Memphis Grizzlies’ Tony Allen (9) defends Los Angeles Lakers’ Kobe Bryant (24) during the first half of an NBA basketball game in Memphis, Tenn., Tuesday, Dec. 17, 2013. (AP Photo/Danny Johnston)

Below is a Q&A with Dr. William Long, orthopedic surgeon and medical director of the Orthopaedic Computer Surgery Institute at Good Samaritan Hospital in Los Angeles on Kobe Bryant’s lateral tibial plateau of his knee. The Lakers expect Bryant to sit out for about the next six weeks. Dr. Long spoke in general terms about the injury since he hasn’t treated Bryant or seen his medical records.

Can you describe for me what the injury is involving a lateral tibial plateau in a knee?

A tibial plateau is worrisome because it involves a cartilage surface. The bone holds up the cartilage on the outside of the knee. That’s a different category than all other fractures. You could break the bone in the middle of the shaft, and when it heals it could be as strong as it ever was. But if you hurt the joint, it can ruin the knee. I obviously haven’t seen the x-rays, but there are different patterns. There’s a crack where there’s a tiny crack and the joint surface is relatively underserved. If you can punch a hole in the middle of the joint, that’s one of the worst ones. If it’s displaced, there won’t be any optimistic predictions. If it’s nondisplaced, then you hear six weeks before you start to rehab. Usually, that’s a minimum of three months. But I’m obviously saying that not seeing the patient and the x-rays. I’m just talking about the mechanism of the injury.

Can this kind of injury ever be related to an Achilles injury?

Yes, it can be. Indirectly. But absolutely, it can be related. When you can’t bear weight fully on a limb, you lose bone mass. Even if you can start to run on an Achilles, there’s a long period of time where you’re not doing high impact activities on that limb. So you lose bone mass. It doesn’t return instantly. Rehab in the past was always considered a year to return. But he was on an accelerated rehab schedule. We’re seeing it before our eyes with these top players with Derrick Rose, Kobe, Robert Griffin. They return very early. They get injuries that don’t seem to be related. But they could be absolutely related.

It’s plausible you don’t have all your bone mass restored even if you have an Achilles that is healed and is strong enough to take moderate impact. But the bone is always weaker than before then time you get injured. So that makes it more likely to get injured or break. Therefore, contact that would’ve normally just resulted in a bruise can become a fracture.

What’s the rehab that usually entails for a lateral tibial plateau of a knee?

It depends. If the joint is interrupted, all the rehab is in jeopardy. If there’s a tiny crack that doesn’t interrupt the smooth surface of the joint, then at six weeks you can put full weight on a knee and put it through range of motion. That’s if you have the most benign fracture pattern imaginable. If it becomes any more than that, then it gets worse. So this isn’t a rosy picture.

Kobe told us he thought he originally hyperextended his knee and he kept playing through that. Can playing through that provide additional damage to the knee?

Most of big damage is already done on contact. You bear 60 percent of the weight on the inside of the knee and 40 percent on the outside of the knee when you’re walking normally. If a break isn’t completely out of place, you can get away with bearing weight. You can bear most of the weight on the rest of the knee. No serious additional damage can happen afterwards. The real damage happens with the first impact when you first break the bone. On subsequent impact, you can’t put much pressure on the joint anyway.

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