High Rate of Early Revision After Custom-Made Unicondylar Knee Arthroplasty.

BACKGROUND: There has been a recent interest in custom-made partial knee arthroplasties to provide patient-specific instrumentation and better fit of the prosthesis. While unicondylar knee arthroplasties (UKAs) have demonstrated good outcomes and durable results in many studies, there is little evidence on outcomes of these custom-made implants. METHODS: We performed a retrospective review of all custom-made UKAs performed at our institution by one surgeon from 2008 to 2015. We analyzed preoperative demographics, clinical follow-up evaluations, and radiographs and performed an analysis of risk factors including age, gender, height, weight, body mass index, and tibial insert thickness. The incidence of revision surgery, radiographic failures indicating component loosening, and symptomatic clinically failed implants was calculated at an average of 54.0 months of follow-up. RESULTS: We analyzed 115 consecutive custom-made medial UKAs from a single surgeon at our institution and found 29 (25.2%) UKAs had failed at an average of 33.1 months after surgery. Reasons for failure included aseptic femoral loosening (10), aseptic tibial loosening (8), loosening of both components (4), infection (3), progression of osteoarthritis (2), pain (1), and dislodged polyethylene insert (1). We found a significant relationship between implant failure and body mass index; no other study variables were statistically significant. CONCLUSION: We found a relatively high rate of aseptic loosening and particularly femoral component loosening in the short- to intermediate-term follow-up period. While further study of larger numbers of custom-made UKA from multiple institutions may help verify these findings, we recommend careful consideration of the use of this implant.

Treatment of osteoarthritis of the middle-aged athlete.

Unicompartmental knee arthroplasty (UKA) has increasingly become an attractive alternative to total knee arthroplasty for early intervention. Clinical and biomechanical studies have shown that UKA offers advantages in early recovery, more natural function, and patient satisfaction. The literature has also shown that UKA exhibits a higher rate of revision than total knee arthroplasty, particularly in registry studies that include patients from outside of high-volume specialty centers. Patient-specific UKA offers the potential to close the gap between the known advantages of a partial knee solution and the documented risk of early revision. On the basis of the patient's own imaging data, patient-specific UKA allows for an anatomically matched implant design that provides personalized fit, full coverage of the tibial cortical rim, and preserves the femoral articulating geometry. These design advantages are paired with a patient-specific instrument system that provides reliable component placement and simplified balancing.

Independent drilling outperforms conventional transtibial drilling in anterior cruciate ligament reconstruction.

BACKGROUND: Optimal tunnel placement is critical in anterior cruciate ligament reconstructive surgery, yet the method used to drill the tunnels may compromise their placement. HYPOTHESIS: An independent drilling method versus a conventional transtibial drilling method will place tunnels in different locations and produce reconstructions with different kinematics. STUDY DESIGN: Controlled laboratory study. METHODS: Ten pairs of knees had anterior cruciate ligament reconstructions produced by either a conventional transtibial drilling method or an independent drilling method. The location of the tunnels was recorded, and the knees were tested for laxity in the normal state, with the anterior cruciate ligament removed, and with the anterior cruciate ligament reconstructed. A surgical navigation system guided the placement of the independently drilled tunnels and measured joint laxity in response to various combinations of anterior force and rotational torques. RESULTS: The conventional transtibial drilling method used in this study placed tibial tunnels posterior and femoral tunnels superior relative to their footprints and resulted in more vertical grafts. In contrast, the independently drilled tibial and femoral tunnels were more anterior and central in their respective footprints, resulting in more horizontal grafts. The horizontal grafts of the independent drilling method were superior to the vertical grafts of this study's transtibial drilling method in restoring normal anterior and rotational knee laxity. CONCLUSION: An independent drilling method can produce tunnels with superior function compared with tunnels produced by a conventional transtibial drilling method. CLINICAL RELEVANCE: Single-bundle anterior cruciate ligament reconstructions will be improved if grafts are centered in their anatomical insertions by an independent drilling method versus grafts placed by a conventional transtibial drilling method.