High-molecular-weight Hyaluronan Administration Inhibits Bone Resorption and Promotes Bone Formation in Young-age Osteoporosis Rats.

Osteoporosis poses a significant global health concern, affecting both the elderly and young individuals, including athletes. Despite the development of numerous antiosteoporotic drugs, addressing the unique needs of young osteoporosis patients remains challenging. This study focuses on young rats subjected to ovariectomy (OVX) to explore the impact of high-molecular-weight hyaluronan (HA) on preventing OVX-induced osteoporosis. Twenty-four rats underwent OVX, while 12 underwent sham procedures (sham control group). Among the OVX rats, half received subcutaneous injections of HA (MW: 2700 kDa) at 10 mg/kg/week into their backs (OVX-HA group), whereas the other half received saline injections (0.5 ml/week) at the same site (OVX-saline group). OVX-HA group exhibited significantly higher percentages of osteoclast surface (Oc. S/BS), osteoblast surface per bone surface (Ob. S/BS), and bone volume/tissue volume (BV/TV) compared with OVX-saline group at the same age. The proportions of Ob. S/BS and BV/TV in the OVX-HA group closely resembled those of the sham control group, whereas the proportion of Oc. S/BS in the OVX-HA group was notably higher than that in the sham control group. In summary, the administration of HA significantly mitigated bone resorption and enhanced bone formation, suggesting a crucial role for HA in the treatment of young adult osteoporosis.

Simple parameters to identify patients treatable with early definitive fixation: A nationwide study.

INTRODUCTION: Early appropriate care (EAC) is widely accepted as a safe strategy to perform early definitive fracture fixation, and good clinical outcomes have been reported in selected, multiply injured patients, although the optimal candidate for early definitive fixation (EDF) has not been validated. The aim of this study was to identify simple clinical parameters to help select patients who could undergo EDF. METHODS: Patients with extremity injuries who underwent open reduction and internal fixation were retrospectively identified, using data from the Japan Trauma Data Bank (JTDB). Age, vital signs on hospital presentation, and the injury severity score (ISS) were examined by transforming these variables to binary categories. Patients were divided into categories based on these variables, and in-hospital mortality was compared between patients treated with EDF (EDF group) and those treated without EDF (non-EDF group) in each category. RESULTS: Of the 12,735 patients who were eligible for the analyses, 3706 (29.1 %) were managed with EDF. In-hospital mortality was significantly higher in the EDF group than in the non-EDF group among patients with a low Glasgow Coma Scale (GCS) score (<13), low systolic blood pressure (sBP) (<90 mmHg), and ISS≥15, whereas in-hospital mortality was comparable between the EDF and non-EDF groups among patients with GCS scores ≥13, sBP ≥90 mmHg, and ISS <15. DISCUSSION: In this large nationwide database of trauma patients, EDF was performed without affecting mortality in patients with GCS scores ≥13 and sBP ≥90 mmHg on hospital presentation, as well as ISS <15. These parameters might be useful as screening tools to select the candidates who could be treated with EDF safely.

Clinical parameters and optimal candidates for early definitive fixation of extremity injury: A nationwide study.

BACKGROUND: While various strategies of fracture fixation for trauma patients have been discussed, optimal candidates remain unclear for early definitive fixation. The aim of this study was to integrate several clinical parameters into a scoring system and determine a cut-off value for safe early definitive surgery for extremity fractures. METHODS: We retrospectively identified patients with fracture in an extremity in Japanese Trauma Data Bank from 2004 to 2019. We included adult patients who underwent open reduction and internal fixation for extremity injury before any other surgical intervention and excluded those who arrived with cardiac arrest. Several clinical parameters, such as age, vital signs, abbreviated injury scale (AIS) in the chest, and injury severity score (ISS), were examined with multivariate logistic regression models to predict in-hospital mortality, and then integrated into a scoring system based on each odds ratio. To determine a cut-off value of the scoring system for safe early definitive surgery, in-hospital mortality and/or postoperative complications were compared between patients who underwent definitive fixation within 24 h of injury and patients who did not in subgroups based on the scores. RESULTS: Of 50,631 patients eligible for this study, 16,119 (31.8%) underwent early definitive fixation. A 0-15 scoring system with parameters including age >70 years, GCS <8, systolic blood pressure <90 mmHg, AIS in the chest ≥3, ISS ≥20, and transfusion requirement within 24 h of arrival was developed. At scores ≥10, early definitive fixation was found to be significantly associated with high in-hospital mortality, and at scores <10, in-hospital mortality was comparable between the two groups. CONCLUSIONS: We integrated clinical parameters into the scoring system with a scale of 0-15 and determined that a score of 10 is the cut-off score. We determined that patients with a score <10 can safely undergo early definitive fixation.

