Epidemiology of Bearing Dislocations After Mobile-Bearing Unicompartmental Knee Arthroplasty: Multicenter Analysis of 67 Bearing Dislocations.

BACKGROUND: This study investigated the epidemiology and causes of bearing dislocations following mobile-bearing unicompartmental knee arthroplasty (MUKA) and determined whether the incidence of primary bearing dislocations decreases as surgeon experience increases. METHODS: We retrospectively reviewed the bearing dislocations following MUKAs performed by 14 surgeons with variable experience levels. Causes of bearing dislocations were determined based on the surgical records, radiographs, and operator's suggestion. Using a chi-squared test, the incidence of bearing dislocation was compared between the first 50, the second 50, and the next 100 unicompartmental knee arthroplasties (UKAs) of each surgeon's cohort. RESULTS: There were 67 (3.6%) bearing dislocations from 1853 MUKAs. The mean time to bearing dislocations after index MUKAs was 33 months (range, 1-144 months); 55% of the bearing dislocations occurred within 2 years after the index MUKAs. Primary bearing dislocations (n = 58) were the most common, followed by secondary (n = 6) and traumatic dislocations (n = 3). There was no significant difference in the incidence of bearing dislocation between the first 50 and second 50 UKAs for each surgeon. Two surgeons showed a significant decrease in bearing dislocations in their second 100 UKAs, while the other surgeons did not show a difference between their first 100 and second 100 UKAs. CONCLUSION: Most bearing dislocations after MUKAs were related to technical errors such as component malposition or gap imbalance. This study did not confirm that the incidence of bearing dislocations decreases as the number of cases increases. LEVEL OF EVIDENCE: IV, Case series.

Hamstring autograft maturation is superior to tibialis allograft following anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: Using second-look arthroscopy, graft maturation was investigated and compared between hamstring (HA) autografts and tibialis anterior (TA) allografts after anatomic single-bundle anterior cruciate ligament reconstruction (ACLR). METHODS: Fifty-six patients who underwent second-look arthroscopy after anatomic single-bundle ACLR with either HA autografts (26, HA group) or TA allografts (30, TA group) from 2007 to 2016 were retrospectively reviewed. Graft maturation on second-look arthroscopy was evaluated in terms of four parameters: graft integrity (tear), synovial coverage, graft tension, and graft vascularization. Each parameter received a maximum of two points, depending on the status of the reconstructed graft. The total graft maturation score was calculated as the sum of the parameter scores. The total graft maturation and individual parameter scores were compared between the two groups. RESULTS: The mean time from ACLR to second-look arthroscopy was 22.5 ± 7.8 months. The maturation scores in the HA group were significantly better in terms of graft integrity (p = 0.041), graft tension (p = 0.010), and graft vascularization (p = 0.024), whereas the graft synovial coverage score was not significantly different. The total graft maturation score of the HA group was significantly higher than that of the TA group (6.3 ± 0.4 vs. 4.9 ± 0.3, p = 0.013). CONCLUSIONS: This study shows the superior graft maturation of HA autografts compared with that of TA allografts at a mean follow-up of 22.5 ± 7.8 months after anatomic single-bundle ACLR. When anatomic ACLR using soft tissue graft is planned, HA autograft is recommended rather than soft tissue allograft, especially in young and active patients. LEVEL OF EVIDENCE: Retrospective cohort review, Level III.

What Factors Are Associated With Femoral Component Internal Rotation in TKA Using the Gap Balancing Technique?

