Chronic Knee Pain is the Paramount Presentation in Patients with Nail-Patella Syndrome
Authors: Kaissi Ali Al 
Published: January 2023

Background: Arthralgia in connection with patellar instability have been studied thoroughly in a number of pediatric and adult patients. Small and dysplastic patellae accompanied by hypoplasia of the lateral femoral condyle may results in recurrent subluxation or dislocation of the patellae, knee discomfort and pain. We aimed to detect the underlying etiology of every single patient.

Patients and Methods: A total of seven children presented with long term painful knee joints have been refered from the departments of rheumatology. We added adult female patient of a-35-years-old. She was a chronic client of rheumatology clinics since her postadulthood. In addition to her early life knee pain. Recently she experienced additional chronic pain of the groin (located at the posterior buttocks). All our patients showed episodes of knee pain with variable intensity as a constant complaint and all received antirheumatic treatments for years despite the negative results of the implemented tests. In order to commence the diagnostic process, clinical and radiological phenotypic characterization were the main core of our stratregy followed by molecular genetic confirmation.

Results: Seven unrelated children (aged from 8-17 years old) were consistent with the diagnosis of Nail- Patella syndrome. The adult female patient of a-35-years-old- manifested patellar instability since her early childhood. Her clinical phenotype was totally compatible with the diagnosis of Nail-Patella syndrome. Surprisingly, the clinical examination of the female patient and the standing AP pelvis radiograph revealed massive encroachment of the medial aspect of the femoral neck and the lesser trochanters onto the ischium. The latter resulted in the diagnosis of Ischiofemoral Impingement (IFI) syndrome. Her genetic tests showed heterozygous mutation in the LIM-homeodomain protein LMX1B on chromosome 9q33.

Conclusion: Arthralgia associated with abnormal gait (mostly antalgic gait and waddling gait) was the paramount clinical presentation in all our patients. Dysplasia of the nails and patellar instability were the characteristic clinical findings in our patients with the definite diagnosis of osteo-onychodysplasia syndrome. We approached to the diagnosis from the first session of clinical examination. Interestingly, the constant groin pain in the adult female patient which has been totally overlooked by other instutions, were in favor of the diagnosis of Ischiofemoral Impingement (IFI) syndrome. As well as the existing abnormality of the elbows associated with defective pronation and supination as due to impingement of the olecranon. The task of establishing the diagnostic process in complex clinical conditions is the most challenging. Sadly speaking, none of the aforemnetioned dignostic criteria attracted the attention of dozens of clinicians. Admistering medications to overcome knee pain through dozens of useless laboratory tests were the main false issue. Clinicians who are actively involved in clinical diagnosis with minimal dependency on laboratory aid are generally at the forefront of their medical fields.