Professional information for physicians and medical professionals. This article reviews the current evidence and does not replace guidelines or individual medical decision-making. Research status: September 2026.
Image-guided PRP injection
For small, deep or anatomically confined target spaces, the position of the needle tip can determine whether a preparation is actually delivered where intended. Ultrasound and fluoroscopy monitor this position in different ways.
With an ultrasound-guided PRP injection soft tissues, the needle and adjacent vessels or nerves can be visualised in real time. A fluoroscopy-guided PRP injection is oriented primarily to bony structures; contrast medium can additionally confirm the position in joint, disc or epidural spaces.
The key scientific distinction is this: image guidance can increase targeting accuracy . Whether this also improves the clinical outcome of a PRP treatment is a separate question and has so far been studied directly for only a few indications.
Out of 100 injections, how many reach the joint …
Select an approach or imaging method.
Knee, without image guidance
Sacroiliac joint, with image guidance
75 %intra-articular
Anteromedial approach without image guidance; position checked fluoroscopically. Jackson et al. 2002
Hits: landmark guidance Hits: image guidance outside the joint
Summary
Accuracy depends on the target and approach.At the knee, favourable landmark-guided approaches achieve high accuracy rates, while others perform substantially worse. Image guidance improves accuracy in many musculoskeletal interventions.24
Not all imaging is the same.EULAR favours ultrasound for targeted interventions at peripheral joints and nerves. For the spine and sacroiliac joint, the modality should be selected according to the target structure, procedure, experience, availability and radiation exposure.25
Direct PRP comparisons exist – but only a few.In lateral epicondylitis, a randomised study found no clinical advantage of ultrasound guidance; a small randomised temporomandibular-joint study from 2026, by contrast, found greater placement accuracy and better trajectories for some outcomes.26,27
Precision is not the same as efficacy.A correctly placed injection does not prove that PRP is effective for the respective indication. Preparation, application and clinical effect must be assessed separately.
Background
Greater anatomical precision does not automatically lead to a better clinical result with every injectate. In a double-blind rotator-cuff study, for example, an ultrasound-guided subacromial steroid injection was not significantly more effective than the same dose given systemically by intramuscular injection7. Such steroid data cannot be transferred to PRP, but they show why placement accuracy and clinical outcome must be studied separately.
For PRP, a local effect is biologically plausible: platelets and released mediators are initially present where the preparation is applied. This does not automatically mean, however, that every millimetre-perfect placement is clinically superior. So far, this question has been examined in only a few direct PRP comparison studies.26,27
Imaging can also provide information beyond the needle position itself: ultrasound can show effusions, tendon structure, vessels and nerves, for example. An effusion changes volume and distribution within a joint; this alone does not prove that aspiration before PRP improves the clinical outcome. The quality of PRP preparation and the quality of application remain two separate process steps.
Accuracy
The most frequently cited knee study is by Jackson and colleagues. An experienced orthopaedic surgeon performed 240 injections into knees without effusion, 80 through each of three approaches, and subsequently checked the position fluoroscopically with contrast medium. The intra-articular rates were 93 percent for the lateral mid-patellar approach, 75 percent for the anteromedial approach and 71 percent for the anterolateral approach1.
A systematic review of 23 publications confirms the pattern2. Pooled data showed the superolateral approach without image guidance to be the most accurate at 87 percent, while the medial mid-patellar approach was least accurate at 64 percent. Overall, roughly one in five blind knee injections was extra-articular. Image-guided injections were moderately more accurate, particularly with less favourable approaches. Experienced injectors achieved good results without imaging using the superolateral approach.
The deeper and more obscured by bone the target, the larger the difference can become. At the sacroiliac joint, a prospective randomised study directly compared ultrasound and fluoroscopy: 87.3 percent of ultrasound-guided and 98.2 percent of fluoroscopy-guided injections were intra-articular8.
