*With the exception of programs from the ACCEL series, each of which qualifies for up to 4 Category 1 CME credits.
Volume 36, Issue 12
June 21, 2013
Knee Dislocations: Acute Care and Reconstructive Options Charles A. Bush-Joseph, MD
Current Concepts in Meniscus Injuries Mark R. Hutchinson, MD
Patellofemoral Instability Jason L. Koh, MD
The Difficult Knee Arthroplasty David Manning, MD
Reconstruction of the Anterior Cruciate Ligament in Children Drew E. Warnick, MD
The following is an abstracted summary, not a verbatim transcript, of the lectures/discussions on this audio program.
Orthopaedics Program Info Accreditation InfoCultural & Linguistic Competency Resources
A Nod to the Knee
The goals of this program are to improve management of knee dislocations, meniscal injuries, patellar instability, difficult knee arthroplasty, and pediatric anterior cruciate ligament (ACL) reconstruction. After hearing and assimilating this program, the clinician will be better able to:
1. Implement treatment strategies for knee dislocations.
2. Recognize and consider signs and symptoms, relevant anatomy, use of imaging, and treatments related to meniscal injuries.
3. Discuss relevant anatomy and surgical techniques for patellofemoral instability.
4. Use the methodical approach for the difficult primary knee arthroplasty.
5. Describe treatment options for pediatric ACL reconstruction.
In adherence to ACCME Standards for Commercial Support, Audio-Digest requires all faculty and members of the planning committee to disclose relevant financial relationships within the past 12 months that might create any personal conflicts of interest. Any identified conflicts were resolved to ensure that this educational activity promotes quality in health care and not a proprietary business or commercial interest. For this program, the faculty and planning committee reported nothing to disclose.
Knee Dislocations: Acute Care and
Charles A. Bush-Joseph, MD, Professor of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL
Background: 25% of knee dislocations present with injury to popliteal artery or peroneal nerve; ≈50% of nerve injuries lead to permanent deficits
Anatomy: cruciate ligaments attach to intercondylar eminence; posterior knee — place finger into posterior cruciate ligament fossa with open approach or direct visualization; medial knee — superficial medial collateral ligament (MCL) stretches from medial epicondyle to 7 to 10 cm distally; lateral knee — lateral collateral ligament (LCL) comes off posterior aspect of lateral epicondyle and down to anterior aspect of fibula; popliteal fibular ligament (represents ligamentous portion of popliteal tendon that attaches to posterolateral margin of tibia and fibula) resists external rotation and spin
Evaluation: classification of knee dislocations I to IV based on number and pattern of ligaments damaged; high velocity injuries — have worse prognosis; associated with higher degrees of soft tissue injury, muscle and capsular damage, other organ injuries, and neurovascular injury; low velocity injuries — have better outcome; associated with isolated ligamentous damage, lesser degree of muscle damage, easier repair, less soft tissue stripping, and less meniscal and articular damage
Examination: locate popliteal artery (often tethered at adductor hiatus and soleus arch distally); observe patients with ankle brachial index (ABI) >0.9; perform imaging on patient with ABI <0.9; perform serial examinations with ABI because intimal tearing can present in delayed fashion; vascular injury requires definitive treatment within 6 to 8 hr; perform prophylactic fasciotomy; physical examination (PE) alone insufficient to diagnose vascular injury; PE — verify whether extensor mechanism intact; perform stabilized Lachman test under anesthesia; instability in extension suggests bicruciate injury and significant capsular injury; anterior medial dimpling suggests unreduced anteromedial dislocation; residual posterolateral sag indicative of locked posterolateral dislocation; PE only 55% to 80% accurate; order magnetic resonance imaging (MRI); initial radiographs indicate direction of dislocation; reduce knee before MRI
Surgery: perform open reduction and place external fixator (ex fix) for irreversible posterolateral dislocation; wait on polytrauma patients; wait 7 to 14 days for isolated injury to allow improvements in skin, swelling, pain control, and muscle activation; before surgery — mobilize patient; perform vascular rechecks; provide deep venous thrombosis prophylaxis; achieve muscle activation
Lateral side injury: early aggressive approach; wait 10 to 14 days after injury; easier dissection increases chance for primary repair of capsule and collateral ligaments; augment repair with semitendinosus or allograft tissue
Medial side injury: place in long leg hinged knee brace or ex fix for 6 to 8 wk; reassess collateral stability; fix cruciate injuries; degree of posterior capsular injury determines earlier approach; operate earlier (1-3 wk) for distal MCL injury
Surgical technique: place ex fix for grossly unstable knee or polytrauma patients; use anterior approach and place knee in 10° to 15° flexion; immobilize 4 to 6 wk; gradually restore motion; delay treatment of other problems; diagnostic arthroscopy — assess intra-articular pathology; look for “drive through” sign on lateral side; perform in single setting or staged approach; perform with open techniques and wide skin bridges; exercise care with capsular repair; high risk for heterotopic ossification on medial side; speaker uses allografts instead of autografts
