Knee Rotary Instability: Difference between revisions
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== Epidemiology/Etiology == | == Epidemiology/Etiology == | ||
*ACL reconstruction causes a persistent pivot shift in over 15% of<br>cases. Main cause of graft failure is the presence of unrecognized, and therefore untreated, PLRI.<ref name="Tiamklang">Tiamklang T, Sumanont S, Foocharoen T, Laopaiboon M. Double-bundle versus single-bundle reconstruction for anterior cruciate ligament rupture in adults. Cochrane Database of Systematic Reviews 2010, Issue 3. Art. No.: CD008413. DOI: 10.1002/14651858. CD008413.</ref> | |||
*Diagnosing PLRI is difficult because it occurs rarely and is slow to develop. In our series, PLRI was not recognized in 34 (50%) patients at the initial diagnosis. <ref name="Goo Kim" /><br><br> | |||
== Characteristics/Clinical Presentation == | == Characteristics/Clinical Presentation == | ||
Revision as of 19:57, 15 July 2011
Original Editors
Lead Editors - Mary Harris, Shannon Davis, Misty Hillin, Bryan Purkey, Bryan Jacobson
Search Strategy[edit | edit source]
add text here related to databases searched, keywords, and search timeline
Bryan J
Definition/Description
[edit | edit source]
Excessive external rotation of the tibia relative to the femur resulting in a varus thrust during normal gait. A rotary instability often occurs with concomitant ligamentous injuries making it difficult to detect/diagnose. [1]
Epidemiology/Etiology[edit | edit source]
- ACL reconstruction causes a persistent pivot shift in over 15% of
cases. Main cause of graft failure is the presence of unrecognized, and therefore untreated, PLRI.[2] - Diagnosing PLRI is difficult because it occurs rarely and is slow to develop. In our series, PLRI was not recognized in 34 (50%) patients at the initial diagnosis. [1]
Characteristics/Clinical Presentation[edit | edit source]
Purkey
Differential Diagnosis[edit | edit source]
Damage to:
ACL
PCL
MCL
LCL
Posteriolateral Corner
Avulsion Fracture
Or any combination of the above.
Relevant Anatomy[edit | edit source]
The Posteriolateral compartment (PLC) can be described as consisting of 5 structures (2 muscles and 3 ligaments); the lateral head of the gastrocnemius, the popliteus, the popliteofibular ligament, the lateral collateral ligament (LCL), and the arcuate ligament–fabellofibular ligament complex. The biceps femoris tendon and iliotibial band also contribute to the stability of the PLC of the knee, and may be damaged with injuries in this region. The PLC serves as the primary restraint to both varus and external rotation forces, with the PCL acting as a secondary restraint. The LCL plays the greatest role in resisting varus stress, while the other components of the PLC play a larger role in resisting external rotation of the lateral side of the tibia on the femur. The popliteus and popliteofibular ligament, in particular, have been shown to be the most important structures in resisting external rotation.[3] Disruption of the PLC with an intact PCL results in increased varus and external rotation of the knee, most pronounced at 30° of knee flexion, while disruption of the PCL with an intact PLC results in increased posterior translation of the tibia, most pronounced at 90° of knee flexion. Disruption of both the PLC and PCL causes increased varus angulation, external rotation, and posterior translation at all angles of knee flexion [3].
Examination
[edit | edit source]
PT Examination[1]
Dial Test: 30* knee flexion, Tibial external rotation
- Look for posterior sag, and apply anterior force during test for neutral tibial positioning.
Reverse Pivot Shift Test
- (+) test, knee subluxation in flexion and posterior sag of proximal tibia
- False positive rate- 35%
External Rotation Recurvatum Test
- (+) Test, hyperextension, external rotation of tibia, and tibial varus
Posterolateral Drawer Test
- Significant increase in PL translationin 15* external rotation
Varus Stress Test
(+) Dial test demonstrating Ext Rot, and Lateral tibial subluxation
(+) Posterior drawer test
(+) Varus test
Imaging
Standard radiographs of the knee can show several findings suggestive of acute PLC injury, including abnormal widening of the lateral joint space, fibular tip avulsion fracture or fracture of the fibular head, avulsion fracture off Gerdy’s tubercle in iliotibial band injuries, tibial plateau fracture, or even a Segond fracture. Although Segond fractures typically occur with ACL tears, they also can occur in isolated PLC injuries. Recent studies have shown that either T1- or T2-weighted coronal oblique images through the knee and including the entire fibular head and styloid process provide the best visualization of the individual structures of the PLC. Magnetic resonance imaging will also detect associated injuries, including ACL and PCL tears, fractures, and bone contusions, which typically occur in the medial femoral condyle or medial tibial plateau [3].
Diagnosis[edit | edit source]
Grade 1:
- Tibial external rotation 5-10* difference, without varus instability[4]
Grade 2:
- Increased ER >10* difference, OR posterolateral subluxation of tibial plateau with grade 0-2 varus instability[4]
Grade3:
- Tibial exernal rotation >10* difference /s firm end point, with grade 3 varus instability from LCL injury[4]
Medical Management
[edit | edit source]
Shannon
Physical Therapy Management
[edit | edit source]
Shannon/ Purkey/ Jacobson
Key Research[edit | edit source]
add links and reviews of high quality evidence here (case studies should be added on new pages using the case study template)
Resources
[edit | edit source]
add appropriate resources here
Clinical Bottom Line[edit | edit source]
Group
Recent Related Research (from Pubmed)[edit | edit source]
Bryan J
see tutorial on Adding PubMed Feed
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References[edit | edit source]
see adding references tutorial.
- ↑ 1.0 1.1 1.2 Goo Kim, J et all. Correlation between the rotational degree of the dial test and arthroscopic and physical findings in posterolateral rotatory instability. Knee Surg Sports Traumatol Arthrosc (2010) 18:123–129
- ↑ Tiamklang T, Sumanont S, Foocharoen T, Laopaiboon M. Double-bundle versus single-bundle reconstruction for anterior cruciate ligament rupture in adults. Cochrane Database of Systematic Reviews 2010, Issue 3. Art. No.: CD008413. DOI: 10.1002/14651858. CD008413.
- ↑ 3.0 3.1 3.2 Ricchetti E, Sennett B, Huffman G. Acute and chronic management of posterolateral corner injuries of the knee [corrected] [published erratum appears in ORTHOPEDICS 2008 Jul;31(7):725]. Orthopedics [serial online]. May 2008;31(5):479-490. Available from: CINAHL Plus with Full Text, Ipswich, MA. Accessed July 13, 2011.
- ↑ 4.0 4.1 4.2 Young-Bok J, et al. The Inf uence of Tibial Positioning on the Diagnostic Accuracy of Combined Posterior Cruciate Ligament and Posterolateral Rotatory Instability of the Knee. Clinics in Orthopedic Surgery 2009;1:68-73.
