Ligament Balancing Research Articles

Joint distraction force changes the three-dimensional articulation of the femur and tibia in total knee arthroplasty: a cadaveric study.

The purpose of this study was to test the hypotheses that the joint distraction force changes the three-dimensional articulation between the femur and the tibia and that the presence of posterior cruciate ligament (PCL) affects the three-dimensional articulation during joint gap evaluation in total knee arthroplasty (TKA). Cruciate-retaining TKA procedures were performed on 6 cadaveric knees using a navigation system. The joint center gap and varus ligament balance were measured using Offset Repo-Tensor® with the knee at 90° of flexion before and after PCL resection for joint distraction forces of 89, 178, and 266N. The three-dimensional location of the tibia relative to the femur and the axial rotational angle of the tibia were also assessed. Regardless of PCL resection, the joint center gap became larger (p = 0.002, p = 0.020) and varus ligament balance became more varus (p = 0.002, p = 0.002) with increasing joint distraction force, whereas the tibia was more internally rotated (p = 0.015, p = 0.009) and more anteriorly located (p = 0.004, p = 0.009). The tibia was more internally rotated (p = 0.015) and more posteriorly located (p = 0.026) after PCL resection than before resection. Joint distraction force changed three-dimensional articulation regardless of PCL preservation. PCL function was revealed as a factor restraining both tibial posterior translation and internal rotation. Surgeons should recognize that joint gap evaluation using a tensor device is subject to three-dimensional changes depending on the magnitude of the joint distraction force.

Medial knee stability at flexion increases tibial internal rotation and knee flexion angle after posterior-stabilized total knee arthroplasty

BackgroundSoft-tissue balance is an important element for the success of total knee arthroplasty; however, the influence of intraoperative soft-tissue balance on knee kinematics in posterior-stabilized-total knee arthroplasty remains unknown. We investigated whether intraoperative soft-tissue balance could influence knee kinematics and flexion angle after posterior-stabilized-total knee arthroplasty. MethodsThis study included 30 patients with knee osteoarthritis and varus alignment who underwent posterior-stabilized total knee arthroplasty; intraoperative soft-tissue balance parameters, such as varus ligament balance and joint component gap, were assessed by an offset-type tensor at knee flexion angles of 0°, 10°, 30°, 60°, 90°, 120°, and 135°. Medial and lateral compartment gaps were calculated. The amount of tibial internal rotation was determined between 60° and 135° flexion by the navigation system. Simple linear regression analysis was used to analyze the effects of intraoperative soft-tissue balance on tibial internal rotation. Linear regression analysis was used to assess correlation between tibial internal rotation and postoperative knee flexion angle. FindingsMedial compartment gaps at 60° (r = −0.57, P < 0.05) and 90° (r = −0.60, P < 0.05) of flexion were significantly negatively correlated with tibial internal rotation. Moreover, tibial internal rotation showed a significant correlation with the 2-year postoperative knee flexion angle (r = 0.50, P < 0.05) and improvement in knee flexion angle (r = 0.61, P < 0.05). InterpretationThus, smaller medial compartment gaps at 60° and 90° of flexion play an important role in achieving medial pivot motion with tibial internal rotation; moreover, tibial internal rotation provides a better flexion angle after posterior-stabilized total knee arthroplasty.

Arthroplasty of the proximal interphalangeal joint with the Tactys® modular prosthesis: Results in case of index finger and clinodactyly