Patient body mass index modifies the association between waiting time for hip fracture surgery and in-hospital mortality: A multicenter retrospective cohort study.

BACKGROUND: Patient body mass index (BMI) plays an important role in stress exposure, especially in elderly patients with hip fracture. However, how BMI modifies the relationship between the waiting time for surgery and mortality remains unclear. METHODS: We investigated the association between waiting time and mortality using a nationwide multicenter database of patients undergoing hip fracture surgery. The primary outcome was in-hospital mortality and secondary outcomes were complications. We performed prespecified subgroup analysis with stratification by BMI. RESULTS: Overall, 305,846 patients (mean age, 83.5; standard deviation [SD], 8.2); women, 79.5% (n = 243,214) were included in our study. A cubic spline curve revealed two inflection points in the association between waiting time and mortality, and we statistically divided patients into three groups accordingly: the reference group (80,110 patients [26.2%] who waited 1 day for surgery), the delayed group (184,778 patients [60.4%] who waited 2-6 days for surgery), and the extremely delayed group (40,958 patients [13.4%] who waited more than 6 days for surgery). Multivariable logistic regression models showed that the odds of mortality in the delayed group was 14% higher than that in the reference group (adjusted odds ratio [aOR], 1.14; p = 0.002), whereas the odds of mortality in the extremely delayed group was 52% higher than that of the reference group (aOR, 1.52; p < 0.001). Patients with lower BMI were more negatively affected by delayed surgery compared to patients with normal BMI (p for interaction = 0.002). Respiratory disorders were most frequent and the spline curve was accordant with in-hospital mortality. CONCLUSION: Patients underwent surgery within 1 day, particularly with lower BMI, had a lower mortality than normal BMI. To optimize limited health care resource, patient's BMI should be considered for hip fracture management, and further investigation in prospective study should be needed to address causal relationship. LEVEL OF EVIDENCE: Therapeutic Level III.

Residual coracoclavicular separation after plate fixation for distal clavicle fractures: comparison between fracture patterns.

BACKGROUND: Plate fixation is an established treatment for Neer type II and V distal clavicle fractures; however, residual coracoclavicular (C-C) separation after osteosynthesis for unstable distal clavicle fractures has rarely been discussed. This study aimed to reveal the extent of postoperative C-C separation after plate fixation for distal clavicle fractures and to evaluate the relationship between residual C-C separation and the risk of postoperative complications. METHODS: We retrospectively reviewed 60 patients with a displaced distal clavicle fracture that was treated with a Scorpion plate without C-C reconstruction and successfully united. Distal clavicle fractures were divided as per the Neer classification into type IIA (12 patients), IIB (36 patients), and V (12 patients) groups. The modified C-C distance ratio at the time of injury and after bone union, and the postoperative complications (plate-related pain, delayed union, infection, and contracture) were compared among the three groups. RESULTS: The mean postoperative modified C-C distance ratio was 115.0% ± 12.0%; this ratio was significantly larger in the type IIB and V groups than in the type IIA group (P = .021 and P = .006, respectively). However, there was no significant difference in the frequency of postoperative complications among the three groups. CONCLUSIONS: Our study demonstrated that a certain degree of C-C separation remained after plate fixation for Neer type II and V distal clavicle fractures, even when bone union was achieved. The postoperative residual C-C separation was greater for the type IIB and V groups than for the type IIA group; however, this difference may not affect postoperative complications.

