OBJECTIVE To present the results of various treatment modalities based on injury grade of radial collateral ligament (RCL) injuries to the index metacarpophalangeal (MP) joint. METHODS Fourteen patients were evaluated (4 male, 10 female) with RCL injuries to the index MP joint. We defined injuries as Grade 1 (tenderness over RCL, no instability), grade 2 (laxity compared to the contralateral digit with a definite endpoint), or grade 3 (laxity without endpoint). Early presentation is defined as less than four weeks and late greater than four weeks. RESULTS The average follow up was 24 months. Grade I-II injuries seen early (4 patients) treated with 4-6 weeks splinting had excellent results (normal ROM, stable pinch, pain free). There were no Grade I-II injuries seen late. Of Grade III injuries seen early (2 patients), attempted treatment in a removable splint was unsuccessful secondary to patient noncompliance; subsequently requiring primary repair of the collateral ligament which resulted in good outcomes. No Grade III injury seen early had attempted treatment in a cast. Eight patients presented late with Grade III injuries (4 elected for surgical intervention, 4 for nonsurgical management) and all had fair or poor outcomes. CONCLUSIONS The significance of this injury remains underestimated and requires a high index of suspicion. Stable injuries seen early should be treated with prompt immobilization. Casting may be more effective than a removable splint. Grade III injuries seen early could possibly be treated with cast immobilization though close follow up is mandatory as surgical repair may be necessary in the high demand hand. All Grade III injuries treated late yielded fair to poor results requiring tendon reconstruction or fusion with significant alteration in hand function.