Trend Shift in the Cause of Revision Total Knee Arthroplasty over 17 Years.

Background: The number of revision total knee arthroplasty (TKA) has been increasing. Although many studies have analyzed the causes of revision TKA in Western countries, a limited number of studies have analyzed changes in causes of or trends in revision TKA in Asia. This study analyzed and determined the frequency and causes of failures after TKA in our hospital. We also analyzed the differences and trends over the past 17 years. Methods: A total of 296 revision TKAs performed in a single institution from 2003 to 2019 were analyzed. During the 17-year study period, patients who had undergone primary TKA between 2003 and 2011 were classified into a past group, while those who had undergone primary TKA from 2012 to 2019 were classified into a recent group. A revision performed within 2 years after primary TKA was defined as early revision. Further, differences in causes of revision TKA according to the interval from primary TKA to revision TKA were determined. The causes of revision TKA were analyzed through a comprehensive analysis of patients' medical records. Results: Overall, infection was the most common cause of failure (151/296 cases, 51.0%). Compared to the past group, the recent group had a relatively higher proportion of patients undergoing revision TKA for mechanical loosening (past group, 19.1% vs. recent group, 31.9%) and instability (11.2% vs. 13.5%) and a relatively lower proportion of patients undergoing revision TKA for infection (56.2% vs. 48.8%), polyethylene (PE) wear (9.0% vs. 2.9%), osteolysis (2.2% vs. 1.9%), and malalignment (2.2% vs. 1.0%). On comparison according to the interval from primary TKA to revision TKA, the rate of infection relatively decreased, whereas the rate of mechanical loosening and instability relatively increased in the late revision TKA compared to the early revision TKA. Conclusions: Infection and aseptic loosening were the most common reasons of revision TKA in both past and recent groups. Compared to the past, revision TKA due to PE wear has decreased significantly and revision TKA due to mechanical loosening has relatively increased recently. Orthopedic surgeons need to be aware of recent trends in mechanisms of failure and should try to recognize and address the probable causes in TKA.

Effect of medial open wedge high tibial osteotomy on progression of patellofemoral osteoarthritis.

PURPOSE: This study aimed to investigate the effect of medial open wedge high tibial osteotomy (MOWHTO) on patellofemoral joint osteoarthritis (PF OA) progression and its outcome according to the degree of preexisting PF OA. MATERIALS AND METHODS: Patients who underwent biplane MOWHTO between January 2006 and December 2018 were retrospectively reviewed. The patients were divided into two groups according to the degree of PF OA: non-PF OA [Kellgren-Lawrence (K-L) grade 0-1] and PF OA (K-L grade 2-3). Propensity score matching was performed between the two groups, and comparative analysis was performed on clinical scores and radiographic parameters and grade. RESULTS: After propensity score matching, 83 patients were selected for each group. At postoperative follow-up, clinical scores were improved significantly compared with preoperative scores in both groups; however, there were no significant differences between the groups. There were also no significant differences between the two groups in radiographic parameters. The radiographic grade of PF OA indicated a slight progression in osteoarthritis in both groups; however, PF OA tended to progress further in the PF OA group. CONCLUSIONS: MOWHTO did not result in significant differences in outcomes at postoperative follow-up; however, preexisting PF OA contributed to PF OA progression after MOWHTO.

Clinical Outcomes of Anterolateral Ligament Reconstruction or Lateral Extra-articular Tenodesis Combined With Primary ACL Reconstruction: A Systematic Review With Meta-analysis.

BACKGROUND: Residual rotational instability after isolated anterior cruciate ligament reconstruction (ACLR) has been a challenge for many years. Anterolateral extra-articular procedures (AEAPs), including anterolateral ligament reconstruction (ALLR) or lateral extra-articular tenodesis (LET), are performed as a surgical option for additional rotational stability, but clear evidence for their usefulness is lacking. PURPOSE: To conduct a systematic review and meta-analysis of the literature regarding the efficacy of AEAP in primary ACLR. STUDY DESIGN: Systematic review; Level of evidence, 3. METHODS: A literature search, data extraction, and quality assessment were conducted by 2 independent reviewers. MEDLINE, EMBASE, and the Cochrane Library were searched in April 2020, following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. A total of 3444 studies were screened, and 20 studies (11 randomized controlled trials and 9 nonrandomized studies) were evaluated. Functional outcomes, stability, and complications were compared between patients who underwent primary ACLR with AEAP and those who underwent isolated primary ACLR. For subgroup analysis, outcomes were compared according to AEAP technique (ALLR vs LET) and time from injury to surgery (≤12 vs >12 months). The methodological quality of the included studies was assessed using the Cochrane risk-of-bias tool, Jadad scale, and Newcastle-Ottawa Scale. RESULTS: Compared with isolated ACLR, combined ACLR with AEAP led to improved pivot-shift grades and graft failure rates, regardless of the AEAP technique or of time from injury to surgery. A limited, marginal improvement in subjective function score was observed in patients who underwent AEAP combined with ACLR. In contrast to ALLR, patients who underwent LET combined with ACLR had an increased risk of knee stiffness and adverse events. CONCLUSION: Our review suggests that when there is a need to improve rotational stability and subjective function, AEAP combined with primary ACLR can be considered regardless of time from injury. ALLR appeared to be a better option for improving rotational stability compared with LET.

