Gap Balancing Sacrifices Joint-Line Maintenance to Improve Gap Symmetry: A Randomized Controlled Trial Comparing Gap Balancing and Measured Resection

A total knee arthroplasty can be completed using two techniques; measured resection or gap balancing. A prospective blinded randomized controlled trial was completed with 103 patients randomized to measured resection (n=52) or gap balancing (n=51). Primary outcome measure was femoral component rotation. Secondary outcome measures were joint-line change, gap symmetry and function and quality-of-life outcomes. Gap balancing resulted in a significantly raised joint-line compared to measured resection. Gap symmetry was significantly better using gap balancing. Functional outcomes and quality-of-life were not significantly different at 24 months. Using computer navigation, gap balancing significantly raises the joint-line in order to improve gap symmetry. This does not result in a clinical difference in function or quality of life at 24 months.     

Contact Kinematic Differences Between Gap Balanced vs Measured Resection Techniques for Single Radius Posterior-Stabilized Total Knee Arthroplasty

Background

Measured resection (MR) and gap balancing (GB) are common surgical techniques for total knee arthroplasty (TKA). Controversy has arisen as each conceptually differs in how the knee is balanced through bone and soft tissue management. The objective of the present study was to compare both the frequency of condylar liftoff and the location of femorotibial contact from extension through midflexion between patients undergoing GB or MR TKA.

Gap Balancing vs. Measured Resection Technique in Total Knee Arthroplasty

A goal of total knee arthroplasty is to obtain symmetric and balanced flexion and extension gaps. Controversy exists regarding the best surgical technique to utilize to obtain gap balance. Some favor the use of a measured resection technique in which bone landmarks, such as the transepicondylar, the anterior-posterior, or the posterior condylar axes are used to determine proper femoral component rotation and subsequent gap balance. Others favor a gap balancing technique in which the femoral component is positioned parallel to the resected proximal tibia with each collateral ligament equally tensioned to obtain a rectangular flexion gap. Two scientific studies have been performed comparing the two surgical techniques. The first utilized computer navigation and demonstrated a balanced and rectangular flexion gap was obtained much more frequently with use of a gap balanced technique. The second utilized in vivo video fluoroscopy and demonstrated a much high incidence of femoral condylar lift-off (instability) when a measured resection technique was used. In summary, the authors believe gap balancing techniques provide superior gap balance and function following total knee arthroplasty.     

Comparison of Gap Balancing vs Measured Resection Technique in Patients Undergoing Simultaneous Bilateral Total Knee Arthroplasty: One Technique per Knee

BackgroundTotal knee arthroplasty requires careful surgical technique to attain the goal of a well-aligned and symmetrically balanced knee. Soft tissue balance and correct femoral component rotation are paramount in achieving these goals. The two competing techniques to select femoral component rotation and soft tissue balance are the gap balance technique and the measured resection technique.MethodsWe performed a randomized, prospective study to compare the two techniques in patients undergoing simultaneous bilateral total knee arthroplasty, whereby one technique was performed in each knee. Fifty (50) subjects were enrolled into the study. The inclusion criteria were osteoarthritic varus knee deformities with similar deformities in both knees. Subjects were followed up for a minimum of two years.ResultsThe knees balanced via the gap balance technique had significantly more posterior medial bone removed from the femur than those knees balanced via the measured resection technique (P < .001). Knees in the gap balance group tended to require more medial knee releases in extension and tended to have smaller sized femoral components as a result of cutting more bone from the femur in flexion. The modular tibial polyethylene bearing tended to be thicker in the gap balance group. Despite these differences, average knee flexion and functional revised Oxford Knee Scores at 2-year follow-up were not statistically different.ConclusionAt 2-year follow-up, there were no differences between the function and scores using the two techniques. Long-term follow-up will be necessary to evaluate any differences in long-term durability.     

Randomized Controlled Trial of Sensor-Guided Knee Balancing Compared to Standard Balancing Technique in Total Knee Arthroplasty

BackgroundDespite advances in total knee arthroplasty (TKA) technology, up to 1 in 5 patients remain dissatisfied. This study sought to evaluate if sensor-guided knee balancing improves postoperative clinical outcomes and patient satisfaction compared to a conventional gap balancing technique.MethodsWe undertook a prospective double-blind randomized controlled trial of patients presenting for elective primary TKA to determine a difference in TKA soft tissue balance between a standard gap balancing (tensiometer) approach compared to augmenting the balance using a sensor-guided device. The sensor-guided experimental group had adjustments made to achieve a balanced knee to within 15 pounds of intercompartmental pressure difference. Secondary outcomes included differences in clinical outcome scores at 6 months and 1 year postoperative, including the Oxford Knee Score and Knee Society Score and patient satisfaction.ResultsThe sample comprised of 152 patients, 76 controls and 76 experimental sensor-guided cases. Within the control group, 36% (27/76) of knees were unbalanced based on an average coronal plane intercompartmental difference >15 pounds, compared to only 5.3% (4/76) within the experimental group (P < .0001). There were no significant differences in 1-year postoperative flexion, Knee Society Score, or Oxford scores. Overall, TKA patient satisfaction at 1 year was comparable, with 81% of controls and experimental cases reporting they were very satisfied (P = .992).ConclusionDespite the use of the sensor-guided knee balancer device to provide additional quantitative feedback in the evaluation of the soft tissue envelope during TKA, we were unable to demonstrate improved clinical outcomes or patient satisfaction compared to our conventional gap balancing technique.     

