Medially congruent total knee arthroplasty in valgus knee deformities yields satisfactory outcomes: a multicenter, international study.

PURPOSE: Postoperative instability represents one of the most common complications following primary total knee arthroplasty (TKA). To prevent this outcome, valgus deformities have been historically treated using more constrained implants. The purpose of this study was to evaluate the outcome of treating a moderate valgus deformity by combining a surgical technique used to release the postero-lateral soft tissue envelope with the use of a medially congruent (MC) TKA design without using classical, semi-constrained inserts. METHODS: Seventy-nine MC TKAs were performed by three surgeons at three institutions between 2016 and 2018 as part of a multicenter, international study. Inclusion criteria were: radiographic late-stage osteoarthritic knees with Ranawat's type 1 or 2 classification of valgus deformity and integrity of the medial capsular-ligament complex (less than 10 mm of medial opening during valgus stress test at 10° of knee flexion). Exclusion criteria were: BMI > 40; neuromuscular, metabolic, or immunologic disorders; or the inability to complete outcome measures or radiographic assessment. RESULTS: Seventy-seven patients (79 knees), 59 males and 18 females, were evaluated at 2-year minimum follow-up according to the Knee Society Score (KSS) and Forgotten Joint Score (FJS). Mean age at surgery was 70 years (range 48-91). The mean range of motion (ROM) improved from 110° (range 85°-130°) preoperatively to 121° (range 105°-135°) (p < 0.001) at the time of the last follow-up. Preoperative knee extension significantly improved from 3° (range - 15° to 20°) to 1° (range - 5° to 5°) of flexion at the last follow-up in all the patients. KSS and KSS Functional scores were 89 (range 65-100) and 82 points (range 55-100), respectively. The FJS obtained at the last follow-up was 72 (range 49-88). Two patients (2.5%) had major postoperative complications (one periprosthetic joint infection; one postoperative patellar fracture) requiring surgical interventions. CONCLUSIONS: In different surgeon's hands, the use of a modern medially congruent TKA design yielded good clinical outcomes at 2 years in a consecutive series of TKA in valgus arthritic knees. Postoperative instability was not recorded in this series and this finding was related to the high conformity design of the MC polyethylene insert, which significantly differs from classical posterior-stabilized (PS) designs. LEVEL OF EVIDENCE: IV.

Post-traumatic proximal radioulnar synostosis: results of surgical treatment and review of the literature.

BACKGROUND: Post-traumatic proximal radioulnar synostosis is a very rare and disabling condition whose surgical treatment has traditionally been viewed with pessimism. The results of the few case series in the literature are conflicting. Our aims were (1) to describe the clinical results of a case series treated surgically by a single elbow surgeon and (2) to review the literature. METHODS: Twelve patients were evaluated. Preoperative radiographs and computed tomography scans were performed. According to the Viola and Hastings classification, there was 1 case of type IC synostosis; 3, type IIA; 2, type IIIA; and 8, type IIIB. Two patients had a double synostosis. The synostosis was excised in 10 cases; in addition, radial head excision, radial head arthroplasty, and proximal radial diaphyseal resection were performed in 1, 3, and 2 cases, respectively. The Mayo Elbow Performance Score, modified American Shoulder and Elbow Surgeons score, and QuickDASH (short version of Disabilities of the Arm, Shoulder and Hand questionnaire) score were used for the preoperative and postoperative evaluation. The nonparametric Wilcoxon signed rank test was used for the statistical analysis. RESULTS: The mean follow-up period was 20.5 months. The final mean extension-flexion and pronation-supination arcs were 116° and 123°, respectively. Significant improvements were found in the Mayo Elbow Performance Score (P = .005), modified American Shoulder and Elbow Surgeons score (P = .012), and QuickDASH score (P = .002), with mean values of 24, 28, and 17, respectively. One synostosis recurrence and one late disassembly of the radial head arthroplasty were observed. CONCLUSIONS: Post-traumatic proximal radioulnar synostosis surgery is effective, but careful preoperative planning based on the pathoanatomic characteristics of each type of synostosis and associated lesions is mandatory. Synostosis excision is performed in most cases, whereas additional surgical procedures should be considered in selected cases.

Midterm results of radiocapitellar arthroplasty of the elbow: a multicentre prospective study on two different implants.

AIMS: The aim of this study was to analyze the results of two radiocapitellar prostheses in a large case series followed prospectively, with medium-term follow-up. PATIENTS AND METHODS: A total of 31 patients with a mean age of 54 years (27 to 73) were analyzed; nine had primary osteoarthritis (OA) and 17 had post-traumatic OA, three had capitellar osteonecrosis, and two had a fracture. Overall, 17 Lateral Resurfacing Elbow (LRE) and 14 Uni-Elbow Radio-Capitellum Implant (UNI-E) arthroplasties were performed. Pre- and postoperative assessment involved the Mayo Elbow Performance Score (MEPS), the Quick Disabilities of the Arm, Shoulder and Hand (Q-DASH) score, and the modified American Shoulder Elbow Surgeons (m-ASES) score. RESULTS: The mean follow-up was 6.8 years (3.8 to 11.5). The mean MEPS, m-ASES, and Q-DASH scores improved significantly by 50 (p < 0.001), 55 (p < 0.001), and 54 points (p < 0.001), respectively, with no differences being detected between the implants. Preoperative pronation and supination were worse in patients in whom the UNI-E was used. Two patients with the UNI-E implant had asymptomatic evidence of gross loosening. CONCLUSION: Radiocapitellar arthroplasty yielded a significant improvement in elbow function at a mean follow-up of 6.8 years, with a high implant survival rate when the LRE was used in patients with primary or post-traumatic OA, without radial head deformity, and when the UNI-E was used in patients in whom radial head excision was indicated. Cite this article: Bone Joint J 2019;101-B:1362-1369.

Cartilage thickness of distal humerus and its relationships with bone dimensions: magnetic resonance imaging bilateral study in healthy elbows.

BACKGROUND: Little is known about the cartilage thickness of the distal humerus and how it affects the shape of the articular surface. Our aims were to assess cartilage thickness and to determine the extent to which it affects the true profile of the distal humerus. METHODS: We assessed 78 healthy elbows (39 subjects, 19 women and 20 men) with a mean age of 28 years (range, 21-32 years). Cartilage thickness was measured by use of high-definition magnetic resonance imaging scans at 19 different points of the articular surface, 13 on the trochlea and 6 on the capitellum, on the axial and coronal views. Bone diameters at the medial and lateral trochlear ridges, trochlear groove, and capitellum, as well as the articular surface width, were measured. Subject height was used as an indirect measurement of humerus length. Pearson correlation coefficients and the Student t test were used. RESULTS: Cartilage thickness showed a significant variation (range, 0.4-1.8 mm) independent of sex and side. It appeared thinner at the medial and lateral edges, whereas it increased at the level of the trochleocapitellar and trochlear grooves, the lateral trochlear ridges, and the center of the capitellum. The mean bone diameters of the medial ridge, lateral ridge, trochlear groove, and capitellum measured 25.1 mm, 21 mm, 16.9 mm, and 19.6 mm, respectively. The mean width of the articular surface was 42.9 mm (range, 35.8-50.2 mm). No significant correlation was found between cartilage thickness and bone dimensions. CONCLUSION: Cartilage thickness is not uniform and modifies the morphologic shape and diameters of the humeral articular surface. These findings may be relevant to anatomic prosthesis design.