Aims. The Coronal Plane Alignment of the Knee (CPAK) classification is a simple and comprehensive system for predicting pre-arthritic knee alignment. However, when the CPAK classification is applied in the Asian population, which is characterized by more varus and wider distribution in lower limb alignment, modifications in the boundaries of arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) should be considered. The purposes of this study were as follows: first, to propose a modified CPAK classification based on the actual joint line obliquity (aJLO) and wider range of aHKA in the Asian population; second, to test this classification in a cohort of Asians with healthy knees; third, to propose individualized alignment targets for different CPAK types in kinematically aligned (KA) total knee arthroplasty (TKA). Methods. The CPAK classification was modified by changing the neutral boundaries of aHKA to 0° ± 3° and using aJLO as a new variable. Radiological analysis of 214 healthy knees in 214 Asian individuals was used to assess the distribution and mean value of alignment angles of each phenotype among different classifications based on the coronal plane. Individualized alignment targets were set according to the mean lateral distal femoral angle (LDFA) and
The aim of mechanical alignment in total knee arthroplasty is to align all knees into a fixed neutral position, even though not all knees are the same. As a result, mechanical alignment often alters a patient’s constitutional alignment and joint line obliquity, resulting in soft-tissue imbalance. This annotation provides an overview of how the Coronal Plane Alignment of the Knee (CPAK) classification can be used to predict imbalance with mechanical alignment, and then offers practical guidance for bone balancing, minimizing the need for soft-tissue releases. Cite this article:
Orthopaedic surgeons are currently faced with an overwhelming number of choices surrounding total knee arthroplasty (TKA), not only with the latest technologies and prostheses, but also fundamental decisions on alignment philosophies. From ‘mechanical’ to ‘adjusted mechanical’ to ‘restricted kinematic’ to ‘unrestricted kinematic’ — and how constitutional alignment relates to these — there is potential for ambiguity when thinking about and discussing such concepts. This annotation summarizes the various alignment strategies currently employed in TKA. It provides a clear framework and consistent language that will assist surgeons to compare confidently and contrast the concepts, while also discussing the latest opinions about alignment in TKA. Finally, it provides suggestions for applying consistent nomenclature to future research, especially as we explore the implications of 3D alignment patterns on patient outcomes. Cite this article:
It is unknown whether gap laxities measured in robotic arm-assisted total knee arthroplasty (TKA) correlate to load sensor measurements. The aim of this study was to determine whether symmetry of the maximum medial and lateral gaps in extension and flexion was predictive of knee balance in extension and flexion respectively using different maximum thresholds of intercompartmental load difference (ICLD) to define balance. A prospective cohort study of 165 patients undergoing functionally-aligned TKA was performed (176 TKAs). With trial components in situ, medial and lateral extension and flexion gaps were measured using robotic navigation while applying valgus and varus forces. The ICLD between medial and lateral compartments was measured in extension and flexion with the load sensor. The null hypothesis was that stressed gap symmetry would not correlate directly with sensor-defined soft tissue balance.Aims
Methods
Aims. While mechanical alignment (MA) is the traditional technique in total knee arthroplasty (TKA), its potential for altering constitutional alignment remains poorly understood. This study aimed to quantify unintentional changes to constitutional coronal alignment and joint line obliquity (JLO) resulting from MA. Methods. A retrospective cohort study was undertaken of 700 primary MA TKAs (643 patients) performed between 2014 and 2017. Lateral distal femoral and
Aims. Once knee arthritis and deformity have occurred, it is currently not known how to determine a patient’s constitutional (pre-arthritic) limb alignment. The purpose of this study was to describe and validate the arithmetic hip-knee-ankle (aHKA) algorithm as a straightforward method for preoperative planning and intraoperative restoration of the constitutional limb alignment in total knee arthroplasty (TKA). Methods. A comparative cross-sectional, radiological study was undertaken of 500 normal knees and 500 arthritic knees undergoing TKA. By definition, the aHKA algorithm subtracts the lateral distal femoral angle (LDFA) from the
Aims. An algorithm to determine the constitutional alignment of the lower limb once arthritic deformity has occurred would be of value when undertaking kinematically aligned total knee arthroplasty (TKA). The purpose of this study was to determine if the arithmetic hip-knee-ankle angle (aHKA) algorithm could estimate the constitutional alignment of the lower limb following development of significant arthritis. Methods. A matched-pairs radiological study was undertaken comparing the aHKA of an osteoarthritic knee (aHKA-OA) with the mechanical HKA of the contralateral normal knee (mHKA-N). Patients with Grade 3 or 4 Kellgren-Lawrence tibiofemoral osteoarthritis in an arthritic knee undergoing TKA and Grade 0 or 1 osteoarthritis in the contralateral normal knee were included. The aHKA algorithm subtracts the lateral distal femoral angle (LDFA) from the
Identifying and restoring alignment is a primary aim of total knee arthroplasty (TKA). In the coronal plane, the pre-pathological hip knee angle can be predicted using an arithmetic method (aHKA) by measuring the
The Coronal Plane Alignment of the Knee (CPAK) is a recent method for classifying knees using the hip-knee-ankle angle and joint line obliquity to assist surgeons in selection of an optimal alignment philosophy in total knee arthroplasty (TKA)1. It is unclear, however, how CPAK classification impacts pre-operative joint balance. Our objective was to characterise joint balance differences between CPAK categories. A retrospective review of TKA's using the OMNIBotics platform and BalanceBot (Corin, UK) using a tibia first workflow was performed. Lateral distal femoral angle (LDFA) and
Abstract. Introduction. Coronal plane alignment of the knee (CPAK) classification utilises the native arithmetic hip-knee alignment to calculate the constitutional limb alignment and joint line obliquity which is important in pre-operative planning. The objective of this study was to compare the accuracy and reproducibility of measuring the lower limb constitutional alignment with the traditional long leg radiographs versus computed tomography (CT) used for pre-operative planning in robotic-arm assisted TKA. Methods. Digital long leg radiographs and pre-operative CT scan plans of 42 patients (46 knees) with osteoarthritis undergoing robotic-arm assisted total knee replacement were analysed. The constitutional alignment was established by measuring the
The aim was to report operative complications, radiographic and patient-reported outcomes following lateral tibial plateau fracture fixation augmented with calcium phosphate cement (CPC). From 2007–2018, 187 patients (median age 57yrs [range 22–88], 63% female [n=118/187]) with a Schatzker II/III fracture were retrospectively identified. There were 103 (55%) ORIF and 84 (45%) percutaneous fixation procedures. Complications and radiographic outcomes were determined from outpatient records and radiographs. Long-term follow-up was via telephone interview. At a median of 6 months (range 0.1–138) postoperatively, complications included superficial peroneal nerve injury (0.5%, n=1/187), infection (6.4%, n=12/187), prominent metalwork (10.2%, n=19/187) and post-traumatic osteoarthritis (PTOA; 5.3%, n=10/187). The median postoperative
Objective. To analyze the short-term outcome after medial open-wedge high tibial osteotomy with a 3D-printing technology in early medial keen osteoarthritis and varus malalignment. Design and Method. 32 knees(28 cases) of mOWHTO (fixation with an angular-stable TomoFix implant(Synthes)) with a 3D-printing technology combined with arhtroscopy were prospectively surveyed with regard to functional outcome(Hospital for special knee score [HSS] score). Pre- and postoperative tibial bone varus angle (TBVA), mechanical
Introduction. Deformity influences the weight bearing stresses on the knee joint. Correction of mechanical alignment is performed to offload the knee and slow the rate of degenerative change. Fixator assisted deformity correction facilitates accurate correction prior to internal fixation. We present our results with standard Ilizarov and UNYCO system assisted deformity correction of the lower limb. Materials and Methods. Retrospective analysis of adult surgical cases of mechanical re-alignment performed between 2010 and 2019 in a tertiary referral centre. We recorded standard demographics and operative time from the electronic patient record. We analysed digitalised radiographs to record pre- and post-operative measurements of: Mechanical axis deviation (MAD), femoral
