Femoral Osteotomy Research Articles

Difference in the Extension Gap Between Osteoarthritis and Osteonecrosis in Medial Fixed-Bearing Unicompartmental Knee Arthroplasty with the Spacer Block Technique.

The spacer block technique is widely used in medial fixed-bearing unicompartmental knee arthroplasty (UKA) for osteoarthritis (OA) and osteonecrosis (ON), while it is still unclear if there is any difference in the extension gap between UKAs for the two conditions. To clarify the question, the data from 87 consecutive patients (OA: 57 patients and ON: 30 patients) who underwent medial fixed-bearing UKA with the spacer block technique were retrospectively collected and analyzed. The component gap between the medial tibial osteotomy surface and the femoral trial prosthesis in extension was measured using a UKA tensor, and the preosteotomy gap was calculated in each condition. Also, pre- and postoperative coronal hip-knee-ankle (HKA) angles, the thickness of the insert, and the amount of distal femoral and proximal tibial osteotomy were measured and compared between the two groups. As a result, the mean preosteotomy gap in Group OA and Group ON was 5.4 and 3.7 mm, respectively (p < 0.001). The amount of change in HKA angle following UKA in Group OA and Group ON was 4.4and 3.8 degrees, respectively (p = 0.044), while no significant difference was found regarding pre- and postoperative HKA angle between them. Also, thinner inserts tended to be used in Group ON than in Group OA, while no significant difference in the amount of osteotomies was found between them. Since knees with OA and ON showed different biomechanical conditions at medial fixed-bearing UKA probably for the difference in the amount of remaining cartilage, the surgical technique should be carefully considered for each condition.

Single-cut derotational osteotomy of the distal femur for correction of torsion and frontal axis

Arotational osteotomy requires acomplete cut of the bone in order to correct maltorsion. An additional correction of the frontal axis can be achieved via an oblique cut of the bone. The osteotomy with bone to bone contact is fixed with an angle stable plate. Symptoms such as anterior knee pain, inwardly pointing knee syndrome, lateral patellar subluxation or dislocation, lateral patellar hypercompression syndrome are a common indication for derivational osteotomy if clinically increased femoral internal rotation and radiologically increased femoral antetorsion is detected. Increased hip external rotation versus internal rotation, increased femoral torsion but no increased internal hip rotation, malcompliance, inability for partial weight bearing, risk of delayed union (nicotine abuse and obesity) as well as patellofemoral arthritis and systematic glucocorticoids, immunosuppressants are (relative) contra-indications. Alateral or optionally medial approach to the distal femur and exposure of the bone with Eva hooks for the osteotomy is done. The use of patient-specific cutting blocks accurately specify the planned extent of derotation and level of incision. Adefined oblique cutting plane of the single-cut osteotomy and derotation will additionally correct/change frontal axis. An additional biplanar osteotomy with an anterior wedge increases intraoperative stability and generates alarger bone contact area for consolidation. With the use of an extra medullary fixation devicepartial weight bearing with 15-20 kg with crutches up to 6weeks is required, but no restriction on knee movement is given. The literature shows significantly improved patient satisfaction regarding patellofemoral stability and knee function.With the use of patient-specific cutting guides, high accuracy of the osteotomy and 3‑dimensional correction can be achieved, while delayed union rate is up to 10%.

The Everted Acetabular Labrum: Outcomes of Surgical Management

Background: An everted acetabular labrum (EL) is a pathologic variant in which the labrum is flipped to the capsular side of the acetabular rim. An iatrogenic EL is a known complication of a poorly executed labral repair, and a recent study described the native acetabular EL. Purpose: To analyze surgical outcomes after advancement or reconstruction of an EL in a native hip. Study Design: Cohort study; Level of evidence, 3. Methods: This was a multicenter retrospective review of prospectively collected data on primary hip arthroscopic surgeries performed between 2013 and 2023. An EL was identified arthroscopically as a labrum–femoral head gap while off traction in the native hip. All patients with EL who were analyzed in this study underwent arthroscopic labral repair and advancement or labral augmentation or reconstruction. Patients with hip dysplasia also underwent periacetabular osteotomy with or without a derotational femoral osteotomy. Patient-reported outcomes (PROs) were assessed using the 12-item International Hip Outcome Tool (iHOT-12) and the Nonarthritic Hip Score. PROs were obtained preoperatively and up to 24 months after surgery. PROs were compared with those of a case-matched control cohort in a 1:2 ratio. Only patients with PROs available at ≥1 year postoperatively were included in the outcome analysis. Results: A total of 111 patients (129 hips) with EL during the study period were identified, with PROs available in 96 hips. The mean age of patients with EL was 30.5 years, and women made up 87% of the cohort. Of the 129 hips with an EL, an isolated diagnosis of an EL was present in 11.6% of hips. Deficient acetabular coverage (lateral center-edge angle <25°) was seen in 40.6% of EL hips. No difference was seen in iHOT-12 scores between EL and control groups at 12- or 24-month follow-up (P = .18 and .94, respectively). Patients with EL reported a significant improvement of PROs at latest follow-up (P < .001 for iHOT-12 and Nonarthritic Hip Score). Conclusion: Surgical management of a native EL with restoration of the labral seal on the femoral head and correction of concomitant pathologies resulted in significant clinical improvement, with postoperative outcome scores comparable to those of patients without an EL. These findings provide evidence supporting surgical intervention for a native EL.

