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What type of tissue is formed by the activation of marrow mesenchymal cells following subchondral drilling of an 8x7 mm osteochondral defect?
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Subchondral drilling of an osteochondral defect will create fibrocartilage tissue.
The premise of subchondral drilling is to utilize the marrow stimulating effects of subchondral bone to create fibrocartilage in place of hyaline cartilage defects. Penetrating the subchondral plate will expose the damaged area to progenitor cells that reside in the subchondral bone. Activating of progenitor cells will create fibrocartilaginous scarring. Fibrocartilage is biologically and biomechanically inferior to native hyaline cartilage. However, this repair process will create a congruent joint surface and prevent further deterioration of the adjacent cartilaginous tissue.
Mithoefer et al. examined forty-eight patients with isolated full-thickness articular cartilage defects of the femur that were treated with a microfracture technique. MRI imaging showed good or moderate tissue repair and filling in 83% of patients. These patients showed greater improvements in their SF-36 score after treatment compared to the other 17% of patients with low tissue repair and filling.
Illustration A shows a diagram of bone-marrow stimulating technique of an osteochondral defect. The steps of this technique include (from A-D): debriding the sclerotic bone, trimming the edges of unstable articular cartilage, drilling past the subchondral plate (~4mm), and obtaining sufficient converge between holes to allow for a mesenchymal clot.
Answer 1: Elastic cartilage is mostly found in the external ear, epiglottis and larynx.
Answer 3: Hyaline cartilage is mostly found in in the ribs, nose, larynx, trachea.
Answer 4: Subchondral drilling has been shown to alter the subchondral bone plate and trabecular bone composition by causing micro cysts and intralesional osteophytes that later fill in with cancellous bone.
Answer 5: Hypertrophic chondrocytes are cells not tissue. Subchondral drilling has no effect on their activity.
Mithoefer K, Williams RJ, Warren RF, Potter HG, Spock CR, Jones EC, Wickiewicz TL, Marx RG
J Bone Joint Surg Am. 2005 Sep;87(9):1911-20. PMID: 16140804 (Link to Abstract)
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Average 4.0 of 10 Ratings
A 24-year-old female has moderate arthrosis of the medial facet of the patella and the medial femoral condyle. Which of the following procedures is contraindicated?
Anterior (Maquet) tibial tubercle osteotomy
Anteromedial (Fulkerson) tibial tubercle osteotomy
Anterolateral tibial tubercle osteotomy
Medial opening wedge high tibial osteotomy
Lateral closing wedge high tibial osteotomy
Anteromedial (Fulkerson) tibial tubercle osteotomy is contraindicated in patients with significant arthrosis of the medial facet of the patella and the medial femoral condyle.
Anteromedial tibial tubercle osteotomy (Fulkerson procedure) involves the transfer of the tubercle to a more anterior and medial location. Changing the vector of the extensor mechanism can help reduce lateral patellar subluxation/dislocation and concomitantly unload areas of arthrosis on the distal and lateral aspects of the patella. When performing a tibial tubercle transfer, the surgeon should beware of proximal lesions or medial facet or condylar lesions. Thus, intact proximal and medial cartilage is required to obtain the maximum benefit from this procedure.
Pascual-Garrido et al, in a Level 4 study, reviewed 62 patients who underwent autologous chondrocyte implantation of the patellofemoral joint for defects an average size of 4cm(2). Those that underwent anteromedialization tended to have better clinical outcomes than those without realignment, however 44% of the patients still required a subsequent procedure.
Paulos et al, in a Level 3 study, prospectively followed 25 patients with a dislocating patella that underwent a derotational high tibial osteotomy, medial, or anteromedial tibial tubercle osteotomy. There were no dislocation recurrences in either group and 92% of the patients stated that they were happy with the results of their surgery and would undergo the procedure again.
Illustration A shows a video of a Fulkerson osteotomy being performed on a cadaveric specimen.
Pascual-Garrido C, Slabaugh MA, L'Heureux DR, Friel NA, Cole BJ
Am J Sports Med. 2009 Nov;37 Suppl 1:33S-41S. PMID: 19861699 (Link to Abstract)
Paulos L, Swanson SC, Stoddard GJ, Barber-Westin S.
