Posterior Distal Femoral Angle Research Articles

Surgical Technique and Preliminary Outcomes of Double-Level Osteotomy for Valgus Deformity.

Data are limited regarding the surgical technique or outcomes of double-level osteotomy (DLO) combining medial closing-wedge distal femoral osteotomy and medial closing-wedge high tibial osteotomy in patients with moderate-to-severe valgus deformity. To describe the surgical technique and assess the short-term outcomes and surgical accuracy of DLO in patients with a moderate or severe valgus deformity. It was hypothesized that this technique would result in good clinical outcomes with precise deformity correction. Case series; Level of evidence, 4. Eight patients (mean age, 44.2 ± 10.9 years) with a moderate or severe valgus knee treated with DLO (9 knees; mechanical tibiofemoral angle [mTFA], 10.3°± 3.5°) were included. The mean follow-up was 25.1 ± 11.1 months. Preoperative to postoperative changes in radiographic parameters (mTFA, mechanical lateral distal femoral angle, mechanical medial proximal tibial angle, joint line convergence angle) and clinical scores (Hospital for Special Surgery score, Oxford Knee Score, Lysholm score) were assessed. Surgical accuracy was calculated by subtracting the achieved postoperative correction from the preoperatively planned targeted correction. The mTFA changed significantly from 10.3°± 3.5° preoperatively to -1.8°± 3.4° postoperatively (P < .001); the mechanical lateral distal femoral angle and mechanical medial proximal tibial angle changed significantly by 5.1°± 2.7° and 5.9°± 2.2°, respectively (P < .001 for both); and the posterior distal femoral angle decreased significantly from 85.9°± 3.1° to 84.2°± 2.4° (P < .01). There was no significant difference between pre- and postoperative joint line convergence angles (3.3°± 2.3° to 2.6°± 2.1°). The accuracy of the correction was high: the mTFA achieved postoperatively differed from the mTFA planned preoperatively by a mean of 2.7°± 1.9° (range, 0.6°-6.6°). Significant pre- to postoperative improvement was seen for all outcome scores (Hospital for Special Surgery, from 67 ± 11 to 93 ± 4; Oxford Knee Score, from 29 ± 7 to 43 ± 3; Lysholm, from 41 ± 24 to 89 ± 8; P < .001 for all). High surgical accuracy was achieved, and patients who underwent varus DLO for valgus knees showed improved knee function at short-term follow-up. Varus DLO can be a surgical option to restore the optimal alignment and joint line obliquity in patients with moderate or severe valgus malalignment.

Retrograde intramedullary nail fixation with oblique fixed angle screws versus locking plates in periprosthetic supracondylar fractures after total knee arthroplasty.

Common surgical procedures in the treatment of periprosthetic distal femur fractures (PPFF) include osteosynthesis with fixed angle locking plates (LP) and retrograde intramedullary nails (RIN). This study aimed to compare LPs to RINs with oblique fixed angle screws in terms of complications, radiographic results and functional outcome. 63 PPFF in 59 patients who underwent treatment in between 2009 and 2020 were included and retrospectively reviewed. The anatomic lateral and posterior distal femoral angle (aLDFA and aPDFA) were measured on post-surgery radiographs. The Fracture Mobility Score (FMS) pre- and post-surgery, information about perceived instability in the operated leg and the level of pain were obtained via a questionnaire and previous follow-up (FU) examinations in 30 patients (32 fractures). The collective (median age: 78years) included 22 fractures treated with a RIN and 41 fractures fixed with a LP. There was no difference in the occurrence of complications (median FU: 21.5months) however the rate of implant failures requiring an implant replacement was higher in fractures treated with a LP (p = 0.043). The aPDFA was greater in fractures treated with a RIN (p = 0.04). The functional outcome was comparable between both groups (median FU: 24.5months) with a lower outcome in the post-surgery FMS (p = < 0.001). Fractures treated with RIN resulted in an increased recurvation of the femur however the rate of complications and the functional outcome were comparable between the groups. The need for implant replacements following complications was higher in the LP group.

Novel classification system for periprosthetic distal femoral fractures: a consideration for comminution.

Comminution is an aspect of periprosthetic distal femoral fractures (PDFFs) that can influence postoperative outcomes and treatment selection, but is not included in current classification systems. We propose a new classification system for PDFFs based on comminution and cortical reads. This study aims to prove its reliability and efficacy to predict fracture severity and guide treatment. A retrospective chart review of patients treated with single or dual locking plates for PDFFs was performed. Two fellowship-trained orthopedic joint reconstruction specialists used available imaging to classify each PDFF as either type 1 (minimal or no comminution allowing for reconstruction of medial and lateral cortices), type 2 (comminution reasonably allowing for reconstruction of either medial or lateral cortex), and type 3 (extensive comminution not allowing reasonable reconstruction of medial or lateral cortex). Each PDFF was then analyzed for radiographic outcomes including lateral distal femoral angle (LDFA) and the posterior distal femoral angle (PDFA). Interobserver reliability assessed by Cohen's Kappa statistic was 0.707, and average intraobserver reliability was 0.843, showing substantial reliability. Type 3 PDFFs had greater varus deformity than type 1 (p = 0.0457) or 2 (0.0198). The proposed classification system accounts for comminution, demonstrates strong interobserver and intraobserver reliability, and can be used to guide treatment in regard to single versus dual plating. Retrospective comparative study, Level IV.

