Correction to: Meniscal extrusion is positively correlated with the anatomical position changes of the meniscal anterior and posterior horns, following medial meniscal allograft transplantation.

The article Meniscal extrusion is positively correlated with the anatomical position changes of the meniscal anterior and posterior horns, following medial meniscal allograft transplantation.

Meniscal extrusion is positively correlated with the anatomical position changes of the meniscal anterior and posterior horns, following medial meniscal allograft transplantation.

PURPOSE: The purpose was to analyse the correlation between meniscal extrusion and position changes of the anterior horn and posterior horn after medial meniscal allograft transplantation. METHODS: Patients (n = 68) who underwent medial MAT were included. Anatomical positions of the anterior horn and posterior horn were measured, before and after surgery, using magnetic resonance images in the coronal and sagittal planes. The absolute and relative delta values of the anatomical positions were obtained, and the absolute and relative meniscal extrusion measurements were taken. RESULTS: In the coronal plane, the absolute position change of anterior horn showed moderate positive correlation with the absolute and relative meniscal extrusion. The relative position change of anterior horn showed moderate positive correlation with the absolute and relative meniscal extrusion. The absolute position change of posterior horn showed moderate positive correlation with the absolute and relative meniscal extrusion. The relative position change of posterior horn showed moderate positive correlation with the absolute and relative meniscal extrusion. In the sagittal plane, both absolute and relative position change of anterior horn showed no correlation with the absolute and relative meniscal extrusion, respectively. Both absolute and relative position changes of posterior horn showed nonsignificant weak correlation with the absolute and relative meniscal extrusion, respectively. CONCLUSION: Transplanting the meniscus close to its native position may reduce subluxation in medial meniscal allograft transplantation. As position changes in the coronal plane can affect the meniscal subluxation more than changes in the sagittal plane, the tibial bone tunnel should be carefully created in the correct anatomical position to avoid a large amount of coronal deviation. LEVEL OF EVIDENCE: Retrospective case series, IV.

Synergistic Neuroprotective Effect of Schisandra chinensis and Ribes fasciculatum on Neuronal Cell Death and Scopolamine-Induced Cognitive Impairment in Rats.

Mild cognitive impairment (MCI) is considered as a transitional stage between aging and Alzheimer's disease. In the present study, we examined the protective effect of Schisandra chinensis (SC) and Ribes fasciculatum (RF) on neuronal cell death in vitro and scopolamine-induced cognitive impairment in Sprague Dawley® rats in vivo. A mixture of SC and RF extracts (SC+RF) significantly protected against hydrogen peroxide-induced PC12 neuronal cell death. The neuroprotective effect of SC+RF on scopolamine-induced memory impairment in rats was evaluated using the passive avoidance test and the Morris water maze test. In the passive avoidance test, SC+RF-treated rats showed an increased latency to escape, compared to the scopolamine-treated rats. Moreover, SC+RF treatment significantly reduced escape latency in water maze test, compared to treatment with scopolamine alone. To verify the long-term memory, we performed probe test of water maze test. As a result, rat treated with SC+RF spent more time in the target quadrant. Consistent with enhancement of memory function, the brain derived neurotrophic factor (BDNF) and its downstream molecules (pERK, pATK, and pCREB) are increased in SC+RF treatment in hippocampal area compared with scopolamine treated group. These results suggest that a mixture of SC and RF extracts may be a good therapeutic candidate for preventing mild cognitive impairment.

Distinct extra-articular invasion patterns of diffuse pigmented villonodular synovitis/tenosynovial giant cell tumor in the knee joints.

