Percutaneous pulsed radiofrequency ablation of articular nerves of the hip joint in patients with chronic hip pain refractory to conventional analgesics.

OBJECTIVES: Total Hip Arthroplasty (THA) may be a risky proposition in patients with comorbidities, and they may require systemic analgesics for chronic hip pain (CHP). Since traditional pain medications may not provide complete pain relief or carry prohibitive adverse effects, pulsed radiofrequency (PRF) treatment of the hip articular nerves (HAN) has been proposed for effective clinical outcomes. We determined the efficacy of PRF-HAN in improvement in CHP compared to baseline pain on conventional systemic analgesics. METHODS: Between August 2015 and December 2021, 31 adult patients with severe comorbid conditions and excruciating chronic hip pain were subjected to a PRF-HAN procedure following a diagnostic block. All 31 patients received PRF of the articular branches of the femoral and obturator nerves. Demographic parameters, numerical rating scale (NRS), Harris Hip Score (HHS), WOMAC scores, the change of these scores from baseline, and any adverse effects were recorded before treatment and on day 1, 1st week, 6 weeks, and 6 months after treatment. RESULTS: All the patients who underwent the PRF-HAN reported a significant improvement in NRS, HHS, and WOMAC scores compared to the baseline values on day 1, at the end of the 1st week, and the 6th week (p<0.001). No adverse events were documented in the study post-procedure until the end of 6 months. CONCLUSION: PRF-HAN is a strong alternative for chronic pain management and augments physical functioning and a return to daily activity in patients who would be deprived of arthroplasty considering associated comorbid conditions.

Intramuscular innervation of the tensor fasciae latae: Application to total hip arthroplasty.

The aims of this study were to clarify the extra- and intramuscular branching patterns of the tensor fasciae latae (TFL) with reference to surface landmarks on the thigh and to thus suggest a safe approach for total hip arthroplasty. Sixteen fixed and four fresh cadavers were dissected and subjected to the modified Sihler's staining method to reveal the extra- and intramuscular innervation patterns, and the findings were matched with surface landmarks. The landmarks were measured from the anterior superior iliac spine (ASIS) to the patella and divided into 20 parts along the total length. The average vertical length of the TFL was 15.92 ± 1.61 cm, which was 38.79 ± 2.73% when converted to a percentage. The entry point of the superior gluteal nerve (SGN) was an average of 6.87 ± 1.26 cm (16.71 ± 2.55%) from the ASIS. In all cases, the SGN entered parts 3-5 (10.1%-25%). As the intramuscular nerve branches traveled distally, they had a tendency to innervate more deeply and inferiorly. In all cases, the main SGN branches were intramuscularly distributed in parts 4 and 5 (15.1%-25%). Most tiny SGN branches were found inferiorly in parts 6 and 7 (25.1%-35%). In three of 10 cases, very tiny SGN branches were observed in part 8 (35.1%-38.79%). We did not observe SGN branches in parts 1-3 (0%-15%). When information on the extra- and intramuscular nerve distributions was combined, we found that the nerves were concentrated in parts 3-5 (10.1%-25%). We propose that damage to the SGN can be prevented if parts 3-5 (10.1%-25%) are avoided during surgical treatment, particularly during the approach and incision.

Sciatic nerve movement in the deep gluteal space during hip rotations maneuvers.

We hypothesize that the sciatic nerve in the subgluteal space has a specific behavior during internal and external coxofemoral rotation and during isometric contraction of the internal and external rotator muscles of the hip. In 58 healthy volunteers, sciatic nerve behavior was studied by ultrasound during passive internal and external hip rotation movements and during isometric contraction of internal and external rotators. Using MATLAB software, changes in nerve curvature at the beginning and end of each exercise were evaluated for longitudinal catches and axial movement for transverse catches. In the long axis, it was observed that during the passive internal rotation and during the isometric contraction of external rotators, the shape of the curve increased significantly while during the passive external rotation and the isometric contraction of the internal rotators the curvature flattened out. During passive movements in internal rotation, on the short axis, the nerve tended to move laterally and forward, while during external rotation the tendency of the nerve was to move toward a medial and backward position. During the isometric exercises, this displacement was less in the passive movements. Passive movements of hip rotation and isometric contraction of the muscles affect the sciatic nerve in the subgluteal space. Retrotrochanteric pain may be related to both the shear effect of the subgluteus muscles and the endoneural and mechanosensitive aggression to which the sciatic nerve is subjected.

