Effects of preoperative sagittal spinal imbalance on pain after lateral lumbar interbody fusion.

Sagittal misalignment has been associated with negative quality of life (QOL). However, there is no report on whether differences in preoperative sagittal misalignment in patients with lumbar degenerative diseases affect postoperative results after lateral lumbar interbody fusion (LLIF). We investigated whether preoperative sagittal alignment influences the correction of alignment after surgery and whether the preoperative sagittal alignment affects the rating of low back pain, leg pain, and leg numbness. The subjects were 81 patients (48 male, 33 females, average age at surgery 70.2 years) who underwent anterior-posterior combined surgery with LLIF and percutaneous pedicle screws from May 2018 to July 2020. Cluster analysis was performed using the preoperative sagittal vertical axis (SVA) value, and patients were classified into two groups (group 1; n = 30, SVA = 129.0 ± 53.4 mm, group 2; n = 51, SVA = 30.8 ± 23.5 mm). Baseline demographics and treatment data were compared between groups. Sagittal and pelvic parameters and pain scores, such as low back pain, leg pain, and leg numbness, were also compared. Operative time, blood loss, and length of hospital stay did not differ significantly between groups. The changes (Δ) in SVA and lumbar lordosis (LL) for all patients from before to after surgery were not significant (ΔSVA; p = 0.218, ΔLL; p = 0.189, respectively). The SVA, LL, and PI - LL changed significantly after the surgery in group 1, but no marked improvement in sagittal imbalance was obtained after LLIF surgery. The improvement in each pain score from before to after the surgery did not differ significantly between groups. LLIF surgery has a limited chance of recovering sagittal imbalance. However, postoperative low back pain, leg pain, and leg numbness may be improved by LLIF surgery, regardless of the preoperative sagittal alignment.

The Influence of Postoperative Coronal Alignment on Tibial Migration After Total Knee Arthroplasty in Preoperative Varus and Valgus Knees: A Secondary Analysis of 10 Randomized Controlled Trials Using Radiostereometric Analysis.

BACKGROUND: Orthopaedic surgeons aim for mechanical alignment when performing total knee arthroplasty (TKA) as malalignment is associated with loosening. Loosening may be predicted by migration as measured with radiostereometric analysis (RSA), but previous RSA studies on postoperative alignment have shown contradictory results and have been limited to cemented implants and small numbers of patients. Therefore, we performed a secondary analysis of 10 previously published randomized controlled trials (RCTs) to compare migration between postoperative in-range and out-of-range cemented and uncemented TKA implants among patients with a preoperative varus or valgus knee. METHODS: All RCTs involving the use of RSA that had been conducted at 2 centers were included. Alignment was classified, with use of the hip-knee-ankle angle (HKA), as in-range (0° ± 3°) or out-of-range (<-3° or >3°). The fixation methods included cemented, uncemented-coated, and uncemented-uncoated. Migration was measured at 3, 12, and 24 months. A linear mixed model was used, with adjustment for fixation method and clustering of patients within centers. RESULTS: Of 476 TKA implants that had been out-of-range preoperatively, 290 were in-range postoperatively and 186 were out-of-range in either varus (n = 143) or valgus (n = 43) postoperatively. The mean migration at 3, 12, and 24 months was 0.73 mm (95% confidence interval [CI], 0.66 to 0.79 mm), 0.92 mm (95% CI, 0.85 to 1.00 mm), and 0.97 mm (95% CI, 0.90 to 1.05 mm), respectively, for the in-range group and 0.80 mm (95% CI, 0.72 to 0.87 mm), 0.98 (95% CI, 0.90 to 1.07 mm), and 1.04 mm (95% CI, 0.95 to 1.13 mm), respectively, for the out-of-range group (p = 0.07). The fixation method significantly influenced migration, with uncemented-uncoated implants migrating more than cemented and uncemented-coated implants (p < 0.001). CONCLUSIONS: Postoperative alignment did not influence migration of TKAs in the first 2 postoperative years in patients with preoperative varus or valgus alignment of the knee. However, the fixation method significantly influenced migration, with uncemented-uncoated implants showing the greatest migration. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Transiency of postoperative cervical kyphosis seen after surgical correction of sagittal malalignment in adult spinal deformity patients.

