Second-Look Arthroscopic Findings and Clinical Outcomes after Adipose-Derived Regenerative Cell Injection in Knee Osteoarthritis.

Background: To evaluate the clinical outcomes and second-look arthroscopic findings after intra-articular adipose-derived regenerative cell (ADRC) injection as treatment for knee osteoarthritis (OA). Methods: ADRCs were administered to 11 patients (19 knees; mean age, 61.7 years) with knee OA. Subcutaneous adipose tissue was harvested by liposuction from both thighs, and arthroscopic lavage was performed, followed by ADRC injection (mean dose, 1.40 × 107 cells) into the synovial fluid. Outcome measures included the Knee Injury and Osteoarthritis Outcome Score, Lysholm score, and visual analog scale score. Arthroscopic examinations were performed to assess the International Cartilage Repair Society cartilage injury grade preoperatively and overall repair postoperatively. Noninvasive assessments were performed at baseline and at 1-, 3-, and 6-month follow-ups; arthroscopic assessments were performed at baseline and at 6 months. Results: All outcome measures significantly improved after treatment. This improvement was evident 1 month after treatment and was sustained until the 6-month follow-up. Data from second-look arthroscopy showed better repair in low-grade cartilage lesions than in lesions with a greater degree of damage. No patients demonstrated worsening of Kellgren-Lawrence grade, and none underwent total knee arthroplasty during this period. Conclusions: Clinical outcomes were improved in patients with knee OA after ADRC administration. Cartilage regeneration was more effective in smaller damaged lesions than in bigger lesions.

Validation of the Macroscopic Anterior Cruciate Ligament Status Using the Oxford Classification System in Relation to Cartilage Defects on the Medial Tibial Plateau in Osteoarthritic Knees.

This study evaluated the relationships between anterior cruciate ligament (ACL) grading using the Oxford classification system and cartilage defects on the medial tibial plateau to clarify the validity of the system. We studied the location and size of a full-thickness cartilage defect of the medial tibial plateau in 154 knees (97 patients) treated by unicompartmental (113) or total (41) knee arthroplasty between April 2017 and January 2018, and analyzed their relationship to the anterior cruciate ligament (ACL) grade, Grade 1 (normal), Grade 2 (synovial damage), Grade 3 (longitudinal split), Grade 4 (friable and fragmented), and Grade 5 (absent). Significant trends in decreased posterior preserved cartilage, increased defect length, and posteriorized defect center were associated with increasing ACL grade. Multiple comparison analysis revealed that the measurements were significantly different between ACL functional (Grades 1-3) and ACL deficient (Grades 4 and 5). On the other hand, the anterior preserved cartilage was consistent among the Grades. The macroscopic Oxford ACL classification system well described the disease progression where the cartilage defect extends posteriorly with ACL damage. However, 38% of ACL deficient knees had well-preserved posterior cartilage with no evident tibial anterior translation.

Lateral osteoarthritis progression is associated with a postoperative residual tibiofemoral subluxation in Oxford UKA.

PURPOSE: Lateral compartment osteoarthritis progression (LOP) is a major complication after Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study aimed to identify the association between tibiofemoral subluxation (TFS) and LOP after OUKA. Patients whose TFS was uncorrectable according to preoperative stress radiographs were hypothesised to develop residual TFS even after surgery, and thought to be more likely to develop LOP. METHODS: The study included 201 patients who underwent medial OUKA. Fifteen patients showed increases in LOP of at least two Kellgren-Lawrence grades after surgery [progression (P) group], while the others had no progression (N group, n = 186). TFS was measured on preoperative full leg weight-bearing radiographs, valgus stress radiographs and postoperative plain radiographs. Valgus stress radiographs were obtained using a firm manual valgus force with the knee flexed at 20°. Leg alignment, Oxford knee score (OKS), and revision rates were assessed. RESULTS: The P group had significantly higher TFS values on preoperative valgus stress (6.8° ± 2.2° vs. 4.5° ± 2.0°; P < 0.001) and postoperative radiographs (6.6° ± 2.3° vs. 4.6° ± 2.9°; P < 0.001) than the N group. Patients with postoperative residual TFS and postoperative valgus alignment were more likely to have LOP, but 9 of the 15 LOP patients did not show postoperative valgus alignment. The P group had significantly poorer postoperative OKS (33.0 ± 10.2 vs. 37.4 ± 6.5, P = 0.017) and a higher rate of revision (6/15 vs 6/186; odds ratio = 19.16; 95% CI = 4.98-76.05, P < 0.001). CONCLUSION: OA progression in the lateral compartment after medial OUKA might be associated with postoperative residual TFS, but does not always coexist with postoperative valgus alignment. Preoperative assessment of TFS with valgus stress could be a potential predictor of postoperative residual TFS and LOP. LEVEL OF EVIDENCE: Level III.

