The most recent information on Marcus Lattimore's knee injury is that he sustained a knee dislocation without fracture. This is a devastating injury for a high level athlete and likely jeopardizes his chances to play professionally. Knee dislocations are a complex injury requiring precise diagnosis of which structures are injured and subsequent surgical procedure/procedures to reconstruct and repair the involved structures. By definition, a knee dislocation involves at least 3 of the 4 main ligaments in the knee. The injuries sustained in a knee dislocation can include the cruciate (ACL, PCL) and collateral ligaments (MCL, LCL), posterolateral corner, menisci, articular cartilage, fractures, and vascular injuries just to name a few. Most of the the research on these injuries involve significant traumatic injuries such as automobile accidents. There are few papers on return to sports following knee dislocation.
Hirschmann MT published an article in 2010 in the American Journal of Sports Medicine titled "Surgical Treatment of the Complex Bicruciate Knee Ligament Injuries in Elite Athletes: What Long-term Outcome Can we Expect?" The results showed that only 8 of 24 athletes returned to their pre-injury level of sports activity. This is dramatically different from isolated ACL injuries where almost all athletes return to their pre-injury level of play. The athletes that had the best outcomes had early, open, complete single stage surgery. Luckily Marcus will have the best care possible increasing his odds for a full recovery. I am hoping that he proves the statistics wrong with a return to his football career.
Combined ACL and MCL injuries can be difficult to treat, especially in the high level athlete. Partial MCL injuries (grade 1 & 2) will heal and standard ACL reconstruction can be performed without significant risk of complications. Complete MCL injuries (grade 3) need to be repaired or reconstructed to regain valgus stability. There is debate on the timing of these surgeries. Should the ACL reconstruction and MCL repair/reconstruction be performed at the same time or done as two separate procedures?
The results of a recent study by Grant in the journal of Arthroscopy showed that "Outcomes were better if the ACL was reconstructed and reconstruction was delayed to allow a return of knee range of motion. In many cases, this delay may allow the MCL to heal. MCL repair or reconstruction may be required if valgus instability remains after an appropriate rehabilitation period." It concludes that "ACL reconstruction should be performed in a subacute time frame once full motion has returned. Valgus instability should be assessed at that time and MCL repair or reconstruction performed in those patients with persistent valgus instability."
Partial ACL injuries pose a problem of their own. Is the knee stable enough to return to high level sports without ACL reconstruction? Patients that are able to return sports without surgery are considered "copers." In 2011 Tjoumakaris published an article in the American Journal of Orthopedics, "Partial Tears of the Anterior Cruciate Ligament: Diagnosis and Treatment." The article states that the "Natural history studies following patients with these injuries have demonstrated that fewer than 50% of patients return to their preinjury activity level. Several studies have also documented that progression to complete rupture is a common outcome for patients who want to return to an active lifestyle."
Although the research isn't conclusive, the evidence supports subacute ACL reconstruction with concurrent MCL repair/reconstruction if valgus laxity persists. In the case of partial ACL injuries, reconstruction may be the best option due to their high likelihood of progression to complete rupture and the poor rate of return to pre-injury levels of sports participation.