MRI

Discoid Meniscus

DefinitionDiscoid Meniscus

 

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

 

Chronic PLC Management

Issues

 

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

 

Results

 

Posterolateral Corner Reconstruction

 

Moulton et al. Am J Sports Med 2016

- systematic review of PCL reconstruction for chronic injuries

- 450 patients

Background

 

ACL Normal ArthroscopyACL Normal Arthroscopy

 

Anatomy

 

Developmental Anatomy

 

Knee joint first appears as a mesenchymal cleft at 8 weeks gestation

- ACL and PCL separate entities by week 10

MCL and Posteromedial Corner

AnatomyMCL anatomy

 

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

AVN

 

SONK              vs                          Atraumatic AVN

 

>55                                              Often mid 30's

Syringomyelia

Definition

 

Progressive and  chronic disorder associated with cord cavitation & gliosis

 

Effects

 

Muscle wasting

Dissociate anaesthesia

Scoliosis

Neuropathic arthropathy

 

Epidemiology

 

M > F

No familial tendency

 

Aetiology

 

1. Idiopathic

 

Synovial Sarcoma

Epidemiology

 

4th most common STS

- 10-35% of STS

 

Peak age 3rd-4th decade

- rare in children

 

Pathology

 

Cellular characteristics suggest tumour arises from primitive synovial cells

- rarely actually occurs within joint

 

Characteristic

 

Occasionally metastasis to lymph nodes (5-7%) 

- like Epitheloid Sarcoma 

Liposarcoma

Definition

 

STS composed of malignant lipoblasts

 

Epidemiology

 

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