BACKGROUND: When using the gap-balancing technique for TKA, excessive medial release and varus proximal tibial resection can be associated with internal rotation of the femoral component. Previous studies have evaluated the causes of femoral component rotational alignment with a separate factor analysis using unadjusted statistical methods, which might result in treatment effects being attributed to confounding variables. QUESTIONS/PURPOSES: (1) What pre- and intraoperative factors are associated with internal rotation of the femoral component in TKA using the gap balancing technique? (2) To what degree does femoral component rotation as defined by the navigation system differ from rotation as measured by postoperative CT? METHODS: Three hundred seventy-seven knees that underwent computer-assisted primary TKA attributable to degenerative osteoarthritis with varus or mild valgus alignment in which medial soft tissue release was performed, and those with preoperative radiographs including preoperative CT between October 2007 and June 2014 were included in the study. To achieve a balanced mediolateral gap, the structures released during each medial release step were as follows: Step 1, deep medial collateral ligament (MCL); Step 2, superficial MCL (proximal, above the pes anserine tendon) and semimembranosus tendon; and Step 3, the superficial MCL (distal, below the pes anserine tendon). Knees with internal rotation of the femoral component, which was directed by navigation, to achieve a rectangular mediolateral flexion gap were considered cases, and knees without internally rotated femoral components were considered controls. Univariable analysis of the variables (age, sex, BMI, operated side, preoperative hip-knee-ankle angle, preoperative medial proximal tibial angle, preoperative rotation degree of the clinical transepicondylar axis [TEA] relative to the posterior condylar axis [PCA], coronal angle of resected tibia, resection of the posterior cruciate ligament, type of prosthesis, and extent of medial release) of cases and controls was performed, followed by a multivariable logistic regression analysis on those factors where p equals 0.15 or less. For an evaluation of navigation error, 88 knees that underwent postoperative CT were analyzed. Postoperative CT scans were obtained for patients with unexplained pain or stiffness after the operations. Using the paired t-test and Pearson's correlation analysis, the postoperative TEA-PCA measured with postoperative CT was compared with theoretical TEA-PCA, which was calculated with preoperative TEA-PCA and actual femoral component rotation checked by the navigation system. RESULTS: After controlling for a relevant confounding variable such as postoperative hip-knee-ankle angle, we found that the extent of medial release (Step 1 as reference; Step 2: odds ratio [OR], 5.7, [95% CI, 2.2-15]; Step 3: OR, 22, [95% CI, 7.8-62], p < 0.001) was the only factor we identified that was associated with internal rotation of the femoral component. With the numbers available, we found no difference between the mean theoretical postoperative TEA-PCA and the postoperative TEA-PCA measured using postoperative CT (4.8° ± 2.7º versus 5.0° ± 2.3º; mean difference, 0.2° ± 1.5º; p = 0.160). CONCLUSIONS: Extent of medial release was the only factor we identified that was associated with internal rotation of the femoral component in gap-balancing TKA. To avoid internal rotation of the femoral component, we recommend a carefully subdivided medial-releasing technique, especially for the superficial MCL because once the superficial MCL has been completely released it cannot easily be restored. LEVEL OF EVIDENCE: Level III, therapeutic study.

Tibial component rotation during the unicompartmental knee arthroplasty: is the anterior superior iliac spine an appropriate landmark?

PURPOSE: No "ideal" landmark for tibial component rotation in medial unicompartmental knee arthroplasty (UKA) has been suggested by a biomechanical and clinical study. The aim of this study was to investigate whether the anterior superior iliac spine (ASIS) could provide a consistent rotational landmark of the tibial component during mobile-bearing medial UKA using computed tomography (CT). METHODS: During sagittal tibial resection, we utilized the ASIS as a rotational landmark. In 47 knees that underwent postoperative CT scans after medial UKA, the tibial component position was assessed by drawing a line tangential to the lateral wall of the tibial component. Rotation of the tibial component was measured using two reference lines: a line perpendicular to the posterior cortical rim of the tibia (angle α) and Akagi's line (angle ß). Instant bearing position and posterior cruciate ligament (PCL) fossa involvement were also evaluated. External rotation of the tibial component relative to each reference line was considered positive values. RESULTS: The mean α and ß angles were 8.0° ± 6.1° (range -4.0 to 24.3) and 8.7° ± 4.8° (range 1.9-25.2), respectively. Fourteen knees (29.8 %) showed PCL fossa involvement of the tibial resection margin. One bearing showed complete 180° rotation at 2 weeks postoperatively. CONCLUSION: Due to the wide variation and inherent difficulty of identifying the ASIS during the operation, it is not recommended for guidance of sagittal tibial resection during medial UKA. In cases of inappropriate tibia component rotation, risk of PE bearing spinning and iatrogenic PCL injury should be reminded after medial UKA. LEVEL OF EVIDENCE: IV.

Sagittal osteotomy inclination in medial open-wedge high tibial osteotomy.