There are various surgical solutions for arthrosis of the proximal interphalangeal (PIP) joint: arthrodesis or denervation. Clinodactyly that is major and the index fingers are traditional contraindications for PIP arthroplasty prostheses. The recurrence of clinodactyly with ligament imbalance and mechanical complications are known complications. The purpose of our study was to evaluate the objective and subjective clinical results and radiological complications of Tactys® prostheses on the PIP joint of the index fingers or with clinodactyly of more than 5° in the other fingers. Two surgeons have implanted 35 total gliding modular Tactys® prostheses in 29 women and 3 men since 2010. The indications for surgery were arthrotic and painful PIP joints. Average pre-op clinodactyly was 7.03° (5–30°) with ulnar deviation (29 cases). Eleven index fingers presented with average clinodactyly of 14.2° (10–20°). The digits operated on were as follows: 13 index fingers, 14 middle fingers, 5 ring fingers and 3 little fingers. Arthrosis was primitive in 23 cases, post-traumatic in 6 cases and rheumatoid in 6 cases. The average age of patients undergoing surgery was 63.7 years (40–85). Objective (mobility, strength, index finger exclusion, scores, clinodactyly) and subjective (patient satisfaction, pain) functional results were collected by a neutral and independent observer, as were radiological complications. With an average follow-up of 2.6 years (1–6.3), the range of motion in all digits improved by 5.4° on average (55.5–60.8). The improvement in range of motion in the index fingers was 4.5° (57–61.5). Clinodactyly in all fingers was corrected by 1.36° (0–20). In the index fingers, average clinodactyly was 1.3° (0–10). The pinch strength in all PIP joints improved significantly from 2.3 kg (0.5–5) to 3.7 kg (1–8). On the PIP of the index fingers, the pinch strength had increased significantly from 2.5 kg (1–4) before surgery to 3.8 kg (1–7.5) post-op. Functional scores improved: PRWE (from 55.36 to 26.7/100), Quick DASH (from 54.6 to 30.5/100). Patient satisfaction was excellent in 15 cases, good in 8 cases, average in 10 cases, poor in 2 cases. The average VAS Pain Score improved from 5.6 to 1.45. We found 3 major complications requiring surgery: 2 stiffening and 1 mechanical loosening with secondary arthrodesis. Five patients presented with non-troublesome, reducible swan neck deformity and one algodystrophy. A gliding, fixed Tactys® prosthesis allowed us to restore ligament balance and to optimally rebalance the periarticular structures. The improvement in range of motion and the correction of clinodactyly was maintained over time. Total arthroplasty of the PIP with a Tactys® is no longer a formal contraindication for the index fingers and in cases of clinodactyly of more than 5°.

Robotic-assisted Medial Unicompartmental Knee Arthroplasty: Options and Outcomes.

Medial unicompartmental knee arthroplasty (UKA) has several benefits over total knee arthroplasty for the surgical treatment of isolated medial compartmental arthritis in the knee, including reduced surgical risk and postoperative morbidity, rapid recovery, more normal kinematics, greater patient satisfaction, and shorter hospitalization. Nonetheless, there is substantial concern about the higher revision rates and lower survivorship in UKA compared to those in total knee arthroplasty. Robotic assistance has been advanced to improve the precision of bone preparation, component alignment, and quantified ligament balance in UKA, with the ultimate goal of improving kinematics and implant survivorship. Two currently available semiautonomous robotic platforms have demonstrated improved accuracy, and emerging short-term follow-up has demonstrated satisfactory functional outcomes. Further studies will be needed to determine if these technologies indeed have a meaningful impact on patient outcomes and survivorship in the mid- to long term.

Medial and lateral gap laxity differential in computer-assisted kinematic total knee arthroplasty.

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). Postoperative limb alignment did not affect outcomes. The standing hip-knee-ankle (HKA) angle was the sole positive predictor of the joint line convergence angle (JLCA) (p < 0.001). Increasing lateral flexion gap laxity was consistently associated with better outcomes. Lateral flexion gap laxity did not correlate with HKA angle, the JLCA, or lateral extension gap laxity. Minor releases were required in one third of cases. The standing HKA angle is the primary determinant of the JLCA in KTKA. A rectangular flexion gap is produced in only 11% of cases. Lateral flexion gap laxity is consistently associated with better outcomes and does not affect balance in extension. Minor releases are sometimes required as well, particularly in limbs with larger preoperative deformities. Cite this article: Bone Joint J 2019;101-B:331-339.

Computer-assisted surgery in total knee replacement: advantages, surgical procedure and review of the literature.