Current Concepts in Meniscus Injuries
Mark R. Hutchinson, MD, Professor of Orthopaedics and Sports Medicine, University of Illinois, Chicago
Meniscal injury: symptoms — popping, snapping, clicking, acute hemarthrosis, and “giving way” sensation; PE — joint line tenderness most common finding; McMurray test most specific; 90% positive when loading meniscus results in feeling click and pop associated with pain
Meniscal anatomy: composed of circumferential fibers; anterior and posterior roots must be attached or meniscal repair fails; loss of meniscus results in 3-fold higher focal stress on tibia (leads to arthritis); consider meniscal repair for tears in vascular zone (peripheral third)
Imaging: trust clinical findings; consider MRI for equivocal examination; watch for false positives on MRI (ie, type I or II intrasubstance degenerative meniscal tear); true tears communicate with inferior surface; false positive findings include intermeniscal ligament, popliteus tendon (posterolaterally), and lateral inferior geniculate artery; order MRI for unclear examinations, preoperative planning, multiligament or complex injuries, elite athletes, and workers’ compensation cases
Treatment: repair any potentially repairable meniscus to reduce risk for arthritis; vertical mattress sutures grab circumferential fibers; pass sutures divergently across meniscal surface to re-approximate repair surface for broader contact area for healing; avoid dependence upon one technique; learn inside-out, outside-in, and all-inside repairs; protect saphenous nerve medially; pass needles and sutures with knee extended for medial repair to avoid grabbing posterior capsule; look for peroneal nerve laterally
Meniscal transplant: indicated for absent meniscus and correctable comorbidities with intact cartilage; keep bone plug; attach transplanted tissue at roots anteriorly and posteriorly; satisfaction 86% with fresh frozen grafts; 5-yr survival 80%; results good even with complex injuries
Conditions: meniscus root avulsion — commonly missed; repair when possible; discoid meniscus — occurs in 1% to 5% of population; more common within Asian population; more common laterally (20% bilateral); look at posterior anchor to avoid missing root injury; Wrisberg variant has no posterior meniscal attachment; repair posterolaterally with anchors; results good to excellent in 80% to 85% for debridement and saucerization when peripheral aspect attached
Jason L. Koh, MD, Clinical Associate Professor, University of Chicago Pritzker School of Medicine, Chicago, IL; Chairman of Orthopaedic Surgery, NorthShore University Health System, Evanston, IL
Anatomy: factors affecting stability — bony anatomy, eg, trochlear shape and tibial trochlear groove alignment; soft tissues, eg, medial patellofemoral ligament (MPFL; comprises 50%-60% of stabilizing forces for patella), lateral retinaculum (provides ≈22% of stabilizing force for patella); vastus medialis obliquus (VMO); leg positioning for dynamic stability; patellar motion — trochlea captures patella at ≈20° of flexion; instability occurs before capture; MPFL — provides primary soft tissue restraint; extends from medial patella to medial part of femur; located in second layer (confluent with undersurface of VMO); provides 208 N force; tearing can occur anywhere along MPFL; tightest in extension and loosens with flexion; recreate anatomy with reconstruction or repair; MPFL length can vary ≤11 mm with knee extension and flexion
Patellar dislocation: natural history — 17% to >50% recurrence rate for first-time dislocation; Cofield and Bryan (1977) reported poor function in 60% of patients with history of dislocation and recurrent symptoms in 30% to 50%; nonoperative management for first dislocation involves lateral buttress brace and physical therapy (for hip external rotation and VMO strengthening; results variable)
Surgery: indications — presence of loose body, significant articular cartilage lesion, or high-risk patient who desires stability after first dislocation; options — plication for minor stabilization; MPFL reconstruction or repair for instability with normal alignment; add tuberosity transfer for abnormal bony alignment; preoperative imaging — order MRI to look for damage to MPFL; measure distance of tibial tubercle to trochlear groove from axial MRI or computed tomography (normal distance ≈10 mm); assess articular cartilage and patellar height
Surgical techniques: lateral release — International Patellofemoral Study Group does not recommend isolated lateral release for patellar instability; medial plication or MPFL repair — good option for mild laxity or capsular stretch and little bony malalignment; tension medial lateral rather than superior inferior
Medial plication: perform along MPFL; Halbrecht (2001) described all-arthroscopic repair; other studies describe repair at adductor tubercle; consider reconstruction over repair for additional strength
MPFL reconstruction: perform for recurrent instability without severe bony abnormality; graft must be loose in knee flexion; tightness in flexion overstretches graft or overloads patella
The Difficult Knee Arthroplasty
David Manning, MD, Associate Professor of Orthopaedic Surgery, Northwestern University Feinberg School of Medicine, Chicago