Compressive mechanical stress enhances susceptibility to interleukin-1 by increasing interleukin-1 receptor expression in 3D-cultured ATDC5 cells.

BACKGROUND: Mechanical overload applied on the articular cartilage may play an important role in the pathogenesis of osteoarthritis. However, the mechanism of chondrocyte mechanotransduction is not fully understood. The purpose of this study was to assess the effects of compressive mechanical stress on interleukin-1 receptor (IL-1R) and matrix-degrading enzyme expression by three-dimensional (3D) cultured ATDC5 cells. In addition, the implications of transient receptor potential vanilloid 4 (TRPV4) channel regulation in promoting effects of compressive mechanical loading were elucidated. METHODS: ATDC5 cells were cultured in alginate beads with the growth medium containing insulin-transferrin-selenium and BMP-2 for 6 days. The cultured cell pellet was seeded in collagen scaffolds to produce 3D-cultured constructs. Cyclic compressive loading was applied on the 3D-cultured constructs at 0.5 Hz for 3 h. The mRNA expressions of a disintegrin and metalloproteinases with thrombospondin motifs 4 (ADAMTS4) and IL-1R were determined with or without compressive loading, and effects of TRPV4 agonist/antagonist on mRNA expressions were examined. Immunoreactivities of reactive oxygen species (ROS), TRPV4 and IL-1R were assessed in 3D-cultured ATDC5 cells. RESULTS: In 3D-cultured ATDC5 cells, ROS was induced by cyclic compressive loading stress. The mRNA expression levels of ADAMTS4 and IL-1R were increased by cyclic compressive loading, which was mostly prevented by pyrollidine dithiocarbamate. Small amounts of IL-1ß upregulated ADAMTS4 and IL-1R mRNA expressions only when combined with compressive loading. TRPV4 agonist suppressed ADAMTS4 and IL-1R mRNA levels induced by the compressive loading, whereas TRPV4 antagonist enhanced these levels. Immunoreactivities to TRPV4 and IL-1R significantly increased in constructs with cyclic compressive loading. CONCLUSION: Cyclic compressive loading induced mRNA expressions of ADAMTS4 and IL-1R through reactive oxygen species. TRPV4 regulated these mRNA expressions, but excessive compressive loading may impair TRPV4 regulation. These findings suggested that TRPV4 regulates the expression level of IL-1R and subsequent IL-1 signaling induced by cyclic compressive loading and participates in cartilage homeostasis.

Overexpression of Interleukin-1α Suppresses Liver Metastasis of Lymphoma: Implications for Antitumor Effects of CD8+ T-cells.

Interleukin (IL)-1 plays a key role in carcinogenesis, tumor progression, and metastasis. Although IL-1 may enhance the expansion of CD8+ T-cells, the pathological contribution of IL-1-activated CD8+ T-cells to tumor metastasis remains unclear. This study used a liver metastasis model of the EL4 T-cell lymphoma cells transplanted into human IL (hIL)-1α conditional transgenic (hIL-1α cTg) mice. Overproduction of hIL-1α suppressed both macroscopic and histological liver metastasis of EL4 T-cell lymphoma. The hIL-1α-induced inflammatory state increased the number of CD8+ T-cells both within and around metastatic tumors. Moreover, larger numbers of CD8+ T-cells showed greater infiltration of liver blood vessels in hIL-1α cTg mice than in control wild-type mice. Terminal deoxynucleotidyl transferase dUTP nick-end labeling staining of liver tissue from hIL-1α cTg mice indicated increased apoptosis of cells in the tumor. Localization of apoptosis cells resembled that of CD8+ T-cells. In addition, cytotoxicity assay showed that CD8+ T-cell counts from tumor-bearing hIL-1α cTg mice correlated with cytotoxicity against EL4. In summary, IL-1α suppresses lymphoma metastasis, and IL-1α-activated CD8+ T-cells may play important roles in inhibiting both tumor metastasis and metastatic tumor growth.

