- Congenital Synostosis:
-
discussion:
- occurs due to a defect in longitudinal segmentation at the 7th week of development;
- autosomal dominant inheritance in some cases but often occurs sporatically;
- bilateral in 60% (most common in males);
- proximal 1/3 of forearm is most common site of bony union, and the forearm is pronated (avg 30 deg);
-
non operative treatment:
- patients with a unilateral deformity or with a bilateral deformity & minimal
pronation do not need surgery;
- majority of patients w/ bilateral osseous radioulnar synostosis function
adequately despite forearm position;
-
surgical treatment:
- surgery is rarely indicated for this condition, except for severe pronation deformities (more
60 deg of pronation)
- resection and interposition procedures fail, and the bridge regrows;
- in pts w/ severe bilateral hyperpronation, osteotomy of nondominant
extremity, to create supination, is indicated.
- derotational osteotomy through the area of synostosis is recommended,
placing one side in 10 to 20 degrees of pronation and the other
forearm in a neutral position or slight supination for function;
- references:
Congenital proximal radio-ulnar synostosis. Natural history and
functional assessment.
Congenital Proximal Radioulnar Synostosis: Treatment with the Ilizarov Method.
Bolano, L.E. Journal of Hand Surg 19A: 977-978, 1994.
Congenital radioulnar synostosis.
Simmons, B.P.; Southmayd, W.W.; Riseborough, E.J.
Journal of Hand Surg Vol 8: 829-838, 1983.
- Traumatic Synostosis:
- see
discussion of hetertopic ossification and
hetertopic ossification of the elbow;
-
discussion:
- may arise from posterior frx dislocation of the elbow, Monteggia frx dislocation, traumatic rupture
of the distal triceps, both bones forearm frx, or from isolated radial head frx;
- often these patients have undergone previous surgery;
- exam findings: absence of forearm pronation and supination;
- in some patients the hetertopic ossification will extend into the elbow joint which will
limit flexion;
-
management:
- traumatic synostosis is amenable to surgical excision;
-
timing of excision:
- traditionally, it has been recommended that hetertopic bone not be excised until there
has been maturation (as judge by bone scan or
serum alk phos);
- this has been challenged by Jupiter et al 1998, who noted no ill effects from excision of
synostosis at 6-12 months post injury;
- surgical approach:
- often the synostosis is amenable to excsion via a posterior approach;
- w/ proximal synostosis, the ECU and the supinator are elevated off the ulna, which
allows exposure of the synostosis and the radius;
- w/ proximal synostosis, consider
anterior transposition of the ulnar nerve;
- denuded bony surfaces are covered w/ a thin layer of bone wax at the end of the case;
- postoperative care:
- in the report by Jupiter el al 1998, neither postoperative radiation nor indomethacin was
considered essential to prevent recurrence;
- head injury patients may be at higher risk for recurrence, and therefore, they may
require XRT or NSAIDS;
Operative treatment of post traumatic proximal radioulnar synostosis.
JB Jupiter and D. Ring.
JBJS Vol 80-A. No 2. Feb 1988. p 248.
Post traumatic radioulnar synostosis.
R. Breit.
CORR. Vol 174. 1983. p 149-152.
Post traumatic proximal radio-ulnar synostosis.
JM Failla et al.
JBJS Vol 71-A. Sep 1989. p 1208-1213.
Cross union complicating fracture of the forearm. Part I: adults.
KG Vince and JE Miller.
JBJS. Vol 69-A. Jun 1987. p 640-653.
Treatment of posttraumatic radioulnar synostosis with excision and low dose radiation;
RA Abrams et al.
J. Hand Surg. Vol 18-A. 1993. p 703-707.
Radioulnar synostosis.
K Sachar et al.
Hand Clinics. Vol 10. 1994. p 399-404.
Treatment of traumatic radioulnar synostosis by excision and postoperative low dose irradiation.
JP Cullen et al.
J. Hand Surg. Vol 19-A. 1994. p 394-401.