A broader systematic EULAR review of 66 studies, including 49 randomised trials, points in the same direction: image-guided procedures were more accurate than palpation or anatomical landmarks in many comparisons. The authors nevertheless emphasised study heterogeneity and frequently moderate-to-high risk of bias; direct comparisons of imaging methods did not identify one universally superior modality.24
The American Medical Society for Sports Medicine also summarised the literature in 2015. Ultrasound-guided injections were rated as more accurate than landmark-guided injections (SORT A), while evidence for efficacy and cost-effectiveness was weaker (SORT B).3 The newer EULAR Points to Consider therefore take a target-specific approach: ultrasound is preferred for peripheral joints and nerves, while the imaging modality for the spine and sacroiliac joint should be selected individually.25
Interpretation
Whether the needle reaches the intended structure is a technical endpoint. Whether the patient gains additional clinical benefit is a different endpoint. This distinction is central to PRP.
A direct randomised PRP study in chronic lateral epicondylitis compared 30 palpation-guided with 30 ultrasound-guided injections. Pain, DASH score and grip strength improved in both groups; there was no significant difference between the techniques after one, three or six months.26
A small randomised temporomandibular-joint study from 2026 produced a different result. In 64 patients, placement after the PRP injection was checked fluoroscopically with contrast medium. Ultrasound achieved 32 of 32 correct placements, compared with 22 of 32 with palpation (100% vs. 68.8%). For some pain and functional parameters, the ultrasound group showed advantages after three or six months.27 Because of the small sample, the single operator and the specific target region, this does not establish a general superiority of ultrasound-guided PRP.
PRP studies in which imaging is standardised in both groups also underline the need to separate application from efficacy. In chronic Achilles tendinopathy, ultrasound-guided PRP was no better than the respective control treatment in randomised studies.10,11 Precise application can reduce one methodological source of error, but it does not replace evidence of efficacy for the indication.
Direct PRP data: available, but limited
The statement that “there are no direct comparison studies” is no longer tenable. Randomised data exist at least for lateral epicondylitis and the temporomandibular joint, with differing results.26,27 This is not enough for a robust, indication-independent conclusion. Standardised reporting of the PRP preparation and application also remains important; the MIBO checklist was developed in part for this purpose.20
Ultrasound
High-frequency linear probes are used for superficial targets such as tendons, knee, elbow and shoulder. They provide fine resolution but lose image quality with increasing depth. For the hip and for patients with a greater soft-tissue depth, lower-frequency curved-array probes penetrate more deeply at the cost of lower resolution.
Two techniques are distinguished for needle guidance. In-Plane the needle runs within the ultrasound plane and can be seen along its full length. Out-of-Plane the needle crosses the plane and appears only as a bright point, making it easy to mistake the shaft for the tip. The steeper the insertion angle, the less ultrasound is reflected back from the needle to the probe.
The practical advantage is the moving image: the target structure and needle can be observed during advancement, and distribution of the injectate can often be followed sonographically depending on the tissue and target space. If the observed distribution pattern does not match the intended target, the position can be reassessed. Doppler techniques can also show vessels along the planned needle path.
For peripheral joints and nerves, the EULAR Points to Consider favour ultrasound over other imaging modalities.25 The widespread use of ultrasound in PRP research is also shown by a systematic review of tendinopathies including 33 randomised studies and 2,025 participants.28 These studies do not automatically prove that ultrasound itself causes the PRP effect.
Fluoroscopy
Under a C-arm, the needle and bony landmarks are directly visible. In many intra-articular and spinal interventions, a small amount of iodinated contrast medium is additionally used to assess the distribution pattern in the intended target space and to identify signs of unintended vascular or intrathecal placement. Contrast medium therefore supplements anatomical needle control; it is not required in the same way for every fluoroscopic procedure.
One important point: PRP is not radiopaque and therefore cannot be seen directly under fluoroscopy as its own contrast agent. If contrast medium is used beforehand, its pattern confirms the position or accessible target space; the subsequent distribution of PRP itself is not directly visualised by this.