PURPOSE: Pigmented villonodular synovitis (PVNS)/tenosynovial giant cell tumor (TGCT) is a benign, proliferative lesion of the synovium, the bursa, and the tendon sheath. Little is known about the anatomical distribution pattern of diffuse extra-articular PVNS/TGCT around the knee joint. In this retrospective study, anatomical distribution of PVNS/TGCT using magnetic resonance imaging (MRI) and arthroscopy was analyzed. METHODS: This study was designed as a retrospective, observational cross-sectional study based on MRI and arthroscopy. Twenty-four PVNS/TGCT patients (24 knees) who underwent arthroscopic or posterior open surgery between 2009 and 2016 were enrolled. Of these, eight intra-articular and 16 diffuse extra-articular PVNS/TGCT of the knee were classified. The anatomical locations of the PVNS/TGCT masses were determined with a newly devised mapping scheme. Analysis was performed on the prevalence of each compartment and agreement rates between each compartment. RESULTS: The point prevalence of intra-articular posterior compartment was higher in diffuse extra-articular PVNS/TGCT group compared with intra-articular PVNS/TGCT group. The point prevalence of diffuse PVNS/TGCT was most prevalent in the extra-articular posterolateral compartment (12 out of 16 diffuse extra-articular PVNS/TGCT patients, 75%) and second most common in the below to joint capsule compartment (11 out of 16, 68.8%). The agreement rate was the highest between intra-articular posterolateral and extra-articular posterolateral compartments (75%). CONCLUSION: Extra-articular invasion of diffuse PVNS/TGCT occurred in specific patterns in the knee joint. Extra-articular lesions were always accompanied by lesions in intra-articular compartments. In particular, lesions in the intra-articular posterior compartments were observed in all of the diffuse extra-articular PVNS/TGCT patients. The point prevalence of diffuse extra-articular PVNS/TGCT for each compartment was the highest [12 out of 16 (75%)] in extra-articular posterolateral compartment. In contrast, invasion to the extra-articular posteromedial side was less frequent [5 out of 16 (31.3%)] than to the extra-articular posterolateral side. Knowing where the lesions frequently occur may provide important information for deciding the timing, method, and extent of surgery. LEVEL OF EVIDENCE: Level IV.

Mobile-bearing unicompartmental knee arthroplasty in old-aged patients demonstrates superior short-term clinical outcomes to open-wedge high tibial osteotomy in middle-aged patients with advanced isolated medial osteoarthritis.

PURPOSE: The aim of the present study was to compare the clinical outcomes of mobile-bearing unicompartmental knee arthroplasty (MB-UKA) and open-wedge high tibial osteotomy (OWHTO) for advanced isolated medial osteoarthritis (OA). METHODS: Patients with advanced medial compartment OA (Ahlbäck grade ≥ II) who underwent either MB-UKA with Oxford Knee or OWHTO were included. The minimum follow-up was two years. Clinical outcomes were evaluated using the Hospital for Special Surgery (HSS) score, knee score (KS), and function score (FS) of the Knee Society Knee Scoring System. Pre-operative and post-operative values were compared within groups. Pre-operative and post-operative values and the degree of change were compared between the two groups. Radiologic progression of OA in either the lateral or patellofemoral compartment was evaluated. RESULTS: Forty knees (20 received MB-UKA, 20 received OWHTO) were enrolled. The mean age was higher in the MB-UKA group (67.9 ± 9.0 years) than in the OWHTO group (58.4 ± 5.5 years). The HSS score, KS, and FS were significantly increased post-operatively in both groups. The preoperative HSS score, KS, and FS were significantly lower in the MB-UKA than in the OWHTO group; however, only the post-operative HSS score was significantly higher in the MB-UKA group. The changes in HSS score and KS were also greater in the MB-UKA group. There was no significant difference in OA progression. CONCLUSIONS: Although there was an age difference between the two groups, MB-UKA demonstrated superior short-term clinical outcomes to OWHTO for advanced isolated medial OA. In particular, MB-UKA was more effective in terms of pain relief.

Does discoid lateral meniscus have inborn peripheral rim instability? Comparison between intact discoid lateral meniscus and normal lateral meniscus.

INTRODUCTION: Little is known about peripheral rim instability (PRI) of adult discoid lateral meniscus (DLM). We compared PRI of the intact DLM (iDLM) to those of intact normal lateral meniscus (LM) in adult patients and also investigated whether there was any association between PRI and DLM tears. MATERIALS AND METHODS: We investigated PRI in 17 DLMs and 60 normal LMs without tears during arthroscopic surgery for medial compartmental pathologies between June 2012 and October 2015. We also investigate PRI of torn DLM (tDLM) excluding peripheral tear to compare the PRI between intact and torn DLM. Stability parameters were measured using a probing hook and arthroscopic ruler at the anterior, middle, and posterior parts of the peripheral rim of the menisci: translating the anterior horn (AH) and mid-body (MB) and lifting the posterior horn (PH). RESULTS: AH and PH instabilities were greater in the iDLM group than in the iLM group (2.2 ± 1.4 vs. 0.9 ± 1.4 mm, p = 0.006 and 3.4 ± 1.7 vs. 1.7 ± 1.2 mm, p = 0.004, respectively). However, there was no significant difference in MB instability between two groups. In addition, no significant difference was observed in all the parameters between the iDLM and tDLM groups. CONCLUSION: Both iDLM and tDLM had greater PRI of the AH and PH than the iLM in adult patients. Thus, the DLM is prone to tear and careful inspection is needed not to overlook PRI of a DLM even if the peripheral attachment is intact. LEVEL OF EVIDENCE: Level 3, comparative study of anatomical instability of living subjects.

