International Knee Society Knee Research Articles

Restoration of preoperative tibial alignment improves functional results after medial unicompartmental knee arthroplasty.

The alignment obtained after unicompartmental knee arthroplasty (UKA) influences the risk of failure. Kinematic alignment after UKA based on Cartier angle restauration is likely to improve clinical outcomes compared with mechanical alignment. The purpose of this study is to analyze the influence of implant alignment and native knee restoration after UKA using the conventional techniques on clinical outcomes. This retrospective study included 144 medial UKA patients from 2015 to 2020. Radiographic measurements were performed pre- and postoperatively. Outliers were defined as follows: Δ Cartier > 3° (difference between the preoperative and postoperative Cartier angle); Δ MPTA (Medial Proximal Tibial angle) and postoperative TCA (Tibial Coronal component Angle) > 3° (difference between the positioning of the tibial implant and the preoperative proximal tibial deformity). The Knee injury and Osteoarthritis Outcome Score (KOOS), the International Knee Society (IKS) Function and Knee score, the Forgotten Joint Score (FJS), and the Subjective Knee Value (SKV) were evaluated. A Student t test or a non-parametric Wilcoxon test was used for non-normal data to compare pre- and postoperative values for functional scores and angular measurements. The correlation of postoperative angles with functional outcomes was assessed by the Spearman's rank correlation coefficient. During the inclusion period, 214 patients underwent medial UKA, 71 patients were excluded, and 19 were lost to follow-up leaving 124 patients with 144 knees (20 bilateral UKA) included for analysis with a mean follow-up of 54.7months ± 22.1 (24-95). The Δ Cartier was significantly correlated with IKS function (R2 = 0.06, p < 0.001) and FJS (R2 = 0.05, p < 0.01) scores. The Δ preoperative MPTA-TCA was significantly correlated (p < 0.001) with KOOS (R2 = 0.38), IKS Knee (R2 = 0.17), IKS function (R2 = 0.34), SKV (R2 = 0.08), and FJS (R2 = 0.37) scores. In subgroup analysis, non-outliers (< 3°) for Δ preoperative MPTA-TCA had better KOOS score (Δ = 23.5, p < 0.001) and IKS Function (Δ = 17.7, p < 0.001) compared to outliers (> 3°) patients. Functional results after medial UKA can be influenced by implant alignment in the coronal plane with slight clinical improvement when positioning the tibial implant close to the preoperative tibial deformity, rather than by restoring the Cartier angle. This series suggests the interest of a more personalized alignment strategy, but these results will have to be confirmed by other controlled studies. IV, retrospective case series.

Intraarticular injection of microfragmented adipose tissue plus arthroscopy in isolated primary patellofemoral osteoarthritis is clinically effective and not affected by age, BMI, or stage of osteoarthritis

PurposeThis study aimed to report the clinical and functional results of a series of patients with isolated primary patellofemoral osteoarthritis (PFOA) treated with intraarticular injection of microfragmented autologous adipose tissue plus knee arthroscopy. The results were also analyzed in relation to the age and body mas index (BMI) of patients, and to the stage of PFOA.MethodsTwenty-three patients with early-to-moderate (stage 1–3 according to the Iwano classification system) PFOA who received this treatment were retrospectively analyzed, with a mean follow-up of 22.1 ± 4.2 months. Patients were assessed using the International Knee Society (IKS) knee and function and visual analog scale (VAS) scores, and relative to their capacity for climbing stairs. Differences in improvements of IKS and VAS scores in relation to age (< 60 versus ≥ 60 years), BMI (< 30 versus ≥ 30 kg/m2), and stage of PFOA (stages 1–2 versus stage 3) were finally analyzed.ResultsThe mean IKS knee score significantly improved from 35.6 ± 14.9 points preoperatively to 61.9 ± 17.8 points at the latest follow-up, while the mean IKS function score significantly improved from 52.0 ± 14.7 points preoperatively to 82.3 ± 19.1 points at the latest follow-up. The mean VAS score significantly decreased from 8.7 ± 2.2 preoperatively to 5.2 ± 2.5 at the latest follow-up. A significant improvement in the capacity to climb stairs was found. No significant differences in improvements of IKS knee and function and VAS scores were found in relation to age, BMI, or stage of PFOA.ConclusionIntraarticular injection of microfragmented autologous adipose tissue following arthroscopic debridement significantly improved overall clinical and functional scores in patients with early or moderate isolated primary PFOA at a mean follow-up of almost 2 years. Improvements were not significantly affected by age, BMI, or stage of PFOA.Level of evidenceLevel IV, retrospective case series.