CLINICAL OUTCOMES AFTER UNICOMPARTMENTAL KNEE ARTHROPLASTY FOR OSTEONECROSIS OF THE KNEE.

OBJECTIVE: Although the mobile-bearing Oxford unicompartmental knee arthroplasty (OUKA) seems an appropriate procedure to treat spontaneous osteonecrosis of the knee (SONK), aseptic tibial component loosening was the leading cause for medial UKA failure. This study aimed to observe short-term and midterm clinical outcomes following OUKA and determine whether tibial lesion affects the procedure clinical and radiographic outcomes. METHODS: Sixty patients (mean age 73.1 ± 6.6 years) diagnosed with SONK in the medial femoral condyle and treated with OUKA were separated into two groups using T1-weighted preoperative magnetic resonance imaging (MRI): group F (necrotic lesion confined to the femur) and group T (necrotic lesion spread to the tibia). The Oxford Knee Score (OKS), maximum flexion angle (MFA), and radiographic findings (radiolucent line and subsidence) were compared between the two groups using unpaired t-test. RESULTS: Both groups showed significant improvement in OKS and MFA values at the final follow-up, but without significant differences in the clinical and radiographic outcomes. CONCLUSION: OUKA is a reliable treatment procedure for SONK in the short and midterm. The presence of tibial lesions on preoperative MRI does not affect postoperative radiographic and clinical outcomes. Level of Evidence IV, Case Series.

OBJETIVO: Embora a Artroplastia Unicompartimental do Joelho (AUJ) de Oxford pareça ser um procedimento adequado para o tratamento da Osteonecrose Espontânea do Joelho (ONEJ), o afrouxamento asséptico do componente tibial foi a principal causa de fracassos na AUJ medial. Este estudo teve por objetivo observar desfechos clínicos de curto e médio prazo após AUJ, além de determinar se a presença de lesão tibial interfere nos desfechos clínicos e radiográficos do procedimento. MÉTODOS: Sessenta pacientes (idade média de 73,1 ± 6.6 anos) diagnosticados com ONEJ no côndilo medial do fêmur e tratados com AUJ foram divididos em dois grupos por meio de imagens ponderadas em T1 obtidas em exames pré-operatórios de ressonância magnética (RM): grupo F (lesão necrótica limitada ao fêmur) e grupo T (lesão necrótica espalhada para a tíbia). Os valores obtidos no Oxford Knee Score (OKS) e o ângulo de flexão máxima (AFM), bem como achados radiográficos (linha radiotransparente e subsidência) para cada grupo foram comparados usando teste t não-pareado. RESULTADOS: Ambos os grupos apresentaram melhoria significativa nos valores de OKS e AFM no último acompanhamento, mas sem diferenças significativas nos desfechos clínicos e radiográficos. CONCLUSÃO: AUJ é um procedimento confiável para o tratamento de ONEJ a curto e médio prazo. A presença de lesões da tíbia, diagnosticada por meio da RM pré-operatória, não afetou os desfechos clínicos e radiográficos no pós-operatório. Nível de Evidência IV, Série de casos.