Abstract. Background. Lower limb mechanical axis has long been seen as a key to successful in lower limb surgery, including knee arthroplasty. Traditionally, coronal alignment has been assessed with weight-bearing lower limb radiographs (LLR) allowing assessment of hip-knee-ankle alignment. More recently CT scanograms (CTS) have been advocated as a possible alternative, having the potential benefits of being quicker, cheaper, requiring less specialist equipment and being non-weightbearing. Objectives. To evaluate the accuracy and comparability of lower limb alignment values derived from LLR versus CTS. Methods. We prospectively investigated patients undergoing knee arthroplasty with preoperative and postoperative LLR and CTS, analysing both preoperative and postoperative LLRs & CTS giving 140 imaging tests for direct comparison. We used two independent observers to calculate on each of imaging modalities, on both pre- and post-operative images, the: hip-knee-ankle alignment (HKA), lateral distal femoral angle (LDFA) and
Introduction. The Center for Medicare and Medicaid Services (CMS) is faced with a challenge of decreasing the cost of care for total knee arthroplasty (TKA), but must make efforts to prevent patient selection bias in the process. Currently, no appropriate modifier codes exist for primary TKA based on case complexity. We sought to determine differences in perioperative parameters for patients with “complex” primary TKA with the hypothesis that they would require increased cost of care, prolonged care times, and have worse postoperative outcome metrics. Methods. We performed a single center retrospective review from 2015 to 2018 of all primary TKA. Patient demographics,
Genu varum in the achondroplastic patient has a complex and multifactorial aetiology. There is little mention in the literature of the role of fibular overgrowth. Using the ratio of fibular to tibial length as a measurement of possible fibular overgrowth, we have related it to the development of genu varum. Full-length standing anteroposterior radiographs of 53 patients with achondroplasia were analysed. There were 30 skeletally-immature and 23 skeletally-mature patients. Regression analysis was performed in order to determine if there was a causal relationship between fibular overgrowth and the various indices of alignment of the lower limb. Analysis showed that the fibular to tibial length ratio had a significant correlation with the
The objective of this study was to compare differences in alignment following robotic arm-assisted bi-unicompartmental knee arthroplasty (Bi-UKA) and conventional total knee arthroplasty (TKA). This was a prospective, randomised controlled trial of 70 patients. 39 TKAs were implanted manually, as per standard protocol at our institution, and 31 Bi-UKA patients simultaneously received fixed-bearing medial and lateral UKAs, implanted using robotic arm-assistance. Preoperative and 3-month postoperative CT scans were analysed to determine hip knee ankle angle (HKAA), medial distal femoral angle (MDFA), and
Introduction: Optimal component position in all planes and well balanced soft tissues lead to a good clinical outcome and long-term survival after total knee arthroplasty. We investigated the implantation accuracy of navigated total knee arthroplasty at 3 months followup and the influence on the clinical outcome at 2 years followup. Patients and Methods: Forty-four patients (44 procedures) were enrolled in our prospective study. One half of the surgeries were performed using a computed tomography based navigation system, and one half of the surgeries were performed without computed tomography navigation. Outcomes were based on the Insall knee score parameters, anterior knee pain, patient satisfaction, feeling of instability, and step test. The radiographic parameters were the mechanical axis, tibial slope, lateral distal femoral
Aims. The aims of this retrospective study were to determine the incidence of extra-articular deformities (EADs), and determine their effect on postoperative alignment in knees undergoing mobile-bearing, medial unicompartmental knee arthroplasty (UKA). Patients and Methods. Limb mechanical alignment (hip-knee-ankle angle), coronal bowing of the femoral shaft and proximal tibia vara or
Anterior knee pain (AKP) is the commonest complication of total knee arthroplasty (TKA). This study aims to assess whether sagittal femoral component position is an independent predictor of AKP after cruciate retaining single radius TKA without primary patellofemoral resurfacing. From a prospective cohort of 297 consecutive TKAs, 73 (25%) patients reported AKP and 89 (30%) reported no pain at 10 years. Patients were assessed pre-operatively and at 1, 5 and 10 years using the short form 12 and Oxford Knee Score (OKS). Variables assessed included demographic data, indication, reoperation, patella resurfacing, and radiographic criteria. Patients with AKP (mean age 67.0 (38–82), 48 (66%) female) had mean Visual Analogue Scale (VAS) Pain scores of 34.3 (range 5–100). VAS scores were 0 in patients with no pain (mean age 66.5 (41–82), 60 (67%) female). Femoral component flexion (FCF), anterior femoral offset ratio, and
Objective. Open-wedge high tibial osteotomy (OWHTO) involves performing a corrective osteotomy of the proximal tibia and removing a wedge of bone to correct varus alignment. Although previous studies have investigated changes in leg length before and after OWHTO using X-rays, none has evaluated three-dimensional (3D) leg length changes after OWHTO. We therefore used 3D preoperative planning software to evaluate changes in leg length after OWHTO in three dimensions. Methods. The study subjects were 55 knees of 46 patients (10 men and 36 women of mean age 69.9 years) with medial osteoarthritis of the knee or osteonecrosis of the medial femoral condyle with a femorotibial angle of >185º and restricted range of motion (extension <–10º, flexion <130º), excluding those also suffering from patellofemoral arthritis or lateral osteoarthritis of the knee. OWHTO was simulated from computed tomography scans of the whole leg using ZedHTO 3D preoperative planning software. We analyzed the hip-knee-ankle angle (HKA), flexion contracture angle (FCA), mechanical
Introduction. Three anatomic landmarks are typically used to estimate proper femoral component rotation in total knee arthroplasty: the transepicondylar axis (TEA), Whiteside's line, and the posterior condylar axis (PCA). Previous studies have shown that the presence of tibia vara may be accompanied by a hyperplastic posteromedial femoral condyle, which affects the relationship between the PCA and the TEA. The purpose of this study was to determine the relationship of tibia vara with the PCA. Methods. Two hundred and forty-eight knees underwent planning for total knee arthroplasty with MRI. The MRI was used to characterize the relationship between the transepicondylar axis and the posterior condylar axis. Long-leg standing films (LLSF) were obtained to evaluate the
Background. Achieving optimal prosthesis alignment during total knee arthroplasty (TKA) is essential. Imageless computer-assisted surgery (CAS) is developed to improve knee prosthesis alignment and with CAS it is possible to perform intraoperative alignment measurements. Lower limb alignment measurements are also performed for preoperative planning and postoperative evaluation. A new stereoradiography system, called EOS, can be used to perform these measurements in 3D and thus measurement errors due to malpositioning can be eliminated. Since both CAS and EOS are based on 3D modeling, measurements should theoretically correlate well. Therefore, objective was to compare intraoperative CAS-TKA measurements with pre- and postoperative EOS 3D measurements. Methods. In a prospective study 56 CAS-TKAs were performed and alignment measurements were recorded two times: before bone cuts were made and after implantation of the prosthesis. Pre- and postoperative coronal alignment measurements were performed using EOS 3D. CAS measurements were compared with EOS 3D reconstructions. Measured angles were: varus/valgus (VV), mechanical lateral distal-femoral (mLDFA) and
Introduction: The knee joint in congenital longitudinal deformities of the lower extremity shows a large variety of pathological findings. Valgus deformity is found in most cases and is described as being juxta- articular. To describe the true anatomic pathology we performed a radiographic analysis of the knee joint in congenital longitudinal deformities. Patients and Method: Between 1985 and 2001 we treated 102 patients presenting with congenital longitudinal deformities. Inclusion criteria for this study were diagnoses of fibular hemimelia (FBH) and/or congenital femoral deficiency (CFD), an age between 5 and 16 years, unilateral affection and availability of long standing X-rays, whereas bilateral affection or previous operations on the lower extremities were defined as exclusion criteria. Twenty-four parameters were defined on the femur and tibia respectively and a nomenclature was created. The mean values including standard deviation were calculated and we statistically compared the parameters of the affected to those of the non-affected knee. Furthermore, MRI scans of the knee joint of 20 of these patients were evaluated. Results: Thirty- nine patients (19 female, 20 male) met the inclusion criteria. The average age at the time of evaluation was 8.87 years (3.1 SD). A combined deficiency of femur and tibia was found in 35 patients. The predominant diagnosis was CFD in 13, fibular hemime-lia in 13 and fibular aplasia in 9 cases. The anatomic lateral distal femoral angle (ALDFA) measured 75.4° (2.5 SD) on the affected, and 81.6° (1.6 SD) on the non-affected knee. The lateral distal femoral metaphyseal angle of the affected side and of the non-affected side showed no significant difference. The distal lateral femoral epiphyseal width (DLFEW) was decreased in the affected limb compared to the non affected limb, whereas the distal medial femoral epiphyseal width (DMFEW) of the affected and non-affected side showed only a minor difference. In the tibia we found no significant difference between the variables for the