Sagittal Plane Assessment in Deformity Correction Planning: The Sagittal Joint Line Angle.

Evaluate the validity of a recent approach to calculate the knee flexion or extension contracture contributing to the overall sagittal deformity using the sagittal mechanical axis angle (SMAA) for the overall alignment assessment and sagittal joint line angle (SJLA) for soft tissue contribution. The methods of evaluating these angles and their clinical applications are discussed. In total, 107 normal limbs met the criteria and were divided into two groups: skeletally mature and immature. Sagittal alignment was evaluated using the Bone Ninja iPad application, and the posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA), SMAA and SJLA were recorded. In skeletally immature patients, mean SJLA was 13.46° [standard deviation (SD), 4.55°], and in mature patients, it was 16.91° (SD, 2.948°). The PDFA and PPTA were consistent with previously published measurements. The SJLA method is a practical way to quantify the soft tissue contribution and degree of contracture. It can also be used for monitoring deterioration or improvement of knee range of motion during lengthening or physical therapy. All patients in this study presented to our clinic with symptoms on the contralateral side. This, in addition to the retrospective nature, was a limitation in our study.We recommend a validity study to compare our SJLA method to the classic anterior cortical line angle (ACL) method in addition to an inter-observer and intra-observer reliability study for the SJLA. We also recommend a study on completely normal asymptomatic subjects to better standardise the angle measurements in skeletally immature patients at different ages. Abalkhail TB, McClure PK. Sagittal Plane Assessment in Deformity Correction Planning: The Sagittal Joint Line Angle. Strategies Trauma Limb Reconstr 2022;17(3):159-164.

Outcomes of surgical management of closed periprosthetic distal femur fractures above total knee arthroplasties: A case series

Periprosthetic distal femur fractures present difficult treatment challenges and are expected to become more prevalent as the number of total knee arthroplasties (TKAs) continues to rise. The purpose of this study is to determine the functional outcomes and rate of re-operation following surgical treatment of closed distal femoral periprosthetic fractures above a TKA. We performed a retrospective review of 56 patients(45 females) who underwent surgical management of distal femur fractures (AO/OTA 33) above an ipsilateral TKA with a mean follow-up of 21 months (range, 12-78 months). Forty-three (77%) patients were treated with a lateral plate and screw construct, and 13 (23%) patients were treated with a retrograde intramedullary nail. There were 2 (4%) deep infections at a mean of 6 months (range, 5-7 months) post-operatively. At final follow-up, TKA components were retained in 53 (93%) patients, demonstrating a survivorship free of component revision following fracture treatment of 93% at 6.5 years. Survivorship free of any re-operation following fracture treatment was 86% at 6.5 years. Mean anatomic lateral distal femoral angle (aLDFA) was 84° (range, 72-89°) and mean anatomic posterior distal femoral angle (aPDFA) was 83° (range, 67-89°). There were 8 nonunions (14%) at 6 month follow-up, and no patients underwent a re-operation for malunion. This case series demonstrates increased revision rates and decreased survivorship of TKA components after surgical management of periprosthetic distal femur fractures. Surgeons must be aware of these potential complications when treating patients with periprosthetic distal femur fractures and counsel their patients appropriately. Therapeutic Level IV. See instructions for all others for a complete description of levels of evidence. • Closed distal femur fractures about a TKA demonstrate a high rate of non-union, 14% at 6-month follow-up. • Following this injury, patients experienced reduced mobility with only 82% being ambulatory after fixation, with 16% still wheelchair bound at 6 months after surgery. • As the number of annual TKA continues to rise, injuries involving those prosthetics will continue to rise.

Comminuted periprosthetic distal femoral fractures have greater postoperative extension malalignment