PURPOSE: Unlike postoperative changes in posterior tibial slope after medial open-wedge high tibial osteotomy, sagittal osteotomy inclination has not been examined. It has been recommended that the osteotomy line in the sagittal plane be parallel to the medial posterior tibial slope. The purpose of this study was to determine the frequency of parallel osteotomy in medial open-wedge high tibial osteotomy. METHODS: To determine the sagittal osteotomy inclination, the angle between the medial joint line and the osteotomy line was measured in the lateral radiograph. A positive angle value indicates that the osteotomy is anteriorly inclined relative to the medial posterior tibial slope. Correlation between the sagittal osteotomy inclination and posterior tibial slope was also evaluated. RESULTS: The mean sagittal osteotomy inclination was 15.1 ± 7.5°. The majority 87.1 % of knees showed an anterior-inclined osteotomy. There was a significantly positive correlation between the postoperative posterior tibial slope and the sagittal osteotomy inclination (r, 0.33; 95 % confidence interval (CI) 0.19-0.46; P < 0.001). The postoperative change in posterior tibial slope also showed a significantly positive correlation with the sagittal osteotomy inclination (r, 0.35; 95 % CI 0.21-0.47; P < 0.001). CONCLUSION: Although parallel osteotomy in the sagittal plane relative to the medial joint line was planned, only 12.9 % of cases achieved osteotomy parallel to the medial posterior tibial slope in the sagittal plane. Because of high rate of the anterior-inclined osteotomy and their correlations with posterior tibial slope, surgeons should make all efforts to perform parallel osteotomy relative to medial posterior tibial slope. LEVEL OF EVIDENCE: IV.

Diagnostic Value of Synovial White Blood Cell Count and Serum C-Reactive Protein for Acute Periprosthetic Joint Infection After Knee Arthroplasty.

BACKGROUND: The diagnosis of periprosthetic joint infection (PJI) remains difficult, particularly in acute postoperative stage. The purpose of this study was to investigate the optimal cutoff value of synovial white blood cell (WBC) count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and C-reactive protein (CRP) for diagnosing early postoperative infection after knee joint arthroplasty. METHODS: We retrospectively reviewed primary total knee arthroplasties and unicompartmental knee arthroplasties, with a knee aspiration within 3 weeks of surgery, from January 2006 to November 2016. Twelve infected cases and 185 uninfected cases met the inclusion criteria of our study. We compared the laboratory parameters (synovial WBC count, percentage of polymorphonuclear cells, erythrocyte sedimentation rate, and CRP levels) between the 2 groups. Receiver operating characteristic curves were constructed to determine the optimal cutoff values for each parameter. Each parameter was studied to determine its sensitivity, specificity, and positive and negative predictive values (PPV and NPV) in diagnosing acute PJI. RESULTS: There were 2 optimal cutoff values for synovial WBC count and CRP levels. With the cutoff value of synovial WBC set at 11,200 cells/µL, acute PJI could be diagnosed with the highest sensitivity (100%) and specificity (98.9%); with the cutoff value set at 16,000 cells/µL, the best PPV and NPV were found (100% and 99.5%, respectively). Similarly, the CRP level >34.9 mg/L had the best sensitivity (100%) and specificity (90.3%), whereas the CRP level >74.5 mg/L had the best PPV (100%) and NPV (99.2%). CONCLUSION: Synovial WBC count and CRP levels are useful in diagnosing acute PJI between 1 and 3 weeks after primary knee arthroplasty.

Efficacy and Safety of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Anterior Cruciate Ligament Reconstruction of a Rabbit Model: New Strategy to Enhance Tendon Graft Healing.

PURPOSE: To investigate whether non-autologous transplantation of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) could be integrated safely at the bone-tendon junction without immune rejection and could enhance bone-tendon healing effectively during anterior cruciate ligament (ACL) reconstruction in an animal model. METHODS: ACL reconstructions using hamstring tendons were performed in 30 adult rabbits. The bone tunnels were treated with hUCB-MSCs or were untreated. The specimens were harvested at 4, 8, and 12 weeks. We performed a gross examination of the knee joint; a histologic assessment using H&E staining, as well as immunohistochemical staining, for type II collagen; and an evaluation of bone tunnel widening using micro-computed tomography. RESULTS: No evidence of immune rejection was detected. Tendon-bone healing through Sharpey-like fibers was noticed around tendon grafts at 12 weeks in the control group. A smooth transition from bone to tendon through broad fibrocartilage formation was identified in the treatment group, and the interface zone showed abundant type II collagen production on immunohistochemical staining. Histologic scores for bone-tendon healing were significantly higher in the treatment group at all time points (P < .001). Micro-computed tomography at 12 weeks showed a significantly smaller tibial (P = .029) and femoral (P = .033) bone tunnel enlargement in the treated group than in the control group. CONCLUSIONS: Non-autologous transplantation of hUCB-MSCs was applied in ACL reconstruction without early immune rejection. There was enhanced tendon-bone healing through broad fibrocartilage formation with higher histologic scores and decreased femoral and tibial tunnel widening compared with the control group (79.2% and 80%, respectively, of the control group tunnel area at 12 weeks). CLINICAL RELEVANCE: Non-autologous transplantation of hUCB-MSCs has therapeutic potential in promoting tendon-to-bone healing after ACL reconstruction. Further study in the human model is warranted.

