- See:
-
Proximal Pole Frx:
-
Bone Grafting of Scaphoid Non Unions:
-
Scaphoid Nonunions:
- Radiographs:
- need to determine whether there is
AVN of scaphoid:
- classic signs of AVN include:
- ground-glass appearance or increased bone density;
- loss of trabecular pattern;
- cystic changes;
- subchondral collapse and fragmentation;
- some authors have questioned whether or not radiographic appearance of proximal pole accurately correlates with AVN;
- in majority of these cases, the proximal fragment appears relatively dense radiographically, indicating some degree of ischemia;
- this is accentuated after wrist has been immobilized as the rest of the carpi become osteoporotic;
- AVN of scaphoid is often difficult to diagnose radiographically and therefore it is usually necessary to assess vascularity
of the proximal pole at the time of surgery;
- absence of punctate bleeding in the proximal fragment (after debridement) is the best indicator of AVN;
- Pre-Operative Considerations:
- these fracture can be technically difficult to manage and may carry a poor overall prognosis;
- there is seldom any significant carpal deformity or collapse, so that cancellous bone grafting alone is normally sufficient;
- care should be taken with curettage or resection of pseudarthrosis to ensure that there remains sufficient bone
in the proximal fragment to allow for satisfactory internal fixation;
- proximal fragment nearly always appears somewhat unhealthy at operation
- occasionally fragment is soft and necrotic, in which case reconstruction is not possible;
- more commonly, however, the bone is hard and sclerotic;
- if proximal pole demonstrates punctate bleeding at the time of surgery then expected rate of healing is over 90%;
- if there appears to be some possibility of revascularization, bone grafting and screw fixation should always be attempted;
- radial styloidectomy:
- may be contra-indicated in established scaphoid non union since it may further destabilize the wrist joint;
-
Non-union of the scaphoid. Revascularization of the proximal pole with implantatin of a vascular bundle and bone-grafting.
- involves iliac corticocancellous grafting and implantation of second dorsal metacarpal artery into the proximal scaphoid;
- surgical approach:
- volar approach is made only if there has been a previous approach on that side of the wrist;
- dorsal approach to the scaphoid involves longitudinal incision from Lister's to the base of the thumb CMC joint (just ulnar to EPL tendon);
- dissection thru the subQ tissues (avoiding sensory nerves) and develop the interval between the ECRL and EPL;
- incise the wrist capsule overlying the scaphoid;
- debridement of non-union;
- sharply remove all fibrous tissue and sclerotic bone surfaces;
- assessment of vascularity;
- look for punctate bleeding points (w/ tourniquet elevated or w/ tourniquet released when there is minimal bleeding);
- when vascularity is present, implantation of the second dorsal metacarpal artery will not be present (and only bone grafting is necessary);
- bone grafting:
- using a burr or currett, create a cigar shaped hole 5 mm in diameter in the proximal fragment and a trapezoidal shaped notch
in the distal fragment to accomodate the graft (and to help lock it in place);
- insert an appropriately sized corticocancellous bone graft w/ the cortical side pointing dorsally;
- K wire Fixation:
- 1-2 K wires are inserted along the longitudinal axis of the scaphoid, parallel to the graft;
- arterial implantation:
- implantation site lies slightly ulnar to the center of the proximal pole;
- drill hole is made in a dorsal to plantar direction;
- second metacarpal artery is mobilized and is brought thru the drill hole;
- the wrist capsule is left open where it is adjacent to the artery;
Non-union of the scaphoid. Revascularization of the proximal pole with implantatin of a vascular bundle and bone-grafting.
Dorsal approach to scaphoid nonunion.
Retrograde Herbert screw fixation for treatment of proximal pole scaphoid nonunions;
Treatment of selected patients with an ununited fracture of the proximal part of the scaphoid by excision of the fragment and insertion of a carved silicone-rubber spacer.
Prognostic factors in the treatment of carpal scaphoid non unions. F. Schuind MD et al. J. Hand Surgery. Vol 24-A. No 4. Jul 1999. p 762.
The effect of avascular necrosis on Russe bone grafting for scaphoid non-union. Green, DP. J. Hand Surg. Vol 10-A. 1985. p 597-605.
Treatment of scaphoid nonunions: Quantitative meta-analysis of the literature Gregory A. Merrell, MD. J Hand Surg 2002;27A:685–691.
Surgical Treatment of Nonunion and Avascular Necrosis of the Proximal Part of the Scaphoid in Adolescents