OBJECTIVE: In this study, we evaluated factors affecting changes in cervical lordosis after deformity correction and during follow-up period in adult spinal deformity (ASD) patients with severe sagittal imbalance. METHODS: Seventy-nine patients, with an average age of 71.6 years, who underwent long-segment fixation from T10 to S1 with sacropelvic fixation were included. We performed a comparative analysis of the radiographic parameters after surgery (Post) and at the last follow-up (Last). We calculated the Pearson's correlation coefficient and performed multilinear regression analysis to predict independent parameters for Post and Last cervical lordosis (CL), T1 slope (T1S), and thoracic kyphosis (TK). RESULTS: Hyperlordotic changes of -23.3° in CL before surgery was reduced to -7° after surgery, and Last CL had increased to -15.3°. T1S was reduced from 27° before surgery to 14.4° after surgery and had increased to 18.8° at the last follow-up. Through multilinear regression analysis, we found that Post CL and T1S were more significantly affected by the amount of LL correction (p = .045 and .049). The effect of Last T1S was significantly associated with the Last CL; the effect of Last TK, with the Last T1S; and the effect of Post PI-LL, with the Last TK (p < .05). CONCLUSION: The postoperative kyphotic change in CL in ASD patients with preoperative cervical hyperlordosis is not permanent and is affected by drastic LL correction and SVA restoration. To achieve spinopelvic harmony proportional to the difference in LL relative to PI, TK becomes modified over time to increase T1S and CL, in an effort to achieve optimal spine curvature.

Coronal Plane Alignment of the Knee (CPAK) classification.

AIMS: A comprehensive classification for coronal lower limb alignment with predictive capabilities for knee balance would be beneficial in total knee arthroplasty (TKA). This paper describes the Coronal Plane Alignment of the Knee (CPAK) classification and examines its utility in preoperative soft tissue balance prediction, comparing kinematic alignment (KA) to mechanical alignment (MA). METHODS: A radiological analysis of 500 healthy and 500 osteoarthritic (OA) knees was used to assess the applicability of the CPAK classification. CPAK comprises nine phenotypes based on the arithmetic HKA (aHKA) that estimates constitutional limb alignment and joint line obliquity (JLO). Intraoperative balance was compared within each phenotype in a cohort of 138 computer-assisted TKAs randomized to KA or MA. Primary outcomes included descriptive analyses of healthy and OA groups per CPAK type, and comparison of balance at 10° of flexion within each type. Secondary outcomes assessed balance at 45° and 90° and bone recuts required to achieve final knee balance within each CPAK type. RESULTS: There was similar frequency distribution between healthy and arthritic groups across all CPAK types. The most common categories were Type II (39.2% healthy vs 32.2% OA), Type I (26.4% healthy vs 19.4% OA) and Type V (15.4% healthy vs 14.6% OA). CPAK Types VII, VIII, and IX were rare in both populations. Across all CPAK types, a greater proportion of KA TKAs achieved optimal balance compared to MA. This effect was largest, and statistically significant, in CPAK Types I (100% KA vs 15% MA; p < 0.001), Type II (78% KA vs 46% MA; p = 0.018). and Type IV (89% KA vs 0% MA; p < 0.001). CONCLUSION: CPAK is a pragmatic, comprehensive classification for coronal knee alignment, based on constitutional alignment and JLO, that can be used in healthy and arthritic knees. CPAK identifies which knee phenotypes may benefit most from KA when optimization of soft tissue balance is prioritized. Further, it will allow for consistency of reporting in future studies. Cite this article: Bone Joint J 2021;103-B(2):329-337.

Lower Limb Malrotation Is Regularly Present in Long-Leg Radiographs Resulting in Significant Measurement Errors.

