Preoperative gait patterns and BMI are associated with tibial component migration

Background and purpose

There is no standard for patient triage in total knee arthroplasty (TKA) based on joint functional characteristics. This is largely due to the lack of objective postoperative measurement of success in TKA in terms of function and longevity, and the lack of knowledge of preoperative metrics that influence outcome. We examined the association between the preoperative mechanical environment of the patients knee joint during gait and the post-TKA stability of the tibial component as measured with radiostereometric analysis (RSA).

Methods

37 subjects were recruited out of a larger randomized RSA trial. 3-dimensional gait analysis was performed in the preoperative week. Longitudinal RSA data were gathered postoperatively at 6 months and 1 year.

Results

We found a statistically significant association between the pattern of the knee adduction moment during gait preoperatively and the total migration of the implant at 6 months postoperatively. A substantial proportion of the variability in the total postoperative tibial component migration (R² = 0.45) was explained by a combination of implant type, preoperative knee joint loading patterns during gait, and body mass index at 6 months postoperatively. The relationships did not remain statistically significant at 1 year postoperatively.

Interpretation

Our findings support the hypothesis that preoperative functional characteristics of patients, and particularly joint loading patterns during activities of daily living, are important for outcome in TKA. This represents a first step in the development of predictive models of objective TKA outcome based on preoperative patient characteristics, which may lead to better treatment strategies.ClinicalTrials.gov ({"type":"clinical-trial","attrs":{"text":"NCT00405379","term_id":"NCT00405379"}}NCT00405379)     

In vivo comparisons of patellofemoral kinematics before and after ADVANCE? Medial-Pivot total knee arthroplasty

Purpose

ADVANCE? Medial-Pivot (MP) (Wright Medical Technology, Arlington, TN, USA) total knee arthroplasty (TKA) was developed to replicate normal tibiofemoral knee joint kinematics, allowing medial-pivot knee motion. The design concept of the prosthesis is unique; therefore, the influence on the patellofemoral knee joint remains unclear at present. The purpose of this study was to determine the in vivo patellofemoral kinematics with ADVANCE? MP TKA and compare them with the pre-operative conditions.

Methods

ADVANCE? MP TKA was performed in ten subjects with osteoarthritis (OA). At before and one?month after surgery, lateral radiographs with weight-bearing at maximum extension, 30, 60 and 90° were taken, and patella flexion angle (PF), tibiopatellar angle (TP) and estimated patellofemoral contact point (PC) were evaluated, according to a previously reported method.

Results

In PF and TP, there was no statistically significant change between pre-operative and postoperative values. Pre-operative PC reached its peak at 90°; however, its peak was at 60° at one?month after surgery. Postoperative PC at maximum extension was significantly higher compared to before surgery.

Conclusions

The results in this study indicated that ADVANCE? MP TKA changed patellofemoral joint kinematics compared to before surgery. Early postoperative evaluation is the limitation of this study; however, we consider that the results in this study might be one of the keys to resolving the kinematic features of this prosthesis, helping clinicians to comprehend this prosthesis.     

Is There a Gold Standard for TKA Tibial Component Rotational Alignment?

Background

Joint function and durability after TKA depends on many factors, but component alignment is particularly important. Although the transepicondylar axis is regarded as the gold standard for rotationally aligning the femoral component, various techniques exist for tibial component rotational alignment. The impact of this variability on joint kinematics and stability is unknown.

Questions/purposes

We determined how rotationally aligning the tibial component to four different axes changes knee stability and passive tibiofemoral kinematics in a knee after TKA.

Methods

Using a custom surgical navigation system and stability device to measure stability and passive tibiofemoral motion, we tested 10 cadaveric knees from five hemicorpses before TKA and then with the tibial component aligned to four axes using a modified tibial tray.

Results

No changes in knee stability or passive kinematics occurred as a result of the four techniques of tibial rotational alignment. TKA produces a ‘looser’ knee over the native condition by increasing mean laxity by 5.2°, decreasing mean maximum stiffness by 4.5 N·m/°, increasing mean anterior femoral translation during passive flexion by 5.4 mm, and increasing mean internal-external tibial rotation during passive flexion by 4.8°. However, no statistically or clinically important differences occurred between the four TKA conditions.

Conclusions

For all tibial rotations, TKA increased laxity, decreased stiffness, and increased tibiofemoral motion during passive flexion but showed little change based on the tibial alignment.

Clinical Relevance

Our observations suggest surgeons who align the tibial component to any of the axes we examined are expected to have results consistent with those who may use a different axis.     