External Fixator Stabilization Following Open Reduction and Combined Pelvic and Proximal Femur Osteotomy in Developmental Dysplasia Hip: A Surgical Note

Introduction: Maintenance of hip joint reduction after combined pelvic and femoral osteotomy in developmental dysplasia of the hip (DDH) in children using a hip-spica cast has the potential to cause numerous cast-related complications. We proposed a modification of the surgical technique where the hip reduction is maintained with an external fixator to avoid cast-related complications. Methodology: The surgical technique involved the placement of Scahnz pins along the iliac crest or lateral aspects of the ilium, in the supra-acetabular region below the pelvic osteotomy site, and the proximal femur. The pins were connected and stabilized with tubular/solid rods. Six children with 10 dysplastic hips [4 bilateral and 2 unilateral, International Hip Dysplasia Institute (IDHI) grade IV] were operated on with pelvic and femoral osteotomies and external fixator construct. The fixators were removed after 8 weeks and the children were followed up at 3, 6, 12, and 18 months. Results: The average age of the children was 6.5 years (range: 4 to 11 y). After an average follow-up of 10 months, the hips were reduced with IDHI grade of I in 7 hips and IDHI grade of II in 3 hips. There were no wound complications. Superficial pin tract infections were seen in all patients but responded to topical antibiotic application. There was no unplanned visit by the parents and no one complained of perineal hygiene issues. Conclusion: The external fixator construct maintains the hip reduction in DDH and allows the osteotomy sites to heal without any wound-related complications.

Does Size Really Matter? Incidence of Periprosthetic Fractures After Femoral Osteotomy in Patients With Cerebral Palsy.

Of children, 30% to 35% with cerebral palsy (CP) develop hip subluxation or dislocation and often require reconstructive hip surgery, including varus derotation osteotomy (VDRO). A recent literature review identified postoperative fractures as the most common complication (9.4%) of VDROs. This study aimed to assess risk factors for periprosthetic fracture after VDRO in children with CP. A total of 347 patients (644 hips, 526 bilateral hips) with CP and hip subluxation or dislocation (129 females; mean age at index VDRO: 8.6 y, SD 3.4, range: 1.5 to 17.7; 2 Gross Motor Function Classification System (GMFCS) I, 35 GMFCS II, 39 GMFCS III, 119 GMFCS IV, 133 GMFCS V, 21 unavailable) were included in this retrospective, single-group intervention (VDRO) study at a tertiary referral center. Imaging and clinical documentation for patients age 18 years or younger at index surgery, treated with VDRO were reviewed to determine demographic data, GMFCS level, surgeon, type of hardware implanted, use of anticonvulsants and steroids, type of postoperative immobilization, presence of periprosthetic fractures, fracture location and mechanism, and time from surgery to fracture. Potential determinants of periprosthetic fractures were assessed using mixed effects logistic regression. Of 644 hips, 14 (2.2%, 95% CI: 1.3%, 3.6%) sustained a periprosthetic fracture, at a median of 2.1 years postoperatively (interquartile range: 4.6 y, range: 1.2 mo to 7.8 y). Patients with a fracture had a median age at index surgery of 7.3 years (interquartile range: 4.3, range: 2.8 to 17.8; 1 GMFCS II, 6 GMFCS IV, 7 GMFCS V). Periprosthetic fractures were not significantly related to age at index surgery ( P = 0.18), sex ( P = 0.30), body mass index percentile ( P = 0.87), surgery side ( P = 0.16), anticonvulsant use ( P = 0.35), type of postoperative immobilization ( P = 0.40), GMFCS level ( P = 0.31), or blade plate size ( P = 0.17). Only surgeon volume significantly related to periprosthetic fracture (odds ratio = 5.03, 95% CI: 1.53, 16.56, P = 0.008), with the highest-volume surgeon also using smaller blade plates ( P < 0.01). Periprosthetic fractures after VDRO surgery in children with CP are uncommon, and routine hardware removal appears unnecessary. The data suggest that the common dogma of putting in the largest blade plate possible to maximize fixation may increase the risk of periprosthetic fracture. Due to the overall low fracture rate, especially when contextualized relative to the risk of hardware removal, a reactive approach to hardware removal appears warranted. Level III-retrospective study (targeting varus derotational osteotomies in children with cerebral palsy).

