Factors Causing Unintended Sagittal and Axial Alignment Changes in High Tibial Osteotomy: Comparative 3-Dimensional Analysis of Simulation and Actual Surgery.

BACKGROUND: Unintended secondary changes in the posterior tibial slope (PTS) and tibial torsion angle (TTA) may occur after medial open-wedge high tibial osteotomy (MOWHTO). In surgical procedures using patient-specific instruments (PSIs), it is essential to reproduce the PTS and TTA that were planned in simulations. PURPOSE: To analyze the factors causing unintended sagittal and axial alignment changes after MOWHTO. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Overall, 63 patients (70 knees) who underwent MOWHTO using a PSI between June 2020 and June 2023 were retrospectively reviewed. Preoperative and postoperative computed tomography scans were 3-dimensionally reconstructed. Simulated osteotomy was performed so that the weightbearing line could pass through the target point. A PSI gapper was 3-dimensionally printed to fit the posteromedial corner of the osteotomy gap in the simulated HTO model. After MOWHTO using the PSI gapper, the actual postoperative model was compared with the preoperative or simulation model. This assessment included PTS, TTA, hinge axis, and osteotomy-related parameters. Cortical breakage around the lateral hinge was evaluated to assess stability. RESULTS: The mean PTS and TTA did not change in the simulation. However, significant changes were observed in the actual postoperative PTS and TTA (change, -2.4°± 2.2° and -3.9°± 4.7°, respectively). The PTS was reduced, while the TTA decreased with internal rotation of the distal fragment. The difference in the axial hinge axis angle (AHA) between the simulation and actual surgery was the factor most correlated with the difference in the PTS (r = 0.625; P < .001). In regression analysis, the difference in the AHA was the only factor associated with the difference in the PTS (ß = 0.558; P = .001), and there were no factors that showed any significant associations with the difference in the TTA. In subgroup analyses for the change in the TTA, the correction angle and anterior osteotomy angle were significantly higher in the more internal rotation group (P = .023 and P = .010, respectively). The TTA change was significantly higher in the unstable group with lateral cortical breakage (P = .018). The unstable group was more likely to show an internal rotation of ≥5° (odds ratio, 5.0; P = .007). CONCLUSION: The AHA was associated with a difference in the PTS between the simulation and actual surgery. The change in the TTA was caused by a combination of multiple factors, such as a large correction angle and anterior osteotomy angle, but mainly by instability of the lateral cortical hinge.

Effects of concurrent cartilage procedures on cartilage regeneration in high tibial osteotomy: a systematic review.

PURPOSE: This systematic review aimed to evaluate the effects of concurrent cartilage procedures on cartilage regeneration when performed alongside high tibial osteotomy (HTO). MATERIALS AND METHODS: The systematic review followed the guidelines outlined in the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A comprehensive search was conducted on databases including PubMed, Embase, Cochrane Library, and Google Scholar, covering articles published until August 31, 2023. RESULTS: Sixteen studies (1277 patients) revealed that HTO, with or without concurrent cartilage procedures, leads to cartilage regeneration based on the International Cartilage Repair Society (ICRS) grade during second-look arthroscopy. No concurrent procedure showed improvement in ICRS grade (mean difference: - 0.80 to - 0.49). Microfracture (mean difference: - 0.75 to - 0.22), bone marrow aspirate concentrate (BMAC) (mean difference: - 1.37 to - 0.67), and human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) (mean difference: - 2.46 to - 1.81) procedures also demonstrated positive outcomes. Clinical outcome assessments for each cartilage procedure were also improved during postoperative follow-up, and no specific complications were reported. CONCLUSIONS: HTO with or without concurrent cartilage procedures promotes cartilage regeneration observed during second-look arthroscopy, with improved clinical outcomes. Future randomized controlled trials on the same topic, along with subsequent meta-analyses, are necessary for conclusive findings.

Implantation of hUCB-MSCs generates greater hyaline-type cartilage than microdrilling combined with high tibial osteotomy.

