Introduction

Medial patella luxation (MPL) is an orthopaedic condition that commonly affects small and occasionally large breed dogs. The luxation is associated with a number of skeletal abnormalities and many surgical procedures have been suggested to treat the condition. The purpose of this study was to assess the response to performing a tibial tuberosity transposition alone after arthroscopic examination of the stifle.

Materials and Methods

The medical records of dogs suffering MPL in isolation, treated by the author between December 2004 and September 2007 were reviewed.

Surgical treatment consisted of a standard arthroscopic examination of the stifle to assess patella position and pathology and a tibial tuberosity transposition. Exercise was restricted until radiological union was demonstrated 4 weeks post operatively. Analgesia was provided with meloxicam.

Results

The study included 15 dogs (21 stifles). Two bilateral cases were treated in one procedure. Follow up ranged from one month to three years.

There were five Yorkshire terriers and two Staffordshire Bull terriers the rest were other small breeds. Ages ranged from one to eight years. There were 11 left and 10 right stifles and the luxation grade ranged from 1/₄ to 3/₄ on presentation. There was erosion of the patella and or medial trochlear ridge in six stifles. Four dogs had pin and tension band wire fixation (including both single procedure, bilateral surgeries) the others had pin fixation alone. Minor complications included three cases (4 stifles) in which the implants broke but did not require removal and two cases (two stifles) in which the implants required removal. There were four cases of major complication in which three individuals (five stifles) had persistence of the luxation and one case that required revision surgery for an unstable osteotomy. All four cases of major complication had patella alta.

Conclusions

MPL may be successfully addressed by arthroscopic stifle examination and tibial tuberosity transposition alone. Patella alta on presentation may cause complications including recurrence of MPL.