Who Will Benefit From Kinematically Aligned Total Knee Arthroplasty? Perspectives on Patient-Reported Outcome Measures.

BACKGROUND: Indications for kinematically aligned total knee arthroplasty (KA-TKA) have remained contentious. This study aimed at exploring preoperative characteristics of patients who were suitable for and benefited from KA-TKA, based on the assessment of patient-reported outcome measures (PROMs). METHODS: Subjects comprised 100 patients undergoing KA-TKA and 100 patients undergoing mechanically aligned (MA)-TKA due to end-stage osteoarthritis. Bone cuts were performed using portable navigation systems according to 3D planning data from computed tomography. At 2 years postoperatively, all 200 patients were assessed for PROMs, including Knee Society Score 2011, pain catastrophizing scale, and pain DETECT score. Multiple regression analysis was performed with activity subscore set as a dependent variable. Principal component analysis was used to evaluate patient satisfaction and function components transformed from the 3 PROMs and to compare these components between KA-TKA and MA-TKA. RESULTS: Male gender or use of KA technique positively affected advanced activity score, whereas age, body mass index, preoperative pain DETECT score, and preoperative femorotibial angle showed negative effects. In principal component analysis, 38 KA-TKA patients achieved a higher function score, with satisfaction scores comparable to those from MA-TKA. These 38 patients were characterized by a higher percentage of males, younger age, and higher preoperative total activity score. CONCLUSION: From the perspective of PROMs, KA-TKA should be favored over MA-TKA for young active males, because these patient groups achieved higher functional activity when undergoing KA-TKA.

Damage control orthopedics and decreased in-hospital mortality: A nationwide study.

INTRODUCTION: While various strategies of fracture fixation in trauma victims have been discussed, the effect of damage control orthopedics (DCO) on significant clinical outcome is inconclusive. We examined the mortality of patients managed with DCO, comparing those without DCO, using a nationwide trauma database. PATIENTS AND METHODS: We retrospectively identified patients with extremity injury, defined as patients with an Abbreviated Injury Scale (AIS) of ≥2 in an upper or lower extremity, in the database that included more than 200 major hospitals from 2004 to 2016. We included those who were age ≥15 years and underwent ORIF. Patients with missing survival data or invalid vital signs at hospital arrival were excluded. Patient data were divided into DCO or non-DCO groups, and propensity scores were developed to estimate the probability of being assigned to the DCO group, using multivariate logistic regression analyses adjusted for known survival predictors, such as age, vital signs at arrival, Abbreviated Injury Scale in extremity, ISS, presence of vascular injury, surgical procedure before fracture treatment, and transfusion requirement. The primary outcome, in-hospital mortality, was compared between the two groups after propensity score matching. Survival analyses were performed, and hazard ratio was adjusted according to age, systolic blood pressure on arrival, and Injury Severity Score. RESULTS: Of the 19,319 patients included in this study, 4407 (22.8%) underwent DCO. After the propensity score matching, 3858 pairs were selected. In-hospital mortality was significantly lower among patients in the DCO than those in the non-DCO groups (40 [1.0%] vs. 66 [1.7%]; odds ratio = 0.60; 95% confidence interval [CI] = 0.41-0.89; P = 0.01). Survival analyses showed that DCO was independently associated with decreased mortality in patients with extremity injury (adjusted hazard ratio = 0.30; 95% CI = 0.20-0.46; P < 0.01). CONCLUSIONS: DCO was associated with decreased in-hospital mortality in patients with major fractures. Further clinical study on DCO by selecting patient population should be considered eventually to develop an appropriate strategy for major fractures.

The effects of barbed suture on watertightness after knee arthrotomy closure: a cadaveric study.