An in Vivo 3D Computed Tomographic Analysis of Femoral Tunnel Geometry and Aperture Morphology Between Rigid and Flexible Systems in Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Transportal Technique.

PURPOSE: The aim of this study was to compare femoral tunnel length, femoral graft-bending angle, posterior wall breakage, and femoral aperture morphologic characteristics between rigid and flexible systems after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using the transportal (TP) technique. METHODS: We evaluated 3-dimensional computed tomography (3D-CT) results for 54 patients who underwent DB ACL reconstruction using the TP technique with either a flexible system (n = 27) or a rigid system (n = 27). The femoral tunnel length, femoral graft-bending angle, posterior wall breakage, femoral tunnel aperture height to width (H:W) ratio, aperture axis angle, and femoral tunnel position were assessed using OsiriX Imaging Software and Geomagic Qualify 2012 (Geomagic, Cary, NC). RESULTS: The mean anteromedial (AM) femoral tunnel length of the flexible group was significantly longer than that of the rigid group (P = .009). The mean femoral graft-bending angles in the flexible group were significantly less acute than those in the rigid group (AM, P < .001; posterolateral [PL], P = .003]. Posterior wall breakage was observed in both groups (P = 1.00). The mean H:W ratios in the rigid group were significantly larger (more elliptical) than those of the flexible group (AM, P < .001; PL, P = .006). The mean aperture axis angle of the PL femoral tunnel in the rigid group was more parallel to the femoral shaft axis than that in the flexible group (P < .001). There were no significant differences in femoral tunnel position between the 2 groups. CONCLUSIONS: The AM femoral tunnel length and the AM/PL femoral graft-bending angle of the flexible system were significantly longer and less acute than those of the rigid system. However, the aperture morphologic characteristics of the AM/PL femoral tunnel and the aperture axis angle of the PL femoral tunnel in the rigid system were significantly more elliptical and closer to parallel to the femoral shaft axis than those of the flexible system. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

High Axial Loads While Walking Increase Anterior Tibial Translation in Intact and Anterior Cruciate Ligament-Deficient Knees.

PURPOSE: To evaluate the effect of high axial loading (AL) on anterior tibial translation (ATT) according to the increase in knee flexion and the effect of valgus stress (VS) and internal rotation (IR) combined with high AL in intact and anterior cruciate ligament (ACL)-deficient knees according to the increase in knee flexion. METHODS: We used 10 fresh-frozen, human cadaveric knees. Different loading conditions (134-N anterior drawer, 1,000-N AL, 10-Nm VS, and 5-Nm IR) were sequentially combined, and ATT was measured at 0°, 15°, 30°, 45°, and 60° of flexion in the intact and ACL-deficient knees. RESULTS: ATT increased significantly by adding high AL in intact knees (P = .001) and ACL-deficient knees (P < .0001) according to the change in flexion angle (P < .0001). Under high AL, ATT in the ACL-deficient knees was significantly larger than that in the intact knees for all loading conditions, and it also increased gradually according to the increase in knee flexion (P = .0001). ATT increased significantly after adding IR or VS with high AL in intact knees (VS, P = .002; VS/IR, P = .03) and ACL-deficient knees (VS, P = .0004) at some of the flexion angles. CONCLUSIONS: The added high AL increased ATT in intact and ACL-deficient knees from 0° to 60° of flexion. The effect of high AL on ATT became greater in ACL-deficient knees than in intact knees, and ATT also gradually increased according to the increase in knee flexion from 0° to 60°. In both the intact and ACL-deficient knees, ATT increased significantly after valgus stress or IR from 0° to 60°. CLINICAL RELEVANCE: ATT during weight bearing increases stress to the ACL, which worsens with valgus stress and/or IR forces. This finding should be considered when one is studying ACL injury mechanisms, as well as prescribing rehabilitation after ACL surgery.

Arthroscopic posteromedial drive-through test in posterior cruciate ligament insufficiency: a new diagnostic test.