Arthroscopic partial meniscectomy in young patients with symptomatic discoid lateral meniscus: an average 10-year follow-up study.

INTRODUCTION: The aim of this study is to evaluate mid-to-long-term clinical and radiological outcomes after an arthroscopic partial meniscectomy for symptomatic discoid lateral meniscus (DLM) in young patients and to determine whether degeneration of the residual meniscus and articular cartilage progresses during the follow-up period using magnetic resonance imaging (MRI). MATERIALS AND METHODS: We retrospectively reviewed patients aged ≤ 40 years at surgery who underwent arthroscopic partial meniscectomy for symptomatic DLM and were followed up for ≥ 5 years. Lysholm knee scores and reoperation rates were assessed as clinical outcomes. Factors that affect clinical outcomes were evaluated. Tapper-Hoover classification and femorotibial angle were used for radiological assessment. The degree of degeneration of articular cartilages and residual meniscus was evaluated using preoperative and follow-up MRIs. RESULTS: A total of 73 knees (66 patients) were enrolled. The mean follow-up period was 10.0 years. The mean follow-up Lysholm knee score was 84.2 ± 14.5, and the reoperation rate was 32.9%. Follow-up Lysholm knee scores were related to duration of symptoms prior to surgery (ß = - 0.129, P = 0.003) and femorotibial angle at the last follow-up (ß = 1.362, P = 0.045). On simple radiographs, progression of arthritis of the lateral compartment was observed in 68.5% (49 knees). In MRI analyses, degeneration of the residual meniscus progressed in 52.9% (34 knees) (P < 0.001), and significant changes in modified Yulish scores were observed in both lateral femoral and tibial condyles (P < 0.001, both condyles). CONCLUSIONS: After an arthroscopic partial meniscectomy for symptomatic DLM, unfavorable clinical outcomes were shown in > 30% of the patients during a mean follow-up of 10.0 years. Clinical outcomes based on the patient-reported outcome measures were related to durations of symptoms prior to surgery and alignment at the last follow-up. In radiological and MRI assessments, progression of degeneration of articular cartilages in the lateral compartments of the knees and residual menisci was observed.

Long-term Survival Analysis of Meniscus Allograft Transplantation With Bone Fixation.

PURPOSE: To investigate the long-term clinical results and clinical survival rate of meniscus allograft transplantation (MAT) with bone fixation. METHODS: The inclusion criteria of this study were previous MAT with bone fixation technique in our institution and minimum follow-up duration of 8 years. Potential subjects were identified using the medical records and database that was prospectively collected from December 1996 to December 2005. The exclusion criteria were diffuse International Cartilage Repair Society grade IV articular cartilage degeneration that was not treated with a concomitant or staged cartilage repair procedure. Surgical indication for MAT was previous total or subtotal meniscectomy followed by persistent swelling and pain in involved compartment. Recommendations to return to contact sports or strenuous activities were not made. Clinical outcomes were evaluated using the modified Lysholm score, and comparison between preoperative and final Lysholm score was done using Student t-test. During the follow-up period, failure was defined as (1) subtotal resection of the allograft, (2) conversion to total knee arthroplasty, or (3) a modified Lysholm score less than 65 or that of the preoperative status. Survival analysis was performed using the Kaplan-Meier method. RESULTS: During the study period, 52 knees underwent MAT in our institution and 49 knees were eligible for this study. Three knees were excluded because they had diffuse grade IV cartilage degeneration in the respective compartment. Among the 49 knees enrolled, 34 underwent lateral and 15 underwent medial MAT. Two patients had bilateral lateral MAT. Of those 47 patients, 37 were male and 10 were female. Mean patient age at the time of the MAT was 30.4 ± 8.6 years. The median follow-up period was 11.5 years (8 to 17 years). The preoperative mean modified Lysholm score was 73.2 ± 10.6, which significantly increased to 89.4 ± 13.2 at the time of the final follow-up (P < .001). There were 2 failures noted at 6 months and 11.3 years, respectively, after MAT. All of the other allografts were surviving at the time of the latest follow-up. The 10-year survival rate was 98.0% (95% confidence interval [CI], 94.1%-100%), and the 15-year survival rate was 93.3% (95% CI, 83.7%-100%) according to the Kaplan-Meier analysis. CONCLUSIONS: MAT using the bone fixation techniques demonstrated a high clinical survival rate according to the long-term observation. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Magnetic Resonance Imaging Findings in Symptomatic Patients After Arthroscopic Partial Meniscectomy for Torn Discoid Lateral Meniscus.