PURPOSE: To compare the outcomes of treating large cartilage defects in knee osteoarthritis using human allogeneic umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation or arthroscopic microdrilling as a supplementary cartilage regenerative procedure combined with high tibial osteotomy (HTO). METHODS: This 1-year prospective comparative study included 25 patients with large, near full-thickness cartilage defects (International Cartilage Repair Society grade ≥ IIIB) in the medial femoral condyles and varus malalignment. Defects were treated with hUCB-MSC implantation or arthroscopic microdrilling combined with HTO. The primary outcomes were pain visual analogue scale and International Knee Documentation Committee subjective scores at 12, 24 and 48 weeks. Secondary outcomes included arthroscopic, histological and magnetic resonance imaging assessments at 1 year. RESULTS: Fifteen and 10 patients were treated via hUCB-MSC implantation and microdrilling, respectively. Baseline demographics, limb alignment and clinical outcomes did not significantly differ between the groups. Cartilage defects and total restored areas were significantly larger in the hUCB-MSC group (7.2 ± 1.9 vs. 5.2 ± 2.1 cm2, p = 0.023; 4.5 ± 1.4 vs. 3.0 ± 1.6 cm2, p = 0.035). The proportion of moderate-to-strong positive type II collagen staining was significantly higher in the hUCB-MSC group compared to that in the microdrilled group (93.3% vs. 60%, respectively). Rigidity upon probing resembled that of normal cartilage tissue more in the hUCB-MSC group (86.7% vs. 50.0%, p = 0.075). Histological findings revealed a higher proportion of hyaline cartilage in the group with implanted hUCB-MSC (p = 0.041). CONCLUSION: hUCB-MSC implantation showed comparable clinical outcomes to those of microdrilling as supplementary cartilage procedures combined with HTO in the short term, despite the significantly larger cartilage defect in the hUCB-MSC group. The repaired cartilage after hUCB-MSC implantation showed greater hyaline-type cartilage with rigidity than that after microdrilling. LEVEL OF EVIDENCE: Level II, Prospective Comparative Cohort Study.

Allogeneic umbilical cord blood-derived mesenchymal stem cell implantation versus microdrilling combined with high tibial osteotomy for cartilage regeneration.

This study compared cartilage regeneration outcomes in knee osteoarthritis (OA) using allogeneic human umbilical cord blood-derived mesenchymal stem cell (hUCB-MSC) implantation and microdrilling with high tibial osteotomy (HTO). Fifty-four patients (60 knees) were included: 24 (27 knees) in the hUCB-MSC group and 30 (33 knees) in the microdrilling group. Both groups showed significant improvements in pain and functional scores at 6, 12, and 24 months compared to baseline. At 24 months, the hUCB-MSC group had significantly improved scores. Arthroscopic assessment at 12 months revealed better cartilage healing in the hUCB-MSC group. In subgroup analysis according to the defect site, hUCB-MSC implantation showed superior cartilage healing for anterior lesions. In conclusion, both treatments demonstrated effectiveness for medial OA. However, hUCB-MSC implantation had better patient-reported outcomes and cartilage regeneration than microdrilling. The study suggests promising approaches for cartilage restoration in large knee defects due to OA.

Prognostic Factors for Clinical Outcome and Cartilage Regeneration after Implantation of Allogeneic Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells in Large-Sized Cartilage Defects with Osteoarthritis.

OBJECTIVE: To analyze the prognostic factors for clinical outcomes and cartilage regeneration after the implantation of allogeneic human umbilical cord blood mesenchymal stem cell (hUCB-MSC) for treating large-sized cartilage defects with osteoarthritis. DESIGN: This study is a case-series with multiple subgroup analyses that divides the included patients into multiple subgroups based on various factors. Overall, 47 patients who underwent hUCB-MSC implantation were included. The patient-reported outcomes, magnetic resonance imaging (MRI), and second-look arthroscopy were used to assess the outcomes. RESULTS: Combined realignment surgery significantly correlated with clinical outcomes, particularly pain. No other factors significantly influenced the clinical outcomes in short-term period. Subgroups with large defect sizes or meniscal insufficiency showed significantly poor MRI and arthroscopy outcomes (MRI, P = 0.001, P = 0.001; arthroscopy, P = 0.032, P = 0.042). The logistic regression showed that patients with a 1 cm2 larger defect size were 1.91 times less likely to achieve favorable MRI outcomes (P = 0.017; odds ratio [OR], 1.91). Cut-off value to predict the poor outcome was >5.7 cm2 (area under the curve, 0.756). A cartilage defect size >5.7 cm2 was the major poor prognostic factor for cartilage regeneration on MRI (P = 0.010; OR, 17.46). If the postoperative alignment shifted by 1° opposite to the cartilage defect, it was 1.4 times more likely to achieve favorable MRI outcomes (P = 0.028; OR, 1.4). CONCLUSION: Combining realignment surgery showed a better prognosis for pain improvement. Cartilage defect size, meniscal function, and postoperative alignment are significant prognostic factors for cartilage regeneration. A cartilage defect size >5.7 cm2 was significantly related to poor cartilage regeneration.