Neither Anterior nor Posterior Referencing Consistently Balances the Flexion Gap in Measured Resection Total Knee Arthroplasty: A Computational Analysis

Background

Whether anterior referencing (AR) or posterior referencing (PR) produces a more balanced flexion gap in total knee arthroplasty (TKA) using measured resection remains controversial. Our goal was to compare AR and PR in terms of (1) medial and lateral gaps at full extension and 90° of flexion, and (2) maximum medial and lateral collateral ligament (MCL and LCL) forces in flexion.

A Prospective Randomized Controlled Trial Comparing Medial-Pivot versus Posterior-Stabilized Total Knee Arthroplasty

BackgroundThe medial-pivot (MP) design for total knee arthroplasty (TKA) aims to restore more natural “ball-and-socket” knee kinematics compared to the traditional posterior-stabilized (PS) implants for TKA. The objective of this study is to determine if there was any difference in functional outcomes between patients undergoing MP-TKA vs PS-TKA.MethodsThis prospective randomized controlled trial consisted of 43 patients undergoing MP-TKA vs 45 patients receiving a single-radius PS-TKA design. The primary outcome was postoperative range of motion (ROM). Secondary outcomes included the Western Ontario and McMaster Universities Arthritis Index, Oxford Knee Score, Knee Society Score (KSS), and radiological outcomes. All study patients were followed-up for 2 years after surgery.ResultsPatients undergoing MP-TKA had comparable ROM at 1 year (114.6° ± 16.3° vs 111.3° ± 17.8° respectively, P = .88) and 2 years after surgery (114.9° ± 15.5° vs 114.9° ± 16.4° respectively, P = .92) compared to PS-TKA. There were also no differences in Western Ontario and McMaster Universities Arthritis Index (26.8 ± 19.84 vs 22.0 ± 12.03 respectively, P = .14), Oxford Knee Score (42.7 ± 8.1 vs 42.3 ± 6.7 respectively, P = .18), KSS clinical scores (82.9 ± 16.96 vs 81.42 ± 10.45 respectively, P = .12) and KSS functional scores (76.2 ± 18.81 vs 73.93 ± 8.53 respectively, P = .62) at 2-year follow-up. There was no difference in postoperative limb alignment or complications.ConclusionThis study demonstrated excellent results in both the single-radius PS-TKA design and MP-TKA design. No differences were identified at 2-year follow-up with respect to postoperative ROM and patient-reported outcome measures.     

Gap Balancing Sacrifices Joint-Line Maintenance to Improve Gap Symmetry: 5-Year Follow-Up of a Randomized Controlled Trial

Background

Gap balancing (GB) has been noted to sacrifice joint-line maintenance to improve gap symmetry. This study aims to determine whether this change affects function or quality of life in the midterm.

Reduction in Bone Volume Resection with a Newer Posterior Stabilized Total Knee Arthroplasty Design

Background

Posterior stabilized total knee arthroplasty requires an intercondylar notch to accommodate the cam housing that articulates with the tibial post to create femoral rollback required for deep flexion. The volume of bone resected for the intercondylar notch varies with implant design, and newer designs may accommodate high flexion with less bone resection.

Questions/Purposes

This study aims to analyze the bone volume and density resected from the intercondylar notch for three posterior stabilized implants from a single company: a Posterior Stabilized (PS) system, a Hi-Flex system (HF), and a rounded new box-reamer (RB) system and to further assess whether the newer RB with a cylindrical cutting tool would preserve more native bone.

Materials and Methods

Using a computer model, the PS, HF, and RB femoral components were digitally implanted into CT scans of 19 cadaver femurs. Nine cadavers were fit with a size 4 implant, six with size 3, and four with a size 2. The volume of intercondylar bone resected digitally for femoral preparation was measured. Bone density was measured by CT scans in Hounsfield units (HU). A paired t test was used to compare the mean volume of bone resected for each implant.

