Placement of a polyurethane implant is not associated with a chondroprotective effect: comparative study with cases of isolated medial meniscectomy with at least five years of follow-up.

INTRODUCTION: Our main objective was to evaluate clinically and radiologically and compare patients who had undergone partial meniscectomy alone, with those who had received a partial meniscectomy in which a polyurethane implant was placed, with a minimum follow-up of 5 years. METHODS: We performed a prospective cohort study. Patients were randomly distributed into Group A if they only received meniscectomy or Group B if they received meniscectomy plus a meniscal implant (Actifit®). We performed preoperative, postoperative, and 5-year-follow-up functional and radiological evaluations (magnetic resonance imaging). RESULTS: Twelve patients (40%) were treated with meniscal implants (Group B); 18 (60%) were treated with a conventional meniscectomy (Group A). Tegner, Lysholm and KOOS scores were evaluated prior to surgery and at 5-year follow-up. Only the Lysholm score showed a significant difference between groups, with a score increase between the preoperative evaluation and the 5-year follow-up evaluation (p = 0.013). Preoperative and postoperative MRIs were both available in 19 cases (63.3%). Long-term follow-up MRIs were performed in 11 cases of group B. No significant differences were found in functional outcomes or MRI findings (WORMS cartilage score increase p = 0.360). Although total reabsorptions of the collagen meniscus implant were not statistically significant in younger patients, a tendency towards a higher reabsorption process was seen in older patients (p = 0.015). CONCLUSION: The placement of a polyurethane implant after a wide meniscectomy is not accompanied by a chondroprotective effect over time. There is no functional difference between implant placement and isolated meniscectomy. There is a discrepancy between good clinical results and radiologic appearance of these implants and their underlying cartilage. LEVEL OF EVIDENCE: II, therapeutic study.

Pie Crust Technique of the Deep Medial Collateral Ligament in Knee Arthroscopy: Ultrasound and Anatomic Study.

This article determines compartment opening of the medial articular space of the knee after pie crust (PC) technique of the medial collateral ligament (MCL) by ultrasound measurements and anatomic dissection. This is a cadaveric study of 12 specimens. Four anatomic references were marked on the skin. Distances between the femur and tibia in the internal compartment at 30 degrees of flexion were obtained with ultrasound measurements in four situations: with and without applying valgus force both prior and after the PC technique. Ultrasound measurements of the medial articular compartment were made twice and mean value was calculated. An anatomical dissection was performed and distances between the puncture marks and the infrapatellar branch of the saphenous nerve was measured. Lilliefors test of normality was applied and variables were expressed as mean and standard deviation (SD). Qualitative variables were expressed by absolute frequencies and percentages. Statistical significance was a two-tailed p-value of < 0.05. Prior to the PC technique, mean (SD) distance between the femur and tibia in the medial compartment were 14.2 (4.0) mm in basal conditions and 17.1 (3.7) mm when applying valgus force (p = 0.003). PC technique increased the mean (SD) distance by 1.9 (1.9) mm under basal conditions (p < 0.01) and 2.9 (1.6) mm when applying valgus force (p < 0.01). The infrapatellar branches of the saphenous nerve were not damaged and the mean (SD) distance between the punctures and the nerve was 9.0 (3.3) mm. The PC is a reproducible, safe, and measurable surgical technique that opens controllably the medial compartment. PC as described avoided damage to the nerve branches.