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Technique guide are not considered high yield topics for orthopaedic standardized exams including the ABOS, EBOT and RC.
Which of the following structures attaches between the medial epicondyle and adductor tubercle of the femur?
Medial head of gastrocnemius
Medial collateral ligament
Medial patellofemoral ligament
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The femoral attachment of the medial patellofemoral ligament (MPFL) is located between the femoral medial epicondyle and the adductor tubercle.
During lateral patellar dislocation, the femoral attachment of the MPFL is a common site of injury and avulsion. Traumatic injury or laxity to the MPFL can cause future patellar instability, as the MPFL is the primary restraint to lateral patellar translation in the first 20 degrees of knee flexion. Surgery for reconstruction of the MPFL requires an understanding of the anatomic landmarks for drilling the femoral socket.
Wijdick et al. used radiopaque markers implanted into the femoral and tibial attachments of the superficial medial collateral ligament and the femoral attachments of the posterior oblique and medial patellofemoral ligaments of cadaveric knees. On the AP radiographs, the attachment site of the MPFL was an average of 42.3 mm from the femoral joint line. On the lateral radiograph, the MPFL was an average of 8.9 mm from the adductor tubercle and was located in the anteroproximal quadrant.
Schottle et al. in a cadaveric study looked at radiographic landmarks for femoral tunnel placement in MPFL reconstruction. A reproducible anatomical and radiographic point, 1 mm anterior to the posterior cortex extension line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to the level of the posterior point of the Blumensaat line on a lateral radiograph with both posterior condyles projected in the same plane, represented the mean femoral MPFL isometric center.
Illustration A shows a cadaveric dissection of the MPFL femoral attachment between the medial epicondyle and adductor tubercle. Illustration B shows a radiographic example of the MPFL femoral attachment between the medial epicondyle and the adductor tubercle. Illustration C shows Schottle's point which can be reliably found radiographically just anterior to the posterior femoral cortex, and proximal to Blumensaat's line on a lateral radiograph.
Answer 1- Medial head of gastrocnemius originates off posterior aspect of medial femoral condyle.
Answer 2- MCL attaches approximately 3.2 mm proximal and 4.8 mm posterior from the medial femoral epicondyle.
Answer 3- Semimembranosus inserts onto posterior surface of the medial tibial condyle.
Answer 4- Adductor magnus inserts onto adductor tubercle.
Wijdicks CA, Griffith CJ, LaPrade RF, Johansen S, Sunderland A, Arendt EA, Engebretsen L
J Bone Joint Surg Am. 2009 Mar;91(3):521-9. PMID: 19255211 (Link to Abstract)
Wijdicks, JBJS 2009
Schottle PB, Schmeling A, Rosenstiel N, Weiler A
Am J Sports Med. 2007 May;35(5):801-4. PMID: 17267773 (Link to Abstract)
Schottle, AJSM 2007
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Which of the following best describes the radiographic landmarks on a lateral radiograph for locating the femoral attachment of the medial patellofemoral ligament (MPFL) during reconstruction?
The intersection of a line extended from the middle of the shaft and Blumensaat's line
Anterior to a line extended from the middle of the shaft and Blumensaat's line
Posterior to a line extended from the posterior cortex of the shaft and distal to Blumensaat's line
Anterior to a line extended from the posterior cortex of the shaft and distal to Blumensaat's line
Anterior to a line extended from the posterior cortex of the shaft and proximal to Blumensaat's line
Correct positioning of a graft for MPFL reconstruction requires accurate placement of the femoral attachment site which is anterior to a line extended from the posterior cortex and just proximal to the posterior extension of Blumensaat's line. Intra-operative fluoroscopy can be used to accurately identify this position.
Schottle et al have described the radiographic landmark to be 1 mm anterior to the posterior cortex extension line, 2.5 mm distal to the posterior origin of the medial femoral condyle, and proximal to the level of the posterior point of the Blumensaat line.
Redfern et al evaluate this radiographic point and found it to be within 4mm of the true attachment on anatomic dissection.
This is demonstrated in Illustration A: the star shows the correct location anterior to the posterior cortical extension line (solid black line), proximal to Blumensaat's (red) line, and between the posterior origin of the medial femoral condyle and the posterior aspect of Blumensaat's line (perpendicular dashed lines).
Redfern J, Kamath G, Burks R.
Am J Sports Med. 2010 Feb;38(2):293-7. Epub 2009 Oct 12. PMID: 19822768 (Link to Abstract)
Redfern, AJSM 2010
Demonstration of hamstring autograft reconstruction of the medial patellofemoral...
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A 27-year-old football player sustains an acute lateral patellar dislocation. Which of the following is the most likely site of injury seen on MRI?
