Does circumpatellar electrocautery improve the outcome after total knee replacement?: a prospective, randomised, blinded controlled trial

Does Patellar Denervation with Electrocautery Benefits for Total Knee Arthroplasty without Patellar Resurfacing: A Meta-analysis of Randomized Controlled Trails

To investigate the effects of patellar denervation (PD) and non-patellar denervation (NPD) after primary total knee arthroplasty (TKA) without patellar resurfacing, this study conducted systematic electronic searches in November 2023 using PubMed, Embase, Web of Science, Cochrane, and Scopus, adhering to Cochrane Collaboration recommendations. Only randomized controlled trials (RCTs) were included. Additionally, a manual search was performed to identify potentially eligible studies from the reference lists of review articles. Two researchers independently conducted literature reviews, data extraction, and risk of bias assessments. The outcome analysis encompassed the incidence of anterior knee pain (AKP), visual analogue scale (VAS), range of motion (ROM), American Knee Society Score (KSS), Oxford Knee Score (OKS), patellar score (PS), complications, and reoperations. Meta-analysis was executed using RevMan 5.3 software. To enhance the credibility of the study, TSA v0.9 software was utilized to perform power analysis on the overall efficacy of primary and secondary outcomes. Twelve studies involving 1745 patients (1587 knees) were included, with 852 undergoing PD and 893 undergoing NPD. Results indicated a superior reduction in AKP incidence in the PD group compared to the NPD group. Statistically significant differences were observed between PD and NPD in KSS, OKS, and PS. However, the upper limit of the 95% confidence interval for each outcome fell below the minimal clinically important difference (MCID). No significant differences were found in VAS and ROM between PD and NPD. Additionally, PD was not associated with an increased incidence of complications or reoperations. Within 12 months and beyond, PD was proven to be a beneficial intervention in reducing AKP following TKA without patellar resurfacing, achieved without an increase in complications or reoperations. Regarding KSS, OKS, and PS, the minimal advantage achievable through PD may not be clinically significant.

Different modalities of patellar management in primary total knee arthroplasty: a Bayesian network meta-analysis of randomized controlled trials

BACKGROUND

The primary management modalities for the patella in TKA include patellar resurfacing, patellar non-resurfacing, patellar resurfacing with denervation, and patellar non-resurfacing with denervation. Traditionally, meta-analyses have predominantly focused on examining comparisons between two management modalities. However, this study performed a network meta-analysis to compare all four patellar management interventions to identify the most optimal approach for patellar management in TKA.

METHODS

A computer-based search of PubMed, China National Knowledge Infrastructure (CNKI), The Cochrane Library, Web of science, Embase, and MEDLINE databases was performed to identify randomized controlled trials focusing on the four management interventions for the patella in TKA. Comparisons included two-by-two comparisons as well as those involving more than two concurrent comparisons. The search timeframe spanned from inception to June 30, 2023. Two independent authors extracted the data and evaluated the quality of the literature. The Cochrane Collaboration Risk of Bias (ROB) tool was used to evaluate the overall quality of the literature. Subsequently, a network meta-analysis was conducted using the "gemtc" package of the R-4.2.3 software. Outcome measures such as anterior knee pain (AKP), reoperation rate, and patient satisfaction rate were evaluated using odd ratio (OR) and 95% confidence intervals (CI). Additionally, the knee society score (KSS), function score (FS), and range of motion (ROM) were evaluated using mean differences (MD) with associated 95% CI. The different treatment measures were ranked using the surfaces under the cumulative ranking curves (SUCRA).

RESULTS

A total of 50 randomized controlled trials involving 9,283 patients were included in the analysis. The findings from this network meta-analysis revealed that patellar resurfacing exhibited significantly lower postoperative reoperation rate (OR 0.44, 95% CI 0.24-0.63) and AKP (OR 0.58, 95% CI 0.32-1) compared to non-resurfacing. Additionally, patellar resurfacing exhibited higher postoperative KSS clinical scores in comparison with non-resurfacing (MD: 1.13, 95% CI 0.18-2.11). However, for postoperative FS, ROM, and patient satisfaction, no significant differences were observed among the four management interventions.

CONCLUSION

Patellar resurfacing emerges as the optimal management modality in primary TKA. However, future studies should aim to reduce sources of heterogeneity and minimize the influence of confounding factors on outcomes.

SYSTEMATIC REVIEW REGISTRATION

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023434418 identifier: CRD42023434418.

What can we expect from patellar denervation in knee arthroplasty? An updated systematic review and meta-analysis

Denervation by electrocauterization was proposed to be efficient in preventing anterior knee pain (AKP) following arthroplasty. The purpose of this study was to evaluate the effects of patellar denervation (PD) in primary knee arthroplasty. Systematic search was performed in PubMed, ScienceDirect, Cochrane Library, and ClinicalKey databases until July 2022 for published articles. The quantitative analyses were carried out by Review Manager 5.4 software. Twenty-one studies were included. Overall incidence of AKP, visual analog scale (VAS), and knee society score were significantly superior in PD group. Denervation also showed better outcomes in incidence of AKP at each follow-up time point, and in VAS and range of motion (ROM) at ≤3 months. Subanalyses based on depth of electrocautery showed statistically better results with 2–3 mm depth in VAS and PS compared to ≤1 mm. This study concluded that PD might contribute to lower incidence of knee pain. Patients who expect quicker recovery in pain and ROM may benefit from this procedure.

