INTRODUCTION. Achieving balance in TKA is critical in assuring favorable outcomes. But, in order to achieve quantifiably balanced loading values, is it more advantageous to make bony corrections or release soft-tissue? The answer to this question will be paramount in evaluating the most appropriate surgical techniques for use with new dynamic technology, thereby maximizing favorable clinical outcomes. Therefore, the purpose of this investigation was to evaluate a possible quantitative loading threshold, using intraoperative sensors, which may dictate surgical correction of bone versus soft-tissue release. METHODS. A retrospective analysis of 122 multicenter patients, in receipt of sensor-assisted primary TKA, was conducted. 40 lbs. was used as a threshold, above which bone was corrected; below which soft-tissue was corrected. All patients were categorized in to the following groups: Group A – candidates for bony correction, but received soft-tissue correction; Group B – candidates for soft-tissue/receiving soft-tissue; Group C – candidates for bony correction/receiving bony correction. RESULTS. The patient groups that followed the surgical algorithm appropriately (loading ≥ 40 lbs. dictates bony correction; loading < 40 lbs. dictates soft-tissue correction) reported significantly higher clinical outcomes scores (KSS and WOMAC) and satisfaction, 1-year following primary TKA. DISCUSSION AND CONCLUSIONS. Novel technology, such as intraoperative sensing, has provided surgeons with unprecedented access to information regarding the kinetic/kinematic nature of knee joints. In order to mitigate recurring complications after primary TKA, it is imperative that sensing output and clinical outcomes are correlated and studied in order to maximize patient benefits. In this investigation, it was observed that a 40 lb. threshold provided a clinically relevant delineation between when to correct bone, and when to adjust soft-tissue. When that algorithm was applied, patients reported significantly better clinical outcomes than when the algorithm was not applied

Introduction. Instability after total knee arthroplasty (TKA) represents, in excess of, 7% of reasons for implant failure. This mode of failure is correlated with soft-tissue imbalance, and has continued to be problematic despite advances in implant technology. Thus, understanding the options available to execute safe and effective soft-tissue release is critical to mitigating future complications due to instability. This study aimed to use intraoperative sensors to evaluate a multiple needle puncturing technique (MNPT), in comparison with traditional transection-based release, to determine its biomechanical and clinical efficacy. Methods. Seventy-five consecutive, cruciate-retaining TKAs were performed, as part of an 8-site multicenter study. All procedures were performed with the use of an intraoperative sensor to ensure quantitative balance, as per previously reported literature. Of the 75-patient cohort, 50 patients were balanced with the MNPT; 20 patients were balanced with traditional transection. All patients were followed out to 1-year, and administered KSS, WOMAC, and satisfaction. Alignment and ROM was captured for all patients, pre-operatively and at the 1-year follow-up interval. Results. All patient joints could be released to a balanced joint state, regardless of technique used. There was no significant difference between the two groups (MNPT vs. transection), pre-operatively, with respect to range of motion or alignment (114° MNPT; 114° transection). At 1-year, post-operatively, there was no significant difference in WOMAC score, KSS scores, satisfaction, or ROM (Respectively: 13.1 MNPT vs. 14.6 transection; 174.9 MNPT vs.176.5 transection; 31.7 “Very Satisfied” MNPT vs. 32.2 “Very Satisfied” transection; 124° MNPT vs. 125° transection). No adverse outcomes related to balancing technique have been reported. Discussion. Instability contributes to the current 2.7 billion dollar TKA revision burden in the United States. Understanding the efficacy of different techniques in soft-tissue balancing may help to mitigate unfavorable complications. In this study, it was found that the MNPT is just as safe and effective at achieving soft-tissue balance as transectional release techniques, and showed no deviation from the achievement of optimal post-operative outcomes at 1-year. This technique, when used with intraoperative sensors to quantify joint balance, may thereby offer a more controlled way to release soft-tissue, incrementally, to achieve precise balance

Introduction

Soft tissue releases are often required to correct deformity and achieve gap balance in total knee arthroplasty (TKA). However, the process of releasing soft tissues can be subjective and highly variable and is often perceived as an ‘art’ in TKA surgery. Releasing soft tissues also increases the risk of iatrogenic injury and may be detrimental to the mechanically sensitive afferent nerve fibers which participate in the regulation of knee joint stability.

Measured resection TKA approaches typically rely on making bone cuts based off of generic alignment strategies and then releasing soft tissue afterwards to balance gaps. Conversely, gap-balancing techniques allow for pre-emptive adjustment of bone resections to achieve knee balance thereby potentially reducing the amount of ligament releases required. No study to our knowledge has compared the rates of soft tissue release in these two techniques, however. The objective of this study was, therefore, to compare the rates of soft tissue releases required to achieve a balanced knee in tibial-first gap-balancing versus femur-first measured-resection techniques in robotic assisted TKA, and to compare with release rates reported in the literature for conventional, measured resection TKA [1].