Clinical outcomes after unicompartmental knee arthroplasty for osteonecrosis of the knee / Desfechos clínicos após artroplastia unicompartimental do joelho no tratamento da osteonecrose do joelho

ABSTRACT Objective: Although the mobile-bearing Oxford unicompartmental knee arthroplasty (OUKA) seems an appropriate procedure to treat spontaneous osteonecrosis of the knee (SONK), aseptic tibial component loosening was the leading cause for medial UKA failure. This study aimed to observe short-term and midterm clinical outcomes following OUKA and determine whether tibial lesion affects the procedure clinical and radiographic outcomes. Methods: Sixty patients (mean age 73.1 ± 6.6 years) diagnosed with SONK in the medial femoral condyle and treated with OUKA were separated into two groups using T1-weighted preoperative magnetic resonance imaging (MRI): group F (necrotic lesion confined to the femur) and group T (necrotic lesion spread to the tibia). The Oxford Knee Score (OKS), maximum flexion angle (MFA), and radiographic findings (radiolucent line and subsidence) were compared between the two groups using unpaired t-test. Results: Both groups showed significant improvement in OKS and MFA values at the final follow-up, but without significant differences in the clinical and radiographic outcomes. Conclusion: OUKA is a reliable treatment procedure for SONK in the short and midterm. The presence of tibial lesions on preoperative MRI does not affect postoperative radiographic and clinical outcomes. Level of Evidence IV, Case Series.

RESUMO Objetivo: Embora a Artroplastia Unicompartimental do Joelho (AUJ) de Oxford pareça ser um procedimento adequado para o tratamento da Osteonecrose Espontânea do Joelho (ONEJ), o afrouxamento asséptico do componente tibial foi a principal causa de fracassos na AUJ medial. Este estudo teve por objetivo observar desfechos clínicos de curto e médio prazo após AUJ, além de determinar se a presença de lesão tibial interfere nos desfechos clínicos e radiográficos do procedimento. Métodos: Sessenta pacientes (idade média de 73,1 ± 6.6 anos) diagnosticados com ONEJ no côndilo medial do fêmur e tratados com AUJ foram divididos em dois grupos por meio de imagens ponderadas em T1 obtidas em exames pré-operatórios de ressonância magnética (RM): grupo F (lesão necrótica limitada ao fêmur) e grupo T (lesão necrótica espalhada para a tíbia). Os valores obtidos no Oxford Knee Score (OKS) e o ângulo de flexão máxima (AFM), bem como achados radiográficos (linha radiotransparente e subsidência) para cada grupo foram comparados usando teste t não-pareado. Resultados: Ambos os grupos apresentaram melhoria significativa nos valores de OKS e AFM no último acompanhamento, mas sem diferenças significativas nos desfechos clínicos e radiográficos. Conclusão: AUJ é um procedimento confiável para o tratamento de ONEJ a curto e médio prazo. A presença de lesões da tíbia, diagnosticada por meio da RM pré-operatória, não afetou os desfechos clínicos e radiográficos no pós-operatório. Nível de Evidência IV, Série de casos.

Impact of joint line orientation on clinical outcomes in bilateral Oxford mobile-bearing unicompartmental knee arthroplasty.

BACKGROUND: Joint line orientation angle (JLOA) is the angle between the knee joint line and the floor. It has been reported to be related to postoperative outcome after TKA. Regarding unicompartmental knee arthroplasty (UKA), although it can be horizontal after UKA because it is a resurfacing surgery, there are few reports about the JLOA after UKA and its impact on clinical outcomes. PURPOSE: The purpose of this study was to reveal the relationship between JLOA and clinical outcome after UKA. METHODS: This study included 106 knees in 53 consecutive patients with osteoarthritis who underwent simultaneous bilateral mobile-bearing UKA. Their pre- and postoperative JLOAs were measured by full-leg-length standing coronal radiographs. We also evaluated the tibial component height (TCH) as the factor which we assumed could influence JLOA. We analyzed the patients' JLOAs, TCHs and clinical outcomes. RESULTS: Pre- and postoperative JLOA were 0.4 ± 2.4° and 2.7 ± 2.6°, respectively. The JLOA significantly tilted medially (P < 0.0001). The JLOA significantly negatively correlated with the improvement of the clinical outcomes (Oxford Knee Score (OKS): r = 0.40, P < 0.0001, Knee Society Knee Score (KSKS): r = 0.25, P < 0.01, Knee Society Function Score (KSFS): r = 0.22, P = 0.02). The TCH showed a positive correlation with postoperative JLOA and with the postoperative JLOA change (r = 0.45, P < 0.001; r = 0.25, P < 0.01, respectively). CONCLUSION: The JLOA significantly tilted medially after UKA. An excessive medial tilt of the JLOA was associated with poorer postoperative outcomes of UKA. It is therefore recommended to keep the JLOA horizontal and to avoid a lower tibial cut.

