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Study: Most candidates for high tibial osteotomy have excessive lateral pressure syndrome

According to a recently published study, most patients who were candidates for high tibial osteotomy had excessive lateral pressure syndrome in the patellofemoral joint. However, researchers found no risk factors that correlated with the presence of excessive lateral pressure syndrome.

Researchers identified 150 patients who were candidates for high tibial osteotomy. Investigators defined excessive lateral pressure syndrome as grade 3 uptake on single-photon emission CT at the patellofemoral joint. Multivariate regression was used to determine risk factors associated with excessive lateral pressure syndrome.

Investigators found an increased uptake on the lateral side of the patellofemoral joint in 120 knees. Of these knees, 34 knees had a grade 3 uptake. According to researchers, this demonstrated a presence of excessive lateral pressure syndrome. There was no single factor that significantly correlated with the presence of excessive lateral pressure syndrome, they wrote. – by Monica Jaramillo

Disclosures: The researchers report no relevant financial disclosures.

According to a recently published study, most patients who were candidates for high tibial osteotomy had excessive lateral pressure syndrome in the patellofemoral joint. However, researchers found no risk factors that correlated with the presence of excessive lateral pressure syndrome.

Researchers identified 150 patients who were candidates for high tibial osteotomy. Investigators defined excessive lateral pressure syndrome as grade 3 uptake on single-photon emission CT at the patellofemoral joint. Multivariate regression was used to determine risk factors associated with excessive lateral pressure syndrome.

Investigators found an increased uptake on the lateral side of the patellofemoral joint in 120 knees. Of these knees, 34 knees had a grade 3 uptake. According to researchers, this demonstrated a presence of excessive lateral pressure syndrome. There was no single factor that significantly correlated with the presence of excessive lateral pressure syndrome, they wrote. – by Monica Jaramillo

Disclosures: The researchers report no relevant financial disclosures.

    Perspective
    Jason Koh

    Jason Koh

    Unanticipated effects from surgery can be a cause of poor outcomes but if candidates are at risk can be identified, treatment could be tailored to improve results. Jeong and colleagues’ recent article “Prevalence of excessive lateral pressure syndrome in varus osteoarthritic candidates for high tibial osteotomy” used an innovative imaging modality, SPECT–CT, to identify patellofemoral pathology in 216 knees that were potential candidates for high tibial osteotomy (HTO). S

    PECT-CT combines a 3-D nuclear medicine scan with a CT scan, resulting in the precise localization of small changes in bone metabolism. In this case, increased lateral patellofemoral uptake indicative of stress and excessive lateral pressure syndrome (ELPS) was detected in 56% of the knees, suggesting that there was concomitant patellofemoral pathology the majority of the time. No identifiable risk factors for ELPS were found.

    The primary weakness of this study is a lack of clinical correlation: It is unknown if these knees developed more PF symptoms after HTO surgery. Practically, the take-home message is that SPECT-CT may be a useful modality to identify patients at risk after opening wedge HTO, which can create patella baja and lateralize the tuberosity. 

    • Jason Koh, MD, MBA
    • Mark R. Neaman Family Chair of Orthopaedic Surgery
      University HealthSystem
      Director, NorthShore Orthopaedic Institute
      Evanston, Illinois
      Clinical professor, University of Chicago Pritzker School of Medicine
      Adjunct professor, Northwestern University McCormick School of Engineering

    Disclosures: Koh reports no relevant financial disclosures.

    Perspective
    Jack Farr

    Jack Farr

    Andreas Gomoll

    We all strive to satisfy our patients and precise surgical indications are key to achieving this goal. For medial osteoarthritis, treatment options include HTO and partial and total knee arthroplasty. Those patients who also have patellofemoral (PF) pain and arthritis add additional complexity when making the final decision. Regardless of the treatment, however, some patients will experience persistent anterior knee pain, even in patients who undergo TKA and receive patella resurfacing. Thus, any preoperative screening that would identify patients at-risk for postoperative anterior knee pain is valuable. 

    Jeong and colleagues published a retrospective study of excessive lateral compression syndrome (ELCS) in medial OA patients. They utilize a potentially useful screening tool to optimize indications and thus postoperative outcomes. Scott Dye previously demonstrated that SPECT CT/bone scan can detect bone metabolism changes earlier than MRI (noting that SPECT is much less utilized and available than MRI in the United States). In the current study utilizing SPECT to evaluate patients with medial OA for ELCS, Jeong and colleagues identified that more than half of patients had increased lateral patellofemoral uptake, and 16% had evidence of established ELCS. However, it must be kept in mind that this was an imaging study without clinical correlation, yet it leads the way for potential future studies that could correlate outcomes of HTO with the presence of ELCS.

    The first step in solving any problem is identifying there is a problem. In orthopedics, and life, most problems are multifactorial. While Jeong and colleagues did not identify specific risk factors associated with ELCS, they did suggest treatments to address it during HTO through lateral release  or tibial tubercle osteotomy. In regard to lateral release, in vitro cadaver studies have not demonstrated “unloading” of the patellofemoral compartment. On the other hand, medial tibial tuberosity transfer may decrease lateral patellofemoral loads as shown by Fulkerson and others.

    As a cautionary note, the majority of varus knees with medial OA have been shown to have medial rather than lateral patellofemoral chondrosis. This medial patellofemoral OA is “unloaded” with the valgus realignment of HTO and unicondylar knee arthroplasty by increasing the lateral patellofemoral force vector through lateralization of the tubercle. In a large series of Oxford UKAs, Beard and colleagues reported that patellofemoral OA did not influence the outcomes of medial UKA. In summary, Jeong and colleagues point to one additional factor potentially influencing post-HTO patellofemoral pain that desires clinical scrutiny and further study. 

    References:

    Beard DJ, et al. J Bone Joint Surg. 2007;doi:10.1302/0301-620X.89B12.19259.

    Beck PR, et al. Am J Sports Med. 2005;doi:10.1177/0363546505278300.

    Dye SF, et al. Orthop Clin North Am. 1986;17:249-262.

    Elahi S, et a. Arthritis Rheum. 2000;doi:10.1002/1529-0131(200008)43%3A8<1874%3A%3AID-ANR25>3.0.CO; 2-2.

    Fulkerson JP, et al. Am J Sports Med. 1990;18:490-497.

    Huberti HH, et al. J Orthop Res. 1988;6:499-508.

    Lewallen DG, et al. J Orthop Res. 1990;8:856-862.

    Ostermeier S, et al. Knee Surg Sports Traumatol Arthrosc. 2007;doiI:10.1007/s00167-006-0261-0.

    Ramappa AJ, et al. Am J Sports Med. 2006;doi:10.1177/0363546505283460.

    • Jack Farr, MD
    • OrthoIndy Knee Preservation and Cartilage Restoration Center
      Indianapolis

      Andreas Gomoll, MD
      Hospital for Special Surgery
      New York

    Disclosures: Farr and Gomoll report no relevant financial disclosures.

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