Am J Sports Med. 2009 Jul;37(7):1288-300. Epub 2009 Jun 2. PMID: 19491333 (Link to Abstract)
Average 3.0 of 21 Ratings
Following a medial femoral condyle osteochondral autograft mosaicplasty, which of the following statements best describes the fixation of the graft?
Graft fixation strength increases linearly with time until subchondral union at 3 months
Graft fixation strength initially decreases during the early healing phase, and then increases with subchondral bone healing
Graft fixation strength does not change during the first 3 months following surgery
Graft fixation strength is enhanced by early weight bearing
Graft fixation strength initially increases over the first 6 weeks, then recedes with bony remodeling
Studies have shown graft fixation strength initially decreases during the early healing phase, and then increases with subchondral bone healing.
Following mosaicplasty, appropriate post-operative rehabilitation and weight-bearing status must be based upon the fixation of the osteochondral autograft plugs. In addition, early non-weight bearing motion is important to prevent stiffness and protect the joint surfaces with synovial fluid.
Whiteside et al. performed a porcine study evaluating the fixation strength of osteochondral autograft mosaicplasty during the first week following implantation. The graft fixation was notably weaker one week following surgery due to the post-operative response and host remodeling. These results suggest that protected weight bearing should be used until the osteochondral plugs have healed into the subchondral bone, generally by 3 months.
Whiteside RA, Bryant JT, Jakob RP, Mainil-Varlet P, Wyss UP.
J Biomech. 2003 Aug;36(8):1203-8. PMID: 12831747 (Link to Abstract)
Average 3.0 of 15 Ratings
A 32-year-old female is referred to you for definitive treatment of a symptomatic focal chondral defect on her medial femoral condyle. A photograph from a recent diagnostic arthroscopy shows the defect (Figure A), which measured 25 x 25mm after debridement. What surgical treatment would you recommend?
Osteochondral autograft with 1-2 plugs
Based on the age of this patient and the size of this lesion (2 x 2.5 = approx 5cm square) an osteochondral allograft plug is the best choice. The results of microfracture are better for contained defects less than 2cm square. Autografts are generally reserved for smaller defects as well because harvesting enough plugs to fill this defect may lead to significant donor site morbidity. Chondroplasty and abrasion arthroplasty are not good solutions to this chondral defect in a young symptomatic patient. Autologous chondrocyte implantation (ACI) would also be a correct response, but it was not listed.
Bert discusses the science, histology, history, and clinical results of abrasion arthroplasty for treatment of osteoarthritis of the knee.
Alford et al. review the indications for treatment of chondral defects and describe the various treatment options. In addition, they discuss clinical scenarios regarding comorbid conditions including ligament instability, meniscal deficiency, and malalignment by developing a treatment algorithm (Illustration A).
Alford JW, Cole BJ.
Am J Sports Med. 2005 Mar;33(3):443-60. PMID: 15716263 (Link to Abstract)
Average 3.0 of 32 Ratings
A patient with a symptomatic chondral defect undergoes the arthroscopic procedure seen in Figure A. The reparative tissue would best be described as which of the following?
The figure is an arthroscopic photo of a microfracture procedure, which creates a reparative tissue best described as fibrocartilage. Microfracture is a marrow stimulation technique where stem cells from the medullary canal are given access to the base of the lesion by making small perforations in the subchondral bone. The rationale for this technique is based on these stem cells differentiating into cells that will produce an articular cartilage repair. However, biopsy findings in animals and humans have demonstrated primarily a fibrocartilagenous repair tissue and not true articular cartilage regeneration. The collagen type found in hyaline or articular cartilage is of the type II variety. Fibrocartilage possesses some type II, but is mostly type I and III cartilage.
Both the Intructional Course Lecture and the textbook by Buckwalter provide an in-depth review of articular cartilage biology and the background for chondral resurfacing techniques.
2. Fibrous tissue is created by fibrocytes and lacks type II collagen.
3. Elastofibroma is a distractor (elastofibroma dorsi is a fibrous tumor with a predeliction for the scapulothoracic joint).