PURPOSE: To evaluate the change in the thickness and width of the residual meniscus using magnetic resonance imaging (MRI) in patients who underwent arthroscopic partial meniscectomy for discoid lateral meniscus (DLM), to assess whether the degeneration of the articular cartilage in the lateral compartment of the knee progressed, and to evaluate clinical results. METHODS: Among the patients who underwent arthroscopic partial meniscectomy for DLM between January 1997 and December 2011, those who were aged 40 or below at surgery were followed up for at least 3 years, and received at least 2 follow-up MRIs that were retrospectively reviewed. MRIs were done in symptomatic knees. Using MRI, the relative thickness and width were measured in the anterior horn, midportion, and posterior horn. To determine whether the degeneration of the lateral compartment would progress, the articular cartilage was graded based on the Outerbridge classification in MRIs. The clinical results were evaluated using the Lysholm score. RESULTS: A total of 20 patients (21 knees) were included. The average follow-up period was 6.8 years. In residual meniscus, the relative thickness of the midportion decreased from 9.0% ± 2.4% to 7.3% ± 2.3% (P < .001), the relative thickness of the anterior horn decreased from 15.6% ± 4.3% to 14.3% ± 6.7% (P = .030), and the relative thickness of the posterior horn decreased from 20.0% ± 4.4% to 16.7% ± 6.7% (P = .019). A decrease in the relative width was observed in the midportion (12.4% ± 4.8% to 10.9% ± 4.9%, P = .003). No significant changes in size were observed in the medial meniscus. A progression of degeneration in the lateral compartment was observed. However, the clinical results did not present significant changes. CONCLUSIONS: In symptomatic patients after arthroscopic partial meniscectomy for DLM, the thickness and width of the residual meniscus decreases over time. The arthritic change of the lateral compartment of the knee progressed. However, the change in the size of the residual meniscus was of unknown clinical significance. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Complications after arthroscopic coracoclavicular reconstruction using a single adjustable-loop-length suspensory fixation device in acute acromioclavicular joint dislocation.

PURPOSE: The purpose of this study was to evaluate clinical and radiological outcomes after arthroscopically assisted coracoclavicular (CC) fixation using a single adjustable-loop-length suspensory fixation device for acute acromioclavicular dislocation and to report intraoperative and postoperative complications. METHODS: Eighteen consecutive patients with acute acromioclavicular dislocation underwent arthroscopically assisted CC fixation using a single TightRope (Arthrex, Naples, FL). Using the Rockwood classification, 3 patients had grade III dislocations, one patient had a grade IV dislocation, and 14 patients had grade V dislocations. RESULTS: The preoperative CC distance of the injured shoulder was 16.1 ± 2.7 mm (range, 11.2 to 21.0 mm), and it increased by 99% ± 36% (range, 17% to 153%) on average compared with the contralateral shoulder. The average CC distance was 10.5 ± 2.5 mm (range, 7.7 to 15.5 mm), and it increased by 30% ± 30% (range, -9.4% to 90%) at the final follow-up. Compared with immediate postoperative radiographs, the CC distance was maintained in 12 patients, increased between 50% and 100% in 4 patients, and increased more than 100% in 2 patients at final follow-up. However, there was no statistical difference in Constant scores between 6 patients with reduction loss (95.6 ± 4.5) and 12 patients with reduction maintenance (98.4 ± 2.5; P = .17). Perioperative complications occurred in 8 patients, including one case of acromioclavicular arthritis, one case of delayed distal clavicular fracture at the clavicular hole of the device, 3 cases of clavicular or coracoid button failures, and 3 cases of clavicular bony erosion. CONCLUSIONS: Satisfactory clinical outcomes were obtained after CC fixation using the single adjustable-loop-length suspensory fixation device for acute acromioclavicular joint dislocation. However, CC fixation failure of greater than 50% of the unaffected side in radiological examinations occurred in 33% of the patients within 3 months after the operation. Additionally, 8 patients (44%) had complications associated with the adjustable-loop-length suspensory fixation device and surgical technical problems. Despite acceptable shoulder function restoration, adequate care should be exercised in surgical treatment of acute acromioclavicular dislocation with a single adjustable-loop-length suspensory fixation device for optimal radiological outcomes. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Patellofemoral Chondromalacia Does Not Influence Radiographic and Clinical Outcomes following High Tibial Osteotomy.