Preoperative joint line obliquity, a newly identified factor for overcorrection, can be incorporated into a novel preoperative planning method to optimise alignment in high tibial osteotomy.

PURPOSE: The aim of this study was to analyse the factors associated with additional postoperative alignment changes after accurate bony correction by selecting only patients with well-performed bony correction as planned and develop a method of incorporating significant factors into preoperative planning. METHODS: Among 104 consecutive patients who underwent medial open wedge high tibial osteotomy (MOWHTO) between October 2019 and July 2022, 61 with well-performed bony corrections were retrospectively reviewed. The major criterion for well-performed bony correction was a difference of <1° between the simulated medial proximal tibial angle (MPTA) and the actual postoperative MPTA as measured in three dimensions. Radiographic parameters, such as the joint line convergence angle (JLCA) and joint line obliquity (JLO), were measured preoperatively and postoperatively, utilising standing and supine whole lower extremity anteroposterior, valgus and varus stress radiographs. Multiple linear regression analysis identified the factors affecting alignment changes, and a prediction model was developed. A method for applying this prediction model to preoperative planning was proposed. RESULTS: Preoperative JLCA on standing (preJLCAstd ), preoperative JLCA on 0° valgus stress radiograph (vgJLCA0 ), and preoperative JLO (preJLO) were significantly correlated with JLCA change (∆JLCA) (p < 0.001, p < 0.001, p = 0.006). The prediction model was estimated as ∆JLCA = 0.493 × (vgJLCA0 ) - 0.727 × (preJLCAstd ) + 0.189 × (preJLO) - 1.587 in. (R = 0.815, modified R2 = 0.646, p < 0.001). The proposed method resulted in a reduced overcorrection rate (p = 0.003) and an improved proportion of acceptable alignments (p = 0.013). CONCLUSION: PreJLCAstd , vgJLCA0  and preJLO can be used to estimate ∆JLCA. PreJLO was recently identified as a significant factor associated with additional alignment changes. Utilising the proposed preoperative planning and a prediction model with these factors shows promise in calibrating postoperative alignment after MOWHTO. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Release or transection of superficial medial collateral ligament during open-wedge high tibial osteotomy demonstrated similar clinical outcomes and valgus laxity.

PURPOSE: To analyse whether valgus laxity and clinical outcomes differ depending on whether the superficial medial collateral ligament (sMCL) is released or transected during medial open-wedge high tibial osteotomy (MOWHTO). METHODS: Consecutive patients who underwent MOWHTO and subsequent radiological follow-up for at least 2 years were retrospectively evaluated. The patients were divided into release and transection groups, according to the sMCL manipulation technique. Each patient was assessed for the following variables on valgus stress radiographs taken before surgery and at the 12- and 24-month follow-ups: the absolute value of valgus (ABV) and side-to-side difference (SSD) between the affected and normal sides. The differences between preoperative SSD and those at 12 and 24 months were respectively calculated and defined as delta SSD (ΔSSD). The Visual Analogue Scale, Lysholm knee, International Knee Documentation Committee subjective, and Knee Injury and Osteoarthritis Outcome scores were used to evaluate patient-reported outcomes. RESULTS: Eighty-five patients were included in the study. Forty-two patients (49.6%) underwent sMCL release, and the remaining 43 patients (50.4%) underwent sMCL transection. No significant differences were observed in the ABV and SSD of valgus laxity at the different time points between the two groups (n.s.). Furthermore, no significant differences were observed in the ΔSSD at the 12- and 24-month follow-ups between the two groups (n.s.). Significant improvement from preoperative values was observed in all patient-reported outcomes (p < 0.001), with no significant differences between the two groups at any time point (n.s.). CONCLUSION: Significant improvements in clinical outcomes were observed, regardless of the technique used. Postoperative valgus laxity did not occur with either technique. The transection technique, which can be performed more simply and quickly, demonstrated similar clinical outcomes and valgus laxity to the release technique. LEVEL OF EVIDENCE: Level III.

Decellularized allogeneic cartilage paste with human costal cartilage and crosslinked hyaluronic acid-carboxymethyl cellulose carrier augments microfracture for improved articular cartilage repair.