Introduction

In total knee arthroplasty (TKA), component realignment with bone-based surgical correction (BBSC) can provide soft tissue balance and avoid the unpredictability of soft tissue releases (STR) and potential for more post-operative pain. Robotic-assisted TKA enhances the ability to accurately control bone resection and implant position. The purpose of this study was to identify preoperative and intraoperative predictors for soft tissue release where maximum use of component realignment was desired.

Introduction

The effect of each step of medial soft tissue release was assessed taking the expansion strength and patellar condition into account in five fresh frozen normal cadaver specimens.

Introduction. Accurate alignment of components in total knee arthroplasty (TKA) is a known factor that contributes to improvement of post-operative kinematics and survivorship of the prosthetic joint. Recently, CAOS has been introduced into TKA in effort to reduce positioning variability that may deviate from the mechanical axis. However, literature suggests that clinical outcomes following TKA with CAOS may not present a significant improvement from traditional methods of implantation. This would infer that achieving correct alignment, alone, might be insufficient for ensuring an optimal reconstruction of the joint. Therefore, this study seeks to evaluate the importance of soft-tissue balancing, through the quantification of joint kinetics collected with intraoperative sensors, with or without the combined use of CAOS. Methods. Seven centers have contributed 215 patients who have undergone primary TKA with the use of intraoperative sensors. Of the 7 surgeons contributing patients to this study, 3 utilize CAOS; 4 utilize manual techniques. Along with standard demographic and surgical data being collected as per the multicenter study protocol, soft-tissue release techniques and medial-lateral intercompartmental loads—as indicated by the intraoperative sensors—were also captured pre- and post-release. “Optimal” balance was defined as a medial-lateral load difference of ≤ 15 lbs. A chi-squared analysis was performed to determine if the percentage of soft-tissue release was significantly different between the two groups: patients with CAOS, and patients without CAOS. Results. Of the 215 patients (35% with CAOS, 65% without CAOS) who have received TKA, using intraoperative sensors to assess mediolateral balance, 92.6% underwent soft-tissue release. Stratifying this data by surgical technique: 89% of the patients with CAOS, and 94% of patients without CAOS, were released. A chi-squared analysis—with 3 degrees of freedom; and 99% confidence—was executed to determine if the 5% difference between the two groups was significant. The analysis showed that there was no significant difference between the two groups, thus we can conclude that soft-tissue release is as equally necessary in the CAOS TKA group, as it is in the traditional TKA group. Discussion. It is widely accepted that correct alignment of TKA components contributes to improved kinematic function of the affected joint. Recently, technology has been developed to digitally guide surgeons through bony cuts, thereby decreasing the incidence of deviation from the mechanical axis. However, alignment may not be the foremost contributing factor in ensuring an optimal joint state. In this evaluation, 92.6% of the cohort required some degree of releasing of ligamentous structures surrounding the knee joint, regardless of intraoperative technique used. A chi-squared analysis of the data supports the claim that soft-tissue release is used in nearly all cases, irrespective of the use of CAOS (p < 0.001). This suggests that soft-tissue release is necessary in nearly all cases, even after appropriate alignment has been digitally verified. The data strongly supports the idea that obtaining an optimally functioning joint is multifactorial, and that alignment may play a more minor role in achieving ideal joint reconstruction than previously assumed, being superseded by the necessity to achieve soft-tissue balance