PRP-specific fluoroscopy data come mainly from axial and deep target regions. In discogenic low-back pain, a small double-blind randomised trial reported short-term advantages after intradiscal PRP compared with the control group.13 For lumbar intradiscal and epidural PRP procedures, the 2025 ASIPP guideline rates the evidence as Level III (“fair”), and for facet and sacroiliac joints as Level IV (“limited”).30
The sacroiliac joint also illustrates why technical precision and efficacy must remain separate: in a double-blind fluoroscopy-guided RCT with 26 patients, both PRP and corticosteroid groups improved, but PRP was not superior to steroid.29 A 2026 meta-analysis of ten randomised or quasi-randomised studies on facet and SI-joint pain found some later pain outcomes favouring PRP, but still judged the overall evidence inconclusive.31
CT can be an alternative for selected spinal interventions, such as interlaminar epidural PRP injections.15 Conversely, ultrasound has also been studied in a randomised trial for transforaminal PRP injections.21 The methods are therefore not universally interchangeable; target structure, intervention, experience, equipment availability and radiation exposure should be considered together.25
Radiation protection in Germany
For the medical use of ionising radiation, a justified indication by a physician or dentist with the required radiation-protection expertise is mandatory (§ 83 StrlSchG). The Radiation Protection Ordinance further specifies, among other things, the assessment of the procedure or a treatment attempt requiring special justification and the requirements for technical performance (§§ 119, 145 StrlSchV).22 Exposure must be limited as far as medically reasonable.
Target structure
The choice depends on more than depth. The target structure, planned procedure, anatomical overlap, operator experience, equipment availability and, for X-ray procedures, radiation exposure all interact.25 The following assignment is therefore a practical orientation, not a procedural requirement.
Soft tissues and peripheral joints
Axial skeleton and bone
Location of target structure: Superficial
Hypoechoic areas, tears and neovascularisation on power Doppler can be visualised directly. Imaging can distinguish whether the preparation is delivered intratendinously or into the paratenon.
The suprapatellar recess is readily visualised. An effusion can be identified and, when clinically indicated, aspirated before PRP administration; whether this improves outcomes is a separate question.
Without image guidance, roughly one in five injections was extra-articular; image-guided injections were moderately more accurate, especially with medial mid-patellar and anterolateral approaches2.
In a dry osteoarthritic knee, an effusion is unavailable as a landmark. Anteromedial and anterolateral approaches are substantially less reliable without imaging than the lateral mid-patellar approach1.
The subacromial bursa and tendon lesion can be seen in the same field of view. Intratendinous targets can be approached selectively.
For corticosteroids, image guidance showed no clinically relevant advantage6; systemic administration was also not significantly inferior to subacromial injection7.
These steroid data cannot simply be transferred to PRP because PRP is intended to act locally. Direct comparative PRP data for this target region are lacking.
The joint space lies beneath substantial musculature. With a posterior in-plane approach, the needle can be followed to the joint space.
According to the AMSSM position statement, ultrasound-guided injections are more accurate than landmark-guided injections3.
In muscular or obese patients, a linear probe can reach its limits; a curved-array probe or fluoroscopy may then be alternatives.
The joint lies deep, with the femoral neurovascular bundle in close proximity. Sonographically, an anterior approach targets the head-neck junction while the bundle is visualised.
Image guidance is considered standard at the hip; the greater accuracy of ultrasound-guided injections is well supported3.
A steep insertion angle reduces needle visibility. Fluoroscopy can confirm position robustly but requires radiation and contrast medium.
The joint space is obliquely oriented and partly obscured by bone. A contrast arthrogram can confirm intra-articular placement.
In the direct comparison, 98.2 percent of fluoroscopy-guided and 87.3 percent of ultrasound-guided injections were intra-articular8. In a randomised study, PRP was injected into the sacroiliac joint under ultrasound guidance12.
In the randomised comparison, the fluoroscopic intra-articular accuracy rate was higher. This does not prove that fluoroscopy is clinically superior for every SI-joint procedure; EULAR recommends a target- and procedure-specific choice.25
The small joints lie behind the bony contour of the vertebral arch. Position can be confirmed with an arthrogram.
PRP-specific data remain limited. The 2025 ASIPP guideline rates PRP for lumbar facet joints as evidence Level IV; a 2026 meta-analysis reports positive signals but still stresses the limited certainty of the evidence.30,31
Joint capacity is small. The volume of contrast medium and preparation must be adapted accordingly.
In fluoroscopic procedures, an epidurogram can show distribution within the epidural space and provide clues to unintended intravascular or intrathecal placement. Ultrasound and CT use different imaging principles.