With observed success and increased popularity of growth modulation techniques, there has been a trend towards use in progressively younger patients. Younger age at growth modulation increases the likelihood of complete deformity correction and need for implant removal prior to skeletal maturity introducing the risk of rebound deformity. The purpose of this study was to quantify magnitude and identify risk factors for rebound deformity after growth modulation. We performed a retrospective review of all patients undergoing growth modulation with a tension band plate for coronal plane deformity about the knee with subsequent implant removal. Exclusion criteria included completion epiphysiodesis or osteotomy at implant removal, ongoing growth modulation, and less than one year radiographic follow-up without rebound deformity. Mechanical lateral distal femoral angle (mLDFA), mechanical
Conventional total knee arthroplasty aims to place the joint line perpendicular to the mechanical axis, despite the fact that the normal knee is inclined approximately 3 degrees, resulting in a
Purpose:. Despite advances in limb reconstruction, there are still a number of young patients who require trans-tibial amputation. Amputation osteoplasty is a technique described by Ertl to enhance rehabilitation after trans-tibial amputation. The purpose of the present study was to evaluate the results of the original Ertl procedure in skeletally immature patients, and to assess whether use of this procedure would result in a diminished incidence of bony overgrowth. Methods:. Four consecutive patients (five amputations) treated between January 2005 and June 2008 were reviewed. Clinical evaluation consisted of completion of the prosthesis evaluation questionnaire (PEQ) and physical examination. Radiographic analysis was performed to evaluate bone-bridge healing, bone overgrowth and the
This study aimed to define the rates of lower limb angular correction using temporary hemiepiphysiodesis in differing skeletal pathologies. A retrospective review of 61 children (36M:25F) with angular deformities about the knee who underwent 8-plate hemiepiphysiodesis (mean age 10.8y) was undertaken. The children were divided into 9 groups based on their underlying pathology (lower limb hypoplasia, Blount's disease, skeletal dysplasia, rickets, metabolic disease, acquired growth disturbance, vascular malformation, steroid use and complex genetic disorders). Radiographic measurements of each limb segment was undertaken using the TraumaCad® digital templating software based on standing long-leg radiographs - mechanical lateral distal femoral angle (mLDFA) and mechanical
Introduction. Medial open wedge high tibial osteotomy (HTO) is a generally accepted surgical method for medial unicompartmental osteoarthritis with varus malalignment of the lower extremity. However, several authors have suggested the possibility of unintentional secondary changes during open wedge HTO, which include posterior tibial slope angle (PTS) change, tibial rotation change and medial–lateral slope change of the knee joint line, may influence knee kinematics and produce poor clinical outcomes. We sought to analyze postoperative changes in three-dimensional planes using a virtual wedge osteotomy 3D model. Pre- and post-operative changes in the
Introduction. Wear debris from polyethylene tibial inserts has been associated with limited longevity of total knee replacements (TKRs). While material factors were studied extensively and considerable progress has been made, there is little knowledge about surgical factors, particularly on how the wear rate is related to implant positioning. It was the purpose of this study to determine the combined effect of patient and implant positioning factors on the volumetric wear rate of TKRs. Our hypothesis was that implant alignment has a significant impact on the wear rate when controlled for other patient factors. Methods. This study included 59 tibial inserts of a cruciate retaining TKR design (Nexgen, Zimmer Inc.). The patients' age, sex, weight, height, and implant size were obtained. All implants were scanned with a coordinate measuring machine. Volumetric wear was determined using an autonomous mathematical reconstruction method (Figure 1). Radiographs were used to determine the anatomic lateral distal femoral angle (aLDFA), anatomic
Introduction. Neutral mechanical alignment in TKA has been shown to be an important consideration for survivorship, wear, and aseptic loosening. However, native knee anatomy is described by a joint line in 3° of varus, 2–3° of mechanical distal femoral valgus, and 2–3° of proximal tibia varus. Described kinematic planning methods replicate native joint alignment in extension without changing tibiofemoral alignment, but do not account for native alignment through a range of motion. An asymmetric TKA femoral component with a thicker medial femoral condyle and posterior condylar internal rotation paired with an asymmetric polyethylene insert aligns the joint line in 3° of varus while maintaining distal femoral and proximal tibial cuts perpendicular to mechanical axis. The asymmetric components recreate an anatomic varus joint line while avoiding tibiofemoral malalignment or femoral component internal rotation, a risk factor for patellofemoral maltracking. The study seeks to determine how many patients would be candidates for a kinematically planned knee without violating the principle of a neutral mechanical axis (0° ± 3°). Methods. A cohort comprised of 55 consecutive preoperative THA patients with asymptomatic knees and 55 consecutive preoperative primary unilateral TKA patients underwent simultaneous biplanar radiographic imaging. Full length coronal images from the thoracolumbar junction to the ankles were measured by two independent observers for the following: mechanical tibiofemoral angle (mTFA), mechanical lateral distal femoral angle (mLDFA), and mechanical
To evaluate the operative treatment of Blount disease using the TSF external fixator and to evaluate the system. During January 2004 and August 2008, 8 males and 2 females with Blount disease (16 limbs) were treated using TSF system. For the radiological assessment we obtained standard long-leg standing radiographs and we measured the anatomic
Purpose of the study: To find predictors for the clinical outcome in patients who underwent a high tibial osteotomy [HTO]. Method: Between 1984 and 1996 in 155 patients with genu varum a high tibial valgus osteotomy was performed. 133 HTOs were available for follow up at an average post-op time of 9.3 years (3,0 y). The morphology of the knee was evaluated by radiological (Kellgren) and arthroscopical classifications (Outerbridge). Survival time of HTO was estimated using Kaplan-Meier survivorship analysis. Patients outcome was evaluated using the WOMAC score. For statistical analysis Log-rank test and Wilcoxon-Mann Whitney U-Test were used. Results: During follow up time 19.8% of patients needed a total knee arthroplasty. Survival rate of HTO was 95% after 5 years and 77% after 10 years. In the medial compartment of knee joints with a preoperative Outerbridge stage III/IV or Kellgren stage III/IV the survival rate of HTO was significantly lower when compared to stages I/II (p<
0,05). Age, sex, dimension of the mechanical
Aims: The aim of this paper was to evaluate the position of the endoprosthesis after standard and navigated insertion in both sagittal and frontal planes. Methods: From October 2000 to March 2002, 90 Search Evolution TKR were performed in 65 females and 25 males with mean age 68 years because of primary or post-traumatic osteoarthritis. Every third patient received this endoprosthesis without use of navigation. The study sample was so divided into two groups. The þrst group was constituted of 60 patients with TKRs inserted with use of navigation. The second group was formed by 30 patients with TKRs inserted with standard manner. All results were statistically analyzed. Results: The mean lateral tibiofemoral angle was in the 1st group 174,3¡ and in the 2nd group 174,9¡, the mean lateral distal femoral angle was in the 1st group 83,5¡ and in the 2nd group 83,7¡, the mean