Introduction. Improper soft-tissue balancing can result in postoperative complications after total knee arthroplasty (TKA) and may lead to early revision. A single-use tibial insert trial with embedded sensor technology (VERASENSE from OrthoSensor Inc., Dania Beach, FL) was designed to provide feedback to the surgeon intraoperatively, with the goal to achieve a “well-balanced” knee throughout the range of motion (Roche et al. 2014). The purpose of this study was to quantify the effects of common soft-tissue releases as they related to sensor measured joint reactions and kinematics. Methods. Robotic testing was performed using four fresh-frozen cadaveric knee specimens implanted with appropriately sized instrumented trial implants (geometry based on a currently available TKA system). Sensor outputs included the locations and magnitudes of medial and lateral reaction forces. As a measure of tibiofemoral joint kinematics, medial and lateral reaction locations were resolved to femoral anterior-posterior displacement and internal-external tibial rotation (Fig 1.). Laxity style joint loading included discrete applications of ± 100 N A-P, ± 3 N/m I-E and ± 5 N/m varus-valgus (V-V) loads, each applied at 10, 45, and 90° of flexion. All tests included 20 N of compressive force. Laxity tests were performed before and after a specified series of soft-tissue releases, which included complete transection of the posterior cruciate ligament (PCL), superficial medial collateral ligament (sMCL), and the popliteus ligament (Table 1). Sensor outputs were recorded for each quasi-static test. Statistical results were quantified using regression formulas that related sensor outputs (reaction loads and kinematics) as a function of tissue release across all loading conditions. Significance was set for p-values ≤ 0.05. Results. Tissue releases, and in particular the sMCL and PCL, led to multiple findings, many of which were dependent on flexion (Table 2). For PCL resection, at 10° of flexion lateral and total joint loads decreased, whereas at 45 and 90° lateral load increased. In addition, there was a significant anterior shift of the femur that increased with flexion angle, while tibial rotation was only affected at 90°. sMCL release decreased the total load across all flexion angles, and impacted the medial load at 10° only. The only structure for which no significant relationship was discovered was the deep medial collateral ligament, as this variable was confounded on others. Discussion. One critical aspect of TKA is achieving appropriate soft-tissue balance to maximize postoperative performance. In this study, the sensor provided a direct measurement of joint loading and kinematics, which were related to surgically relevant soft-tissue releases. Results showed the sMCL to decrease joint loads and flexion dependent changes after PCL release, likely an indication of bundle specific response. Future work should be performed to examine the roles of individual ligament bundles, as well as graded effects of tissue releases. Overall, the results corroborate previous findings and provide a new and direct look at the role of ligaments in TKA. Significance. This study quantified relationships between surgically relevant tissue states and joint response in TKA. The data has the potential to be applied intraoperatively to guide soft-tissue releases. To view tables/figures, please contact authors directly

Background. Despite the success of total knee arthroplasty (TKA) restoration of normal function is often not achieved. Soft-tissue balance is a major factor leading to poor outcomes including malalignment, instability, excessive wear, and subluxation. Mechanical ligament balancers only measure the joint space in full extension and at 90° flexion. This study uses a novel electronic ligament balancer to measure the ligament balance in normal knees and in knees after TKA to determine the impact on passive and active kinematics. Methods. Fresh-frozen cadaver legs (N = 6) were obtained. A standard cruciate-retaining TKA was performed using measured resection approach and computer navigation (Stryker Navigation, Kalamazoo, MI). Ligament balance was measured using a novel electronic balancer (Fig 1, XO1, XpandOrtho, Inc, La Jolla, CA, USA). The XO1 balancer generates controlled femorotibial distraction of up to 120N. The balancer only requires a tibial cut and can be used before or after femoral cuts, or after trial implants have been mounted. The balancer monitors the distraction gap and the medial and lateral gaps in real time, and graphically displays gap measurements over the entire range of knee flexion. Gap measurements can be monitored during soft-tissue releases without removing the balancer. Knee kinematics were measured during active knee extension (Oxford knee rig) and during passive knee extension under varus and valgus external moment of 10Nm in a passive test rig. Sequence of testing and measurement:. Ligament balance was recorded with the XO1 balancer after the tibial cut, after measured resection of the femur, and after soft-tissue release and/or bone resection to balance flexion-extension and mediolateral gaps. Passive and active kinematics were measured in the normal knee before TKA, after measured resection TKA, and after soft-tissue release and/or bone resection to balance flexion-extension and mediolateral gaps. Results & Discussion. Overall the changes in knee balance affected passive kinematics more than active kinematics. Correcting a tight extension gap by resecting 4 mm from the distal femur had a significant effect on femoral rollback and tibial rotation and increased the varus-valgus laxity of the knee (Fig 2). Sequential release of the MCL increased active femoral rollback and tibial internal rotation primarily in flexion (Fig 3). Combinations of bone resections with ligament release had an additive effect. For example, MCL release combined with 2 mm resection of bone at the distal femoral cut increased total valgus laxity by 8° during passive testing. However, even after balancing the flexion-extension gap and the mediolateral gap knee kinematics were significantly different from the normal knee before TKA. Conclusions. The XO1 electronic balancer was very sensitive to changes in bone resection and sequential soft-tissue releases. Intraoperative ligament balance had a significant effect on active and passive kinematics. However, balancing the flexion-extension gap and the mediolateral gap did not restore kinematics to that of the normal knee. Ligament balance can have a profound impact on postoperative function, and that current recommendations for balancing the knee likely have to be reconsidered

Soft-tissue release plays an integral part in primary total knee arthroplasty by ‘balancing’ the knee. Asian patients often present late and consequently may have large deformities due to significant bone loss and contractures medially, and stretching of the lateral collateral ligament. Extra-articular deformities may aggravate the situation further and make correction of these deformities more arduous. Several techniques have been described for correction of deformity by soft-tissue releases. However, releasing the collateral ligament during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus deformity without performing a superficial medial collateral ligament release. The steps are: Determining pre-operatively whether deformity is predominantly intra-articular or extra-articular; Individualizing the valgus resection angle and bony resection depth; Reduction osteotomy, posteromedial capsule resection, sliding medial condylar osteotomy, extra-articular corrective osteotomy; Compensating for bone loss; Only rarely deploying a more constrained device. Case examples will be presented to illustrate the entire spectrum of varus deformities

