Prospective study wins 2011 Best Poster Award at AAOS Annual Meeting
The 2011 Best Poster Award went to a prospective study examining the link between the loss of normal knee range of motion (ROM) after anterior cruciate ligament reconstruction (ACLR) and the incidence of arthritic changes observed on radiographs. The authors found that patients who were able to obtain and maintain normal knee motion had a lower incidence of such changes than patients who lost knee motion.
Poster 410, “Loss of knee motion after ACL reconstruction is associated with arthritic changes after surgery,” was authored by K. Donald Shelbourne, MD; Tinker Gray, MA, ELS; Heather Freeman, PT; and Scott E. Urch, MD. It was judged the best poster in the Sports Medicine category by the Sports Medicine Program Subcommittee; from the winning posters in each category, the members of the Program Committee selected this as the best overall poster. More than 565 posters were on display during the 2011 Annual Meeting in San Diego.
According to the poster authors, few studies have examined the association between ROM loss and arthritic changes on radiographs. One found that flexion contractures were associated with osteoarthritis (OA) at 7 and 13 years after surgery. Another study found that 15 years after surgery, 43 percent of those patients who had radiographic evidence of OA had loss of ROM versus only 14 percent of those with normal radiographs. Several studies have established that meniscectomy and articular cartilage damage are major risk factors for OA development.
The prospective study followed 780 patients who had ACL reconstruction a minimum of 5 years ago. ROM and radiographs were evaluated according to International Knee Documentation Committee objective criteria. Normal extension was considered to be within 2 degrees of the opposite knee, including hyperextension; normal knee flexion was considered to be within 5 degrees of the opposite knee. Radiographs were rated as abnormal if any sign of joint space narrowing, sclerosis, or osteophytes was present.
The following criteria were used for the study:
- Unilateral ACL injury
- No pre-existing evidence of OA before surgery
- No ACL graft tear after surgery
The obtained radiographs were bilateral knee views with a 45-degree posterior weight-bearing view, Merchant view, and lateral view.
Among patients with normal extension and flexion, 71 percent had normal radiographs. Among patients who had any deficit in ROM, only 55 percent had normal radiographs (p < 0.001). Among patients with intact menisci, 77 percent of those with normal motion had normal radiographs, while 67 percent of those who lacked normal motion had normal radiographs (p = 0.19).
Among patients who had a medial meniscectomy and retained normal motion, 56 percent had normal radiographs. Among those who had a medial meniscectomy without normal motion, only 38 percent had normal radiographs (p = 0.035). Similar statistical significance was found for patients with a lateral meniscectomy or both menisci removed.
Among the patients in this study, 92 percent had hyperextension in their knees, with the average being 5 degrees (range, 1 degree to 14 degrees). The authors note that subtle degrees of difference between knees can be evaluated by holding the thigh in place with one hand and using the other hand to hold the ball of the foot to lift the heel off the examination table. “This evaluation of passive knee extension should be compared to the other knee to feel subtle differences in extension,” the researchers observed.
Using ROM as a predictor
The authors concluded that “the data in this study confirm the importance of achieving and maintaining full and symmetric knee ROM, in order to lower the incidence of OA in the long term after surgery.”
Poster presenter Dr. Urch said the take-home message is that “something as simple as symmetric ROM correlates very well with having normal radiographs at 10-year follow-up. Regardless of the status of the meniscus at the time of surgery, better motion—particularly extension—was associated with better radiographs long term. Motion is a simple but very important concept that often gets overlooked.”
Disclosure information: Dr. Shelbourne—DJ Orthopaedics, Kneebourne Therapeutics, Inc.; Abbott; Pfizer; American Journal of Sports Medicine; Journal of Knee Surgery; AOSSM; Dr. Urch, Mr. Gray, Ms. Freeman—no conflicts.
- This prospective study of patients who underwent ACL reconstruction found an association between ROM after surgery and radiographic evidence of osteoarthritis after surgery.
- Achieving and maintaining full and symmetric knee ROM may help lower the incidence of OA in the long term after surgery.
- Regardless of the status of the meniscus at the time of surgery, better motion—particularly extension—was associated with better radiographs long term.
Terry Stanton is the senior science writer for AAOS Now. He can be reached at firstname.lastname@example.org
- Roe J, Pinczewski LA, Russell VJ, Salmon LJ, Kawamata T, Chew M: A 7-year follow-up of patellar tendon and hamstring tendon grafts for arthroscopic anterior cruciate ligament reconstruction: Differences and similarties. Am J Sports Med 2005;33:1337–1345.
- Salmon LJ, Russell VJ, Refshauge K, Kader D, Connolly C, Linklater J, Pinczewski LA: Long-term outcome of endoscopic anterior cruciate ligament reconstruction with patellar tendon autograft: Minimum 13-year review. Am J Sports Med 2006;34:721–732.
- Shelbourne KD, Gray T. Minimum 10-year results after anterior cruciate ligament reconstruction: How the loss of normal knee motion compounds other factors related to the development of osteoarthritis after surgery. Am J Sports Med 2009;37:471-480.