Study points to safer landmark for canine stifle arthrocentesis
Bottom line
CURRENT BRIEF VERSION: Stifle arthrocentesis in dogs may be due for a technique rethink. In a new ex vivo study published in Veterinary Surgery, researchers compared two commonly used landmark-based approaches with two newer ones across 32 paired canine cadaver pelvic limbs. All four techniques reached the joint accurately, but the suprapatellar approach stood out for safety: it caused no iatrogenic articular cartilage injury, while the infrapatellar technique caused cartilage injury in 6 of 8 limbs, often on weightbearing cartilage. The lateral intercondylar notch approach, the technique most commonly reported by surveyed surgeons, also caused no cartilage injury in this study. The broader issue of iatrogenic tissue contact is not unique to stifle access: another recent ex vivo Veterinary Surgery study comparing arthroscopy- versus fluoroscopy-assisted minimally invasive acetabular fracture repair in dogs found both methods were feasible and achieved near-anatomic reductions, but minor superficial cartilage damage was common and sciatic nerve injury occurred once in each group. Together, the studies reinforce that procedural success does not fully capture tissue-level risk. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinary professionals, the study sharpens an old question around not just whether a stifle injection is accurate, but what it may contact on the way in. Prior literature has suggested intra-articular injections in dogs are generally safe in clinical use, with major adverse events appearing rare, but reviews have still flagged cartilage damage and septic arthritis as known procedural risks and emphasized sterile technique, synovial fluid confirmation, and, in some cases, ultrasound guidance. The acetabular fracture work adds a useful parallel from another minimally invasive orthopedic setting: even when reduction quality and feasibility are good, minor cartilage injury and occasional nerve injury can still occur. This stifle paper adds practical evidence that landmark choice alone may materially affect cartilage injury risk, which could influence how clinicians approach diagnostic taps and therapeutic injections in painful or osteoarthritic stifles. (pubmed.ncbi.nlm.nih.gov)
What to watch: The next step is in vivo validation to see whether the suprapatellar technique performs as well in live canine patients, where positioning, effusion, pain, and operator experience may change the picture. More broadly, these findings fit a growing push in small-animal orthopedics to judge minimally invasive techniques not just by feasibility and endpoint accuracy, but by what collateral tissue effects they may cause along the way. (pubmed.ncbi.nlm.nih.gov)
A new Veterinary Surgery study suggests the canine stifle’s safest landmark for arthrocentesis may not be the one many surgeons currently use. In an ex vivo comparison of four techniques, investigators found that all approaches were accurate, but the suprapatellar technique was the only novel method to combine full accuracy with no detected iatrogenic articular cartilage injury. By contrast, the infrapatellar approach showed a high rate of cartilage injury, including injury to weightbearing cartilage. (pubmed.ncbi.nlm.nih.gov)
The study arrives as intra-articular procedures become more common in dogs for both diagnosis and treatment, especially in osteoarthritis and sports medicine settings. A 2022 review on joint injection techniques noted that arthrocentesis and intra-articular injection carry recognized risks including transient soreness, cartilage damage, and, more rarely, septic arthritis, while also stressing the importance of sterile technique and confirming needle placement. A separate 2023 retrospective analysis of 505 therapeutic joint injections in 178 client-owned dogs found major adverse effects were uncommon, with transient soreness the most frequent issue and only one potential major complication reported. In a different corner of small-animal orthopedics, a recent ex vivo Veterinary Surgery study comparing arthroscopy-assisted and fluoroscopy-assisted minimally invasive plate osteosynthesis for simple transverse acetabular fractures in dogs reached a similar practical theme: both approaches were feasible and produced anatomic or near-anatomic reductions, but minor superficial cartilage damage was common and sciatic nerve injury occurred once in each group. (pubmed.ncbi.nlm.nih.gov)
In the new paper, Brónach McClean, Turlough P. McNally, Antonio Pozzi, Richard Evans, and Laura C. Cuddy evaluated 32 paired canine cadaver pelvic limbs randomized to one of four techniques: lateral intercondylar notch, infrapatellar, suprapatellar, or proximal lateral parapatellar pouch. Before testing, the authors surveyed 40 surgeons and found the lateral intercondylar notch technique was the most commonly used, reported by 87.5% of respondents. All four approaches achieved successful joint access in 8 of 8 limbs, but the infrapatellar and suprapatellar methods required more needle repositioning than the lateral intercondylar notch and pouch techniques. (pubmed.ncbi.nlm.nih.gov)