Weight-bearing long-leg radiographs are commonly used in orthopaedic surgery. Measured parameters, however, change when radiographs are conducted in different rotational positions of the leg. It was hypothesized that rotational errors are regularly present in long-leg radiographs resulting in wrong measurements. In 100 consecutive long-leg radiographs conducted according to the method of Paley, rotation was assessed by fibular overlap. Angular parameters in radiographs (mechanical lateral proximal femoral angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), angle between the anatomical and mechanical femoral axis (AMA), mechanical medial proximal tibia angle (mMPTA), mechanical lateral distal tibial angle (mLDTA), and the mechanical femoral and tibial axis (mFA-mTA) were measured and deviations related to malrotation calculated. An average internal rotation of 8 degrees was found in lower limbs showing a range between 29 degrees of internal and 22 degrees of external rotation. As a result, mean differences before and after rotational correction for measured parameters (mLPFA, mLDFA, AMA, mMPTA, mLDTA, mFA-mTA) ranged between 0.4 and 1.7 degrees (-2.1; 5.6 95% confidence interval [CI]). In conclusion, malrotation of lower limbs is regularly present in long-leg radiographs. As all measured parameters are influenced by malrotation, correct lower limb rotation needs to be verified.

Impact of cervical sagittal parameters on axial neck pain in patients with cervical kyphosis.

BACKGROUND: Cervical sagittal alignment (CSA) is closely related with cervical disk degeneration and impacts the spinal function, especially in the setting of cervical kyphosis (CK). In this study, we evaluated the influence of cervical sagittal parameters on the development of axial neck pain (ANP) in patients with CK. METHODS: Data pertaining to 263 patients with CK who visited the outpatient department of our hospital between January 2012 and December 2018 were retrospective analyzed. The most common symptoms of ANP were neck pain, stiffness, or dullness. Visual analog scale (VAS) was used to evaluate ANP. The following radiographic parameters were evaluated: CK types, C2-7 sagittal vertical axis (SVA), thoracic inlet angle (TIA), T1 slope, neck tilt (NT), cranial tilt, and cervical tilt. Sagittal alignment of CK was classified into 2 types: global and regional type. Multivariate logistic regression analysis was performed to identify risk factors for ANP. RESULTS: Patients who complained of ANP were categorized as ANP group (VAS score ≥ 3; n = 92), while those without ANP were categorized as non-ANP group (VAS score < 3; n = 171). There was no significant between-group difference with respect to age (P = 0.196), gender (P = 0.516), TIA (P = 0.139), NT (P = 0.676), CK type (P = 0.533), cranial tilt (P = 0.332), cervical tilt (P = 0.585), or cervical disk degeneration (P = 0.695). The T1 slope and C2-7 SVA in the ANP group were significantly greater than that in the non-ANP group (P < 0.05). On multivariate logistic regression, C2-7 SVA [ odds ratio (OR) 2.318, 95% confidence interval 1.373-4.651, P = 0.003) and T1 slope (OR 2.563, 95% CI 1.186-4.669, P = 0.028) were identified as risk factors for ANP. CONCLUSIONS: Our findings suggest a significant effect of cervical sagittal parameters on the occurrence of ANP in patients with CK. Greater T1 slope and larger C2-7 SVA may lead to the development of neck pain.

Cartilage Injury in the Knee: Assessment and Treatment Options.

Cartilage injuries in the knee are common and can occur in isolation or in combination with limb malalignment, meniscus, ligament, and bone deficiencies. Each of these problems must be addressed to achieve a successful outcome for any cartilage restoration procedure. If nonsurgical management fails, surgical treatment is largely based on the size and location of the cartilage defect. Preservation of the patient's native cartilage is preferred if an osteochondral fragment can be salvaged. Chondroplasty and osteochondral autograft transfer are typically used to treat small (<2 cm) cartilage defects. Microfracture has not been shown to be superior to chondroplasty alone and has potential adverse effects, including cyst and intralesional osteophyte formation. Osteochondral allograft transfer and matrix-induced autologous chondrocyte implantation are often used for larger cartilage defects. Particulated juvenile allograft cartilage is another treatment option for cartilage lesions that has good to excellent short-term results but long-term outcomes are lacking.

