Aspiration and Injection Techniques of the Lower Extremity

Christopher P. Chiodo, MD; Catherine Logan, MD, MBA, MSPT; Cheri A. Blauwet, MD


J Am Acad Orthop Surg. 2018;26(15):e313-e320. 

In This Article

Hip and Knee Regions

Hip Joint

Intra-articular hip aspiration is commonly used to assist in the diagnosis of infection.[13,14] Septic hip arthritis is more common in the pediatric patient; however, the incidence in adults ranges from 2 to 10 per 100,000 person-years.[15]

Localizing the hip may be hindered both by body habitus and the inherently deep location of the joint. As such, image guidance, including fluoroscopy, CT, or US, is recommended. Anterior and lateral approaches have been described (Table 2). Smith et al[4] evaluated the accuracy of US-guided intra-articular injections performed in 30 native adult hips. An anterior approach was used, and body mass index ranged from 20 to 39 kg/m2. The authors reported an accuracy rate of 97%, which was confirmed by contrast-enhanced fluoroscopic examination performed by an independent observer. Meanwhile, Mei-Dan et al[16] investigated the accuracy and safety of hip injections without image guidance in 55 adults. The authors used an anterior approach, and the injections were performed before supine hip arthroscopy. The accuracy of needle insertion was assessed with an air arthrogram and by direct visualization with the arthroscope. A 93% success rate was reported, with female sex correlating with more difficult needle placement (P = 0.06). The proposed reasons for misplacement included a high-riding trochanter, increased femoral version, thick adipose tissue, and ilium morphology.

Knee Joint

Aspiration of the knee joint may be performed to assist in the diagnosis of both infectious and noninfectious effusions. Corticosteroid injection into the knee is used for both diagnostic and therapeutic purposes in a noninfectious, inflammatory process.[17] Commonly used approaches for knee aspiration include the suprapatellar, midpatellar, and infrapatellar approaches[18] (Table 2).

The knee joint may be accessed using manual palpation alone or with image guidance (Figures 1 and 2). Curtiss et al[19] evaluated the accuracy of US-guided and palpation-guided knee injections using the superolateral approach in a single-blinded, prospective study of 20 cadaver specimens. This study also compared the accuracy of a less-experienced clinician (ie, orthopaedic fellow) with a staff physician in the second decade of practice. US-guided knee injections were 100% accurate for both clinicians, whereas palpation-guided injections were markedly less accurate when comparing the fellow with the staff physician (55% versus 100%, respectively). A 2002 investigation by Jackson et al[20] studied the accuracy of palpation-guided needle placement in 240 consecutive injections through three commonly used knee joint portals: anteromedial, anterolateral, and lateral midpatellar. Confirmation of placement was performed with fluoroscopy. The authors reported that a lateral midpatellar injection was intra-articular 93% of the time and was more accurate than injections using either of the other two portals (71% and 75% for the anterolateral and anteromedial approaches, respectively). In a systematic review of 429 injections assessing the injection site, Daley et al[7] reported no notable difference between injection site approaches, with an average accuracy of 84% (range, 70% to 93%). With regard to imaging, an additional analysis of 660 knee injections, 75 of which were performed with image guidance (US), found that the accuracy of image-guided procedures was 99%, compared with 79% of injections performed without guidance.[7] Chi-square with Yates correction yielded a P value of <0.001 and relative risk of 1.246 (confidence interval between 1.392 and 1.117), supporting a statistically significant difference in the accuracy of image-guided versus nonguided injections.

Figure 1.

Photograph showing the palpation-guided suprapatellar approach to the knee joint at the superolateral border of the patella.

Figure 2.

Photograph showing the ultrasonography-guided suprapatellar approach to the knee joint at the superolateral border of the patella.

Proximal Tibiofibular Joint

The proximal tibiofibular joint (PTFJ) consists of the articulation between the medial aspect of the fibular head and the proximal posterolateral tibia. It is a less common and potentially overlooked etiology of lateral knee pain. Pathology at this location may be due to arthritis, injury, compression of the common peroneal nerve, or a symptomatic ganglion cyst.[21,22] Injection of the joint may be conducted for diagnostic and therapeutic purposes and performed by palpation alone or with image guidance. Positioning the patient in the lateral decubitus position with the knee slightly flexed may facilitate needle placement (Table 2; Figure 3). Smith et al[23] reported a comparison of palpation-guided injections and US-guided techniques for the PTFJ in a cadaver model. The authors reported 100% accuracy with image guidance versus 58% with a palpation-guided technique. Inaccurate placement was superficial and inferior to the PTFJ in all cases of unsuccessful injection, with extravasation into the adjacent musculature. Only two palpation-guided injections delivered all the fluid into the PTFJ (17%).[23]

Figure 3.

Photograph showing the ultrasonography-guided approach to aspiration or injection of the proximal tibiofibular joint.

Pes Anserine Bursa

The pes anserinus is a confluence of the sartorius, gracilis, and semitendinosus tendons onto the proximal anteromedial tibia. A potential bursa lies between the pes anserinus tendons and the more deeply located medial collateral ligament and/or medial tibia. Pain in the area of the pes anserine bursa is most commonly secondary to an inflammation of the bursa, tenosynovitis, or tendinopathy as a result of repetitive overuse or direct trauma. Injection may be considered as a diagnostic tool or as a treatment modality for recalcitrant pain.

The confluence and its bursa are best palpated on the anteromedial aspect of the proximal tibia. Alternatively, the tendons and bursa may be visualized using US. Patients are placed in the lateral decubitus position, with the knee slightly flexed to facilitate needle placement (Table 2). Despite the superficial location of the pes anserinus, unguided bursa injections have proved less accurate than US-guided injections. In a single-blinded, prospective study, Finnoff et al[8] reported a markedly different accuracy of 92% versus 17%, respectively, when comparing the US-guided versus palpation-guided technique in adult cadaver specimens.