Midsubstance oblique retinacular ligament rupture
Soft-tissue avulsion of medial patellofemoral ligament
Midsubstance medial patellofemoral ligament rupture
Partial quadriceps tendon rupture
Bony avulsion of medial patellofemoral ligament
The most common site of medial patellofemoral ligament (MPFL) injury is a soft-tissue avulsion injury of the ligament. Both midsubtance and soft tissue avulsions are more common than bony avulsions.
Bony avulsion off the patella can occur as well, and according to the referenced study by Torisuka et al, the MPFL remains attached to the medial patellar fragment and excellent clinical and radiographic results can occur with open reduction and fixation with suture anchors.
The reported study by Nomura et al reported that MRI is >80% sensitive and >80% specific (regarding location) for detecting MPFL injuries as well as their location. In addition, they noted a 96% MPFL injury rate with patellar dislocation.
Toritsuka Y, Horibe S, Hiro-Oka A, Mitsuoka T, Nakamura N.
Knee. 2007 Dec;14(6):429-33. Epub 2007 Sep 19. PMID: 17884512 (Link to Abstract)
Nomura E, Horiuchi Y, Inoue M.
Knee. 2002 May;9(2):139-43. PMID: 11950578 (Link to Abstract)
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A high school softball player has chronic activity-related anterior knee pain without a history of instability. Which radiographic measurement is used to indicate when a lateral retinacular release may be helpful?
Lateral patello-femoral angle
Patellar height index
The lateral patello-femoral angle is the angle formed by lateral patellar facet and a line drawn across most prominent aspects of anterior portion of the trochlea on a CT scan or Sunrise view radiograph. If there is a negative patellar tilt on this measurement, the patient may benefit from a lateral release for pain relief. Lateral release is not used for instability. The sulcus angle refers to the depth of the trochlea; the congruence angle measures the relationship of the center of the patella to the center of the trochlea. These are used to assess malalignment and instability.
Nha KW, Papannagari R, Gill TJ, Van de Velde SK, Freiberg AA, Rubash HE, Li G.
J Orthop Res. 2008 Aug;26(8):1067-74. PMID: 18327809 (Link to Abstract)
Nha, JORE 2008
Grelsamer RP, Weinstein CH, Gould J, Dubey A.
Knee. 2008 Jan;15(1):3-8. Epub 2007 Nov 26. PMID: 18023186 (Link to Abstract)
Average 3.0 of 33 Ratings
An athlete sustains a traumatic patellar dislocation. The MRI shows a hemarthrosis with a floating osteochondral fragment. Which of the following is the most likely site of origin for the loose fragment?
The lateral patellar facet
The medial patellar facet
The odd patellar facet
The medial trochlea
The central trochlea
Lateral patellar dislocations are by far the most common. The medial facet of the patella will impact on the lateral trochlear ridge. Either of these would be acceptable answers, but lateral trochlea is not listed. Even without an osteochondral fracture, an MRI of an acute patellar dislocation will generally show bone bruises in these two locations.
Nomura looked at 39 consecutive arthroscopies after lateral dislocation and 95% had patellar chondral defects. They also reported that the medial facet of the patella is the most commonly injured site of the patella.
Nomura E, Inoue M, Kurimura M
Arthroscopy. 2003 Sep;19(7):717-21. PMID: 12966379 (Link to Abstract)
Nomura, ASCOPY 2003
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You see a patient in the emergency room with an acute lateral patellar dislocation. Which of the following factors is associated with the highest risk of persistent patellar instability?
Previous patellar instability event
Amount of lateral patellar tilt
Females (not males) have a higher incidence of patellofemoral instability due to their increased Q-angle. The Q-angle or quadriceps angle is the angle formed by the intersection of a line from the ASIS to the patella and from the patella to the tibial tubercle as demonstrated in Illustration A. Normal Q-angle in males is 14 degrees and in females is 18 degrees. A higher angle means that there is a larger lateral vector force on the patella, which predisposes to lateral patellar instability. While an increased Q-angle increases the chance for dislocation, a previous history of dislocation is the strongest predictor.
Fithian et al prospectively followed 189 patients for 2-5 years and found that the risk was highest among females 10 to 17 years old and those with previous instability episodes. Patients with a prior history had 7 times higher odds of subsequent instability episodes during follow-up than first time dislocators.
Fithian DC, Paxton EW, Stone ML, Silva P, Davis DK, Elias DA, White LM
Am J Sports Med. 32(5):1114-21. PMID: 15262631 (Link to Abstract)
Fithian, AJSM 2004
All of the following are predisposing factors for lateral patellar dislocation in a native knee EXCEPT?