IntroductionComminution is a significant aspect of periprosthetic distal femoral fracture characterization and may influence post-surgical outcomes. Existing classification systems that guide treatment decisions do not take into account comminution and current literature is unclear on which surgical approach is optimal. We hypothesize that fractures with comminution will have poorer quality post-reduction alignment, especially with a lateral approach. Materials and methods37 study patients were identified with billing codes designating a distal femoral periprosthetic fracture. A retrospective chart review was performed to categorize fractures by absence or presence of comminution and medial parapatellar versus lateral surgical approach. These patients underwent an imaging evaluation for the primary outcome of reduction quality including the anatomic lateral distal femoral angle (LDFA) and the posterior distal femoral angle (PDFA). Differences in radiographic outcomes were analyzed with Wilcoxon/Kruskal-Wallis tests, and analysis by approach was through Fisher's exact test. ResultsPatients with comminuted fractures had significantly greater extension of the fragment (PDFA = 95.4° vs 90.0°, p = 0.018) and similar coronal alignment (LDFA = 85.3° vs 86.3°, p = 0.83) of the knee compared to non-comminuted fractures after surgical reduction. This difference was more prominent amongst those treated with a lateral approach (PDFA = 96.1° vs 89.4°, p = 0.032) than with a medial approach (PDFA = 93.7° vs 91.5°, p = 0.41) (Table 1). DiscussionCurrent classification systems and treatment guidelines for periprosthetic distal femoral fractures do not adequately address several issues that may influence treatment outcomes, especially comminution. Comminuted fractures had greater post-reduction extension malalignment, falling outside the recommended PDFA range of 87–90°, especially with a lateral approach. Consideration should be given to surgical approach and techniques to reduce excessive extension when treating comminuted periprosthetic distal femoral fractures.

Coronal and sagittal alignment of the lower limb in Caucasians: Analysis of a 3D CT database

IntroductionLower limb alignment is a major determinant of long-term outcomes after osteotomy or total knee replacement. The aim of this paper is to define the mean values of coronal and sagittal lower limb alignment for Caucasians as a function of sex using 3D reconstructions from CT-scans. Materials and methodsThe analysis involved 586 Caucasian patients (269 males and 317 females) who had their hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior proximal tibial angle (PPTA), lateral and medial proximal posterior tibial angles (LPPTA/MPPTA), posterior distal femoral angle (PDFA), and non-weightbearing joint convergence angle (nwJLCA) measured. This analysis was performed using a CT-scan-based modelling system (SOMA). Differences between sexes and morphotypes (neutral, varus and valgus) were analyzed statistically. ResultsThe mean HKA was 180±2.57°, LDFA 86.1±1.87°, MPTA 86.1±2.15°, PPTA 84.6±2.58°, LPPTA 84.9±3.17°, MPPTA 85.1±3.21°, PDFA 85.3±1.50° and nwJLCA 0.82±1.32°. There was a significant difference between sexes for the HKA (180.3±2.46° and 179.0±2.52°), LDFA (85.6±1.90° and 86.8±1.61°), MPPTA (84.7±3.06° and 85. 6±3.31°). The neutral morphotype was more frequent in women than men (78% vs. 73%), the varus morphotype was more frequent in men than women (20% vs. 7.6%) and the valgus morphotype was more frequent in women than men (15% vs. 6.7%). ConclusionNormal parameters for lower limb alignment in Caucasian patients were described in the coronal and sagittal planes. There was a significant influence of sex in the coronal plane, which was not found in the sagittal plane. Level of evidenceIV; retrospective cohort study.

No relevant mechanical leg axis deviation in the frontal and sagittal planes is to be expected after subtrochanteric or supracondylar femoral rotational or derotational osteotomy.

The purpose of this study was to investigate if one level of corrective femoral osteotomy (subtrochanteric or supracondylar) bears an increased risk of unintentional implications on frontal and sagittal plane alignment in a simulated clinical setting. Out of 100 cadaveric femora, 23 three-dimensional (3-D) surface models with femoral antetorsion (femAT) deformities (> 22° or < 2°) were investigated, and femAT normalized to 12° with single plane rotational osteotomies, perpendicular to the mechanical axis of the femur. Change of the frontal and sagittal plane alignment was expressed by the mechanical lateral distal femoral angle (mLDFA) and the posterior distal femoral angle (PDFA), respectively. The influence of morphologic factors of the femur [centrum-collum-diaphyseal (CCD) angle and antecurvatum radius (ACR)] were assessed. Furthermore, position changes of the lesser (LT) and greater trochanters (GT) in the frontal and sagittal plane compared to the hip centre were investigated. Mean femoral derotation of the high-antetorsion group (n = 6) was 12.3° (range 10-17°). In the frontal plane, mLDFA changed a mean of 0.1° (-0.06 to 0.3°) (n.s.) and -0.3° (-0.5 to -0.1) (p = 0.03) after subtrochanteric and supracondylar osteotomy, respectively. In the sagittal plane, PDFA changed a mean of 1° (0.7 to 1.1) (p = 0.03) and 0.3° (0.1 to 0.7) (p = 0.03), respectively. The low-antetorsion group (n = 17) was rotated by a mean of 13.8° (10°-23°). mLDFA changed a mean of -0.2° (-0.5° to 0.2°) (p < 0.006) and 0.2° (0-0.5°) (p < 0.001) after subtrochanteric and supracondylar osteotomy, respectively. PDFA changed a mean of 1° (-2.3 to 1.3) (p < 0.01) and 0.5° (-1.9 to 0.3) (p < 0.01), respectively. The amount of femAT correction was associated with increased postoperative deviation of the mechanical leg axis (p < 0.01). Using multiple regression analysis, no other morphological factors were found to influence mLDFA or PDFA. Internal rotational osteotomies decreased the ischial-lesser trochanteric space by < 5mm in both the frontal and sagittal plane (p < 0.001). In case of femAT correction of ≤ 20°, neither subtrochanteric nor supracondylar femoral derotational or rotational osteotomies have a clinically relevant impact on frontal or sagittal leg alignment. A relevant deviation in the sagittal (but not frontal plane) might occur in case of a > 25° subtrochanteric femAT correction. IV.

