Replacement options to relieve pain and help restore function

When the knee is beyond repair, replacement options may be needed. 

Emerging Meniscal Bio-technology

Investigators are continuing to evaluate the role of collagen or other material to serve as a bridge, allowing the body's own healing/repair mechanism to re-establish the function of the meniscus.  Currently, the only scaffold that has US FDA approval is the Collagen Meniscal Scaffold (CMI®). While it is fully FDA approved and the reported outcomes are promising, most insurance companies do not pay for CMI surgery as they consider it “experimental/investigational”. Although not yet available in the US, in Europe there is a polyurethane “honey comb” scaffold (Actifit® by Orteq®) that appears to produce good clinical outcomes as reported in a 2-year study by Verdonk.

In the United States, basic science studies have been conducted on other alternatives to meniscus regeneration. Dr. Farr was a key investigator in a clinical study evaluating if injection of an adult mesenchymal stem cells could regrow a meniscus. While the study demonstrated some regrowth of meniscal tissue, it did not restore the function of the meniscus ( However, the study did show that patients with early osteoarthritis symptoms had a decrease in their symptoms during the two years of the study.

Articular Cartilage - Established Arthritis

Unfortunately, many patients have articular cartilage damage that is beyond repair, regeneration or restoration. They often suffer for many years with arthritis that limits daily living activities. For these patients, our knee surgeons have replacement options to relieve pain, help restore function and help with pain management.

Unicompartmental Knee Replacement and Patellofemoral Replacement

This procedure replaces only the damaged compartment of the knee with metal and plastic, leaving the remaining joint intact for a more "natural feel." There is less blood loss than with a total knee replacement and the majority of patients return home the morning after surgery.

Total Knee Replacement

If there is extensive damage which precludes the use of the above procedures, then the entire knee joint surface is replaced with artificial components, allowing most patients to return to activities pain-free. This procedure can be performed by one of Dr. Farr’s OrthoIndy arthroplasty partners.


Ligaments connect bones and stabilize their position. Loss of ligament function allows instability. The instability is not only a functional problem, but also could lead to abnormal stress on cartilage repair/restoration. Therefore, ligament reconstruction is often performed before or at the same time as the cartilage surgery.

ACL (Anterior Cruciate Ligament) Reconstruction

Over the past 3 decades, ACL surgery has been further refined, yet key features of the procedure have remained constant: replacement using the “footprints” of the native ACL and using a strong graft. Autograft (patients own tissue) is more reliable than cadaver grafts and patellar tendon grafts have a much lower tear rate than hamstring grafts and thus is the most common graft used by Dr. Farr. With regional anesthetics and arthroscopically assisted techniques, the procedure is performed as an outpatient and allows early rehabilitation.

MPFL (Medial Patellofemoral Ligament)

Recurrent patellar instability (RPI) is a disabling problem. The underlying problems that allow the kneecap to dislocate are unique to each patient. One common factor with RPI is the ligament tear that checks-reins the kneecap called the Medial Patellofemoral Ligament or MPFL. Like ACL reconstruction, the key to a good result is placing the MPFL graft anatomically. 

However, as there is a rich blood supply for the graft, allograft (cadaver tissue) is equally effective as autograft and avoids the harvesting of the patient's own tissues. Note that when treating recurrent kneecap instability, a comprehensive preoperative evaluation is performed to identify other contributing factors to the instability and then correction of these factors may be performed at the same time as MPFL reconstruction.