The Effect of Intramedullary vs Extramedullary Tibial Guides on the Alignment of Lower Extremity and Functional Outcomes Following Total Knee Arthroplasty: A Randomized Clinical Trial.

Objectives: Total knee arthroplasty (TKA) has been known as a definitive treatment for advanced knee osteoarthritis. Both intramedullary (IM) and extramedullary (EM) tibial guides have been used to restore the desired extremity alignment. However, controversy exists regarding the superiority of either technique We aimed to compare the functional outcomes and accuracy of IM and EM tibial guides in providing neutral alignment after TKA. Methods: In a randomized, double-blinded clinical trial, we studied 98 patients undergoing primary TKA in two groups of IM and EM. We measured the medial proximal tibial angle (MPTA), varus angle (VA), and joint-line convergence angle with normal ranges of 90°±3°, 0-2°, and 0±3°, respectively, on a three-joint alignment view after three months. We also assessed the functional outcomes at the last follow-up. Finally, we compared these outcomes between the two groups. Results: Eighty-four patients (IM=42, EM=42) were included in the final analysis (16 males, 68 females, mean age: 63.9±8.6 years, mean follow-up: 13±2.9 months). The mean postoperative (post-op) alignment angles showed no significant difference, although MPTA outliers were significantly more frequent in the EM group (26.2% vs. 9.5% in IM, P=0.04). None of the functional outcomes showed a significant difference between the two groups. However, the mean increase in knee range of motion (ROM) was significantly higher in the knees with VAs within ±3° of neutral than those outside this range (30.8 vs. 27.4, respectively, P=0.039). Conclusion: We conclude that both techniques were not different regarding the mean alignment angles and functional outcomes. However, fewer MPTA outliers can be seen with the IM technique. A post-op mechanical axis within ±3° of neutral can result in a more ROM increase after one year.

Erratum to 'Late-Onset De Novo Genu Recurvatum After Primary Total Knee Arthroplasty: A Potential Indication for Isolated Polyethylene Exchange' [Arthroplasty Today 6 (2020) 492-495].

[This corrects the article DOI: 10.1016/j.artd.2020.05.014.].

Femur originated genu varum in a patient with symptomatic ACL deficiency: a case report and review of literature.

BACKGROUND: Anterior cruciate ligament (ACL) injury may be associated with genu varum. There are a few indications in which the varus deformity can be corrected at the time of ACL reconstruction. However, as the genu varum originates mostly from the tibia and the simultaneous presence of ACL deficiency and femur originated genu varum is uncommon, only a few papers have described their management for ACL deficient patients with femur originated genu varum. CASE PRESENTATION: A young patient visited our clinic with a complaint of right knee pain and giving way. Further work up revealed a full mid substance ACL tear, mild medial knee osteoarthritis and femur originated genu varum of his right knee. He was managed with simultaneous ACL reconstruction and distal femoral valgus osteotomy. CONCLUSIONS: Any corrective osteotomy for genu varum should be performed at center of rotation angle. Isolated ACL reconstruction in patients with simultaneous ACL deficiency and genu varum may hasten the knee degeneration. LEVEL OF EVIDENCE: IV.

Total Knee Arthroplasty and Atypical Cartilaginous Tumor/Enchondroma of the Distal Femur.

Enchondroma is a common benign chondrogenic tumor, which typically occurs in the short bones of hands and feet. However, when affecting the long bones, it is difficult to rule out the low-grade chondrosarcoma, called atypical cartilaginous tumor (ACT), because of the highly similar clinical and radiologic features. This study reports 2 patients with advanced knee osteoarthritis, scheduled for total knee arthroplasty, who had a distal femoral lesion on imaging suggestive of ACT/enchondroma. We believe that the treatment of these patients could be a challenge for arthroplasty surgeons. This is because it might be difficult to decide whether a periarticular chondral tumor of an osteoarthritic knee is malignant and changes the plan. In this report, we described our approach to address both knee osteoarthritis and ACT/enchondroma of the distal femur. To the best of our knowledge, this issue has not yet been discussed in the literature.

Late-Onset De Novo Genu Recurvatum after Primary Total Knee Arthroplasty: A Potential Indication for Isolated Polyethylene Exchange.

Knee instability is the second most common cause of revision after total knee arthroplasty (TKA). Genu recurvatum (GR) is the rarest form of instability usually occurring in patients with underlying conditions such as neuromuscular disorders and fixed valgus deformities. The literature regarding de novo post-TKA GR and its treatment is scarce. In this case series and review of literature, we aimed to review the treatment strategies of post-TKA GR and to present our experience in the treatment of late-onset de novo GR after TKA by isolated polyethylene exchange. To our knowledge, isolated polyethylene exchange has not been so far described for GR correction after TKA. We found a unique wear pattern at the base of the liner post in all 3 patients. They showed a satisfactory outcome with no recurrence on a mean follow-up of 26.67 months.