Anterior Cruciate Ligament Deficiency is Not Always a Contraindication for Medial Unicompartmental Knee Arthroplasty: A Retrospective Study in Nondesigner's Japanese Hospital.

BACKGROUND: An intact anterior cruciate ligament (ACL) is thought to be prerequisite for successful unicompartmental knee arthroplasty (UKA), but recent studies reported successful midterm results of UKA in ACL-deficient (ACLD) knees. We hypothesized that ACLD is not always a contraindication for medial UKA when preoperative radiographs showed typical anteromedial knee patterns. METHODS: From April 2012 to March 2016, 401 Oxford mobile-bearing UKAs in 282 patients were retrospectively identified from our database. Patients whose ACL was severely damaged, but preoperative X-rays showed typical anteromedial osteoarthritis patterns, were categorized into the ACLD group. From intraoperative data, those whose ACL was intact were categorized into the ACL functional (ACLF) group. There were 32 and 369 knees in the ACLD and ACLF groups, respectively, and mean follow-up periods were 66.1 and 63.8 months for the ACLD and ACLF groups, respectively. We compared the postoperative clinical outcome and component survivorship, with an endpoint of component revision, between ACLD groups and ACLF groups. RESULTS: In both groups, the Oxford knee score, Knee Society score, Tegner activity score, and knee range of motion in extension were improved after surgery. The UKA component survival rate at five years was 100% in the ACLD group and 98.9% in the ACLF group. There were no significant differences between the groups. CONCLUSION: Mid-term clinical outcomes of Oxford mobile-bearing UKA in ACLD knees were similar to those in ACLF knees. ACL deficiency is not always a contraindication for medial unicompartmental knee arthroplasty in patients with typical anteromedial osteoarthritis radiographs.

Extent of in vivo sagittal bearing movement and its relationship with tibial posterior slopes in Oxford mobile-bearing unicompartmental knee arthroplasty.

BACKGROUND: The effect of increased tibial slope on the bearing movement and clinical results in mobile-bearing unicompartmental knee arthroplasty has not been well discussed. We aimed to clarify the extent of in vivo sagittal bearing movement and bearing overhang using fluoroscopy and their relationship with the tibial posterior slopes and clinical results. METHODS: This retrospective study included 40 patients who underwent Oxford unicompartmental knee arthroplasty for anteromedial osteoarthritis or osteonecrosis of the knee. Intraoperative posterior translation and posterior overhang of the bearing were assessed during flexion. The tibial posterior slopes were evaluated before and 2 weeks after surgery, and its increment was recorded. Clinical evaluations were also performed preoperatively and at 2 years postoperatively (maximum flexion angle, Oxford Knee Score). Single linear regression analysis was performed to assess the correlation between the tibial posterior slopes and the posterior translation and the posterior overhang and determine if these could affect the clinical outcomes. FINDINGS: The average posterior translation was 10.7 ± 4.3 mm, and posterior overhang of the mobile bearing was found in 35% of overall patients. They were associated with increased tibial slope as well as poorer improvement in Oxford Knee Score at 2 years postoperatively. INTERPRETATION: In Oxford unicompartmental knee arthroplasty, mobile bearing can probably move posteriorly beyond the posterior margin of the tibial component during flexion when the tibial posterior slope increases more than the original magnitude. Additionally, the posterior translation and posterior overhang closely correlated with the poorer improvement in Oxford Knee Score at 2 years postoperatively.

The Medial Eminence Line for Predicting Tibial Fracture Risk after Unicompartmental Knee Arthroplasty.