Deformity in valgus knee malalignment is not only in the femurbut also in tibia or both, based on demographic and morphological analysis before and after knee osteotomies.

This study aims to identify the demographic and morphological features of valgus knee deformity with unilateral osteoarthritic knee in the coronal plane. A secondary aim was to identify the distinct phenotypes of valgus knees in Hirschmann's phenotype and the coronal plane alignment of the knee (CPAK) classifications before and after a knee osteotomy (KO). A total of 107 patients (57 female and 50 male) with a mean age of 42.4 ± 17.2 years, who underwent varisation osteotomy for symptomatic unilateral knee osteoarthritis (OA) and constitutional valgus deformity, were enrolled in the study, and the mean follow-up period was 29.1 ± 7.3 months. The included cases comprised 60 cases of distal femoral osteotomy, 10 cases of double-level osteotomyand 33 cases of high tibial osteotomy. All patients underwent preoperative and postoperative clinical, functional and radiological evaluations, analysed by analysis of variance tests. An analysis of the location of the valgus deformities demonstrated that 56 cases (52.3%) were femoral based, 18 cases (16.8%) were both femoral and tibial basedand 33 cases (30.9%) were tibial based. Twelve preosteotomy cases (11.2%)and 38 postosteotomy cases (35.5%) matched the most common eight Hirschmann's phenotypes, phenotyping the coronal lower limb alignment based on the native alignment in young patients without OA. Four (3.7%) preosteotomy cases and 89 postosteotomy cases (83.1%) matched the most common three CPAK phenotypes (Ⅰ, Ⅱ, Ⅴ) based on constitutional alignment and joint line obliquityin healthy and osteoarthritic knees. In valgus knee malalignment, the location of the deformity is not only solely femoral-basedbut also solely tibial-based or combined femoral and tibial-based. An individualised osteotomy approach would be recommended to achieve careful preoperative planning that considers the location of the deformity and the resultant joint line. Hirschmann's and CPAK classification would not be relevant when KO is considered. Level Ⅳ, retrospective case-control study.

Treatment of Hip Displacement in Children With Cerebral Palsy: A 5-year Comparison of Proximal Femoral Osteotomy and Combined Femoral-Pelvic Osteotomy in 163 Children.

This study compared the 5-year outcomes of isolated proximal femoral varus osteotomy (FO) and combined proximal femoral varus and pelvic osteotomy (FPO) for the treatment of hip displacement in children with cerebral palsy (CP) in Sweden, focusing on the number of reoperations and residual hip displacement. The study included 163 children with a 5-year follow-up after FO or FPO in the national Swedish CP surveillance program, CPUP. Descriptive statistics and univariate and multivariate Cox regression analyses were used to identify whether the age at surgery, sex, Gross Motor Function Classification System level, CP dominant symptom, hip migration percentage (MP), type of surgery (unilateral/bilateral), and history of soft tissue hip surgery were related to the 5-year outcomes after surgery. Failure after hip surgery was defined as a skeletal reoperation involving the hip and/or MP >50%. During the period 2001 to 2017, 163 children (65 girls) underwent 246 femoral and/or pelvic osteotomies (154 FO, 47 bilaterally; 92 FPO, 16 bilaterally) and had a 5-year follow-up; 95 and 74 children had ≥1 FO or FPO as the primary skeletal surgery, respectively. The mean preoperative MP (51%±18% for FO and 59%±17% for FPO, P =0.001) and age at surgery (6.2±2.5 years for FO and 7.3±2.8 years for FPO, P =0.014) differed between procedures. At the 5-year follow-up, 5 hips (5%) had reoperations and 5 hips (5%) had radiological failure among the 92 FPOs, and 33 (21%) had reoperations and 14 (9%) radiological failure among the 154 FOs. The difference in outcome failure rate was significant ( P <0.001). Multivariate Cox regression analysis showed a lower risk for failure with FPO [hazard ratio (HR)=0.32, 95% CI: 0.15-0.68] compared with FO. A higher preoperative MP increased the risk for outcome failure (HR=1.21, 95% CI: 1.15-1.36 for each 5% increment). FPO had a higher mean preoperative MP but a lower 5-year outcome failure rate compared with FO. A higher preoperative MP was associated with an increased risk of failure. Level II-prospective comparative study.

Valgus malalignment causes increased forces on a medial collateral ligament reconstruction under dynamic valgus loading: Abiomechanical study.