Articular cartilage lacks natural healing abilities and necessitates surgical treatments for injuries. While microfracture (MF) is a primary surgical approach, it often results in the formation of unstable fibrocartilage. Delivering hyaline cartilage directly to defects poses challenges due to the limited availability of autologous cartilage and difficulties associated with allogeneic cartilage delivery. We developed a decellularized allogeneic cartilage paste (DACP) using human costal cartilage mixed with a crosslinked hyaluronic acid (HA)-carboxymethyl cellulose (CMC) carrier. The decellularized allogeneic cartilage preserved the extracellular matrix and the nanostructure of native hyaline cartilage. The crosslinked HA-CMC carrier provided shape retention and moldability. In vitro studies confirmed that DACP did not cause cytotoxicity and promoted migration, proliferation, and chondrogenic differentiation of human bone marrow-derived mesenchymal stem cells. After 6 months of implantation in rabbit knee osteochondral defects, DACP combined with MF outperformed MF alone, demonstrating improved gait performance, defect filling, morphology, extracellular matrix deposition, and biomechanical properties similar to native cartilage. Thus, DACP offers a safe and effective method for articular cartilage repair, representing a promising augmentation to MF. STATEMENT OF SIGNIFICANCE: Directly delivering hyaline cartilage to repair articular cartilage defects is an ideal treatment. However, current allogeneic cartilage products face delivery challenges. In this study, we developed a decellularized allogeneic cartilage paste (DACP) by mixing human costal cartilage with crosslinked hyaluronic acid (HA)-carboxymethyl cellulose (CMC). DACP preserves extracellular matrix components and nanostructures similar to native cartilage, with HA-CMC ensuring shape retention and moldability. Our study demonstrates improved cartilage repair by combining DACP with microfracture, compared to microfracture alone, in rabbit knee defects over 6 months. This is the first report showing better articular cartilage repair using decellularized allogeneic cartilage with microfracture, without the need for exogenous cells or bioactive substances.

Influence of knee flexion angle on graft bending angle during anterior cruciate ligament reconstruction using the transportal technique.

This study aimed to examine change in the graft bending angle (GBA) according to various knee flexion angles in creating femoral tunnel by the transportal technique in ACL reconstruction, and to reveal knee flexion angle minimizing GBA while maintaining stable femoral tunnel characteristics. Patients who underwent ACL reconstruction using the transportal technique between January 2017 and December 2018 were retrospectively reviewed. Patients were classified into three groups according to knee flexion angle when creating femoral tunnel (group 1: < 120° (n = 19); group 2: 120-129° (n = 32); group 3: ≥ 130° (n = 33). GBA was measured on three-dimensional knee model reconstructed from postoperative computed tomography images. The length of the femoral tunnel and posterior wall blow-out were also checked. There was significant difference of GBA between the groups (group 1 = 112.1°; group 2 = 106.4°; group 3 = 101.4°, p < 0.001). The knee flexion angle in creating femoral tunnel was negatively correlated with GBA (r = - 0.733, p < 0.001). Five patients in group 1 had short femoral tunnel. GBA was influenced by knee flexion angle in creating femoral tunnel and got more acute as the knee flexion angle increased. Considering length and risk of wall blow-out in femoral tunnel, and GBA, knee flexion angle between 120 and 130° could be recommended as appropriate angle to create optimal femoral tunnel in ACL reconstruction using the transportal technique.

Particulated Costal Allocartilage With Microfracture Versus Microfracture Alone for Knee Cartilage Defects: A Multicenter, Prospective, Randomized, Participant- and Rater-Blinded Study.