Outcomes of periprosthetic distal femur fractures following total knee arthroplasty: Intramedullary nailing versus plating

BackgroundPeriprosthetic distal femur fractures (PPDFFs) present a challenge in terms of optimizing fixation in patients with poor bone quality and limited bone stock. The main treatment options include laterally based plating and intramedullary nailing. We hypothesized that treatment of PPDFFs with intramedullary nails would result in improved union rate, fewer complications, and an equivalent rate of malalignment compared to plating. Materials and methodsCases of PPDFFs were identified through a query of our institutional trauma database between 2011-2018. Adult patients (>18 years) were included if they sustained a fracture of the distal femur around a total knee arthroplasty (TKA) that was not initially treated at another institution. The anatomic lateral distal femoral angle (aLDFA) and the anatomic posterior distal femoral angle (aPDFA) were measured on the follow-up radiographs. ResultsNinety-seven PPDFFs in 97 patients, with a mean age of 76 years and 74% female were identified. Plating was used in 74 patients (76%) and 23 patients (24%) were treated with intramedullary nailing. Extension deformity in the sagittal plane was more common following intramedullary nailing compared to plating (10/23 nailing versus 10/74 plating) (p=0.002). There were 12 reoperations (12/75, 16%), and the method of fixation was not associated with rate of reoperation (p=0.9). ConclusionIntramedullary nailing was associated with an increased risk of malalignment, most commonly an extension deformity, in this series. However, malalignment was not associated with worse outcomes.

Application of a new type of angle-adjustable osteotomy guide in closing wedge distal femoral osteotomy

Objective: To explore the feasibility of fast and accurate osteotomy using a new angle adjustable osteotomy guide (AAOG) in closing wedge distal femoral osteotomy(CWDFO). Methods: The clinical data of 14 patients (17 knees) with valgus knee treated with CWDFO at Department of Integrated Chinese and Western Medicine Orthopedics, Honghui Hospital, Xi'an Jiaotong University from January 2018 to July 2019 were analyzed retrospectively. There were 3 males and 11 females, aging (41.4±16.4) years (range: 18 to 56 years). The body mass index was (23.5±3.5) kg/m(2) (range: 18.1 to 28.9 kg/m(2)). The guide pins were placed with the assistance of the self-designed AAOG. Before the surgery, Solidworks software was used to calculate the correction angle and the osteotomy radius accurately. The osteotomy guide was adjusted according to these two parameters. During the surgery, the adjusted osteotomy guide was placed to the surface of bone closely and the guide pins were drilled into the bone through the guide holes. The position of the guide pins was confirmed under fluoroscopy. The osteotomy was finished under guide of pins and fixed with Tomofix plate (Synthes). The times and duration of placement of the guide pins, the times of X-ray examination, the planned and actual thickness of the osteotomy wedge, the top and bottom area of the osteotomy wedge, the posterior distal femoral angle(PDFA), the correction of the weight line, and the American Knee Society Score(AKSS) and Tegner scores were collected and compared by paired t test or Kruskal-Wallis non-parametric test. Healing time after osteotomy and complications were recorded. Results: The guide pins were successfully placed once in 10 knees, adjusted once in 5 knees and twice in 2 knees. The time spent in placing all the 6 pins was 82.4 seconds (range: 51 to 125 seconds), and the times of X-ray examination was 1.5 times (range: 1 to 5 times). The top and bottom areas of the osteotomy wedge were (5.52±0.52)cm(2) and (5.36±0.49)cm(2). PDFA was (85.2±2.6)° preoperatively and (85.5±1.4)° postoperatively (t=-0.401, P>0.05). The thickness of the osteotomy was (11.3±1.9)mm according to the preoperative plan, and the actual thickness was (8.1±1.7)mm. All the patients were followed up for 6 months after surgery and AKSS and Tegner scores improved significantly (all P<0.05). The correction of the weight lines was within the ideal range. Fractures of the hinge point occurred in 3 knees. All of the osseous healing without complications. Conclusion: The new osteotomy guide helps to place the guide pins rapidly and precisely according to the preoperative planning, which should be widely used in clinical applications with promising outcomes.