To investigate the forces on a medial collateral ligament (MCL) reconstruction (MCLR) relative to the valgus alignment of the knee. Eight fresh-frozen human cadaveric knees were subjected to dynamic valgus loading at 400 N using a custom-made kinematics rig. After resection of the superficial medial collateral ligament, a single-bundle MCLR with a hamstring tendon autograft was performed. A medial opening wedge distal femoral osteotomy was performed and fixed with an external fixator to gradually adjust the alignment in 5°increments from 0° to 10° valgus. For each degree of valgus deformity, the resulting forces acting on the MCLR were measured through a force sensor and captured in 15° increments from 0° to 60° of knee flexion. Irrespective of the degree of knee flexion, increasing valgus malalignment resulted in significantly increased forces acting on the MCLR compared to neutral alignment (p < 0.05). Dynamic loading at 5° valgus resulted in increased forces on the MCLR at all flexion angles ranging between 16.2 Nand 18.5 N (p < 0.05 from 0° to 30°; p < 0.01 from 45° to 60°). A 10° valgus malalignment further increased the forces on the MCLR at all flexion angles ranging between 29.4 Nand 40.0 N (p < 0.01 from 0° to 45°, p < 0.05 at 60°). Valgus malalignment of the knee caused increased forces acting on the reconstructed MCL. In cases of chronic medial instabilities accompanied by a valgus deformity ≥ 5°, a realigning osteotomy should be considered concomitantly to the MCLR to protect the graft and potentially reduce graft failures. Level III.

Treatment of bilateral developmental dysplasia of the hip joint with an improved technique: A case report

BACKGROUND Developmental dysplasia of the hip (DDH) is a common osteoarticular deformity in pediatric orthopedics. A patient with bilateral DDH was diagnosed and treated using our improved technique "(powerful overturning acetabuloplasty)" combined with femoral rotational shortening osteotomy. CASE SUMMARY A 4-year-old girl who was diagnosed with bilateral DDH could not stand normally, and sought surgical treatment to solve the problem of double hip extension and standing. As this child had high dislocation of the hip joint and the acetabular index was high, we changed the traditional acetabuloplasty to "powerful turnover acetabuloplasty" combined with femoral rotation shortening osteotomy. During the short-term postoperative follow-up (1, 3, 6, 9, 12, and 15 months), the child had no discomfort in her lower limbs. After the braces and internal fixation plates were removed, formal rehabilitation training was actively carried out. CONCLUSION Our "powerful overturning acetabuloplasty" combined with femoral rotational shortening osteotomy is feasible in the treatment of DDH in children. This technology may be widely used in the clinic.

'One millimetre equals one degree' is a major source of inaccuracy in planning osteotomies around the knee for metaphyseal deformities compared to the digital planning.

The objective of this study was to compare the accuracy of virtually performed osteotomies around the knee. The comparison was made between the Miniaci method (method 1), considered the gold standard planning, with the widely held dogma that one degree of correction required equates to one millimetre of opening/closing (method 2). This retrospective cross-sectional study was conducted between December 2018 and September 2022 in patients aged at least 15 years with metaphyseal knee deformity. Osteotomy planning was performed in methods 1 and 2 utilising calibrated long-leg alignment X-rays in the frontal plane. In both methods, the desired correction was defined by the Fujisawa point. The error % in measurement (ratio method 1/method 2) and the difference in millimetres (method 1 - method 2) between the two methods were analysed. A total of 107 osteotomies with 27 (25.2%) distal femoral osteotomies, 54 (50.5%) proximal tibial osteotomies and 26 (24.3%) double-level osteotomies were performed virtually with a mean hip-knee-ankle angle of 176.4 ± 6.6. In distal femur osteotomy, the mean error % between methods 1 and 2 was 38.9 ± 16.7% and 22.4 ± 16.8% for the opening and closing groups, respectively. In proximal tibial osteotomies, the mean error % was 22.7 ± 15.6% and 9 ± 10.8% for the opening and closing groups, respectively. In double-level osteotomy, the mean error % of femur-based corrections was 34.9 ± 19% and 19.5 ± 21% for the opening and closing groups, respectively, and the mean error of the tibial-based corrections was 26.4 ± 12.1% for the opening group and 10.8 ± 10% for the closing group, respectively. Planning one millimeter per degree of desired correction for osteotomies around the knee in metaphyseal deformities is a major source of error when compared with digital planning using the Miniaci method. This was seen most frequently with osteotomies of the distal femur and all opening wedge osteotomies. Level Ⅲ, retrospective cross-sectional study.