Summary Statement. The implantation of scaffold-free CTE from suspension culture into growth-plate defects resulted in a significant reduction in growth arrest of the rabbit tibia. Introduction. In childhood and adolescence, the growth plate injury can cause partial premature arrest of growth plate, which can make problems such as leg length discrepancy and angular deformity. Bone bridge resection and variable implantation materials such as fat, bone wax, silastic and craniopalst has been investigated. However, those procedures may show limitations including the control of bone growth and long term safety of implant materials in vivo. As an alternative, homogeneous or heterogeneous cartilage cells and stem cell transplants have been tried. In this method, scaffold for cell transplantation is needed. But, so far the most suitable scaffold has not been established. Recently, some authors generated a cartilage tissue equivalent (CTE) using a suspension culture with biophysical properties similar to native hyaline cartilage. Therefore we are able to transplant the CTE without scaffold to the physeal defect. The purpose of this study was to investigated the effects of a transplantation of a vitro-generated scaffold-free tissue-engineered cartilage tissue equivalent (CTE) using a suspension chondrocyte culture in a rabbit growth arrest model. Material and Method. Cartilage tissue equivalent culture. The CTE was generated by the suspension culture of chondrocytes (2 × 10. 7. /well/1 mL) which was isolated from articular cartilage of 5 weeks New Zealand white rabbit on a 24-well plate (2.4 cm. 2. /well) treated with poly HEMA (nunc, Roskide, Denmark) for up to 8 and 16 weeks. (2)Partial growth arrest animal model. An experimental model for growth arrest was created by excising the growth plate at the proximal medial side of tibia with the 4 mm in diameter and 4 mm in depth from 6-week-old New Zealand white rabbits. Two experimental groups were set to evaluate CTE implantation; group I, no implantation as controls; group II, implantation of CTE. (3) Evaluation of effect of the transplantation of CTE. Serial plain radiographs were performed at one week. The
The impact of a diaphyseal femoral deformity on knee alignment varies according to its severity and localization. The aims of this study were to determine a method of assessing the impact of diaphyseal femoral deformities on knee alignment for the varus knee, and to evaluate the reliability and the reproducibility of this method in a large cohort of osteoarthritic patients. All patients who underwent a knee arthroplasty from 2019 to 2021 were included. Exclusion criteria were genu valgus, flexion contracture (> 5°), previous femoral osteotomy or fracture, total hip arthroplasty, and femoral rotational disorder. A total of 205 patients met the inclusion criteria. The mean age was 62.2 years (SD 8.4). The mean BMI was 33.1 kg/m2 (SD 5.5). The radiological measurements were performed twice by two independent reviewers, and included hip knee ankle (HKA) angle, mechanical medial distal femoral angle (mMDFA), anatomical medial distal femoral angle (aMDFA), femoral neck shaft angle (NSA), femoral bowing angle (FBow), the distance between the knee centre and the top of the FBow (DK), and the angle representing the FBow impact on the knee (C’KS angle).Aims
Methods
Background. Computer-assisted navigation systems for total knee arthroplasty (TKA) were introduced to improve implantation accuracy and to optimize ligament balancing. Several comparative studies in the literature confirmed an effect on the component position and other studies could not confirm these results. For ligament balancing most studies found no significant influence on the clinical outcome using a navigation system for TKA. In the literature there were no reports of mid-term results after navigated TKA. With our study we wanted to show if the use of a navigation system for TKA will have an influence on the component's position and on the clinical results at 5-year follow up. Methods. We enrolled 200 patients in a prospective randomized study with a minimum follow up of 5 years. 100 TKA were operated on without using a navigation system (Group A) and 100 surgeries (Group B) were done with computer assistance. Radiological investigation by standard radiographs including a long-leg X-ray was performed with a follow up rate in Group A of 86.2% versus 80.2% in Group B. We measured the mechanical axis of the leg, lateral distal femoral angel (LDFA),
The aims of this study were: 1) to describe extended restricted kinematic alignment (E-rKA), a novel alignment strategy during robotic-assisted total knee arthroplasty (RA-TKA); 2) to compare residual medial compartment tightness following virtual surgical planning during RA-TKA using mechanical alignment (MA) and E-rKA, in the same set of osteoarthritic varus knees; 3) to assess the requirement of soft-tissue releases during RA-TKA using E-rKA; and 4) to compare the accuracy of surgical plan execution between knees managed with adjustments in component positioning alone, and those which require additional soft-tissue releases. Patients who underwent RA-TKA between January and December 2022 for primary varus osteoarthritis were included. Safe boundaries for E-rKA were defined. Residual medial compartment tightness was compared following virtual surgical planning using E-rKA and MA, in the same set of knees. Soft-tissue releases were documented. Errors in postoperative alignment in relation to planned alignment were compared between patients who did (group A) and did not (group B) require soft-tissue releases.Aims
Methods
The aim of this study was to investigate the distribution of phenotypes in Asian patients with end-stage osteoarthritis (OA) and assess whether the phenotype affected the clinical outcome and survival of mechanically aligned total knee arthroplasty (TKA). We also compared the survival of the group in which the phenotype unintentionally remained unchanged with those in which it was corrected to neutral. The study involved 945 TKAs, which were performed in 641 patients with primary OA, between January 2000 and January 2009. These were classified into 12 phenotypes based on the combined assessment of four categories of the arithmetic hip-knee-ankle angle and three categories of actual joint line obliquity. The rates of survival were analyzed using Kaplan-Meier methods and the log-rank test. The Hospital for Special Surgery score and survival of each phenotype were compared with those of the reference phenotype with neutral alignment and a parallel joint line. We also compared long-term survival between the unchanged phenotype group and the corrected to neutral alignment-parallel joint line group in patients with Type IV-b (mild to moderate varus alignment-parallel joint line) phenotype.Aims
Methods
The aim of this study was to evaluate whether achieving medial joint opening, as measured by the change in the joint line convergence angle (∆JLCA), is a better predictor of clinical outcomes after high tibial osteotomy (HTO) compared with the mechanical axis deviation, and to find individualized targets for the redistribution of load that reflect bony alignment, joint laxity, and surgical technique. This retrospective study analyzed 121 knees in 101 patients. Patient-reported outcome measures (PROMs) were collected preoperatively and one year postoperatively, and were analyzed according to the surgical technique (opening or closing wedge), postoperative mechanical axis deviation (deviations above and below 10% from the target), and achievement of medial joint opening (∆JLCA > 1°). Radiological parameters, including JLCA, mechanical axis deviation, and the difference in JLCA between preoperative standing and supine radiographs (JLCAPD), an indicator of medial soft-tissue laxity, were measured. Cut-off points for parameters related to achieving medial joint opening were calculated from receiver operating characteristic (ROC) curves.Aims
Methods
This study aims to determine the rate of and risk factors for total knee arthroplasty (TKA) after operative management of tibial plateau fractures (TPFs) in older adults. This is a retrospective cohort study of 182 displaced TPFs in 180 patients aged ≥ 60 years, over a 12-year period with a minimum follow-up of one year. The mean age was 70.7 years (SD 7.7; 60 to 89), and 139/180 patients (77.2%) were female. Radiological assessment consisted of fracture classification; pre-existing knee osteoarthritis (OA); reduction quality; loss of reduction; and post-traumatic OA. Fracture depression was measured on CT, and the volume of defect estimated as half an oblate spheroid. Operative management, complications, reoperations, and mortality were recorded.Aims
Methods
The mid-term results of kinematic alignment (KA) for total knee arthroplasty (TKA) using image derived instrumentation (IDI) have not been reported in detail, and questions remain regarding ligamentous stability and revisions. This paper aims to address the following: 1) what is the distribution of alignment of KA TKAs using IDI; 2) is a TKA alignment category associated with increased risk of failure or poor patient outcomes; 3) does extending limb alignment lead to changes in soft-tissue laxity; and 4) what is the five-year survivorship and outcomes of KA TKA using IDI? A prospective, multicentre, trial enrolled 100 patients undergoing KA TKA using IDI, with follow-up to five years. Alignment measures were conducted pre- and postoperatively to assess constitutional alignment and final implant position. Patient-reported outcome measures (PROMs) of pain and function were also included. The Australian Orthopaedic Association National Joint Arthroplasty Registry was used to assess survivorship.Aims
Methods
The June 2024 Children’s orthopaedics Roundup360 looks at: Proximal femoral unicameral bone cysts: is ESIN the answer?; Hybrid-mesh casts in the conservative management of paediatric supracondylar humeral fractures: a randomized controlled trial; Rate and risk factors for contralateral slippage in adolescents treated for slipped capital femoral epiphysis; CRP predicts the need to escalate care after initial debridement for musculoskeletal infection; Genu valgum in paediatric patients presenting with patellofemoral instability; Nusinersen therapy changed the natural course of spinal muscular atrophy type 1: what about spine and hip?; The necessity of ulnar nerve exploration and translocation in open reduction of medial humeral epicondyle fractures in children.