Effect of patellofemoral (PF) chondromalacia on results of high tibial osteotomy (HTO) has not been identified. Therefore, the objective of the present study was to analyze the effect of PF chondromalacia on relatively short-term radiographic and clinical outcomes of HTO. Patients who underwent open wedge HTO (OWHTO) from February 2010 to January 2015 were enrolled. A total of 101 knees were divided into two groups: 56 knees without PF chondromalacia in group A, while 45 knees with PF chondromalacia extended to subchondral bone in group B. Radiologic outcomes were compared using mechanical tibiofemoral angle, ratio of weight-bearing line (WBL), and minimal joint space width of the lateral compartment. Clinical outcomes were compared using range of motion in affected knee, visual analog scale, modified Lysholm score, and Kujala score. The mean mechanical tibiofemoral angle was 4.6 degree in group A and 4.8 degree in group B. The mean ratio of WBL was 63.8% in group A and 63.6% in group B at final. The mean minimum joint space width of the lateral compartment was 5.8 mm in group A and 5.8 mm in group B on standing AP radiograph. It was 5.3 mm in group A and 5.4 mm in group B on Rosenburg view at final. The mean ROM was 137.2 degree in group A and 137.5 degree in group B. The mean visual analog scale was 2.1 in group A and 2.3 in group B at final. The mean modified Lysholm score was 90.6 in group A and 89.1 in group B at final. The mean Kujala score was 90.2 in group A and 89.1 in group B at final. PF chondromalacia does not influence short-term radiographic and clinical outcomes following OWHTO.

Efficacy and Safety of Sinetrol-XPur on Weight and Body Fat Reduction in Overweight or Obese Adults: A 12-Week, Randomized, Double-Blind, Parallel, Placebo-Controlled Trial.

This study investigated the effect of Sinetrol-XPur on weight and body fat reduction in overweight or obese Korean participants. Among 100 overweight or obese participants enrolled in a 12-week randomized, double-blinded, controlled study, 86 participants completed the trial. Participants took either two Sinetrol-XPur tablets (450 mg per tablet) or two placebo tablets once a day. Bodyweight, body fat percentage, body mass index (BMI), body fat mass, waist circumference, and various safety parameters were measured. After the 12-week intervention, a significant reduction was observed in the body fat mass (P = .030) by dual-energy X-ray absorptiometry (DEXA), body weight (P = .002), and BMI (P = .002) compared to the placebo. Body fat percentage (P = .007) by DEXA showed a significant reduction in the Sinetrol-XPur group, but no difference compared to the control group. Abdominal metabolic risks by computed tomography and blood biochemistry analysis were significantly decreased in the Sinetrol-XPur group, but there were no differences between the Sinetrol-XPur and placebo groups. Safety profiles were not different between the two groups. These results suggested that Sinetrol-XPur significantly reduced body weight, body fat mass, and BMI in obese Korean subjects, which confirms the antiobesity effect of Sinetrol-XPur in the Korean population.

Nonanatomic Horn Position Increases Risk of Early Graft Failures After Lateral Meniscal Allograft Transplantation.

BACKGROUND: The cause of early graft failure within 1 year of meniscal allograft transplantation (MAT) remains unclear. The association of early failure with a nonanatomic horn position of the allograft after lateral MAT with the keyhole technique has never been evaluated. HYPOTHESIS: A nonanatomic horn position of an allograft would be a significant risk factor for a premature graft tear as compared with an anatomically positioned allograft. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: From October 2007 to October 2016, 208 patients (214 knees) with primary isolated lateral MAT in a single center were enrolled. A >5-mm or 10% discrepancy between pre- and postoperative horn position was defined as "nonanatomic," and the early failure rate was compared. Among 214 cases of lateral MAT, 54 were nonanatomically positioned, and 160 were anatomically positioned. The early failures (within 1 year after MAT) were defined as (1) grade 3 signal intensities (tears) over one-third of the allograft on magnetic resonance image or (2) removal of more than one-third of the allograft because of tears. RESULTS: Among the early failure cases, 6 were in the nonanatomic group and 5 in the anatomic group. The failure rate was 11.1% (6 of 54) in the nonanatomic group and 3.1% (5 of 160) in the anatomic group, with a 5.1% (11 of 214) overall early failure rate. The nonanatomic horn position group had an increased risk of early graft failure as compared with the anatomically positioned group (odds ratio = 3.88; 95% CI, 1.13-13.26). Anteriorized and lateralized horn position was identified in the nonanatomic group as compared with the anatomic group. Differences in patient age, sex, body mass index, involved knee, cartilage status, alignment of lower extremity, and joint space width were not statistically significant between the groups. CONCLUSION: Horn position discrepancy was associated with an increased risk of early graft failures. Meticulous insertion of a bone bridge is needed to ensure anatomically correct horn positioning to avoid early graft failure in lateral MAT with the keyhole technique.