Patellar denervation does not reduce post-operative anterior knee pain after primary total knee arthroplasty with patellar resurfacing

PURPOSE

Anterior knee pain (AKP) is a frequent symptom after a total knee arthroplasty (TKA). Patellar denervation (PD) has been put forth as a technique to reduce this pain; however, its effects have not been assessed in combination with patellar resurfacing. The aim of this study is to evaluate the effect of PD on AKP and functional outcomes after TKA with patellar resurfacing.

METHODS

A prospective study was designed that included patients scheduled for TKA with patellar resurfacing. The 202 recruited patients were randomized into either the PD group or the non-denervation group [mean age 72.7 years (SD 8.2); 119 (70.4%) women and 50 (29.6%) men; average body mass index 31.4 kg/m² (SD 4.9)]. Pressure pain threshold (PPT) assessed by pressure algometry (PA), visual analogue scale(VAS), patellofemoral Feller score and the Knee Society Scores (KSS) were recorded preoperatively and at the 1-year follow-up.

RESULTS

169 patients were included in data analysis. At the 1-year follow-up, there were mild differences between denervation and non-denervation group in PPT value (494.4 kPa vs. 552.3 kPa, p = 0.047) and in VAS at stairs (2.9 vs. 1.5, p = 0.003) in favour of the non-denervation group. There was no difference in the improvement between groups in patellofemoral Feller score and KSS, but slightly higher improvement in non-denervation group in PPT (94.1 kPa vs. 160 kPa, p = 0.047), VAS walking (5.3 vs. 6.2, p = 0.041) and VAS at stairs (4.6 vs. 5.7, p = 0.022).

CONCLUSION

Patellar denervation does not improve AKP and clinical outcomes in primary TKA with patellar resurfacing compared to patellar replacement without denervation. PD cannot be recommended when patellar replacement is performed in TKA.

LEVEL OF EVIDENCE

II.

Influence of patellar denervation on anterior knee pain and knee function following total knee replacement: A systematic review and meta-analysis

BACKGROUND

Previous studies have reached mixed results regarding the effects of patellar denervation with electrocautery (PD) on total knee replacement (TKR). This systematic review and meta-analysis aimed to summarize all available literatures to investigate the influence of PD on postoperative anterior knee pain (AKP) and knee function after TKR.

METHODS

Electronic databases, including PubMed, Cochrane Library and Embase, were searched from their inception to March 2021. Randomized controlled trials (RCT) and quasi-randomized controlled trials (quasi-RCT) comparing PD and non-patellar denervation (NPD) in TKR were selected, and the Cochrane risk of bias tool was used to assess the quality of included trials. AKP prevalence was defined as the primary outcome.

RESULTS

A total of 12 RCTs and one quasi-RCT enrolled 1895 knees proved eligible. PD knees had significantly lower AKP prevalence than NPD knees (odds ratio [OR] = 0.54; 95% confidence intervals [95% CI], 0.36-0.81; p = 0.003). There was no difference between PD and NPD in terms of visual analogue scale for knee pain and range of motion, American knee society knee score, American knee society function score, patellar feller score, Oxford knee score for knee function. The results of subgroup analysis based on follow-up duration and patella resurfacing were in accordance with the results. PD knees were not associated with a higher risk of complication or revision.

CONCLUSION

PD can significantly reduce the AKP prevalence following TKR without increasing the risk of complication and revision. Although the pain relief effect of PD may not be associated with improved knee function after TKR, this procedure is preferred in both patella resurfacing and patella non-resurfacing TKR.

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

BACKGROUND

The 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.

METHODS

A 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.

RESULTS

The 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.

CONCLUSION

Given 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.

Patellar Denervation with Electrocautery Reduces Anterior Knee Pain within 1 Year after Total Knee Arthroplasty: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The effect of patellar denervation with electrocautery (PD) on anterior knee pain (AKP) after total knee arthroplasty (TKA) is still debated. The aim of this meta-analysis was to evaluate the current evidence regarding the use of PD in TKA without patellar resurfacing.

METHODS

A computerized search of published studies was performed in the PubMed, Embase and Cochrane Library databases in December 2019. Eligible studies were randomized controlled trials (RCTs) comparing clinical outcomes of the PD group and the non-PD group. Subgroup analyses were carried out according to the follow-up time (3, 12 months, and over 12 months) to evaluate whether the clinical effect of PD changed with time.

