A new variant of scaphoid reconstruction: Treatment of scaphoid non-union with avascular bone interponate and high compression screw (Synthes®)

Scaphoid fractures as frequently overseen injuries often result in scaphoid non-unions, that need to be treated to prevent carpal collapse and secondary cartilage damage. Vital bone tissue and compression of fracture and bone graft ends seem to be crucial in for ossification and final bone healing. In the present study we compare our results using a high compression screw (HCS Synthes(®)) to results in the literature using different kinds of internal fixation including compression screws of various types. We present 22 patients with scaphoid non-unions treated with a bone graft and a HCS Synthes(®). We evaluated our post-operative results. The Manchester-Modified Disability of the Shoulder, Arm and Hand-Score (M-Dash) imposed with an average of 29.8 points (MD=29 / SD=9.46 / MIN=18 / MAX=48). None of the re-evaluated patients sorrowed for pain in rest. Five patients stated pain (ranging from 4 to 8 on numeric analogue scale) after heavy burden (e.g. boxing, weight lifting).In exploring the range of motion of the operated hand we deliver the following results: dorsal extension: average 72.73° (MD=80° / SD=17.23° / MIN=30° / MAX=85°), flexion: average 73.64° (MD=80° / SD=8.97° / MIN=60° / MAX=80°), ulnar deviation: average 39.09°, (MD=40° / SD=2.02° / MIN=35° / MAX=40°), radial deviation: average 29.09°, (MD=30° / SD=3.01° / MIN=20° / MAX=30°). Additionally a performance testing was conducted: fist clenching sign: complete without pain in 100%, pinch grip: complete in 100%, moderate pain in n=1 (8.33%), opposition digitus manus I-V complete in 100%, moderate pain n=2 (16.67%). Three patients with persisting fracture gap had a scaphoid bone fractured in the proximal third; one patient even with a very small proximal fragment. One persisting non-union was localized in the middle third (period between injury and operation = 5 years). In conclusion, our patients showed better healing rates compared to results presented in the literature. Non-unions localized in the proximal third of the scaphoid did not seem to benefit using this technique.