Introduction: Total knee replacement (TKR) is one of the most frequent orthopaedic procedures performed every year. At the same time 20% of patients who underwent TKR are not satisfied with the outcome. The reasons are unknown; we think that a mechanical alignment beyond 3° of varus-valgus can represent the most important cause of failure of TKR and consequently patient dissatisfaction. Materials and Methods: Neutral mechanical alignment is the main goal in every TKR: this can be achieved through different tools, such as extramedullary and intramedullary guides, patient-specific instrumentation (PSI) and computer-assisted surgery (CAS). The aim of this review is to compare the different alignment techniques in TKR, to describe CAS procedure and CAS results in recent literature. Results: Regarding the intramedullary guide, there is an increased risk of fatty embolism; there are great limitations on its use, or even impossibility, in cases of bone deformity and sequelae of trauma. Regarding the extramedullary guide, it becomes more difficult to use in cases of great obesity or increased soft-tissue volume around the tibia. PSI for TKR has been introduced to improve alignment, reduce outliers, operation time and the risk of fatty embolism by avoidance of intramedullary canal violation. Recent randomized controlled trials and meta-analysis proved no advantage of PSI in improving mechanical axis and implant survivorship. Discussion: CAS has provided to be a useful tool in assisting the surgeon to achieve more accurate post-operative mechanical axis through precise and reproducible bone cuts and ligament balancing. Two meta-analyses definitively proved that CAS technique improves mechanical axis and implant survivorship and one recent meta-analysis demonstrated that CAS provides better mechanical alignment and higher functional scores at short-term follow-up. (www.actabiomedica.it)

An intraoperative load sensor did not improve the early postoperative results of posterior-stabilized TKA for osteoarthritis with varus deformities.

In the present study, the early results of sensor-assisted versus manually balanced posterior-stabilized total knee arthroplasty (TKA) for osteoarthritis with varus deformities were prospectively compared. Fifty patients undergoing sensor-assisted TKA (group S) and 50 patients receiving manually balanced TKA (group M) were prospectively compared. The groups did not differ in terms of demographics, preoperative clinical status, or severity of deformity. The knee and function scores (KS and FS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and range of motion (ROM) were evaluated clinically. The mechanical axes and positions of components were assessed radiographically. In sensor-assisted TKA, the medial and lateral compartment loads were compared based on the patellar positions of inversion and eversion. There was no between-group difference in the postoperative KS or FS (n.s., respectively). The average postoperative WOMAC score was 17.0 in group S and 18.0 in group M (n.s.). The ROM was 131.2° in group S and 130.8° in group M (n.s.). Neither the postoperative alignment of the mechanical axis nor the component positioning differed between the groups (n.s.). In sensor-assisted TKA, the difference between the medial and lateral compartment loads was less than 15lbs (6.8kg) in each knee. The lateral compartment load increased after patellar eversion (p < 0.001). There are concerns about the cost-benefit ratio of the intraoperative load sensor, despite its advantage of more precisely assessing ligament balance without patellar eversion, which resulted in a smaller lateral gap. A long-term follow-up study with a large cohort is required. II.

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

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

Outcomes after knee arthroplasty in extra-articular deformity

To assess functional outcomes in patients undergoing total knee arthroplasty (TKA) without previous corrective osteotomy for treatment of knee osteoarthritis associated with extra-articular deformity. From January to December 2016, patients with knee osteoarthritis with extra-articular deformities who presented for preoperative assessment before TKA were evaluated prospectively. Physical and radiological characteristics were documented pre- and postoperatively. TKA was performed in 33 knees; 25 were considered for analysis. The mean age was 65.2years (range, 48-79years). Sixteen deformities were secondary to fractures and nine to failed osteotomies. The mean Knee Society Score (KSS) improved from 27.1 pre-operatively to 68.7 post-operatively (p = 0.000). Pre-operative mechanical axis ranged from 32° varus (negative) to 26° valgus. After correction, 20 knees were within 3° (varus or valgus) of mechanical alignment. In patients with extra-articular deformities, TKA with asymmetric intra-articular resection and ligament balancing can relieve pain and realign the mechanical axis of the lower limb.

Computed tomography confirmation of component rotation in nanosensor-balanced total knee arthroplasty.