Spectrum of mitochondrial genome instability and implication of mitochondrial haplogroups in Korean patients with acute myeloid leukemia.

BACKGROUND: Mitochondrial DNA (mtDNA) mutations may regulate the progression and chemosensitivity of leukemia. Few studies regarding mitochondrial aberrations and haplogroups in acute myeloid leukemia (AML) and their clinical impacts have been reported. Therefore, we focused on the mtDNA length heteroplasmies minisatellite instability (MSI), copy number alterations, and distribution of mitochondrial haplogroups in Korean patients with AML. METHODS: This study investigated 74 adult patients with AML and 70 controls to evaluate mtDNA sequence alterations, MSI, mtDNA copy number, haplogroups, and their clinical implications. The hypervariable (HV) control regions (HV1 and HV2), tRNAleu1 gene, and cytochrome b gene of mtDNA were analyzed. Two mtDNA minisatellite markers, 16189 poly-C (16184CCCCCTCCCC16193, 5CT4C) and 303 poly-C (303CCCCCCCTCCCCC315, 7CT5C), were used to examine the mtDNA MSI. RESULTS: In AML, most mtDNA sequence variants were single nucleotide substitutions, but there were no significant differences compared to those in controls. The number of mtMSI patterns increased in AML. The mean mtDNA copy number of AML patients increased approximately 9-fold compared to that of controls (P<0.0001). Haplogroup D4 was found in AML with a higher frequency compared to that in controls (31.0% vs. 15.7%, P=0.046). None of the aforementioned factors showed significant impacts on the outcomes. CONCLUSION: AML cells disclosed more heterogeneous patterns with the mtMSI markers and had increased mtDNA copy numbers. These findings implicate mitochondrial genome instability in primary AML cells. Therefore, mtDNA haplogroup D4 might be associated with AML risk among Koreans.

Comparison of Outcome and Survival After Unicompartmental Knee Arthroplasty Between Navigation and Conventional Techniques With an Average 9-Year Follow-Up.

BACKGROUND: Unicompartmental knee arthroplasty(UKA) has become a treatment of choice for many patients with isolated unicomparmental arthritis due to its specific advantages over total knee arthroplasty, but few studies have compared conventional and navigational UKA with similar instrumentation on mid- to long-term results. We investigated whether the use of imageless navigation can improve implant positioning and clinical outcomes of UKA at a long-term follow-up compared to the conventional technique. METHODS: We prospectively studied clinical and radiological results in 68 patients with an average age of 64.0 years (range, 50 to 81 years) who received UKA between January 2003 and December 2005 using the conventional or navigational technique. Clinical evaluations were performed preoperatively and the last follow-up included knee range of motion, Hospital for Special Surgery (HSS) scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores and Visual Analogue Scale (VAS) pain score. For radiologic evaluation, the mechanical alignment of the lower limb was measured using mechanical femoro-tibial angle (mFTA) and Kennedy protocol. RESULTS: After an average 9-year follow-up (range, 7.4 to 10.8 years), the navigation group showed better coronal alignments of the components, fewer radiological outliers and better clinical scores, but similar estimated 10-year prosthesis survival rates. CONCLUSION: This study indicates that the use of navigation significantly contributes to the desired mechanical axis and improved component placement as compared to the conventional technique. LEVEL OF EVIDENCE: Prospective comparative study, Level III.

Bone Transport for Reconstruction in Benign Bone Tumors.

BACKGROUND: The aim of this study was to assess the results of using the Ilizarov apparatus to transport bones in the treatment of benign bone tumors. METHODS: Seven patients (six males and one female) with benign bone tumors were treated by bone transport with an Ilizarov apparatus at our institution. Their mean age at surgery was 14.4 years (range, 4.8 to 36.9 years). The histological diagnoses were osteofibrous dysplasia (4), giant-cell tumor (1), intraosseous cavernous hemangioma (1), and aneurysmal bone cyst (1). Three radiological indices were used for evaluating the results: an external fixation index, a distraction index, and a maturation index. The bone and functional results were evaluated according to the Association for the Study and Application of the Method of Ilizarov classification. RESULTS: Five patients had bone union at the reconstructed site, one patient had a local recurrence, and the other had a nonunion at the docking site. The mean length of distraction was 7.3 cm (range, 5.1 to 12.1 cm). The mean external fixation index was 26.0 day/cm (range, 19.8 to 32.5 day/cm), the distraction index was 9.6 day/cm (range, 6.8 to 12.0 day/cm), and the maturation index was 14.9 day/cm (range, 8.0 to 22.5 day/cm). Ultimately, the bone and the functional results were rated excellent in six cases and good in one case. CONCLUSIONS: Bone transport using the Ilizarov apparatus is a good treatment option in patients with bone defects after the resection of an active or aggressive benign bone tumor.