A systematic review and meta-analysis of the hip capsule innervation and its clinical implications.

Detailed understanding of the innervation of the hip capsule (HC) helps inform surgeons' and anaesthetists' clinical practice. Post-interventional pain following radiofrequency nerve ablation (RFA) and dislocation following total hip arthroplasty (THA) remain poorly understood, highlighting the need for more knowledge on the topic. This systematic review and meta-analysis focuses on gross anatomical studies investigating HC innervation. The main outcomes were defined as the prevalence, course, density and distribution of the nerves innervating the HC and changes according to demographic variables. HC innervation is highly variable; its primary nerve supply seems to be from the nerve to quadratus femoris and obturator nerve. Many articular branches originated from muscular branches of the lumbosacral plexus. It remains unclear whether demographic or anthropometric variables may help predict potential differences in HC innervation. Consequently, primary targets for RFA should be the anterior inferomedial aspect of the HC. For THA performed on non-risk patients, the posterior approach with capsular repair appears to be most appropriate with the lowest risk of articular nerve damage. Care should also be taken to avoid damaging vessels and muscles of the hip joint. Further investigation is required to form a coherent map of HC innervation, utilizing combined gross and histological investigation.

Anatomic Relationship of the Femoral Neurovascular Bundle in Patients With Congenital Femoral Deficiency.

BACKGROUND: Congenital femoral deficiency (CFD) is a rare condition that affects the morphology of the hip and surrounding soft tissues. Bony deformity and distorted muscular anatomy are well known, but no studies have described the relationship of the femoral neurovascular (NV) bundle to surgically relevant anatomic landmarks. The authors compared the location of the femoral NV bundle on the affected side in patients with CFD with the unaffected side. The authors hypothesized that the bundle on the pathologic side would be in an abnormal position relative to the unaffected side. METHODS: Thirty-three patients diagnosed with unilateral CFD who had undergone preoperative magnetic resonance imaging of the pelvis were included in our study. The authors identified the femoral NV bundle on the axial cuts and measured its distance from the anterior superior iliac spine (ASIS), anterior inferior iliac spine (AIIS), and lesser trochanter (LT). Anatomic percent change and absolute measurements were then compared and correlated with associated boney deformities and the Paley classification. RESULTS: The distance from the femoral NV bundle to the ASIS, AIIS, and LT was significantly different compared with the unaffected side. The AIIS absolute distance and AIIS percent change significantly correlated with the neck-shaft angle of the proximal femur. CONCLUSIONS: In patients with CFD, the femoral NV bundle seems to be further from the LT and closer to the AIIS on the affected side when compared with the unaffected side. magnetic resonance imaging may be helpful to understand the course of the femoral NV bundle before reconstruction in patients with CFD; however, the authors recommend identification of the femoral NV bundle before transection of the proximal rectus femoris tendon to provide safe surgical care. LEVEL OF EVIDENCE: Level IV-case-control study of diagnostic studies.

Anatomical basis for the selective block of the nerve to quadratus femoris by way of percutaneous techniques / Bases anatómicas para el bloque selectivo del nervio del músculo cuadrado femoral a través de técnicas percutáneas

