Static Balance in Participants with Temporomandibular Joint Disc Displacement without Reduction Versus Healthy Participants: A Cross-Sectional Study.

BACKGROUND There is no consensus on the association between body posture and temporomandibular disorders (TMDs). This study aimed to assess differences in static balance between healthy participants and patients with temporomandibular joint disc displacement without reduction. MATERIAL AND METHODS Sixteen patients with temporomandibular joint disc displacement without reduction and 14 healthy participants were included. Static balance tests were performed in the rest and "cotton rolls" (participants biting 2 cotton rolls with their upper and lower teeth) mandibular positions. The mean body's center of gravity (COG) sway velocity was tested in each mandibular position on a firm surface with and without eyes open and on a foam surface with and without eyes open. RESULTS The COG sway velocity did not differ between the TMD and healthy groups regarding mandibular position or testing condition (P>0.05). However, in the control group, the COG sway velocity in the mandibular rest position was significantly higher than that in the "cotton rolls" mandibular position when standing on a foam surface with the eyes closed (P=0.024). In the TMD group, there was no difference in the COG sway velocity between the 2 mandible positions under any condition (P>0.05). CONCLUSIONS This study provides new evidence for static balance alterations in patients with temporomandibular joint disc displacement without reduction. Further studies are needed to investigate postural control changes in patients with arthrogenous TMDs. This study was registered in the Chinese Clinical Trial Registry (no. ChiCTR1800018369).

Effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions: A scoping review.

BACKGROUND: In the field of orthotics, the use of three-dimensional (3D) technology as an alternative to the conventional production process of orthoses is growing. PURPOSE: This scoping review aimed to systematically map and summarize studies assessing the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions, and to identify knowledge gaps. METHODS: The Cochrane Library, PubMed, EMBASE, CINAHL, Web of Science, IEEE, and PEDro were searched for studies of any type of 3D-printed orthoses for traumatic and chronic hand conditions. Any outcome related to the effectiveness of 3D-printed orthoses was considered. Two reviewers selected eligible studies, charted data on study characteristics by impairment type, and critically appraised the studies, except for case reports/series. RESULTS: Seventeen studies were included: four randomized controlled trials, four uncontrolled trials, four case series and five case reports. Only three studies had a sample size >20. Impairments described were forearm fractures (n = 5), spasticity (n = 5), muscle weakness (n = 4), joint contractures (n = 2) and pain (n = 1). Four poor to fair quality studies on forearm fractures supported the effectiveness of 3D-printed orthoses on hand function, functionality, and satisfaction. One good quality study on spasticity demonstrated the effectiveness of 3D-printed orthoses on hand function. One poor quality pain study reported limited positive effects on satisfaction. Studies on muscle weakness and joint contractures showed no benefits. CONCLUSION: Current literature addressing the effectiveness of 3D-printed orthoses for traumatic and chronic hand conditions consists primarily of small and poor methodological quality studies. There is a need for well-designed controlled trials including patient-related outcomes, production time and cost analyses.

Predisposing conditions for condylar sag after intraoral vertical ramus osteotomy.

Intraoral vertical ramus osteotomy (IVRO) is used to treat mandibular prognathism and temporomandibular disorders. However, the improvement of temporomandibular disorders after IVRO is considered to be due to the anterior and downward movement of the mandibular condyle, which may lead to condylar sag, and in the worst case, condylar luxation. In this retrospective cohort study, we examined factors potentially associated with condylar sag. Univariate analysis indicated that condylar sag was significantly associated with the following factors: magnitude of setback (P = 0.001), less than 3 mm setback (P < 0.001), presence of temporomandibular joint (TMJ) symptoms (P = 0.002), Wilkes classification (P = 0.039), occlusal cant correction ≥ 2 mm (P = 0.018), and mandibular condyle deformation (P < 0.001). Setback magnitude (P = 0.032) and TMJ symptoms (P = 0.007) remained significant in the multivariate analysis. In the receiver operating characteristic curve, the setback magnitude cut-off value for condylar sag after IVRO was 3.25 mm. Thus, the incidence of condylar sag after IVRO is increased with a smaller setback magnitude (≤ 3.25 mm) and the presence of TMJ symptoms. These factors should be evaluated by surgeons during treatment planning for IVRO to estimate condylar sag, and it may be possible to predict the risk of condylar luxation.

