The clinical outcome of the different HemiCAP and UniCAP knee implants: A systematic and comprehensive review

Abstract

The focal metallic cartilage resurfacing is a surgical method that offers an appropriate step between the biological techniques and arthroplasty in middle-aged patients with full-thickness cartilage defects. The advantages of this technique are that it addresses the defect, respects healthy tissues and provides stability and contoured surface similar to a full arthroplasty. A systematic review was conducted according to Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Two reviewers (MM and DC) independently conducted the search using the MEDLINE/PubMed database and the Cochrane Database of Systematic Reviews (CDSR). These databases were searched for the terms hemicap knee implant and unicap knee implant and knee focal metallic implant. From the initial 21 studies that were evaluated, 10 were eligible for analysis. Considering both the HemiCAP focal implant and the HemiCap® Wave patellofemoral prosthesis, we found a lack of mid- to long-term clinical outcomes in well-designed prospective clinical studies. No Level I or II studies were found, while the limited number of patients who were included undermines the overall clinical results of these studies. The progression of osteoarthritis, the persisting pain and the subsequent high revision or failure rates in the limited available studies with long-term follow-up, seem to be the major drawbacks of these partial resurfacing techniques. Utilization of partial resurfacing for femoral or patellofemoral compartments results in good short-term outcome for middle-aged patients as a step between biological technique and total knee arthroplasty. The surgeon should be cognizant and also notify the patient of the high failure rates that are reported in the literature in mid- to longterm follow-up and ultimately, the decision to perform partial resurfacing should be taken by both the patient and the orthopedic surgeon.

Focal inlay resurfacing for full-thickness chondral defects of the femoral medial condyle may delay the progression to varus deformity

“…Dhollander et al described a statistically significant increase in degenerated changes according to the Kellgren and Lawrence classification in the treated knees, based on nine out of 18 patients that were radiographically evaluated at 24 months [6]. It seems to be clear that progression to OA is not completely avoided with this technique [23], and further studies are therefore needed to better define the role of focal metallic implants in preventing the progression to OA. Becher et al described the 12-year follow-up of two cases that have been managed by means of a prosthetic resurfacing for full-thickness cartilage defect, and comparing the first post-operative to 12-year follow-up X-rays, the radiographic results demonstrated no signs of periprosthetic loosening, preservation of joint space and no change in the osteoarthritic stage [24].…”

What future in the treatment of osteochondral knee defects?

“…In particular, recently, a systematic review of the literature evaluated the outcomes of focal metallic inlay resurfacing for the treatment of isolated cartilage defects of the femoral condyles concluding that this system seems to be a viable option for carefully selected patients. The review reported a significant improvement in knee function and pain, also if many doubts remain as regards progression of osteoarthritis (6).…”

“…In this scenario has gained popularity the use of focal metallic implant, both for primary or revision surgery (6). The focal metallic cartilage resurfacing is a surgical method that offers an appropriate step between regenerative procedures and replacement surgery, especially in middleaged patients with full-thickness chondral lesions.…”

“…The focal metallic cartilage resurfacing is a surgical method that offers an appropriate step between regenerative procedures and replacement surgery, especially in middleaged patients with full-thickness chondral lesions. This technique allows to address the defect, to respect surrounding tissue and to provide a stability similar to replacement surgery (6).…”

Treatment of Unicompartmental Cartilage Defects of the Knee with Unicompartmental Knee Arthroplasty, Patellofemoral Partial Knee Arthroplasty or Focal Resurfacing

“…Furthermore, it is important to position implants accurately to avoid step offs or increased pressure on the opposite cartilage surface [ 18 , 86 ]. In addition, Malahias et al [ 87 ] reported that Arthrosurface inlay implants were associated with a postoperative effusion. They stated that these procedures should only be used if prior biological treatments failed.…”