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.

We believe that the technique using "tunnel vision" with anatomically appropriate cannula placement and use of a large-bore, curved needle with a 10-mm active tip may improve the results of radiofrequency denervation of lumbar zygapophysial joints. Providing a detailed description of an anatomically accurate technique should be of value to those seeking to perform this procedure in a valid manner.

Background and objectivesPeripheral nerve block is an important component of the multimodal analgesia for total knee arthroplasty. Novel interventional techniques of ultrasound-guided nerve block supplying the posterior knee joint capsule require knowledge of the innervation of the posterior capsule. The objectives of this cadaveric study were to determine the course, frequency, and distribution of the articular branches innervating the posterior knee joint capsule and their relationships to anatomical landmarks.MethodsFifteen lightly embalmed specimens were meticulously dissected. The origin of articular branches was identified, their frequency recorded, and the course documented in relation to anatomical landmarks. The capsular distribution of articular branches was documented and a frequency map generated.ResultsIn all specimens, articular branches from the posterior division of the obturator and tibial nerves were found to supply the posterior capsule. Additionally, articular branches from common fibular nerve and sciatic nerve were found in eight (53%) and three (20%) specimens, respectively. The capsular distribution of tibial nerve spanned the entire posterior capsule. The posterior division of obturator nerve supplied the superomedial aspect of the posterior capsule overlapping with the tibial nerve. The superolateral aspect of the posterior capsule was innervated by the tibial nerve and, when present, the common fibular/sciatic nerves.ConclusionsFrequency map of the course and distribution of the articular branches and their relationship to anatomical landmarks form an anatomical basis for peripheral nerve block approaches that provide analgesia to the posterior knee joint capsule.

The frequency map of the articular branches provides an anatomical basis for the development of new clinical protocols for knee radiofrequency denervation and perioperative pain management.

Adding clonidine to a TAP block with bupivacaine did not affect wound hyperalgesia index and it did not improve short-term or long-term pain scores in women undergoing elective cesarean delivery. Further studies are warranted to determine the benefits of antihyperalgesic adjuvants in TAP solutions for specific individuals at risk for chronic pain.