An olecranon stress fracture and a persistence of the olecranon physis are seen in adolescent baseball players associated with valgus extension overload. They were often unable to return to sports early, however, because of cases of delayed union or refracture. And many doctors suggested the necessity of surgery. Extracorporeal Shock Wave Therapy (ESWT) has been reported to be effective in the treatment of stress fracture. However, there are no studies regarding ESWT exclusively for olecranon stress fracture in baseball players. The purpose of this study is to report clinical results of olecranon fracture in baseball players that were treated with ESWT.
13 baseball players (13 elbows) who were treated with ESWT were included in this study. All subjects were competitive level athletes, and all patients were male. All affected sides was their throwing side. The mean age was 15 (13-21). Exclusion criteria was olecranon tip fracture cases. The mean follow up period was 9 months. They played in the following positions: pitchers (8), outfielders (3), catcher (1) and infielder (1). Each subject received 1 to 2 times ESWT. Maximum energy flux density (EFD) ranged from 0.07 to 0.36mJ/mm2. At each session, subjects received 3000 to 5000 shocks. All of them received physiotherapy focusing on eccentric loading exercises along with ESWT. Our primary assessment was to analyze clinical results, including, return to competition, recurrence, period between presentation and ESWT. Our secondary assessment was to analyze the period until bone union and bone union rate between olecranon stress fracture cases and persistence of the olecranon physis cases in plane radiographs.
All patients returned to competition. In the season cases(8 patients), their return to competition time is 6.1 weeks on average (4-9). One patient returned to sport as the infielder from the pitcher. One of them had recurrence of symptoms 3 months after taking ESWT, but he returned to competition after the second ESWT and no recurrence. The complete competition return rate was 86%. In the off-season cases (5 patients), those return to competition time is at 16.4 weeks on average (8-28). Two of them had recurrence of symptoms 3 months and 52 months after taking ESWT, but they returned to competition after the second ESWT and no recurrence. The complete competition return rate was 100%. The mean period between presentation and initiation of ESWT was 2.9 months (0-9) in the season, 4.4 months (2-7) in the off-season. In the olecranon stress fracture cases, bone union was seen in 6 cases, improvement was seen in 2 cases, and no change was seen in 1 case. In persistence of the olecranon physis cases, closed physis was seen in 2 cases, improvement was seen in 2 cases, no change was 1 case. The mean period until bone union was 8.6 months (2.5-20) in the olecranon stress fracture cases and 19.8 month (10- 27) in persistence of the olecranon physis cases.
This study indicates ESWT is a safe and viable option for the treatment of an olecranon stress fracture and a persistence of the olecranon physis in adolescent baseball players. ESWT for those patients was effective for pain relief and shortened the period of return to sports. It also indicates that bone union of the olecranon stress fracture was promoted after several sessions of ESWT, and that closing of the olecranon physis might not be affected after several sessions of ESWT.