Soft-tissue release plays an integral part in primary total knee arthroplasty by ‘balancing’ the knee. Asian patients often present late and consequently may have large deformities due to significant bone loss and contractures medially, and stretching of the lateral collateral ligament. Extra-articular deformities may aggravate the situation further and make correction of these deformities more arduous. Several techniques have been described for correction of deformity by soft-tissue releases. However, releasing the collateral ligament during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus deformity without performing a superficial medial collateral ligament release. The steps are: 1. Determining preoperatively whether deformity is predominantly intra-articular or extra-articular; 2. Individualizing the valgus resection angle and bony resection depth; 3. Reduction osteotomy, posteromedial capsule resection, sliding medial condylar osteotomy, extra-articular corrective osteotomy; 4. Compensating for bone loss; 5. Only rarely deploying a more constrained device. Case examples will be presented to illustrate the entire spectrum of varus deformities

Treatment for hip displacement in children and youth with cerebral palsy (CP) is dependent upon when the problem is detected. Hip surveillance aims to identify hip displacement early through systematic screening and, together with timely orthopaedic intervention, can eliminate the need for salvage hip procedures. Here we report the impact on surgical practice of 1) hip surveillance program advocacy and knowledge translation efforts and 2) initial population-based program implementation. A retrospective review was completed of all children with CP undergoing surgery for hip displacement at a provincial tertiary pediatric hospital in the years 2004 to 2018. Date and type of surgery, age at surgery, Gross Motor Function Classification System (GMFCS) level, and pre-operative migration percentages (MP) were collected. Surgeries were categorized as soft-tissue release, reconstructive, and salvage procedures. Results were collected for three time periods: historical (September 2004- June 2010), hip surveillance advocacy and knowledge translation (July 2010- August 2015), and post provincial hip surveillance program implementation (September 2015 – December 2018). A total of 261 surgeries on 321 hips were reviewed. The rate of salvage procedures dropped from 29% (24) of surgeries performed in the historical period to 12% (14) during the period that included targeted hip surveillance knowledge translation and development of provincial guidelines. Since implementation of the surveillance program, salvage procedures have accounted for 7% (4) of interventions performed; all of these were in patients new to the province or existing patients. During the three study periods, reconstructive surgeries accounted for 64%, 81%, and 80% of the interventions performed. The mean initial MP at time of reconstructive surgery has decreased from 66% (SD 20%) in the historical time period to 57% (SD 25%) and 57% (SD 22%) in the subsequent time periods. There were a greater number of children at GMFCS levels III and IV in the two more recent time periods suggesting surveillance may assist in identifying children at these levels of impairment. The rate of soft-tissue surgeries was low during all time periods with the number trending higher since program implementation (7%, 7%, 10%). Knowledge translation and use of standardized surveillance guidelines can have a significant impact on the prevalence of salvage hip surgeries. Centers should utilize existing surveillance guidelines and educate key stakeholders about the importance of hip surveillance in the absence of a formal hip surveillance program

Introduction. Achieving a balanced joint with neutral alignment is not always possible in total knee arthroplasty (TKA). Intra-operative compromises such as accepting some joint imbalance, non-neutral alignment or soft-tissue release may result in worse patient outcomes, however, it is unclear which compromise will most impact outcome. In this study we investigate the impact of post-operative soft tissue balance and component alignment on postoperative pain. Methods. 135 patients were prospectively enrolled in robot assisted TKA with a digital joint tensioning tool (OMNIBotics with BalanceBot, Corin USA) (57% female; 67.0 ± 8.1 y/o; BMI: 31.9 ± 4.8 kg/m. 2. ). All surgeries were performed with a PCL sacrificing tibia or femur first techniques technique, using CR femoral components and a deep dish tibial insert (APEX, Corin USA). Gap measurements were acquired under load (average 80 N) throughout the range of motion during trialing with the tensioning tool inserted in place of the tibial trial. Component alignment parameters and post-operative joint gaps throughout flexion were recorded. Patients completed 1-year KOOS pain questionnaires. Spearman correlations and Mann-Whitney-U tests were used to investigate continuous and categorical data respectively. All analysis performed in R 3.5.3. Results. Significant correlations were found between KOOS Pain and joint balance (p < 0.05). Joint gap thresholds of an equally balanced or tighter medial compartment in extension, ±1 mm medial laxity compared to the final insert thickness in midflexion, and medio-lateral imbalance < 1.5 mm in flexion generated subgroups with significantly improved pain outcomes (median Δ = 8.3, 5.6 and 2.8 points, respectively). When all joint balance thresholds were satisfied, further improved outcomes resulted (median Δ = 11.2, p = 0.0018) (Figure 1 Left). No significant correlations were identified between femoral coronal (0.8 ± 2.1° valgus) and axial (2.1 ± 2.7° external) or tibiofemoral extension (1.1 ± 2.4° varus) and flexion (2.4 ± 2.8° varus) coronal alignments and KOOS Pain. Neutral and non-neutral femoral (±3° coronal and 0° – 5° external) and tibiofemoral (±3° coronal and −2° − 5° external) subgroups also reported no difference in KOOS pain outcome (Figure 1 Right). Discussion and Conclusion. The gap profiles identified here help build the understanding of joint balance and its relationship with outcome when using a PCL sacrificing deep dish tibial insert. Using a digitally-controlled distraction device, joint gap windows of clinical relevance were identified with statistically improved patient outcomes. By combining joint gap targets, subpopulations were identified with clinically significant improved pain outcomes. Furthermore, small changes in component alignment did not impact 1 yr pain outcomes, indicating soft tissue balance has a greater impact on outcome that alignment in the enrolled population. For any figures or tables, please contact the authors directly

