Recent advances in designs, approaches and materials in total knee replacement: literature review and evidence today

Mid-term outcomes of a kinematically designed cruciate retaining total knee arthroplasty

BACKGROUND

Advances in implant material and design have allowed for improvements in total knee arthroplasty (TKA) outcomes. A cruciate retaining (CR) TKA provides the least constraint of TKA designs by preserving the native posterior cruciate ligament. Limited research exists that has examined clinical outcomes or patient reported outcome measures (PROMs) of a large cohort of patients undergoing a CR TKA utilizing a kinematically designed implant. It was hypothesized that the studied CR Knee System would demonstrate favorable outcomes and a clinically significant improvement in pain and functional scores.

AIM

To assess both short-term and mid-term clinical outcomes and PROMs of a novel CR TKA design.

METHODS

A retrospective, multi-surgeon study identified 255 knees undergoing a TKA utilizing a kinematically designed CR Knee System (JOURNEY™ II CR; Smith and Nephew, Inc., Memphis, TN) at an urban, academic medical institution between March 2015 and July 2021 with a minimum of two-years of clinical follow-up with an orthopedic surgeon. Patient demographics, surgical information, clinical outcomes, and PROMs data were collected via query of electronic medical records. The PROMs collected in the present study included the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) and Patient-Reported Outcomes Measurement Information System (PROMIS®) scores. The significance of improvements in mean PROM scores from preoperative scores to scores collected at six months and two-years postoperatively was analyzed using Independent Samples t-tests.

RESULTS

Of the 255 patients, 65.5% were female, 43.8% were White, and patients had an average age of 60.6 years. Primary osteoarthritis (96.9%) was the most common primary diagnosis. The mean surgical time was 105.3 minutes and mean length of stay was 2.1 d with most patients discharged home (92.5%). There were 18 emergency department (ED) visits within 90 d of surgery resulting in a 90 d ED visit rate of 7.1%, including a 2.4% orthopedic-related ED visit rate and a 4.7% non-orthopedic-related ED visit rate. There were three (1.2%) hospital readmissions within 90 d postoperatively. With a mean time to latest follow-up of 3.3 years, four patients (1.6%) required revision, two for arthrofibrosis, one for aseptic femoral loosening, and one for peri-prosthetic joint infection. There were significant improvements in KOOS JR, PROMIS Pain Intensity, PROMIS Pain Interference, PROMIS Mobility, and PROMIS Physical Health from preoperative scores to six month and two-year postoperative scores.

CONCLUSION

The evaluated implant is an effective, novel design offering excellent outcomes and low complication rates. At a mean follow up of 3.3 years, four patients required revisions, three aseptic and one septic, resulting in an overall implant survival rate of 98.4% and an aseptic survival rate of 98.8%. The results of our study demonstrate the utility of this kinematically designed implant in the setting of primary TKA.

Outcomes of total hip arthroplasty surgery in heart and lung transplant recipients

BACKGROUND

Traditionally, arthroplasty in heart and lung transplant patients has been undertaken to manage transplant-related complications. More recently, arthroplasty is increasingly being performed for end-stage osteoarthritis. This study reviewed short-term outcomes and complications of total hip arthroplasty (THA) in heart and lung transplant recipients.

METHODS

A retrospective cohort of heart and lung transplant recipients who underwent THA was identified using ICD-10 coding. Post-operative complications and hospital outcomes were collected using the patient medical record.

RESULTS

Thirteen patients underwent 17 primary THA between 2008 and 2017, including five for osteoarthritis and 12 for femoral head avascular necrosis. Of the 13 patients, nine were bilateral sequential lung transplant recipients and four were orthotopic heart transplant recipients. The mean patient age was 61 years, with nine being male. Overall, five patients had one post-operative complication with eight having two or more complications. Surgical complications included three intraoperative fractures, three patients with superficial infection and one with deep infection requiring surgery. Seven patients had significant bleeding requiring blood transfusion. Prosthetic dislocations occurred in two patients, with one patient requiring revision surgery (developing a joint infection). Other complications included one pulmonary embolism, two episodes of pneumonia and six episodes of acute kidney injury, whilst three patients developed post-operative delirium. At 6-week follow-up, five patients had ongoing pain and seven had limitations with mobility. At 12-month follow-up, three patients reported ongoing pain.

CONCLUSION

Complications following THA after transplant are common. The risks and benefits of THA should be carefully considered preoperatively in this cohort.

Short term outcomes of long duration versus short duration tourniquet in primary total knee arthroplasty: A randomized controlled trial

INTRODUCTION

A tourniquet is used during the total knee replacement surgery to improve the visibility, to reduce the blood loss and for better cementation. Indirectly it decreases the duration of surgery and enhances the recovery of the patient. Their use however is controversial due to some side effects associated with the use of tourniquet. They may increase the risk of deep vein thrombosis and pulmonary embolism by causing venous stasis, endothelial damage and increased platelet adhesion secondary to distal limb ischemia.