Background: Microfracture is the first-line treatment for cartilage defects; however, the suboptimal quality of the repaired cartilage remains an issue. Purpose/Hypothesis: The aim of this first in-human study was to compare the clinical efficacy and safety of a combination of particulated costal allocartilage and microfracture versus microfracture alone in treating knee cartilage defects. We hypothesized that the particulated costal allocartilage with microfracture would result in superior cartilage repair quality and better clinical outcomes at 48 weeks postoperatively. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Patients with cartilage defects were allocated randomly to the treatment group (particulated costal allocartilage with microfracture) and control group (microfracture alone). Magnetic resonance imaging (MRI) outcomes of cartilage repair (the primary outcome measure) were evaluated at the 48-week follow-up using the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. Patient-reported clinical outcomes (visual analog scale [VAS] pain score, Knee injury and Osteoarthritis Outcome Score [KOOS], and International Knee Documentation Committee score) and adverse events were evaluated at 12, 24, and 48 weeks postoperatively. Results: Overall, 88 patients were included (44 patients each in the treatment and control groups). The total MOCART score at 48 weeks postoperatively was significantly higher in the treatment group than in the control group (P < .001). Among the 9 MOCART variables, 6 were significantly superior in the treatment versus the control group: degree of repair and defect filling (P < .001), integration to the border zone (P < .001), surface (P = .006), structure (P = .011), signal intensity of the repair tissue (P < .001), and subchondral lamina (P = .005). There were significant between-group differences in KOOS-Pain (P = .014), KOOS-Activities of Daily Living (P = .010), KOOS-Sports (P = .029), and KOOS-Symptoms (P = .039) at 12 weeks postoperatively and in VAS pain (P = .012) and KOOS-Pain (P = .005) at 24 weeks postoperatively. At 48 weeks postoperatively, clinical outcomes were comparable between the groups. Conclusion: Microfracture augmented with particulated costal allocartilage resulted in superior cartilage repair quality compared with microfracture alone in terms of MRI evaluation of the knee joint cartilage defect at the 48-week follow-up. Functional outcomes were favorable for both treatments at final follow-up. Registration: KCT0004936 (Clinical Research Information Service [CRiS] of the Republic of Korea).

Medial Meniscus Posterior Root Tear: How Far Have We Come and What Remains?

Medial meniscus posterior root tears (MMRTs), defined as tears or avulsions that occur within 1 cm of the tibial attachment of the medial meniscus posterior root, lead to biomechanically detrimental knee conditions by creating a functionally meniscal-deficient status. Given their biomechanical significance, MMRTs have recently been gaining increasing interest. Accordingly, numerous studies have been conducted on the anatomy, biomechanics, clinical features, diagnosis, and treatment of MMRTs, and extensive knowledge has been accumulated. Although a consensus has not yet been reached on several issues, such as surgical indications, surgical techniques, and rehabilitation protocols, this article aimed to comprehensively review the current knowledge on MMRTs and to introduce the author's treatment strategies.

Factors Influencing the Initial Constraint Level of the Knee Joint and Its Effect on Clinical Outcomes After ACL Reconstruction With Hamstring Graft.

Background: A force-based tension protocol that uses a certain amount of tension at graft fixation could still give rise to variations in initial constraint levels of the knee joint in terms of side-to-side difference (SSD) in anterior translation. Purpose: To investigate the factors influencing the initial constraint level in anterior cruciate ligament (ACL)-reconstructed knees and compare outcomes according to the level of constraint in terms of anterior translation SSD. Study Design: Cohort study; Level of evidence, 3. Methods: Included were 113 patients who underwent ipsilateral ACL reconstruction using an autologous hamstring graft and had minimum 2-year follow-up outcomes. All grafts were tensioned and fixed at 80 N using a tensioner at the time of graft fixation. The patients were classified into the following 2 groups according to the initial anterior translation SSD, measured using the KT-2000 arthrometer: a physiologic constraint group with restored anterior laxity ≤2 mm (group P; n = 66) and a high-constraint group with restored anterior laxity >2 mm (group H; n = 47). Clinical outcomes were compared between the groups, and preoperative and intraoperative variables were evaluated to identify factors affecting the initial constraint level. Results: Between group P and group H, generalized joint laxity (P = .005), posterior tibial slope (P = .022), and anterior translation measured in the contralateral knee (P < .001) were found to differ significantly. Measured anterior translation in the contralateral knee was the only significant predictor of high initial graft tension (P = .001). No significant differences were found between the groups regarding clinical outcomes and subsequent surgery. Conclusion: Greater anterior translation measured in the contralateral knee was an independent predictor of a more constrained knee after ACL reconstruction. The short-term clinical outcomes after ACL reconstruction were comparable, regardless of the initial constraint level in terms of anterior translation SSD.

The Relationship Between Lateral Femoral Anatomic Structures and the Femoral Tunnel Outlet in Anterior Cruciate Ligament Reconstruction Using the Transportal Technique: A 3-Dimensional Simulation Analysis.

