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Purpose Anterior knee pain can significantly affect the quality of life of those living with it. One approach to addressing anterior knee pain involves the selective denervation of the patella to reduce afferent pain transmission, but there has been no consensus on the number, location, or origin of the nerves innervating the patella. In this study, we review existing literature on anterior knee innervation and present findings from our cadaveric dissection to provide a detailed description of the innervation of the anterior knee joint. Materials and methods Two independent authors reviewed the literature on anterior knee innervation from PubMed and Embase, and a sub-search was conducted on the relationship between the infrapatellar branch of the saphenous nerve (IPBSN) and the anterior knee compartment. Subsequently, two fresh-frozen cadavers were dissected to determine whether the saphenous nerve innervates the anterior knee compartment and to confirm, through tissue biopsies stained with laminin and beta-III-tubulin, whether previously described nerves innervate the patella. Results A total of 463 and 304 entries on patellar innervation and saphenous nerve anatomy, respectively, were identified through PubMed and Embase. Descriptions of the nerves innervating the patella were found to be inconsistent and are summarized. No studies identified branches of the IPBSN directly innervating the patella or patellar tendon. On cadaveric dissection, we found that anterior knee innervation comprised the nerves within the distal vastus medialis and lateralis muscles, the medial and lateral retinacular nerves, and occasionally a branch of the IPBSN that innervated the inferomedial anterior knee skin. Conclusions This study is the first to provide histological confirmation of patellar innervation by the IPBSN. Our findings suggest that an approach based on a positive response to differential nerve blocks, followed by resection of the nerves implicated in that anterior compartment knee pain, may be more effective in treating persistent anterior knee pain than circumferential electroablation of the patella or routine resection of the IPBSN. Level of evidence Level III.

Objective This randomized controlled trial conducted a comparative analysis of postoperative outcomes between a modified anteromedial incision with saphenous nerve protection and the traditional medial parapatellar approach in total knee arthroplasty (TKA). We aimed to test the hypothesis that the nerve-sparing modified technique would significantly reduce postoperative anterior knee numbness and pain while maintaining surgical feasibility. Methods Sixty-eight TKA candidates (January 2022-June 2023) were prospectively randomized into two groups: Modified ( n  = 34) and Traditional ( n  = 34) approaches. The modified technique featured an anteromedial incision with infrapatellar branch visualization and preservation, whereas the control group received the traditional medial parapatellar exposure. Primary outcomes included numbness area and the Visual Analog Scale score; secondary outcomes encompassed surgical parameters (duration, blood loss) and functional recovery (Hospital for Special Surgery Knee score). Results Thirty one patients were randomized to the M group and 29 patients allocated to the T group. Compared to the T group, the M group demonstrated significantly lower VAS scores at 3 days, 7 days, and 2 weeks postoperatively, with statistical significance ( P  < 0.05). The M group showed a statistically significant reduction in the area of numbness compared to the T group at all postoperative follow-up intervals: 2 weeks, 1 month, 3 months, 6 months, and 1 year ( P  < 0.05 for all time points). However, postoperative HSS scores did not differ significantly between the M group and the T group at any follow-up interval ( P  > 0.05). Conclusion The nerve-preserving modified approach achieved superior patient-reported outcomes (PROs) in reducing anterior knee numbness and early postoperative pain without compromising prosthesis implantation accuracy or functional recovery trajectories, suggesting its potential as a standardized refinement in TKA surgical protocols. Trial registration Chinese Clinical Trial Registry, ChiCTR2500107220, 6 August 2025, retrospectively registered.

Objective The aim of this study was to investigate the effect of patellar denervation (PD) on pain, function and ability to kneel after unicompartmental knee arthroplasty (UKA). Methods Patients with medial knee osteoarthritis who underwent UKA were prospectively selected. Patients were randomly divided into PD and non-PD groups based on whether patellar denervation was performed. Clinical assessment was performed using the Hospital for Special Surgery (HSS) knee score, Kujiala score, visual analogue scale (VAS) and forgotten joint score (FJS-12), as well as postoperative complications were recorded. The patients’ postoperative self-perception and actual ability to perform different kneeling positions were assessed in the two groups. Results UKA patients treated with PD achieved better Kujiala scores and FJS-12 scores, reduced anterior knee pain and improved kneeling ability postoperatively, validating the effectiveness of PD in UKA. Perception and actual performance of kneeling remained mismatched in PD patients, but performance during different kneeling activities was generally better than in non-PD patients. Trial registration Clinical Trial Registration: ChiCTR1900025669. Conclusion Patellar denervation can safely and effectively improve patellofemoral joint function, pain and kneeling ability in the early postoperative period after UKA.

