Alone, the letters "a. c. l." might not mean much while completing a crossword puzzle. However to a competitive athlete the term "ACL" might represent a significant knee injury that can cause heartache and disrupt a promising career. Case in point: Al Harrington of the Indiana Pacers.

Al was on his way to a "career year" with the Pacers when he injured his knee, trying to fight through a screen in the fourth quarter of the Pacers' 98-94 loss to the Celtics on Jan. 23. He tore the Anterior Cruciate Ligament (ACL) in his left knee and underwent season ending reconstruction surgery.

Figure 1: Knee Model with ACL

Figure 2: MRI of Normal ACL

Figure 3: MRI of Torn ACL
(Photos by

The ACL is very critical to an athlete because it provides so much stability to the knee. It is deeply embedded in the knee joint and connects the femur (the thigh bone) to the tibia (the shin bone). (Figure 1) This ligament prevents the knee joint from moving to far forward and back and helps absorb many of the rotational forces the knee encounters. When it is damaged, the athlete will feel a sense of instability with activities of every day life as well as athletic activity. If not corrected, this instability can compromise an athlete's ability as well as cause problems later in life.

When Al sustained his injury, he was evaluated by the Pacers' medical staff in order to establish a preliminary diagnosis. The following day, he had an MRI to make the final determination. The MRI is extremely sensitive to torn ligaments such as the ACL and is a valuable tool in diagnosing injuries such as this. (Figures 2 & 3) Once the extent of all of the damage was determined, the next step is the decision as to how to take care of the problem. In this situation, ACL reconstruction surgery was chosen.

Al had the surgical procedure performed by Dr. Sandy Kunkel, Orthopedic Team Physician of the Pacers. To be successful at this surgery, Dr. Kunkel needs to be somewhat of a carpenter and construction engineer as well as a skilled surgeon. The ACL reconstruction involves removing a long portion of the patellar tendon, which is located at the bottom of the kneecap. This graft is surgically attached to the tibia at one end and the femur at the other and essentially replaces the damaged ligament. There are precise points that the surgeon needs to place the graft at in order to maximize the efficiency of the new ligament, and minimize complications from the surgery.

“I was very pleased with the result of the surgery,” Kunkel said. “We reconstructed his ACL and repaired cartilage damage. We expect Al to make a full recovery. He is out for the season, but we are extremely optimistic about his future. We expect him to be ready for training camp.”

Rehabilitation of the ACL reconstruction is also critical, and it starts in the recovery room immediately after surgery. A machine was placed under Al's knee that would move it up and down for hours. This early motion is designed to reduce the chances of knee joint stiffness down the road. As time progresses, Al will spend a great deal of time in rehab under the watchful eyes of athletic trainer David Craig and the Pacers Medical staff. He will regain his flexibility, strength, and fitness through many of the usual rehab modalities. Ultimately, he will begin light shooting and court drills to re-train his leg for playing basketball.

Al has joined an exclusive club of young NBA players who have had ACL reconstruction, such as Bonzi Wells and Baron Davis (who tore his in college). These players have come back to excel without further knee problems. Through hard work, Al will be able to resume his career where it was cut short this season.

Tom Abdenour in his 15th season as the athletic trainer for the Warriors. He spent his 2000 offseason serving as the athletic trainer for the gold medal-winning USA Men's Basketball Team at the Summer Olympics in Sydney, Australia. He also stays involved with the community as a member of the NBA's National All-Star Reading Team -- part of the Read to Achieve program.

Abdenour is hosting's Gonna Make You Sweat: NBA Health & Conditioning section by answering fan questions and providing his insight and expertise on a series of fitness and rehabilitation issues.