Effect of surgeon's handedness on distribution of prosthesis during primary total knee arthroplasty

To evaluate the effect of the surgeon's handedness on the distribution of prosthesis during primary total knee arthroplasty (TKA). A retrospective analysis was performed on 86 patients (100 knees) with primary TKA completed by the same right-handed surgeon between December 2016 and December 2018, including 72 cases of single knee and 14 of bilateral knees. The patients were divided into dominant group (right side) and non-dominant group (left side) according to the operating position of the surgeon and each group had 50 knees. There was no significant difference in gender, age, body mass index, disease duration, clinical diagnosis, preoperative Hospital for Special Surgery (HSS) score, and other general data between the two groups ( P>0.05). The operation time and complications were recorded in both groups. The function of knee was evaluated by HSS score. Hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), and mechanical medial proximal tibial angle (mMPTA) were measured by using X-ray film of full-length lower extremity before TKA and at 2 weeks after TKA that were used to evaluate the coronal position of the prosthesis. Posterior distal femoral angle (PDFA) and posterior proximal tibial angle (PPTA) were measured by using lateral X-ray films at 3 months after operation that were used to evaluate the sagittal position of the prosthesis. There was no significant difference in operation time between the two groups ( t=-1.128, P=0.262). One case of posterior tibial artery thrombosis occurred in the dominant group, and 1 case of poor healing of the incision occurred in each of the dominant group and the non-dominant group. Patients in both groups were followed up 12-34 months with an average of 22.0 months. The HSS scores at last follow-up were 87.2±4.3 in the dominant group and 86.8±5.0 in the non-dominant group. There was no significant difference between the two groups ( t=0.471, P=0.639). No complications such as periprosthetic infection, prosthetic loosening, or periprosthetic fracture occurred during follow-up. There was no significant difference in the HKA, mLDFA, and mMPTA between the two groups before and after operation ( P>0.05). The differences in the incidence of sagittal femoral prosthesis malposition and PDFA between the two groups were significant ( P<0.05); however, there was no significant difference in the PPTA, the rate of femoral prosthesis distributed in the neutral position, the incidence of over-flexed femoral prosthesis, and the incidence of anterior femoral notch ( P>0.05). The surgeon's handedness is one of the factors affecting the placement of the sagittal femoral prosthesis in primary TKA. The incidence of sagittal femoral prosthesis malposition could increase when the surgeon performs on the non-dominant side.

Growth modulation for fixed flexion contracture of the knee: a comparison of two techniques.

Growth modulation has become a mainstream treatment for frontal plane angular lower extremity deformities in children. Few articles address the effect of growth modulation on sagittal deformity. Our aim is to compare two anterior distal femoral growth modulation techniques for fixed knee flexion contracture. Electronic medical records were reviewed for patients who underwent anterior femoral growth modulation for fixed flexion contracture. Patients were excluded if adequate preoperative/postoperative radiographs were unavailable. A cohort was subdivided based on surgical technique: screws alone versus dual tension-band plates. Complications were recorded; radiographs were evaluated preoperatively and at hardware removal. Posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA), and anterior cortical line (ACL) angle were evaluated. Of 35 patients identified, 20 patients (29 knees) were included. Thirteen knees were treated with dual anterior tension-band plates; 16 knees had transphyseal screws. Sagittal alignment improved in both groups. Statistically significant PDFA changes were observed in the tension-band plate group (P = 0.0095); a trend was noted toward improvement in ACL angle (P = 0.08). PPTA did not change. No changes reached significance in the transphyseal screw group (PDFA: P = 0.181, ACL: P = 0.64). Tension-band plate migration was noted in one (7.7%) of 13 knees, and transphyseal screw migration in nine (56.3%) of 16 knees (P < 0.01). Anterior distal femoral growth modulation improves sagittal alignment without significant remodeling at the proximal tibia. Hardware migration occurred more often with transphyseal screws (P < 0.01). We recommend dual anterior tension-band plating over placement of paired screws for sagittal growth modulation to treat knee flexion contracture.

Neutral alignment resulting from tibial vara and opposite femoral valgus is the main morphologic pattern in healthy middle-aged patients: an exploration of a 3D-CT database.

Given the goal of achieving optimal correction and alignment after knee arthroplasty or high tibial osteotomy, literature focusing on the inter-individual variability of the native knee, tibia and femur with regards to the coronal or sagittal alignment is lacking. The aim of this study was to analyse normal angular values in the healthy middle-aged population and determine differences of angular values according to inter-individual features. The first hypothesis was that common morphological patterns may be identified in the healthy middle-aged non-osteoarthritic population. The second hypothesis was that high inter-individual variability exists with regards to gender, ethnicity and alignment phenotype. A CT scan-based modelling and analysis system was used to examine the lower limb of 758 normal healthy patients (390 men, 368 women; mean age 58.5 ± 16.4years) with available data concerning angular values and retrieved from the SOMA database. The hip-knee-ankle angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior distal femoral angle (PDFA), posterior proximal tibial angle (PPTA) and non weight-bearing joint line convergence angle (nwJLCA) were then measured for each patient. Results were analysed for the entire cohort and based on gender, ethnicity and phenotype. The mean HKA was 179.4° ± 2.6°, LDFA: 85.8° ± 2.0°, MPTA: 85.6° ± 2.4°, PDFA: 85.2° ± 1.5°, PPTA: 83.8° ± 2.9° and nwJLCA: 1.09° ± 0.9°. Gender was associated with higher LDFA and lower HKA for men. Ethnicity was associated with greater proximal tibial vara and distal femoral valgus for Asian patients. Patients with an overall global varus alignment had more tibia vara and less femoral valgus than patients with an overall valgus alignment. Even if significant differences were found based on subgroup analysis (gender, ethnicity or phenotype), this study demonstrated that neutral alignment is the main morphological pattern in the healthy middle-aged population. This neutrality is the result from tibia vara compensated by an ipsilateral femoral valgus. III, retrospective cohort study.