Balanced gaps and proper rotation are felt to be essential for optimum range of motion, stability, and patellar tracking in total knee arthroplasty. The purpose of this study is to assess, using computed tomography, the rotation of femoral and tibial components in fresh-frozen human cadaver knees that have been balanced using nanosensor trials while also observing how this rotation affects measured compartment loads and requirement for ligament balancing adjustment. We found that minor degrees of rotational malalignment of the femur and tibia were common using standard instrumentation and measured resection technique. Quantitative balance and rotational congruence are aided by nanosensor guidance, and femoral malrotation of up to 8° does not appear to affect compartment loads significantly as long as rotational congruity is present.

Objective quantification of ligament balancing using VERASENSE in measured resection and modified gap balance total knee arthroplasty

BackgroundSoft tissue balancing which is above all most important factor of total knee arthroplasty, has been performed by subjective methods. Recently objective orthosensor has been developed for compartment pressure measurement. The purpose of this study was: (1) to quantify the compartment pressure of the joint throughout the range of motion during TKA using orthosensor, (2) to determine the usefulness of orthosensor by analyzing correlation between the pressure in both compartment with initial trial and after final implantation, and (3) to evaluate the types and effectiveness of additional ligament balancing procedures to compartment pressure.MethodsEighty-four patients underwent total knee arthroplasty (TKA) using VERASENSE Knee System. TKA was performed by measured resection and modified gap balance technique. Compartment pressure was recorded on full extension, 30°, 60°, 90° and full flexion at initial (INI), after each additional procedure, and after final (FIN) implantation. “Balanced” knees were defined as when the compartment pressure difference was less than 15 pounds.ResultsThirty patients (35.7%) showed balanced knee initially and 79 patients (94.0%) showed balance after final implantation. The proportion of balanced knee after initial bony resection, modified gap balancing TKAs showed significantly higher proportion than measured resection TKAs (P = 0.004) On both compartment, the pressure was generally decreased throughout the range of motion. Linear correlation on both compartment showed statistically significant throughout the range on motion, with higher correlation value on the lateral compartment. Total 66 additional ligament balancing procedures were performed.ConclusionUsing orthosensor, we could obtain 94% quantified balance knee, consequently. And between the techniques, measured resection TKA showed less balanced knee and also required more additional procedures compared to modified gap balancing TKA. Furthermore, with the acquired quantified data during appropriate ligament balancing, the surgeon could eventually reduce the complications associated with soft tissue imbalance in the future.

Outcomes of Total Ankle Arthroplasty in Moderate and Severe Valgus Deformity

Category: Ankle Arthritis Introduction/Purpose: Among patients with end-stage ankle arthritis, total ankle arthroplasty (TAA) utilization has significantly increased in recent years, while ankle arthrodesis utilization has declined. Significant coronal plane deformity is frequently encountered in this patient population, and was previously considered a contraindication to TAA. However, the advent of newer fixed-bearing prostheses, coupled with improved surgical techniques and a better understanding of ligamentous balancing, have allowed surgeons to extend their indications for TAA with respect to deformity correction. Several authors have demonstrated good outcomes from TAA in patients with significant varus deformities, but not specifically in patients with valgus deformities. We aimed to determine the clinical, radiographic, and patient-reported outcomes of patients with moderate to severe valgus deformity who underwent TAA for end-stage ankle arthritis. Methods: Eighty patients with valgus deformities =10 degrees who underwent TAA were retrospectively reviewed. All surgeries were performed by one of three fellowship-trained orthopaedic foot and ankle surgeons with extensive experience in TAA. One of three prostheses were used: INBONE (Wright Medical Technology, Arlington, TN), Salto-Talaris (Integra, Plainsboro, NJ), or the Scandinavian Total Ankle Replacement (STAR; Stryker, Kalamazoo, MI). We assessed the coronal tibiotalar angle on standardized weightbearing radiographs preoperatively, at one year, and at final follow-up. The visual analog scale (VAS) for pain, Short Form (SF)-36 scale, American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot-ankle scale, and Short Musculoskeletal Function Assessment (SMFA) scores were assessed preoperatively and at final follow-up. Subgroup analyses were performed to determine differences in outcome scores, deformity correction, and maintenance of alignment between patients with moderate (=10 degrees, &lt;20 degrees) and severe (&gt;20 degrees) preoperative deformity. Complication, reoperation, and revision rates were collected from chart review. Results: Mean preoperative valgus deformity was 15.5 ± 5.0 degrees, and was corrected to a mean 1.2 ± 2.6 degrees of valgus postoperatively (Figure; P&lt;.001). An associated flatfoot deformity was present in 33% of patients, 65% of whom required concomitant procedures to address associated deformity. The VAS, SF-36, AOFAS, and SMFA scores improved significantly postoperatively (P&lt;.001 for all), with no difference in amount of improvement between the moderate and severe deformity groups. Deformity correction was maintained at a mean 3.5 (range 2.0-5.9) years of follow-up, with no significant change in the mean tibiotalar angle between one year and final follow-up in either the moderate or severe deformity groups (P=.134 and P=.155, respectively). Reoperation and revision rates did not differ between the moderate and severe deformity groups. Conclusion: Correction of coronal alignment was achieved and maintained following TAA in patients with both moderate and severe preoperative valgus malalignment. Patients demonstrated significant improvement in patient-reported outcome scores regardless of amount of preoperative deformity. Additional procedures may be necessary at the time of TAA to balance the ankle and correct associated deformity in the foot.

