Mediman14:
Submit claims for each.
The labrum is the rim of cartilage surrounding the hip joint, attached to the acetabulum. While it's one "area", an anterior and a posterior tear relate to two "slightly separate" areas, and can be considered as two separate conditions. Mostly, because an anterior tear may be present, without the presence of a posterior tear, and vice versa, and they may have separate mechanisms of injury.
The osteoarthritis (OA) may have entirely different causes. It may be wear and tear over the years of your service (i.e., cumulative joint trauma), or a direct injury which aggravated the development of OA, such as whatever may have caused your labral tears. It could also be the result of your labral tears, so you could be looking at a consequential claim.
In any case, apply for the two new conditions. Ensure you have medical opinions, etc. to support your claims.
Just because you have been approved for one does not however guarantee you will be granted entitlement for the other. To take the knee for example, as opposed to such a small area as the labrum. Let's say you tear your ACL playing base hockey. A few years later, ACL is all good and healed, but you tear your MCL moving furniture at home. One is related to service, the other is not. The same might be determined for your anterior/posterior tears.
A quick point...osteoarthritis causes pain, but osteoarthritis is a medical condition, whereas pain is symptom...symptoms are not pensionable.