Die infizierte Knieprothese

Objective

Treatment of an early total knee arthroplasty (TKA) infection with the goal of salvaging the implant.

Indications

Early postoperative infections within the first 4 weeks. The acute hemtogenous infection of the knee joint with TKA and duration of symptoms for a maximum of 4 weeks.

Contraindications

Unsuitable for anesthesia, high acute infection with sepsis and risk for bacteremia with danger to life, large soft tissue damage where plastic surgery coverage is not possible.

Surgical technique

Arthrotomy, synovectomy, inlay removal, jet lavage, instillation of polyhexanide, new inlay, drainage and infusion–aspiration–drainage if necessary, wound closure with plastic surgery if necessary.

Postoperative management

Infusion–aspiration–drainage with polyhexanide for 3 days or drainage for 3 days. Continuous passive motion (CPM) with increasing range of motion (ROM) 0–0–30°. Removal of the drain after 5 days and mobilization with increasing ROM and full weight-bearing.

Results

The success rate for the salvage procedure is about 70?%.     

Total knee arthroplasty of the stiff knee: three hundred and four cases

Purpose

The purpose of this study was to analyse the results of total knee arthroplasty (TKA) in stiff knees (flexion ≤90° and/or flexion contracture ≥20°). Our hypothesis was that despite having poorer results than those obtained in a “standard” population and a high rate of complications, TKA was a satisfactory treatment in patients with osteoarthritis of the knee associated with significant stiffness.

Methods

Three hundred and four consecutive primary HLS TKAs (Tornier), whose data were prospectively collected between October 1987 and October 2012, were retrospectively analysed at a mean of 60 months (range, 12–239) postoperatively. Two groups, those with a “flexion contracture” and those with a “flexion deficit”, were assessed for postoperative range of motion (as integrated to the Knee Society score [KSS]), physical activity level and patient satisfaction.

Results

At the latest follow-up, range of motion was significantly improved, as was the KSS. Ninety-four percent of patients were satisfied or very satisfied, and activity levels were increased after surgery. The complication rate, however, was high in patients with a preoperative flexion deficit (17 %). Pain and residual stiffness were the most common complications.

Conclusion

TKA provides satisfactory results in patients with knee osteoarthritis associated with significant pre-operative stiffness. The surgical plan should be adapted to anticipate complications, which are particularly frequent in the presence of a flexion deficit.     

The effect of femoral component design on patellar tracking in total knee arthroplasty: Genesis II prosthesis versus Vanguard prosthesis

Introduction

The Genesis II knee system incorporates 3° of external rotation into the femoral component and the femoral component is implanted in neutral rotation to the femur. The purpose of this study was to compare patellar tracking of the Genesis II knee system with that of the Vanguard knee system, in which the femoral component is routinely implanted in a 3° externally rotated position to the posterior condylar axis (PCA) of the femur.

Materials and methods

One hundred consecutive knees scheduled to undergo total knee arthroplasty (TKA) were enrolled. Fifty knees underwent TKA with the posterior-stabilized (PS) Genesis II prosthesis and 50 knees underwent TKA with the PS Vanguard prosthesis. Rotation of the femoral component was calculated by measuring the acute angle between the transepicondylar axis (TEA) and the PCA on axial computed tomography (CT) images. The postoperative patellar tilt and displacement were compared between groups. The range of motion and Knee Society scores were also compared.

Results

Forty-eight knees in each group were followed up for 2 years. There was no difference in the angle between the PCA and the TEA on postoperative CT scans between the two designs. There was also no difference in patellar tracking between groups. Both the Genesis II and Vanguard knee systems showed good clinical results at 2 years postoperatively.

Conclusion

The patellar tracking of the Genesis II prosthesis was comparable to that of the Vanguard prosthesis.

Level of evidence

Prospective cohort study, Level II.     

Late Tourniquet Release and Drain Clamping Reduces Postoperative Blood Loss in Total Knee Arthroplasty

Background

Many studies have investigated the effect of tourniquet release time and closed suction drainage in total knee arthroplasty (TKA). However, controversy remains as to the advisability of preclosure tourniquet release and the advisability of closed suction drain use following total knee arthroplasty.

Questions/Purposes

The aim of the study was to investigate if there is a benefit of performing tourniquet release after skin closure, along with drain clamping, for the first 6h following TKA.