Popliteal scoring assessment for vascular extremity injuries in trauma study.

OBJECTIVE: Traumatic popliteal vascular injuries are associated with the highest risk of limb loss of all peripheral vascular injuries. A method to evaluate the predictors of amputation is needed because previous scores could not be validated. In the present study, we aimed to provide a simplified scoring system (POPSAVEIT [popliteal scoring assessment for vascular extremity injuries in trauma]) that could be used preoperatively to risk stratify patients with traumatic popliteal vascular injuries for amputation. METHODS: A review of patients sustaining traumatic popliteal artery injuries was performed. Patients requiring amputation were compared with those with limb salvage at the last follow-up. Of these patients, 80% were randomly assigned to a training group for score generation and 20% to a testing group for validation. Significant predictors of amputation (P < .1) on univariate analysis were included in a multivariable analysis. Those with P < .05 on multivariable analysis were assigned points according to the relative value of their odds ratios (ORs). Receiver operating characteristic curves were generated to determine low- vs high-risk scores. An area under the curve of >0.65 was considered adequate for validation. RESULTS: A total of 355 patients were included, with an overall amputation rate of 16%. On multivariate regression analysis, the risk factors independently associated with amputation in the final model were as follows: systolic blood pressure <90 mm Hg (OR, 3.2; P = .027; 1 point), associated orthopedic injury (OR, 4.9; P = .014; 2 points), and a lack of preoperative pedal Doppler signals (OR, 5.5; P = .002; 2 points [or 1 point for a lack of palpable pedal pulses if Doppler signal data were unavailable]). A score of ≥3 was found to maximize the sensitivity (85%) and specificity (49%) for a high risk of amputation. The receiver operating characteristic curve for the validation group had an area under the curve of 0.750, meeting the threshold for score validation. CONCLUSIONS: The POPSAVEIT score provides a simple and practical method to effectively stratify patients preoperatively into low- and high-risk major amputation categories.

Isolated Shear Fracture of the Metatarsal Head in Lesser Toes Treated With ORIF: Case Series.

BACKGROUND: Isolated shear fractures of a metatarsal head in the lesser toes are rare in clinical practice. We report the clinical and imaging characteristics, and treatment results, of these fractures. METHODS: A retrospective consecutive case-series study was performed on 7 patients with symptomatic isolated shear fracture of a metatarsal head in the lesser toes who were operatively treated using open reduction and internal fixation (ORIF). Radiographs and computed tomographic (CT) scans of the patients were analyzed. The American Orthopaedic Foot & Ankle Society-lesser metatarsophalangeal-interphalangeal (AOFAS-LMI) score, visual analog scale (VAS) score, and passive dorsiflexion range of motion (ROM) of the metatarsophalangeal (MTP) joint were determined preoperatively and at final follow-up. Postoperative complications were also recorded. RESULTS: There were 5 males and 2 females, with a mean age of 21 years (range, 16-36) at the time of surgery. Four fractures occurred at the fourth metatarsal. There were 3 chronic cases, 1 was not diagnosed initially; the other 2 failed conservative treatment. The main symptom of the chronic fractures was limited dorsiflexion at the MTP joint. Preoperative radiographs and CT scans revealed dorsal displacement of the fragment without dislocation of the MTP joint. At the final follow-up (mean, 17.4 months; range 9-27), the AOFAS-LMI scores had improved from 70.6 (range, 59-79) preoperatively to 93.3 (range, 92-100) (P = .001). VAS scores showed a decrease in pain from 4.0 to 0.0 (P = .016). Mean passive dorsiflexion ROM of the MTP joint improved significantly from 8.6 degrees preoperatively to 35.7 degrees at final follow-up (P < .001). All patients returned to their respective preinjury activity levels. CONCLUSION: Patients with an acute or chronic isolated shear fracture of a metatarsal head in the lesser toes treated by ORIF achieved good short-term clinical and radiologic outcomes. LEVEL OF EVIDENCE: Level IV, retrospective case series.