PURPOSE: The study investigated the prevalence of the posteromedial drive-through sign in patients undergoing knee arthroscopy and determined its relationship to posterior cruciate ligament (PCL) insufficiency. METHODS: A retrospective review was performed on 1,015 patients undergoing knee arthroscopy from 2009 to 2012 at two institutions. During knee arthroscopy, the ability to pass the arthroscope easily between the medial femoral condyle and the PCL is considered a positive posteromedial drive-through sign. We calculated the accuracy, sensitivity, specificity, positive predictive value and negative predictive value of posteromedial drive-through sign for diagnosis of PCL ruptures. The posterior laxity measured by Telos stress radiograph was compared between the posteromedial drive-through sign (+) and (-) patients with PCL ruptures. RESULTS: Of the 1,015 patients, 73 (7 %) had a positive posteromedial drive-through sign. For the diagnosis of PCL rupture, a posteromedial drive-through sign had an overall accuracy of 97.6 %, sensitivity of 78.8 %, specificity of 99.3 %, positive predictive value of 91.7 % and negative predictive value of 98.1 %. For the ligament laxity examination using stress radiographs, the mean posterior tibia translation was 13.8 ± 2.2 mm, while the mean posterior translation was 10.6 ± 2.4 mm in those with a negative posteromedial drive-through sign (p < 0.05). There was no relationship between a positive posteromedial drive-through sign and age and combined injuries (n.s.). CONCLUSION: A positive posteromedial drive-through sign strongly indicates the presence of PCL injuries and this arthroscopic sign is highly associated with grade III posterior knee instability. LEVEL OF EVIDENCE: III.

Comparison of Achilles and tibialis anterior tendon allografts after anterior cruciate ligament reconstruction.

PURPOSE: The purpose of this study was to compare the outcomes after anterior cruciate ligament (ACL) reconstruction using Achilles tendon allografts and tibialis anterior (TA) tendon allografts with respect to objective knee testing measures, second-look arthroscopy and femoral tunnel enlargement. METHODS: A total of 131 patients who underwent ACL reconstruction between 2000 and 2006 were retrospectively reviewed. Achilles tendon allografts were used in 81 patients (group I). These patients were compared with 50 patients in whom TA tendon allografts were used (group II). The two groups were assessed using International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores, as well as KT-2000 testing. Second-look arthroscopic findings were evaluated. Cross-sectional area (CSA) perpendicular to the long axis of the femoral tunnel was also calculated digitally using magnetic resonance imaging. RESULTS: No significant differences were observed between the two groups with respect to IKDC, Lysholm or Tegner activity scores or the results of laxity testing with arthrometry. Synovial coverage of more than 50 % was found in 71.1 % cases in group I and 75 % cases in group II. Mean CSA enlargement of 15 % (group I) and 38 % (group II) was detected (p = 0.017). CONCLUSIONS: The clinical results associated with Achilles and TA tendons were not significantly different. The laxity evaluation and second-look arthroscopy demonstrated no significant differences between group I and group II. However, Achilles tendon-bone plugs for femoral tunnel fixation reduced femoral tunnel enlargement compared to the TA allograft. Achilles tendon allografts for ACL reconstruction could be a reasonable option in selected patients.

Impact of patellar height on unicompartment knee arthroplasty: does patella baja lead to an inferior outcome?

BACKGROUND: Though a number of series with long-term results have been published, there is still a paucity of literature on the role of patellar height after unicompartment knee arthroplasty (UKA). The present study was conducted with a hypothesis that patella baja may lead to a poor outcome at follow-up. MATERIALS AND METHODS: A retrospective review of 134 knees was performed and patellar height calculated before and after UKA by Blackburne-Peel index (BPI) and the Insall-Salvati ratio (ISR) on true lateral radiographs of the patients in 30° of flexion taken pre-operatively and at 1 year, 2 years and final follow-up (minimum 5 years). Statistical analysis was performed to evaluate the outcomes. RESULTS: There was a decrease in ISR in 14.18 % and in BPI in 19.4 % at final follow-up. There was a significant decrease in BPI values while the decrease was not significant for ISR. After eliminating the pre-operative patella baja, 7.3 % developed post-operative patella baja, according to ISR, while 11.5 % developed patella baja as per BPI. At final follow-up there was a statistically significant decrease in stair climbing scores in patients with patella baja when compared to patients with normal ISR. CONCLUSION: Patients with a decrease in patellar height as per ISR have a decrease in stair climbing score at mid-term follow-up while the overall KSS, and pain scores are not affected by a change in patellar height and neither is there a significant progress in patellofemoral osteoarthritis among patients with patella baja compared to normal patella.