Background: surgical success depends on proper implant orientation and soft tissue management; proper mechanical alignment (ie, 5° valgus) optimizes mechanical nature of implant materials; manage gap balancing; look at posterior femoral condylar offset; posterior capsule acts as secondary restraint against sagittal instability; properly size posterior condyles
Implant orientation: new technology involves patient-specific instrumentation; tibial alignment — rely on crest; tibia usually s- or c-shaped; reliance on middle-third of tibia for alignment in coronal plane may introduce error; femoral alignment — use Whitesides line (perpendicular to epicondylar axis); avoid instruments with paddles on posterior femoral condyles; perform secondary anatomic checks throughout procedure; look for anterior “piano sign” and asymmetric posterior femoral epicondylar cuts; look for symmetric flexion gap at 90°; look for femoral lift-off; assess patellar tracking; proper tibial placement depends on size, tibial coverage, and rotation; ideal implant lies out on cortex to help prevent subsidence; tibial rotation cannot outcompete poor femoral rotation; use middle third of tibial tubercle as landmark; postoperative PE — good range of motion (ROM) with congruent bearing; no varus valgus shuck at full extension (desire ≤5 mm of shuck at 90°); proper patellar tracking
Challenges: anticipate stiffness (optimize ROM with extra soft tissue releases and re-establish gutters); determine magnitude and etiology of malalignment; re-establish joint line; manage ligamentous instability after releases and bone loss; evaluate extensor mechanism; optimize fixation
Joint line restoration: use medial epicondyle as landmark; patients with poor joint line restoration exhibit mid-flexion instability with effusions, instability with bearing weight in mild flexion, and extensor mechanism overload; present with anterior knee pain, recurrent effusions, and stiffness postoperatively
Bone loss: manage like revision cases; restore posterior femoral condylar offset to tension posterior capsule and obtain sagittal stability; MCL-deficient patient requires constraint; low-demand patient without MCL and LCL does not require additional constraint; use hinge knee in patients without extensor mechanism or those with severe flexion extension gap mismanagement
Conclusion: use methodical approach; assess alignment and determine etiology (bone loss or ligamentous); assess soft tissues and ROM; evaluate extensor mechanism and need for joint line restoration; select appropriate implant
Reconstruction of the Anterior Cruciate Ligament
Drew E. Warnick, MD, Affiliate Assistant Professor, University of South Florida, and Surgical Director, Children’s Orthopaedics and Scoliosis Surgery Associates, LLP, St. Petersburg
Extra-articular reconstruction: modified MacIntosh technique wraps iliotibial band (ITB) around LCL or drills tunnel through lateral condyle; advantages include some control of rotation and physeal sparing; disadvantages include minimal control of translation and instability
Physeal sparing nonanatomic procedures: technique 1 — leave gracilis and semitendinosus tendons attached at pes anserinus; transfer tendons underneath intermeniscal ligament and over top with metaphyseal fixation; technique 2 — ITB technique; keeps options open for future; provides good translational and rotational stability; revision easy; may overconstrain
Physeal sparing anatomic procedure: Anderson technique; drill from outside through femoral condyle; all-epiphyseal reconstruction; use metaphyseal fixation on tibia; offers better translational and rotational stability; acute femoral angle may lead to osteolysis; revision difficult; consider modified inside-out technique as alternative
Partial transphyseal procedures: nonanatomic — drill through tibial growth plate; assume over-top position on femoral side; looks similar to popliteus reconstruction; few advantages (provides little translational and rotational stability); risk for physeal injury; anatomic — drill through tibial side; use interference screw and metaphyseal fixation away from growth plate; drill inside out or outside in on femoral side; provides good rotational and translational stability; acute femoral angle; revision difficult; risk for physeal injury
Transphyseal procedures: nonanatomic — uses transphyseal techniques with metaphyseal fixation; vertical drilling removes small hole from growth plate; fill with soft tissue graft; revision easy; provides translational stability but less rotational stability; risk for physeal injury; anatomic — revision easy; acute femoral angle; removal of too much growth plate creates valgus deformity
Treatment algorithm: use bone age; perform ITB procedure or all-epiphyseal reconstruction for young children; perform partial transphyseal anatomic procedure for older children; perform transphyseal anatomic procedures for nearly-skeletally mature children
Dr. Bush-Joseph spoke at the 14th Annual Chicago Trauma Symposium, sponsored by Advocate Health Care and held August 2-5, 2012. Drs. Hutchinson, Koh, Manning, and Warnick were recorded at the 100th Anniversary Meeting of the Clinical Orthopaedic Society, held September 13-15, 2012, in Chicago, IL. For more on the next Chicago Trauma Symposium, please go to www.chicagotraumasymposium.com. For more on the next meeting of the Clinical Orthopaedic Society, please visit www.cosociety.org. The Audio-Digest Foundation thanks the speakers and the sponsors for their cooperation in the production of this program.
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