What is the impact of patellofemoral joint degeneration and malalignment on patient-reported outcomes after lateral unicompartmental knee arthroplasty?

AIMS: It remains controversial whether patellofemoral joint pathology is a contraindication to lateral unicompartmental knee arthroplasty (UKA). This study aimed to evaluate the effect of preoperative radiological degenerative changes and alignment on patient-reported outcome scores (PROMs) after lateral UKA. Secondarily, the influence of lateral UKA on the alignment of the patellofemoral joint was studied. METHODS: A consecutive series of patients who underwent robotic arm-assisted fixed-bearing lateral UKA with at least two-year follow-up were retrospectively reviewed. Radiological evaluation was conducted to obtain a Kellgren Lawrence (KL) grade, an Altman score, and alignment measurements for each knee. Postoperative PROMs were assessed using the Kujala (Anterior Knee Pain Scale) score, Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS JR), and satisfaction levels. RESULTS: A total of 140 knees (130 patients) were identified for analysis. At mean 4.1 years (2.0 to 8.5) follow-up, good to excellent Kujala scores were reported. The presence of mild to moderate preoperative patellofemoral joint osteoarthritis had no impact on these scores (KL grade 0 vs 1 to 3, p = 0.203; grade 0 to 1 vs 2 to 3, p = 0.674). Comparable scores were reported by patients with osteoarthritis (Altman score of ≥ 2) evident on either the medial or lateral patellofemoral joint facet (medial, p = 0.600 and lateral, p = 0.950). Patients with abnormal patellar congruence and tilt angles (≥ 17° and ≥ 14°, respectively) reported good to excellent Kujala scores. Furthermore, lateral UKA resulted in improvements to patellofemoral alignment. CONCLUSION: This is the first study demonstrating that mild to moderate preoperative radiological degenerative changes and malalignment of the patellofemoral joint are not associated with poor patient-reported outcomes at mid-term follow-up after lateral fixed-bearing UKA. Our data suggest that this may be explained by realignment of the patella and thereby redistribution of loads across the patellofemoral joint. Cite this article: Bone Joint J 2020;102-B(6):727-735.

Reconstruction of Severe Ankle and Pilon Fracture Malunions.

Malunion of ankle and pilon fractures has significant detrimental effect on function and development of post-trauma osteoarthritis. Unfortunately, the incidence of malunion has been reported to be increasing. It is important to assess the ankle for congruency, because this determines the level where correction will occur. A plethora of techniques are available, with low-level evidence supporting each, and therefore it is important that the treating surgeon is fully prepared and comfortable in the techniques they are to use. Supplementary procedures are common and should be expected. This article provides a review of current methods of treatment and their outcomes.

Effects of malalignment and disease activity on osteophyte formation in knees of rheumatoid arthritis patients.

PURPOSE: Rheumatoid arthritis (RA) patients with secondary osteoarthritis (OA) in a knee joint following a total knee arthroplasty (TKA) procedure have been increasing. Here, we investigated osteophyte formation in knee joints of RA patients and associated factors. METHODS: We retrospectively examined findings of 35 knees in 30 RA patients (26 females, 4 males; mean age: 63.0 years; median disease duration: 15 years) who underwent TKA, including preoperative anteroposterior view radiographs of the knee joint. Using the ImageJ software package, osteophyte size in the medial femur (MF), medial tibia (MT), lateral femur (LF), and lateral tibia (LT) regions was also determined. RESULTS: The mean femorotibial angle was 179°, while Larsen grade was 2 in 1, 3 in 12, 4 in 18, and 5 in 2 patients. Osteophyte sizes in the MF, MT, LF, and LT regions were 37.2, 17.0, 27.2, and 4.57 mm2, respectively, and significantly greater in the medial compartment (MC; MF+MT) than the lateral compartment (LC; LF+LT) (p < 0.001). In varus cases, osteophyte size in the MC was significantly larger than normal and valgus cases (p = 0.0016). Furthermore, osteophyte size in the MC was negatively correlated with the inflammatory markers C-reactive protein (r = -0.492, p = 0.0027) and erythrocyte sedimentation rate (r = -0.529, p = 0.0016), whereas that in the LC was negatively correlated with disease activity (r = -0.589, p = 0.0023). CONCLUSION: Our results suggest that alignment and disease activity influence osteophyte formation in RA patients, with secondary OA a more prominent symptom in RA patients with controlled inflammation.

