This study comprised 24 consecutive patients operated between 2011 and 2016 with CC ligament reconstruction using an autogenous gracilis tendon graft. The hypothesis for this study was formulated in the end of 2011 after 5 patients had already undergone surgery, only postoperative outcome measures were available for these 5 patients and the study is therefore of combined prospective and retrospective design.
Patients between 18 and 75 years of age with chronic, symptomatic acromioclavicular joint dislocations that were planned for CC ligament reconstruction using autogenous gracilis tendon grafts were eligible for the study. Patients were excluded if they had unresolved knee injuries, ongoing joint diseases that affected the knee, previous knee surgery, other conditions that were likely to greatly effect outcome or were unable to understand or comply with postoperative rehabilitation protocols because of mental or systemic disease. The 5 patients operated before November 2011 were retrospectively included and preoperative outcome measures are therefore missing, the remaining 19 patients were prospectively included in the study.
The patients underwent CC ligament reconstruction using two different methods. The first 8 patients were operated using the GraftRope® device (Arthrex Inc., Naples, FL) and for the remaining patients the anatomic coracoclavicular reconstruction technique was used . The surgical technique was changed because of shoulder related complications with the GraftRope® device . To reconstruct the coracoclavicular ligaments an autogenous gracilis tendon graft was used in all cases, the surgical technique to harvest the graft was identical regardless of which reconstructive procedure was performed in the shoulder.
The tendon grafts were harvested immediately before the shoulder surgery and both the knee and shoulder were prepped and draped. Under general anesthesia and in a bloodless field a 4 cm incision was made over the pes anserinus, the saphenous nerve and infrapatellar branches were protected if located and the sartorius fascia incised. The common insertion of the semitendinosus and gracilis tendon was located and the gracilis tendon was identified as the most anterior of the two. Adhesions were bluntly dissected and the tendon was then harvested using a tendon stripper. The sartorius fascia and subcutaneous tissue was closed using absorbable sutures and the skin was closed using non-absorbable sutures. After a soft dressing was applied the tourniquet was deflated and the shoulder surgery was begun.
Full mobilization of the leg was allowed postoperatively but patients were given a crutch to allow for partial load bearing if pain required it. All patients were advised to perform physiotherapy but no supervised training was ordered as part of this study.
The primary outcome measure was the Knee injury and Osteoarthritis Outcome Score (KOOS). The questionnaire was completed 12 months postoperatively by all patients and scores were compared to preoperative ones for the prospectively included participants. For the patients included retrospectively preoperative scores were not available, therefore age- and gender matched normative values from a study of the general population were used for statistical analysis .
Isometric knee flexor strength was the secondary outcome measure. Testing was performed during a follow up visit for all included patients at the end of the study period. An IsoForceControl® EVO2 dynamometer (MDS Medical Devise Solutions AG, Oberburg, Switzerland) was placed on a vertical surface perpendicular to the direction of the force. The patient was in a prone position on an examination table with the strap from the dynamometer around the ankle. Instructions were given to hold on to the edges of the table and keep the pelvis low during attempts, no stabilization of the pelvis was used. After a trial attempt using submaximal force testing was performed on both the operated and non-operated leg with the knee in both 60° and 90°, three attempts per leg and angle were completed. In half of the patients the operated leg was tested first and in the other half the non-operated. The mean of the two highest values for each leg and angle was used for statistical analysis.
To find patients with clinically severe donor site related complications, such as infection, hematoma or muscle rupture, a medical journal review of the hospitals’ database was performed at the end of the study period.
For KOOS scores each subscale was analyzed separately and change from baseline at 12 months was analyzed using the Wilcoxon signed-rank test. For the participants that did not have preoperative scores, age- and gender matched normative values were used.
For the isometric knee flexor strength all analyses are performed as paired calculations. The relative force of the operated leg was calculated by dividing the values of this leg by those of the non-operated one. The actual difference between the legs was calculated by subtracting the force of the non-operated from that of the operated one. These calculations were performed for each patient separately and these values were then used for further calculations. The Wilcoxon signed-rank test was used to analyze if the actual difference and relative force differed from 0 and 1 respectively. Statistical significance was set at p < 0.05. All analyses were performed using SAS 9.4 (SAS Institute Inc., Cary, NC, USA).