Objective: The purpose of this study was to investigate of the factors affected Short-term Outcomes in ACI (^®JACC).

Methods: The objects were 38 patients who were underwent JACC over 12 months with mean age 46.9 years. Isolate cartilage defect site was femoral medial condyle (MFC) 21 knees, femoral lateral condyle (LFC) 2 knees, tibia lateral condyle1 (TLC) knees, patella (P) 4 knees, femoral trochlar (Tr) 1 knee. Combined cartilage defect site were MFC+Tr 2 kees, LFC+Tr 1 kees, P+Tr 5 kees, MFC+P+Tr 1 knee. Mean cartilage defect area was 649.7±284.1 (400-1850) mm². KOOS (KOOS), Lysholm score (Lysholm) were evaluated as clinical score, and investigated both correlation with age, BMI and defect area and association with gender, implantation procedure and HTO.

Results: In all objects, 26, 52 weeks KOOS each items and Lysholm were higher significantly than previous that without 26 weeks sports item of KOOS. Complication after JACC was 4 Hypertrophys, 1 separation and 1 contracture which was underwent immobilization at 3 months after JACC. Post-operative KOOS under 30 years was significantly higher than that over 30 years without symptom items. There was no significant difference between with HTO and without HTO. But, Amount of KOOS changes from preoperative to postoperative with HTO was significant higher than that without HTO.

Conclusions: Large cartilage defect area, under 30 years and with HTO affected JACC good short-term outcomes.

Objective: The purpose of this study was to investigate postoperative outcomes in patients aged≥40 years old with medial meniscus (MM) tear complicated by early osteoarthritis (OA) that was treated with arthroscopic surgery alone.

Methods: The subjects were 13 patients (13 knees: 8 in males and 5 in females) with MM tear accompanied by Kellgren-Lawrence grade 0-Ⅱ early OA on plain radiography in the knee joint. All patients were treated with arthroscopic surgery alone at our hospital between January 2016 and December 2019. Evaluation items were clinical symptoms before and after surgery, MRI findings, preoperative plain radiographic findings, and intraoperative arthroscopic findings.

Results: The clinical outcome was favorable and meniscus tear-derived symptoms that were present before surgery improved in all patients after surgery. However, OA-derived symptoms remained in 2 knees.

Conclusion: We suggest that high tibial osteotomy may be an option for highly active patients with concomitant MM tear and symptoms of early OA.

Objective: Debridement, antibiotics, and implant retention (DAIR) is performed for periprosthetic joint infection (PJI) after total knee arthroplasty (TKA). The aim of this study was to identify prognostic factors associated with successful DAIR in patients with PJI.

Patients and methods: The study included 52 knees in 51 patients who were treated according to the same protocol for infected TKA. The outcome of treatment and the success rate of DAIR were assessed in these cases. Patient characteristics, timing of infection onset, time from onset of infection to start of treatment, and type of causative bacteria were compared between the implant retention group and the implant removal group, and factors associated with successful implant retention were investigated.

Results: The implant was ultimately retained in 17 of 52 (32.7%) knees, and the success rate for implant retention using DAIR was 45.9% (17/37 knees). The success rate for implant retention by the onset timing of infection was 50% in early postoperative infections, 61.5% in acute hematogenous infections, and 13.8% in late chronic infections, showing a low success rate for retention in cases of late chronic infection. The success rate for implant retention by time from onset of infection to start of treatment was 65.4% in those who started treatment ≤2 weeks and 0% in those who started ≥2 weeks (significantly different), suggesting the importance of early treatment. Calculation of a cutoff value using ROC curve demonstrated that performing DAIR between the onset of infection to day 13 results in a high probability of retaining the implant. Regarding the causative bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis led to poor outcomes with low success of retaining the implant.

Conclusion: To retain the implant in PJI after TKA, DAIR should be performed within 13 days of onset of infection, with consideration for the type of causative bacteria, in those with acute infections such as early postoperative infections and acute hematogenous infections.

 Rapid destructive coxopathy (RDC) is known as a disease condition in which severe destruction of the hip joint progresses rapidly. The pathophysiology and etiology are still unknown. It often needs to be differentiated from leg pain caused by lumbar spinal stenosis (LSS). Here, we report a case of bilateral RDC while treating LSS.

 An 80-year-old woman complained of bilateral thigh pain 5 years ago, when she was diagnosed with LSS, and her pain was relieved by medication and L3 nerve root block. Her symptoms were worsened 6 months ago, and she was referred to our hospital. She could not walk more than 10 meters due to severe bilateral thigh pain, and ranges of motion of the hip joints were slightly limited. Her radiographs and MRI showed destruction of the upper part of the bilateral femoral heads and acetabula. She underwent bilateral total hip arthroplasties. She tolerated tis procedure well, and postoperative course was uneventful. She could walk independently at the final follow-up.

 RDC is occasionally associated with spinal disorder such as LSS. Although RDC is a rare disease condition, it should be taken into consideration as differential diagnosis in the patients with lumbar disorders during follow-up.