All About Orthopaedic Pathology

(Medical Student Education Series: Core Orthopaedics)

ALL ABOUT

Orthopaedic Pathology copyright 2008 eugene [sic] with Conor

Paget’s disease Paget’s(osteitis deformans) is probably a viral infection of bone where there is disordered formation of bone resulting in deformity, weakened bone and 2° OA. It is common in the UK, Australia and NZ. Patients may also develop cardiac problems and nerve entrapment.

Paget’s disease (51M, pain and stiffness for years)

LARGE HEAD, 2°OA, COARSE TRABECULATION, OSSIFICATION OF PSOAS.

Large head, 2° OA, coarse trabeculae, ossification psoas

BROAD TRABECULAR, ACTIVE OSTEOBLASTS, CEMENT LINES & FIBROUS VASC. TISSUE.

THR

Infection • Infections in orthopaedics can be devastating. The infection maybe of bone(osteomyelitis,OM-1°/ haematogenous or 2°-post trauma /ORIF) or in joints septic arthritis).XR changes of OM are soft tissue swelling,demineralization,sequestra(dead bone) and involucrum(periosteal new bone). Treatment is rest, hydration, identifying the causative organism and surgery.

Osteomyelitis (with sequestrum) (21M, post MVA, open tibia #) OPEN # TIBIA

OPEN # TIBIA

OPEN REDN & EXT FIX.

POST-OP INFECTION

SEQUESTRUM, DEAD BONE

Gout Gout is a disorder of metabolism whereby there is hyperuricemia resulting in deposition of uric acid crystals in soft tissue olecranon bursitis) and in/around joints. XR changes of ‘punched-out’Pseudo erosions gout crystals in knee are typical. Punched out erosions

Gouty olecranon bursitis Picture 7

43 yo NZ Maori Picture 5

Picture 10

Picture 12

Tophus

Excising gout tophus

Loose bodies in joint (70F, pain and locking of knee) Picture 3

Picture 4

xx LOOSE BODIES

OA KNEE Picture 7

Removing LB at arthroscopy

Morton’s metatarsalgia/neuroma Is from repetitive microtrauma to foot digital nerves. Usually the common digital nerve to the 3rdwebspace. Patient has forefoot pain, feels walking ‘on pebble’. Treatment is better shoes and maybe surgery/neurectomy.

Morton’s(Bett’s) metatarsalgia (33F, pain in 2/3 space) PAIN USUAL SPACE

EXCISED NEUROMA EXCISION, Dorsal appr

Freiberg’s disease foot (78F, pain over 2nd metatarsal head) Stress overload to 2nd metatarsal head. Can be extremely painful. May need to be excised. Excised 2nd metatarsal head

Sclerosis 2nd met head & collapse joint surface. Arrow

Dupuytren’s disease An autosomal dominance disease characterized by abnormal proliferation of myofibroblasts and fibroblasts resulting in contractures of the hands/digits,feet and penis. Treatment is largely surgery (fasciectomy and rarely amputation).

Dupuytrens-straighten but if too deformed then amputate.

Osteoarthritis(OA) OA is a loss of the articular cartilage. Often the long term result of damage ( eg trauma). It maybe 1° or 2°. 2° from abnormal cartilage (e.g. ochronosis),abnormal bone ( e.g. radionecrosis,AVN) or abnormal loads( eg deformity from childhoodPerthe’s, SUFE, DDH and Paget’s). The XR changes are loss of joint space, sclerosis and osteophytes.

OA=loss articular cartilage; seen at arthroscopy

Knee replacement

OA-causes

DDH. 36F.PAINFUL HIPS. Childhood surgery. 2°OA. Bil THR.

Bil 2° OA

PERTHES.LARGE DEFORMED HEAD.

2°OA. Needed THR.

OA-causes RADIONECROSIS. 64m postradiotherapy for testicular Ca. Needed THR.

SEGMENTALAVN post sliding screw plate for #NOF. 35M. Needed THR.

DERMATOMYOSITIS 43 F with painful hip. 2° OA. Needed THR.

OA-causes SUFE

pistol-grip shape

2° OA as adult. Needed THR SUFE, left side, as child

Pin-in-situ; but still went onto 2°OA as adult

AVN hip (42F,on steroids for pemphigus, to THR) LARGE FLAP HIP

COLLAPSE OF SURFACE WITH 2° OA

FLAP IS CARTILAGE & BONE

THR

Meniscus

=Left meniscus (with permission JBJS(B). Fig 1, p 1550, Dec., 2006)

Ochronosis/alkaptonuria (68F, pain and stiff knee)

2° OA

Black staining from of knee from xx homogentisic Black colouration xx homogentisic acid deposits acid acid deposits into joint.