Fluoroscopy-guided epidural injections with platelet lysate were evaluated in a registry case series14; CT-guided interlaminar epidural PRP injections in a non-randomised comparative study15. Ultrasound was studied in a randomised trial for transforaminal approaches.21 ASIPP rates epidural PRP as evidence Level III in 2025.30
The injectate in the registry study contained lidocaine and hydrocortisone in addition to lysate. The effects therefore cannot be attributed to the platelet product alone.
Intradiscal needle placement is controlled with imaging. Fluoroscopy or CT shows bony orientation and needle position; a contrast pattern can additionally document intradiscal location.
A small double-blind randomised study reported short-term advantages over control after fluoroscopy-guided intradiscal PRP.13 The 2025 ASIPP guideline rates the overall evidence for intradiscal PRP as Level III (“fair”).30
Discitis is the feared complication. Asepsis and infection-prevention measures must be clearly defined in the protocol.
In the published PRP technique, the trocar is advanced under fluoroscopy into defined subchondral bone regions. Bone contours and instrument position are well visualised radiographically.
The technique has been described and was investigated in a pilot study of 14 patients with severe knee osteoarthritis16,17.
These are uncontrolled pilot data. Controlled studies are still needed.
Evidence
Filter by imaging modality and study type. Note the label at the top right: many statements on accuracy do not come from PRP studies.
Imaging
Study type
Loading study overview
There are no entries in the overview for this combination. Select a different imaging modality or study type.
240 knee injections without effusion, one investigator, position checked fluoroscopically
Intra-articular: lateral mid-patellar 93%, anteromedial 75%, anterolateral 71%.1
Systematic review, 23 publications
Without imaging, roughly one in five injections was extra-articular; image guidance was moderately more accurate. Ultrasound showed better short-term, but not long-term, outcomes.2
Position statement based on a systematic review
Ultrasound-guided injections more accurate (Grade A), more effective (Grade B) and more cost-effective (Grade B) than landmark-guided injections.3
Randomised study, 148 joints, triamcinolone, two-week follow-up
With ultrasound guidance: 43% less procedural pain, higher responder rate, and effusions detected more often.4
Double-blind randomised trial, rotator cuff
Ultrasound-guided subacromial injection was not significantly more effective than systemic injection into the gluteal muscle.7
Systematic review, update of Bloom et al. 2012
No clinically relevant advantage of image-guided over blind glucocorticoid injection for shoulder pain.5,6
Prospective randomised study, sacroiliac joint
Intra-articular: fluoroscopy 98.2%, ultrasound 87.3%.8
Double-blind randomised study, 23 patients, patellar tendinopathy
Dry needling plus leukocyte-rich PRP was better than dry needling alone at 12 weeks; no significant difference at 26 weeks.9
Randomised study, 54 patients, chronic Achilles tendinopathy
Ultrasound-guided PRP was no better than saline after 24 weeks; both groups also performed eccentric training.10
Multicentre randomised study, 240 patients, Achilles tendinopathy
No difference between PRP and sham injection in VISA-A at six months (54.4 vs. 53.4 points).11
Randomised study, 40 patients, sacroiliac joint
Ultrasound-guided PRP produced lower pain scores than methylprednisolone after six weeks and three months.12
Double-blind randomised study, 47 patients, discogenic low-back pain
Intradiscal PRP showed greater improvement in pain, function and satisfaction after eight weeks than the contrast-medium control group.13
Registry case series, 470 patients, 13 centres, no control group, industry-funded
Epidural platelet lysate under C-arm fluoroscopy with contrast confirmation; pain and function improved. The injectate additionally contained lidocaine and hydrocortisone.14
Pilot study, 14 patients, severe knee osteoarthritis
Combined intra-articular and subchondral PRP under fluoroscopy; KOOS pain increased from 61.6 to 74.6 points at six months.16
Non-randomised comparative study, 60 patients, lumbar radicular pain
CT-guided interlaminar epidural injection: both PRP and steroid groups improved significantly after six weeks.15
Prospective randomised study, lumbar disc herniation
Ultrasound-guided transforaminal PRP injection compared with steroid; demonstrates that ultrasound is also used at the lumbar spine.21
Laboratory study with PRP and iodinated contrast media