RESULTS

Ten RCTs were included in this meta-analysis. Pooled results showed a lower rate of AKP (Risk Ratio [RR] = 0.70; 95% confidence interval [CI], 0.50 to 0.97; P = 0.03) and a reduction in visual analogue scale (VAS) for AKP (mean difference, -0.37; 95% CI, -0.69 to -0.05; P = 0.02) in the PD group when compared to the non-PD group. Subgroup analyses found the differences in AKP incidence and VAS for AKP were significant at 3- and 12-month follow-up but not after 12-month follow-up. No significant difference was observed in functional scores between the two groups. No specific complication directly or indirectly related to PD was found.

CONCLUSION

PD can decrease the incidence and severity of AKP within 12 months after TKA, but the effect cannot be maintained after 12-month follow-up. Without significant associated complication and reoperation, the use of PD is still recommended in TKA without patellar resurfacing.

Effect of Patellar Denervation on Anterior Knee Pain and Knee Function in Total Knee Arthroplasty without Patellar Resurfacing: A Meta-Analysis of Randomized Controlled Trials

OBJECTIVE

The aim of the present study was to evaluate the effect of patellar denervation (PD) in preventing anterior knee pain (AKP) and improving knee function after total knee arthroplasty (TKA) without patellar resurfacing, and to help surgeons decide whether or not to use PD in TKA.

METHODS

The electronic databases of Pubmed, Embase, Cochrane, Web of Science, and Scopus were searched for all randomized controlled trials (RCT) comparing the outcomes of PD and no patellar denervation (NPD) in TKA without patellar resurfacing. Primary outcomes were incidence of AKP, visual analogue scale for pain (VAS), and patellar score (PS). Secondary outcomes were Knee Society Score (KSS), the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), the Oxford Knee Score (OKS), knee range of motion (ROM), and complications.

RESULTS

A total of nine RCT met the inclusion criteria. On meta-analysis, PD significantly reduced the incidence of AKP (odds ratio 0.49; 95% confidence interval [CI] 0.26 to 0.92), reduced the VAS (weighted mean difference [WMD] -0.57; 95% CI -1.02 to -0.11), and improved the WOMAC (WMD -4.63; 95% CI -6.49 to -2.77) and the ROM (WMD 9.60; 95% CI 0.39 to 18.81) during the follow-up within 12 months. In addition, PD improved the PS (WMD 1.01; 95% CI 0.65 to 1.38), KSS (WMD 1.12; 95% CI 0.10 to 2.14), and the WOMAC (WMD -1.41; 95% CI -2.74 to -0.08) during the follow-up after 12 months.

CONCLUSION

Patellar denervation could significantly reduce the VAS and the incidence of AKP in the early stages after TKA as well as improve the clinical outcomes in terms of the PS, the WOMAC, the KSS, and the ROM. This study demonstrates that PD is a safe and recommendable technique that could be routinely performed in TKA.

The efficacy of patellar denervation with electrocautery after total knee replacement: A meta-analysis of randomized controlled trials

OBJECTIVE

To evaluate the efficacy and safety of patellar denervation with electrocautery for reducing pain and improving clinical outcomes after total knee replacement.

METHODS

A comprehensive search was conducted across relevant databases, including PubMed, Scopus, EMBASE, Web of Science, and Cochrane Library databases on February 2020. Two researchers independently completed the literature screening, data extraction, and risk evaluation of bias. Outcome measures included visual analogue scale, opioid consumption, range of motion, patellar score, American Knee Society score, Oxford knee score and postoperative complications. STATA 13.0 software was applied for meta-analysis.

RESULT

A total of nine studies involving 1319 patients were included in our study. The present meta-analysis indicated that patellar denervation with electrocautery was associated with improved pain relief and decreased opioid consumption after total knee replacement. There was significant difference between groups in terms of knee range of motion.

CONCLUSION

Patellar denervation with electrocautery is effective in reducing pain and opioid consumption after total knee replacement. Postoperative range of motion is significantly better in patellar denervation group, which means that patellar denervation significantly improves clinical outcome.

A sleep disturbance after total knee arthroplasty

Background:

Knee osteoarthritis (OA) is common arthritis in elderly. Total knee arthroplasty; (TKA) is effective to restore mobility and improve quality of life in patients with OA. One of TKA complications is sleep disturbance.

Objective:

Aim was to evaluate sleep disturbance after TKA despite differences in postoperative pain managements.

Methods:

Prospective cohort study was performed on 67 patients who underwent primary TKA by different surgeons during May to March 2019. Samples were collected randomly from different hospitals in Sulaimani, Kurdistan, Iraq. Sleep pattern was assessed by Pittsburgh Sleep Quality Index (PSQI) and pain was assessed by visual analogue scale (VAS) for three months postoperatively.

Results:

Mean ± standard deviation (SD) age (year) and body mass index (BMI; kg/m²) of participants were 64.2 ± 7.5 (range: 40–82) and 27.3 ± 3.7 (range: 21.3–41.6), respectively. About 83.6% were females with male to female ratio of (0.2:1). There were statistically insignificant associations of age, gender, BMI, and history of diabetes mellitus with PSQI. Degree of pain was gradually decreasing during follow-up, but sleep was better at beginning followed by peaked disturbance after one month, then it started to improve gradually at end of follow-up.

