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    PRACTICE PEARLS: Joint Preservation vs. Arthroplasty in Patients with Hip OA

    The last 10 years has seen rapidly increasing interest in hip preservation procedures, as documented in recent studies. [1]

    But not all patients with structural hip disease – known to predispose patients to osteoarthritis (OA) – are appropriate candidates for hip preservation surgery. The challenge, said Christopher L. Peters, MD, is to understand when hip preservation surgery is the right choice and when the joint is too arthritic for preservation and total hip arthroplasty (THA) must be considered.

    At the ICJR South/RLO Course, Dr. Peters, from the University of Utah in Salt Lake City, reviewed conditions in which hip preservation procedures are applicable, as well as the indications and contraindications for these procedures.

    He also noted that although many surgeons hesitate to perform THA in patients under age 30, the procedure is very successful. Cementless fixation is durable, and most failures in the literature are due to failure of the bearing surfaces. For the patient, the clinical improvement is substantial.

    Femoroacetabular Impingement

    Hyaline cartilage delamination is the initiating event in the development of OA in most young patients with femoroacetabular impingment (FAI). Dr. Peters said that the following factors are associated with failure of joint preservation procedures in these patients:

    • Joint space narrowing < 2mm [2]
    • Tonnis Grade > 2 OA
    • Age > 40
    • Size of cam lesion (> 65° alpha angle) [3]
    • Residual structural deformity [4]
    • Chondrolabral treatment (labral excision)

    The Tonnis classification is most commonly used to classify OA in patients with dysplasia, but Dr. Peters applies it across the spectrum of conditions appropriate for hip preservation procedures. He reviewed this classification system, noting that long-term outcomes of hip preservation procedures are much better for patients with Tonnis Grades 0 and 1.

    Dysplasia

    The pathomechanics of dysplasia are different from those of FAI, Dr. Peters said. Dysplasia is pathoanatomy, characterized by decreased acetabular coverage and occasionally decreased acetabular congruency. This creates a condition of overload at the acetabular rim, causing failure at the chondro-labral junction, which, in turn, leads to OA in the untreated patient.

    Current treatment options for hip dysplasia are periacetabular osteotomy (PAO) and total hip arthroplasty (THA). When deciding which treatment is more appropriate, Dr. Peters considers the following factors:

    Factors favoring PAO

    • Young patient < 35 to 40 years old
    • Low BMI
    • Congruent hip joint
    • Tonnis Grade 0 to 1 OA
    • Maintained range of motion
    • Radiographic dysplasia: lateral center-edge angle – LCEA < 20° to 25°

    Factors favoring THA

    • Age > 35 to 40 years
    • Tonnis Grade 2 to 3 OA
    • Non-congruent joint
    • Subchondral cyst formation
    • MRI / dGEMERIC acetabular chondral damage

    Dr. Peters cautioned that several studies now show rapid progression of OA in patients with dysplasia treated primarily with removal of the labrum. [4,5,6]

    Summary

    • Hip preservation is effective in patients < 40 years old with Tonnis Grade 0 to 1 OA.
    • Patient selection is critical!
    • THA is an excellent option for young patients who are not candidates for hip preservation procedures.
    • Future challenges include understanding the role of patient-specific arthrokinematics in OA progression.

    Disclosures

    Dr. Peters has no disclosures relevant to this article.

    References

    1. Montgomery SR, Ngo SS, Hobson T. Trends and demographics in hip arthroscopy in the United States. Arthroscopy.2013;29:661-665
    2. Philippon MJ, Briggs KK, Carlisle JC, Patterson DC. Joint space predicts THA after hip arthroscopy in patients 50 years and older. CORR 2013 Aug;471(8):2492-6.
    3. Beaulé PE, Hynes K, Parker G, Kemp KA. Can the alpha angle assessment of cam impingement predict acetabular cartilage delamination? CORR 2012 Dec;470(12):3361-7
    4. Bogunovic L, Gottlieb M, Pashos G, Baca G, Clohisy JC. Why do hip arthroscopy procedures fail? CORR 2013 Aug;471(8):2523-9.
    5. Parvizi J, Bican O, Bender B, et al. Arthroscopy for labral tears in patients with developmental dysplasia of the hip: a cautionary note. J Arthroplasty. 2009 Sep;24(6 Suppl):110-3.
    6. Matsuda DK1, Khatod M. Rapidly progressive osteoarthritis after arthroscopic labral repair in patients with hip dysplasia. Arthroscopy. 2012 Nov;28(11):1738-43.