Advanced 3D imaging and CT-based navigation have emerged as valuable tools to use in total knee arthroplasty (TKA), for both preoperative planning and the intraoperative execution of different philosophies of alignment. Preoperative planning using CT-based 3D imaging enables more accurate prediction of the size of components, enhancing surgical workflow and optimizing the precision of the positioning of components. Surgeons can assess alignment, osteophytes, and arthritic changes better. These scans provide improved insights into the patellofemoral joint and facilitate tibial sizing and the evaluation of implant-bone contact area in cementless TKA. Preoperative CT imaging is also required for the development of patient-specific instrumentation cutting guides, aiming to reduce intraoperative blood loss and improve the surgical technique in complex cases. Intraoperative CT-based navigation and haptic guidance facilitates precise execution of the preoperative plan, aiming for optimal positioning of the components and accurate alignment, as determined by the surgeon’s philosophy. It also helps reduce iatrogenic injury to the periarticular soft-tissue structures with subsequent reduction in the local and systemic inflammatory response, enhancing early outcomes. Despite the increased costs and radiation exposure associated with CT-based navigation, these many benefits have facilitated the adoption of imaged based robotic surgery into routine practice. Further research on ultra-low-dose CT scans and exploration of the possible translation of the use of 3D imaging into improved clinical outcomes are required to justify its broader implementation. Cite this article:
The December 2023 Knee Roundup360 looks at: Obesity is associated with greater improvement in patient-reported outcomes following primary total knee arthroplasty; Does mild flexion of the femoral prosthesis in total knee arthroplasty result in better early postoperative outcomes?; Robotic or manual total knee arthroplasty: a randomized controlled trial; Patient-relevant outcomes following first revision total knee arthroplasty, by diagnosis: an analysis of implant survivorship, mortality, serious medical complications, and patient-reported outcome measures using the National Joint Registry data set; Sagittal alignment in total knee arthroplasty: are there any discrepancies between robotic-assisted and manual axis orientation?; Tourniquet use does not impact recovery trajectory in total knee arthroplasty; Impact of proximal tibial varus anatomy on survivorship after medial unicondylar knee arthroplasty; Bone cement directly to the implant in primary total knee arthroplasty?; Maintaining joint line obliquity optimizes outcomes in patients with constitutionally varus knees.
Robotic arm-assisted surgery offers accurate and reproducible guidance in component positioning and assessment of soft-tissue tensioning during knee arthroplasty, but the feasibility and early outcomes when using this technology for revision surgery remain unknown. The objective of this study was to compare the outcomes of robotic arm-assisted revision of unicompartmental knee arthroplasty (UKA) to total knee arthroplasty (TKA) versus primary robotic arm-assisted TKA at short-term follow-up. This prospective study included 16 patients undergoing robotic arm-assisted revision of UKA to TKA versus 35 matched patients receiving robotic arm-assisted primary TKA. In all study patients, the following data were recorded: operating time, polyethylene liner size, change in haemoglobin concentration (g/dl), length of inpatient stay, postoperative complications, and hip-knee-ankle (HKA) alignment. All procedures were performed using the principles of functional alignment. At most recent follow-up, range of motion (ROM), Forgotten Joint Score (FJS), and Oxford Knee Score (OKS) were collected. Mean follow-up time was 21 months (6 to 36).Aims
Methods
As an alternative to external fixators, intramedullary lengthening nails (ILNs) can be employed for distraction osteogenesis. While previous studies have demonstrated that typical complications of external devices, such as soft-tissue tethering, and pin site infection can be avoided with ILNs, there is a lack of studies that exclusively investigated tibial distraction osteogenesis with motorized ILNs inserted via an antegrade approach. A total of 58 patients (median age 17 years (interquartile range (IQR) 15 to 21)) treated by unilateral tibial distraction osteogenesis for a median leg length discrepancy of 41 mm (IQR 34 to 53), and nine patients with disproportionate short stature treated by bilateral simultaneous tibial distraction osteogenesis, with magnetically controlled motorized ILNs inserted via an antegrade approach, were retrospectively analyzed. The median follow-up was 37 months (IQR 30 to 51). Outcome measurements were accuracy, precision, reliability, bone healing, complications, and patient-reported outcome assessed by the Limb Deformity-Scoliosis Research Society Score (LD-SRS-30).Aims
Methods
Patient dissatisfaction following primary total knee arthroplasty (TKA) with manual jig-based instruments has been reported to be as high as 30%. Robotic-assisted total knee arthroplasty (RA-TKA) has been increasingly used in an effort to improve patient outcomes, however there is a paucity of literature examining patient satisfaction after RA-TKA. This study aims to identify the incidence of patients who were not satisfied following RA-TKA and to determine factors associated with higher levels of dissatisfaction. This was a retrospective review of 674 patients who underwent primary TKA between October 2016 and September 2020 with a minimum two-year follow-up. A five-point Likert satisfaction score was used to place patients into two groups: Group A were those who were very dissatisfied, dissatisfied, or neutral (Likert score 1 to 3) and Group B were those who were satisfied or very satisfied (Likert score 4 to 5). Patient demographic data, as well as preoperative and postoperative patient-reported outcome measures, were compared between groups.Aims
Methods
The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA
To determine the relationship between articular cartilage status and clinical outcomes after medial opening-wedge high tibial osteotomy (MOHTO) for medial compartmental knee osteoarthritis at intermediate follow-up. We reviewed 155 patients (155 knees) who underwent MOHTO from January 2008 to December 2016 followed by second-look arthroscopy with a mean 5.3-year follow-up (2.0 to 11.7). Arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system. Patients were divided into two groups based on the presence of normal or nearly normal quality cartilage in the medial femoral condyle: good (second-look arthroscopic) status (ICRS grade I or II; n = 70), and poor (second-look arthroscopic) status (ICRS grade III or IV; n = 85) groups at the time of second-look arthroscopy. Clinical outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-Item Short Form survey.Aims
Methods
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). 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.Aims
Methods
Background:. It has been suggested that double-level osteotomy can prevent the occurrence of joint line obliquity (JLO), as one of the complications following high tibial osteotomy (HTO). In this study, we aimed to compare the preoperative distal femoral and proximal tibial obliquity in patients with primary genu varum with a group of normal subjects (without genu varum). Materials and methods:. 75 patients with primary genu varum and 75 normal persons, contributed to a case-control study. The medial distal femoral mechanical
Eight-plates are used to correct varus-valgus deformity (VVD) or limb-length discrepancy (LLD) in children and adolescents. It was reported that these implants might create a bony deformity within the knee joint by change of the roof angle (RA) after epiphysiodesis of the proximal tibia following a radiological assessment limited to anteroposterior (AP) radiographs. The aim of this study was to analyze the RA, complemented with lateral knee radiographs, with focus on the tibial slope (TS) and the degree of deformity correction. A retrospective, single-centre study was conducted. The treatment group (n = 64 knees in 44 patients) was subclassified according to the implant location in two groups: 1) medial hemiepiphysiodesis; and 2) lateral hemiepiphysiodesis. A third control group consisted of 25 untreated knees. The limb axes and RA were measured on long standing AP leg radiographs. Lateral radiographs of 40 knees were available for TS analysis. The mean age of the patients was 10.6 years (4 to 15) in the treatment group and 8.4 years (4 to 14) in the control group. Implants were removed after a mean 1.2 years (0.5 to 3).Aims
Methods
The goal of the current systematic review was to assess the impact of implant placement accuracy on outcomes following total knee arthroplasty (TKA). A systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines using the Ovid Medline, Embase, Cochrane Central, and Web of Science databases in order to assess the impact of the patient-reported outcomes measures (PROMs) and implant placement accuracy on outcomes following TKA. Studies assessing the impact of implant alignment, rotation, size, overhang, or condylar offset were included. Study quality was assessed, evidence was graded (one-star: no evidence, two-star: limited evidence, three-star: moderate evidence, four-star: strong evidence), and recommendations were made based on the available evidence.Aims
Methods