Ulnar Abutment Syndrome in the Athlete.

Ulnar abutment (ulnocarpal impaction) syndrome may be a source of ulnar-sided wrist pain in the athlete. This condition results from excessive load transfer across the triangular fibrocartilage complex and ulnocarpal joints with characteristic degenerative changes. It frequently occurs in patients with either static or dynamic ulnar positive variance. Treatment is tailored to the athlete and their sporting demands. Surgical treatment focuses on addressing ulnar variance to unload the ulnocarpal joint, with multiple surgical options, including the metaphyseal closing wedge osteotomy achieving this goal. This review focuses on the presentation, biomechanics, and treatment options for ulnar abutment syndrome in the athlete.

PROMIS is superior to established outcome measures in capturing disability resulting from sagittal malalignment in patients with back pain.

INTRODUCTION: Patient reported outcomes measurement information system (PROMIS) is a quality of life metric that has gained increased popularity due to computer adaptive testing. Previous studies have shown that PROMIS correlates with Oswestry Disability Index (ODI) in patients with back pain and takes significantly less time to complete. However, the ability of PROMIS to capture disability from spinal malalignment relative to established metrics is unknown. The aim of the present study is to validate the correlation between ODI and PROMIS in patients with back pain, analyze correlations of PROMIS and legacy metrics to sagittal alignment, and identify major drivers of PROMIS scores and ODI in patients with back pain. METHODS: A retrospective review was conducted of a prospectively collected outcome measures database (PROMIS, ODI, VAS Back, VAS Leg, VAS Neck, and VAS Arm) of spine patients > 18 years. Inclusion criteria for the present study was a chief complaint of back pain and full length weight bearing X-rays within 30 days of health related quality of life (HRQL) completion. Demographic information, radiographic alignment, psychiatric diagnoses, and comorbidities were recorded. PROMIS metrics were correlated to legacy metrics (ODI and VAS). Next, outcome metrics were correlated with sagittal alignment variables T1 Pelvic Angle (TPA), SVA, PT, and PI-LL. Patients were grouped based on the presence of spinal deformity (defined radiographically as any one of SVA > 4 cm, PI-LL > 10°, PT > 20°) and mean HRQL scores were investigated for the adult spinal deformity (ASD) and non-ASD groups. Finally, drivers of PROMIS PF scores and ODI scores were determined using multiple stepwise regression. RESULTS: 150 patients met inclusion criteria including 60 patients with ASD and 90 patients without. For the whole cohort, PROMIS PF correlated with ODI (r = - 0.651, p < 0.001), VAS Back (r = - 0.260, p = 0.014) and Charleson Comorbidity Index (r = - 0.336, p < 0.001). PROMIS PF had higher correlations than ODI for each sagittal alignment parameter tested, including TPA, SVA, PT, and PI-LL. When patients with ASD were compared to non-ASD patients, the PROMIS score was different between the groups but the ODI and VAS scores were not. Finally, stepwise linear regression showed that SVA, PI-LL, and VAS Leg were significant drivers of PROMIS PF (r2 = 0.406, p < 0.001). VAS Leg and VAS Back were significant contributors to ODI (r2 = 0.376, p < 0.001). CONCLUSIONS: In a cohort of 150 patients with back pain, PROMIS correlated strongly with legacy outcome metrics, including VAS and ODI. PROMIS PF correlated more strongly with sagittal malalignment than ODI. Additionally, patients with spinal deformity had significantly worse PROMIS PF scores but similar ODI scores as patients without ASD. Finally, sagittal alignment was found to be a significant driver of PROMIS PF scores but not ODI scores. PROMIS PF should be utilized as a disability assessment tool in patients with spinal deformity due to ease of use, strong correlations with legacy metrics, and ability to capture disability resulting from sagittal alignment.

