral defects > 2cm


Animals
Femoral condyles

Some Athletes
The Anterior Cruciate Ligament
 Acts as the primary restraint to anterior tibial translation and guides the screw home mechanism associated
with TKE.
 One of the most commonly injured ligaments in the knee; predominantly in young athletes
 After injury, the chance of meniscal injury and osteoarthritis rises sharply
 ACL Stats:
 Occurs in about 1 of 3000 ppl
 Over 100,000 injuries occur from skiing per year in the USA
 Cost management is approx 2 billion annually
 Females at higher risk, possibly due to:



Larger Q-angle

Different cutting and
landing patterns


Less strength
Increased joint laxity
Uneven muscle activation
Hormonal Differences
 70% of injuries are from a non contact mechanism such as stopping, cutting, or side stepping
 Relevant Anatomy
 Ligament is intrarticular but extrasynovial
 Composed of 3 main bundles: anteromedial, posterolateral, & intermediate
 Ligament runs obliquely from tibia anteriorly and medially to the femur posteriorly and laterally
 Composed of collagen fiber and elastin
 Blood supply from middle geniculate artery
 Anatomy of the Knee





 Indications for Surgery
 Recurrent effusions and instability
 Associated meniscal injury
 Patient is involved in more than 50 hours of high level activity annually
 Patients with translation greater than 7mm
 Contraindications for Surgery
 Infection
 Low activity levels
 Soft-tissue abrasion
 Osteoporosis
 Pt. reluctant to participate in
 Skeletal Immaturity
rehabilitation
 Inflammatory arthropathy
 Less than 2 weeks from injury
Postoperative ACL
 Up to 170% strength of original ACL
 Around 4 weeks, 10% strength of original ACL
 Cellular repopulation and revascularization can take upto 24 weeks. Reorganization can take upto 32
weeks
 Postoperative collagen cannot withstand tensile stress
 Cyclic loading can positively impact the remodeling process by helping fibers realign. This increases
knee stability and improves kinematics
Knee Bracing Postoperatively
 Provides mechanical stress protection of the graft
 Permits motion through modified arcs
 May protect graft from low level cyclic stress
 May assist kinematic guidance of the remodeling graft
 May increase proprioception to the lower extremity
 Inhibits anterior translation through level
Psychological Aspects
 Most widespread + effects are from anecdotal evidence
 Pt’s report increased sense of security and stability and a sense of improved functional performance
 Pt’s have desire to rehab faster and more aggressively
 Be aware of the above and follow precautions of the repair
 Proprioceptive benefits may only be due to cutaneous contact
Cadaver Studies
 Allows direct measure of ligament strain in anatomical range
 Advantage- Lack the tension of living soft tissues , therefore effects in vivo may be more effective
 Disadvantage- The axial tissues of the limb do not respond to the contact of the knee brace
Studies
 short term post op bracing is beneficial to the patient’s sense of recovery and confidence, however a
lengthened use could lead to adverse effects
 that there are no detrimental effects of post op knee bracing, however, after 3 months,
counterproductive results were observed. Also, patient specific brace selection should be used
considering: principal role of the brace, nature of the instability, specific morphologic or physiologic
requirements, neurovascular conditions, or patient goals.
 Controversial Issues
 Custom vs. Off the shelf
 One study showed no difference in efficacy
 Restriction vs. no restriction of rotation of the knee
 Effect on proprioception
 Bracing Trends Amongst Physicians (survey was completed)
 Bracing among MD’s has been less frequent
 With ACL deficient patients, 35% of doctors brace 20% of the time
 With ACL reconstructed patients, 31% of doctors brace 81-100% of the time
 MD’s base brace rx on amount of activity of the pt.
 Most prescribed brace is Don Joy
 When are functional braces used?
 With discovery of ACL deficiency of following trauma
 Used for general stabilization and to prevent anterior forces of the tibia on the femur
 Most studies done look at effects braces have on proprioception, muscle dynamic stability, and tibial
translation
 Proprioception
 Mechanoreceptors have been found specifically in the ACL that assist in knee proprioception
 Therefore, it is speculated that with ACL injury, proprioception is effected
 Compare both sides by testing threshold of passive knee motion?
 Study found that threshold of passive knee motion was impaired
 Study also showed that brace did not improve the threshold
 Dynamic Stability
 Strengthen hamstrings, quads, and gastroc to prevent anterior translation
 Hamstrings are esp imp to prevent ant. translation during gait
 Study shows that braces decrease muscle performance but increase stability
 Another study shows that brace dependency may be detrimental to hamstring strength.
 Symptoms of the chronic ACL deficient knee
 Discomfort
 Giving out
 Swelling
 Radiograph abnormalities
 Weakness
 Changes in muscle recruitment time
 Rule of 3 for ACL injuries
 1/3 will compensate adequately and be able to participate in recreational activities
 1/3 will be able to compensate but will have to give up significant activities
 1/3 will do poorly and prolly require reconstructive therapy
 Non operative management
 E-stim with leg curls and leg press
 unopposed practice of sport specific
skills
 Treadmill running, stationary cycling,
sliding board training
 opposed practice
 half-speed agility skill training
 full with team
 Non operative summary
 Limited success for those participating in high level physical activity
 23%-39% success rate for returning patients back to high levels of activity