4. Hyaline cartilage is true articular cartilage with predominantly type II collagen. It also has columnar organization and a lamina splendens (which differentiates it from what has been called hyaline-like tissue).
5. Chondromalacia refers abnormal softening of the cartilage and is a common pathologic condition of the the knee.
Average 4.0 of 17 Ratings
All of the following are acceptable scenarios for the use of autologous chondrocyte implantation (ACI) in the patellofemoral joint EXCEPT:
Grade 4 lesion of the medial femoral condyle
Grade 4 lesion of the trochlea
Joint space narrowing on Merchant view
Varus mechanical axis on standing full length radiograph
Concomitant anteromedial tibial tubercle transfer osteotomy (Fulkerson's)
Joint space narrowing on a merchant view is a contraindication for autologous chondrocyte implantation for patellofemoral arthritis.
Saleh et al states ACI relies on intact, full-thickness cartilage margins to maintain the joint space so that the growing cartilage repair tissue may fill the defect. Cartilage loss seen with diffuse arthritis is not amenable to ACI. It is critical that there is a preserved patellofemoral joint space as seen on a Merchant or skyline view. The article states that ACI can be used for grade 3 or 4 defects on the patella or trochlea. Concomitant realigment procedures of the patellofemoral joint (such as lateral release, medial tubercle transfer, or anteromedial tubercle transfer) and the tibiofemoral joint (high tibial osteotomy) are indicated in the presence of mechanical malalignment.
The article by Peterson et al followed 94 patients for 2-9 years and found graft failure in only seven patients. Histologic analysis of 37 "second-look" arthroscopy biopsy specimens showed a correlation between hyaline-like tissue and good to excellent clinical results.
NOTICE: ACI is not FDA approved for use on the patella and the use of ACI "off-label" should be discussed with patients preoperatively.
Saleh KJ, Arendt EA, Eldridge J, Fulkerson JP, Minas T, Mulhall KJ.
J Bone Joint Surg Am. 2005 Mar;87(3):659-71. PMID: 15741637 (Link to Abstract)
Peterson L, Minas T, Brittberg M, Nilsson A, Sjögren-Jansson E, Lindahl A.
Clin Orthop Relat Res. 2000 May;(374):212-34. PMID: 10818982 (Link to Abstract)
Case example of Carticel cartilage restoration of the knee.
Average 2.0 of 52 Ratings
HPI - 36 year old active male with lateral knee pain. Previous hx of acl recon. Did well with that. Recently started to have lateral knee pain.
Initial arthroscopy did reveal Grade 3-4 lateral joint chondromalacia. Well contained lesions. This was debrided and microfractured. ACL graft was intact.
Continued to have pain. all pain is lateral knee.
Now my Plan is for ACI vs DeNovo.
Full length scanogram films shows mechanical axis falls through the lateral joint. Not terrible but not normal either.
Any indication for distal femoral osteotomy along with cartilage restoration? Stage or do at same time?
Plan of care?
HPI - Painless knee crepitus
What is the MRI finding?
HPI - Highly competitive high school football player presents with knee pain after suffering patellar dislocation during football game one week prior to presenting in the clinic.
How would you treat this patient?
HPI - Former elite marathon runner has been unable to exercise for a year. She was diagnosed with a medial cartilage defect and underwent a microfracture at local hospital. She had no improvement after 6 months. MRI shows 20x20 MFC defect with scant fill and intact subchondral bone.
How would you treat this patient with a symptomatic full thickness MFC chondral defect and previous failed microfracture?
HPI - 17yo F bilateral knee AVN. Pain and swelling limiting activities. MRIs of both knees show AVN of the weightbearing portion of both medial and lateral condyles.
Session IV Author: Christian Lattermann, MD Duration: 11:30
Session IV Author: Andreas H. Gomoll, MD Duration: 11:43
Session IV Author: Jack Farr, II, MD Duration: 10:55
Session IV Author: Adam Yanke, MD Duration: 10:58
Arthroscopic MicroFracture Trochlear Groove by Chad Smalley MD
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