Conclusions:

Sleep disturbance assessment needs multimodal approaches in order to improve it and satisfy patients.

Excellent 10-year patient-reported outcomes and survival in a single-radius, cruciate-retaining total knee arthroplasty

PURPOSE

Over 2 million Triathlon single-radius total knee arthroplasties (TKAs) have been implanted worldwide. This study reports the 10-year survival and patient-reported outcome of the Triathlon TKA in a single independent centre.

METHODS

From 2006 to 2007, 462 consecutive cruciate-retaining Triathlon TKAs were implanted in 426 patients (median age 69 (21-89), 289 (62.5%) female). Patellae were not routinely resurfaced. Patient-reported outcome measures (SF-12, Oxford Knee Scores (OKS), satisfaction) were assessed preoperatively and at 1, 5 and 10 years when radiographs were reviewed. Forgotten Joint Scores (FJS) were collected at 10 years. Kaplan-Meier survival analysis was performed.

RESULTS

At 10-11.6 years, 123 patients (128 TKAs) had died and 8 TKAs were lost to follow-up. There were four aseptic failures (two cases of tibial loosening, two cases of instability) and four septic failures requiring revision. Symptomatic aseptic radiographic loosening was present in three further cases at 11 years. Four (1%) patellae were secondarily resurfaced. OKS score improved by 17.7 ± 9.7 points at 1 year (p < 0.001), and was maintained at 34.7 ± 9.6 at 10 years with FJS 48.5 ± 31.4. Patient satisfaction was 88% at each timepoint. Ten-year survival was 97.9% (95% confidence interval 96.5-99.3) for revision for any reason, 98.9% (97.7-100) for mechanical failure, and 98.6% (97.4-99.8) for aseptic loosening (symptomatic radiographic or revised).

CONCLUSION

The Triathlon TKA continues to show excellent longer-term results with high implant survivorship, low rates of aseptic failure, consistently maintained PROMs and excellent patient satisfaction rates of 88% at 10 years.

LEVEL OF EVIDENCE

II, Prospective cohort study.

[Influence of lateral retinacular release on anterior knee pain following total knee arthroplasty]

Objective

To investigate the effect of lateral retinacular release on the clinical outcomes after total knee arthroplasty (TKA) without resurfacing of the patella.

Methods

A prospective randomized controlled study was performed on 132 patients with unilateral degenerative knee arthritis undergoing TKA bewteen October 2012 and October 2014, who met the selection criteria. During TKA, lateral retinacular release was used in 66 cases (trial group) and was not used in 66 cases (control group). Two patients were excluded from the study due to missing the follow-up in trial group. Four patients were excluded from the study due to lateral retinacular release in control group. Finally, 64 patients and 62 patients were included in the trial group and in the control group. There was no significant difference in gender, age, body mass index, side, disease duration, preoperative patellar morphology, grading of patellofemoral arthritis, grade of patellar cartilage degeneration, patellar malposition, patellar maltracking, patellar score, and Knee Society Score (KSS) between 2 groups ( P>0.05). The operation time, postoperative drainage volume, hospitalization time, postoperative complications, and patient satisfaction were recorded. Postoperative anterior knee pain was assessed by visual analogue scale (VAS), and the knee joint function was evaluated by KSS score and patellar score. The femoral angle, tibial angle, femoral flexion angle, and tibial posterior slope angle were measured on the X-ray film for postoperative prosthetic alignment. The postoperative patellar tracking and patellar position, as well as the presence of osteolysis, prosthesis loosening, patellar fracture and patellar necrosis were observed.

Results

All patients were followed up for 24 months. There was no significant difference in operation time, postoperative drainage volume, hospitalization time, and patient satisfaction between 2 groups ( P>0.05). The incidence of anterior knee pain in the trial group was better than that in the control group ( P=0.033). KSS score and patellar score were significantly improved in both groups at 24 months after operation when compared with preoperative scores ( P<0.05), but no significant difference was found between 2 groups ( P>0.05). Complications included hematoma (2 cases in the trial group, and 1 case in the control group), mild wound dehiscence (2 cases in each group respectively), skin-edge necrosis (1 case in the trial group), and superficial wound infection (1 case in each group respectively), which were cured by conservative treatment. No patellar necrosis, patella fracture, or knee lateral pain occurred in 2 groups. There was no significant difference in complication rate between groups ( P=0.392). Satisfactory implant alignment was observed in both groups during follow-up. There was no significant difference in femoral angle, tibial angle, femoral flexion angle, and tibial posterior slope angle between 2 groups ( P>0.05). No radiolucent line at the bone-implant interface was seen around the tibial components and femoral components in both groups. The patellar maltracking was observed in 3 patients of the trial group and 5 patients of the control group, showing no significant difference ( P=0.488). However, the incidence of patellar malposition in the trial group (18.8%) was significantly lower than that in the control group (35.5%) ( χ²=0.173, P=0.034).

Conclusion

Lateral retinacular release during primary TKA without resurfacing of the patella can reduce postoperative knee pain without increasing complications.