Aims. The aims of this prospective study were to determine the effect of osteophyte excision on deformity correction and soft- tissue gap balance in varus knees undergoing total knee arthroplasty (TKA). Patients and Methods. Limb deformity in coronal (varus) and sagittal (flexion) planes, medial and lateral gap distances in maximum knee extension and 90° knee flexion and maximum knee flexion were recorded before and after excision of medial femoral and tibial osteophytes using computer navigation in 164 patients who underwent 221 computer-assisted, cemented, cruciate- substituting TKAs. Results. Mean varus and flexion deformities of 4.5°±3° (0.5° to 30° varus) and 4.9°±5.9° (−15° hyperextension to 30° flexion) reduced significantly (p<0.0001) to mean varus deformity of 1°±2.3° and mean flexion deformity of 2.7°±4.2° after excision of medial femoral and tibial osteophytes. The mean medio-lateral (ML) soft-tissue gap difference in maximum knee extension and 90°knee flexion of 2.7±3.6mm and 0.7±2.6mm reduced significantly (p<0.0001) to mean ML soft-tissue gap difference of 0.7±2.5mm in maximum knee extension and 0.1±1.9mm in 90°knee flexion. The mean maximum knee flexion (122.8°±8.4°) increased significantly to mean maximum knee flexion of (125°±8°). Conclusion. Excision of medial femoral and tibial osteophytes during TKA in varus knees significantly improves varus and flexion deformities, mediolateral soft-tissue gap imbalance in maximum extension and in 90°knee flexion and maximum knee flexion. Clinical Relevance. Excision of medial femoral and tibial osteophytes can be a useful, initial step towards achieving deformity correction and gap balance without having to resort to soft-tissue release during TKA in varus knees

Introduction. Soft-tissue balancing methods in TKA have evolved from surgeon feel to digital load-sensing tools. Such techniques allow surgeons to assess the soft-tissue envelope after bone cuts, however, these approaches are ‘after-the-fact’ and require soft-tissue release or bony re-cuts to achieve final balance. Recently, a robotic ligament tensioning device has been deployed which characterizes the soft tissue envelope through a continuous range-of-motion after just the initial tibial cut, allowing for virtual femoral resection planning to achieve a targeted gap profile throughout the range of flexion (figure-1). This study reports the first early clinical results and patient reported outcomes (PROMs) associated with this new technique and compares the outcomes with registry data. Methods. Since November 2017, 314 patients were prospectively enrolled and underwent robotic-assisted TKA using this surgical technique (mean age: 66.2 ±8.1; females: 173; BMI: 31.4±5.3). KOOS/WOMAC, UCLA, and HSS-Patient Satisfaction scores were collected pre- and post-operatively. Three, six, and twelve-month assessments were completed by 202, 141, and 63 patients, respectively, and compared to registry data from the Shared Ortech Aggregated Repository (SOAR). SOAR is a TJA PROM repository run by Ortech, an independent clinical data collection entity, and it includes data from thousands of TKAs from a diverse cross-section of participating hospitals, teaching institutions and clinics across the United States and Canada who collect outcomes data. PROMs were compared using a two-tailed t-test for non-equal variance. Results. When comparing the baseline PROM scores, robotic patients had equivalent womac knee stiffness (p=0.58) and UCLA activity scale (p=0.38) scores but slightly higher womac knee pain (p=0.002) and functional scores (p=0.014, figure-2). While all scores improved over time, the rate of improvement was generally greater at 6 months than at three months when comparing the two groups, with statistically higher six-month scores in the robotic group for all categories (p<0.001). Overall patient satisfaction in the RB cohort was 90.3%, 95.0% and 91.8% at 3M, 6M and 1Y, respectively (figure-3). Average length of hospital stay was 1.6 days (±0.8). Surgical complications in this cohort included one infection four months post-op, 6 post-operative knee manipulations, one pulmonary embolism and one wound dehiscence from a fall. Discussion. We postulated that the ability to use gap data prospectively under known loading conditions throughout the knee range-of-motion would allow femoral cut planning that resulted in optimum balance with fewer releases and better long-term results. While the study group patients had slightly higher baseline knee pain and function than registry patients and showed similar net improvements at the three-month mark, study patients showed significantly better improvements in all areas between three months and six months compared to registry data. WOMAC stiffness and UCLA activity scores were equal between the two groups at baseline and significantly improved at three months and six months. Better ligament balance may have significantly contributed to these gains and to the high rates of satisfaction reported in the study patients compared to the historical literature. Limitations to this study include the small number of patients and the lack of a closely matched control group. For any figures or tables, please contact authors directly