Comparison of femoral tunnel length between transportal and retrograde reaming outside-in techniques in anterior cruciate ligament reconstruction.

PURPOSE: To evaluate the accuracy of intraoperative femoral tunnel length measurement and to compare this between the transportal (TP) and outside-in (OI) techniques for double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. METHODS: Eighty patients underwent a DB ACL reconstruction using either the TP or the OI technique. The participants were randomized to either a TP group (I, 40 cases) or a OI group (II, 40 cases). The intraoperatively measured femoral tunnel length was recorded, and the postoperative femoral tunnel length was measured using computed tomography with OsiriX(®) imaging software. RESULTS: The mean femoral tunnel lengths measured intraoperatively in Group II (38.9 ± 3.0 mm for anteromedial [AM], 39.3 ± 3.4 mm for posterolateral [PL]) were significantly longer than those of Group I (34.8 ± 2.7 mm for AM, 36.0 ± 3.2 mm for PL) (P < 0.001). The mean AM femoral tunnel length measured postoperatively in Group II (33.3 ± 3.8 mm) was significantly longer than that in Group I (31.1 ± 2.9 mm) (P = 0.006). The mean intraoperatively measured femoral tunnel length was significantly longer than that measured postoperatively in Groups I and II (P < 0.001). CONCLUSION: After anatomic DB ACL reconstruction, the femoral tunnel length of the OI technique measured intraoperatively (AM/PL) and postoperatively (AM) was longer than those of the TP technique. The femoral tunnel length measured intraoperatively was longer than that measured postoperatively in both TP and OI technique. This study may help surgeons to measure femoral tunnel length accurately in anatomic DB ACL reconstruction with suspensory fixation device.

Postoperative femoral component rotation and femoral anteversion after total knee arthroplasty in patients with distal femoral deformity.

We asked whether total knee arthroplasty (TKA) in patients with distal femoral deformity (DFD) would change femoral component rotation (FCR) and investigated the correlation between DFD and femoral anteversion (FA). 75 patients were divided into two groups according to the preoperative posterior condylar angle (PCA); group A without DFD (PCA<7°), group B with DFD (PCA>7°). We evaluated the different angles on the CT scan: (1) PCA, (2) angle between the line which is perpendicular to the Whiteside's line and PCL (WLP), and (3) FA. The mean FCRs were external rotation of 0.21°+2.75° in group A and internal rotation of 4.48°+2.51° in group B (P=0.001). The mean preoperative and postoperative FAs were similar in group A but were significantly different in group B (P=0.035). DFD resulted in excessive internal rotation of the femoral component. There was a secondary decrease in FA in patients with DFD.

Cost Effectiveness of Allogeneic Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Patients with Knee Osteoarthritis.

OBJECTIVES: The aim of this study was to assess the cost effectiveness of allogeneic umbilical cord blood-derived mesenchymal stem cells with sodium hyaluronate (hUCB-MSC) compared with microfracture in patients with knee cartilage defects caused by osteoarthritis (OA) in South Korea. METHODS: A partitioned survival model approach was taken consisting of five mutually exclusive health states: excellent, good, fair, poor, and death over a 20-year time horizon. Utility values were obtained from a randomized clinical trial. Cost data were extracted from a database provided by the Health Insurance Review & Assessment Service, and the utilization of healthcare services was estimated from an expert panel of orthopedic surgeons using a structured questionnaire. The incremental cost-effectiveness ratio (ICER) in terms of quality-adjusted life-years (QALY) was calculated. Deterministic and probabilistic sensitivity analyses were performed. RESULTS: In the base case, the incremental costs of US$14,410 for hUCB-MSC therapy along with its associated QALY gain of 0.857 resulted in an ICER of US$16,812 (₩18,790,773) per QALY (95% confidence interval [CI] US$13,408-US$20,828) when compared with microfracture treatment from a healthcare payer perspective. From a societal perspective, the ICER was US$268 (₩299,255) per QALY (95% CI -US$2915 to US$3784). When using a willingness-to-pay threshold of US$22,367/QALY, the probability of hUCB being cost effectiveness compared with microfracture was 99% from the healthcare payer perspective and 100% from the societal perspective. CONCLUSIONS: The study demonstrated that hUCB-MSC therapy was cost effective compared with microfracture when treating patients with knee OA. These findings should inform health policy decision makers about considerations for cost-effective therapy for treating knee OA to ultimately enhance population health.