SUMMARY: Hip joint chronic pain can severely compromise patients' life quality. Peripheral nerve blocks play an important role as diagnostic and therapeutic procedures. The aim of this work is to study the anatomy of the nerve to quadratus femoris (NQF) in view of the possibility of its percutaneous selective block. Forty-three gluteal cadaveric regions fixed in formaldehyde solution were dissected. The quadratus femoris, the obturator internus and superior and inferior gemellus were freed from their lateral insertion, exposing thus the posterior aspect of the hip joint. The NQF was identified, and the horizontal distance to the posterior edge of the greater trochanter at its upper, middle and lower thirds was registered. The number of the articular branches of the NQF was identified. Likewise, the horizontal distance to the posterior edge of the greater trochanter and the longitudinal distance to the line through the distal end of the posterior edge of the greater trochanter were measured. The distance between the NQF and the greater trochanter posterior edge at upper, middle and lower thirds was 46 mm, 41 mm and 35 mm, respectively. In most cases (85 %) the NQF presented one or two articular branches. The longitudinal distances between the line through the distal end of the posterior edge of the greater trochanter and the origin of the first, second and third articular branches of the NQF were 14.7 mm (-19.4 - 40), 16.4 mm (-9.3-42) and 27 mm (0-46), respectively. The distances to the posterior edge of the greater trochanter were 43.1 mm (16.3-66), 37.7 mm (6.5-53) and 39.8 mm (26-52), for the first, second and third articular branches, respectively. In conclusion, the articular branches of the nerve to quadratus femoris have a constant and predictable distribution. Our findings allow for generating a coordinate system for the selective block of the NQF by way of percutaneous techniques.

RESUMEN: El dolor crónico de la articulación coxal puede comprometer severamente la calidad de vida de los pacientes. Los bloqueos nerviosos periféricos juegan un papel importante como procedimientos diagnósticos y terapéuticos. El objetivo de este trabajo es estudiar la anatomía del nervio del músculo cuadrado femoral (NCF) en vista de la posibilidad de su bloqueo selectivo percutáneo. Se utilizaron 22 cadáveres fijados en solución de formaldehído. Fueron disecadas en total 43 regiones glúteas. Los músculos cuadrado femoral, obturador interno y los gemelos superior e inferior fueron liberados de su inserción lateral, exponiendo así la cara posterior de la articulación coxal. Se identificó el NCF y se registró la distancia horizontal al margen posterior del trocánter mayor en sus tercios superior, medio e inferior. Se identificó el número de ramas articulares del NQF. Asimismo, se midió la distancia horizontal al margen posterior del trocánter mayor y la distancia longitudinal a la línea que pasa por el extremo distal del margen posterior del trocánter mayor. La distancia entre el NCF y el margen posterior del trocánter mayor en los tercios superior, medio e inferior fue de 46 mm, 41 mm y 35 mm, respectivamente. En la mayoría de los casos (85 %) el NCF presentó una o dos ramas articulares. Las distancias longitudinales entre la línea que pasa por el extremo distal del margen posterior del trocánter mayor y el origen de la primera, segunda y tercera ramas articulares del NQF fueron 14,7 mm (-19,4 - 40), 16,4 mm (-9,3-42) y 27 mm (0-46), respectivamente. Las distancias al margen posterior del trocánter mayor fueron 43,1 mm (16,3-66), 37,7 mm (6,5-53) y 39,8 mm (26-52), para la primera, segunda y tercera ramas articulares, respectivamente. En conclusión, las ramas articulares del nervio al cuadrado femoral tienen una distribución constante y predecible. Nuestros hallazgos permiten generar un sistema de coordenadas para el bloqueo selectivo del NCF por medio de técnicas percutáneas.

Minimally Invasive Therapies for Osteoarthritic Hip Pain: a Comprehensive Review.

PURPOSE OF REVIEW: Osteoarthritis (OA) is a highly prevalent cause of chronic hip pain, affecting 27% of adults aged over 45 years and 42% of adults aged over 75 years. Though OA has traditionally been described as a disorder of "wear-and-tear," recent studies have expanded on this understanding to include a possible inflammatory etiology as well, damage to articular cartilage produces debris in the joint that is phagocytosed by synovial cells which leads to inflammation. RECENT FINDINGS: Patients with OA of the hip frequently have decreased quality of life due to pain and limited mobility though additional comorbidities of diabetes, cardiovascular disease, poor sleep quality, and obesity have been correlated. Initial treatment with conservative medical management can provide effective symptomatic relief. Physical therapy and exercise are important components of a multimodal approach to osteoarthritic hip pain. Patients with persistent pain may benefit from minimally invasive therapeutic approaches prior to consideration of undergoing total hip arthroplasty. The objective of this review is to provide an update of current minimally invasive therapies for the treatment of pain stemming from hip osteoarthritis; these include intra-articular injection of medication, regenerative therapies, and radiofrequency ablation.