Reference values of the femur and tibia mechanical axes and angles in the sagittal plane, determined on the basis of three-dimensional modeling

Background: The reference values of the anatomical, mechanical lines and angles of the femur and tibia in the frontal plane have been sufficiently studied. At the same time, the data concerning the mechanical axis and angles in the sagittal plane are rather contradictory. Aims and objectives. The aim of this study was to determine the 3D reference values of the mechanical axes and angles of the femur and tibia in the sagittal plane. Materials and Methods: The study included data of 23 adult volunteers for whom computer tomography (CT) was done. The inclusion criteria were: absence of the deformity confirmed by long-leg films (using known reference lines and angles (RLA) assessment), absence of torsional deformity confirmed by CT and extended position of the limb. Results: It was found that the mechanical axis of the lower limb in the sagittal plane divides the distal joint line of the femur into two segments: anteriorly - 43.8+7.9%, posteriorly - 56.2+7.9%. The proximal joint line of the tibia, correspondingly, is divided into 23.3+8.8% anteriorly and 76.7+8.8% posteriorly. The found values of mechanical angles were the following: mechanical Posterior Proximal Femoral Angle (mPPFA) - 84.7 + 8.8 °, mechanical Posterior Distal Femoral Angle (mPDFA) - 81.1 + 3.95 °, mechanical Posterior Proximal Tibial Angle (mPPTA) - 81.6 + 2.8 °, mechanical Anterior Distal Tibial Angle (mADTA) - 79.9 + 2.98°. Conclusion: The obtained data on the mechanical axis of the lower limb for the sagittal plane can be used both for deformity assessing, planning and estimating the accuracy of deformity correction.

Acute deformity correction and lengthening using the PRECICE magnetic intramedullary lengthening nail

Background: External fixators have been used to treat patients with limb length discrepancy with deformity. Implantable intramedullary (IM) lengthening nails are an attractive alternative achieving accurate results with fewer complications than external fixators. We report on PRECICE™ nail utilization for simultaneous lower limb lengthening and acute deformity correction. Materials and Methods: A retrospective institutional study included a total of 22 segments (13 femurs, 9 tibias; mean age = 17 years) that underwent simultaneous acute deformity correction and lengthening using fixator-assisted nailing and the PRECICE™ IM nail between 2012 and 2015. Results: All segments were corrected with mean final mechanical axis deviation 0.8 cm (0–2.0 cm). Femoral segments achieved frontal plane correction from a preoperative mean lateral distal-femoral angle of 86° to a postoperative mean of 89°; and a sagittal plane correction from a preoperative mean posterior distal femoral angle of 76° to a postoperative mean of 84°. Tibial segments achieved frontal plane correction from a preoperative mean medial proximal tibial angle of 94° to a postoperative mean of 89°; and a sagittal plane correction from a preoperative mean posterior proximal tibial angle of 72° to a postoperative mean of 79°. Rotational malalignment was corrected in all cases based on clinical examination of the rotational profile. The mean length achieved was 4.7 cm. One femoral segment (4.5%) did not achieve the lengthening goal. The mean consolidation index was 42 days/cm. Mean distraction index was 0.7 days/mm. Conclusions: Internal lengthening can permit both lengthening and acute deformity correction, with appropriate preoperative planning, using fixator assisted nailing techniques.

3D printed navigation template-guided minimally invasive percutaneous plate osteosynthesis for distal femoral fracture: A retrospective cohort study