Repair of rabbit ulna segmental bone defect using freshly isolated adipose-derived stromal vascular fraction.

BACKGROUND AIMS: Stromal vascular fractions (SVF) from adipose tissue have heterogeneous cell populations, and include multipotent adipose-derived stem cells. The advantages of using of SVF include the avoidance of an additional culture period, a reduced risk of extensive cell contamination, and cost-effectiveness. METHODS: Unilateral 20-mm mid-diaphyseal segmental defects in rabbit ulna were treated with one of the following: polylactic glycolic acid (PLGA) scaffold alone (group 1, control), a PLGA scaffold with undifferentiated SVF cells (group 2), or a PLGA scaffold with osteogenically differentiated SVF cells (group 3). At 8 weeks after implantation, five rabbits in each treatment group were killed to assess bone defect healing by plain radiography, quantitative microcomputed tomography and histology. RESULTS: The SVF cells were well grown on PLGA scaffolds and expressed type I collagen and alkaline phosphatase (ALP). The intensity of ALP and OPN gene expressions in osteogenic medium culture were increased from 14 days to 28 days. In vivo evaluations at 8 weeks showed that treatment of SVF cells with or without osteogenic differentiation resulted in more bone formation in the critically sized segmental defects than PLGA scaffold alone. Osteogenically differentiated SVF cells significantly enhanced bone healing compared with undifferentiated SVF cells. CONCLUSIONS: Adipose-derived stromal SVF showed osteogenic potential in vitro. Accordingly, SVF could provide a cell source for bone tissue engineering. However, treatment with uncultured SVF cells on bone healing was not satisfactory in the in vivo animal model.

Current treatments of isolated articular cartilage lesions of the knee achieve similar outcomes.

BACKGROUND: Many surgical techniques, including microfracture, periosteal and perichondral grafts, chondrocyte transplantation, and osteochondral grafts, have been studied in an attempt to restore damaged articular cartilage. However, there is no consensus regarding the best method to repair isolated articular cartilage defects of the knee. QUESTIONS/PURPOSES: We compared postoperative functional outcomes, followup MRI appearance, and arthroscopic examination after microfracture (MF), osteochondral autograft transplantation (OAT), or autologous chondrocyte implantation (ACI). METHODS: We prospectively investigated 30 knees with MF, 22 with OAT, and 18 with ACI. Minimum followup was 3 years (mean, 5 years; range, 3-10 years). We included only patients with isolated cartilage defects and without other knee injuries. The three procedures were compared in terms of function using the Lysholm knee evaluation scale, Tegner activity scale, and Hospital for Special Surgery (HSS) score; modified Outerbridge cartilage grades using MRI; and International Cartilage Repair Society (ICRS) repair grade using arthroscopy. RESULTS: All three procedures showed improvement in functional scores. There were no differences in functional scores and postoperative MRI grades among the groups. Arthroscopy at 1 year showed excellent or good results in 80% after MF, 82% after OAT, and 80% after ACI. Our study did not show a clear benefit of either ACI or OAT over MF. CONCLUSIONS: Owing to a lack of superiority of any one treatment, we believe MF is a reasonable option as a first-line therapy given its ease and affordability relative to ACI or OAT. LEVEL OF EVIDENCE: Level II, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Long-term results of anterior cruciate ligament reconstruction using bone-patellar tendon-bone: an analysis of the factors affecting the development of osteoarthritis.