Different Factors Conduct Anterior Knee Pain Following Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

A systematic review and meta-analysis was performed to investigate the risks associated with anterior knee pain (AKP) following primary total knee arthroplasty (TKA).

METHODS

A computerized search was performed of the following databases: MEDLINE, Embase, and Cochrane Central (published prior to July 2017). A total of 37 studies, which included 1641 cases of AKP and 168,090 TKAs, were included in the meta-analysis.

RESULTS

A subgroup analysis revealed that compared with those without the following medical conditions, patients who had an infrapatellar fat pad excision and more than 12 months of follow-up (odds ratio [OR] 12.58, 95% confidence interval [CI] 3.245-48.781) were more likely to have AKP after TKA. Circumpatellar electrocautery (>12 months: OR 0.50, 95% CI 0.326-0.760; ≤12 months: OR 0.59, 95% CI 0.408-0.867) and patellar resurfacing (OR 0.25, 95% CI 0.131-0.485) may decrease the risk of AKP. Other factors, including the prosthesis bearing type (mobile bearing or fixed bearing) and the approach (midvastus compared with the medial parapatellar approach), were not significant risk factors for AKP.

CONCLUSION

The use of strategies such as patellar denervation and patellar resurfacing in primary TKA is recommended because they are safe and result in good clinical outcomes in preventing AKP. Caution should be taken when using an infrapatellar fat pad excision, because there is an increased risk of AKP at long-term follow-up (>12 months). Future studies should investigate these different strategies to confirm the underlying mechanisms and help prevent the occurrence of AKP after TKA. The timing of AKP onset remains unclear and requires further research.

Effect of Patellar Electrocautery Neurectomy on Postoperative Pain among Patients Referred for Total Knee Arthroplasty

Background

Anterior knee pain is a major problem in total knee arthroplasty (TKA). It is accepted that anterior knee pain (AKP) often contributes to a patellofemoral etiology; however, its etiology or treatment is not understood completely. Disabling pain receptors by electrocautery could theoretically lead to anterior knee area denervation. The present study aimed to evaluate the pain post-patellar denervation (PD) with electrocautery in TKA.

Materials and Methods

Clinical results for 92 patients who underwent TKA (58 women, 34 men; mean age 67.5 years) were analyzed. In addition to removal of all osteophytes, PD by electrocautery was performed on patella of treatment group (n = 46) and debridement alone including removing of all osteophytes was performed on the control group (n = 46). Knee Society System (KSS) score, patella score (PS), and visual analog scale (VAS) were used to determine pre- and post-operative AKP.

Results

The follow-up duration was 10 months. No revision or reoperations were performed. There were no patellar fractures. On all parameters (KSS score, PS, and VAS), there was a statistically significant pre- to post-operative difference in favor of the denervation group only 3 weeks after operation; however, there was no statistically difference postoperation on other follow-ups (3, 6, and 10 months).

Conclusions

PD with electrocautery could reduce AKP in TKA without patellar resurfacing only in a short-term period postoperation.

Comparison of patellofemoral outcomes after TKA using two prostheses with different patellofemoral design features

PURPOSE

The purpose of the present study was to compare the clinical and radiographic results after TKA using two prostheses with different sagittal patellofemoral design features, including outcomes related to compatibility of the patellofemoral joint.

METHODS

The clinical and radiographic results of 81 patients (100 knees) who underwent TKA using the specific prosthesis (group A) were compared with those in a control group who underwent TKA using the other prosthesis (group B). The presence of anterior knee joint pain, patellar crepitation, and patellar clunk syndrome was also checked.

RESULTS

The function score and maximum flexion angle at the last follow-up were slightly better in group A than those in group B (92.0 ± 2.3 vs. 90.6 ± 4.2) (133.6° ± 8.4° vs. 129.6° ± 11.4°). Anterior knee pain was observed in 6 knees and patellar crepitation in four knees in group A. In group B, these symptoms were observed in 22 knees and 18 knees, respectively. There was no patellar clunk syndrome in either group. The alignment was corrected with satisfactory positioning of components. The patellar height remained unchanged after TKA in the two groups. The differences between preoperative and postoperative patellar tilt angle and patellar translation were small.

CONCLUSION

When comparing the clinical and radiographic results after TKA using two prostheses with different sagittal patellofemoral design features, TKA using the specific prosthesis provided satisfactory results with less clinical symptoms related to the patellofemoral kinematics with TKA using the other prosthesis.

LEVEL OF EVIDENCE

III.

Role of Patellofemoral Offset in Total Knee Arthroplasty: A Randomized Trial

Total knee arthroplasty occasionally does not meet expectations. This randomized clinical trial assessed the effect of restoration of the native patellofemoral height on clinical outcomes. Group I underwent standard patellar bone resection; group II underwent modified patellar bone resection that adjusted the amount of anterior condylar bone removed and the anterior flange thickness. There were no differences in anterior knee pain, Western Ontario and McMaster Universities Arthritis Index scores, or Knee Injury and Osteoarthritis Outcome Score scores. Patellofemoral compartment height restoration versus patellar height alone does not appear to significantly reduce pain or improve function.