The Outcomes of Isolated Distal Realignment Procedures in Patellofemoral Instability: A Systematic Review and Meta-analysis.

Distal realignment procedures are now commonly performed routinely with proximal realignment procedures. Despite so, only a limited number of publications exist that have looked into the efficacy of isolated distal realignment procedures, and whether there is indeed a need for routine proximal realignment procedures to be added to the distal realignment procedures. The current systematic review and meta-analysis aims to evaluate the outcomes of isolated distal realignment procedures in the management of patellofemoral instability. The review was conducted using the preferred reporting items for systematic reviews and meta-analyses (PRSIMA) guidelines. All studies that reported the outcomes of isolated distal realignment procedures for patellofemoral instability were included. A total of six publications were included, with 347 knees. All studies consistently reported a decrease in the rates of patellofemoral instability or maltracking (odds ratio [OR]: < 0.01; 95% confidence interval [CI]: < 0.01-0.01) and an increase in the odds of having a good outcome (OR: 0.01; 95% CI: < 0.01-0.02) after distal realignment procedures. A total of 24 out of 306 patients (7.8%) had postoperative instability or maltracking, and a total of 220 out of 303 patients (72.6%) were rated to have good or excellent outcomes postoperatively. Isolated distal realignment procedures can lead to good outcomes when used in the management of patellofemoral instability. These include a significantly decreased rate of patellofemoral instability or maltracking and a significantly increased number of patients with excellent or good outcomes postoperatively. Comparisons between patients with and without additional proximal realignment procedures suggest that additional proximal realignment procedures do not definitely improve the outcomes of distal realignment procedures and, therefore, should not be routinely performed in all patients undergoing distal realignment procedures. The Level of Evidence for this study is IV.

Is There a Relationship between Patellofemoral Alignment and Osgood-Schlatter Disease? A Case-Control Study.

This study was aimed to investigate the role of anatomic variations in patellofemoral alignment in patients with or without Osgood-Schlatter disease (OSD) and to determine the potential anatomic risk factors that may play role in the etiology. This prospective observational case-control study was conducted on two groups of adolescent patients. Group 1 comprised patients who were diagnosed as having OSD and group 2 consisted of an equal number of age-matched patients who presented to the outpatient clinic with traumatic knee injury and underwent knee radiographic examination but without a diagnosis of OSD. Age, height, weight, body mass index (BMI), dominant side, and level of sporting activity were recorded. Quadriceps (Q) angles were measured using a long-arm goniometer with patients lying in the supine position with their knees in full extension and contracting the Q muscles. On anteroposterior, lateral knee, and tangential patella (Merchant and Laurin views) radiographs, the following measurements were performed: Insall-Salvati (IS), Caton-Deschamps (CD), and Blackburne-Peel (BP) indexes, congruence angles, lateral patellofemoral angles, sulcus angles, and patella type according to Grelsamer's morphology classification. Both groups were similar in respect of age (p = 0.160), sex (p = 0.311), height (p = 0.326), weight (p = 0.596), BMI (p = 0.153), and dominancy (p = 0.500). The rate of patients engaged in sports activities was significantly greater in the OSD group (p = 0.003). No significant difference was determined between the groups in respect to IS index, CD index, BP index, sulcus angle, lateral patellofemoral angle, and congruence angle (p-values: 0.358, 0.995, 0.912, 0.802, 1.000, and 0.907, respectively). The mean Q angle was measured as 15.6 ± 2.2 degrees in the OSD group and 14.3 ± 2.5 degrees in the control group (p = 0.014). Despite the difference being statistically significant, it was clinically insignificant because the difference was only 1.3 degrees. The principle etiologic factor seems to be increased physical activity rather than subtle variations is patellofemoral anatomy and alignment of extensor mechanism.

Role of Alignment and Osteotomy in Meniscal Injuries.

Meniscal injuries are common in patients with varus or valgus malalignment, but consensus is lacking as to when surgery should address the meniscal injury only and when it should be combined with an osteotomy. Several factors need to be evaluated to provide the most appropriate treatment in each case. Here we highlight the most relevant literature on the subject and suggest a rationale for surgical treatment.