Porous metaphyseal cones can be used for fixation in revision total knee arthroplasty (rTKA) and complex TKAs. This metaphyseal fixation has led to some surgeons using shorter cemented stems instead of diaphyseal engaging cementless stems with a potential benefit of ease of obtaining proper alignment without being beholden to the diaphysis. The purpose of this study was to evaluate short term clinical and radiographic outcomes of a series of TKA cases performed using 3D-printed metaphyseal cones. A retrospective review of 86 rTKAs and nine complex primary TKAs, with an average age of 63.2 years (SD 8.2) and BMI of 34.0 kg/m2 (SD 8.7), in which metaphyseal cones were used for both femoral and tibial fixation were compared for their knee alignment based on the type of stem used. Overall, 22 knees had cementless stems on both sides, 52 had cemented stems on both sides, and 15 had mixed stems. Postoperative long-standing radiographs were evaluated for coronal and sagittal plane alignment. Adjusted logistic regression models were run to assess malalignment hip-knee-ankle (HKA) alignment beyond ± 3° and sagittal alignment of the tibial and femoral components ± 3° by stem type.Aims
Methods
It is unknown whether kinematic alignment (KA) objectively improves knee balance in total knee arthroplasty (TKA), despite this being the biomechanical rationale for its use. This study aimed to determine whether restoring the constitutional alignment using a restrictive KA protocol resulted in better quantitative knee balance than mechanical alignment (MA). We conducted a randomized superiority trial comparing patients undergoing TKA assigned to KA within a restrictive safe zone or MA. Optimal knee balance was defined as an intercompartmental pressure difference (ICPD) of 15 psi or less using a pressure sensor. The primary endpoint was the mean intraoperative ICPD at 10° of flexion prior to knee balancing. Secondary outcomes included balance at 45° and 90°, requirements for balancing procedures, and presence of tibiofemoral lift-off.Aims
Methods
The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery. An analysis of 38 patients who underwent TKA and 32 who underwent bi-UKA was performed as a secondary study from a prospective, single-centre, randomized controlled trial. CT imaging was used to measure coronal, sagittal, and axial alignment of the knee preoperatively and at three months postoperatively to determine changes in anatomy that had occurred as a result of the surgery. The hip-knee-ankle angle (HKAA) was also measured to identify any differences between the two groups.Aims
Methods
Patient-specific instrumentation of total knee arthroplasty (TKA) is a technique permitting the targeting of individual kinematic alignment, but deviation from a neutral mechanical axis may have implications on implant fixation and therefore survivorship. The primary objective of this randomized controlled study was to compare the fixation of tibial components implanted with patient-specific instrumentation targeting kinematic alignment (KA+PSI) A total of 47 patients due to undergo TKA were randomized to KA+PSI (n = 24) or MA+CAS (n = 23). In the KA+PSI group, there were 16 female and eight male patients with a mean age of 64 years (Aims
Patients and Methods
Although bone cement is the primary mode of fixation in total knee arthroplasty (TKA), cementless fixation is gaining interest as it has the potential of achieving lasting biological fixation. By 3D printing an implant, highly porous structures can be manufactured, promoting osseointegration into the implant to prevent aseptic loosening. This study compares the migration of cementless, 3D-printed TKA to cemented TKA of a similar design up to two years of follow-up using radiostereometric analysis (RSA) known for its ability to predict aseptic loosening. A total of 72 patients were randomized to either cementless 3D-printed or a cemented cruciate retaining TKA. RSA and clinical scores were evaluated at baseline and postoperatively at three, 12, and 24 months. A mixed model was used to analyze the repeated measurements.Aims
Methods
The results of kinematic total knee arthroplasty (KTKA) have been reported in terms of limb and component alignment parameters but not in terms of gap laxities and differentials. In kinematic alignment (KA), balance should reflect the asymmetrical balance of the normal knee, not the classic rectangular flexion and extension gaps sought with gap-balanced mechanical axis total knee arthroplasty (MATKA). This paper aims to address the following questions: 1) what factors determine coronal joint congruence as measured on standing radiographs?; 2) is flexion gap asymmetry produced with KA?; 3) does lateral flexion gap laxity affect outcomes?; 4) is lateral flexion gap laxity associated with lateral extension gap laxity?; and 5) can consistent ligament balance be produced without releases? A total of 192 KTKAs completed by a single surgeon using a computer-assisted technique were followed for a mean of 3.5 years (2 to 5). There were 116 male patients (60%) and 76 female patients (40%) with a mean age of 65 years (48 to 88). Outcome measures included intraoperative gap laxity measurements and component positions, as well as joint angles from postoperative three-foot standing radiographs. Patient-reported outcome measures (PROMs) were analyzed in terms of alignment and balance: EuroQol (EQ)-5D visual analogue scale (VAS), Knee Injury and Osteoarthritis Outcome Score (KOOS), KOOS Joint Replacement (JR), and Oxford Knee Score (OKS).Aims
Patients and Methods
Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved. Cite this article:
Unicompartmental knee arthroplasty (UKA) is an alternative to total knee arthroplasty for patients who require treatment of single-compartment osteoarthritis, especially for young patients. To satisfy this requirement, new patient-specific prosthetic designs have been introduced. The patient-specific UKA is designed on the basis of data from preoperative medical images. In general, knee implant design with increased conformity has been developed to provide lower contact stress and reduced wear on the tibial insert compared with flat knee designs. The different tibiofemoral conformity may provide designers the opportunity to address both wear and kinematic design goals simultaneously. The aim of this study was to evaluate wear prediction with respect to tibiofemoral conformity design in patient-specific UKA under gait loading conditions by using a previously validated computational wear method. Three designs with different conformities were developed with the same femoral component: a flat design normally used in fixed-bearing UKA, a tibia plateau anatomy mimetic (AM) design, and an increased conforming design. We investigated the kinematics, contact stress, contact area, wear rate, and volumetric wear of the three different tibial insert designs.Objectives
Methods
We aimed to investigate factors related to the technique of medial
opening wedge high tibial osteotomy which might predispose to the
development of a lateral hinge fracture. A total of 71 patients with 82 osteotomies were included in the
study. Their mean age was 62.9 years (37 to 80). The classification
of the type of osteotomy was based on whether it extended beyond
the fibular head. The level of the osteotomy was classified according
to the height of its endpoint.Aims
Patients and Methods
The role of high tibial osteotomy (HTO) is being questioned by
the use of unicompartmental knee arthroplasty (UKA) in the treatment
of medial compartment femorotibial osteoarthritis. Our aim was to
compare the outcomes of revision HTO or UKA to a total knee arthroplasty
(TKA) using computer-assisted surgery in matched groups of patients. We conducted a retrospective study to compare the clinical and
radiological outcome of patients who underwent revision of a HTO
to a TKA (group 1) with those who underwent revision of a medial
UKA to a TKA (group 2). All revision procedures were performed using
computer-assisted surgery. We extracted these groups of patients
from our database. They were matched by age, gender, body mass index,
follow-up and pre-operative functional score. The outcomes included
the Knee Society Scores (KSS), radiological outcomes and the rate
of further revision.Aims
Patients and Methods
Patient-specific (PS) implantation surgical technology has been introduced in recent years and a gradual increase in the associated number of surgical cases has been observed. PS technology uses a patient’s own geometry in designing a medical device to provide minimal bone resection with improvement in the prosthetic bone coverage. However, whether PS unicompartmental knee arthroplasty (UKA) provides a better biomechanical effect than standard off-the-shelf prostheses for UKA has not yet been determined, and still remains controversial in both biomechanical and clinical fields. Therefore, the aim of this study was to compare the biomechanical effect between PS and standard off-the-shelf prostheses for UKA. The contact stresses on the polyethylene (PE) insert, articular cartilage and lateral meniscus were evaluated in PS and standard off-the-shelf prostheses for UKA using a validated finite element model. Gait cycle loading was applied to evaluate the biomechanical effect in the PS and standard UKAs.Objectives
Methods
Open wedge high tibial osteotomy (OWHTO) for medial-compartment
osteoarthritis of the knee can be complicated by intra-operative
lateral hinge fracture (LHF). We aimed to establish the relationship
between hinge position and fracture types, and suggest an appropriate
hinge position to reduce the risk of this complication. Consecutive patients undergoing OWHTO were evaluated on coronal
multiplanar reconstruction CT images. Hinge positions were divided
into five zones in our new classification, by their relationship
to the proximal tibiofibular joint (PTFJ). Fractures were classified
into types I, II, and III according to the Takeuchi classification.Aims
Patients and Methods
The aim of this study was to evaluate the risk
factors for dislocation of the bearing after a mobile-bearing Oxford medial
unicompartmental knee replacement (UKR) and to test the hypothesis
that surgical factors, as measured from post-operative radiographs,
are associated with its dislocation From a total of 480 UKRs performed between 2001 and 2012, in
391 patients with a mean age of 66.5 years (45 to 82) (316 female,
75 male), we identified 17 UKRs where bearing dislocation occurred.
