Clinical and Functional Outcomes of Kinematic Aligned Total Knee Arthroplasty with a Medial Pivot Design: Two-Year Follow-Up.

BACKGROUND: Kinematic alignment (KA) restores native limb alignment following total knee arthroplasty (TKA). The association of this technique with a medial pivot implant design attempts to re-establish the physiological kinematics of the knee. This study aims to analyze the clinical and radiological outcomes of patients undergoing MP-TKA with kinematic alignment and to assess the effect of limb alignment on the clinical outcomes. METHODS: We retrospectively analyzed 55 patients who underwent kinematic aligned medial pivot TKA from September 2018 to January 2020. Patient-related outcomes (PROMs) were collected at baseline, 3, 12, and 24 months after surgery. Long-standing weight-bearing radiographs were performed three months after surgery. RESULTS: We demonstrated a significant improvement in clinical outcomes from 3 months after surgery up to 24 months of follow-up. This clinical improvement was independent of limb alignment. The radiological analysis showed that the patient's native limb alignment was restored and that their joint line orientation was parallel to the floor. CONCLUSION: The association of kinematic alignment and a medial pivot TKA implant allows for a fast recovery, with good clinical and functional outcomes up to a minimum of 2 years of follow-up, independent of the final limb alignment.

Analysis of Short-Term Clinical and Functional Outcomes in Patients Undergoing Total Knee Arthroplasty with Kinematic Alignment Technique.

BACKGROUND: Surgery remains the best option for more advanced stages of knee osteoarthritis (OA). Kinematic alignment (KA) is an innovative surgical technique that aims to co-align the rotational axes of the femoral, tibial, and patella components with the three kinematic axes of the knee. This study aims to evaluate and analyze short-term clinical, psychological, and functional outcomes in patients undergoing total knee replacement with the KA technique. METHODS: Twelve patients who underwent total knee replacement surgery with kinematic alignment from May 2022 until July 2022 were prospectively followed and interviewed. Before surgery, the day after surgery, and postoperative day 14, the following tests were evaluated: VAS, SF-12 PS, SF-12 MS, KSS, KSS-F, PHQ-9, and KOOS-PS. RESULTS: The mean BMI value of 30.4 (±3.4) Kg/m2, mean age of 71.8 (±7.2) years. All the scores on the various tests administered consistently showed statistically significant improvement, not only immediately after surgery but also comparing the first to the fourteenth postoperative day. CONCLUSION: Kinematic alignment technique as a surgical treatment for KO allows the patient a fast postoperative recovery and good clinical, psychological, and functional results in a short time. Further studies are needed with a larger sample size, and prospective randomized studies are essential to compare these results with mechanical alignment.

Evaluation of in Vivo Response of Three Biphasic Scaffolds for Osteochondral Tissue Regeneration in a Sheep Model.

Osteochondral defects are a common problem in both human medicine and veterinary practice although with important limits concerning the cartilaginous tissue regeneration. Interest in the subchondral bone has grown, as it is now considered a key element in the osteochondral defect healing. The aim of this work was to generate and to evaluate the architecture of three cell-free scaffolds made of collagen, magnesium/hydroxyapatite and collagen hydroxyapatite/wollastonite to be implanted in a sheep animal model. Scaffolds were designed in a bilayer configuration and a novel "Honey" configuration, where columns of hydroxyapatite were inserted within the collagen matrix. The use of different types of scaffolds allowed us to identify the best scaffold in terms of integration and tissue regeneration. The animals included were divided into four groups: three were treated using different types of scaffold while one was left untreated and represented the control group. Evaluations were made at 3 months through CT analysis. The novel "Honey" configuration of the scaffold with hydroxyapatite seems to allow for a better reparative process, although we are still far from obtaining a complete restoration of the defect at this time point of follow-up.

Osteochondral repair by a novel interconnecting collagen-hydroxyapatite substitute: a large-animal study.