Unusual form of the distal bone defect of ulna with neurofibromatosis type 1: A case report.

RATIONALE: Bone malformation occurs in 10% to 25% neurofibromatosis type 1 (NF-1) patients, and the manifestations are scoliosis, congenital arch and pseudo-joint formation, bone cyst, and pathologic fracture. However, a large segmental defect without obvious signs of bone destruction has rarely been reported. PATIENT CONCERNS: A 4.5-year-old male presented with a 4-year history of shortening of the right upper limb and radial head dislocation. The X-ray indicated a lack of the distal part of the right ulna and radial head dislocation. DIAGNOSIS: The X-ray showed obvious bone resorption at the right ulna distal, proximal stubble, and distal part of the epiphyseal residue, which was 4.3 mm shorter after 14 months. The patient was finally diagnosed with NF-1 according to the pathologic examination. INTERVENTIONS: The treatment included tumor resection, ulnar osteotomy, and fixation by an Ilizarov frame. OUTCOMES: The Ilizarov frame was removed after 2.7 months of surgery. The radial head was successfully repositioned, and the elbow joint function was significantly improved. No recurrence of the deformity was noted until now. LESSONS: Osteolysis (defect without bone destruction) is an extremely rare symptom in patients with NF1. Therefore, it is essential to make the right diagnosis by comprehensive and careful physical examination.

The Natural History of Lower Extremity Malalignment.

BACKGROUND: Lower extremity malalignment is a common problem presented to pediatric orthopaedists. Risk for early arthritis is often a concern among parents seeking advice and treatment. We seek to review previous research with regard to the natural history of malalignment. METHODS: A search of available literature on PubMed was constructed to capture articles covering the natural history of malalignment, secondary to childhood fracture as well as congenital and acquired pediatric deformity. In order to remain strictly relevant to pediatrics, articles reviewing deformities acquired in adulthood were not referenced. Biomechanical data and animal studies were included when deemed appropriate. RESULTS: High-quality data with regard to long-term risk of arthritis due to malalignment is lacking. Through a combination of biomechanical data, animal models, and a small body of longitudinal clinical data, it is clear that some patients with malalignment progress to early arthritic change. Unfortunately, detailed risk factors of who is at high risk versus low risk remains difficult to determine. CONCLUSIONS: Treatment of minor lower extremity malalignment is not supported by the current orthopaedic literature. Treatment plans should focus on the presence of symptoms, and in asymptomatic but severe cases. Even in more severe cases, strong evidence to support prophylactic realignment is not available. Evidence to suggest that preventative realignment is superior to intervention at the time of symptom onset does not exist.

Risk factor heterogeneity for medial and lateral compartment knee osteoarthritis: analysis of two prospective cohorts.

OBJECTIVE: To evaluate the etiologic heterogeneity between medial and lateral tibiofemoral radiographic osteoarthritis (ROA). METHODS: Knees without medial or lateral tibiofemoral ROA at baseline were followed for 60-month in Multicenter Osteoarthritis Study (MOST) and for 48-month in Osteoarthritis Initiative (OAI). We examined the relation of previously reported risk factors to incident medial and lateral tibiofemoral ROA separately and determined the etiology heterogeneity with a ratio of rate ratios (RRs) (i.e., the RR for medial tibiofemoral ROA divided by the RR for lateral tibiofemoral ROA) using a duplication method for Cox proportional hazard regression. RESULTS: Of 2,016 participants in MOST, 436 and 162 knees developed medial or lateral tibiofemoral ROA, respectively. Obesity and varus malalignment were 95% and 466% more strongly associated with incident medial tibiofemoral ROA than with lateral tibiofemoral ROA, respectively (ratios of RRs, 1.95 [95% confidence interval (CI):1.05-3.62] and 5.66 [95% CI:3.20-10.0]). In contrast, the associations of female sex and valgus malalignment with incident medial tibiofemoral ROA were weaker or in an opposite direction compared with lateral tibiofemoral Osteoarthritis (OA) (ratios of RRs, 0.40 [95% CI:0.26-0.63] and 0.20 [95% CI:0.12-0.34], respectively). Older age tended to show a weaker association with incident medial tibiofemoral ROA than with incident lateral tibiofemoral ROA. No heterogeneity was observed for the relation of race, knee injury, or contralateral knee ROA. These findings were closely replicated in OAI. CONCLUSION: Risk factor profiles for medial and lateral tibiofemoral ROA are different. These results can provide a framework for the development of targeted prevention and potential treatment strategies for specific knee OA subtypes.

