Humeral bone loss is commonly encountered during revision shoulder arthroplasty and anticipating humeral bone defects can help the revision surgeon make appropriate plans to achieve adequate fixation and stability. No validated classification system exists to characterize humeral bone loss in the setting of revision shoulder arthroplasty.
The purposes of this study were (1) to create a classification system for humeral bone loss in revision shoulder arthroplasty; (2) to determine the classification system’s reliability; and (3) to determine whether humeral bone loss type is associated with intraoperative humeral-related reconstruction characteristics.
This was a comparative retrospective radiographic study. First, six surgeons from five centers collaborated to create a classification by consensus. Second, two surgeons from two other centers who had fellowship training in shoulder and elbow surgery, who were blinded to each other’s grades and all patient details other than plain radiographs, and who were not involved in creation of the system, classified true AP, AP, and lateral (axillary and/or scapular-Y) radiographs from 108 revision (413 radiographs) from one center that were performed between November 15, 2006, and January 4, 2018. Interobserver reliability was calculated by comparing those two reviews and determining Cohen’s κ. In addition, one reviewer repeated his assessments twice, 4 months apart, to determine intraobserver reliability using Cohen’s κ. Third, we performed a retrospective chart study of these same revisions to determine intraoperative humeral-related reconstruction characteristics such as the use of greater tuberosity fixation, stem length, humeral bone grafting, and the use of proximal humeral replacement or total humeral replacement; at the center where these revisions were performed during that timespan, no attempt to classify bone loss was made. During that period, the general indications for greater tuberosity fixation included the absence of a stable osseous connection between the greater tuberosity and the shaft of the humerus with a tuberosity amendable to repair; the general indications for use of longer stems were inability to obtain a minimum of two cortical widths of overlap between the implant and the humeral diaphysis and/or loss of the greater tuberosity; and the general indications for proximal and total humeral replacement were bone loss that was felt to be too severe to allow reconstruction with allograft.
The classification system consists of three types of humeral bone loss: Type 1 is loss of the epiphysis with subtypes for loss of the calcar and loss of the greater tuberosity; Type 2 is loss of the metadiaphysis above the deltoid attachment with a subtype for cortical thinning; and Type 3 is bone loss extending below the deltoid attachment with a subtype for cortical thinning. We studied 108 revisions: 38 (35%) without bone loss, 34 (31%) Type 1, 27 (25%) Type 2, and nine (8%) Type 3. For reliability, interrater κ was 0.545 and in 71% (77 of 108) of revisions, the two raters agreed on a numeric type. Intrarater κ was 0.615 and in 77% (83 of 108) of revisions, the rater agreed with himself as to the numeric type. Stem length increased with class type (Type 1 median [range] 130 [70-210], Type 2 150 [70-210], Type 3 190 [70-240], p = 0.005). Most greater tuberosity fixation for intraoperative fracture was in Types 1 and 2 (13 of 18 compared with the five of 18 of greater tuberosity fixation that was within Types 0 and 3, p = 0.043). Most bone grafting was in Types 2 and 3 (eight of 13 compared with five of 13 of bone grafting was in Types 0 and 1, p = 0.044). Most proximal humeral and total humeral replacements were in Type 3 (three of four compared with one of four, p < 0.001).
We developed the Proximal Humeral Arthroplasty Revision Osseous inSufficiency (PHAROS) system, which has adequate, if imperfect, reliability to classify humeral bone loss in the setting of revision shoulder arthroplasty. This classification system may be useful to anticipate the complexity of humeral reconstruction. Further validation incorporating advanced imaging and further evaluators will be necessary.
Level III, diagnostic study.
P. N. Chalmers, R. Z. Tashjian, Department of Orthopaedic Surgery, University of Utah, Salt Lake City, UT, USA
A. A. Romeo, Department of Orthopaedic Surgery, Rothman Institute, New York, NY, USA
G. P. Nicholson, Department of Orthopaedic Surgery, Rush University Medical Center, Chicago, IL, USA
P. Boileau, Department of Orthopaedic Surgery, CHU-Nice, Nice, France
J. D. Keener, Department of Orthopaedic Surgery, Washington University, St Louis, MO, USA
J. M. Gregory, Department of Orthopaedic Surgery, University of Texas at Houston, Houston, TX, USA
D. H. Salazar, Department of Orthopaedic Surgery, Loyola University, Chicago, IL, USA
P. N. Chalmers, Department of Orthopaedic Surgery, 590 Wakara Way, Salt Lake City, UT 84108, USA, email: email@example.com
One of the authors certifies that he (PNC) has received payments, during the study period, of an amount of less than USD 10,000 from DePuy (New Brunswick, NJ, USA). One of the authors certifies that he (AAR) has received payments, during the study period, of an amount greater than USD 1,000,000 from Arthrex (Naples, FL, USA) and of amounts less than USD 10,000 from the American Shoulder and Elbow Surgeons (Chicago, IL, USA), Atreon (Columbus, OH, USA, Orthopedics (Slack Inc, Thorofare, NJ, USA), Orthopedics Today (Slack Inc), SAGE Publishing (Newbury Park, CA, USA), Wolters Kluwer Health Publishing (Philadelphia, PA, USA), Aesculap/B. Braun (Bethlehem, PA, USA), Histogenics (Waltham, MA, USA), Medipost (Rockville, MD, USA), NuTech (Birmingham, AL, USA), OrthoSpace (Caesarea, Israel), Smith & Nephew (Memphis, TN, USA), Zimmer (Warsaw, IN, USA), Saunders (Philadelphia, PA, USA), the Arthroscopy Association of North American (Chicago, IL, USA), and Major League Baseball (New York, NY, USA). One of the authors certifies that he (GPN) has received payments, during the study period, of an amount less than USD 10,000 from American Shoulder and Elbow Surgeons (Chicago IL, USA), Arthrosurface (Franklin, MA, USA), Innomed (Savannah, GA, USA), and Wright Medical (Memphis, TN, USA). One of the authors certifies that he (PB) has received payments, during the study period, an amount of greater than USD 1,000,000 from Wright Medical and of amounts less than USD 10,000 from Smith & Nephew and CONMED Linvatec (Utica, NY, USA). One of the authors certifies that he (JDK) has received payments, during the study period, of an amount of USD 10,001 to 100,000 from Arthrex and of an amount less than 10,000 USD from Elite Orthopaedics (South El Monte, CA, USA) and Zimmer. One of the authors (JMG) is a board or committee member for the American Academy of Orthopaedic Surgeons and serves as a paid consultant for Wright Medical. One of the authors certifies that he (RZT) has received payments, during the study period, of an amount less than 10,000 from Zimmer, DePuy, Conextions (Salt Lake City, UT, USA), INTRAFUSE (Salt Lake City, UT, USA), KATOR (Salt Lake City, UT, USA), Wright Medical, the Journal of Bone and Joint Surgeons (Needham, MA, USA), and the Journal of Orthopaedic Trauma (Tampa, FL, USA).
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Each author certifies that his institution approved the human protocol for this investigation and that all investigations were conducted in conformity with ethical principles of research.
This work was performed at the University of Utah, Salt Lake City, UT, USA.
Received August 31, 2018
Accepted November 09, 2018