Fascia and soft tissues innervation in the human hip and their possible role in post-surgical pain.

Persistent symptoms, most commonly pain, may remain after otherwise successful hip replacement surgery. Innervation of fascia and soft tissues has become increasingly important in etiopathogenesis of pain, but the relative importance of the various anatomical structures in the hip region is still not known. Innervation of skin, superficial adipose tissue, superficial fascia, deep adipose tissue, deep fascia, muscles, capsule, capsule ligament, ligamentum teres, and tendon in the human hip from 11 patients and 2 cadavers were quantified by staining with anti-S100 antibody for myelin-forming Schwann cells, to obtain the percentage of antibody positivity, density and mean diameter of the nerve fibers. The skin was the most highly innervated (0.73% ± 0.37% of positive area in patients; 0.80% ± 0.28% in cadavers); the tendon was the least innervated (0.07% ± 0.01% in patients, 0.07% ± 0.007% in cadavers). The muscles (vasto-lateral and gluteus medius) were the second most innervated structure according the percentage (0.31% ± 0.13% in living humans, 0.30% ± 0.07% in cadavers), but with only a few nerves, with large diameters (mean diameter 36.4 ± 13.4 µm). Instead, the superficial fasciae showed 0.22% ± 0.06% and 0.26% ± 0.05% of positive areas in living humans and cadavers, respectively. Fasciae were invaded by networks of small nerve fibers, revealing a possible role in pain. The superficial fascia was the second most highly innervated tissue after the skin, with a density of 33.0 ± 2.5/cm2 , and a mean nerve sizes of 19.1 ± 7.2 µm. Lastly, the capsule turned out to be poorly innervated (0.09%), showing that its removal does not necessarily lead to painful consequences. Statement of clinical significance: Deeper knowledge about the innervation of the soft tissue in the human hip joint will enhance study and understanding of the best surgical procedures to follow during hip arthroplasty to reduce post-operative pain.

Innervation of the hip joint capsular complex: A systematic review of histological and immunohistochemical studies and their clinical implications for contemporary treatment strategies in total hip arthroplasty.

The hip joint capsule contributes to the stability of the hip joint and lower extremity, yet this structure is incised and often removed during total hip arthroplasty (THA). Increasing incidence of osteoarthritis is accompanied by a dramatic rise in THAs over the last few decades. Consequently, to improve this treatment, THA with capsular repair has evolved. This partial restoration of physiological hip stability has resulted in a substantial reduction in post-operative dislocation rates compared to conventional THA without capsular repair. A further reason for the success of this procedure is thought to be the preservation of the innervation of the capsule. A systematic review of studies investigating the innervation of the hip joint capsular complex and pseudocapsule with histological techniques was performed, as this is not well established. The literature was sought from databases Amed, Embase and Medline via OVID, PubMed, ScienceDirect, Scopus and Web of Science; excluding articles without a histological component and those involving animals. A total of 21 articles on the topic were identified. The literature indicates two primary outcomes and potential clinical implications of the innervation of the capsule. Firstly, a role in the mechanics of the hip joint, as mechanoreceptors may be present in the capsule. However, the nomenclature used to describe the distribution of the innervation is inconsistent. Furthermore, the current literature is unable to reliably confirm the proprioceptive role of the capsule, as no immunohistochemical study to date has reported type I-III mechanoreceptors in the capsule. Secondly, the capsule may play a role in pain perception, as the density of innervation appears to be altered in painful individuals. Also, increasing age may indicate requirements for different strategies to surgically manage the hip capsule. However, this requires further study, as well as the role of innervation according to sex, specific pathology and other morphometric variables. Increased understanding may highlight the requirement for capsular repair following THA, how this technique may be developed and the contribution of the capsule to joint function and stability.

Applications and critical evaluation of fascia iliaca compartment block and quadratus lumborum block for orthopedic procedures.