Meniscal Extrusion Does Not Progress During the Midterm Follow-up Period After Lateral Meniscal Transplantation.

BACKGROUND: Meniscal extrusion is related to degeneration of the native knee joint. However, the clinical effect of the phenomenon after meniscal allograft transplantation (MAT) has not been clearly identified. Purpose/Hypothesis: The purpose of this study was to evaluate the change in meniscal extrusion in both the coronal and sagittal planes after lateral MAT through the midterm follow-up period. We hypothesized that meniscal extrusion does not progress during the midterm follow-up period. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 46 patients with a mean follow-up of 51.1 ± 7.1 months were included in the study. The patients underwent lateral MAT using the keyhole technique. Postoperative magnetic resonance imaging (MRI) was performed at 6-week, 1-year, and midterm (3- to 5-year) follow-up. In the coronal plane, the absolute value of meniscal subluxation and the relative percentage of extrusion (RPE) were measured. In the sagittal plane, meniscal subluxation was measured as the absolute and relative anterior cartilage meniscal distance (ACMD) and posterior cartilage meniscal distance (PCMD). The joint-space width (JSW) on weightbearing radiographs with 2 different knee positions was measured preoperatively and at 1-year and midterm follow-up. The Lysholm score was assessed at the same time points. RESULTS: In the coronal plane, the mean absolute meniscal extrusion at 6-week, 1-year, and final follow-up was 2.90 ± 0.94, 2.85 ± 0.97, and 2.83 ± 0.89 mm, respectively, and the mean RPE was 27.0% ± 9.4%, 27.1% ± 10.1%, and 27.8% ± 9.7%, respectively. There were no statistically significant differences in absolute and relative coronal extrusion among the 3 time periods ( P > .05). The percentage of patients with meniscal extrusion (≥3 mm) was 37.0% at 6-week follow-up and 34.8% at 1-year and final follow-up. In the sagittal plane, the mean absolute ACMD was 2.59 ± 1.75, 2.58 ± 1.85, and 2.37 ± 1.60 mm, respectively, and the mean relative ACMD was 20.7% ± 13.1%, 20.6% ± 13.8%, and 19.0% ± 12.2%, respectively, at the 3 follow-up time points. The mean absolute PCMD was -1.23 ± 3.34, -1.28 ± 3.08, and -1.42 ± 2.77 mm, respectively, and the mean relative PCMD was -10.3% ± 25.9%, -11.0% ± 24.6%, and -12.2% ± 23.2%, respectively, at the same time points. Sagittal extrusion was not significantly different between the time points ( P > .05). The mean JSW at 2 days preoperatively, 1 year postoperatively, and midterm follow-up was 5.40 ± 1.07, 5.44 ± 1.04, and 5.43 ± 0.98 mm, respectively, on anterior-posterior radiographs with full extension, and it was 4.90 ± 0.94, 4.94 ± 0.98, and 4.89 ± 0.96 mm, respectively, on posterior-anterior radiographs with 45° of flexion. The mean JSW values were not significantly different between the 3 different time points ( P > .05). The mean preoperative Lysholm score was 58. 9 ± 8.3; the score increased to 90.4 ± 9.7 at 1 year postoperatively and 90.5 ± 10.1 at final follow-up, which is a significant improvement compared with the preoperative status ( P < .05). There was no statistically significant difference between the scores at the 2 postoperative time points ( P > .05). CONCLUSION: This study demonstrated that extrusion of the meniscal allograft did not significantly progress either in the coronal or sagittal plane after lateral MAT during the midterm follow-up period.

Does Lateral Meniscal Allograft Transplantation Using the Keyhole Technique Restore the Anatomic Location of the Native Lateral Meniscus?