The post-operative radiological measurements of the 17 UKRs and
51 matched controls were analysed using conditional logistic regression analysis.
The post-operative radiological measurements included post-operative
change in limb alignment, the position of the femoral and tibial
components, the resection depth of the proximal tibia, and the femoral component-posterior
condyle classification. We concluded that a post-operative decrease in the posterior
tibial slope relative to the pre-operative value was the only significant
determinant of dislocation of the bearing after medial Oxford UKR
(odds ratio 1.881; 95% confidence interval 1.272 to 2.779). A post-operative
posterior tibial slope <
8.45° and a difference between the pre-operative
and post-operative posterior tibial slope of >
2.19° may increase
the risk of dislocation. Cite this article:
The purpose of this study was to compare the results and complications of tibial lengthening over an intramedullary nail with treatment using the traditional Ilizarov method. In this matched case study, 16 adult patients underwent 19 tibial lengthening over nails (LON) procedures. For the matched case group, 17 patients who underwent 19 Ilizarov tibial lengthenings were retrospectively matched to the LON group.Objectives
Methods
To present our experience of using a combination of intra-articular
osteotomy and external fixation to treat different deformities of
the knee. A total of six patients with a mean age of 26.5 years (15 to
50) with an abnormal hemi-joint line convergence angle (HJLCA) and
mechanical axis deviation (MAD) were included. Elevation of a tibial
hemiplateau or femoral condylar advancement was performed and limb
lengthening with correction of residual deformity using a circular
or monolateral Ilizarov frame.Aims
Patients and Methods
We present the results of the surgical correction of lower-limb deformities caused by metabolic bone disease. Our series consisted of 17 patients with a diagnosis of hypophosphataemic rickets and two with renal osteodystrophy; their mean age was 25.6 years (14 to 57). In all, 43 lower-limb segments (27 femora and 16 tibiae) were osteotomised and the deformity corrected using a monolateral external fixator. The segment was then stabilised with locked intramedullary nailing. In addition, six femora in three patients were subsequently lengthened by distraction osteogenesis. The mean follow-up was 60 months (18 to 120). The frontal alignment parameters (the mechanical axis deviation, the lateral distal femoral angle and the medial proximal tibial angle) and the sagittal alignment parameters (the posterior distal femoral angle and the posterior proximal tibial angle) improved post-operatively. The external fixator was removed either at the end of surgery or at the end of the lengthening period, allowing for early mobilisation and weight-bearing. We encountered five problems and four obstacles in the programme of treatment. The use of intramedullary nails prevented recurrence of deformity and refracture.
Mechanical alignment has been a fundamental tenet of total knee arthroplasty (TKA) since modern knee replacement surgery was developed in the 1970s. The objective of mechanical alignment was to infer the greatest biomechanical advantage to the implant to prevent early loosening and failure. Over the last 40 years a great deal of innovation in TKA technology has been focusing on how to more accurately achieve mechanical alignment. Recently the concept of mechanical alignment has been challenged, and other alignment philosophies are being explored with the intention of trying to improve patient outcomes following TKA. This article examines the evolution of the mechanical alignment concept and whether there are any viable alternatives.
Our aim was to investigate the predictive factors for the development
of a rebound phenomenon after temporary hemiepiphysiodesis in children
with genu valgum. We studied 37 limbs with idiopathic genu valgum who were treated
with hemiepiphyseal stapling, and with more than six months remaining
growth at removal of the staples. All children were followed until
skeletal maturity or for more than two years after removal of the
staples.Aims
Patients and Methods
We wished to examine the effectiveness of tibial lengthening
using a two ring Ilizarov frame in skeletally immature patients.
This is a potentially biomechanically unstable construct which risks
the loss of axial control. We retrospectively reviewed a consecutive series of 24 boys and
26 girls, with a mean age of 8.6 years (4 to 14), who underwent
52 tibial lengthening procedures with a mean follow-up of 4.3 years
(4.0 to 16.9). Tibial alignment was measured before and after treatment
using joint orientation lines from the knee and a calculation of
the oblique plane axis.Aims
Patients and Methods
Patient-specific cutting guides (PSCGs) are designed
to improve the accuracy of alignment of total knee replacement (TKR).
We compared the accuracy of limb alignment and component positioning
after TKR performed using PSCGs or conventional instrumentation.
A total of 80 patients were randomised to undergo TKR with either of
the different forms of instrumentation, and radiological outcomes
and peri-operative factors such as operating time were assessed.
No significant difference was observed between the groups in terms
of tibiofemoral angle or femoral component alignment. Although the
tibial component in the PSCGs group was measurably closer to neutral
alignment than in the conventional group, the size of the difference
was very small (89.8° ( Cite this article:
As many as 25% to 40% of unicompartmental knee
replacement (UKR) revisions are performed for pain, a possible cause
of which is proximal tibial strain. The aim of this study was to
examine the effect of UKR implant design and material on cortical
and cancellous proximal tibial strain in a synthetic bone model.
Composite Sawbone tibiae were implanted with cemented UKR components
of different designs, either all-polyethylene or metal-backed. The tibiae
were subsequently loaded in 500 N increments to 2500 N, unloading
between increments. Cortical surface strain was measured using a
digital image correlation technique. Cancellous damage was measured
using acoustic emission, an engineering technique that detects sonic
waves (‘hits’) produced when damage occurs in material. Anteromedial cortical surface strain showed significant differences
between implants at 1500 N and 2500 N in the proximal 10 mm only
(p <
0.001), with relative strain shielding in metal-backed implants.
Acoustic emission showed significant differences in cancellous bone
damage between implants at all loads (p = 0.001). All-polyethylene implants
displayed 16.6 times the total number of cumulative acoustic emission
hits as controls. All-polyethylene implants also displayed more
hits than controls at all loads (p <
0.001), more than metal-backed
implants at loads ≥ 1500 N (p <
0.001), and greater acoustic
emission activity on unloading than controls (p = 0.01), reflecting
a lack of implant stiffness. All-polyethylene implants were associated
with a significant increase in damage at the microscopic level compared
with metal-backed implants, even at low loads. All-polyethylene
implants should be used with caution in patients who are likely
to impose large loads across their knee joint. Cite this article:
The traditional techniques involving an oblique
tunnel or triangular wedge resection to approach a central or mixed-type
physeal bar are hindered by poor visualisation of the bar. This
may be overcome by a complete transverse osteotomy at the metaphysis
near the growth plate or a direct vertical approach to the bar.