Anterior section of the hip joint capsule is innervated by femoral nerve and obturator nerve, and posterior section is innervated by the nerve to quadratus femoris muscle and occasionally by the superior gluteal (posterolateral region) and sciatic nerve (posterosuperior region). One of the regional anesthesia options for hip surgery is the fascia iliaca compartment block (FICB) that affects nerves important for hip innervation and sensory innervation of the thigh - femoral, obturator and lateral femoral cutaneous nerve. FICB can be easily performed and is often a good solution for management of hip fractures in emergency departments. Its use reduces morphine pre-operative requirement for patients with femoral neck fractures and can also be indicated for hip arthroplasty, hip arthroscopy and burn management of the region. Quadratus lumborum block (QLB) is a block of the posterior abdominal wall performed exclusively under ultrasound guidance, with still unclarified mechanism of action. When considering hip surgery and postoperative management, the anterior QLB has shown to reduce lengthy hospital stay and opioid use, it improves perioperative analgesia in patients undergoing hip and proximal femoral surgery compared to standard intravenous analgesia regimen, provides early and rapid pain relief and allows early ambulation, thus preventing deep vein thrombosis and thromboembolic complications etc. However, some nerve branches responsible for innervation of the hip joint are not affected by QLB, which has to be taken into consideration. QLB has shown potential for use in hip surgery and perioperative pain management, but still needs to be validated as a reliable treatment approach.

A Review of Current Denervation Techniques for Chronic Hip Pain: Anatomical and Technical Considerations.

PURPOSE OF REVIEW: Percutaneous radiofrequency (RF) denervation of articular sensory nerves of the hip joint is a minimally invasive neurotomy technique that can provide pain relief in patients with chronic hip pain. There has been an increase in the number of publications on RF denervation of the hip over the last few years although many questions remain regarding anatomical targets, technical aspects, selection criteria, and evidence for effectiveness. RECENT FINDINGS: For this updated review, publications were identified by searching MEDLINE and other medical literature databases from inception through November 30, 2018. Existing knowledge of hip joint innervation was reviewed and data on patient selection, prognostication of analgesic benefit from ablation by using local anesthetic blocks, current techniques of performing hip joint ablation, analgesic success, functional outcomes, and adverse effects were critically reviewed and analyzed. Sensory denervation of the anterior hip joint using RF current is a viable treatment option for management of chronic hip pain after conservative methods fails to do so. We have synthesized knowledge from papers on techniques of ablation and from recently elaborated anatomical details. We also provide suggestions regarding anticipated outcomes of the procedure. Our review of existing literature indicates evidence for analgesic benefits, improvement in function, and a low incidence of adverse effects of RF ablation of sensory innervation to the hip joint. Future research should focus on refining the technique of ablation and monitoring of long-term outcomes.

Limping on split-belt treadmills implies opposite kinematic and dynamic lower limb asymmetries.

Walking on a split-belt treadmill (each of the two belts running at a different speed) has been proposed as an experimental paradigm to investigate the flexibility of the neural control of gait and as a form of therapeutic exercise. However, the scarcity of dynamic investigations challenges the validity of the available findings. The aim of the present study was to investigate the dynamic asymmetries of lower limbs of healthy adults during adaptation to gait on a split-belt treadmill. Ten healthy adults walked on a split-belt treadmill mounted on force sensors, with belts running either at the same speed ('tied' condition) or at different speeds ('split' condition, 0.4 vs. 0.8 or 0.8 vs. 1.2 m/s). The sagittal power and work provided by ankle, knee and hip joints, joint rotations, muscle lengthening, and surface electromyography were recorded simultaneously. Various tied/split walking sequences were requested. In the split condition a marked asymmetry between the parameters recorded from each of the two lower limbs, in particular from the ankle joint, was recorded. The work provided by the ankle (the main engine of body propulsion) was 4.8 and 2.2 times higher (in the 0.4 vs. 0.8, and 0.8 vs. 1.2 m/s conditions, respectively) compared with the slower side, and 1.2 and 1.1 times higher compared with the same speed in the tied condition. Compared with overground gait in hemiplegia, split gait entails an opposite spatial and dynamic asymmetry. The faster leg mimics the paretic limb temporally, but the unimpaired limb from the spatial and dynamic point of view. These differences challenge the proposed protocols of split gait as forms of therapeutic exercise.

