Abstract
Background:
Knee femoral chondral pathology is frequently encountered during knee arthroscopies. Based on previous studies, the unaddressed, painful, poor knee function progresses into arthritis. Addressing this scenario with a simple, less invasive arthroscopic procedure may provide a simple solution for this cohort of patients.
Indications:
The arthroscopic autologous cultured chondrocytes on a porcine collagen membrane (matrix-induced autologous chondrocyte implantation [MACI]) procedure is indicated when chondral lesions are located on the femoral condyles, with symptoms consistent with the location that corresponds to magnetic resonance imaging findings between 2 and 4 cm2, contained with a stable rim, and grade 3 to 4a International Cartilage Repair Society defects.
Technique Description:
This novel technique for arthroscopic delivery of MACI for defects on femoral condyles was developed as the next step in the evolution of the autologous chondrocyte implantation technology. The technique describes the newly developed instruments—a unique measuring probe, 3 types of curettes, the arthroscopic and MACI membrane cutters, and the V-shuttle delivery device. Also, attention is paid to the medial and lateral approach, defect preparation, fluid control, implant and fibrin sealant delivery, and simple closure. Arthroscopic surgical procedures typically result in less pain after surgery, requiring fewer pain medications, earlier and improved range of motion/function, less postoperative muscle weakness, and faster recovery, and for patients concerned about cosmesis, arthroscopic joint repair may reduce scarring. Discussed are the special differences between open and arthroscopic delivery of MACI, summarizing the pros and cons.
Results:
Compared to many other knee ligament or meniscus arthroscopic procedures, the addition of arthroscopic delivery of MACI for defects on knee femoral condyles is appealing and easy to implement by an experienced surgeon. The development of instruments simplified the procedure and elevated it to an art form.
Discussion/Conclusion:
Chondral lesions of the femoral condyles of the knee can effectively be treated with the arthroscopic MACI technique. Potential benefits include minimal surgery disruption, concomitant knee arthroscopic procedures, cosmetic appeal, improved quality of life, and level of function.
Patient Consent Disclosure Statement:
The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.
This is a visual representation of the abstract.
Keywords
Video Transcript
Dr Michael Kuhn is presenting arthroscopic delivery of autologous cultured chondrocytes on a porcine collagen membrane (matrix-induced autologous chondrocyte implantation [MACI]) for defects on the femoral condyles.
Background
Today, I will present exciting information on this new technology for precise and reproducible arthroscopic implantation of MACI.1,2,11 Autologous chondrocyte implantation has been available for the past 30 years and continues to be an evolving technology. MACI Arthro is the latest in that technology, with instrumentation designed to create a reproducible technique for arthroscopic delivery while maintaining cell viability on the implant.
Indications
The indications for MACI arthroscopic delivery are similar to open techniques. MACI arthroscopic indications include cartilage defects that are up to 4 cm2 in size and are accessible through an arthroscopic technique. 12 With any procedure, the contraindications are important to consider. 12
Technique Description
Here you will see the various cannulas, curettes, measuring device, and implantation instruments, including the V-shuttle available for your case. As with any arthroscopic surgery of the knee, proper portal establishment is key to success. With this procedure, hugging the patella tendon, as demonstrated, will allow for more optimal portal placement, as well as ease defect preparation and ultimate graft implantation. Once the lateral portal is established, utilizing a spinal needle, the anterior medial portal is established perpendicular to the defect. This will facilitate a successful surgical procedure, including cannula placement, use of the Arthro Cutter (Vericel), and V-shuttle devices. Generous fat pad resection will optimize visualization of the defect and ease with arthroscopic resection and implantation. Using an electric cautery device to coagulate all punctate bleeders aids in meticulous hemostasis for the procedure. A helpful tool for arthroscopic MACI is the creation of suture stitch retractors to aid in the visualization of the defect. A pearl is to use absorbable sutures and stacked mulberry knots to aid in capsular retraction. Using a spinal needle, a polydioxanone suture can be passed percutaneously into the joint. Optimal placement of the suture needle is generally higher than the working portal to allow for optimal capsule retraction, generally with 2 to 3 sutures required. At the end of the case, the sutures can easily be removed and discarded. The innovative arthroscopic flexible measuring device allows precise measurement of the defect in both anterior-posterior and medial-lateral directions. The arthroscopic measuring device allows for 360° of rotation with a single-hand technique. There are 2-mm intervals clearly marked on the guide, including bulb marks at the 10-mm intervals. The cannula is designed specifically for Arthro MACI, allowing the atraumatic insertion of the graft through the cannula. During placement of the cannula, aim for the intercondylar notch and thread the cannula in a clockwise direction, which will allow easy access to the joint. Once the cannula is inserted, you can see, as visualized in the slide, the ability to arthroscopically evaluate the knee and prepare the cartilage defect. Once a cannula is placed in the intercondylar notch, it can be rotated toward the defect, ensuring a perpendicular approach for ease of defect preparation and graft delivery. Pictured are the 3 Arthro Cutters available for defect preparation, including a 2.0-, 2.8-, and 3.7-cm2 device, allowing the surgeon versatility and selection for patients’ individual articular cartilage defect. When inserting the Arthro Cutter through the cannula, like placing the cannula, first insert the device, aiming toward the intercondylar notch. Once it has cleared the cannula, the device can easily be deployed and used to define the defect to be treated. With a cutter perpendicular to the defect, forward pressure on the cutter and gentle tapping with a small mallet will aid in defining the perimeter of the defect to be treated. The cutter is locked in the desired position to ensure equal depth of penetration for the entire cutter circumference. Like inserting the cutter, deliver the device to the intercondylar notch, then flip the cutter for retraction or removal. Ensure that the Arthro Cutter is not within