Results

For the size 4 femurs, the newer RB design removed 8% less intercondylar bone than the PS design (7,832 ± 501 vs. 8,547 ± 377 mm³, p < 0.001) and 28% less bone than the HF design (7,832 ± 501 vs. 10,897 ± 444 mm³, p < 0.001). The average HU for size 4 femurs for RB design was 427 ± 72 (PS = 399 ± 69, p < 0.001; HF = 379 ± 66, p < 0.001). For the size 3 femurs, the RB design removed 12% less intercondylar bone than the PS (6,664 ± 786 vs. 7,516 ± 648 mm³, p < 0.001) and 27% less bone than the HF (6,664 ± 786 vs. 9,078 ± 713 mm³, p < 0.001). HU for size 3 femurs for the RB design was 452 ± 70 (PS = 422 ± 53, p < 0.1; HF = 410 ± 59, p < 0.01). For the size 2 femurs, the RB design removed 5% less intercondylar bone than the PS (5,730 ± 552 vs. 6,009 ± 472 mm³, p < 0.01) and 22% less bone than the HF (5,730 ± 552 vs. 7,380 ± 532 mm³, p < 0.001). HU for size 2 femurs for the RB design was 430 ± 48 (PS = 408 ± 55, p < 0.01; HF = 385 ± 56, p < 0.01).

Conclusions

The newer RB design removes less bone from the intercondylar notch than the classic PS and HF designs in all sizes tested. The bone-conserving cuts incorporated into this newer implant design appear to preserve native bone without compromising design objectives.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-013-9340-1) contains supplementary material, which is available to authorized users.     

Total Knee Arthroplasty Using Bicruciate-Stabilized or Posterior-Stabilized Knee Implants Provided Comparable Outcomes at 2 Years: A Prospective,Multicenter, Randomized,Controlled, Clinical Trial of Patient Outcomes

Background

The bicruciate-stabilized (BCS) knee arthroplasty was developed to replicate normal knee kinematics. We examined the hypothesis that patients with osteoarthritis requiring total knee arthroplasty (TKA) will have better functional outcome and satisfaction with the BCS implant compared with an established posterior cruciate-stabilized implant.

Multimodal Nutritional Management in Primary Total Knee Arthroplasty: A Randomized Controlled Trial

Background

This study aims at evaluating the effectiveness of a new multimodal nutritional management (MNM) on albumin (ALB) transfusion, the incidence of electrolyte disorders, blood loss, perioperative levels of ALB and electrolyte, length of hospital stay (LOH), and complications in patients following total knee arthroplasty without tourniquet.

Second-Generation Electronic Ligament Balancing for Knee Arthroplasty: A Cadaver Study

Background

Knee instability is emerging as a major complication after total knee arthroplasty (TKA), with ligament laxity and component alignment listed as important contributory factors. Knee balancing remains an art and is largely dependent on the surgeon's subjective “feel.” The objectives were to measure the accuracy of an electronic balancing device to document the magnitude of correction in knee balance after soft-tissue releases and measure change in knee laxity after medial release.

Effects of Resection of Posterior Condyles of Femur on Extension Gap of Knee Joint in Total Knee Arthroplasty

Background

When evaluating the effects of the preparation of the flexion gap on the extension gap in total knee arthroplasty (TKA), the effects of posterior condylar resection and osteophyte removal on the extension gap should be differentiated. Although the amount of osteophytes differs between patients, posterior condylar resection is a procedure that is routinely implemented in TKA. The aim of this study was to assess the effects of the resection of the posterior condyle of the femur on the extension gap in posterior-stabilized (PS) TKA.

Patellar Denervation Reduces Postoperative Anterior Knee Pain After Patellar Resurfacing Total Knee Arthroplasty: A Randomized Controlled Trial

BackgroundThe benefit of patellar denervation (PD) in patellar resurfacing total knee arthroplasty (TKA) is still debatable. This prospective, randomized controlled trial investigated whether circumferential PD should be performed in patellar resurfacing TKA.MethodsA total of 241 patients who underwent unilateral TKA were randomized into PD or non-PD groups. Incidence, intensity, and presentation time of anterior knee pain (AKP) and clinical outcomes were evaluated at 3, 6, 9, 12, 18, and 24 months postoperatively.ResultsThe incidence of AKP was significantly lower in the PD group (6.4% vs 16.2%, P = .032). The intensity of AKP and patient satisfaction scores were significantly better in the PD group at 3 months but not after 3 months. The presentation time of AKP mostly occurs at 3 months after surgery. The Knee Society score, range of motion, Oxford score, patellar score, activity of daily living score, and visual analog scale of overall knee pain were not significantly different between the two groups during the follow-up period.ConclusionGiven that PD can improve AKP and patient satisfaction at an early period postoperatively without jeopardizing clinical outcomes at no additional cost, this inexpensive procedure readily available in nearly every operation room is strongly recommended during primary TKA with patellar resurfacing.     