MATERIAL AND METHODS

We conducted a randomized controlled trial (RCT) to examine the benefits and risks associated with the use of long duration over short duration tourniquets during TKA. The study was a prospective randomised control trial with a total of 80 knees (40 knees in each group) included in the study. The knees selected for surgery were randomly allocated to one of the two groups: Group A - long duration tourniquet (LT-group) or Group B - short duration tourniquet (ST-group).

RESULT

The average operating time in Group A (43.53±3.11 minutes) was statistically less significant than that of Group B (51.7±2.56 minutes). Intra-operative blood loss in Group B, was significantly more than that of Group A. Post-operative blood loss in the drain was more in long duration tourniquet group. Total blood loss (intra-operative + post-operative) was more in short duration tourniquet group. Pain score (using VAS scale) was comparable in both the groups at the end of the second and sixth week. At sixth weeks there was no significant difference in the range of motion in both the groups. The KSS score was not significantly different in both the groups in post operative period at first, second, and six weeks. There were no events of thrombo-embolism and deep vein thrombosis in either groups. In 11 patients (27.5%) of long duration tourniquet group, swelling, and redness of knee was seen post operatively as compared to three patients (7.5%) of short duration tourniquet group.

CONCLUSION

The use of a short duration tourniquet during TKA gives better symptomatic pain relief in the early postoperative period as compared to long duration use of tourniquet. However, this is associated with increased blood loss, more operating time and not having a clear operative field. We suggest that a rational thinking and reconsidering the practice of routine use of long duration tourniquet in each and every case of TKA is required.

Obesity Epidemic: Is Its Impact on Total Joint Arthroplasty Underestimated? An Analysis of National Trends

BACKGROUND

Obesity is a well-established risk factor for total joint arthroplasty (TJA) and a number of complications including prosthetic joint infection. The annual changes in the prevalence of obesity among primary, revision, and infected TJA has not been studied at a national level. Given the higher costs of complications of TJA, it is important to understand the association of obesity with the annual trends of revision and infected TJA.

QUESTIONS/PURPOSES

(1) Is the prevalence of obesity increasing among patients undergoing THA/TKA? (2) Is the prevalence of obesity increasing among patients undergoing revision THA/TKA? (3) Is the prevalence of obesity increasing among patients with infected THA/TKA?

METHODS

Annual volumes of primary, revision, and infected THA and TKA from 1998 to 2011 were obtained from the Nationwide Inpatient Sample. Using mathematical equations, the prevalence of obesity was estimated from relative risks and national obesity prevalence. National obesity prevalence was obtained from public health sources and the relative risk estimates were obtained from previously published meta-analyses and population-based studies. Annual prevalence of obesity was obtained by dividing the number of obese primary/revision/infected procedures in each year by the total number of corresponding procedures in that year. Annual changes in the prevalence of obesity were analyzed using linear regression.

RESULTS

The prevalence of obesity is increasing among patients undergoing THA (1998: 60,264 of 154,337 [39%], 2011: 160,241 of 305,755 [52%], increase of 1.05%/year [confidence interval {CI}, 0.95%-1.15%], p < 0.001) and TKA (1998: 143,681 of 251,309 [57%], 2011: 448,712 of 644,243 [70%], increase of 0.97%/year [CI, 0.87%-1.07%], p < 0.001). There was an increasing prevalence of obesity with THA revisions (1998: 16,322 of 34,139 [48%], 2011: 33,304 of 54,453 [61%], increase of 1.04%/year [CI, 0.94%-1.15%], p < 0.001) and in TKA revisions (1998: 16,837 of 26,539 [63%], 2011: 52,151 of 69,632 [75%], increase of 0.89%/year [CI, 0.79%-0.99%], p < 0.001). There was an increasing prevalence of obesity with THA infections (1998: 2068 of 3018 [69%], 2011: 6856 of 8687 [79%], increase of 0.80%/year [CI, 0.71%-0.89%], p < 0.001) and in TKA infections (1998: 3563 of 4684 [76%], 2011: 14,178 of 16,774 [85%], increase of 0.65%/year [CI, 0.57%-0.73%], p < 0.001).

CONCLUSIONS

The prevalence of obesity has increased in patients undergoing primary, revision, and infected TJA in United States. The obesity epidemic appears to be related to the growing trends of revision and infection after TJA. With the obesity rates expected to grow further, the revision and infection burden associated with obesity may increase in the future.

LEVEL OF EVIDENCE

Level II, prognostic study.