the cannula when flipping it, allowing for a smooth removal. Depending on the patient's unique defect, any and all of the 3 disposable curettes available may be required. When utilizing the curettes, manipulating the curette as close as possible to the cannula will allow for optimal control of the resection. Pictured is the open ring curette, which is a workhorse for this procedure. When needed, removal of the arthroscopic cannula will allow for more mobility with the curettes within the knee. Switching between the medial and lateral portals for viewing and working aids in the ease of defect preparation. All defects are unique in location, size, and contour, and the versatile cutters allow for precise defect preparation. The rake curette is helpful in creating the desired perpendicular margins at the periphery of the defect. It is also a good utility device for larger areas of cartilage and fibrocartilage removal. The square curette is uniquely sharp on both ends and sides. It is useful for all cartilage resections and specifically helpful with more posterior resections. Once the initial resection is complete, placing the sizer in the knee provides feedback as to the appropriateness of the resection and to define additional areas still requiring further debridement. Final defect touch-ups are demonstrated here after reassessment with the Arthro Cutter device. The shaver is utilized for the removal of any remaining cartilage fragments, including loose cartilage debris within the joint. At this point, a thorough lavage of the joint will ensure the removal of all remaining soft tissue debris. After the final debridement, the Arthro Cutter is introduced for a final assessment of defect preparation and confirmation of the appropriate resection. As demonstrated, using the arthroscopic shaver first will ensure that the majority of fluid within the knee is removed. Once the fluid is removed, pulling on the traction sutures will again confirm appropriate visualization of the defect for implantation. Using a pinch-and-pull technique, the dam can easily be removed from the cannula. At this point, atraumatic introduction of a sponge gauze will allow for further drying of the defect. The cannula allows for easy introduction and removal of the sponge. The Arthro MACI sponge applicator is now used for fine-tuning the drying of the defect. Using atraumatic forceps, the membrane is placed on the cutting device with a notch in the lower left corner, indicating that the cells are facing the surgeon. The cutting guide appropriate for your Arthro Cutter is placed on the graft. A pearl is to place the cutting guide toward the edge of the membrane. This will allow for additional membrane harvest if needed, as well as easy removal of the membrane once it has been cut. With gentle thumb pressure in 1 corner of the cutting guide, a small amount is used to cut the graft. This is best facilitated with multiple firm taps with a mallet on the cutting device. Switching to the other side of the cutting guide, this process is repeated until the depth gauge portion of the cutting guide is flush with the membrane. An easy technique to ensure the membrane has been completely cut is to lift off the membrane with forceps, and the remaining membrane should easily pull away. Gently remove the guide to reveal the graft. The membrane is placed cell side up equally on both sides of the shuttle, ensuring that the visible shuttle deployment sides are covered by the graft. By ensuring equal loading of the membrane on both sides of the shuttle, intra-articular graft deployment easily occurs. It is recommended to load the V-shuttle device with a graft before placing the fibrin glue base layer in the condylar defect. A little goes a long way: placement of the fibrin glue at the superior edge of the defect will allow for uniform coverage of the defect in the base. The outer fins of the V-shuttle device should align with the long axis of the cartilage defect. This is generally in a superior-to-inferior position in line with the lesion. Using a hover-and-deploy approach, the graft is placed over the defect and deployed with the V-shuttle plunger. Using the MACI tip applicator, fine adjustments and gentle manipulation of the graft can be performed. An additional thin layer of fibrin glue is placed at the periphery of the graft using a similar technique to that used for the base layer. Through arthroscopic visualization, graft evaluation with range of motion (ROM) confirms stable placement and fixation of the graft.
An arthroscopic preparation and delivery allows for smaller incisions, 7 no unnecessary arthrotomies, enhanced visualization of the defect preparation and graft placement, and reduced postoperative morbidity. 6 The arthroscope enables improved ability for second-look evaluations and a lower inflammatory response. 9
Results
Rehabilitation following MACI Arthro is key to success. ROM exercises are initiated with progression of motion. Toe-touch weightbearing (WB) is started immediately, progressing to full WB and full ROM. Additional rehabilitative techniques, including the use of a continuous passive motion machine and isometric contraction of the musculature of the leg, are key to success. Five-year follow-up was available for the first 31 patients who underwent MACI via an arthroscopic approach. This resulted in an 80% to 90% success rate and pain relief, improvement of activities of daily living, return and participation in sports, and tissue fill in the defect. 5 Clinical implications were reported by Edwards et al 6 comparing the advantages of the mini-open technique versus the arthroscopic approach.
Discussion/Conclusion
Arthroscopic delivery of the MACI implant results in a new advancement for the MACI procedure. It provides a less invasive delivery approach, which may result in decreased surgical times, less postoperative pain, lower surgical site morbidity, and faster surgical recovery for patients.3,8,10 It allows for a smooth surgical procedure utilizing both portals for preparation and delivery of the graft. The innovative instrumentation dramatically shortens any learning curve and allows for a very reproducible, reliable Arthro MACI procedure (Table 1).4,5,12
Patient Profile: Arthro MACI vs Standard
MACI, matrix-induced autologous chondrocyte implantation.
Footnotes
Acknowledgements
The author thanks Sue Rothberg for video production.
Submitted September 8, 2024; accepted January 7, 2025.
One or more of the authors has declared the following potential conflict of interest or source of funding: M.A.K. is a consultant for Vericel Corporation and receives an honorarium for speaking engagements, education, travel, and lodging. AOSSM checks author disclosures against the Open Payments Database (OPD). AOSSM has not conducted an independent investigation on the OPD and disclaims any liability or responsibility relating thereto.