There is no information on the pattern of blood vessel innervation, and in principle no information on innervation in general, in the human patellar tendon. In the present study, biopsies from the proximal part of normal and pain‐free patellar tendons (11 men, mean age 33 years) were examined. The specimens were evaluated by using antibodies against the general nerve marker protein gene‐product 9.5 (PGP 9.5) and the sensory neuropeptides substance P (SP) and calcitonin gene‐related peptide (CGRP), and immunohistochemistry. It was observed that the arteries, and to some extent the small vessels, in the loose paratendinous connective tissue were supplied with PGP 9.5‐ as well as SP‐ and CGRP‐innervations. There was a marked PGP 9.5‐like immunoreaction (LI), and to some extent also SP‐ and CGRP‐LI, in the large nerve fascicles in this tissue. In the tendon tissue proper, PGP 9.5‐LI was detected in nerve fibers located in the vicinity of some of the blood vessels and in thin nerve fascicles. There was a low degree of SP‐ and CGRP‐innervation in the tendon tissue proper. The observations give a morphologic correlate for the occurrence of nerve‐mediated effects in the patellar tendon. Particularly it seems as if there is a marked nerve‐mediated regulation of the blood vessels supplying the tendon, at the level where they course in the loose paratendinous connective tissue.

Purpose The infrapatellar branch of the saphenous nerve (IPBSN) plays a critical role in cutaneous innervation of the anterior knee and is frequently implicated in both acute and chronic post-surgical pain. Due to its anatomical variability, precise localization is essential for effective nerve blocks and minimizing iatrogenic injury. This study evaluates the feasibility of two distal ultrasound-guided approaches for selective IPBSN blocks, with the aim of addressing the limitations of proximal techniques. Methods Anatomical layer-by-layer dissections of two paired lower limbs and transverse cross-sections of a third limb were used to map the IPBSN’s course and its relationship to the sartorius muscle. Based on these findings, two distal ultrasound-guided approaches were tested: a proximal medial para-patellar approach at the level of the patella’s superior aspect and a distal medial para-patellar approach near the medial femoral condyle. Ultrasound-guided injections (0.1–0.3 mL) targeting the IPBSN were performed on four lower limbs, followed by anatomical validation through dissection. Results The IPBSN was consistently identified as a honeycomb structure within a distinct fascial compartment. Both approaches effectively localized the nerve, with observed diffusion suggesting a potential compartment for selective nerve block. This dual-modality approach of ultrasound imaging and dissection enabled precise IPBSN localization, overcoming topographical variability relative to the sartorius muscle. Conclusion Distal ultrasound-guided IPBSN blocks show promise for knee pain management by achieving targeted analgesia while preserving muscle function. Further studies are needed to validate these techniques and refine injection protocols for clinical use.

Background This study aimed to evaluate the effectiveness of circumferential patellar denervation in reducing anterior knee pain (AKP) and improving clinical outcomes after total knee arthroplasty (TKA) without patellar resurfacing. Materials and methods This prospective, non-randomized, observational study included patients who underwent primary TKA at our institution between August 2023 and January 2024. Patients were divided into two groups: those who received patellar denervation (PD group) and those who did not (NPD group). The primary outcome was the reduction in anterior knee pain (AKP), measured by the Visual Analog Scale (VAS). Secondary outcomes included the Kujala Knee Score, Western Ontario and McMaster Universities Arthritis Index (WOMAC), and range of motion (ROM). Assessments were conducted preoperatively and at 3 and 6 months postoperatively. Results Four patients in the PD group and five in the NPD group were excluded from the study due to failure to complete follow-up. Thus, 74 female and 16 male patients with a mean age of 67.4 ± 4.2 years were included in the final analysis. There were no significant differences between the two groups with respect to age, sex, side of surgery, height, weight, BMI, grade of patellofemoral osteoarthritis, preoperative ROM, VAS score, Kujala score, and WOMAC score (p: n.s. for all variables). No significant differences were found between the groups for VAS, Kujala, and WOMAC scores at any time point (p: n.s.). Significant improvements in these scores over time were indicated by repeated measures ANOVA ( p  = 0.001 for both groups). Pairwise comparisons showed significant improvements from preoperative to postoperative months three and six and from postoperative months three to six ( p  = 0.001 for all comparisons). Both groups experienced decreased knee ROM at third month, which returned to preoperative values at sixth month with no significant differences. No complications were observed during the study. Conclusions Circumferential patellar denervation does not provide additional benefit in reducing anterior knee pain or improving functional outcomes compared to the non-denervation approach in TKA without patellar resurfacing. Level of evidence Level III, Prospective comparative study.

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. Patellar denervation significantly reduces anterior knee pain, after total knee arthroplasty. While functional outcomes improve statistically in the patellar denervation group, the differences are below the clinically important threshold. No significant distinctions in visual analogue scale and range of motion are observed between patellar denervation and non‐denervation groups.

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.

BackgroundInfrapatellar branch of saphenous nerve (IPBSN) is more prone for injuries during various surgical interventions of the knee. The aim of this study was to know the course and branching pattern of the IPBSN and describe its anatomical variations.Material and methodTo achieve these objectives, we dissected 32 male cadaveric knees. Origin of the nerve was traced in relation with the sartorius muscle; course and terminal branches of the nerve were noted.ResultsIn majority of the cases (68.7 %), the nerve was found to emerge near the anterior border of sartorius muscle, distance between the medial margin of the patella and the nerve trunk was ranging between 4 and 7 mm. In majority of the cases (65.6 %), division of the nerve trunk was located between the apex of patella and tibial tuberosity. In majority of the cases, single branch was observed (40.6 %).ConclusionBy enriching the knowledge of these variable anatomical position of the IPBSN, surgeon can try to minimize the risk of nerve damage by avoiding the high risk zones while performing medial knee incision, blind puncture or an arthrotomy thus avoiding the unwanted complications.

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.