BACKGROUD: Tibial fracture after cementless Oxford unicompartmental knee arthroplasty (OUKA) is a rare but serious complication. It is reported more frequently in Asian countries. The aim of this retrospective study was to assess the morphological characteristics of the tibia by using a simple novel measurement method in patients with tibial fractures after OUKA. METHODS: Six knees (all women) with tibial fractures after cementless OUKA (fracture group) and 150 knees without an obvious complication after cementless OUKA (control group) were examined retrospectively at our institution between January 2016 and April 2017. We drew a medial eminence line (ME line) defined as a line extending from the tip of the medial intercondylar eminence parallel to the tibial axis. The ME line was classified into two types (intramedullary type [type I] and extramedullary type [type E]), and the proportion of each type was compared between fracture patients and controls. RESULTS: In the fracture group, there were four (66.7%) type E cases and two (33.3%) type I cases; in the control group, there were 18 (12%) type E cases and 132 (88%) type I cases. Fisher exact tests showed that the proportion of type E was higher in the fracture group than in the control group (p < 0.01). CONCLUSIONS: Measurement of the ME line can be recommended as a useful method to assess the risk of postoperative fracture after cementless OUKA.

Morphometric analysis of medial and lateral tibia plateau and adaptability with Oxford partial knee replacement in a Japanese population.

AIMS: In unicompartmental knee arthroplasty (UKA), tibial components must be correctly sized and positioned so that tibial cut surfaces are well covered without marked under- or overhang with impingement of the surrounding soft tissue. We used morphometric data of both medial and lateral tibial plateaus separately to plan UKA and evaluated the compatibility of the measurement data to the dimensions of six currently available tibial prostheses in a Japanese population. MATERIALS AND METHODS: Using computed tomography, we preoperatively examined 60 patients (30 medial and 30 lateral osteoarthritis (OA)) scheduled for primary UKA at our hospital between 2013 and 2017. Each tibial cutting surface was measured in the transverse plane at 2 mm below the respective joint line. We used anteroposterior and mediolateral length to calculate the mediolateral length/anteroposterior ratio of both medial and lateral compartments. We then compared measurements across six current UKA systems: Oxford fixed tibia and fixed lateral tibia, Triathlon, TRIBRID, JOURNEY UNI, and HLS Uni Evolution. RESULTS: We found no significant differences in morphometric data between the medial and the lateral OA. The cutting surface of lateral plateau, however, had smaller anteroposterior dimensions, greater mediolateral length, and higher mediolateral length/anteroposterior ratio than those of medial plateau. Therefore, in this Japanese population-based study, Oxford lateral tibia had good compatibility with the measurement data of lateral compartments. CONCLUSIONS: Lateral compartments had lower anteroposterior length, greater mediolateral length, and higher mediolateral length/anteroposterior ratio than those of medial compartments. We, therefore, strongly recommend using Oxford fixed lateral tibia for lateral OA over other current tibial prostheses because of superior coverage.

Approximately 30% of Functioning Anterior Cruciate Ligaments Are Sacrificed for Knee Arthroplasty.

The anterior cruciate ligament (ACL) plays an important role in knee kinematics. Unicompartmental knee arthroplasty (UKA) preserves the ACL, an advantage over total knee arthroplasty (TKA), where it is sacrificed. This study aims to evaluate how often functional ACLs are sacrificed in arthroplasty. The type of arthroplasty (TKA or UKA) and condition of the ACL were studied in a total of 1,586 knees in 1,052 patients who underwent knee arthroplasties. Of 1,586 knees, TKA was performed on 653 knees (41%) and UKA on 933 knees (59%). The ACL was functioning in 77% of all knees. Of the TKA knees, the ACL was functioning in 357 knees (55%). Of these, around 30% of the functioning ACLs were sacrificed to perform TKA. To improve postoperative patient satisfaction after knee arthroplasty, further study regarding relationship between ACL preservation and clinical outcome will be required.

Second-look arthroscopic findings of cartilage and meniscus repair after injection of adipose-derived regenerative cells in knee osteoarthrits: Report of two cases.