Methods

Ninety-six patients underwent TKA between May 2009 and April 2010. Fourteen of these were excluded because of systemic diseases and simultaneous bilateral TKA. Twenty-nine of these were excluded due to use of a patellar component and posterior cruciate ligament (PCL)-sacrificing systems. Thus, 53 patients that underwent PCL-retaining cemented TKA were reviewed retrospectively. In the control group (group C), the tourniquet was released before skin closure, an attempt at hemostasis was made, and a compressive bandage was applied. The drain was not clamped in these patients. The test group of 23 patients (group T) had tourniquet release after skin closure and after the compressive bandage was applied. The drain was clamped for the first 6h after surgery. The two groups were compared as to the amount of drained blood, postoperative change in hemoglobin, postoperative complications, and knee function.

Results

We found that drained blood and hemoglobin drop were significantly lower in group T compared with group C. There was no difference regarding postoperative complications and knee function.

Conclusion

We conclude that tourniquet release after skin closure and compressive dressing followed by 6h of drain clamping reduces postoperative blood loss in TKR surgery.     

Length of hospital stay with patient-dependent determination in bilateral scheduled staged total knee arthroplasty

Purpose

The purpose of this study was to approach the length of hospital stay (LOS) by patient-dependent determination and evaluate the effect of contralateral total knee arthroplasty (TKA) on LOS in patients with bilateral osteoarthritis undergoing staged bilateral TKAs.

Methods

One hundred sixty TKAs in 80 patients with bilateral osteoarthritis were evaluated by retrospective review of their medical records. All patients had scheduled staged bilateral TKA. We investigated the length of hospital stay in each TKA and the postoperative day when patients could perform walking and climbing up and down the stairs with one cane independently. Range of motion in each knee was also evaluated in preoperatively and before discharge. The median interval between the first and second surgeries was 12 months.

Results

The first and second TKAs showed a median LOS of 37 and 35 days, respectively, with no significant difference (n.s.). The median number of days before independently walking and climbing up and down the stairs with one cane were 8 and 16 after the first TKA and 7 and 15 after the second TKA, respectively, without significant differences (n.s. for walking, n.s. for stairs).

Conclusions

An initial TKA that results in good function might neither facilitate an earlier second rehabilitation nor decrease the LOS. Taking other factors such economics and local conditions that largely influence LOS into account, simultaneous bilateral TKAs might be an effective treatment for bilateral knee arthritis in properly selected patients in terms of decreasing the LOS.     

Utility of tibial tubercle osteotomy in the setting of periprosthetic infection after total knee arthroplasty

Purpose

This study reports radiographic and clinical treatment outcomes of tibial tubercle osteotomy (TTO) used for two-stage revision total knee arthroplasty (TKA) in the setting of periprosthetic infection.

Methods

Thirty-six patients with 51 TTOs used for infected TKA were retrospectively analysed from 2000 to 2010. In 15 of 36 patients, TTO was used in a sequential manner during both first and second stage procedures. The mean follow-up period was 57?months (range seven–126?months).

Results

The mean pre-operative range of knee motion was 40° (range 10–90°), and at latest follow-up it was 92° (range 50–140°). The Knee Society knee scores and function scores were 47 and 9 pre-operatively and 82 and 72 at latest follow-up, respectively. Bony union was achieved in all cases except one nonunion of an avulsion fragment of the osteotomy segment without functional deterioration.

Conclusions

TTO can be a useful extensile surgical approach for treatment of infected TKA with satisfactory clinical and radiographic outcomes.     

Trends 2001 to 2008 in incidence and immediate postoperative outcomes for major joint replacement among Spanish adults suffering diabetes

Objectives

To analyze the trend of incidence rates of primary total knee (TKA) and primary total hip arthroplasty (THA) due to osteoarthritis among Spanish adults suffering diabetes (type-1 and 2) from 2001 to 2008 and analyze in-hospital mortality (IHM), length of stay (LOS) and hospital charges compared with non-diabetic patients.

Methods

From the Spanish National Hospital Database, we selected 250,205 patients with TKA and 122,926 patients with THA; 12 and 9% of patients undergoing TKA and THA, respectively, were diabetes sufferers, of them, 1.6% was classified as type 1 in each procedure.

Results

Incidence of both procedures increased over the period, but diabetic patients had a larger increment compared with non-diabetic patients. The ratio of diabetes versus non-diabetes sufferers undergoing TKA increased from 0.10 in 2001 to 0.16 in 2008 and from 0.08 to 0.11 for THA. Unadjusted IHM was higher among type-2 diabetic adults in both procedures. IHM rate did not show a secular time trend among diabetic patients. LOS was significantly longer among patients with diabetes type-1 and 2 undergoing THP when compared with non-diabetic patients. Hospital charges were higher among diabetic versus non-diabetic patients for both procedures showing a significant increase over the period.