Measuring the sensitivity of total knee replacement kinematics and laxity to soft tissue imbalances

Ligament balancing during total knee replacement (TKR) is receiving increased attention due to its influence on resulting joint kinematics and laxity. We employed a novel in vitro technique to measure the kinematics and laxity of TKR implants during gait, and measured how these characteristics are influenced by implant shape and soft tissue balancing, simulated using virtual ligaments. Compared with virtual ligaments that were equally balanced in flexion and extension, the largest changes in stance-phase tibiofemoral AP and IE kinematics occurred when the virtual ligaments were simulated to be tighter in extension (tibia offset 1.0 ± 0.1 mm posterior and 3.6 ± 0.1° externally rotated). Virtual ligaments which were tight in flexion caused the largest swing-phase changes in AP kinematics (tibia offset 2.3 ± 0.2 mm), whereas ligaments which were tight in extension caused the largest swing-phase changes in IE kinematics (4.2 ± 0.1° externally rotated). When AP and IE loads were superimposed upon normal gait loads, incremental changes in AP and IE kinematics occurred (similar to laxity testing); and these incremental changes were smallest for joints with virtual ligaments that were tight in extension (in both the stance and swing phases). Two different implant designs (symmetric versus medially congruent) exhibited different kinematics and sensitivities to superimposed loads, but demonstrated similar responses to changes in ligament balancing. Our results demonstrate the potential for pre-clinical testing of implants using joint motion simulators with virtual soft tissues to better understand how ligament balancing affects implant motion.

No detrimental effect of ligament balancing on functional outcome after total knee arthroplasty: a prospective cohort study on 129 mechanically aligned knees with 3 years’ follow-up

Background and purpose — In the classical mechanical alignment technique, ligament balancing is considered a prerequisite for good function and endurance in total knee arthroplasty (TKA). However, it has been argued that ligament balancing may have a negative effect on knee function, and some authors advocate anatomic or kinematic alignment in order to reduce the extent of ligament releases. The effect of the trauma induced by ligament balancing on functional outcome is unknown; therefore, the aim of this study was to investigate this effect.Patients and methods — 129 knees (73 women) were investigated. Mean age was 69 years (42–82), and mean BMI was 29 (20–43). Preoperatively 103 knees had a varus deformity, 21 knees had valgus deformity, and 5 knees were neutral. The primary outcome measure was the Knee injury and Osteoarthritis Outcome Score (KOOS). Secondary outcome measures were the Oxford Knee Score (OKS) and patient satisfaction (VAS). All ligament releases were registered intraoperatively and outcome at 3 years’ follow-up in knees with and without ligament balancing was comparedResults — 86 knees were ligament balanced and 43 knees were not. Ligament-balanced varus knees had more preoperative deformity than varus knees without ligament balancing (p = 0.01). There were no statistically significant differences in outcomes between ligament-balanced and non-ligament-balanced knees at 3 years’ follow-up. No correlation was found between increasing numbers of soft tissue structures released and outcome.Interpretation — We did not find any negative effect of the trauma induced by ligament balancing on knee function after 3 years.