Computer-Assisted Kinematic and Mechanical Axis Total Knee Arthroplasty: A Prospective Randomized Controlled Trial of Bilateral Simultaneous Surgery

BackgroundRandomized controlled trials of kinematic alignment (KA) and mechanical alignment (MA) in primary total knee arthroplasty (TKA) have to date demonstrated at least equivalence of KA in terms of clinical outcomes. No trial of bilateral TKA has been conducted so patient preference for one technique over the other is unknown.MethodsForty-one participants underwent computer-assisted bilateral TKA. The outcome measures were as follows: (1) joint range of motion and functional scores including the KOOS, the KOOS JR, Oxford Knee Score, and the Forgotten Joint Score at a minimum of 2 years; (2) preference and perception of limb symmetry; (3) intraoperative alignment data; (4) release and gap balance data; and (5) postoperative radiographic joint angles.ResultsThere were no significant differences with respect to flexion range (P = .970) or functional scores (mean KOOS, P = .941; KOOS JR, P = .685; Oxford Knee Score, P = .578; FJS, P = .542). Significantly more participants who favored one knee preferred their KA TKA (P = .03); however, half of the patients had no preference and the overall numbers were small. Only 3 participants perceived any limb asymmetry (P < .001). More releases were required in the MA group (P = .018). Standing hip-knee-ankle angle means and frequency distributions were similar (P = .097 and P = .097, respectively).ConclusionClinical outcomes were equivalent at 2 years. Significantly more participants preferred their KA joint. Fewer releases were required using a KA technique. Participants were visually insensitive to modest hip-knee-ankle angle asymmetry.Level of EvidenceLevel 1.     

Effect of an e-Learning Tool on Expectations and Satisfaction Following Total Knee Arthroplasty: A Randomized Controlled Trial

Background

Orthopedic surgeons recognize patient expectations of total knee arthroplasty (TKA) can be managed through education. E-learning is the application of educational technology. The objective of this study was to evaluate whether an e-learning tool could affect whether patients’ expectations were met and they were satisfied 1 year following TKA.

Effect of Tourniquet Use on Patient Outcomes After Cementless Total Knee Arthroplasty: A Randomized Controlled Trial

BackgroundTourniquet use is common in total knee arthroplasty (TKA), but debate exists regarding its use and effect on patient outcomes. The study purpose was to compare the effect of short tourniquet (ST) time vs long tourniquet (LT) time on pain, opioid consumption, and patient outcomes.MethodsPatients were prospectively randomized to an ST time of 10 min vs LT time. A total of 100 consecutive patients undergoing primary cementless robotic-assisted TKA underwent randomization, with 5 patients unable to complete follow-up, leaving 49 in the ST group and 46 in the LT cohort. Visual analog scale pain scores, morphine equivalent, serum creatine kinase, distance walked, range of motion, length of stay (LOS), surgical time, hemoglobin (Hgb), and Knee Society Scores (KSS) were prospectively collected.ResultsVisual analog scale pain was statistically equivalent at 24, 48, and 72 hours and at 2 and 6 weeks postoperatively. Morphine equivalent consumption was 36 vs 44 (P = .03), 48 vs 50 (P = .72), 31 vs 28 (P = .57), and 4.7 vs 5.5 (P = .75) in the LT vs ST cohorts at 24 hours, 48 hours, 2weeks, and 6weeks postoperatively. Change in Hgb postoperative day 1 was 2.7 in both groups (P = .975). Postoperative day 1 creatine kinase-MB was 3.7 and 3.0 (P = .30) in LT and ST cohorts. Six-week postoperative KSS Knee and Function scores were 82.4 and 70.5 in LT group vs 80.8 and 72.3 in ST group (P = .61 and P = .63). Postoperative range of motion, LOS, and surgical time were equivalent.ConclusionThis study demonstrates no significant advantage of ST use in primary TKA with respect to opioid consumption, patient-reported pain, KSS scores, LOS, or postoperative Hgb level.     

A Randomized Controlled Trial of Intraarticular Ropivacaine for Pain Management Immediately Following Total Knee Arthroplasty

Total knee arthroplasty (TKA) is a commonly performed procedure for the treatment of end-stage arthritis of the knee. Pain control following TKA is difficult to manage in some patients. We examined the use of a postoperative intraarticular injection of 100 mL of 0.2% (200 mg) ropivacaine in a double-blind, prospective, placebo-controlled pilot study to evaluate its use as a pain control modality. All patients received general anesthesia. Postoperatively, patients were placed on intravenous patient-controlled analgesia with morphine. The ropivacaine group showed an early trend in lower visual analog scale (VAS) scores when compared with the placebo group. Patients receiving ropivacaine used a similar amount of narcotics compared with the placebo group. Intraarticular ropivacaine used for pain control after TKA demonstrated no statistically significant difference in lowering VAS scores or narcotic usage; therefore, intraarticular ropivacaine as a single modality is not recommended for effective pain management.