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What’s New in Knee Surgery

The following article is written by Andrew Merritt, MD.

This month in KSSTA, Kim et al. investigate the outcomes of ACL surgery in patients with hyperlaxity. Hyperlaxity is defined by having joints that are “extra-mobile” and present sometimes as “double-jointed.” Most commonly in young females, we frequently see athletes with hyperlaxity that sustain injuries to their anterior cruciate ligament (ACL). This is one of our most challenging groups of patients when treating knee injuries.

It is common for young adolescent athletes, especially females, to have hyperlaxity of multiple joints and this affects the outcome of ACL reconstruction. Multiple studies have demonstrated a worse clinical outcome after ACL reconstruction when the patient has generalized laxity.

The cause for these outcomes is clear. In the knee, the ACL is one of the stabilizing ligaments, but the ACL needs help from other structures of the knee that are loose when a patient has laxity. The knee depends on multiple other structures including the meniscus, joint capsule, muscles, and other ligaments. If people have hyperlaxity, these other structures often do not assist the ACL in stabilization of the knee. As a result, while the ACL reconstruction may be perfect, there remains some looseness in the knee and the outcomes are worse.

The study aimed to evaluate if the choice of graft for reconstruction affects the outcomes in this challenging patient population. Two of the more common graft choices are bone-patellar tendon-bone (BTB) and hamstring tendons. This study found that BTB grafts had superior outcomes at both 2-years and 5-years post-op. Additionally, the knees were tighter when the ACL was tested suggesting that the ACL was able to restore more normal motion and stability.

This study has mirrored my own experience. I have switched exclusively to BTB autograft ACL reconstructions for athletic patients with hyperlaxity or hypermobility of their joints. This study has verified that these patients have better clinical outcomes and better return to sports with this procedure then with hamstring autograft.

If you have an ACL injury, please discuss what type of graft is best for your knee. If you are loose-jointed or double-jointed, make sure the surgeon is comfortable with the BTB ACL reconstruction. As always, I would be happy to be involved in your care and please contact us if you would like a consultation.

Andrew Merritt, MD is an orthopedic surgeon specializing in sports injuries of the knee. He treats athletes of all ages and provides team coverage for many area high schools. For more information about ACL surgery, meniscectomy or knee injuries, please contact Proliance Orthopedic Associates at 425.656.5060for a consultation.



4011 Talbot Rd S #300
Renton, WA 98055

Phone: 425.656.5060
Fax: 425.656.5047


27005 168th Pl SE #201
Covington, WA 98042

Phone: 253.630.3660
Fax: 253.631.1591

Maple Valley

24060 SE Kent Kangley Rd,
Maple Valley, WA 98038

Phone: 425.358.7708
Fax: 425.656.5047

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