BACKGROUND: It is important to restore the normal anatomy of the native meniscus in meniscal allograft transplantation (MAT) for successful surgical results. PURPOSE/HYPOTHESIS: The purpose of this study was to compare the anatomic positions of the anterior horn (AH) and posterior horn (PH) between the preoperative lateral meniscus and postoperative meniscal allograft after lateral MAT using the keyhole technique. We hypothesized that the keyhole technique could restore the preoperative anatomy of the native lateral meniscus. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between December 2012 and December 2014, a total of 70 patients underwent lateral MAT using the keyhole technique. The anatomic positions of both horns of the native lateral meniscus and the meniscal allograft were measured on magnetic resonance imaging (MRI). Preoperative MRI was performed 1 day before lateral MAT, while postoperative MRI was performed 2 days after lateral MAT. A percentage reference method was used to measure the location of both horns. RESULTS: For the AH, the mean delta value of the absolute position was 0.7 ± 1.8 mm (95% CI, 0.3-1.1 mm) in the coronal plane and 0.5 ± 1.6 mm (95% CI, 0.2-0.9 mm) in the sagittal plane, and the mean delta value of the relative position was 1.0% ± 2.3% (95% CI, 0.5%-1.6%) in the coronal plane and 1.1% ± 3.3% (95% CI, 0.2%-1.8%) in the sagittal plane. For the PH, the mean delta value of the absolute position was 2.4 ± 2.6 mm (95% CI, 1.8 to 3.1 mm) in the coronal plane and -0.1 ± 2.1 mm (95% CI, -0.6 to 0.4 mm) in the sagittal plane, and the mean delta value of the relative position was 3.3% ± 3.5% (95% CI, 2.5% to 4.2%) in the coronal plane and -0.3% ± 4.4% (95% CI, -1.3% to 0.8%) in the sagittal plane. Therefore, the AH moved by a mean of 0.7 mm laterally and 0.5 mm anteriorly (absolute values) and 1.0% laterally and 1.1% anteriorly (relative values) compared with the preoperative position. The PH moved by a mean of 2.4 mm laterally and 0.1 mm posteriorly (absolute values) and 3.3% laterally and 0.3% posteriorly (relative values) compared with the preoperative position. For the AH, the proportion of patients with an absolute delta value of ≥5 mm was 4.3% in the coronal plane and 2.9% in the sagittal plane. For the PH, the proportion of patients with an absolute delta value of ≥5 mm was 18.6% in the coronal plane and 4.3% in the sagittal plane. CONCLUSION: When comparing the position of the horns preoperatively and postoperatively, both horns showed mean relative postoperative positional changes of <5% of relative values and <5 mm of absolute values in both the coronal and sagittal planes. The keyhole technique in lateral MAT can reconstruct the lateral meniscus close to its native anatomic position by avoiding displacement of >5 mm in both the coronal and sagittal planes.

Prophylaxis for Venous Thromboembolism Following Total Knee Arthroplasty: A Survey of Korean Knee Surgeons.

PURPOSE: The purpose of this study is to provide information on the actual status and prevailing trend of prophylaxis for venous thromboembolism (VTE) following total knee arthroplasty (TKA) in South Korea. MATERIALS AND METHODS: The Korean Knee Society (KKS) developed a questionnaire with 6 clinical questions on VTE. The questionnaire was distributed to all members of KKS by both postal and online mail. Participants were asked to supply details on their specialty and to select methods of prophylaxis they employ. Of the total members of KKS, 27.9% participated in the survey. RESULTS: The percentage of surgeons who routinely performed prophylaxis for VTE was 60.4%; 19.4% performed prophylaxis depending on the patient's health condition; and the remaining 20.2% never implemented prophylaxis after surgery. The common prophylactic methods among the responders were compression stocking (72.9%), pneumatic leg compression (63.3%), perioral direct factor Xa inhibitor (46.9%), and low-molecular-weight heparin (39.5%). For the respondents who did not perform prophylaxis, the main reason (51.5%) was the low risk of postoperative VTE considering the low incidences in Asians. CONCLUSIONS: The present study involving members of the KKS will help to comprehend the actual status of VTE prevention in South Korea. The results of this study may be useful to design VTE guidelines appropriate for Koreans in the future.

Study on the effect of temperature and pressure on nickel-electroplating characteristics in supercritical CO2.

