American Society for Peripheral Nerve

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Treatment of Scaholunate Instability with Internal Screw fixation
Christopher M. Jones, MD; Jaehon Kim, MD; Michael S. Murphy, MD
Curtis National Hand Center, Union Memorial Hospital, Baltimore, MD

Hypothesis: As one of the most common types of carpal instability, scapholunate dissociation remains a challenging problem without a consistently successful solution. The overall goal of surgery is to preserve normal anatomic alignment of the carpus, therefore preventing progressive degenerative arthrosis. We hypothesize that the reduction and association of the scaphoid and lunate with internal screw fixation is a safe and efficacious technique for scapholunate dissociation.

Methods: Between January 2003 and February 2013, six surgeons from one large hand referral center performed screw fixation for 30 patients with scapholunate instability. A single cannulated screw was used to maintain anatomic reduction of the scaphoid to the lunate in this reconstruction technique. Soft tissue augmentation varied depending on surgeons. Preoperative physical exam findings were reviewed, as well as type of screw implanted. Patients were evaluated for post-operative range of motion, and whether their hardware was subsequently removed or retained.

Results: Of the 30 patients, there were 22 males (73%) and 8 females (27%) who underwent internal screw fixation for scapholunate instability. Their mean age was 41.6 years (range 22-62 years) and 21 of the patients injured their dominant hand (70%). The average time from injury to surgical intervention was 25 weeks. The mean post-operative follow-up for this cohort was 38 weeks (range 8-152 weeks). Among those patients available for physical exam, average arc of motion was 89 degrees with flexion and extension, independent of screw type. There were 9 headed cannulated screws and 21 headless screws inserted. Of the 21 headless compression screws, 9 were subsequently removed (43%) and 7 of the 9 headed screws were removed (78%). Overall 16 out of 30 screws (58%) were eventually removed. All of the 7 headed screws, and 6 of the 9 headless screws were removed routinely as a planned staged procedure. The remaining 3 headless screws were removed secondary to implant loosening or symptomatic hardware. Only 1 patient (3%) required revision surgery for wrist arthrodesis.


  1. Reduction and association of the scaphoid and lunate with internal screw fixation is a safe and effective technique for scapholunate dissociation.
  2. There is no significant difference in post-operative range of motion between patients with a retained scapholunate screw and those who had their screw removed

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