BACKGROUND: The relationship between the lateral femoral anatomic structures and femoral tunnel outlet according to changes in knee flexion and transverse drill angle during femoral tunnel creation in anterior cruciate ligament (ACL) reconstruction remains unclear. PURPOSE: To investigate the relationships between the lateral femoral anatomic structures and femoral tunnel outlet according to various knee flexion and transverse drill angles and to determine appropriate angles at which to minimize possible damage to the lateral femoral anatomic structures. STUDY DESIGN: Controlled laboratory study. METHODS: Simulation of ACL reconstruction was conducted using a 3-dimensional reconstructed knee model from the knees of 30 patients. Femoral tunnels were created using combinations of 4 knee flexion and 3 transverse drill angles. Distances between the femoral tunnel outlet and lateral femoral anatomic structures (minimum safe distance, 12 mm), tunnel length, and tunnel wall breakage were assessed. RESULTS: Knee flexion and transverse drill angles independently affected distances between the femoral tunnel outlet and lateral femoral anatomic structures. As knee flexion angle increased, the distance to the lateral collateral ligament, lateral epicondyle, and popliteal tendon decreased, whereas the distance to the lateral head of the gastrocnemius increased (P < .001). As the transverse drill angle decreased, distances to all lateral femoral anatomic structures increased (P < .001). Considering safe distance, 120°, 130°, or 140° of knee flexion and maximum transverse drill angle (MTA) could damage the lateral collateral ligament; 130° or 140° of knee flexion and MTA could damage the lateral epicondyle; and 110° or 120° of knee flexion and MTA could damage the lateral head of the gastrocnemius. Tunnel wall breakage occurred under the conditions of MTA - 10° or MTA - 20° with 110° of knee flexion and MTA - 20° with 120° of knee flexion. CONCLUSION: Approximately 120° of knee flexion with MTA - 10° and 130° or 140° of knee flexion with MTA - 20° or MTA - 10° could be recommended to prevent damage to the lateral femoral anatomic structures, secure adequate tunnel length, and avoid tunnel wall breakage. CLINICAL RELEVANCE: Knee flexion angle and transverse drill angle may affect femoral tunnel creation, but thorough studies are lacking. Our findings may help surgeons obtain a stable femoral tunnel while preventing damage to the lateral femoral anatomic structures.

Vascular Calcification in Patients Undergoing Total Knee Arthroplasty: Frequency and Effects on the Surgery.

BACKGROUD: This study aims to investigate the frequency of distal femoral and popliteal arterial calcification and to evaluate the intraoperative and postoperative effects of arterial calcification in patients undergoing total knee arthroplasty using a tourniquet. METHODS: The records of 5,438 patients who had undergone primary total knee arthroplasty between January 2003 and January 2017 were retrospectively reviewed. We examined the preoperative radiographs of the knee from all patients for calcifications of the femoral and popliteal arteries. Vascular calcification was identified on preoperative radiographs in 223 cases. Intraoperative and postoperative complications were investigated among these patients. Postoperative complications were analyzed from the time of surgery to the last follow-up (minimum 1-year follow-up). RESULTS: Vascular calcification of the arteries around the knee was found in 223 cases (4.1%). The mean patient age was 70.6 years in the non-calcification group and 73.8 years in the calcification group (p > 0.05). The calcification group was classified into medial, intimal, or mixed subgroups according to the morphology of calcification on preoperative radiographs. The medial type included 46 cases (20.6%); intimal type, 161 cases (72.2%); and mixed type, 16 cases (2.7%). There was no statistically significant difference in demographic and surgical data among the three groups. There were intraoperative complications in two cases in the medial type group, both of which involved tourniquet failure. There was also a postoperative complication in one case in the medial type group, which involved wound dehiscence at 2 weeks postoperatively. No other postoperative complications were identified during 1-year follow-up. CONCLUSIONS: Despite the presence of calcifications in the arteries around the knee, total knee arthroplasty (using a tourniquet) can be performed without serious complications.

Association between platelet count and osteoarthritis in women older than 50 years.