Patellar Resurfacing Versus Circumferential Denervation of the Patella in Total Knee Arthroplasty

This study compared the rates of anterior knee pain and functional outcomes between resurfaced patellas and non-resurfaced patellas with a circumpatellar denervation. One hundred ten patients who underwent patellar resurfacing or a circumpatellar denervation were evaluated for knee pain and functional outcomes at a minimum of 2 years after total knee arthroplasty. There were no significant differences between the 2 groups regarding Knee Society Scores, anterior knee pain scores, or visual analog scale scores. The groups had similar incidences of anterior knee pain. Most patients reported no to mild effect of anterior knee pain on daily living. Patients in each group reported increased pain with kneeling, squatting, and departing an automobile. Similar proportions of patients were disappointed with their overall outcomes in each group. Circumpatellar denervation and patellar resurfacing during total knee arthroplasty lead to similar incidences of anterior knee pain. [Orthopedics. 2016; 39(5):e1019-e1023.].

Is patellar denervation necessary in total knee arthroplasty without patellar resurfacing?

PURPOSE

To conduct a meta-analysis with randomized controlled trials (RCTs) published in full text to determine the effectiveness of patellar denervation (PD) in primary total knee arthroplasty (TKA).

METHODS

Literature search was performed in PubMed, Embase, Web of Science and Cochrane Library for information from the earliest date of data collection to February 2015. RCTs comparing the benefits and risks of PD with those of no patellar denervation (NPD) in primary TKAs were included. Statistical heterogeneity was quantitatively evaluated by X(2) test with the significance set P < 0.10 or I (2) > 50 %.

RESULTS

Six RCTs consisting of 751 patients were included. The incidences of AKP in PD group and NPD group were 38.3 % (90/235) and 46.3 % (107/231), respectively. Meta-analysis showed significant prevention effect of PD on the incidence of AKP (OR 0.65; 95 % CI 0.42, 1.00; P = 0.05) without significant heterogeneity (I (2) = 44 %, P = 0.15). Our results also indicated that PD was significantly associated with better American Knee Society knee (WMD = 2.50; 95 % CI 0.34, 4.67; P = 0.02) and functional scores (WMD = 4.07; 95 % CI 1.34, 6.80; P = 0.0003) and range of motion (ROM) (WMD = 4.27; 95 % CI 1.95, 6.60; P = 0.0003) compared with NPD. However, there was no significant difference between the two groups no matter in Oxford knee score, patellar score or visual analogue scale at any other time. Complications and revisions did not differ significantly between the two groups.

CONCLUSION

This meta-analysis showed that PD in TKAs without patellar resurfacing, compared with NPD, could prevent the incidence of post-operative AKP and improve clinical outcome in KSS and post-operative ROM. Based on the above results, PD was a safe procedure with no significant complications and revision or re-operations.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

Does patellar denervation reduce post-operative anterior knee pain after total knee arthroplasty?

PURPOSE

The effectiveness of patellar denervation in reducing anterior knee pain and improving patient satisfaction and quality of life after total knee arthroplasty (TKA) is still controversial. A meta-analysis was conducted to try to settle the controversy.

METHODS

The electronic databases PubMed, Web of Science, Embase, and Cochrane Library were systematically searched. Of 374 papers identified, seven randomised controlled trials involving 898 patients (983 knees) were eligible for data extraction and meta-analysis.

RESULTS

Analysis showed that patellar denervation can significantly improve clinical outcomes for the first 12 months of follow-up after TKA, including anterior knee pain incidence (P = 0.008), visual analogue scale score (P < 0.001), patellar score (P < 0.001), Knee Society Score (P = 0.03), Knee Society Score function score (P = 0.03), and knee range of motion (P = 0.008). However, no statistical significance in outcomes was found between the patellar denervation group and no-denervation group for any of those parameters after 12 months of follow-up.

CONCLUSION

The best currently available evidence suggests that patellar denervation can significantly reduce anterior knee pain incidence and improve early clinical outcomes after TKA. However, after a prolonged period of follow-up, this advantage seems to disappear. Even so, the use of patellar denervation in primary TKA is recommended because it is safe and produces good early clinical outcomes.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

Five-year survivorship and patient-reported outcome of the Triathlon single-radius total knee arthroplasty

PURPOSE

The Triathlon single-radius total knee arthroplasty (TKA) was used in 11% of primary procedures in England and Wales in 2011 making it the third most common prosthesis implanted. To date, there has been no independent report of survivorship or outcome for this implant. The aim of this study was to report the 5-year survival and patient-reported outcome of the Triathlon TKA in a single independent centre.

METHODS

Four hundred and sixty-two consecutive Triathlon TKAs were implanted at the study centre from 2006 to 2007. The mean age was 68.7 (21-89) years, and 290 patients were women (62.7%). The Short Form 12 and Oxford Knee Score (OKS) were obtained pre-operatively and at 1 and 5 years post-operatively when satisfaction was also assessed and radiographs reviewed.

