Clinical outcomes following reduction and pinning of lesser arc injuries without repair of the scapholunate interosseous ligament

Master Thesis


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University of Cape Town

Study Rationale: Purely ligamentous lesser arc, Mayfield grade 3 and 4, perilunate dislocations (PLD's) are uncommon. Current recommendations are for open reduction and repair of the interosseous ligaments to prevent the development of scapholunate dissociation and degeneration to a scapholunate advance collapse (SLAC) wrist. This study proposes a less invasive treatment method which includes closed reduction and pinning alone without repair of the scapholunate interosseous ligament. We propose that the majority of patients will obtain good function and pain scores and the few that develop instability may still have a reconstruction performed through a naïve surgical field. Methods: Dislocations were reduced anatomically and held with buried k-wires which were removed at 6 weeks with no specific rehabilitation protocol observed. Subjective assessment included MAYO wrist scoring system, wrist range of movement, instability and grip strength testing. Radiological measurements included scapholunate distance, scapholunate angle, radiolunate angle and osteoarthritis. Results: 10 male patients, median age of 35, were followed-up for a median of 22 months. 7 patients underwent a closed reduction and anatomical pinning while 3 underwent open reduction due to unachievable reduction by closed means. All of these patients presented at a median of 14 days after the injury occurred. None of the patients had their scapholunate ligaments repaired or reconstructed. MAYO scores included, 3 excellent scores, 2 good scores and 5 fair scores. Instability was found clinically in 1 asymptomatic patient who had a positive Watson shift test. Radiological scores include a median scapholunate distance of 2mm, a scapholunate angle of 70° and a radiolunate angle of 15°. Osteoarthritis was found in 2 patients, all of whom were asymptomatic. Discussion: Current recommendations in the literature are that PLD's should be reduced via an open surgical technique with repair of the SLIL and percutaneous pinning. However the results of this treatment strategy are not optimal and do not confer uniformly good results. We propose a closed anatomical reduction and percutaneous pinning of the PLD. Our study shows that the majority of patients will demonstrate good function and pain scores when managed this way. A smaller number of these injured wrists will go on to develop instability. However the advantage of our method over the current recommendations is that when this happens the reconstruction of the SLIL will be made easier through a naïve surgical field. Conclusion: We recommend the closed reduction and anatomical pinning of a purely ligamentous lesser arc injury. This treatment strategy yields good results at medium term follow-up and preserves the option for the reconstruction of the scapholunate interosseous ligament should instability develop.