What Factors Are Associated with Reoperation After Operative Treatment of Terrible Triad Injuries?

BACKGROUND: Terrible triad injuries of the elbow, consisting of posterior ulnohumeral joint dislocation with associated fractures of the radial head and coronoid process, are challenging injuries due to the difficulty in restoring stability to the joint surgically while also attempting to allow early ROM to prevent stiffness. Furthermore, complications are both debilitating and relatively common, frequently requiring reoperation. QUESTIONS/PURPOSES: (1) What patient-, injury-, or surgery-related factors are associated with reoperation after surgical treatment of terrible triad injuries of the elbow? (2) What are the most common causes of reoperation after these injuries? METHODS: Between January 2000 and June 2017, we identified 114 patients who had surgery for terrible triad injuries at two tertiary-care referral centers. Of those, 40% (46 of 114) were lost to follow-up before 1 year, and an additional 5% (6 of 114) were excluded because they underwent the index surgery at an outside institution (n = 4) or underwent closed reduction with or without percutaneous pinning (n = 2). That left 62 patients for analysis in this retrospective study with a minimum of 1-year follow-up (median 22 months; range 12 to 65) or who met the endpoint of reoperation before 1 year. During the study period, indications for surgical treatment of terrible triad injuries of the elbow included joint incongruity or instability precluding early ROM. In our study cohort, 45% (28 of 62) underwent reoperation. Indications for reoperation after surgical treatment included stiffness that interfered with activities of daily life, symptomatic prominent hardware, ulnar neuropathy, instability of the elbow joint at rest or with range of motion, and infection. Patient-related (such as age, sex, race), injury-related (for example, ipsilateral extremity fracture, open fracture), and surgery-related factors (for instance, time to surgery, radial head treatment) as well as outcomes were collected by the treating surgeon at the time of follow-up and ascertained using chart review. The primary outcome measure was reoperation after surgical treatment of a terrible triad injury of the elbow. Bivariate analysis was used to assess whether explanatory variables were associated with reoperation after surgical treatment of terrible triad injuries of the elbow. RESULTS: Of the patient-, injury-, and surgery-related factors that were analyzed, only radial head treatment was associated with an increased reoperation risk (p = 0.03). No other variable met criteria for inclusion in our multivariable logistic regression model (p < 0.10), and therefore, a multivariable logistic regression model was not performed. The most common indication for reoperation was stiffness (21% [13 of 62 patients]), followed by symptomatic hardware (18% [11 of 62 patients]), nerve symptoms (ulnar neuropathy 16% [10 of 62 patients] and incisional neuroma 2% [1 of 62 patients]), instability (6% [4 of 62 patients]), and wound problems (infection 2% [1 of 62 patients]). CONCLUSION: The reoperation risk after surgical treatment of terrible triad injuries of the elbow is high. No patient- or injury-related factors were associated with the reoperation risk. Based on our finding, we recommend fixation of radial head fractures in these injuries when feasible and compatible with early postoperative motion, and we suggest the use of radial head excision or arthroplasty as a secondary options. LEVEL OF EVIDENCE: Level III, therapeutic study.

Is C1-C2 Reduction and Fixation A Good Choice in the Treatment of Recurrent Chiari-Like Symptoms With Syringomyelia?

