Summary

Fresh patella OCA is a viable salvage option for patients under 50 years old with large full thickness chondral lesions of the patella.

Abstract

Background

The purpose of this study is to report on the clinical, radiographic, and self-report outcome measures of a series of patients with large patellar osteochondral lesions treated with fresh patellar osteochondral allograft transplantation.

Methods

After approval from our institutional review board, we searched the practice of a fellowship trained, orthopaedic surgeon to identify patients who underwent OCA between June of 2010 and December 2013. All subjects >18yo who had an OCA for isolated patellar chondral lesions were included.
All patients had to present with patellofemoral symptoms with failure of >3months of conservative treatment and/or failure of improvement with previous surgery. MRI in all patients showed significant chondral lesion of the patella. Preoperative data collected included age, sex, BMI, side, location of lesion, and duration of symptoms.
A guidewire was placed in the center of the lesion and a reamer was used over the wire and subchondral bone was removed to a depth of 5-10mm. The graft was harvested from the fresh donor patella using a coring reamer. The prepared graft matched the appropriate depth to allow it to sit flush with the remainder of the native patellar cartilage and press fit using no hardware.
Data from radiographs included presence of patellar fracture, patellofemoral joint space narrowing, and signs of graft resorption.
A questionnaire examining preoperative and postoperative symptoms with daily activities, functional limitations, and satisfaction with surgery was asked to all participants. The primary outcome measure was the Modified d’Aubigne-Postel score. WOMAC, Lysholm, and SANE scores were also obtained.
Descriptive statistics to summarize the cohort were calculated using mean and standard deviation for continuous variables and frequency and proportion for categorical variables. Correlation analysis using Pearson product-moment correlation coefficient, point biserial, or Spearman rho were performed where appropriate to identify relationships between outcome measures and collected variables.

Results

14 subjects underwent isolated patellar OCA between June 2010 and December 2013 and completed final outcome measures at an average of 34.6 months postoperatively (range 25-57 months). The average age was 32 years (range 19-44). There were 9 males and 5 females.
Final assessment was obtained at 35 months (range 25-57). Twelve of the 14 were happy they had surgery although many still had some level of pain and functional limitation from their knee. average Modified d’Aubigne-Postel score was 15.5 (±2.8). Based on prior interpretation of this score, 4 patients were considered excellent, 5 good, 3 fair, and 2 poor. The average WOMAC was 12.7 (±15.9). Five of 14 subjects had a score of 0, indicating normal. The Lysholm score average was 72.6 (± 24.8). Five of 14 subjects had a score of greater than 90 with 100 indicating perfect function. The average SANE score was 68.6 (±31.4). Three of 14 rated their involved knee as 100%.

Discussion

Osteochondral allograft transplantation of the patella was shown to have good to excellent results in 64% of patients overall. 36% required additional surgery. Osteochondral allograft transplantation was a viable option for the young to middle-aged patient with significant patellar lesions.