The Effect of Proximal Lunate Morphology " Zapico Classification" on Kienböck's Disease

The Kienböck's disease (KD), even today, has many obscurities. Its etiologies as well as classifications are under constant change and debate, therefore we decided to define the effect of proximal lunate morphology on KD and its usefulness in evaluating the course of the disease.
The purpose of this study is to compare the 3 different morphologies of the proximal lunate as defined by Antuna-Zapico (A-Z) in KD patients with a control group of normal individuals, and also compare the morphologies in different aspects like ulnar variance (UV), radial inclination and radial volar tilt, lunate sizes in radiological views, males and females, symptom duration before seeking medical treatment, lunate fragmentation, and also Lichtman’s stages of the disease.
Unaffected wrist X-rays of 107 KD patients (71 male 36 female), 17 - 53 years old, since 2011 to 2016, compared with 100 age and sex matched normal individuals divided in 3 lunate morphologies “as Antuna-Zapico has proposed”; noticing also the wrist indexes and the disease stages according to Lichtman’s classification.
The prevalence of 3 different A-Z classification morphologies were; 18 (16.8%) Type1, 77 (72%) Type 2, and 12 (11.2%) Type 3 in the case group that wasn’t statistically different from the control group, with 15 (15%) Type 1, 73 (73%) Type 2, and 12 (12%) Type 3 (P = 0.9), even separately as male (P = 0.4) and females (P = 0.5). Case and controls were different in ulnar variance UV, (P = 0.001), however, different morphologies had a different UV inside the case group (P = 0.4). All 3 morphologies were seen in all different Lichtman’s stages with no correlation to the specific stage or morphology (P = 0.2). In the case group, no correlation was found between different morphologies and lunate width (P = 0.5), diameter (P = 0.4), radial tilt (P = 0.8), volar tilt (P = 0.8).
Proximal lunate morphology, as depicted by A-Z, has no effect on the course of the disease and doesn’t play any key role in the etiology. Its prevalence is the same as the general population.