Lakers guard Kobe Bryant has taken an unusual step to try to strengthen his ailing right knee, undergoing an innovative procedure in Germany about a month ago, according to four people familiar with the situation who were not authorized to speak publicly.

The treatment is a derivation of platelet-rich plasma therapy. PRP procedures are less invasive than many surgeries involving the knee and are viewed as either an emerging solution to knee problems or a financial gamble on unproven science.

Bryant, who turns 33 next month, has been bothered in recent seasons by an arthritic joint in his right knee. He has undergone three other knee procedures since 2003, including surgery last July to remove unspecified loose bodies.

He sat out an overwhelming majority of the Lakers' practices this past season and saw his scoring, shooting percentage and minutes decrease in his 15th NBA season.