Medial Compartment Osteoarthritis with ACL instability




This x-ray demonstrates mild medial compartment osteoarthritis of the knee associated with anterior cruciate ligament deficiency. There is a significant varus alignment present in both knees.

There is not much question that in this situation, a HTO and should be the procedure of choice. Similarly, with the photo below the most likely treatment would be an osteotomy or total joint.






The best treatment for the patient over 55 years of age with severe medial compartment osteoarthritis is a joint replacement. The decision of whether to do a total replacement or uni-compartment replacement is the surgeons decision, based on his past experience.


In order to sort of the problem of the ligament deficiency and osteoarthritis the patient should be evaluated clinically.

  • History

The history of giving way suggests the anterior cruciate ligament deficiency; whereas the history of activity related medial pain suggests the arthritis is the main concern.

  • Physical Examination

The positive Lachman and pivot shift tests are indicative of the cruciate laxity. The 10* lack of extension, and the absence of the pivot shift test points more to the osteoarthritic component. Remember to look at the patient, the degree of varus alignment should be evaluated when standing.

This is a moderately severe varus, and an osteotomy should be considered.





  • Imaging

The standing x-rays in extension and 30* tunnel view will show the degree of medial compartment narrowing. The earliest sign of narrowing occurs in the tunnel view. If this is the only view that the osteoarthritic change is demonstrated, then the ligament reconstruction alone is a good choice.

  • Arthroscopic evaluation

The arthroscope can document the degree of chondral damage better than x-ray imaging. The lateral compartment should be free of degenerative changes if you are contemplating an osteotomy.

Treatment options for this problem are:

  • Conservative
    • Physio-therapy to increase the range of motion , and strength the muscles.
    • Unloader Generation 2 brace for recreational activities such as golf.
    • Anti-inflammatory medication

  • Operative
    • Arthroscopic debridement
    • Ligament reconstruction alone
    • High tibial osteotomy alone
    • Combined ligament reconstruction and high tibial osteotomy Unicompartment replacement
    • Total knee replacement


  • The difficult question is, whether to do ligament reconstruction or high tibial osteotomy or the combined procedure.
    • This should be an individual decision based on the history, the examination, the standing x-rays, and the arthroscopic evaluation.