Ilizarov external fixation using small wires allows firm fixation
of the short physis-bearing fragment, and can also correct an associated angular
deformity and permit limb lengthening. We accurately approached and successfully excised ten central-
or mixed-type bars; six in the distal femur, two in the proximal
tibia and two in the distal tibia, without damaging the uninvolved
physis, and corrected the associated angular deformity and leg-length
discrepancy. Callus formation was slightly delayed because of periosteal
elevation and stretching during resection of the bar. The resultant
resection of the bar was satisfactory in seven patients and fair
in three as assessed using a by a modified Williamson–Staheli classification. Cite this article:
We report the results of using a combination of fixator-assisted nailing with lengthening over an intramedullary nail in patients with tibial deformity and shortening. Between 1997 and 2007, 13 tibiae in nine patients with a mean age of 25.4 years (17 to 34) were treated with a unilateral external fixator for acute correction of deformity, followed by lengthening over an intramedullary nail with a circular external fixator applied at the same operating session. At the end of the distraction period locking screws were inserted through the intramedullary nail and the external fixator was removed. The mean amount of lengthening was 5.9 cm (2 to 8). The mean time of external fixation was 90 days (38 to 265). The mean external fixation index was 15.8 days/cm (8.9 to 33.1) and the mean bone healing index was 38 days/cm (30 to 60). One patient developed an equinus deformity which responded to stretching and bracing. Another developed a drop foot due to a compartment syndrome, which was treated by fasciotomy. It recovered in three months. Two patients required bone grafting for poor callus formation. We conclude that the combination of fixator-assisted nailing with lengthening over an intramedullary nail can reduce the overall external fixation time and prevent fractures and deformity of the regenerated bone.
The objective of this study was to validate the
efficacy of Takeuchi classification for lateral hinge fractures
(LHFs) in open wedge high tibial osteotomy (OWHTO). In all 74 osteoarthritic
knees (58 females, 16 males; mean age 62.9 years, standard deviation
7.5, 42 to 77) were treated with OWHTO using a TomoFix plate. The
knees were divided into non-fracture (59 knees) and LHF (15 knees)
groups, and the LHF group was further divided into Takeuchi types
I, II, and III (seven, two, and six knees, respectively). The outcomes
were assessed pre-operatively and one year after OWHTO. Pre-operative
characteristics (age, gender and body mass index) showed no significant
difference between the two groups. The mean Japanese Orthopaedic
Association score was significantly improved one year after operation
regardless of the presence or absence of LHF (p = 0.0015, p <
0.001, respectively). However, six of seven type I cases had no
LHF-related complications; both type II cases had delayed union;
and of six type III cases, two had delayed union with correction
loss and one had overcorrection. These results suggest that Takeuchi
type II and III LHFs are structurally unstable compared with type
I. Cite this article:
We investigated the stability of seven Schatzker type II fractures of the lateral tibial plateau treated by subchondral screws and a buttress plate followed by immediate partial weight-bearing. In order to assess the stability of the fracture, weight-bearing inducible displacements of the fracture fragments and their migration over a one-year period were measured by differentially loaded radiostereometric analysis and standard radiostereometric analysis, respectively. The mean inducible craniocaudal fracture fragment displacements measured −0.30 mm (−0.73 to 0.02) at two weeks and 0.00 mm (−0.12 to 0.15) at 52 weeks. All inducible displacements were elastic in nature under all loads at each examination during follow-up. At one year, the mean craniocaudal migration of the fracture fragments was −0.34 mm (−1.64 to 1.51). Using radiostereometric methods, this case series has shown that in the Schatzker type II fractures investigated, internal fixation with subchondral screws and a buttress plate provided adequate stability to allow immediate post-operative partial weight-bearing, without harmful consequences.
We explored the outcome of staged bilateral total
knee replacement (TKR) for symmetrical degenerative joint disease
and deformity in terms of patient expectations, functional outcome
and satisfaction. From 2009 to 2011, 70 consecutive patients (41
female) with a mean age of 71.7 years (43 to 89) underwent 140 staged
bilateral TKRs at our institution, with a mean time between operations
of 7.8 months (2 to 25). Patients were assessed pre-operatively
and at six and 12 months post-operatively using the Short Form-12,
Oxford knee score (OKS), expectation questionnaire and satisfaction
score. The pre-operative OKS was significantly worse before the
first TKR (TKR1), but displayed significantly greater improvement
than that observed after the second TKR (TKR2). Expectation level
increased from TKR1 to TKR2 in 17% and decreased in 20%. Expectations
of pain relief and stair-climbing were less before TKR2; in contrast,
expectations of sporting and social activities were greater. Decreased expectations
of TKR2 were significantly associated with younger age and high
expectations before TKR1. Patient satisfaction was high for both
TKR1 (93%) and TKR2 (87%) but did not correlate significantly within
individuals. We concluded that satisfaction with one TKR does not
necessarily translate to satisfaction following the second. Cite this article:
In this retrospective study we evaluated the method of acute shortening and distraction osteogenesis for the treatment of tibial nonunion with bone loss in 17 patients with a mean age of 36 years (10 to 58). The mean bone loss was 5.6 cm (3 to 10). In infected cases, we performed the treatment in two stages. The mean follow-up time was 43.5 months (24 to 96). The mean time in external fixation was 8.0 months (4 to 13) and the mean external fixator index was 1.4 months/cm (1.1 to 1.8). There was no recurrence of infection. The bone evaluation results were excellent in 16 patients and good in one, while functional results were excellent in 15 and good in two. The complication rate was 1.2 per patient. We conclude that acute shortening and distraction osteogenesis is a safe, reliable and successful method for the treatment of tibial nonunion with bone loss, with a shorter period of treatment and lower rate of complication.
The lateral compartment is predominantly affected
in approximately 10% of patients with osteoarthritis of the knee. The
anatomy, kinematics and loading during movement differ considerably
between medial and lateral compartments of the knee. This in the
main explains the relative protection of the lateral compartment
compared with the medial compartment in the development of osteoarthritis.
The aetiology of lateral compartment osteoarthritis can be idiopathic,
usually affecting the femur, or secondary to trauma commonly affecting
the tibia. Surgical management of lateral compartment osteoarthritis
can include osteotomy, unicompartmental knee replacement and total
knee replacement. This review discusses the biomechanics, pathogenesis
and development of lateral compartment osteoarthritis and its management. Cite this article:
Medial open-wedge high tibial osteotomy has been gaining popularity in recent years, but adequate supporting material is required in the osteotomy gap for early weight-bearing and rapid union. The purpose of this study was to investigate whether the implantation of a polycaprolactone-tricalcium phosphate composite scaffold wedge would enhance healing of the osteotomy in a micro pig model. We carried out open-wedge high tibial osteotomies in 12 micro pigs aged from 12 to 16 months. A scaffold wedge was inserted into six of the osteotomies while the other six were left open. Bone healing was evaluated after three and six months using plain radiographs, CT scans, measurement of the bone mineral density and histological examination. Complete bone union was obtained at six months in both groups. There was no collapse at the osteotomy site, loss of correction or failure of fixation in either group. Staining with haematoxylin and eosin demonstrated that there was infiltration of new bone tissue into the macropores and along the periphery of the implanted scaffold in the scaffold group. The CT scans and measurement of the bone mineral density showed that at six months specimens in the scaffold group had a higher bone mineral density than in the control group, although the implantation of the polycaprolactone-tricalcium phosphate composite scaffold wedge did not enhance healing of the osteotomy.
A total of 25 children (37 legs and 51 segments) with coronal plane deformities around the knee were treated with the extraperiosteal application of a flexible two-hole plate and screws. The mean age was 11.6 years (5.5 to 14.9), the median angle of deformity treated was 8.3° and mean time for correction was 16.1 months (7 to 37.3). There was a mean rate of correction of 0.7° per month in the femur (0.3° to 1.5°), 0.5° per month in the tibia (0.1° to 0.9°) and 1.2° per month (0.1° to 2.2°) if femur and tibia were treated concurrently. Correction was faster if the child was under 10 years of age (p = 0.05). The patients were reviewed between six and 32 months after plate removal. One child had a rebound deformity but no permanent physeal tethers were encountered. The guided growth technique, as performed using a flexible titanium plate, is simple and safe for treating periarticular deformities of the leg.