BACKGROUND: Osteoarthritis (OA) is a multifactorial disease involving inflammatory processes. Platelets play important roles in both hemostasis and the inflammatory response; however, the relationship between platelet count and OA is unclear. Our aim was to evaluate the association between platelet count and knee and hip OA in Korean women. METHODS: In this cross-sectional designed study, we included a total of 6011 women aged ⩾50 years from the 2010-2013 Korea National Health and Nutrition Examination Survey. Knee and hip OA were defined as Kellgren-Lawrence grade ⩾2 and presence of knee or hip pain, respectively. Platelet counts were divided into quartiles as follows: Q1, 150-212 (103/µl); Q2, 213-246 (103/µl); Q3, 247-283 (103/µl); and Q4, 284-450 (103/µl). Multiple logistic-regression analysis was conducted to calculate odds ratios and 95% confidence intervals. Receiver operating characteristic analysis was performed to determine the optimal platelet count cut-off with which to discriminate participants with knee and/hip OA versus those without OA. RESULTS: Of the 6011 participants, 1141 (18.1%) had knee or hip OA. The mean age of participants without OA was 60.6 years, and that of participants with OA was 68.0 years. Compared with the lowest quartile, odds ratios (95% confidence intervals) for OA were 1.08 (0.84-1.39) for Q2, 0.94 (0.73-1.23) for Q3, and 1.35 (1.08-1.69) for Q4 after adjusting for confounders. The prevalence of OA was significantly higher with platelet counts ⩾288 × 103/µl, compared with platelet counts <288 × 103/µl. CONCLUSION: High platelet counts within the normal range are significantly associated with knee and hip OA.

What can the radiological parameters of superior migration of the humeral head tell us about the reparability of massive rotator cuff tears?

OBJECTIVE: The interrelation and clinical utility of the parameters for superior migration of the humeral head, such as the acromiohumeral interval (AHI), inferior glenohumeral distance (IGHD), and upward migration index (UMI), in the management of massive rotator cuff tears are not clear. The objectives of this study were to identify the relation between AHI, IGHD, and UMI when measured with radiography and MRI and to determine whether superior migration can predict the irreparability of massive rotator cuff tears. METHODS: We retrospectively reviewed the files of 64 consecutive patients who underwent arthroscopic partial or complete repair for massive rotator cuff tears at our institution between August 2015 and August 2018. We recorded both radiography and MRI measurements of AHI, IGHD, and UMI, and further the tangent sign, fatty infiltration of the rotator cuff muscles, and the Patte grade. We performed correlation assessments and multiple logistic regression analysis to identify potential predictors of the reparability of massive rotator cuff tears. RESULTS: Thirty-five patients had partially reparable and 29 had completely reparable tears. Parameters measured with either radiography or MRI were highly correlated with each other. The radiographic measurements showed a moderate or low correlation with the MRI measurements. All parameters of superior migration of the humeral head on radiography and MRI, the tangent sign, fatty infiltration of the infraspinatus muscle, and the Patte grade showed significant differences between patients with partially and completely repaired tears. Among these, the independent predictors for irreparability was Patte grade = 3. CONCLUSION: The AHI, IGHD, and UMI were highly correlated when measured with either radiography or MRI, but not when comparing their radiographic with their MRI values. Furthermore, they were not independent indicators of reparability in massive rotator cuff tears.

Osteochondral Fracture of Posterior Aspect of Lateral Femoral Condyle After Lateral Patella Dislocation: A Case Report.

CASE: A healthy 15-year-old girl presented with osteochondral fracture at the posterior aspect of the lateral femoral condyle (LFC) associated with a right patellar dislocation after a noncontact injury. The patient remained asymptomatic 18 months after the arthroscopically assisted reduction and internal fixation of the osteochondral fracture using bioabsorbable pins and was able to eventually resume her usual activities of daily living. CONCLUSIONS: This is the first report of an osteochondral fracture at the posterior aspect of the LFC after an acute patellar dislocation, successfully treated with arthroscopically assisted reduction and internal fixation using bioabsorbable pins. This rare injury and unique mechanism of injury have been discussed.

Does Knee Flexion Influence the Relationship between the Femoral Tunnel and the Lateral Anatomic Structures During ACL Reconstruction?