Total Ankle Replacement in Obese and Young Patients

End-stage ankle arthritis is an increasingly common pathology that results in significant physical and mental disability. Historically, treating the young and obese patient with a total ankle replacement (TAR) resulted in high failure rates. However, with modern advances in prosthesis design and understanding of ligamentous balancing, the use of TAR for ankle arthritis has been increasing in popularity. This article discusses the considerations, techniques used, and the current literature regarding the use of TAR in the young and obese patient. Level of Evidence: Diagnostic Level V. See Instructions for Authors for a complete description of levels of evidence.

Increased valgus laxity in flexion with greater tibial resection depth following total knee arthroplasty.

Soft tissue balancing is of central importance to outcome following total knee arthroplasty (TKA). However, there are lack of data analysing the effect of tibial bone cut thickness on valgus laxity. A cadaveric study was undertaken to assess the biomechanical consequences of tibial resection depth on through range knee joint valgus stability. We aimed to establish a maximum tibial resection depth, beyond which medial collateral ligament balancing becomes challenging, and a constrained implant should be considered. Eleven cadaveric specimens were included for analysis. The biomechanical effects of increasing tibial resection were studied, with bone cuts made at 6, 10, 14, 18 and 24mm from the lateral tibial articular surface. A computer navigation system was used to perform the tibial resection and to measure the valgus laxity resulting from a torque of 10Nm. Measurements were taken in four knee positions: 0° or extension, 30°, 60° and 90° of flexion. Intra-observer reliability was assessed. A minimum sample size of eight cadavers was necessary. Statistical analysis was performed using a nonparametric Spearman's ranking correlation matrix at the different stages: in extension, at 30°, 60° and 90° of knee flexion. Significance was set at p < 0.05. There was no macroscopic injury to the dMCL or sMCL in any of the specimens during tibial resection. There was no significant correlation found between the degree of valgus laxity and the thickness of the tibial cut with the knee in extension. There was a statistically significant correlation between valgus laxity and the thickness of the tibial cut in all other knee flexion positions: 30° (p < 0.0001), 60° (p < 0.001) and 90° (p < 0.0001). We identified greater than 5° of valgus laxity, at 90° of knee flexion, after a tibial resection of 14mm. Increased tibial resection depth is associated with significantly greater valgus laxity when tested in positions from 30° to 90° of flexion, despite stability in extension. Greater than 5° of laxity was identified with a tibial resection of 14mm. When a tibial bone cut of 14mm or greater is necessary, as may occur with severe preoperative coronal plane deformity, it is recommended to consider the use of a constrained knee prosthesis.

Short-term and mid-term results of lateral condyle sliding osteotomy in the treatment of valgus total knee arthroplasty: A successful therapy option in Grade 2 valgus total knee arthroplasty

BackgroundDifferent methods exist for deformity correction and ligament balancing in total knee arthroplasty (TKA) of valgus knees, the sliding osteotomy being one of them. The objective of the current study was to analyze the clinical and radiological short-term and mid-term results of this technique in a larger series. MethodsBetween June 2007 and May 2014, 98 patients were treated with 98 TKAs and a simultaneous sliding osteotomy. All of them had a Grade 2 fixed valgus deformity (between 10° and 20°). All patients received a mobile-bearing, non-constrained (CR) implant. After prospective inclusion (T1), patients were clinically assessed after one (T2) and 4.5years (±2.1years) (T3), and radiological and Oxford Knee Score (OKS), Knee Society Knee Score (KSS) and the Knee Society Function Score (KSF) were obtained. ResultsAll knees were corrected to a mechanical leg alignment within three degrees. Significant improvement of all scores could be measured at T2 and T3. Seven revisions needed to be performed; three of them were procedure-related. In two of them, a problem of capsular closure occurred, while in one the slided epicondyle dislocated after three months. All other revisions were performed because of non-procedure-related problems (e.g. infection). ConclusionsSliding osteotomy of the lateral condyle is a successful option for the treatment of Grade 2 fixed valgus deformity. Due to this technique, higher constraint could be avoided. The results stayed constant over time. The procedure-related complications need to be kept in mind. Long-term results still need to be awaited.

