Discoid Meniscus
Definition
Round or "D" shaped rather than crescenteric meniscus
- occupies > 70% of tibial surface
- 90% occur on lateral side
Epidemiology
Uncommon
- 1:100
- usually presents in children & adolescents
Round or "D" shaped rather than crescenteric meniscus
- occupies > 70% of tibial surface
- 90% occur on lateral side
Uncommon
- 1:100
- usually presents in children & adolescents
Limb alignment
Risk that late posterolateral corner reconstruction will fail in the setting of the varus knee
- varus knee alignment and varus thrust in stance phase
- consider osteotomy first in this setting
Posterolateral Corner Reconstruction
Moulton et al. Am J Sports Med 2016
- systematic review of PCL reconstruction for chronic injuries
- 450 patients
LCL / Popliteus / Popliteofibular ligament
Laprade et al. AJSM 2003
https://pubmed.ncbi.nlm.nih.gov/14623649/
1. Lateral collateral ligament
Femoral attachment
Developmental Anatomy
Knee joint first appears as a mesenchymal cleft at 8 weeks gestation
- ACL and PCL separate entities by week 10
1. Seebacher's 3 layers of the medial knee
Layer 1
- sartorius and sartorius fascia
Layer 2
- superficial MCL
- posterior oblique ligament
- semimembranosus
Layer 3
- deep MCL (meniscofemoral and meniscotibial ligament)
- posteromedial capsule
2. MCL
Superficial MCL
>55 Often mid 30's
Progressive and chronic disorder associated with cord cavitation & gliosis
Muscle wasting
Dissociate anaesthesia
Scoliosis
Neuropathic arthropathy
M > F
No familial tendency
1. Idiopathic
Type I: Undisplaced avulsion fracture
Type II: Anterior portion displaced & hinged
Type IIIA: Displaced
Type IIIB: Displaced & Rotated
4th most common STS
- 10-35% of STS
Peak age 3rd-4th decade
- rare in children
Cellular characteristics suggest tumour arises from primitive synovial cells
- rarely actually occurs within joint
Occasionally metastasis to lymph nodes (5-7%)
- like Epitheloid Sarcoma
STS composed of malignant lipoblasts
Common
- 10% of STS
- second only to MFH
Occurs almost exclusively in adults
Males age 40-60
Can be multiple origin -> examine patient
Rarely arise from lipoma