The main differentiator was safety at the cartilage surface. The lateral intercondylar notch and suprapatellar techniques caused no iatrogenic cartilage injury in this cadaver model. The infrapatellar technique caused injury in 75% of limbs, and more than half of those lesions were larger than 10 mm² and located on weightbearing cartilage. The pouch technique also produced cartilage injury, though those lesions were confined to non-weightbearing cartilage. The authors concluded that the suprapatellar approach “may be a safer alternative” to established techniques and said it warrants further clinical investigation. (pubmed.ncbi.nlm.nih.gov)
That emphasis on tissue-level safety is echoed by the acetabular fracture repair study. In that ex vivo comparison, 10 canine cadavers weighing more than 20 kg underwent standardized simple transverse acetabular fracture creation, with pelvic CT images mirrored and 3D-printed to precontour 2.7-mm locking compression plates. Arthroscopy-assisted and fluoroscopy-assisted minimally invasive repairs were both completed successfully in all 20 acetabula, with no significant difference in procedure time or incision length. Mean fracture gaps and step defects were under 1 mm in both groups, and arthroscopy-assisted repair showed slightly less medio-lateral displacement than fluoroscopy-assisted repair. But necropsy still identified one sciatic nerve injury in each group, and minor superficial cartilage damage was common. The authors judged arthroscopy-assisted MIPO feasible, while cautioning that further studies and clinical experience are needed before it can be recommended as an alternative to open approaches. That is a different procedure and joint, but it reinforces the same broader message: minimally invasive success metrics can look strong even when collateral tissue effects remain relevant.
No outside expert commentary specific to this paper was readily available in the sources reviewed, but the findings align with broader concerns already present in the joint injection literature. The Cornell-authored review in Veterinary Clinics of North America: Small Animal Practice notes that ultrasound guidance may reduce periprocedural discomfort and iatrogenic cartilage damage, and that removing a small amount of synovial fluid before injection can help confirm placement and accommodate injectate volume. That context matters because this new study suggests some injury risk may be built into the landmark approach itself, even before considering image guidance or injectate choice. (pubmed.ncbi.nlm.nih.gov)
Why it matters: For veterinarians performing stifle taps or injections, the paper is a reminder that technical success and tissue safety aren’t the same endpoint. If a method reliably enters the joint but crosses or contacts clinically important cartilage, that tradeoff may matter most in dogs already dealing with cruciate disease, osteoarthritis, or repeat intra-articular therapies. The acetabular fracture study adds a useful parallel from another minimally invasive orthopedic procedure: even when reduction quality is excellent and feasibility is high, cartilage and nearby soft tissues can still be affected. The findings don’t prove the same injury pattern occurs in live patients, but they do provide a reason to revisit training, procedural protocols, and how clinicians weigh familiarity against tissue preservation. They may also support broader use of approaches that prioritize avoidance of weightbearing cartilage, especially when repeated access is expected. (pubmed.ncbi.nlm.nih.gov)
The study also offers a useful nuance for conversations with pet parents. Existing clinical data suggest therapeutic joint injections in dogs are generally safe overall, which should reassure practices already using them appropriately. But this ex vivo work indicates that the specific route into the stifle could still influence procedural risk in ways that aren’t obvious from outcome tracking alone, particularly if transient post-procedure soreness is the only routinely captured short-term signal. Seen alongside other minimally invasive orthopedic work showing that minor cartilage damage can occur despite good procedural endpoints, it supports a more refined discussion of risk than “accurate” versus “inaccurate” alone. (pubmed.ncbi.nlm.nih.gov)
What to watch: The key next step is clinical follow-up in live dogs to determine whether the suprapatellar approach remains practical and safer under real-world conditions, and whether it changes pain, complication rates, or clinician ease of use enough to shift standard practice. Given the paper’s publication timeline — e-published November 30, 2025, and appearing in the February 2026 issue of Veterinary Surgery — this is likely the stage where conference discussion, technique adoption, and prospective clinical studies begin. More broadly, the parallel acetabular fracture data suggest the field is moving toward more granular evaluation of minimally invasive procedures, with postprocedure imaging and necropsy-style assessment helping reveal harms that simple feasibility measures can miss. (pubmed.ncbi.nlm.nih.gov)