BACKGROUND: Foramen magnum decompression (FMD) is the first-choice treatment for Chiari malformation (CM). However, it has been suggested that cerebellar herniation and syringomyelia occur as a natural protective event to prevent neural damage caused by atlantoaxial instability. It is argued that treating instability is the main treatment. Positive results of atlantoaxial fusion have been reported in the literature, but there are no studies including the results of atlantoaxial fusion as the second treatment in patients in whom classical decompression failed. In our study, we report the results of these patients to help in the selection of treatment and we present our treatment algorithm for CM with syringomyelia. METHODS: Thirteen patients who had undergone FMD and duraplasty due to CM and syringomyelia in our clinics and who had recovered clinically and radiologically but had recurrent complaints during long-term follow-up were evaluated. C1-C2 distraction and fusion were performed. We evaluated these patients radiologically and clinically. RESULTS: The mean age of the 13 patients was found to be 32.4 years. Male to female ratio was 6:7. The complaints recurred after an average of 2.1 years. Also, 3 cases were presented with their clinical characteristics and radiologic findings. CONCLUSIONS: FMD may fail even with duraplasty, and treatment of CM in recurrent cases is still controversial. Recently, atlantoaxial instability has been reported to be the main pathology of CM, and the cure for pathology is to treat instability. Recurrent CMs with syringomyelia in which FMD has failed should be treated by atlantoaxial fixation.

Biomechanical Factors in Stability of the Forearm.

In the forearm, ligaments and joints act in unison to facilitate placement of the hand in 3-dimensional space and transmit loads across the upper extremity. Intricate, effective forearm stabilizers facilitate physiologic motions and restrict abnormal ones. The proximal radioulnar joint, interosseous ligament complex, and distal radioulnar joint work together to ensure the forearm is stable. Each ligament and joint is designed to leverage its biomechanical advantages. Damage destabilizes the synergy of the forearm and results in debilitating injury patterns. Physicians need to understand how all these structures work together to be able to quickly diagnose and treat these forearm injuries.

Peroneal Tendinosis and Subluxation.

Peroneal tendinosis and subluxation are lifestyle-limiting conditions that can worsen if not properly diagnosed and treated. Adequate knowledge of ankle anatomy and detailed history and comprehensive physical examination is essential for diagnosis. Peroneal tendinopathy is likely to result from overuse, whereas subluxation often precipitates from forceful contraction of peroneals during sudden dorsiflexion while landing or abruptly stopping. In athletes, conservative measures remain first-line treatment of tendinopathy, but surgery is often immediately indicated in cases of recurrent symptomatic subluxation or dislocation. Surgical technique varies on the type, mechanism, and severity of injury, but most procedures have a high success rate.

A Case of Long-standing Temporomandibular Joint Dislocation: Restoration of Oral Function Following Condylectomy.

BACKGROUND: Temporomandibular joint (TMJ) dislocation can be categorized into three groups: acute, habitual or recurrent, and long-standing. Long-standing TMJ dislocation refers to a condition that persists for more than one month without reduction. Long-standing dislocation of the TMJ is rare and the most challenging and difficult to treat of the three. CASE REPORT: The present case study relates to a 53-year-old woman with long-standing TMJ dislocation of a year's duration who presented for treatment. Due to this condition, she was unable to take food orally, and nutrition was managed by gastrostomy tube feeding. She also suffered from schizophrenia and had been admitted to a closed hospital. Bilateral mandibular condylectomy was performed, restoring oral function. However, post-reduction, an open bite remained, restricting the types of food that she could eat. Additional intermaxillary fixation and intermaxillary traction would have been required for an optimal outcome, but they were not possible for this patient. CONCLUSION: Despite an inability to provide comprehensive treatment, due to patient-related factors, occlusal and masticatory functions were restored to adequate levels following bilateral condylectomy alone. This enabled oral feeding and improved her quality of life.

Consensus on Indications for Isolated Subtalar Joint Fusion and Naviculocuneiform Fusions for Progressive Collapsing Foot Deformity.