Ultrasound-Guided Pericapsular Hip Joint Alcohol Neurolysis for the Treatment of Hip Pain: A Case Report of a Novel Approach.

Severe pain after a hip fracture commonly delays hospital discharge and poses significant nursing problems in patients who are not surgical candidates. We present ultrasound-guided pericapsular hip alcohol neurolysis of the articular branches of the femoral and obturator nerves as a novel approach in the treatment of severe pain after hip fracture. This technique provided excellent pain relief in a 94-year-old patient with intertrochanteric hip fracture until her death 2 months later.

Anatomical study of the articular branches innervated the hip and knee joint with reference to mechanism of referral pain in hip joint disease patients.

INTRODUCTION: Referred pain in the anterior knee joint is the most common symptom in hip disease patients. The development of referred pain is considered to be related to dichotomizing peripheral sensory fibers. However, no gross anatomical findings identify any dichotomizing fibers innervating both the hip and knee joints. We dissected the femoral and obturator nerves in human cadavers to investigate the distribution of the articular branches in the hip and knee joints. Fourteen embalmed left lower limbs from 14 Japanese adult cadavers (five from females, nine from males, average age 73.8 ± 14.1 years) were observed macroscopically. The articular branches of the femoral and obturator nerves were dissected at the anterior margin of the groin toward the thigh region. After dissections of the articular nerves of the hip joints, the femoral and obturator nerves were exposed from proximally to distally to identify the articular nerves of the knee joints. The branching pattern of the articular branches in the hip and knee joints was recorded. In six of 14 limbs (42.9%), the femoral nerve supplied articular branches to the anteromedial aspect of both the hip and knee joints. These articular branches were derived from the same bundle of femoral nerve. These gross anatomical findings suggested that dichotomizing peripheral sensory fibers innervate the hip and knee joints and these could relate to the referred pain confirmed in the anterior knee joints of patients with hip disease. Clin. Anat. 31:705-709, 2018. © 2018 Wiley Periodicals, Inc.

Efficacy of lateral- versus medial-approach hip joint capsule denervation as surgical treatments of the hip joint pain; a neuronal tract tracing study in the sheep.

OBJECTIVE: To evaluate efficacy of denervation of the of the hip joint capsule (HJC), as a treatment of hip joint pain. Specifically, we tested the hypothesis that HJC denervation will significantly reduce the number of sensory neurons innervating the capsule. STUDY DESIGN: Denervation of the HJC from a medial or lateral approach was followed by retrograde tracing of sensory neurons innervating the capsule. ANIMALS: Twenty adult male sheep (30-40 kg of body weight; Polish merino breed) were used in the study. METHODS: The hip joint was denervated from medial (n = 5) or lateral (n = 5) surgical approaches. Immediately after denervation, the retrograde neural tract tracer Fast Blue (FB) was injected into the HJC. An additional ten animals (n = 5 for medial and n = 5 for lateral approach) received the same treatment without HJC denervation to provide the appropriate controls. RESULTS: Results of the study revealed that the vast majority of retrogradely labelled sensory neurons innervating the HJC originate from fifth lumbar to second sacral dorsal root ganglia. Both the medial and the lateral denervations significantly reduced the number of sensory neurons innervating the HJC (39.2% and 69.0% reduction respectively). CONCLUSIONS: These results show that denervation of the HJC is an effective surgical procedure for reduction of the sensory neuronal input to the HJC. Moreover, the lateral approach was found to be significantly more effective for reducing sensory innervation as compared to the medial one.

Pudendal nerve injury is a relatively common but transient complication of hip arthroscopy.

