Early knee motion after open and arthroscopic anterior cruciate ligament reconstruction
Authors: Noyes Frank R. , Mangine Robert E. , Barber Sue 
Published: June 2007

The hypothesis proposed in this study was that the initiation of active and passive knee motion within 48 hours of major intraarticular knee ligament surgery would not have the deleterious effects of increasing knee effusion, hemarthrosis, periarticular soft tissue edema, and swelling.

We conducted a prospective study with randomized assignment of 18 patients into two groups: 9 patients in the "motion" group began 10 hours of daily continu ous passive motion (CPM) on the 2nd postoperative day, while the remaining 9 in the "delayed motion" group used a soft hinged knee brace with knee hinges locked at 10° of flexion and entered into the motion program on the 7th postoperative day. All knees were allowed full 0° to 90° of motion except for a total of seven knees with concomitant mensicus repairs and extraar ticular reconstructions where 20° to 90° of motion was allowed, limiting the last 20° of knee extension for the first 4 postoperative weeks to protect the repair. In all other respects, the rehabilitation program after surgery was the same for the two groups, including postoper ative compression dressings, exercises, and weight- bearing status.

Ten of the eighteen patients had acute ACL disrup tions and 8 had chronic ACL insufficiencies. There was an even distribution of acute and chronic knee cases and of open and arthroscopic ligament procedures in the early and delayed motion groups. Associated sur gery included four meniscus repairs, three medial col lateral ligament repairs, and one lateral collateral liga ment repair. Special suturing and fixation techniques were used at surgery to maintain the integrity of liga ment and meniscus structures, allowing the surgeon to feel safe in subjecting the joint to early postoperative motion. The objective parameters measured were KT- 1000 arthrometer measurements, Cybex isokinetic testing, girth measurements at four lower limb loca tions, range of motion goniometer measurements, post operative pain medications, and days of hospitalization. Starting intermittent passive motion on the 2nd post operative day did not increase joint effusion, hemar throsis, or soft tissue swelling. In both motion groups, postoperative joint effusions were absent after the 14th postoperative day. There was no statistically significant difference in knee extension or flexion limits, pain med ication used, or hospital stay in comparing the two knee motion programs.

An important finding of this study was the significant decreases in thigh circumference that occurred within the first few weeks of surgery, which progressed de spite a closely supervised inpatient and outpatient re habilitation program. The decreased thigh girth was related to the type of operative procedure. Arthroscopic reconstructions had only 25% to 38% of the loss of thigh girth found in open operative procedures. By the 7th postoperative day, the average circumference loss for the open reconstruction group (motion at 7th post operative day) was nearly 4 cm, compared with the arthroscopic group's average of 1 cm. By the 21 st postoperative day, all patients who underwent open procedures sustained an average of 6.5 cm thigh cir cumference decrease compared with a 2 to 3.5 cm loss in the arthroscopic group. We concluded that traditional rehabilitation protocols are often ineffective in prevent ing the significant quadriceps muscle atrophy that may occur within the first few days of surgery.

Of importance was the finding that initiating early knee motion did not stretch out ligamentous recon structions. We strongly recommend an early motion program to decrease the morbidity of major intraarti cular ligamentous procedures. The program is initiated within the hospital setting immediately after knee sur gery.