BACKGROUND: Wound closure is one of the crucial aspects of total knee arthroplasty (TKA) for patients who perform high-flexion activities of daily living, because the joint capsule is highly stretched and integrity of the arthrotomy closure must be maintained. Watertightness of the knee joint is a different aspect of the repair integrity of arthrotomy closure and is being noticed with increasing usage of the drain clamp method for blood management after TKA. Recently, the barbed knotless suture has been growing in popularity as a strong, secure closure appropriate for high-tension areas, such as the fascia and joint capsule. The purpose of this study was to compare the barbed knotless suture with simple interrupted suture in cadaveric knees. METHODS: Nine fresh-frozen cadaveric lower extremities were used. After placing a parapatellar incision and setting a closed suction drain, arthrotomies were closed randomly using three suture materials: simple interrupted absorbable suture (No. 0 PDS, group C); or a single running knotless barbed suture Stratafix with 8N (group BS-8N) or 15N (group BS-15N) of tension. After arthrotomy closure, saline was injected in a retrograde manner into the joint through a drain until saline started to leak from the joint. Peak values for intra-articular pressure and infusion volume in each group were recorded and compared. RESULTS: Mean infusion volumes were 13.0 ± 7.2 ml, 38.6 ± 10.7 ml, and 5.1 ± 2.5 ml in groups BS-8N, BS-15N, and C, respectively. Mean intra-articular pressures were 0.67 ± 0.47 kPa, 9.44 ± 4.55 kPa, and 0.56 ± 0.44 kPa in groups BS-8N, BS-15N, and C, respectively. Infusion volume and joint internal pressure were significantly higher in group BS-15N than in groups BS-8N (p = 0.008) or C (p = 0.04). CONCLUSIONS: Barbed suture with 15N appears appropriate for maintaining maximal watertightness after knee joint capsule closure, offering successful drain clamping, higher resistance to early mobilization protocols, and subsequent achievement of early deep knee flexion after TKA.

Arthroscopic Treatment of Tibial Eminence Avulsion Fracture With Suture Tensioning Technique.

Although a tibial eminence avulsion fracture is a rare knee injury, it can result in some complications such as nonunion, limited range of motion, and anterior instability of the knee if the displaced fracture is not well reduced. Arthroscopic procedures for this fracture have been commonly performed in recent years. In patients with small fragments, a pullout operation is usually performed, but arthroscopic suture reduction is technically difficult. In addition, anterior instability of the knee may remain even if the fragment is well reduced at the time of the surgical procedure. Generally, surgeons are concerned about anatomic reduction compared with appropriate tensioning during surgery. Therefore, one of the key points to avoid remaining anterior instability of the knee is to obtain and maintain appropriate tensioning. The purpose of this article is to present an easy and safe technique for acquisition of appropriate tensioning using a tensioning device for tibial eminence avulsion fractures. Although it has limitations, this technique can facilitate the reduction of tibial eminence avulsion fractures and appropriate tensioning of the anterior cruciate ligament.

Arthroscopically Assisted Retrograde Intramedullary Nailing for Periprosthetic Fracture of the Femur after Posterior-Stabilized Total Knee Arthroplasty.

Retrograde intramedullary nailing (RIMN) has been used for periprosthetic fracture of the distal femur after total knee arthroplasty (TKA), yielding good fracture union rates and satisfactory outcomes. However, RIMN for posterior-stabilized- (PS-) TKA risks malpositioning the entry point and disturbing the post of the tibial insert, and the surgeon therefore usually requires knee joint arthrotomy. We report a case of a 79-year-old male who was involved in bicycle accident resulting in periprosthetic fracture of the distal femur after PS-TKA. We performed osteosynthesis with arthroscopically assisted RIMN to define an appropriate entry point. RIMN for posterior-stabilized- (PS-) TKA risks malpositioning the entry point and disturbing the post of the tibial insert. Because arthroscopy can directly visualize the entry point and the tibial post without arthrotomy, arthroscopically assisted RIMN offers a useful technical option for periprosthetic fracture of the distal femur after PS-TKA.

Joint Line Modification in Kinematically Aligned Total Knee Arthroplasty Improves Functional Activity but Not Patient Satisfaction.