Excess femoral internal rotation
Excess external tibial rotation
Lateral femoral condylar hypoplasia
Insufficiency of the vastus lateralis
Predisposing factors to lateral patellar dislocation include: excess femoral internal rotation, external rotation of the tibia, lateral femoral condyle hypoplasia, insufficiency of the VMO, an increased Q angle, a tight lateral retinaculum, patella alta, patella tilt, generalized ligamentous laxity, and patellofemoral dysplasia. The common theme throughout this list of predisposing features is an inequality in forces acting medially and laterally on the patella, with resultant higher rates of lateral patellar dislocation.
Dejour et al examined CT scans on 134 patients treated for patellar instability. They identified 4 common factors the unstable symptomatic knees: 1. Trochlear dysplasia (85%), 2. Quadriceps dysplasia (83%), 3. Patella alta (24%), 4. Tibial tuberosity-trochlear groove, pathological when greater than or equal to 20 mm (56%).
Dejour H, Walch G, Nove-Josserand L, Guier C.
Knee Surg Sports Traumatol Arthrosc. 1994;2(1):19-26. PMID: 7584171 (Link to Abstract)
Dejour, KSSTA 1994
Average 3.0 of 26 Ratings
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HPI - 14 year old playing soccer and sustained twisting injury. Fell to the ground. Presented to me with swollen knee. Place in KI and MRI obtained.
MRI shows significant lateral patellar subluxation with some tilt.
Trochlear dysplasia (flat trochlea)
Large medial facet chondral deficiency with loose fragment in suprapatellar pouch.
Medial patellar facet fx.
MPFL seems to be attached to medial fx fragment.
I measured TTTG to be 19-20
I did not appreciate patella alta.
What are your guys thoughts?
Scope and see if cartilage piece can be fixated?
Or let medial facet fx heal then go back and do tibial tubercle transfer with lateral release, medial plication / mpfl and denovo for chondral defect?
What would be your next step in treatment of this patient?
HPI - 25 yo laborer that was dancing at his bachelor party with first-time patella dislocation. evidence of large (approx 2cm)chondral loose body from medial facet with small amount of bone attached to small portion of loose body. TT-TG ratio is normal. In addition to MPFL repair/recon how would you treat the largely chondral fragment with small amounts of bony attachment.
would your treatment include attempted fixation of segments with attached bone, debridement, OATS, microfracture?
would you use bioscrews or acutrax metal screws for any attempted refixation??
deNovo is not available due to insurance restriction.
what would your treatment be for the largely chondral defect with small areas of bony attachment?
HPI - 27 yr F. Multiple knee instability episodes. Many patellar dislocations when teenager. Was a dancer. Has generalized ligamentous laxity.
Had MPFL repair and lateral release 12 years ago. Did not do well after surgery.
Main complaint is instablity.
On exam very lax patella. + apprehension. 4 quadrant excursion.
Failed conservative tx.
+ patella alta
Caton deshamps 1.3
Trochlear dysplasia Dejour type C
+ acl tear
What to do now?
Tibial tubercle tx with distalization and revision mpfl reconstruction
When to reconstruct ACL? Do all one surgery or stage?
HPI - 18 yo following patella dislocation with 12x11mm chondral defect at the median ridge with several chondral loose body fragments. TTTG is 14. In addition to MPFL advancement and lateral release what would be your cartilage restoration technique of choice? Insurance carrier in this region will not pay for DeNovo.
Which cartilage restoration technique would you select?
HPI - Sustained atraumatic patellar dislocation while walking at age 10. Full dislocation, self-reduced. Underwent PT. Sustained another while running. Underwent PT. Then a third dislocation.
What is the next step in treatment?
HPI - 21 year old female with history of recurrent dislocation patella was operated 2yrs back .lateral release ,proximal and distal alignment were performed .intraoperatively there was no dislocation. patient was asymptomatic for one year when after fall she again developed symptoms of recurrent dislocation of patella dwhich takes place in flexion beyond 100 degree
what should be the further treatment plan
HPI - 22 y/o male s/p traumatic patellofemoral dislocation 9 months ago. Failed conservative tx/6 months of PT. Patellofemoral dislocation now occurs ~2x/month.
What would you do for this patient to correct patellofemoral instability?
HPI - Patient underwent a RIGHT tibial tubercle transfer, VMO quadricepsplasty, and lateral release when she was 16 for recurrent dislocation. It was done out of state. She has had multiple episodes of LEFT patella subluxation over the years. She dislocated her LEFT patella for the first time one week ago when she slipped in her bathroom. She has donet PT and taping of the LEFT and RIGHT in her teenage years, but has not done any recent PT. She is pushing for surgery to prevent any further instability as she has been through this on the RIGHT side before. States "I know this won't get better with PT. I've already been through it on the right side."
Imaging notable for LEFT sided MPFL tear, large lateral meniscus tear, TT-TG 9mm, Q-angle 13 degrees. Trochlear dysplasia evident on MRI below.
How would you treat this patient?