ObjectiveTo evaluate functional and radiological outcomes in distal femoral fracture patients (distal femoral shaft fractures or metaphyseal fractures) receiving indirect reduction and internal fixation with the minimally invasive percutaneous plate osteosynthesis (MIPPO) assisted by 3D printing navigation templates. MethodsThis retrospective study included all adult (≥18 years) patients who underwent MIPPO for distal femoral fracture (AO32/33) at PLA 960 Hospital, Jinan, China between January 1, 2013 and December 31, 2016. 3D printed navigation templates were used to assist surgery. Functional assessment was performed using the Knee Society Score (KSS) and the Functional Knee Society Score (FKSS). Postoperative deformity was assessed with 3D-CT reconstruction using contralateral (non-fracture) side as the reference. ResultsA total of 54 patients underwent MIPPO for distal femoral fracture during the review period (34 and 20 for conventional and template-guided MIPPO, respectively). At 10–14 months, the KSS score was 160.6 ± 18.1 and 167.5 ± 17.2 in the conventional and template-guided MIPPO groups, respectively (p = 0.18). The FKSS was 77.6 ± 9.4 in the conventional MIPPO group vs. 81.0 ± 8.5 in the template-guided MIPPO group (p = 0.15). Femoral length difference was smaller in template-guided MIPPO group (3.31 ± 1.53 vs. 9.50 ± 4.49 mm in the control; p < 0.01). Template-guided MIPPO group also had smaller anatomic lateral distal femoral angle (aLDFA) difference (1.57° ± 0.72° vs. 3.89° ± 1.72° in the control; p < 0.01), anatomic posterior distal femoral angle (aPDFA) difference (1.95° ± 0.78° vs. 5.04° ± 1.78°; p < 0.01), and anteversion angle difference (2.52° ± 1.00° vs. 8.23° ± 4.07°; p < 0.01). The rate of length discrepancy (>20 mm), coronal angulation deformity (aLDFA difference >5°), sagittal angulation deformity (aPDFA difference >10°), and rotational malalignment (anteversion angle >10°) was 5.9%, 20.5%, 2.9%, and 32.4% in the control group. No patients in the template-guided MIPPO group had deformity of any type. ConclusionsMIPPO assisted by 3D printing navigation templates could practically improve surgical accuracy and eliminate postoperative rotational deformity in patients with distal femoral fractures.

Contralateral preoperative templating of lower limbs' mechanical angles is a reasonable option.

In cases where the femur or tibia exhibits abnormal mechanical angulation due to degenerative changes or fracture, the contralateral leg is often used to complete preoperative templating. The aim of this study was to determine the degree of asymmetry between knee joints in healthy individuals and to determine whether it is affected by differing demographic parameters. A CT scan-based modelling and analysis system was used to examine the lower limb of 233 patients (102 males, 131 women; mean age 61.2 ± 15.2years, mean body mass index 24.9 ± 4.4kg/m2) The hip-knee angle (HKA), lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), posterior proximal tibial angle (ppta) and posterior distal femoral angle (PDFA) were then calculated for each patient. Results were then analysed to calculate femoral symmetry based on absolute differences (AD) and percentage asymmetry (%AS) using a previously validated method. Our results do not demonstrate any considerable asymmetry (percentage of asymmetry > 2%) for all the anatomical parameters analysed: HKA (mean AD = 1.5°; mean AS% = 0.8, n.s), MPTA (AD = 1.1°; AS% = 1.3, n.s), PPTA (AD = 1.4°; AS% = 1.0, n.s), LDFA (AD = 1.2mm; AS% = 1.4, n.s) and PDFA (AD = 0.9°; AS% = 1.0, n.s). Gender and ethnicity were not associated with significantly higher AD asymmetry. A significant correlation of AD asymmetry was observed between BMI and HKA, BMI and MPTA, and between patients' age and the MPTA. This data demonstrate that there is a non-statistically significant mechanical angle asymmetry between the two lower limbs. In cases where contralateral templating is used, such asymmetry will induce minimal (if any) clinical differences. IV.

DOES ACL TUNNEL PLACEMENT AFFECT QUALITY OF LIFE IN ADOLESCENTS?

Purpose: The aim of this study was to evaluate the influence of surgical experience of an orthopaedic surgeon on femoral and tibial tunnel placement during anterior cruciate ligament (ACL) reconstruction, and the effect of tunnel angle on patient self-report outcomes. Methods: We retrospectively reviewed 115 consecutive ACL reconstruction surgeries by a single fellowship-trained orthopaedic surgeon over his first 5 years in practice. 70 patients with hamstring (HS) and 44 patients with bone-patellar tendon-bone (BTB) autografts were included, all epiphyseal approaches, graft hybrids or allografts were excluded. Posterior distal femoral angle (PDFA), femoral and tibial tunnel angulation were measured on AP and lateral radiographs by 2 independent raters with high inter-rater reliability (ICC &gt;0.8 for all measures). Tunnel angulation was compared to recently reported ideal femoral angle of 33.5°±1.8 or ideal tibial angle of 62.5°±5 (Luthringer et al, 2016). Complications and self-report outcomes - pediIKDC, Tegner-Lysholm and KOOSChild - were recorded, as well as demographics, injury and surgery characteristics (e.g. concurrent meniscal repairs, chondroplasty, tourniquet time). Average follow-up was 1.14 years. Continuous variables were analyzed using unpaired t-test, Wilcoxon rank sum test and Spearman correlation. Categorical variables were analyzed using Fisher’s exact test. Results: ACL reconstruction was performed at an average age of 16.7 years (range, 11.8 to 20.4 years), 59% males. Figure 1 shows tunnel angles over case groups of N=15. For HS autografts, femoral tunnel angle and tibial tunnel angle improved toward the ideal angle after 15 cases (ANOVA, p=0.020 and p=0.031, respectively). For BTB autografts, femoral tunnel angle and tibial tunnel angle did not demonstrate a significant change over cases (Figure 1). The tibial tunnel angle in HS cases showed a negative weak correlation with the selected outcome scores at 6 months and 1 year after ACL reconstruction, whereas the tibial tunnel angle in BTB cases showed a weak positive correlation with KOOSChild pain scores 6 months after initial surgery (Table 1). For either graft type, femoral tunnel angle was not correlated with any outcome measure. Overall, self-report outcome scores were similar between patients with ideal and non-ideal tunnel angles (data not shown). Of the 70 patients with HS autografts, 5 (7%) required a secondary surgery: 2 revisions for graft tear, 1 revision for a non-functional graft, 1 for arthrofibrosis and 1 for a prominent tibial screw. PDFA, femoral and tibial tunnel angle were similar between patients needing secondary surgery and those who did not (Table 2). Patients needing revision surgery had significantly lower Tegner-Lysholm and KOOSChild Pain scores at 6 months after the initial ACL reconstruction. Of the 44 BTB patients, 3 (6.8%) had complications: 2 patients developed arthrofibrosis and subsequently underwent surgery, and 1 patient experienced neuropathy. In these patients, the PDFA was significantly higher, the femoral tunnel angle significantly lower and tibial tunnel angle similar compared to those without a complication (Table 2). Demographic factors, injury and surgical parameters (concurrent meniscal repairs, chondroplasty, tourniquet time, aso) were similar between HS patients with or without additional surgery and between BTB patients with and without complications. Conclusion/Significance: Femoral and tibial tunnel angle improved towards the reported ideal angle after 15 cases for HS autografts. PDFA, femoral and tibial tunnel angle were not associated with surgical complications in HS patients. For BTB autografts, no significant changes were seen in tunnel placement with surgical experience. Patients experiencing complications after BTB autografts had a low femoral tunnel angle and high PDFA. Overall, tibial tunnel angle, but not femoral tunnel angle, correlated with outcome scores of patients with BTB and HS autografts. [Figure: see text][Table: see text][Table: see text]