BACKGROUND: Joint line modification in kinematically aligned total knee arthroplasty (KA-TKA) is attracting attention in expectation of optimizing patient satisfaction after TKA. This study aimed to examine the effects of joint line modification on Pain Catastrophizing Scale (PCS), painDETECT score, and new Knee Society Score (KSS) 2011, all of which are robustly related to patient satisfaction. METHODS: The study enrolled 45 knees of 45 patients undergoing KA-TKA and a matched group of 45 knees of 45 patients undergoing mechanically aligned (MA) TKA as controls. At a mean of 31.6 months after TKA, new KSS 2011, PCS, and painDETECT score were assessed and compared between KA- and MA-TKA. Data from all 90 patients were pooled into one group for secondary multiple regression analysis to identify postoperative variables affecting patient satisfaction. RESULTS: Assessment with new KSS 2011 showed no significant differences between the 2 TKAs preoperatively, but functional activity score was significantly higher with KA-TKA than with MA-TKA postoperatively (P = .047). Among the 4 categories of functional activity score, advanced activity score was significantly higher with KA-TKA than with MA-TKA (P = .003). Of the 5 advanced activities, the score for climbing ladder/step stool was significantly greater with KA-TKA (P = .004). KA-TKA failed to influence patient satisfaction score. Multiple regression analysis revealed that standard activity score and PCS affected patient satisfaction positively and negatively, respectively. CONCLUSION: Joint line modification in KA-TKA improved functional activity but not patient satisfaction. PCS was a key element negatively affecting patient satisfaction.

A Heart-shaped Sleeve Simplifies Intramedullary Tibial Nail Insertion when Using the Suprapatellar Approach.

The suprapatellar approach for intramedullary tibial nailing has become widely accepted over the past decade. A round sleeve is passed beneath the patella to protect the surface of the patellofemoral joint (PFJ). However, the round sleeve cannot be easily stabilized in the PFJ because it does not conform to the shape of the patellar apex. Consequently, we produced a heart-shaped sleeve to simplify the insertion of the entry sleeve during the suprapatellar approach. Using the new sleeve, the following procedure is used: (1) make a longitudinal 4 cm skin incision proximal to the patella to reach the PFJ, (2) insert the guide pin manually to the ventral edge of the tibial plateau, (3) insert the cannulated trocar along the guide pin, (4) insert the heart-shaped sleeve along the cannulated trocar, (5) remove the cannulated trocar, (6) ream the entry point through the heart-shaped sleeve. Then, continue insertion of the nail in the standard manner. Among 44 patients (29 men, mean age 45.6 years, range 26-87 years) with tibial fractures treated between 2010 and 2015, the first 18 consecutive cases were performed using a round sleeve and the rest were performed using the heart-shaped sleeve. The surgery time until entry reaming commenced was 8.9 min (range 6-12 min) using the round sleeve and 6.2 min (range 3-12 min) using the heart-shaped sleeve (P < 0.05). The heart-shaped sleeve is easily stabilized in the PFJ and greatly simplifies the intramedullary nailing of tibial shaft fractures using the suprapatellar approach.

Surgical Technique to Bring Down the Patellar Height and to Reconstruct the Tendon for Chronic Patellar Tendon Rupture.

Although surgical treatment is the gold standard for chronic patellar tendon rupture, the technique of patellar tendon reconstruction is still difficult. Basically, good clinical results of surgical repair for acute patellar tendon rupture have been reported. However, the results of reconstructive surgery for chronic patellar tendon rupture are still inconsistent. Some surgical options have been previously reported. For example, surgeons need to choose between 1- and 2-stage reconstruction. Furthermore, contralateral bone-tendon-bone graft, ipsilateral semitendinosus tendon graft, Achilles tendon allograft, and an artificial ligament have been used to reconstruct the patellar tendon. Generally, surgeons are concerned about postoperative complications, including loss of knee flexion, quadriceps weakness, and wound problems. One of the key points to avoid these complications is to improve proximal patellar migration. The purpose of this article is to present an easy and safe technique to bring down the patellar height with polyethylene tape and to reconstruct the patellar tendon with an artificial ligament. Although it has limitations, the described technique can facilitate reconstruction of chronic patellar tendon rupture.