RESULTS

Forty-one had died and nine were lost to follow-up. There were three aseptic failures: two cases of tibial aseptic loosening and one of secondary instability. There were five additional septic failures. OKS improved by a mean of 17.4 points at 1 year from 41.3 pre-operatively (p < 0.001). This was unchanged at 5 years (n.s.). Patient satisfaction was high with 88% being satisfied or very satisfied at 1 and 5 years. Kaplan-Meier analysis demonstrated a 5-year survival of 97.6% (95% CI 95.6-99.6) for failure for any reason, and 99.5% (95% CI 98.7-100) for aseptic loosening.

CONCLUSION

The Triathlon TKA offers good mid-term survivorship and functional outcome, which is reflected by a high patient satisfaction rate.

LEVEL OF EVIDENCE

Therapeutic, Level IV.

Patellofemoral resurfacing and patellar denervation in primary total knee arthroplasty

PURPOSE

To conduct a systematic review and network meta-analysis of randomized controlled trials (RCTs) with the aim of comparing relevant clinical outcomes between patellar denervation, resurfacing and non-resurfacing.

METHODS

A database search was performed using PubMed and Scopus search engines. RCTs or quasi-experimental designs comparing clinical outcomes between treatments by a search of articles dated from inception to October 23, 2012. Unstandardized mean difference (UMD) and random effects methods were applied for pooling continuous and dichotomous outcomes, respectively. A longitudinal mixed regression model was used for network meta-analysis to indirectly compare treatment effects.

RESULTS

Eighteen of 315 studies identified were eligible. Compared with patellar non-resurfacing, patellar denervation had a UMD that displayed a significant improvement in symptoms with values in pain visual analog score (VAS) and Knee Society Score (KSS) of -0.6 [95% confidence interval (CI) -1.13, -0.25] and 2.55 (95% CI 0.43, 4.68), respectively. The UMD in VAS, KSS, and Knee Function Score (KFS) in patellar resurfacing showed no significant improvement in symptoms when compared to non-resurfacing. Patients who underwent surgery with patellar resurfacing had a lower reoperation rates with pooled relative risks (RRs) of 0.69 (95% CI 0.50, 0.94) when compared to non-resurfacing. The network meta-analysis suggested a benefit of borderline significance for patellar denervation with a pooled RR of 0.63 (95% CI 0.38, 1.03), showing that there is a lower chance of anterior knee pain when compared to non-resurfacing. Patellar resurfacing also displays a significantly lower chance of reoperation with a pooled RR of 0.68 (95% CI 0.50, 0.92) when compared to non-resurfacing. Multiple active treatment comparisons indicated that patellar denervation resulted in greater improvement in KFS than patellar resurfacing.

CONCLUSION

This review suggests that either patellar denervation or patellar resurfacing may be selected for the management of the patellofemoral component in total knee replacement. Patellar denervation may help improve postoperative knee function, but does not improve pain when compared to patellar resurfacing.

Circumferential electrocautery of the patella in primary total knee replacement without patellar replacement: a meta-analysis and systematic review

The purpose of this meta-analysis and systematic review was to identify and assess whether circumferential electrocautery is useful for improving outcomes after primary total knee replacement(TKR). We searched MEDLINE, EMBASE, PubMed, SpringerLink, Web of Knowledge, OVID CINAHL, OVID EBM and Google Scholar and included articles published through January 2014. A total of 6 articles met the inclusion criteria. Of the 776 cases included in the analysis, 388 cases involved patellar denervation, and 388 cases were designated as the control group. The meta-analysis revealed no significant difference in the incidence of anterior knee pain (AKP, p = 0.18) or in the visual analogue scale score (VAS, p = 0.23) between the two groups. In addition, AKSS Function Score indicated no significant difference between the two groups (p = 0.28). However, the OKS (p = 0.02), patellar score (p = 0.01), AKSS-Knee Score (p = 0.004), range of motion (ROM, p < 0.0001) and WOMAC Score (p = 0.0003) indicated that circumpatellarelectrocautery improved clinical outcomes compared with non-electrocautery. The results indicate that circumferential electrocautery of the patella does not significantly improve AKP compared with non-electrocautery techniques but that circumferential electrocautery significantly improves patients' knee function after surgery. Therefore, we believe that circumferential electrocautery is beneficial to the outcome of primary TKR surgery without patellar replacement.

Patellar denervation in total knee arthroplasty without patellar resurfacing and postoperative anterior knee pain: a meta-analysis of randomized controlled trials

The aim of this meta-analysis was to investigate whether patellar denervation with electrocautery (PD) after total knee arthroplasty (TKA) could reduce the postoperative anterior knee pain (AKP). Five randomized controlled trials (RCTs) with 572 patients and 657 knees were eligible for this meta-analysis. Our results showed that PD was associated with less AKP, lower visual analogue scale (VAS), higher patellar scores and better knee function compared with no patellar denervation (NPD). Complications did not differ significantly between the two groups. The existing evidence indicates that PD may be a better approach, as it improves both anterior knee pain and knee function after TKA. Future multi-center randomized controlled studies with large sample sizes are required to verify the current findings.