BACKGROUND: The purpose of this study was to use second-look arthroscopic findings and clinical assessment to determine outcome in two cases of knee osteoarthritis treated by intra-articular knee injection of adipose-derived regenerative cells (ADRCs). CASE PRESENTATION: This study involved two patients who received ADRC therapy for knee osteoarthritis and completed the six-month post-treatment follow-up period. For each treatment, 130 mL of subcutaneous adipose tissue was harvested using tumescent liposuction technique and manual aspiration of tissue from the thigh using a suction cannula under local anesthesia in the operating room. The adipose tissue harvested was processed using the Celution® Centrifuge in a dedicated cell processing room. The ADRCs were injected into the articular cavity of both knees for one patient and into a single affected knee in the second patient (three joints). Pain and knee function were assessed using a Visual Analogue Scale (VAS) and the Knee Outcome in Osteoarthritis Score (KOOS) respectively. The cartilage defect was assessed by direct visualization (arthroscopy). No serious adverse events were reported throughout follow-up. Pain and knee function were significantly improved from baseline in all treated knees at one, three and six months after ADRCs. At six-months after ADRCs treatment, the second-look arthroscopy showed that almost all the cartilage defect areas were covered by regenerated cartilage, some cartilage fibrillation area was reduced, and meniscus tear areas were repaired. CONCLUSIONS: Cartilage and meniscus repair were observed six-months after ADRCs therapy under second-look arthroscopy. It was shown that a single administration of ADRCs might be effective as a treatment for knee osteoarthritis.

Rotational position of the tibial component can decrease bony coverage of the tibial component in Oxford mobile-bearing unicompartmental knee arthroplasty.

BACKGROUND: This study examined how coverage of the tibial component changes when the tibia vertical cut is externally or internally rotated in Oxford mobile-bearing unicompartmental knee arthroplasty. MATERIALS AND METHODS: Fifty patients scheduled for primary Oxford medial unicompartmental knee arthroplasty (UKA) at the current hospital were included in this study. This study was a computed tomography (CT) simulation study. The anteroposterior (AP) and mediolateral (ML) length as well as the ML/AP ratio of the tibial cut surfaces were calculated when the vertical cut was performed parallel (base line), five degrees externally rotated (ER5), 10° externally rotated (ER10), five degrees internally rotated (IR5), or 10° internally rotated (IR10) relative to the tibial AP line using pre-operative CT. The tibial AP line connecting the middle of the posterior collateral ligament to the medial border of the patellar tendon attachment is a reproducible and reliable line because it is perpendicular to the SEA. These parameters among three lines were compared using a repeated measures ANOVA. RESULTS: The mean ML/AP ratios were statistically significantly lower in ER5 (0.53 ±â€¯0.04) than base line (0.56 ±â€¯0.04) (P < 0.01). The ER10 (0.48 ±â€¯0.03) also exhibited lower mean ML/AP ratios than ER5 (0.53 ±â€¯0.04) (P < 0.01). The mean ML/AP ratios were higher in IR5 (0.59 ±â€¯0.04) than base line (0.56 ±â€¯0.04) (P < 0.01). The IR10 (0.63 ±â€¯0.06) also showed a higher mean ML/AP ratio than IR5 (0.59 ±â€¯0.04) (P < 0.01). CONCLUSION: Rotational malalignment of tibial vertical cuts can affect tibial coverage in Oxford mobile-bearing unicompartmental knee arthroplasty.

Influence of tibial component rotation on short-term clinical outcomes in Oxford mobile-bearing unicompartmental knee arthroplasty.