Do femoral fractures in adult patients with osteogenesis imperfecta imitate atypical femoral fractures? A case series.

Atypical femoral fractures (AFFs) are low-energy femoral fractures with characteristic radiological features and a suspected relation to treatment with bisphosphonate (BP) or denosumab. In osteogenesis imperfecta (OI), BP is currently the drug of choice when medical treatment is indicated. Due to bone deformities, the radiologic appearance of femoral fractures may be different in patients with OI and patients with osteoporosis. We investigated the prevalence and appearance of femoral fractures in a cohort of adult patients with confirmed OI (55 patients, age range 19-69 years, 26 women (47%) and 35 patients (64%) had received BP treatment), who attended the outpatient clinic at Aarhus University Hospital. The fractures were evaluated according to major and minor AFF criteria. In our OI cohort, we found that eight out of 55 patients had suffered a femoral fracture in adult year: five women and three men, aged 25 to 54 years. One patient had OI type I, two had OI type III, four had OI type IV, and one had OI type V. All fractures were associated with no or minimal trauma. Four patients had fractures that fulfilled the criteria of AFFs. Two of the four patients had received long-term BP treatment prior to the fracture and three patients had severe deformities of the femur. Femoral fractures in OI imitate AFFs. This suggests that bone deformity, collagen deficiencies, and alterations in mineralization of bone may cause femoral fractures that imitate AFFs even in the absence of antiresorptive treatment. Bone deformities should be monitored as part of the management of adult patients with OI. Continuous dull or aching pain in the groin or thigh should lead to radiographic examination. The radiologic appearance of femoral fractures may be different in patients with osteogenesis imperfecta (OI) and patients with osteoporosis, thus imitate atypical femoral fractures (AFF). We found that bone deformity, collagen deficiencies, and alterations in bone mineralization may cause femoral fractures that imitate AFFs even in the absence of antiresorptive treatment.

Evaluation of Femoral-Tibial Flexion Gap in Total Knee Arthroplasty with Everted or Lateralized Patella.

Intraoperative patellar position (eversion, lateralization, or in situ) influences the ligamentous balancing in knee flexion and thereby the correct positioning of the femoral component during total knee arthroplasty. The correct ligament balancing is crucial when, as in our experience, prostheses with medial pivot design are used. It was shown that the flexion gap in the normal knee is not rectangular and that the lateral compartment is significantly slacker than the medial. Therefore, to obtain a correct kinematics of a medial pivot anatomical prosthesis, it is essential to recreate an anatomical flexion gap slacker in the lateral compartment. We conducted a prospective study on a consecutive series of 87 total knee prostheses. The objective of this study is to evaluate the femoral external rotation angle in each patient with everted patella as well as with pure subluxated patella. The purpose of this study is to offer guidance about the optimal femoral rotation angle to achieve best outcomes of a knee replacement. The evaluation was done using an instrument developed by Medacta International (Switzerland) with our direct collaboration (Tensor, Medacta, Switzerland) and standardizing the basic conditions of each patient (knee 90 degrees flexed, medial transquadricipital surgical access, lateral displacement of the patella, tourniquet inflated at 250 mm Hg, spinal anesthesia). Each group was subdivided into subgroups according to gender, preoperative varus or valgus deformity, and patellar height. Our study advises against evaluating the flexion gap with everted patella due to high risk of underestimation of the lateral compartment laxity (differences up to + 3 degrees with pure subluxated patella compared with everted patella).