BACKGROUND: In ACL reconstruction, the relationship of the femoral tunnel outlet to the anatomy of the lateral knee is clinically important, but whether that relationship is influenced by knee flexion using a transportal technique is unclear. QUESTIONS/PURPOSES: The purposes of this study were to (1) to describe the relationship between the outlet of the femoral tunnel and the lateral anatomic structures of the femur, including the lateral epicondyle, lateral collateral ligament, popliteus tendon, and lateral head of the gastrocnemius, as a function of knee flexion angle when the tunnel was created; and (2) to determine the knee flexion range of angles that best limits the risk of damage to these structures as the femoral tunnel is created during anatomic single-bundle ACL reconstruction using the transportal technique. METHODS: Between January 2017 and June 2018, 113 patients underwent ACL reconstruction, of which 62 (55%) who had a primary single-bundle ACL reconstruction with transportal technique using autogenous quadruple hamstring graft were included. Patients who were treated with grafts other than autogenous quadruple hamstring tendon, and had concomitant ligamentous injury, revisional ACL reconstruction, previous operative history of the affected knee, osseous deformity and osteoarthritis were excluded. Included patients were divided into three groups according to their knee flexion angles as the femoral tunnel was created. The femoral tunnel was created with rigid straight reamer with the knee flexed as much as possible in figure-of-four position and the flexion angle was measured with a sterile 12-inch goniometer intraoperatively for all patients. Fourteen patients (23%) had the femoral tunnel created with the knee in < 120° of flexion, 23 (37%) had the tunnel created in 120° to 129° of flexion, and 25 (40%) had the tunnel created in ≥ 130° of flexion. The femoral tunnel's outlet and the lateral anatomic structures of the femur, including the femoral origins of the lateral epicondyle, lateral collateral ligament, popliteus tendon, and lateral head of the gastrocnemius, were identified on a three-dimensional model that was reconstructed using CT images taken on postoperative day 1. The shortest distances from the femoral tunnel's outlet to these lateral anatomic structures were measured by two observers and interobserver reliability was high (intraclass correlation coefficient > 0.75). The distances were compared among the groups, and a correlation analysis of the measured distances regarding the knee flexion angle during creation of the femoral tunnel was performed. The safe distance was set as 12 mm between the centers of the femoral tunnel's outlet and the lateral structures considering the footprint of the lateral structures, diameter of the femoral tunnel, and femoral tunnel widening. Any anatomic structures that were closer to the femoral tunnel than the safe distance were noted, and the cutoff point of knee flexion for injury to the lateral anatomic structures was determined with a receiver operating characteristic curve. RESULTS: As knee flexion angle increased, the distance from the femoral tunnel to the lateral head of the gastrocnemius increased (r = 0.657, p < 0.001), and the distance to the lateral epicondyle decreased (r = -0.627, p < 0.001), as did the distance of the tunnel to the lateral collateral ligament (r = -0.443, p < 0.001) and the popliteus tendon (r = -0.653, p < 0.001). The cutoff point of the knee flexion angle associated with structural injury was 131° (sensitivity, 70%; specificity, 73%) for the lateral collateral ligament and 121° (sensitivity, 86%; specificity, 67%) for the lateral head of the gastrocnemius. CONCLUSIONS: As knee flexion increased, the femoral tunnel's outlet tended to move more anteriorly and distally. Consequently, the safe distance to the lateral head of the gastrocnemius increased and the distances to the lateral epicondyle, lateral collateral ligament, and popliteus tendon decreased with increased knee flexion. To avoid possible damage to the lateral anatomic structures and obtain stable fixation in ACL reconstruction using the transportal technique, we recommend creating a femoral tunnel within 121° and 131° of knee flexion. LEVEL OF EVIDENCE: Level III, therapeutic study.

Ulnar nerve stability-based surgery for cubital tunnel syndrome via a small incision: a comparison with classic anterior nerve transposition.

OBJECTIVE: The purpose of this study was to compare the clinical outcomes of ulnar nerve stability-based surgery via a small incision with those of classic anterior transposition of the ulnar nerve for cubital tunnel syndrome. METHODS: From March 2008 to December 2013, 107 patients with cubital tunnel syndrome underwent simple decompression or anterior transposition via a small incision, according to an ulnar nerve stability-based decision based on an assessment of intraoperative ulnar nerve stability (group A, n = 51), or anterior transposition via a classic incision (group B, n = 56). Clinical outcome was assessed using grip and pinch strength, two-point discrimination, the mean of the disabilities of arm, shoulder, and hand (DASH) survey, and the modified Bishop scale. RESULTS: At the final follow-up, all outcome measures improved significantly in both groups and there were no significant differences between the two groups. However, there were fewer operation-related complications in group A (one revision surgery) than in group B (one superficial infection, two painful scars, and five cases of numbness at the medial elbow). CONCLUSIONS: Outcomes after the ulnar nerve stability-based approach and anterior transposition were similar, although more patients experienced operation-related complications after anterior transposition via a classic incision. Making an ulnar nerve stability-based decision to perform either simple decompression or anterior transposition via a small incision seems to be a better strategy for patients with cubital tunnel syndrome.