Distal femoral osteotomy and patellar tendon advancement for the treatment of crouch gait in patients with bilateral spastic cerebral palsy

BackgroundCrouch gait, or flexed knee gait, represents a common gait pattern in patients with spastic bilateral cerebral palsy (CP). Distal femoral extension and/or shortening osteotomy (DFEO/DFSO) and patellar tendon advancement (PTA) can be considered as viable options when knee flexion contractures are involved. Better outcomes have been reported after a combination of both, independently of the presence of knee extensor lag. In this study, we evaluated the clinical and kinematic outcomes of these procedures. Patients and methodsWe reviewed a cohort of 52 limbs (28 patients) who were treated for crouch gait by DFEO/DFSO alone (group 1, n = 15) or DFEO/DFSO + PTA (group 2, n = 37) as a part of single event multilevel surgery (SEMLS). The mean age at surgery was 14 years, and the mean follow-up time was 18 months. The physical examination data and three-dimensional standardized gait analysis were collected and analyzed before the surgery and postoperatively. ResultsOverall knee range of motion improved in all limbs. The knee flexion decreased significantly in both groups at initial, mid, and terminal stance. Hip flexion significantly decreased in mid-stance for limbs in group 2. Both clinical and gait parameters were most improved in limbs who underwent DFEO/DFSO + PTA. Increased pelvic tilt was observed in both groups after surgery. ConclusionAlthough DFEO/DFSO alone was successful in correcting knee flexion contractures, PTA has helped to improve knee extensor lag and knee extension during gait. Level of evidenceTherapeutic level IV

Soft Tissue Stabilization of the Hinge Position for Lateral Closing-Wedge Distal Femoral Osteotomy: An Anatomic Study.

Soft tissue plays an important role in stabilizing the hinge point for osteotomy around the knee. However, insufficient data are available on the anatomic features of the soft tissue around the hinge position for lateral closing-wedge distal femoral osteotomy (LCWDFO). To (1) anatomically analyze the soft tissue around the hinge position for LCWDFO, (2) histologically analyze the soft tissue based on the anatomic analysis results, and (3) radiologically define the appropriate hinge point to prevent unstable hinge fracture based on the results of the anatomic and histological analyses. Descriptive laboratory study. In 20 cadaveric knees (age, 82.7 ± 7.8 years; range, 60-96 years), the soft tissue of the distal medial side of the femur was anatomically analyzed. The thicknesses of the periosteum and direct insertion of the adductor tendon (AT) were histologically examined and measured using an electron microscope. The thickness of the periosteum was visualized graphically, and the graph of the periosteum and radiograph of the knee were overlaid using image editing software. The appropriate hinge position was determined based on the periosteal thickness and attachment of the AT. The mean thickness of the periosteum of the metaphysis was 352.7 ± 58.6 µm (range, 213.6-503.4 µm). The overlaid graph and radiograph revealed that the thickness of the periosteum changed at the part corresponding to the transition between the diaphyseal and metaphyseal ends of the femur. The mean width of the AT attached to the distal medial femur from the adductor tubercle toward the distal direction was 7.9 ± 1.3 mm (range, 6.3-9.7 mm). Results indicated that the periosteum and AT support the hinge for LCWDFO within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle. When the hinge point is located within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle, these soft tissues work as stabilizers, and there is no risk of cutting into the joint space.

Effect of Varus-Producing Distal Femoral Osteotomy and High Tibial Osteotomy on Compartment Pressures and Contact Area at Varying Degrees of Knee Flexion.

In patients with valgus alignment and degenerative changes in the lateral compartment, both distal femoral osteotomy (DFO) and high tibial osteotomy (HTO) can be used to unload the lateral compartment. Prior studies have shown that in valgus knees, the tibial wear is posterior and DFO exerts the greatest effect in extension; however, its effect is decreased as flexion angle rises. Medial closing-wedge (MCW) HTO would significantly decrease contact area, mean contact pressure (MCP), and peak contact pressure (PCP) in the lateral knee compartment through knee flexion to a greater extent compared with lateral opening-wedge (LOW) DFO. Controlled laboratory study. MCWHTO and LOWDFO were performed, correcting a mean of 8° of valgus alignment, in 10 cadaveric knees using plate fixation. Tibiofemoral contact pressure of the medial and lateral compartments was measured in 0°, 30°, 60°, and 90° of knee flexion before and after osteotomy using thin electronic sensors and load applied through an Instron device. PCP, MCP, and contact area were measured for each condition. The lateral MCP was significantly decreased in the HTO state compared with the native state in 30° (P = .015), 60° (P = .0199), and 90° (P < .0001) of flexion. The lateral MCP was also significantly decreased in the HTO state when compared with the DFO state in 60° (P = .0093) and 90° of flexion (P < .0001). After DFO, the lateral MCP returned to that of the native state in 60° (P > .999) and 90° (P > .999) of flexion. The lateral PCP decreased for all test states in all degrees of flexion; the HTO state was significantly decreased when compared with the native state in 60° (P < .0001) and 90° (P < .0001). With varus corrections of 8°, MCWHTO was more effective at unloading the lateral compartment than LOWDFO. This effect was significant as the knee flexion angle increased. This study should be considered as one aspect of the surgical decision-making process. In patients with mild to moderate valgus deformity without hypoplastic lateral femoral condyle and without significant joint line obliquity, MCWHTO may improve offloading of the lateral compartment in flexion.