Patellar denervation with electrocautery in total knee arthroplasty without patellar resurfacing: a meta-analysis

PURPOSE

The impact of patellar denervation with electrocautery in total knee arthroplasty (TKA) on post-operative outcomes has been under debate. This study aims to conduct a meta-analysis and systematic review to compare the benefits and risks of circumpatellar electrocautery with those of non-electrocautery in primary TKAs.

METHODS

Comparative and randomized clinical studies were identified by conducting an electronic search of articles dated up to September 2012 in PubMed, EMBASE, Scopus, and the Cochrane databases. Six studies that focus on a total of 849 knees were analysed. A random-effects model was conducted using the inverse-variance method for continuous variables and the Mantel-Haenszel method for dichotomous variables.

RESULTS

There was no significant difference in the incidence of anterior knee pain between the electrocautery and non-electrocautery groups. In term of patellar score and Knee Society Score, circumpatellar electrocautery improved clinical outcomes compared with non-electrocautery in TKAs. The statistical differences were in favour of the electrocautery group but have minimal clinical significance. In addition, the overall complications indicate no statistical significance between the two groups.

CONCLUSIONS

This study shows no strong evidence either for or against electrocautery compared with non-electrocautery in TKAs.

LEVEL OF EVIDENCE

Therapeutic study (systematic review and meta-analysis), Level III.

A randomised, controlled trial of circumpatellar electrocautery in total knee replacement without patellar resurfacing: a concise follow-up at a mean of 3.7 years

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years' follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years' follow-up.

Less anterior knee pain with a routine lateral release in total knee arthroplasty without patellar resurfacing: a prospective, randomized study

PURPOSE

Anterior knee pain is a major cause of complaint in total knee arthroplasty (TKA) without patellar resurfacing. The concept of improved patellar tracking and decreased retropatellar contact pressure for lateral retinacular release theoretically suggests that patients with lateral retinacular release in TKA would achieve a lower incidence of anterior knee pain when compared without lateral retinacular release. We sought to determine (1) whether those patients who received a routine lateral retinacular release in TKA would attain lower incidence of anterior knee pain as compared to patients who received TKA without lateral retinacular release and (2) whether lateral retinacular release would increase the lateral retinacular release-related complications.

METHODS

A total of 148 patients who underwent TKA with the use of the Gemini MK II mobile bearing were randomized to receive either routine lateral retinacular release (intervention group) or not (control group). Patients were assessed by the visual analogue scale for anterior knee pain, the Knee Society clinical scoring system of knee score and function score, and patellar score for clinical function. Patients' satisfaction and lateral retinacular release-related complications were also evaluated.

RESULTS

The overall incidence of anterior knee pain in the intervention group at 18 months follow-up was 5.6%, while that of the control group was 20.6% (p = 0.009). No statistical difference was detected between the two groups in terms of lateral retinacular release-related complications (n.s.), patients' satisfaction (n.s.), knee score (n.s.), function score (n.s.), and patellar score (n.s.) at 18 months follow-up.

CONCLUSION

The present study suggests that routine lateral retinacular release can reduce anterior knee pain and does not increase lateral retinacular release-related complications, in TKA with the use of the Gemini MK II mobile bearing without patellar resurfacing.

LEVEL OF EVIDENCE

Therapeutic, Level I.

Does patellar rim electrocautery have deleterious effects on patellar cartilage?

BACKGROUND

Circumpatellar electrocauterization to destroy pain receptors during total knee arthroplasty without patellar resurfacing is commonly used to decrease postoperative knee pain. We aimed to evaluate the effect of denervation with electrocauterization on patellar cartilage.

METHODS

Twenty rabbits were randomly assigned to two equally sized case and control groups. The rabbits in the case group underwent surgery via the anterior midline skin incision and medial parapatellar arthrotomy, followed by denervation electrocauterization at a depth of 1 mm and a distance of 3 mm from the outer border of the patella. In the control group, surgery was identical to that performed in the case group, but without patellar denervation. Twelve weeks after surgery, all rabbits were sacrificed. Range of motion, macroscopic evaluation of cartilage using modified Outerbridge scoring, and histopathological assessment using a modified histologic scoring system for cartilage were evaluated.

RESULTS

Three rabbits died during the study. Nine cases and eight animals from the control group were included in the final evaluation. All rabbits had passive full range of motion. Mean Outerbridge score was 2.0 in the case group and 0.37 in the control group (p=0.002). There were statistically significant differences in cellularity (p=0.016), loss of matrix (p=0.004), and clustering of chondrocytes (p=0.008) between the two groups. Microscopic variables as a whole were statistically significant (p=0.001).

CONCLUSIONS

Circumpatellar electrocauterization may result in cartilage destruction. So, we encourage caution in using routine electrocauterization in patients undergoing total knee arthroplasty.

LEVEL OF EVIDENCE

level II.