The Role of the Tourniquet and Patella Position on the Compartmental Loads During Sensor-Assisted Total Knee Arthroplasty

BackgroundAn inflated tourniquet may diminish the natural excursion of the extensor mechanism and alter compartmental loads, affecting the surgeon's ability to accurately assess ligament balance during total knee arthroplasty (TKA). In addition, patella position (reduced, lateralized, or everted) has also been known to affect compartmental loads. This study used intraoperative sensing to assess how a combination of tourniquet inflation and patella position may affect medial and lateral compartmental loads during sensor-assisted TKA. MethodsFifty-six patients (13 men) with a mean age of 66 years (standard deviation, 8.66) and mean BMI of 31 kg/m2 (standard deviation, 6.66) undergoing primary cemented TKA for primary osteoarthritis were enrolled. After final prosthetic implantation, with the tourniquet inflated, medial and lateral compartment loads were obtained in the 10°, 45°, and 90° of flexion with the patella in reduced, lateralized, or everted positions. The tourniquet was deflated and this process repeated. Surgeons were blinded to the values as to not influence medial and lateral stressing of the knee. Linear regression was used to evaluate absolute loads. ResultsTourniquet inflation did not significantly alter compartmental loads regardless of knee flexion or patella position. Lateral compartment loads significantly increased as the patella moved from the reduced, to the lateralized, to the everted position with the tourniquet inflated or deflated. ConclusionTourniquet inflation did not significantly alter compartmental loads during sensor-assisted TKA. However, irrespective of tourniquet use, a lateralized or everted patellar position significantly increased lateral compartment loads.

Editorial on: is the use of spreaders an accurate method for ligament balancing?

Total knee arthroplasty (TKA) has become successfully performed procedure for knee osteoarthritis. Accurate alignment of knee implants and soft tissue balance during TKA may induce reproduction of stable tibiofemoral and patellofemoral (PF) joints (1,2). Therefore, appropriate methods are necessary for assessment of soft tissue balance. Spreader and Spacer blocks are commonly used.

Total Knee Arthroplasty in Patients With Prior Anterior Cruciate Ligament Reconstruction

BackgroundFew studies have analyzed the outcomes of total knee arthroplasty (TKA) in patients with prior anterior cruciate ligament (ACL) reconstruction, and the reported outcomes are controversial. The purpose of this study is to assess if prior ACL reconstruction had any impact on the outcome of subsequent TKA. MethodsA matched case-control study was conducted in patients who underwent TKA, including 37 with prior ACL reconstruction and 37 patients without ACL reconstruction. Preoperative and postoperative clinical and radiological data were collected from a prospective arthroplasty database with a minimum follow-up of 5 years. The mean age was 69.6 years, and 59.4% were men. The Knee Society scores, Short Form-12, and Western Ontario and McMaster Universities questionnaires were used for functional evaluations. Visual analogue scale 0-10 was used for patient satisfaction. ResultsThe mean follow-up after TKA was 6.1 (range 5-7.3) years. Two patients in the ACL group developed knee stiffness requiring manipulation under anesthesia, while 1 patient in the control group suffered superficial wound infection. At last follow-up, no significant differences in functional or radiologic outcomes were found between both groups. The performance of TKA in ACL patients had increased technical difficulty and significantly longer time of surgery, but this had no influence on the outcomes. In the ACL group, 24 knees had technical difficulty in surgery. The main difficulty in most ACL patients was due to varus deformity and increased retraction of the medial soft structures which required progressive medial release. Other 2 knees had difficult knee exposure. One was an unexpected partial patellar tendon avulsion and the other required planned quadriceps snip. ConclusionTKA was an effective procedure for patients with prior ACL reconstruction. The surgeon should be warned of the possible difficulties in the knee exposure and possible need of medial release to obtain an appropriate ligament balance. However, these additional procedures had no negative effect on the outcomes of TKA.