Measuring Parallelism to the Ground in Bipedal Stance Phase: Mechanical Versus Kinematic Alignment in Total Knee Arthroplasty.

Introduction The goal of total knee arthroplasty is to replace diseased cartilage and bone with an artificial implant to improve the patient's quality of life. The knee has historically been reconstructed to the patient's mechanical axis (MA). However, kinematically aligned techniques have been increasingly used. Kinematic alignment requires less soft-tissue resection and aligns the knee with what is anatomically natural to the patient, while there is concern that kinematically aligned knees will lead to earlier failure due to potential unequal weight distribution on the implant. The purpose of this study is to compare the parallelism from the floor of the joint-line cuts using kinematic and mechanical alignment and understand if the MA is a proper estimation of the tibial-ankle axis (TA). Methods A retrospective study was conducted by recruiting all high tibial osteotomy and distal femoral osteotomy recipients operated on by two surgeons in two MedStar Health hospitals from 01/2013 to 07/2020 with full-length films in preparation for restorative procedures. Baseline osteoarthritis was graded using the Kellgren-Lawrence classification system with all patients presenting as Grade 0. The TAand the joint-line orientations of the MAand kinematic axis (KA) were measured on 66 legs. The average distance from parallelism to the ground was compared between the MA and the KA and between the MA and the TA using a paired t-test. Results KA joint-line orientation (1.705° deviation) was more parallel to the floor in the bipedal stance phase than the MA (2.316° deviation, p=0.0156). The MA (2.316° deviation) was not a proper estimation of the TA (4.278° deviation, p=0.0001). Conclusion By utilizing the KA technique, the restoration of the natural joint line, as well as a joint that is more parallel to the floor in the stance phase compared to the MA, is achieved.The parallelism to the ground of the KAduring the bipedal stance phase suggests an even load distribution across the knee.In addition, due to its similarity to the KA and anatomical significance in weight-bearing distribution, further investigation into the hip-to-calcaneal axis as an approximation of the joint line is warranted.

Biomechanical Comparison of Uniplanar versus Biplanar Lateral Opening-wedge Distal Femoral Osteotomy Techniques in Terms of Risk for Medial Hinge Fracture.

The effect of osteotomy type on the initial stiffness of the bone-implant construct in lateral opening-wedge distal femoral osteotomy (LOWDFO) using a uniplanar compared with a biplanar technique has been investigated. However, no study has explored the biomechanical risk factors for medial hinge fracture. This study aimed to compare the biomechanical strength of uniplanar versus biplanar LOWDFO regarding the risk for medial hinge fracture during gap opening. Twelve composite femora were divided into two groups (six in each group) based on the distal femoral osteotomy technique: uniplanar versus biplanar LOWDFO. All LOWDFO models were subjected to incremental static loading. The gap distance was expanded by 1 mm, and displacement values were recorded as anterior and posterior gap distances (mm). The average force values of all samples at certain gap distances were recorded, and the head distance was measured. The uniplanar group had higher load values than the biplanar group at all anterior gap distances. These differences were only significant at 2- and 3-mm gap distances (p = 0.025 and 0.037). At all posterior gap distances, the uniplanar group had higher load values than the biplanar group, but these differences only reached statistical significance at 2 mm (p = 0.037). Both groups had similar anterior, posterior, and average gap distances (p = 0.75, 0.522, 0.873). The uniplanar group had a higher head insertion distance (15.3 ± 5.7) than the biplanar group (14.7 ± 2.9), but it was not significant (p = 0.87). The uniplanar group had a lower average load before medial hinge fracture (46.41 ± 13.91 N) than the biplanar group (54.92 ± 31.94, p = 0.81). The biplanar group had an average maximum load value of 64.18 ± 25.6 N, while the uniplanar group had 57.90 ± 12.21 N (p = 0.81). This study revealed that the biplanar osteotomy technique allows a wider opening wedge gap with less risk of a medial hinge fracture than uniplanar LOWDFO.Level of evidence was level 3, case-control series.

Saw-box osteotomy versus reamer-box osteotomy in posterior stabilized total knee arthroplasty: a retrospective study of an average fiveyear follow-up.