Open Supracondylar-Intercondylar Fractures of the Femur Treatment With Taylor Spatial Frame.

To evaluate the Taylor spatial frame (TSF) for primary and definitive fixation of open supracondylar-intracondylar femoral (SIF) fractures. Retrospective. Level I trauma center. Subset of 20 SIF open fractures treated with TSF extracted from a consecutive series of 80 SIF fractures treated between 2007 and 2013. Eighteen (90%) fractures underwent definitive fixation with the TSF; 2 were treated primarily within 24 hours of injury. Mean time interval between primary treatment and secondary TSF was 5 days. Clinical and radiological. Complete union was obtained in 17 (85%) fractures without additional surgery at an average of 33 weeks. Three nonunions and 1 malunion occurred. No deep infection occurred. Results based on Association for the Study and Application of the Method of Ilizarov criteria: 37% excellent, and 63% good for bone outcomes; 5% excellent, 58% good, and 37% fair for functional outcomes. Neer knee scores were 21% excellent, 68% good, and 11% fair. The mechanical lateral distal femoral angle and anatomic posterior distal femoral angle values were within normal range in 80% and 90% of patients, respectively. Abnormal mechanical axis deviation was observed in 4 (20%) cases (2 had associated tibia fractures). Primary and definitive fixation with the TSF are effective. Advantages include continuity of device until union, reduced risk of infection, early mobilization, restoration of primary defect caused by bone loss, easy and accurate application, convertibility and versatility, and improved union rate and range of motion for SIF open fractures. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Accuracy of medial-side cutting guide compared to anterior cutting guide in distal femoral osteotomy of total knee arthroplasty

IntroductionMinimally invasive surgery (MIS) in total knee arthroplasty has the benefits of less postoperative pain and a faster recovery time. An MIS instrument was designed to help surgeons perform this procedure under reduced visualization conditions. A medial cutting guide of the distal femur is used to cut the distal femoral bone without patella subluxation. This study aimed to compare the accuracy of the distal femoral bone cut between the medial and standard anterior cutting guides. Materials and methodsTwo orthopedic surgeons, who specialize in total knee arthroplasty and are familiar with both of these cutting guides, performed the procedures. Forty-eight synthetic saw bones were used, and five-degree valgus medial and anterior cutting guides were randomly assigned to the surgeons. After the osteotomies were performed, the synthetic saw bones were investigated via plain radiographs. Two independent radiologists measured the medial distal femoral angle (MDFA) and the posterior distal femoral angle (PDFA). ResultsThe MDFA in the medial cutting group was statistically significantly different from that of the anterior cutting group (94.18°±1.47° vs. 94.98°±1.14°, P=0.041). However, the PDFA was not different between the two groups. Likewise, the number of outliers was not different between the groups when a±2° error was defined as an outlier (P=0.609 for MDFA and P=0.359 for PDFA). Moreover, a high degree of reliability was found in both MDFA and PDFA measurements (intraclass correlation coefficients=0.813 and 0.824, respectively). ConclusionsIn this experimental study, the MIS medial cutting guide was less accurate than the standard cutting guide in the distal femoral cut.