RECOMMENDATION: Peritalar subluxation represents an important hindfoot component of progressive collapsing foot deformity, which can be associated with a breakdown of the medial longitudinal arch. It results in a complex 3-dimensional deformity with varying degrees of hindfoot valgus, forefoot abduction, and pronation. Loss of peritalar stability allows the talus to rotate and translate on the calcaneal and navicular bone surfaces, typically moving medially and anteriorly, which may result in sinus tarsi and subfibular impingement. The onset of degenerative disease can manifest with stiffening of the subtalar (ST) joint and subsequent fixed and possibly arthritic deformity. While ST joint fusion may permit repositioning and stabilization of the talus on top of the calcaneus, it may not fully correct forefoot abduction and it does not correct forefoot varus. Such varus may be addressed by a talonavicular (TN) fusion or a plantar flexion osteotomy of the first ray, but, if too pronounced, it may be more effectively corrected with a naviculocuneiform (NC) fusion. The NC joint has a curvature in the sagittal plane. Thus, preserving the shape of the joint is the key to permitting plantarflexion correction by rotating the midfoot along the debrided surfaces and to fix it. Intraoperatively, care must be also taken to not overcorrect the talocalcaneal angle in the horizontal plane during the ST fusion (eg, to exceed the external rotation of the talus and inadvertently put the midfoot in a supinated position). Such overcorrection can lead to lateral column overload with persistent lateral midfoot pain and discomfort. A contraindication for an isolated ST fusion may be a rupture of posterior tibial tendon because of the resultant loss of the internal rotation force at the TN joint. In these cases, a flexor digitorum longus tendon transfer is added to the procedure. LEVEL OF EVIDENCE: Level V, consensus, expert opinion.

Assessment of Posterior and Middle Facet Subluxation of the Subtalar Joint in Progressive Flatfoot Deformity.

BACKGROUND: Adult acquired flatfoot deformity (AAFD) is a complex 3-dimensional pathology characterized by peritalar subluxation (PTS) of the hindfoot. For many years, PTS was measured at the posterior facet of the subtalar joint. More recently, subluxation of the middle facet has been proposed as a more accurate and reliable marker of symptomatic AAFD, enabling earlier detection. The objective of this study was to compare the amount of subluxation between the medial and posterior facets in patients with AAFD. METHODS: In this institutional review board-approved retrospective comparative study, a total of 76 patients with AAFD (87 feet) who underwent standing weightbearing computed tomography (WBCT) as a standard baseline assessment of their foot deformity were analyzed. Two blinded fellowship-trained orthopedic foot and ankle surgeons with >10 years of experience measured subtalar joint subluxation (as a percentage of joint uncoverage) at the both posterior and middle facets. One of the readers also measured the foot and ankle offset (FAO). PTS measurements were performed at the sagittal midpoint of the articular facets using coronal plane WBCT images. Intra- and interobserver agreement was measured for PTS measurements using the intraclass correlation coefficient (ICC). The intermethod agreement between the posterior and middle facet subluxation was assessed using Spearman's correlation and bivariate analysis. Paired comparison of the measurements was performed using the Wilcoxon test. A multivariate analysis and a partition prediction model were used to assess influence of PTS measurements on FAO values. P values of <.05 were considered significant. RESULTS: ICCs for intra- and interobserver reliabilities were 0.97 and 0.93, respectively, for posterior and 0.99 and 0.97, respectively, for middle facet subluxation. The intermethod Spearman's correlation between subluxation of the posterior and middle facets was measured at 0.61. In a bivariate analysis, both measurements were found to be significantly and linearly correlated (P < .0001; R2 = 0.42). Measurements of middle facet subluxation were found to be significantly higher than those for posterior facet subluxation, with a median difference (using the Hodges-Lehman factor) of 17.7% (P < .001; 95% CI, 10.9%-23.6%). We also found that for every 1% increase in posterior facet subluxation there was a corresponding 1.6-fold increase in middle facet subluxation. Only middle facet subluxation measurements were found to significantly influence FAO calculations (P = .003). The partition prediction model demonstrated that a middle facet subluxation value of 43.8% represented an important threshold for increased FAO. CONCLUSION: This study is the first to compare WBCT measurements of subtalar joint subluxation at the posterior and middle facets as markers of PTS in patients with AAFD. We found a positive linear correlation between the measurements, with subluxation of the middle facet being significantly more pronounced than that of the posterior facet by an average of almost 18%. This suggests that middle facet subluxation may provide an earlier and more pronounced marker of progressive PTS in patients with AAFD. LEVEL OF EVIDENCE: Level III, retrospective comparative cohort study.