The purpose of this study is to compare the difference of results between two methods of femoral box osteotomy adopted by two designs of posterior stabilized total knee prostheses. Retrospective analysis of the results of two groups of patients operatedupon using two primary PS TKA systems, PFC Sigma (DePuy Synthes, Johnson and Johnson®) and Genesis II prosthesis (Smith and Nephew®), with an average of fiveyear follow-up was done. Group 1 included 152 knees in 121 patients and group 2 included 122 knees in 111 patients. The average follow-up period in both groups was fiveyears. The box osteotomy method depends on bone saw in group 1, and bone reamer in group 2. The KSS score of group 2 was better in the first sixmonths postoperatively. Then, no significant differences were seen in the remaining follow-up visits. The risk of periprosthetic fractures was significantly higher in group 1 (p-value 0.040). Survival analysis showed a significantly shorter time for reoperation in group 1 than in group 2 as described by log-rank test, (p < 0.006). The method of box cutting has an impact on the function and longevity of posterior stabilized primary knee implants. The risk of periprosthetic fractures can be reduced by proper patient selection, decreasing the box sizes, and development of more "controlled" box osteotomy instruments.

Varus osteotomy as a salvage procedure for young patients with symptomatic patellofemoral arthritis and valgus malalignment at short- to mid-term follow-up: a case series

PurposeThe purpose of the study was to report the clinical, functional and radiological outcome following varus osteotomy as a salvage procedure in young to middle-aged patients with patellofemoral arthritis (PFA) and associated valgus malalignment. It was hypothesized that a significant improvement in knee function and reduction in pain would be achieved. Moreover, no conversion to patellofemoral joint arthroplasty could be observed.Material and methodsPatients (< 50 years of age) that underwent varus osteotomy between 08/2012 and 01/2020 for the treatment of symptomatic PFA and associated valgus malalignment were consecutively included (minimum follow-up: 24 months). Patient-reported outcome measures (PROM; International Knee Documentation Committee subjective knee form [IKDC]), Visual Analog Scale [VAS] for pain, Tegner Activity Scale [TAS], and satisfaction with the postoperative results (1–10-scale, 10 = highest satisfaction) and weight-bearing whole-leg anteroposterior radiographs were conducted pre- and postoperatively. The change in PROM and femorotibial angle (FTA) were tested for statistical significance.ResultsIn total, 12 patients (14 knees) were included (66.7% female; mean age: 33.8 ± SD 6.6 years). In ten cases, lateral opening-wedge distal femoral osteotomies (DFO) were performed, of which three cases included a concomitant femoral derotation. Three medial closing-wedge DFO and one medial closing-wedge high tibial osteotomy were performed. At follow-up (55.3 ± 29.3 months), a significant improvement in knee function (IKDC: 56.4 ± 14.4 to 69.1 ± 11.2, p = 0.015) and reduction in pain (VAS for pain: 3.5 [interquartile range 2.3–5.8] to 0.5 [0–2.0], p = 0.018) were observed. Patients were able to reach their preoperative sporting activity level (TAS: 3.0 [3.0–4.0] to 3.5 [3.0–4.0], p = 0.854) and were highly satisfied with the postoperative result (9.0 [6.5–10]). Additionally, a significant correction of valgus malalignment was observed (5.0° ± 2.9° valgus to 0.7° ± 3.2° varus, p < 0.001). Regarding complications, two re-osteosyntheses were performed due to loss of correction and delayed union. No conversion to patellofemoral arthroplasty occurred.ConclusionIn patients with symptomatic PFA and associated valgus malalignment, varus osteotomy as a salvage procedure achieved a significant improvement in knee function and reduction in pain. No conversion to patellofemoral joint arthroplasty occurred at short- to mid-term follow-up.Level of evidenceRetrospective case series, Level IV.

Exposure of Hoffa Fractures Is Improved by Posterolateral and Posteromedial Extensile Approaches: A Qualitative and Quantitative Anatomical Study.