PURPOSE: Hip arthroscopy is emerging as the standard of care for conditions involving the hip, and has a unique set of complications. The purpose of this review was to identify (1) the crude rate of pudendal nerve injury following hip arthroscopy and (2) the specific factors leading to pudendal nerve injury. METHODS: MEDLINE, EMBASE, and PubMed were searched from database inception to October 2016. Patient demographics, indications, surgical technique, complication rates, treatment approaches, and rehabilitation strategies were extracted. RESULTS: Twenty-four studies (n = 3405) were included, with the majority (66%) of studies being level IV evidence. The mean age was 33.9 ± 9.7 years (range 12-78) and 48.2% were males. Average follow-up was 30.2 ± 19.1 months. 62 patients were reported to have sustained pudendal nerve injury (1.8%) post-operatively, and all resolved within 6 weeks to 3 months. Of the seven studies that reported using a perineal post, 20 patients were diagnosed with pudendal nerve injury (4.3%), in contrast to two studies (189 patients) reporting only 0.5% pudendal nerve injury without the use of perineal post. Two studies commented on time of traction during surgical intervention with mean times of 98 and 68 min with complication rates of 10% and 6.6%, respectively. CONCLUSIONS: Pudendal nerve injury is not uncommon following hip arthroscopy, with a reported rate found in this review of 1.8%. Potential risk factors may include the use of a perineal post and long traction times. All reported cases resolved within 3 months. Patients should be informed of complications related to pudendal nerve injury, which include sexual and urinary dysfunction. LEVEL OF EVIDENCE: Level IV, systematic review of level I-IV studies.

Radiofrequency Procedures to Relieve Chronic Hip Pain: An Evidence-Based Narrative Review.

BACKGROUND AND OBJECTIVES: Chronic hip pain from osteoarthritis and other degenerative conditions is a common problem. A few publications have recently reported analgesic success of radiofrequency (RF) procedures on nerves innervating the hip, but interpretation is hampered by lack of clarity regarding indications, clinical protocols, anatomic targets, and longevity of benefit from RF procedures. METHODS: We reviewed the following medical literature databases for publications on RF procedures on the hip joint for chronic pain: MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Google Scholar through February 28, 2017. Existing knowledge on innervation of the hip joint was synthesized. Data on analgesic and functional outcomes and adverse effects measured at any time points following the interventions were also collected, analyzed, and reported in this narrative review. RESULTS: Fourteen publications on ablative RF treatments of innervation of the hip joint were identified. A high success rate of these procedures in relieving chronic pain of the hip joint was reported at 8 days to 36 months after the procedures, but none of the publications were randomized controlled trials. There was evidence for improvement in function and a lack of serious adverse events of RF treatments. CONCLUSIONS: Radiofrequency treatments for the sensory innervation of the hip joint have the potential to reduce pain secondary to degenerative conditions. Ongoing concerns remain regarding the anatomic targets, as well as quality, procedural aspects, and monitoring of outcomes in publications on this topic. Randomized controlled trials of high methodological quality are required to further elaborate the role of these interventions in this population.

Anatomic Study of Innervation of the Anterior Hip Capsule: Implication for Image-Guided Intervention.

BACKGROUND AND OBJECTIVES: The purpose of this cadaveric study was to determine the pattern of anterior hip capsule innervation and the associated bony landmarks for image-guided radiofrequency denervation. METHODS: Thirteen hemipelvises were dissected to identify innervation of the anterior hip capsule. The femoral (FN), obturator (ON), and accessory obturator (AON) nerves were traced distally, and branches supplying the anterior capsule documented. The relationships of the branches to bony landmarks potentially visible with ultrasound were identified. RESULTS: The anterior hip capsule received innervation from the FNs and ONs in all specimens and the AON in 7 of 13 specimens. High branches of the FN (originating above the inguinal ligament) were found exclusively in 12 specimens and passed between the anterior inferior iliac spine and the iliopubic eminence. The ONs were innervated exclusively by high branches (proximal to the division), by low branches (from the posterior branch), and by both in 4, 5, and 4 specimens, respectively. The most consistent landmark was the inferomedial acetabulum (radiographic "teardrop"). When present, the AON coursed over the iliopubic eminence before innervating the anterior hip capsule. CONCLUSIONS: Branches of the FNs and ONs consistently provided innervation to the anterior hip capsule. The AON also contributed innervation in many specimens. The relationship of the articular branches from these 3 nerves to the inferomedial acetabulum and the space between the anterior inferior iliac spine and iliopubic eminence may suggest potential sites for radiofrequency ablation.