Andrew Bynum underwent arthroscopic surgery to mend torn meniscus in his right knee Wednesday. The Lakers said they expect the 7-foot center to be available on a limited basis during training camp and to be fully recovered by the start of the regular season. Training camp begins Sept. 25, with the regular season set to begin in late October. (The schedule will be released next month). David Altchek, Bynum’s personal physician, performed the surgery in New York. Bynum was injured during Game 6 of the Lakers’ opening-round playoff victory over the Oklahoma City Thunder in April. He did not miss a playoff game despite having limited strength in his knee and he averaged 8.6 points and 6.9 rebounds in 24.4 minutes. He averaged a career-best 15 points on 57 percent shooting in 65 regular-season games. He also averaged 8.3 rebounds in 30.4 minutes.