Long-term follow-up of a non-randomised prospective cohort of one hundred and ninety two total knee arthroplasties using the NexGen implant.

The purpose of this study was to retrospectively analyse the clinical, functional and radiological outcomes, and the long-term survivorship of the NexGen Legacy Posterior Stabilised (LPS) knee prosthesis (Zimmer Biomet, Warsaw, IN, USA). Between 1996 and 2001, 197 primary NexGen LPS total knee arthroplasties (TKAs) were implanted by a single surgeon; 132 prostheses in 124 patients with a minimum follow-up of 15years were included in the study. Surgical procedure and post-operative care were the same for all patients. All patients were assessed through the International Knee Society (IKS) scores and range of motion (ROM). A complete radiological study was performed for all patients. Failure was defined as revision of at least one prosthetic component for any cause. IKS knee and function scores, as well as ROM and leg alignment, significantly improved at the latest follow-up (p ≤ 0.05). No significant differences were found between fixed- and mobile-bearing groups. Seven implant failures were reported; the implant survival rate (overall) was 94.7% at the latest follow-up. This study showed optimal survivorship of the NexGen LPS, associated with a significant improvement in overall outcomes at a minimum follow-up of 15years.

Arthroscopic Treatment of Isolated Hoffa Fractures.

The goal of this study was to evaluate the results of a novel method, arthroscopic fixation of isolated Hoffa fractures.This is a prospective, case series and set at Level 1 trauma center. A total of eight patients with isolated Hoffa fractures who were operated by arthroscopic screw fixation method in the anterior posterior direction with 6.5 mm cannulated screws were followed up prospectively. Same surgical method used for all patients. All patients underwent the same rehabilitation program and active range of motion (ROM) exercises were started immediately. The International Knee Society (IKS) knee and functional scores, postoperative knee ROMs, and time of bone union were used as outcome measurements. Postoperative knee ROMs was compared with the contralateral healthy knee. The mean follow-up time was 29 months (26 - 41 months). At the final review, no significant difference (p = 0.159) was found between the ROM of healthy side and operated side of patients (153.1 ± 4.6 and 150 ± 3.8). The mean IKS knee and functional scores at 12 months were 87.2 ± 5.8 and 96.8 ± 3.7, respectively. Union was achieved in all patients at a mean duration of 3.8 months. Fracture side had no influence on the IKS knee scores, functional scores, and ROM (p = 0.846, p = 0.913, and p = 0.374, respectively). Concomitant intra-articular lesions identified in two patients (%25) during arthroscopy were one anterior cruciate ligament rupture and one medial meniscus tear. Patients undergoing arthroscopic Hoffa fracture fixation have excellent outcomes at average 29 months postoperatively with no apparent complications and no significant loss of ROM. Also 25% of patients had intra-articular injuries that were identified with arthroscopic technique that may have been missed with the open technique. The level of evidence was Level 4 (case series).

The Computer-Aided-Surgery Improved the Accuracy of Femoral Component Rotation in Total Knee Arthroplasty for the Advanced Osteoarthritis with Valgus Deformity

Purpose: Arthritic knees with genu valgus deformity present with soft tissue and osseous anomalies that make Total Knee Arthroplasty (TKA) difficult. We retrospectively investigate whether advanced valgus deformity would benefit from Computer-Aided Surgery-TKA (CAS-TKA). Materials and methods: From January 2003 to September 2011, twenty-six patients having osteoarthritis with valgus deformity in the mechanical axis more than 10 degrees who underwent CAS-TKA were entered into this retrospective study. The usefulness of CAS-TKA was analyzed by the accuracy of placement of the components and postoperative alignment determined using radiographic parameters and Computed Tomography (CT). The Hospital for Special Surgery (HSS) and International Knee Society (IKS) functional scores were obtained for all patients preoperatively and postoperatively. Results: The mean postoperative mechanical axis was 181° (range, 176°-181°). The CT revealed proper femoral and tibial rotational alignment. The joint line was not substantially elevated. No patient required conversion to a constrained TKA to achieve stability. At a mean follow-up of 43 months, the Hospital for Special Surgery (HSS) knee score improved from a mean preoperative score of 54 to 92 postoperatively. The International Knee Society (IKS) clinical score improved from 38 to 97. The IKS for pain improved from 15 to 48, and the IKS knee function score improved from 32 to 96. The active range of motion from 95° to 115°. Conclusions: Computer-aided surgery-TKA is a useful alternative technique for advanced valgus knee arthritis where accurate restoration of the joint line, proper alignment of the limb and prosthetic components in coronal, sagittal and axial plane may be challenging because of bony deformities and soft tissue contractures.