Factors influencing graft impingement on the wall of the intercondylar notch after anatomic double-bundle anterior cruciate ligament reconstruction.

BACKGROUND: Anatomic placement of the bone tunnel reportedly reduces impingement of the graft with the intercondylar roof, but as a trade-off, the risk of impingement with the lateral wall of the intercondylar notch would increase instead in anatomic double-bundle anterior cruciate ligament (ACL) reconstruction. PURPOSE: The 2 grafts for the anteromedial bundle (AMB) and posterolateral bundle (PLB) were separately analyzed for the frequency of and risk factors for graft impingement on the wall of the intercondylar notch. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: A total of 51 patients (53 knees) who underwent primary anatomic double-bundle ACL reconstruction were enrolled. Based on the graft orientation plane reconstructed with 3-dimensional imaging software, graft-wall impingement was defined as overlap between the lateral wall of the notch and the line connecting each center of the intra-articular apertures of the femoral and tibial bone tunnels. The rate of wall impingement was assessed for each bundle. Parameters for bone tunnel positioning in the femur and tibia, notch width index, and knee joint rotation angle were compared between patients with and without wall impingement. The most important risk factors for wall impingement were assessed by logistic regression analysis. RESULTS: Wall impingement for the AMB was observed in 22 knees (42%), whereas no patients exhibited wall impingement for the PLB. Regarding femoral bone tunnel positioning according to the quadrant method, the AMB bone tunnel was placed significantly higher in impingement-positive patients than in impingement-negative patients (P = .03). Regarding tibial tunnel positioning, the tunnel was placed significantly more anteriorly (P = .02) and laterally (P = .02) in the impingement-positive group than in the impingement-negative group. Bone tunnels positioned 48% to 50% from the medial border of the tibia demonstrated a 100% incidence of wall impingement. Based on logistic regression analysis, lateral deviation of the AMB tibial bone tunnel was significantly associated with wall impingement (odds ratio, 1.403; P = .048). CONCLUSION: The tibial bone tunnel position in the coronal orientation was most likely associated with wall impingement. Considering that tibial bone tunnels are generally created with the knee in 90° of flexion and move laterally as the knee extends because of screw-home movement, the AMB bone tunnel for the tibia should be positioned as medially as possible within its footprint to minimize the risk of wall impingement after anatomic double-bundle ACL reconstruction.

Severe valgus deformity of the knee with permanent patellar dislocation associated with melorheostosis: a case report and review of the literature.

We present a case of an 8-year-old boy diagnosed with melorheostosis who was suffering from severe genu valgum, permanent dislocation of the patella, knee flexion contracture and leg length shortening. Soft tissue contracture of the limb and subsequent joint deformities were reported to represent clinical manifestations of pediatric melorheostosis. As the epiphyseal plate had not closed, patellar reduction was achieved by soft tissue surgical stabilization, including lateral retinacular release, medial retinaculum plication, and transfer of the lateral half of the patellar tendon. At 4 years postoperatively, as a result of improved limb alignment and knee flexion contracture, the leg length shortening has improved, and the patient does not limp and participates in sports activities. Surgical intervention should be performed as early as possible, because genu valgum and external rotation of the tibia may deteriorate with age, rendering the patellar dislocation irreversible in patients with melorheostosis before epiphyseal closure.

Lateral patellar retinaculum reconstruction for medial patellar instability following lateral retinacular release: a case report.

Lateral retinacular release is still being performed in patients with recurrent patellar dislocation as an additional procedure with distal realignment or medial patellofemoral ligament (MPFL) reconstruction. However, consensus remains lacking regarding suitable indications for lateral retinacular release. A 20-year-old woman presented with patellar instability in both medial and lateral directions after undergoing lateral retinacular release with MPFL reconstruction. She displayed inherent systemic joint laxity meeting all seven Carter-Wilkinson criteria. Simultaneous MPFL revision and lateral retinaculum reconstruction successfully improved patellar instability in both directions. This case provides an example of iatrogenic medial patellar instability after failed lateral retinacular release.