Glenoid exposure is the name of the game in total shoulder arthroplasty. I can honestly say that it took me more than 5 years but less than 10 to feel confident exposing any glenoid, regardless of the degree of bone deformity and the severity of soft-tissue contracture. This lecture represents the synthesis of my experience exposing some of the most difficult glenoids. The basic principles are performing extensive soft-tissue release, minimizing the anteroposterior dimension of the humerus by osteophyte excision, making an accurate humeral neck cut, having a plethora of glenoid retractors, and knowing where to place them. The ten tips, in reverse order of importance are: 10.) Tilt the table away from operative side—this helps face the surface of the glenoid, especially in cases of posterior wear, toward the surgeon. 9.) Have multiple glenoid retractors—these include a large Darrach, a reverse double-pronged Bankart, one or two blunt Homans, small and large Fukudas. 8.) Remove all humeral osteophytes before attempting to retract the humerus posteriorly to expose the glenoid—this helps to decrease the overall anteroposterior dimension of the humerus and allows for maximum posterior displacement of the humerus. 7.) Make an accurate humeral neck cut—even 5mm of extra humeral bone will make glenoid exposure difficult. 6.) Optimal humeral position—it has been taught that abduction, external rotation, and extension is the optimal position. It may vary with each case. Therefore, experiment with humeral rotation to find the position that allows maximum visualization. This is often the position that makes the cut surface of the humerus parallel to the surface of the glenoid. 5.) Optimal retractor placement—my typical retractor placement is a Fukuda on the posterior lip of the glenoid, a reverse double-pronged Bankart on the anterior neck of the scapula, and a blunt Homan posterosuperiorly. Occasionally, a second blunt Homan anteroinferiorly is helpful, particularly in muscular males with a large pectoralis major. 4.) Laminar spreader for lateral humeral displacement—this can be helpful for posterior capsulorrhaphy or for posterior glenoid bone grafting. 3.) Maximal humeral capsular release—the release of the anterior capsule from the humerus must go well past the 6 o'clock position and up the posterior surface of the humerus. This aides in humeral exposure but also allows for more posterior displacement of the humerus during glenoid exposure. 2.) Anteroinferior capsular release or excision—extensive anteroinferior release or excision (my preference), allows for maximal posterior humeral displacement and also restores external rotation. 1.) Posterior or posteroinferior capsular release—release of the posteroinferior corner of the capsule from the glenoid results in a noticeable increase in posterior humeral retractability. In cases without substantial posterior subluxation, extensive release of the entire posterior capsule is performed

The extent of soft-tissue release and the exact structures that need to be released to correct deformity and balance the knee has been a controversial subject in primary total knee arthroplasty. Asian patients often present late and consequently may have profound deformities due to significant bone loss and contractures on the concave side, and stretching of the collateral ligament on the convex side. Extra-articular deformities may aggravate the situation further and make correction of these deformities and restoration of ‘balance’ more arduous. These considerations do not apply if a hinged prosthesis is used, as may be warranted in an elderly, low-demand patient. However, in active, younger patients, it may be best to avoid use of excess constraint by balancing the soft-tissues and using the least constrained implant. Releasing collateral ligaments during TKA has unintended consequences such as the creation of significant mediolateral instability and a flexion gap which exceeds the extension gap; both of these may require a constrained prosthesis to achieve stability. We will show that soft-tissue balance can be achieved even in cases of severe varus, valgus, flexion and hyperextension deformities without collateral ligament release. The steps are: 1) Determining pre-operatively whether deformity is predominantly intra-articular or extra-articular, 2) Individualizing the valgus resection angle and bony resection depth, 3) Meticulous removal of osteophytes, 4) Reduction osteotomy, posteromedial capsule resection, sliding medial or lateral condylar osteotomy, extra-articular corrective osteotomy, 5) Compensating for bone loss, 6)Only rarely deploying a more constrained device. Case examples will be presented to illustrate the entire spectrum of varus deformities