Palmar-divergent dislocation of the scaphoid and lunate treated using percutaneous pinning and pin-in-plaster: A case report.

Acute lunate and perilunate dislocations are not commonly observed injuries. In particular, palmar-divergent dislocation is a very rare injury with only a few cases reported in the literature. In this report, we describe the case of a 37-year-old patient with palmar-divergent dislocation of the scaphoid and lunate and discuss the mechanism of this type of injury. We also report a potential treatment for this pattern of palmar-divergent dislocation. The scapholunate and scaphocapitate joints were stabilized with K-wires and a modified pin-in-plaster fixation for 5 weeks after successful closed reduction. At the 1-year follow-up, magnetic resonance imaging showed no evidence of avascular necrosis of the scaphoid or lunate. However, radiographs showed mild dorsal intercalated segment instability deformity. The patient experienced no intermittent wrist pain or limitation in motion, with only 15% loss in grip strength. The Mayo wrist score was 90/100, and the patient resumed work as a craftsman. The carpal height ratio at the 4-year follow-up was 1.51 and 1.52 for the left and right wrists, respectively. In conclusion, we recommend this treatment method due to its benefits of being relatively simple, easy to perform, and having a relatively short operation time. Essentially, a good outcome was achieved using this method, including full range of motion and freedom from pain.

Using artificial neural networks to predict impingement and dislocation in total hip arthroplasty.

Dislocation after total hip arthroplasty (THA) remains a major issue and an important post-surgical complication. Impingement and subsequent dislocation are influenced by the design (head size) and position (anteversion and abduction angles) of the acetabulum and different movements of the patient, with external extension and internal flexion the most critical movements. The aim of this study is to develop a computational tool based on a three-dimensional (3D) parametric finite element (FE) model and an artificial neural network (ANN) to assist clinicians in identifying the optimal prosthesis design and position of the acetabular cup to reduce the probability of impingement and dislocation. A 3D parametric model of a THA was used. The model parameters were the femoral head size and the acetabulum abduction and anteversion angles. Simulations run with this parametric model were used to train an ANN, which predicts the range of movement (ROM) before impingement and dislocation. This study recreates different configurations and obtains absolute errors lower than 5.5° between the ROM obtained from the FE simulations and the ANN predictions. The ROM is also predicted for patients who had already suffered dislocation after THA, and the computational predictions confirm the patient's dislocations. Summarising, the combination of a 3D parametric FE model of a THA and an ANN is a useful computational tool to predict the ROM allowed for different designs of prosthesis heads.

Elbow Dislocation.

This article is a brief overview of the elbow dislocations focusing on updates in treatment and rehabilitation protocols. The fight between obtaining elbow stability without leading to long-term elbow stiffness has been a continued focus in field of sports medicine. This article highlights advances made to help treat the injuries appropriately and obtain optimal patient outcomes.

Finite elements analysis of the temporomandibular joint disc in patients with intra-articular disorders.

BACKGROUND: Intra-articular disorders (ID) or anterior and/or medial displacement of the temporomandibular joint disorder (TMJ) disc are the most common form of TMJ dysfunction (TMD). TMD causes changes in the friction coefficient during TMJ movement. Herein, we provided a three-dimensional (3D) finite-elements model (FEM) including the maxilla, disc, and mandible and evaluated the stress distribution with different friction coefficient. METHODS: Fourteen volunteers without TMD and 20 patients with MRI-diagnosed TMD were selected. CT and MRI data were collected to build the 3D FEA model of the mandible and TMJ disc. Stress distribution with different friction coefficient was measured. RESULT: In the normal model, stress distribution on the TMJ disc was 2.07 ± 0.17, 1.49 ± 0.14, and 1.41 ± 0.14 MPa with 0.001, 0.3, and 0.4 friction coefficient, respectively. In the TMD model, stress distribution was 3.87 ± 0.15, 7.23 ± 0.22, and 7.77 ± 0.19 MPa respectively. CONCLUSION: When the friction coefficient of the side with anterior displacement increased, stress on the disc, condyle and mandible of the opposite side increased. Simultaneously, stress values of the disc, condyle and mandible were higher than those of the normal lateral joint.

