Via Research Recognition Day 2024 VCOM-Carolinas

Clinical Case-Based Reports

ARTHROSCOPIC LATERAL SEGMENTAL MENISCAL ALLOGRAFT TRANSPLANT (SMALT) WITH OSTEOCHONDRAL ALLOGRAFT TRANSPLANT (OCAS) OF LATERAL FEMORAL CONDYLE AUGMENTED WITH BONE MARROW ASPIRATE CONCENTRATE (BMAC) Max Muir, OMS-IV; Alyssa McMandon, OMS-II; Siena Lombardozzi; James McDermott, MD Medical Group of the Carolinas, Spartanburg, SC and Edward Via College of Osteopathic Medicine, Spartanburg, SC Abstract Case Discussion

The meniscus of the knee is a protective load-bearing structure. Meniscal damage alters load distribution and disrupts the natural weight-bearing surface. Segmental meniscal allograft transplantation (SMALT)s are a novel approach to treat focal meniscal defects. In this study, we present a surgical technique and a case involving a young, active female who underwent SMALT with osteochondral allograft transplantation (OAT) augmented with bone marrow aspirate concentration (BMAC). A 40-year-old former Division I volleyball player, with a history of an arthroscopic partial lateral meniscectomy and chondroplasty, presented with knee pain and magnetic resonance imaging (MRI) findings of a complex lateral meniscus tear. During initial arthroscopy, two separate tears were seen in the lateral meniscus, with segmental deficiency at the junction of the posterior horn and body. Additionally, a horizontal cleavage type tear was observed in the body. An attempt was made to repair the segmental deficiency which failed. The patient subsequently underwent a lateral SMALT where the allograft was soaked in the patient's BMAC. In addition, she received an OAT to the lateral femoral condyle. The patient was rehabilitated following two protocols: one for SMALT and another for OAT to the lateral femoral condyle. While medial SMALTs have been investigated, this is the first documented use of a lateral SMALT. Medial and now lateral SMALTs can be a viable solution for focal segmental meniscal deficiencies. • The menisci are two cartilaginous structures that play essential roles in knee kinematics and biomechanics. • The medial and lateral geniculate arteries supply blood to the periphery of the menisci (red-red zone), while the middle third of the meniscus still receives blood, albeit less than the periphery (red-white zone). 1,2 • Literature reports that approximately 50% of the load in the medial compartment and 70% in the lateral compartment is absorbed by the medial and lateral menisci, respectively. 1 • Menisci serve vital functions in load transmission, shock absorption, joint stability, lubrication, and proprioception. 1 o Hoop stress: dispersion of axial forces among circumferential fibers. • Mechanoreceptors, such as Golgi tendons, Pacinian corpuscles, and Ruffini endings are identified in the anterior and posterior horns. 1 • Absence of menisci leads to increased osteoarthritis progression, emphasizing the meniscus's role as a protective load-bearing structure. 1 • Meniscal Preservation Options o Meniscal repair, meniscal allograft transplantation (MAT), meniscal scaffolding transplantation (MST), and segmental meniscal allograft transplantation (SMALT). 3,4,5,6 o Choice depends on the patient's age, activity level, type of meniscal tear, and the surgeon's familiarity with the technique. • Surgical technique: Segmental meniscal allograft transplant (SMALT) with osteochondral allograft transplantation (OAT) augmented with bone marrow aspirate concentration (BMAC). Introduction

• Importance of menisci: • Vital for intra-articular neurosensory signaling to the spinal, cerebellar, and central nervous system. 1 • Aids in conscious perception for knee joint balance and stabilization. 1 • Removal increases contact pressures, affecting joint alignment, function, and stability. 1 • Rehabilitation • Limited weightbearing to heel touch for the first 6 weeks. • Maintained a straight leg position until the first follow-up appointment. • Gradual increase in range of motion: 0 to 30 degrees from weeks 1-2, 0 to 60 degrees from weeks 2-4, 0 to 90 degrees from weeks 4-6. • Meniscectomy consequences: • Increases articular contact pressure in the tibiofemoral joint. 7,8,9 • Leads to degenerative changes. 8,9 • Resection of 20% of meniscal tissue increases contact forces up to 350%. 8,9 • Shift to meniscal preservation: • SMALT ▪ Ideal for focal meniscal loss, considering shape, size, distribution, and location. 10 ▪ Patient profile: Former Division I athlete, active lifestyle, under 50 years, dedicated to rehabilitation. ▪ Limited long-term survivorship • MAT ▪ Results with mean survivorship at 10 years (73.5%) and 15 years (60.3%). 11 • MST ▪ 10-year survival rate (CMI 85%, Actifit 80%) with concerns about issues like fragmentation, shrinkage, and extrusion. 12,13

Figure 1. Measurement of the lateral segmental meniscal tear from previous lateral meniscectomy. • A 40-year-old former Division I volleyball player sought treatment at the sports medicine clinic due to left knee pain that developed four weeks ago. • Previous Surgical intervention involved a left knee arthroscopy, partial lateral meniscectomy, and chondroplasty. • Meniscal exams showed negative findings on the medial side but were positive for lateral joint line tenderness and provocative tests. • MRI confirmed lateral meniscus tear and subsequent chondral defects. • On diagnostic arthroscopy, two separate tears were identified in the lateral meniscus, with segmental deficiency at the junction of the posterior horn and body (approximately 10 x 15 mm) due to prior partial lateral meniscectomy, and a horizontal cleavage-type tear was observed in the body, which was rasped and repaired using one Stryker AIR plus all inside meniscus repair implant .

Figure 2. Integration of lateral segmental meniscal allograft transplant (SMALT) within the lateral meniscus. • The lateral SMALT was marked and cut to match the patient's deficiency. The allograft was soaked in the patient's BMAC and injected into the periphery. It was then placed in the knee, and sutures were used to secure it. Stryker AIR plus all inside meniscus repair implants were utilized to stabilize the allograft. The sutures were tied with alternating half-hitch knots, and the knee was taken through a range of motion, confirming the stability of the SMALT.

References

Figure 3. Osteochondral allograft transplant (OCA)

Gratitude is extended to the patient for generously permitting the utilization of her case and imaging. Our appreciation also goes to Spartanburg Regional Medical Center, Medical Group of the Carolinas, and VCOM for providing this invaluable learning experience.

• Diagnostic arthroscopy also demonstrated a 15mm x 25mm osteochondral defect of the lateral femoral condyle was noted. This was filled with an osteochondral autograft (OCA).

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2024 Research Recognition Day