Computer assisted total knee arthroplasty helps in accurate and reproducible implant positioning, bony alignment, and soft-tissue balancing which are important for the success of the procedure. In TKR, there are two surgical techniques one is measured resection in which bony landmarks are used to guide the bone cuts and the other is gap balancing which equal collateral ligament tension in flexion and extension is done before and as a guide to final bone cuts. Both these procedures have their own advantages and disadvantages. We retrospectively collected the data of 128 consecutive patients who underwent computer-assisted primary TKA using either a gap-balancing technique or measured resection technique. All the operations were performed by a single surgeon using computer navigation system available during a period between June 2016 to October 2016. Inclusion criteria were all patients requiring a primary TKA, male or female patients, and who have given informed consent for participation in the study. All patients requiring revision surgery of a previous implanted TKA or affected by active infection or malignancy, who presented hip ankylosis or arthrodesis, neurological deficit or bone loss or necessity of more constrained implants were excluded from the study. Two groups measured resection and gap balancing was randomly selected. At 1-year follow-up, patients were assessed by a single orthopaedic registrar blinded to the type of surgery using the Knee Society score (KSS) and functional Knee Society score (FKSS). Outcomes of the 2 groups were compared using the paired t test. All the obtained data were analysed. Statistical analysis was performed using SPSS 11.5 statistical software (SPSS Inc. Chicago). Inter-class correlation coefficient (ICC) and paired t-test were used and statistical significance was set at P = 0.05. In the measured resection group, the mean FKSS increased from 48.8769 (SD, 2.3576), to 88.5692 (SD, 2.7178) respectively. In the gap balancing group, the respective scores increased from 48.9333 (SD, 3.6577) to 89.2133(SD, 7.377). Preoperative and Postoperative increases in the respective scores were slightly better with the gap balancing technique; the respective p values were 0.8493 and 0.1045. The primary goal of TKA is restoration of mechanical axis and soft-tissue balance. Improper restoration leads to poor functional outcome and premature prosthesis loosening. Computer navigation enables precise femoral and tibial cuts and controlled soft-tissue release. Well balanced and well aligned knee is important for good results. Mechanical alignment and soft-tissue balance are interlinked and corrected by soft tissue releases and precise proximal tibial and distal femoral cuts. The 2 common techniques used are measured resection and gap balancing techniques. In our study, knee scores of the 2 groups at 1-year follow-up were compared, as most of the improvement occurs within one year, with very little subsequent improvement. Some surgeons favour gap balancing technique, as it provides more consistent soft-tissue tension in TKA

Introduction & Aims. The traditional method of soft-tissue balancing during TKA is subjective in nature, and stiffness and instability are common indications for revision, suggesting that TKA balancing by subjective assessment is suboptimal. This study examines the intraoperative mediolateral loads measured with a nanosensor-enabled tibial insert trial and the sequential balancing steps used to achieve quantitative balance. Data obtained from a prospective multicenter study was assessed to determine the effect of targeted ligament release on intra-articular loading, and to understand which types of releases are necessary to achieve quantified ligament balance. Methods. A group of 129 patients received sensor-assisted TKA, as part of a prospective multicenter study. Medial and lateral loading data were collected pre-release, during any sequential releases, and post-release. All data were collected at 10, 45, and 90 degrees during range of motion testing. Ligament release type, release technique type, and resultant loading were collected. Results. Measured loads consistently decreased after soft-tissue release or bony re-cut and the relative mediolateral loading became more symmetric. The average change in loading values were approximately the same whether release or pie-crusting techniques were employed. In order to achieve balance, exhibited through the range of motion, the medial compartment required, on average, over double the release to loading (lbf.) than the lateral compartment. Structural changes that contributed significantly to changes in loading were: Release of the anterior and posterior bands of the MCL, pes anserine release, and recutting the tibia. On average, 2 or 3 structural corrections were performed to achieve balance. Conclusions. The use of quantitative sensor data during TKA balancing enables targeted corrections to the soft-tissue envelope in order to correct intercompartmental load differential. 2–3 steps are needed on average to achieve soft tissue balance