In this work, it was investigated the effect of solubility in supercritical CO2 on the nickel-electroplating characteristics. The plating characteristics could be controlled by electric resistance and dispersion in emulsion as well. CO2 concentration had better be controlled at lower concentration than 50 CO2 wt% to decrease electric resistance since supercritical CO2 is non-polar material. Non-ionic surfactant with EO/PO block copolymer was more efficient than any other surfactant and the dispersion at 0.2 surfactant wt% was better than at any surfactant concentration and over-added surfactant concentration over 0.2 wt% brought to the decrease of dispersion properties. Electric resistance was constant at 20Omega in ranging from pH 2.2 to pH 3.5 and increased slowly to 50Omega at pH 4 and rapidly to 400Omega at pH 5. Characteristics of nickel film has a close relation with solubility in supercritical CO2 and solubility is dependent on pressure and temperature. Solubility at 16 MPa was higher than that any other at pressure and at constant pressure of 16 MPa, solubility in supercritical CO2 increased with an increasing temperature from 31 to 45 degrees C and decreased over 45 degrees C.

Periprosthetic fractures following total knee arthroplasty.

Periprosthetic fractures after total knee arthroplasty may occur in any part of the femur, tibia and patella, and the most common pattern involves the supracondylar area of the distal femur. Supracondylar periprosthetic fractures frequently occur above a well-fixed prosthesis, and risk factors include anterior femoral cortical notching and use of the rotational constrained implant. Periprosthetic tibial fractures are frequently associated with loose components and malalignment or malposition of implants. Fractures of the patella are much less common and associated with rheumatoid arthritis, use of steroid, osteonecrosis and malalignment of implants. Most patients with periprosthetic fractures around the knee are the elderly with poor bone quality. There are many difficulties and increased risk of nonunion after treatment because reduction and internal fixation is interfered with by preexisting prosthesis and bone cement. Additionally, previous soft tissue injury is another disadvantageous condition for bone healing. Many authors reported good clinical outcomes after non-operative treatment of undisplaced or minimally displaced periprosthetic fractures; however, open reduction or revision arthroplasty was required in displaced fractures or fractures with unstable prosthesis. Periprosthetic fractures around the knee should be prevented by appropriate technique during total knee arthroplasty. Nevertheless, if a periprosthetic fracture occurs, an appropriate treatment method should be selected considering the stability of the prosthesis, displacement of fracture and bone quality.

Does Medial Meniscal Allograft Transplantation With the Bone-Plug Technique Restore the Anatomic Location of the Native Medial Meniscus?

BACKGROUND: Previous work has shown the importance of restoring the normal structure of the native meniscus with meniscal allograft transplantation. PURPOSE/HYPOTHESIS: The purpose of this study was to compare the anatomic positions of the anterior horn and posterior horn between the preoperative medial meniscus and the postoperative meniscal allograft after medial meniscal allograft transplantation with the bone-plug technique. The hypothesis was that the bone-plug technique could restore the preoperative structure of the native medial meniscus. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Between December 1999 and December 2013, a total of 59 patients (49 male, 10 female) underwent medial meniscal allograft transplantation by use of the bone-plug technique. The anatomic positions of both horns in the native medial meniscus and in the meniscal allograft were measured via MRI. The percentage reference method was used to measure the locations of both horns. RESULTS: On coronal MRI, the mean absolute distance of the posterior horn from the lateral border of the tibial plateau changed from 45.2 ± 3.3 to 48.1 ± 4.2 mm (P < .05), and the percentage distance of the posterior horn changed from 59.6% to 63.0% (P < .05). On sagittal MRI, the mean absolute distance of the posterior horn from the anterior reference point changed from 40.3 ± 3.0 to 42.0 ± 3.5 mm (P < .05), and the mean percentage distance of the posterior horn changed from 76.5% to 79.4% (P <.05). On coronal MRI, the mean absolute distance of the anterior horn from the lateral border of the tibial plateau changed from 41.3 ± 4.2 to 48.5 ± 5.6 mm (P < .05), and the mean percentage distance of the anterior horn changed from 54.5% to 63.8% (P < .05). On sagittal MRI, the mean absolute distance of the anterior horn from the anterior reference point changed from 5.5 ± 1.0 to 9.9 ± 2.9 mm (P < .05), and the mean percentage distance of the anterior horn changed from 10.6% to 19.0% (P < .05). CONCLUSION: Despite attempts to place the meniscal allograft in the same position as the native meniscus, the anatomic locations of both horns were shifted posteromedially compared with those of the native medial meniscus. There were significant differences, attributed to several limitations in the bone-plug technique, between the preoperative and postoperative values of both horns. However, the posterior horn showed a location change of <5 mm, on average, in both the coronal and sagittal planes, whereas the anterior horn showed a location change of ≥ 5 mm in the coronal plane but <5 mm in the sagittal plane.