BACKGROUND: Malposition of tibial components is an important factor for complications in unicompartmental knee arthroplasty (UKA), but the direct relationship between clinical outcomes and position of tibial component remains unknown. We aimed to investigate whether tibial component rotation in the axial plane could affect clinical outcomes after UKA. METHODS: A total of 50 patients with anteromedial osteoarthritis of the knee underwent Oxford mobile-bearing UKA in this study. Patient-derived clinical scores using the Oxford Knee Score (OKS) and the functional activities of Knee Society Score (KSSF) were assessed preoperatively, and then after one year and two years following surgery. Postoperative tibial component rotation angles using two reference lines in the axial plane were assessed using three-dimensional computed tomography two weeks postoperatively. External rotation of the tibial component relative to each reference line was considered a positive value. We analysed the sequential change of the OKS and KSSF using repeated measures analysis of variance (P < 0.05). The effects of tibial component rotation on the OKS and KSSF were analysed using linear regression analysis. RESULTS: OKS and KSSF showed significant recovery between the preoperative and one-year postoperative period. Rotation angles of tibial components had significant negative correlations with the recovery of the OKS in the two years following UKA. CONCLUSIONS: Tibial component rotation played an important role in improving clinical outcomes during the two years following Oxford mobile-bearing UKA. A trend towards poor outcome was observed when the tibial component was placed at a higher angle of external rotation. LEVEL OF EVIDENCE: III.

Effect of tibial component position on short-term clinical outcome in Oxford mobile bearing unicompartmental knee arthroplasty.

BACKGROUND: Malposition of the tibial components is a well-known complication of unicompartmental knee arthroplasty. In this study, we aimed to ascertain the relationship between the tibial component position and clinical outcomes of unicompartmental knee arthroplasty. We focused on the tibial component height and obliquity in the coronal plane. METHODS: Patients with anteromedial osteoarthritis who underwent Oxford mobile-bearing unicompartmental knee arthroplasty (n = 45) were included, and their Oxford knee score was assessed prior to and 1 and 2 years following surgery. We also assessed the postoperative tibial component position in the coronal plane using radiography, measuring the tibial component height and obliquity. We analyzed the sequential change in both clinical scores using repeated measures analysis of variance (p < 0.05). The effects of tibial component position on the clinical outcomes were analyzed using linear regression analysis (p < 0.05). RESULTS: The Oxford knee score significantly improved 1 year after surgery. The tibial component height and obliquity had a significantly negative correlation with the 2-year postoperative Oxford knee score. They were also correlated significantly with Oxford knee score recovery after unicompartmental knee arthroplasty. CONCLUSION: The 2-year postoperative outcomes of Oxford unicompartmental knee arthroplasty depended on the tibial component position. We observed poorer outcomes when the tibial component was placed at a lower level relative to the lateral compartment and when there was an excessive valgus angle relative to the lower limb axis.

Unicompartmental knee arthroplasty for spontaneous osteonecrosis of the medial tibial plateau.

BACKGROUND: There have been very few reports on isolated medial tibial plateau osteonecrosis, and the condition has not been clearly described. Unicompartmental knee arthroplasty (UKA) may be an appropriate treatment method for this condition. The aims of this study were to report our experience of using mobile-bearing knee implants for osteonecrosis of the medial tibial plateau and to discuss the etiology and treatment of this type of osteonecrosis. METHODS: This study included six consecutive patients with isolated medial tibial plateau osteonecrosis treated with an Oxford mobile-bearing knee implant. The average age was 71.0 years. We preoperatively graded the tibial necrosis lesion using radiographic findings. We also assessed the area and size of necrosis, extent of the surrounding high-density area, and the presence of any meniscal lesions by preoperative magnetic resonance imaging (MRI), and pre- and postoperative Oxford Knee Scores (OKS) were evaluated. RESULTS: MRI findings revealed that all patients had meniscal lesions in addition to a necrotic lesion. All patients significantly improved in their OKS. No knees required revision for either infection or loosening. CONCLUSIONS: The etiology of these cases of necrosis is still unclear, but the current study suggested an association with medial meniscal lesions. The results of the study were promising, showing a good short-term clinical outcome of Oxford mobile-bearing UKA for this type of osteonecrosis.

Additional Visualization via Smart Glasses Improves Accuracy of Wire Insertion in Fracture Surgery.