Conclusions

Immediate postoperative outcomes for major joint replacement are worse among persons with than without diabetes, and prevalence of diabetes is increasing in patients undergoing these surgeries.     

Knee strength retention and analgesia with continuous perineural fentanyl infusion after total knee replacement: randomized controlled trial

Purpose

Despite providing adequate pain relief, a femoral nerve block can induce postoperative muscle weakness after total knee arthoplasty (TKA). Fentanyl has been shown to have peripheral effects but has not been used as a perineural infusate alone after TKA.

Methods

Sixty patients scheduled for TKA were randomized to one of three blinded groups: a continuous 24 h infusion of either fentanyl 3 μg/ml, ropivacaine 0.1 %, or 0.9 % normal saline through a femoral nerve sheath catheter at 10 ml/h. The main outcome was maximum voluntary isometric contraction (MVIC) in the quadriceps femoris (knee extension), measured by a handheld dynamometer (Nm/kg). Other variables assessed were preoperative and postoperative visual analog scale (VAS) scores, hamstrings MVIC (knee flexion), active range of motion of the operative knee, distance ambulated, incidence of knee buckling, supplemental morphine usage, postoperative side effects, and serum fentanyl levels.

Results

Quadriceps MVIC values were significantly greater in the fentanyl group compared to the group that received ropivacaine (median values, 0.08 vs. 0.03 Nm/kg; p = 0.028). The incidence of postoperative knee buckling upon ambulation was higher in the ropivacaine group compared to the fentanyl group, although not statistically significant (40 % vs. 15 %, respectively; p = 0.077). VAS scores while ambulating were not significantly different between the fentanyl group and the ropivacaine group (p = 0.270). Postoperative morphine consumption, nausea and vomiting, and resting VAS scores were similar among the three groups.

Conclusions

A continuous perineural infusion of fentanyl produced greater strength retention than ropivacaine post-TKA.     

In vivo function of posterior cruciate ligament before and after posterior cruciate ligament-retaining total knee arthroplasty

Purpose

The object of this study was to investigate the in vivo function of the posterior cruciate ligament (PCL) in patients before and after a PCL-retaining total knee arthroplasty (TKA).

Methods

Eleven patients with advanced osteoarthritis (OA) of the knee were recruited. Magnetic resonance scans of each OA knee were obtained, and 3D computer models, including the femoral and tibial insertion areas of the anterolateral and posteromedial bundles of the PCL, were created. Before and after PCL-retaining TKA, dual fluoroscopic images of each knee were acquired during weight-bearing knee flexion. The images and computer models were used to reproduce the in vivo motion of the knee. The function of the PCL bundles was described in terms of elongation, elevation and deviation. Twenty-two healthy controls were also included as normal references.

Results

PCL bundles of the OA knees were overstretched during late knee flexion and orientated more medially throughout flexion compared with normal knees. After PCL-retaining TKA, PCL bundles were further overstretched during late flexion and changed from medially directed in normal and OA knees to almost sagittally directed, which may compromise function in controlling knee rotation.

Conclusions

The current PCL-retaining TKA systems and surgical techniques may not adequately re-establish normal biomechanics of PCL bundles after PCL-retaining TKA.     

The efficacy of patellar decompression for improving anterior knee pain following total knee arthroplasty without patellar resurfacing

Background

Anterior knee pain remains common following total knee arthroplasty (TKA). In this study, we evaluated the efficacy of patellar decompression via drilling for the treatment of anterior knee pain following TKA without patellar resurfacing.

Methods

A prospective cohort study was performed in 271 consecutive patients who underwent primary total knee replacement with patellar decompression (study group, n = 131) or without decompression (control group, n = 140). The patients were assessed according to the Knee Society rating, clinical anterior knee pain score, and British Orthopaedic Association patient-satisfaction score in each group. Each assessment was performed without the examiner knowing whether the patella had been decompressed. Radiographic evaluations were also performed according to the Knee Society scoring system for functional activity and our own severity grade system for patellofemoral articular change.

Results

There were no adverse events following patellar decompression. The overall prevalence of anterior knee pain was not significantly different between groups (p = 0.71). However, patients presenting pain over grade II after the operation in the study group were statistically low (p = 0.01). The overall postoperative knee scores were higher in the study group, but there were no significant differences between groups (p = 0.0731). Analyses of the radiographs revealed similar postoperative outcomes in both groups of knees.

Conclusions

As we observed significantly lower rates of anterior knee pain and no patellar complications following patellar decompression via drilling in TKA without patellar resurfacing, we recommend performing patellar decompression in cases of total knee replacement without patellar resurfacing.