Glenoid exposure is the name of the game in total shoulder arthroplasty. I can honestly say that it took me more than 5 years but less than 10 to feel confident exposing any glenoid, regardless of the degree of bone deformity and the severity of soft-tissue contracture. This lecture represents the synthesis of my experience exposing some of the most difficult glenoids. The basic principles are performing extensive soft-tissue release, minimizing the anteroposterior dimension of the humerus by osteophyte excision, making an accurate humeral neck cut, having a plethora of glenoid retractors, and knowing where to place them. The ten tips, in reverse order of importance are: 10.) Tilt the table away from operative side—this helps face the surface of the glenoid, especially in cases of posterior wear, toward the surgeon. 9.) Have multiple glenoid retractors—these include a large Darrach, a reverse double-pronged Bankart, one or two blunt Homans, small and large Fukudas. 8.) Remove all humeral osteophytes before attempting to retract the humerus posteriorly to expose the glenoid—this helps to decrease the overall anteroposterior dimension of the humerus and allows for maximum posterior displacement of the humerus. 7.) Make an accurate humeral neck cut—even 5mm of extra humeral bone will make glenoid exposure difficult. 6.) Optimal humeral position—it has been taught that abduction, external rotation, and extension is the optimal position. It may vary with each case. Therefore, experiment with humeral rotation to find the position that allows maximum visualization. This is often the position that makes the cut surface of the humerus parallel to the surface of the glenoid. 5.) Optimal retractor placement—my typical retractor placement is a Fukuda on the posterior lip of the glenoid, a reverse double-pronged Bankart on the anterior neck of the scapula, and a blunt Homan posterosuperiorly. Occasionally, a second blunt Homan anteroinferiorly is helpful, particularly in muscular males with a large pectoralis major. 4.) Laminar spreader for lateral humeral displacement—this can be helpful for posterior capsulorrhaphy or for posterior glenoid bone grafting. 3.) Maximal humeral capsular release—the release of the anterior capsule from the humerus must go well past the 6 o'clock position and up the posterior surface of the humerus. This aides in humeral exposure but also allows for more posterior displacement of the humerus during glenoid exposure. 2.) Anteroinferior capsular release or excision—extensive anteroinferior release or excision (my preference), allows for maximal posterior humeral displacement and also restores external rotation. 1.) Posterior or posteroinferior capsular release—release of the posteroinferior corner of the capsule from the glenoid results in a noticeable increase in posterior humeral retractability. In cases without substantial posterior subluxation, extensive release of the entire posterior capsule is performed. Following these steps will help the surgeon to gain adequate glenoid exposure, even in the most difficult cases

Introduction. Knee instability, stiffness, and soft-tissue imbalance are causes of aseptic revision and patient dissatisfaction following total knee arthroplasty (TKA). Surgical techniques that ensure optimal ligament balance throughout the range of motion may help reduce TKA revision for instability and improve outcomes. We evaluated a novel tibial-cut first gap balancing technique where a computer-controlled tensioner is used to dynamically apply a varying degree of distraction force in real-time as the knee is taken through a range of motion. Femoral bone cuts can then be planned while visualizing the predicted knee implant laxity throughout the arc of flexion. Surgical Technique Description. After registering the mechanical axes and morphology of the tibia and femur using computer navigation, the tibial resection was performed and a robotic tensioning tool was inserted into the knee prior to cutting the femur. The tool was programmed to apply equal loads in the medial and lateral compartments of the knee, but to dynamically vary the distraction force in each compartment as the knee is flexed with a higher force being applied in extension and a progressively lower force applied though mid-flexion up to 90° of flexion. The tension and predictive femoral gaps between the tibial cut and the femoral component in real-time was determined based on the planned 3D position and size of the femoral implant and the acquired pre-resection gaps (figure 1). Femoral resections were then performed using a robotic cutting guide and the trial components were inserted. Methods. The technique was evaluated by three experienced knee arthroplasty surgeons on 4 cadaver knees (3 torso-to-toe specimens, Pre-operative deformity range: 4° varus − 6° valgus; Extension lag: 0° – 13°; BMI 23.4 – 32.6; Age 68 – 85yr). An applied targeted load of 80N in extension and 50N in flexion was used in each of the four knees. These force values were determined in a prior cadaver study aimed at determining what magnitude of applied load corresponded to an optimally rated knee tension and stability. The femoral component was planned in each of the four knees to have symmetric gaps at 0° and 90° of flexion. The overall balance of the knee was assessed clinically by each surgeon using a varus/valgus stress test with the trial components inserted. No soft-tissue releases were performed other than a standard medial release during initial exposure of the knee. The following scale was used to rate the final knee stability achieved: 1 – too loose; 2 – slightly loose; 3 – ideal; 4 slightly tight; 5 – too tight. Results. ‘Ideal' balance was achieved in three out of the four knees tested (table 1). In two of the four knees the final inserted thickness selected was 1mm thicker than the planned insert thickness. Conclusions. Our preliminary cadaver results suggest that it is possible to achieve a balanced knee by incorporating dynamic ligament tensioning and gap data throughout flexion into the femoral planning process using a robotic tensioning tool. For figures/tables, please contact authors directly.