A novel three-dimensional bicomponent substitute made of collagen type I and hydroxyapatite was tested for the repair of osteochondral lesions in a swine model. This scaffold was assembled by a newly developed method that guarantees the strict integration between the organic and the inorganic parts, mimicking the biological tissue between the chondral and the osseous phase. Thirty-six osteochondral lesions were created in the trochlea of six pigs; in each pig, two lesions were treated with scaffolds seeded with autologous chondrocytes (cell+group), two lesions were treated with unseeded scaffolds (cell- group), and the two remaining lesions were left untreated (untreated group). After 3 months, the animals were sacrificed and the newly formed tissue was analyzed to evaluate the degree of maturation. The International Cartilage Repair Society (ICRS) macroscopic assessment showed significantly higher scores in the cell- and untreated groups when compared with the cell+ group. Histological evaluation showed the presence of repaired tissue, with fibroblast-like and hyaline-like areas in all groups; however, with respect to the other groups, the cell- group showed significantly higher values in the ICRS II histological scores for "cell morphology" and for the "surface/superficial assessment." While the scaffold seeded with autologous chondrocytes promoted the formation of a reparative tissue with high cellularity but low glycosaminoglycans (GAG) production, on the contrary, the reparative tissue observed with the unseeded scaffold presented lower cellularity but higher and uniform GAG distribution. Finally, in the lesions treated with scaffolds, the immunohistochemical analysis showed the presence of collagen type II in the peripheral part of the defect, indicating tissue maturation due to the migration of local cells from the surroundings. This study showed that the novel osteochondral scaffold was easy to handle for surgical implantation and was stable within the site of lesion; at the end of the experimental time, all implants were well integrated with the surrounding tissue and no signs of synovitis were observed. The quality of the reparative tissue seemed to be superior for the lesions treated with the unseeded scaffolds, indicating the promising potential of this novel biomaterial for use in a one-stage procedure for osteochondral repair.

Fibrin-based model for cartilage regeneration: tissue maturation from in vitro to in vivo.

One of the crucial points for a successful tissue-engineering approach for cartilage repair is represented by the level of in vitro maturation of the engineered tissue before implantation. The purpose of this work was to evaluate the effect of the level of in vitro maturation of engineered cartilaginous samples on the tissue quality after in vivo implantation. Samples were obtained from isolated swine articular chondrocytes embedded in fibrin glue. The cell-fibrin composites were either cultured in vitro or directly implanted in vivo for 1, 5, and 9 weeks. Other experimental samples were precultured for either 1 or 5 weeks in vitro and then implanted in vivo for 4 additional weeks. All the samples were analyzed by histology, immunohistochemistry, biochemistry, and gene expression. The results strongly suggest that the in vivo culture in this model promoted a better tissue maturation than that obtained in the in vitro condition, and that 1 week in vitro preculture resulted in the primary structuring of the engineered composites and their subsequent maturation in vivo, without affecting the cell viability and activity, while a prolonged in vitro preculture caused a cell and matrix degeneration that could not be rescued in vivo.

An unusual cause of popliteal cyst.

We describe a surgical treatment for popliteal cyst in a 41-year-old woman affected by diffuse pigmented villonodular synovitis (PVNS) of the knee with extra-articular spreading. The treatment consists of an arthroscopic synoviectomy followed immediately by an open removal of the cyst. At 28-month follow-up, the patient is asymptomatic and no evidence of recurrence of PVNS has been seen. We believe that this double surgical approach may reduce the probability of recurrence of PVNS.

Two cases of tibial nerve compression caused by uncommon popliteal cysts.

We report 2 cases of a popliteal mass of very unusual origin that induced compression neuropathy. The signs and symptoms could have been mistaken for those of a common Baker's cyst. Several recent studies have shown that the cause of Baker's cyst formation should be sought within the joint because of a communication between the gastrocnemio-semimembranosus bursa and the joint cavity. These 2 cysts had no communication with the articular joint, thus suggesting that the surgeon perform an open exploration of the popliteal fossa in the search for other cystic formations with origins and features different from Baker's cysts.