· if stage I or II left untreated, 85% collapse at 2 yrs
· metanalysis of 21 studies involving 819 hips followed an average of 3 yrs
· 74% radiologically progressed
· 76% required arthroplasty
· incidence of radiological progression related to stage (I - 35%, II -31% III - 13%)
· average time to failure was (I - 21 mths, II - 15 mths, III - 8 mths)
· not related to any aetiological factor
· not affected by degree of non weight-bearing
· preliminary investigation of
· vasoactive agents
· lipid-lowering agents
· early results show reduction in pain
· non-invasive pulsed electromagnetic-field stimulation
· experimentally shown to enhance osteogenesis and neovascularisation
· small studies show some benefit
· is experimental
· has theoretical advantages
· may be used as synergistic treatment
· further studies required
· described in 1964 by Ficat and Arlet
Rationale
· believed to have effect by
· reduction of bone marrow pressure (relieves ‘compartment syndrome’ in femoral head)
· stimulation of angiogenic and osteoblastic response (enhances ‘creeping substitution’)
· other benefits
· relieves pain
· provides tissue for diagnosis
· not suitable for post-traumatic form
Procedure
· fracture table and image intensifier
· described as part of functional evaluation
· with measurement of intraosseous pressure and venography
· not routinely performed with advent of MRI
· lateral trochanteric approach
· hollow biopsy trephine used
· 8-10 mm core removed from femoral neck and head
· from anterolateral portion
· to within 5 mm of articular surface
· 3 mm drill used to penetrate necrotic segment to subchondral bone in multiple areas
· partial wt bearing for 6 wks
Results
· great divergence of opinion
· metanalysis of 24 studies involving 1206 hips followed an average of 3 yrs
· 37% did not radiologically progress
· 33% required arthroplasty
· success related to stage (I - 84%, II - 65%, III - 47%)
· not related to any aetiological factor
· 2 studies compared core decompression with nonoperative treatment
· no collapse in 61% cf. 39%
· no arthroplasty in 75% cf. 29%
Complications
· uncommon
· include
· subtrochanteric femoral fracture
· infection
Indications
· stage I or II disease
· stage III disease where not suitable for more extensive procedures
Procedure
· can use
· direct-current stimulation
· non-invasive capacitative coupling stimulation
Results
· no clear advantage shown
· cortical bone graft inserted into defect produced by core decompression
Rationale
· provides mechanical support for articular surface during healing
Procedure
· cortical strut graft harvested from
· ilium
· fibula
· tibia
· inserted into core track
· protected weight bearing for 3-6 mths until radiographic evidence of healing
Results
· conflicting reports
· studies show success rates of 60-80% with short-term followup
· some long-term reports show 30% successful outcome
· others show 60-90% success
Disadvantages
· prolonged restricted weight bearing
Indications
· early stage III lesions
· lesions unsuccessfully treated by core decompression
Rationale
· to enhance revascularisation so that progression of necrosis halted
· vascularised grafts shown to undergo more rapid and complete incorporaion
Procedure
· considerable variability
· donor site
· ilium, fibula, greater trochanter
· muscle pedicle artery and vein used
· inferior gluteal, profunda femoris, circumflex
Results
· most studies have short term followup in small numbers of patients
· most comprehensive study by Yoo
· 81 hips followed an average of 5 yrs
· vascularised fibula anastomosed to branch of profunda femoris
· 91% of stage II or III had good or excellent clinical result
· 89% had no radiographic progression
Disadvantages
· requires considerable time and technical expertise
· postoperative restriction of weight-bearing for 6 to 12 months
Indications
· stage II or early stage III lesion
· young patient
· large lesion
Rationale
· transfers load away from necrotic area to undamaged part
· transection of bone may afford decompression
Procedure
· may be flexion, extension, varus or valgus, or rotational
· one of better-known procedures described by Sugioka
· transtrochanteric rotational osteotomy
· technically demanding
Results
· Sugioka rotation in 52 stage III hips
· 56-69% successful at an average of 5 yrs
Disadvantages
· may make subsequent THR more difficult
Indications
· stage III disease
· small lesion
· no ongoing cause for AVN
Hemiarthroplasty
· poor results
· 50% revision rate
· due to
· loosening
· protrusio acetabulae
Total hip replacement
· better results
· failure rate higher than for other diagnoses
· 25 studies show higher rate of early failure with AVN than in age-matched patients with other diagnoses
· may be explained by poor bone stock
· usually contraindicated
· 50-80% of AVN bilateral
· contralateral side may become affected some time later
· reasonable option in young, active, heavy man with unilateral disease
· eg. post-traumatic in young person
· must individualise treatment according to
· patient
· extent of lesion
· local expertise
· no collapse (stage I & II) ] core decompression
· mild involvement of femoral head ]
· young patient ]
· active patient ]
· good general health ]
· no use of steroids ]
]
]
· mild collapse (crescent sign) ] bone graft
· moderate involvement of femoral head ] osteotomy
]
]
· severe collapse or degeneration ]
· severe involvement of femoral head ]
· old patient ]
· inactive patient ]
· poor general health ]
· continued use of steroids ] total hip replacement