Iodixanol and iopamidol had no significant effect on PRP function at an early time point.18
Laboratory study of local anaesthetics and platelet function
Bupivacaine 0.75% adversely affected platelets; lidocaine 1% and ropivacaine 0.5% were comparatively well tolerated at mixing ratios up to 1:1.19
66 studies, 49 of them randomised; various musculoskeletal interventions
Imaging increased placement accuracy compared with palpation in many comparisons. The studies were heterogeneous; no universally best imaging modality could be identified.24
EULAR Points to Consider for image-guided musculoskeletal interventions
Ultrasound is preferred for peripheral joints and nerves; at the spine and SI joint the modality should be chosen according to target, procedure, expertise, availability and radiation exposure.25
Randomised, 60 patients, chronic lateral epicondylitis
Ultrasound- and palpation-guided PRP both improved VAS, DASH and grip strength; no significant difference between groups at 1, 3 or 6 months.26
Randomised, 64 patients, temporomandibular joint; position subsequently checked fluoroscopically
Correct placement 100% (32/32) with ultrasound versus 68.8% (22/32) with palpation; ultrasound group had advantages for some clinical endpoints. Small single-centre study.27
33 randomised studies, 2,025 participants, tendinopathies and related indications
Shows the broad use of ultrasound-guided PRP injections in studies. The review does not, however, test ultrasound guidance as an isolated efficacy variable.28
Double-blind, 26 patients, fluoroscopy-guided SI-joint injection
Both PRP and corticosteroid groups improved; PRP was not superior to steroid. Precise image guidance therefore does not automatically establish efficacy of the injected preparation.29
Evidence-based guideline on regenerative procedures for chronic low-back pain
PRP: intradiscal and epidural evidence Level III (“fair”); facet and SI joint evidence Level IV (“limited”).30
10 randomised or quasi-randomised studies, 392 patients, facet and SI-joint pain
Some later pain endpoints favoured PRP; because of the limited data, the authors still regard the evidence as inconclusive.31
Procedure details
Depending on the procedure, additional substances may be part of the workflow. Iodinated contrast medium is used mainly for position control in fluoroscopic or CT-guided interventions. Local anaesthetics, by contrast, are not specific to imaging and can be used regardless of the selected imaging modality. Available data on direct contact with PRP come predominantly from laboratory studies.
Lidocaine 1% and ropivacaine 0.5% showed comparatively small effects on platelets in the laboratory at PRP mixing ratios up to 1:119.
Clinical data supporting a general mixing protocol for PRP and local anaesthetics are lacking. The epidural lysate registry study, for example, used 4% lidocaine, a different concentration from the laboratory study.14 Laboratory results must therefore not be extrapolated to arbitrary concentrations or PRP systems.
Bupivacaine 0.75% reduced platelet viability and adhesion in the laboratory and increased apoptosis and oxidative stress19.
These data do not establish an application rule, but they do define a clear point to consider: when PRP is combined with a local anaesthetic, the substance and concentration should be selected deliberately and documented in the protocol.
Iodixanol and iopamidol did not significantly change PRP concentration, activation or degranulation at an early time point18.
The study provides a reassuring short-term laboratory signal, but not clinical approval for arbitrary combinations. It examined specific iodinated contrast media and early time points; other products, concentrations, contact times and clinical endpoints are not covered.
Laboratory findings are not treatment recommendations. Whether and with what PRP is combined is a decision for the treating physician, taking into account the preparation system manufacturer's instructions.
Workflow
The following workflow is a schematic comparison, not a treatment protocol. Required steps depend on the target structure, imaging modality, product information and professional standards for the respective intervention. Our PRP cost-benefit analysis.
Define the target structure, preparation and procedure and obtain informed consent from the patient. In addition: a justified indication by a physician with radiation-protection expertise.
Visualise the target structure, effusion and needle path sonographically; identify vessels with power Doppler.Position the patient, set the target segment and define the beam angle for the bony landmark.