The current literature lacks recommendations regarding surgical approaches to best visualize and reduce Hoffa fractures. The aims of this study were to (1) define surgical corridors to the posterior portions of the lateral and medial femoral condyles and (2) compare the articular surface areas visible with different approaches. Eight fresh-frozen human cadaveric knees (6 male and 2 female donors; mean age, 68.2 ± 10.2 years) underwent dissection simulating 6 surgical approaches to the distal femur. The visible articular surface areas for each approach were marked using an electrocautery device and subsequently analyzed using image-processing software. The labeled areas of each femoral condyle were statistically compared. At 30° of flexion, visualization of the posterior portions of the lateral and medial femoral condyles was not possible by lateral and medial parapatellar approaches, as only the anterior 29.4% ± 2.1% of the lateral femoral condyle and 25.6% ± 2.8% of the medial condyle were exposed. Visualization of the lateral femoral condyle was limited by the posterolateral ligamentous structures, hence a posterolateral approach only exposed its central (13.1% ± 1.3%) and posterior (12.4% ± 1.1%) portions. Posterolateral extension by an osteotomy of the lateral femoral epicondyle significantly improved the exposure to 53.4% ± 2.7% and, when combined with a Gerdy's tubercle osteotomy, to 70.9% ± 4.1% (p < 0.001). For the posteromedial approach, an arthrotomy between the anteromedial retinaculum and the superficial medial collateral ligament, and one between the posterior oblique ligament and the medial gastrocnemius tendon, allowed visualization of the central (13.5% ± 2.2%) and the posterior (14.6% ± 2.3%) portions of the medial femoral condyle, while a medial femoral epicondyle osteotomy significantly improved visualization to 66.1% ± 5.5% (p < 0.001). Visualization of the posterior portions of the femoral condyles is limited by the specific anatomy of each surgical corridor. Extension by osteotomy of the femoral epicondyles and Gerdy's tubercle significantly improved articular surface exposure of the femoral condyles. Knowledge of the surgical approach-specific visualization of the articular surface of the femoral condyles might be helpful to properly reduce small Hoffa fragments.

Evaluation of the long-term patient-reported outcomes after hip arthroplasty or joint preserving with Sugioka femoral osteotomy in patients with femoral head osteonecrosis

PurposeThis study retrospectively evaluated long-term clinical outcomes and patient-reported outcome measures (PROMs) in patients with osteonecrosis of the femoral head (ONFH) who underwent transtrochanteric rotational osteotomy (TRO), curved varus osteotomy (CVO), and total hip arthroplasty (THA).MethodsWe retrospectively reviewed the 109 hips in 96 patients (46 men, 50 women) who underwent CVO, TRO, or THA for ONFH treatment. The mean follow-up period for the TRO, CVO, and THA groups was 14.8, 11.5, and 13.3 years, respectively.ResultsThe THA conversion rate of the TRO patients was significantly higher than that of the patients with CVO, and the final clinical scores in the patients with TRO did not improve compared with preoperative scores. Postoperative PROMs showed that the total and pain scores of the patients with THA were significantly higher than those of patients with TRO and CVO, while the PROM score did not change between patients with TRO and CVO. The analysis further showed that the preoperative type C2, stage 3A, or postoperative type C1 and C2 were significant predictors of decreased final PROM scores.ConclusionThis study found that CVO and THA are clinically effective treatments for ONFH, with significant improvements compared with preoperative scores. However, THA was associated with significantly higher PROMs and pain scores than those of CVO and TRO in long-term follow-up. Furthermore, our results suggest that postoperative PROMs depend mainly on the preoperative level of collapse and postoperative transposed intact ratio of the articular surface of the femoral head.

Multi-segment osteotomy with interlocking intramedullary nail fixation in the treatment of lower limb deformity in older children with hypophosphatemic rickets.

Malformations of the lower limbs caused by hypophosphatemic rickets in older children are mostly complex, occurring on multiple planes without a single apex and showing arcuate bending of the diaphysis combined with torsion deformity, and are difficult to correct. This study retrospectively investigated the effect of and indicators for multi-segment osteotomy with interlocking intramedullary nail fixation in the treatment of bony deformity caused by hypophosphatemic rickets. The clinical data of 21 hypophosphatemic rickets patients seen between August 2007 and March 2022 were collected. The age range of the patients at the first surgery was 11 years and 1 month old to 15 years and 3 months old, with an average age of 12 years and 8 months. There were 6 males and 15 females. All patients had abnormal alignment of their lower limbs, with 32 limbs having varus deformity and 10 limbs having valgus deformity. A total of 67 surgeries were performed across the 21 patients, including 24 cases of femoral osteotomy with antegrade intramedullary nail fixation, 6 cases of femoral osteotomy with retrograde intramedullary nail fixation, and 20 cases of tibial osteotomy with interlocking intramedullary nail fixation. A total of 34 limbs eventually underwent interlocking intramedullary nail fixation, 9 with genu valgum and 25 with genu varus. All 21 patients were followed up for a period of 14∼96 months, with an average of 42.6 months. The ends of the osteotomies achieved bony union in 4-9 months (average 6.8 months), after which normal weight-bearing walking could be resumed. No infection, vascular or neurological complications, or nonunion occurred. During postoperative follow-up, the alignment the lower limbs passed through zone 1 in 13 limbs, zone 2 in 12 limbs, and zone 3 in 5 limbs. The overall rate of an excellent effect was 83.3%. For lower limb deformity caused by hypophosphatemic rickets in older children, multi-segment osteotomy and strong fixation with interlocking intramedullary nails can achieve good correction outcomes.