Evolution of TKA design

The use of Total Knee Arthroplasty (TKA) in treatment of chronic degenerative pathologies of the knee boasts of an experience of 50 years. During this period the collaboration between surgeons and engineers produced many developments in the design of the prosthesis. Today this procedure is safe and established even if in continuous development. The progress in technologies and the use of new materials let researches try again old-fashioned techniques from the past in order to be improved. This enthusiasm for those discovers is not always going hand to hand with scientific validation: many open questions remains Every different concept of the design tries to answer to special needs as the reach of the highest ROM, the reduction of pain and debris, articular geometry, the type of fixation, the modularity of augments and stems, the types of constraints,  knee kinematic and of course costs.

Bilateral Simultaneous Total Knee Arthroplasty: A Patient-Matched Retrospective Observational Study

Bilateral total knee arthroplasty can be performed either as a staged or simultaneous procedure. We conducted a retrospective comparative study to compare the need for transfusion, the length of procedure, the length of stay, and complications of bilateral simultaneous knee arthroplasty with those of unilateral knee arthroplasty. Sixty-nine patients who underwent bilateral simultaneous knee arthroplasty procedures were compared with a matched control group of 69 patients who underwent unilateral knee arthroplasty. Receiver Operating Characteristic (ROC) curve was used to determine optimum cut-off values. Both groups of patients had a similar age and gender distribution, preoperative haemoglobin and ASA scores. Cumulative transfusion episodes were lower in the bilateral group than twice that of the unilateral group. In multivariate analysis the preoperative haemoglobin level and bilateral procedures were independent factors predicting the need for transfusion. The average length of procedure and length of hospital stay in the bilateral group was less than twice than that of the unilateral group. Advanced age and bilateral procedures were independent predictors of prolonged length of stay. A haemoglobin level of 12.5 g/dL and age of 70 were most suitable cut-off points to predict need for transfusion and occurrence of medical complications respectively. We conclude that bilateral simultaneous knee arthroplasties are safe and cost effective in appropriately selected patients. We recommend avoiding bilateral simultaneous procedures in patients over the age of 70 years and with significant comorbidities.

Current Evidence for the Use of Laminar Flow in Reducing Infection Rates in Total Joint Arthroplasty

Since the introduction of laminar air flow in orthopaedic theatres by Sir John Charnley, it has widely become accepted as the standard during orthopaedic procedures such as joint arthroplasty. We present a review of available current literature for the use of laminar flow operating theatre ventilation during total joint arthroplasty and examines the effectiveness of laminar flow ventilated operating theatres in preventing post-operative wound infection. Results of our findings suggest that while bacterial and air particulate is reduced by laminar air flow systems, there is no conclusive effect on the reduction of post-operative wound infections following total joint arthroplasty. We conclude that a combination of strict aseptic technique, prophylactic antibiotics and good anaesthetic control during surgery remains crucial to reduce post-operative surgical infections.

Patella tendon injuries secondary to cement spacers used at first-stage revision of infected total knee replacement

We describe a series of three patients who sustained patella tendon injuries in infected total knee arthroplasties following the use of a static cement spacer at first-stage knee revision. The patella tendon injuries resulted in significant compromise to wound healing and knee stability requiring multiple surgeries. The mid-term function was poor with an Oxford score at 24 months ranging from 12 to 20. Based on our experience, we advise caution in the use of static cement spacer blocks. If they are to be used, we recommend that they should be keyed in the bone to prevent patella tendon injuries.

Preoperative predictors of pain following total knee arthroplasty

Total knee arthroplasty has provided dramatic improvements in function and pain for the majority of patients with knee arthritis, yet a significant proportion of patients remain dissatisfied with their results. We performed a prospective analysis of 215 patients undergoing TKA who underwent a comprehensive array of evaluations to discover whether any preoperative assessment could predict high pain scores and functional limitations postoperatively. Patients with severe pain with a simple knee range-of-motion test prior to TKA had a 10 times higher likelihood of moderate to severe pain at 6 months. A simple test of pain intensity with active flexion and extension preoperatively was a significant predictor of postoperative pain at 6 months after surgery. Strategies to address this particular patient group may improve satisfaction rates of TKA.

Current concepts in knee replacement: features and imaging assessment

OBJECTIVE

This article reviews current concepts of knee replacement. Features of traditional and new prosthetic designs, materials, and surgical techniques are discussed. Normal and abnormal postoperative imaging findings are illustrated. Complications are reviewed and related to the current understanding about how and why these failures occur.

CONCLUSION

It is well known that after knee replacement, patients with complications may be asymptomatic, and, for this reason, assessment of postoperative imaging is important. The foundation of radiologic interpretation of knee replacement is knowledge of the physiologic purpose, orthopedic trends, imaging findings, and complications.