Collect blood and centrifuge according to the validated protocol of the system, timed so that the preparation is ready when the needle is in position. The manufacturer's permitted use period still applies if positioning takes longer. Protocol data, for example for Vi PRP-PRO and conversion to your centrifuge can be found in the RCF/RPM calculator.
Advance the needle under appropriate sterile conditions using the selected ultrasound technique; any planned aspiration depends on the indication and situation. Needle length and gauge must match the target depth and intervention.Advance under pulsed fluoroscopy and check the position in a second plane. Needle length and gauge select to match the target depth.
Observe the first tenths of a millilitre: distribution in the target space is visible and malposition can be corrected immediately.If required for the procedure, use contrast medium for position control and assess its distribution pattern; then inject according to the relevant protocol. PRP itself is not radiopaque under fluoroscopy.
Still image or clip of needle position and distribution, plus approach, volume and preparation data.Image of contrast distribution, dose values as required by documentation rules, plus approach, volume and preparation data.
Legal framework
The preparation and use of autologous blood products may be relevant under medicinal-products law. Section 13(2b) of the German Medicines Act (AMG) provides an exemption from the manufacturing authorisation requirement for certain patient-specific preparation scenarios under the direct professional responsibility of a person authorised to practise medicine; Section 67 AMG contains notification requirements.23 Whether and how these conditions are met in a specific practice workflow must be assessed on the basis of the actual preparation and application concept.
For details on who may perform which steps, see Who may perform PRP treatment?
The use of ionising radiation is governed by the German Radiation Protection Act and Radiation Protection Ordinance. Requirements include, among other things, a justified indication, the necessary expertise or knowledge, and rules for performance and documentation.22
For ultrasound services within Germany's statutory health insurance system, the Ultrasound Agreement applies; independently of this, DEGUM levels provide a recognised qualification framework.
PRP is generally provided as a private medical service in Germany. Our practical guide to PRP billing under the GOÄ.
PRP tubes and centrifuges have a defined intended purpose for preparation. Injection site, imaging and technique are medical application decisions. For product selection, see How to identify suitable PRP tubes.
This overview does not constitute legal advice. The applicable regulations and guidance from the competent authorities and professional bodies are decisive.
Communication
Image guidance can be a technical quality feature of application, but it must not be equated with a guaranteed treatment outcome. The German Heilmittelwerbegesetz prohibits misleading claims, particularly regarding unproven effects (§ 3 HWG). In practice communication, technical precision and clinical efficacy should therefore be clearly distinguished:
If in doubt, have advertising claims reviewed legally before publication.
Frequently asked questions
There is no general legal requirement in Germany that every PRP injection be image-guided. Professionally, the choice depends on the target structure and procedure. For targeted musculoskeletal interventions, EULAR generally recommends imaging over palpation alone, favours ultrasound for peripheral joints and nerves, and calls for an individual choice of modality at the spine and sacroiliac joint.25
A general improvement has not been established. Direct randomised PRP comparisons exist but are rare and conflicting: in lateral epicondylitis ultrasound provided no additional clinical benefit over palpation, whereas a small temporomandibular-joint study from 2026 found greater placement accuracy and advantages for the ultrasound group in some later endpoints.26,27
PRP absorbs X-rays only slightly more than surrounding tissue. Needle position is therefore typically confirmed beforehand with a small amount of iodinated contrast medium; PRP distribution is inferred from the verified target space rather than directly visualised.
Fluoroscopy is particularly useful when bony landmarks or contrast-assisted confirmation of a deep target space are important. At the sacroiliac joint, intra-articular accuracy was higher with fluoroscopy than ultrasound in one randomised study (98.2% vs. 87.3%). This does not establish general clinical superiority; for the spine and SI joint, EULAR recommends a situation-specific choice.8,25
Evidence comes mainly from laboratory studies. At early measurement points, iodixanol and iopamidol did not significantly alter the studied PRP parameters; in vitro, bupivacaine 0.75% showed more unfavourable platelet effects than lidocaine 1% or ropivacaine 0.5%.18,19 No general clinical mixing or application protocol can be derived from these findings.
Further reading
Sources
prpmed.de supplies medical devices and consumables for PRP preparation. Indication, target structure, imaging and injection technique are the responsibility of the treating physician.