BACKGROUND: Smart glasses (SG) are a wearable device consisting of a small computer built into a head-mounted monitor (HMM) that can display various kinds of information. Lateral side visualization is displayed on the HMM of SG so the operator may also see it and the anteroposterior (AP) direction simultaneously. The present pilot study aimed to investigate the usefulness of SG in wire insertion for bone fracture. METHODS: We marked both the front and lateral sides of the shaft of an artificial femur bone. From the tip of the greater trochanter, we inserted a 2.4-mm Kirschner wire (K-wire) so that it could be directed toward the marks in both planes. Three surgeons enrolled in the study each performed 10 trials, both with SG (SG arm) and without (direct vision arm). We defined the error angle as the angle between the K-wire and the line connecting the marking point from the insertion point in both the front and lateral view images. We also measured the time it took to insert the K-wire in both arms. RESULTS: The SG had a significantly reduced (mean = 3.2°) error angle ( P = .02) when compared to the direct vision group (mean = 4.8°). However, no significant difference was found between direct vision (mean = 17.5 seconds) and SG arms (mean = 14.9 seconds) in the insertion time. CONCLUSION: While keeping the AP image view in primary focus, simultaneously viewing the lateral side of the surgical field using SG helps achieve more accurate wire insertion in surgery.

Osteoarthritis with permanent dislocation of the patella treated by total knee arthroplasty through a lateral approach: A report of two cases.

INTRODUCTION: Permanent dislocation of the patella (PDP) is a rare condition. In cases of PDP with tibiofemoral arthritis, total knee arthroplasty may be performed through a medial parapatellar approach with patellar realignment. In this article we present two cases of PDP with tibiofemoral osteoarthritis successfully treated via lateral approach TKA without any additional realignment procedure. We performed two total knee arthroplasties for PDP with lateral tibiofemoral arthritis through a lateral approach without any realignment procedure. Mobile bearing inserts were used to adjust rotational alignment. The patients showed improved functional outcomes (Japanese Orthopaedic Association Knee score and Oxford Knee Score), and improved range of motion. Three years postoperatively, the patellae remain stable without dislocation nor maltracking, maintaining a high functional score. CONCLUSION: To treat permanent dislocation of the patella with lateral knee osteoarthritis, TKA through a lateral approach have potential to be a new treatment option to achieve both a good outcome and repositioning of the patella.

The Use of Smart Glasses for Surgical Video Streaming.

Observation of surgical procedures performed by experts is extremely important for acquisition and improvement of surgical skills. Smart glasses are small computers, which comprise a head-mounted monitor and video camera, and can be connected to the internet. They can be used for remote observation of surgeries by video streaming. Although Google Glass is the most commonly used smart glasses for medical purposes, it is still unavailable commercially and has some limitations. This article reports the use of a different type of smart glasses, InfoLinker, for surgical video streaming. InfoLinker has been commercially available in Japan for industrial purposes for more than 2 years. It is connected to a video server via wireless internet directly, and streaming video can be seen anywhere an internet connection is available. We have attempted live video streaming of knee arthroplasty operations that were viewed at several different locations, including foreign countries, on a common web browser. Although the quality of video images depended on the resolution and dynamic range of the video camera, speed of internet connection, and the wearer's attention to minimize image shaking, video streaming could be easily performed throughout the procedure. The wearer could confirm the quality of the video as the video was being shot by the head-mounted display. The time and cost for observation of surgical procedures can be reduced by InfoLinker, and further improvement of hardware as well as the wearer's video shooting technique is expected. We believe that this can be used in other medical settings.

Augmented reality: The use of the PicoLinker smart glasses improves wire insertion under fluoroscopy.

AIM: To demonstrate the feasibility of the wearable smart glasses, PicoLinker, in guide wire insertion under fluoroscopic guidance. METHODS: Under a fluoroscope, a surgeon inserted 3 mm guide wires into plastic femurs from the lateral cortex to the femoral head center while the surgeon did or did not wear PicoLinker, which are wearable smart glasses where the fluoroscopic video was displayed (10 guide wires each). RESULTS: The tip apex distance, radiation exposure time and total insertion time were significantly shorter while wearing the PicoLinker smart glasses. CONCLUSION: This study indicated that the PicoLinker smart glasses can improve accuracy, reduce radiation exposure time, and reduce total insertion time. This is due to the fact that the PicoLinker smart glasses enable surgeons to keep their eyes on the operation field.