2015 ISAKOS Biennial Congress ePoster #1431
Two Year Outcome of Unicompartmental Interpositonal Arthroplasty of the Lateral Compartment of the Knee, Utilizing a Metallic Implant
Arno Smit, MD, FRCSC, White Rock, BC CANADA
Peace Arch Hospital, White Rock, British Columbia, CANADA
FDA Status Not Applicable
Summary: Use of a newly designed metallic implant for interposiional arthroplasty as treatment for lateral compartment gonarthrosis was associated with a low complication rate and 68% confirmed retention of implants at two years, with satisfactory function in the majority of patients who could be confirmed to have a retained prosthesis by two years..
interpositional arthroplasty is a bone-preserving treatment option for unicompartmental gonarthrosis of which the risks and benefits have not been clearly defined. The initial experience with the Orthoglide-lateral (Advanced Bio Surfaces) lateral interpositional knee implant is presented as a one surgeon consecutive case series. No funding was provided or received for this study.
the prospectively collected records of all patients who received an interpositional arthroplasty for lateral compartment osteoarthritis of the knee were reviewed up to the two year mark for each patient. The study period was January 1, 2010, to July 15, 2014. Prior to surgery, patients had been thoroughly counselled about the uncertainties associated with the procedure. The implant was available through the Special Access Program of Health Canada. This study is the first report of clinical outcome of the use of this implant. The design of this implant is substantially different from the earlier introduced Orthoglide-medial implant for use in the medial compartment.
All procedures were performed under intra-venous sedation and local anesthesia, as a daycare procedure. Sufficient bone removal was needed to create a smooth tibial surface, using a burr or rasp. After arthroscopic preparation, a lateral arthrotomy of approximately 5-7 cm was made to allow implant insertion.
Outcome of the procedure was rated by the surgeon as 'good' (satisfactory, steady-state, likelihood of early revision low), 'fair' (implant merely tolerated, not a steady-state, likelihood of early revision high) or 'poor' (implant not tolerated, revision pending or performed).
Twenty-nine patients (22 women, 7 men) underwent arthroscopically assisted interpositional arthroplasty of the lateral compartment of the knee. All procedures were completed as intended. No conversion to general anaesthesia was needed. No patients required overnight stay or early re-admision. Two patients died due to unrelated causes within two years after surgery. Three patients had re-positioning of the implant, one for subluxation anteriorly, two for mesial subluxation, obliquely towards the intercondylar notch. Nineteen patients had surgery more than two years prior to the review or had faced revision or removal by two years. Four patients were lost to follow-up, one patient had the implant removed for early post-operative infection, one patient had a revision to a total knee replacement. Thirteen patient had the implant confirmed in situ at the two years mark. Of these, function was rated as ‘good’ in eleven patients, as ‘fair’ in two patients.
Interpositional arthroplasty for lateral compartment gonarthrosis is a treatment option with low initial morbidity. At two years, the implant could be confirmed to remain in situ in 13 out of 19 patients (68%). One revision to a total knee replacement was confirmed, one was removed for infection. The function of the 13 patients who retained the prosthesis in situ by two years after surgery was rated as ’good’ in 11 patients and as ‘fair’ in 2 patients. It is expected that future revision options are not significantly compromised by this procedure. Further study is needed regarding its efficacy.