PURPOSE: To evaluate the clinical outcomes and incidence of knee osteoarthritis (OA) and the factors associated with the onset of OA in the 3 compartments of the knee joint separately after anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone autograft. METHODS: Clinical and radiologic assessments were obtained from 117 patients (80.1%). At follow-up, knee function was evaluated with the Lysholm score, Hospital for Special Surgery (HSS) score, Tegner score, and International Knee Documentation Committee (IKDC) 2000 forms. We also evaluated stability and donor-site morbidity. On the follow-up radiographs, OA was assessed by IKDC grading. The factors affecting the onset of OA in the 3 compartments of the knee joint were evaluated. RESULTS: The mean follow-up period was 10.3 ± 1.0 years. The mean Lysholm and HSS scores significantly increased at final follow-up (P < .001). The mean IKDC subjective score was 90.6, and 93.9% of patients had grade A or grade B knees on the objective evaluation. The mean side-to-side difference measured by KT-2000 arthrometer (MEDmetric, San Diego, CA) was 1.6 ± 1.7 mm, with 82.0% of patients showing a difference of less than 3 mm. Discomfort from knee walking on hard ground and skin numbness were reported by 38.4% and 37.6% of patients, respectively. OA developed in the medial, lateral, and patellofemoral compartments in 30.7%, 9.3%, and 7.6% of patients, respectively. The onset of OA was associated with partial meniscectomy (odds ratio [OR], 20.73; P = .005) or sagittal tibial tunnel position (OR, 1.18; P = .02) in the medial compartment and body mass index (BMI) (OR, 1.56; P = .02) in the lateral compartment. CONCLUSIONS: ACL reconstruction with bone-patellar tendon-bone autograft showed satisfactory clinical results after a mean of 10.3 years. However, pain when walking on hard ground (38.4%) and numbness of the skin (37.6%) were reported. Moreover, the onset of OA appeared in over 40% of the patients. The onset of OA in the medial compartment was correlated with partial meniscectomy and sagittal tibial tunnel position, and the onset of OA in the lateral compartment was correlated with higher BMI. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Femoral graft bending angle and femoral tunnel geometry of transportal and outside-in techniques in anterior cruciate ligament reconstruction: an in vivo 3-dimensional computed tomography analysis.

PURPOSE: To compare femoral graft bending angles and femoral tunnel geometries between the transportal (TP) and outside-in (OI) techniques after anatomic double-bundle (DB) anterior cruciate ligament (ACL) reconstruction. METHODS: Thirty-nine patients underwent DB ACL reconstruction with the TP and OI techniques. They were randomized on the day of surgery to either the TP group (group I, 21 cases) or the OI group (group II, 18 cases). Femoral graft bending angle, femoral tunnel geometry, posterior wall breakage, and tunnel communication were assessed by computed tomography imaging with OsiriX imaging software (Pixmeo, Geneva, Switzerland). RESULTS: The mean anteromedial (AM) and posterolateral (PL) femoral graft bending angles of group II (97.3° ± 8.3° and 97.4° ± 8.6°, respectively) were significantly more acute than those of group I (108.2° ± 8.4° and 109.9° ± 8.8°, respectively) (P < .001). The mean AM femoral tunnel length of group II (34.3 ± 3.9 mm) was significantly longer than that of group I (31.9 ± 2.7 mm) (P = .02). However, the mean PL femoral tunnel lengths did not differ between groups. In 7 cases-4 cases (19.0%) in group I and 3 cases (16.6%) in group II-the femoral tunnel communication was found around the intra-articular aperture. Posterior wall breakage was observed in 5 cases (23.8%), which were all in AM femoral tunnels of group I. CONCLUSIONS: The OI technique resulted in more acute femoral graft bending angles (difference of 10.9° and 12.5° for AM and PL, respectively) and longer mean AM femoral tunnel lengths (difference of 2.4 mm) than the TP technique after anatomic DB ACL reconstruction, even though these small differences might be unlikely to be of clinical significance. Femoral tunnel communication was found in both groups, and posterior wall breakage was observed in AM femoral tunnels with the TP technique. LEVEL OF EVIDENCE: Level I, prospective randomized trial.

Incidence of bilateral discoid lateral meniscus in an Asian population: an arthroscopic assessment of contralateral knees.

PURPOSE: To investigate the incidence of bilateral discoid lateral meniscus (DLM) and to evaluate the arthroscopic features of lateral meniscus in asymptomatic contralateral knees in an Asian population who presented with symptomatic DLMs. METHODS: This study prospectively enrolled 52 consecutive patients who underwent arthroscopic procedures for symptomatic DLMs (31 complete and 21 incomplete) and who consented to the examination of the contralateral knee at the time of arthroscopy. Types of DLMs and of meniscus tears were assessed by use of arthroscopic findings. Preoperative and postoperative functional outcomes were evaluated with Lysholm and Tegner activity scores. RESULTS: Arthroscopic examinations showed 21 complete DLMs, 19 incomplete DLMs, 11 normal lateral menisci, and 1 ring-shaped lateral meniscus in contralateral knees. The incidence of bilateral DLM in our study population was 79% (41 of 52 contralateral knees). Furthermore, 65% of patients (34 pairs of knees) had the same DLM types. In addition, 3 pairs of knees with complete DLMs had menisci of different thicknesses. DLM tears were observed in 2 contralateral knees (1 radial and 1 longitudinal) and were treated by partial central meniscectomy. CONCLUSIONS: This study provides evidence of the high prevalence of bilateral DLM in an Asian population.