The Hip-Spine Relationship Simplified.

Much attention has recently been focused on the relationship between the hip and spine and its contribution to postoperative instability following total hip arthroplasty. However, the terminology can be confusing. Through an understanding of spinopelvic parameters, spinopelvic motion, and the interplay between the spine and pelvis, the surgeon can plan for and decrease the risk of instability after total hip arthroplasty. This review details spinopelvic parameters that predispose to instability and guides readers in understanding spinopelvic motion as it relates to THA instability.

Management of Finger Joint Dislocation and Fracture-Dislocations in Athletes.

Although finger joint dislocations are generally thought of as benign by many athletes and assumed to be a sprain, these injuries represent a spectrum that includes disabling fracture-dislocations. Failure to recognize certain dislocations or fracture-dislocations may result in permanent deformity and loss of motion. Simple dislocations are frequently amenable to early return to play with protection; however, more complex injuries may require specialized splinting or surgery. Delay in diagnosis of unstable proximal interphalangeal fracture-dislocations may require reconstruction or fusion. Early diagnosis and appropriate treatment are essential to ensure optimal functional results.

Lateral Meniscus Posterior Root Lesion Influences Anterior Tibial Subluxation of the Lateral Compartment in Extension After Anterior Cruciate Ligament Injury.

BACKGROUND: The lateral meniscus posterior root (LMPR) lesion further decreases dynamic knee stability after anterior cruciate ligament (ACL) injury owing to the loss of the "wedge effect" maintained by the posterior horn of the lateral meniscus. However, the effect of LMPR lesions on the static tibiofemoral relationship in extension after ACL injuries is not determined. PURPOSE: To (1) determine the effect of LMPR lesions on anterior tibial subluxation of the lateral compartment (ATSLC) in extension in patients with ACL injuries and to (2) identify the LMPR-related factors associated with excessive ATSLC in extension. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Between January 2015 and December 2017, 405 consecutive patients with diagnosed ACL injuries who underwent primary ACL reconstructions were retrospectively reviewed. Among them, 45 patients with combined ACL injuries and LMPR lesions (ACL+LMPR group) and 51 patients with isolated ACL injuries (ACL group) were identified. Values of ATSLC in extension were measured on preoperative supine magnetic resonance imaging and classified into high grade (≥6 mm) and low grade (<6 mm). The mean ATSLC in extension and the proportion of patients with high-grade ATSLC in extension were compared between the groups by univariate analysis. In the ACL+LMPR group, predictors of high-grade ATSLC in extension-including age, sex, body mass index, affected side, cause of injury, period from injury (<12 or ≥12 weeks), LMPR lesion pattern (radial tear or root avulsion), and meniscofemoral ligament integrity (intact or impaired)-were assessed by univariate analysis and multivariate logistic regression analysis. RESULTS: The mean ATSLC in extension in the ACL+LMPR group was significantly greater than that in the ACL group (5.6 mm vs 3.1 mm; P = .001). The proportion of patients with high-grade ATSLC in extension in the ACL+LMPR group was also significantly larger than that in the ACL group (44.4% vs 15.7%; P = .002). In addition, the root avulsion (instead of radial tear) (odds ratio, 28.750; 95% CI, 2.344-352.549; P = .009) and the period from injury ≥12 weeks (odds ratio, 17.095; 95% CI, 1.207-242.101; P = .036) were determined to be the 2 independent predictors of high-grade ATSLC in extension. However, age, sex, body mass index, affected side, cause of injury, and meniscofemoral ligament integrity were not. CONCLUSION: After ACL injuries, concomitant LMPR lesion further increased ATSLC in extension. Chronic LMPR avulsion was associated with high-grade ATSLC in extension.