Patella alta
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Search Strategy[edit | edit source]
The following databases have been used to find information about "Patella alta": Pubmed, Medscape, Google scholar, Pedro, Online database of the VUB
Words that have been used: Patella alta, Conservative treatment AND patella alta, Patella alta AND physical therapy, Patellar dislocation & Etiology
Definition/Description[edit | edit source]
Patella alta or high-riding patella refers to an abnormally high patella in relation to the femur. The patella sits high on the femur where the groove is very shallow. Here the sides of the femoral groove provide only a small barrier to keep the high-riding patella in place. A strong contraction of the quadriceps muscle can easily pull the patella over the edge and out of the groove, leading to a patellar dislocation. This condition has been associated clinically with patellofemoral dysfunction and is considered a predisposing factor for the development of patellofemoral pain (PFP). Patella alta is also characterized as instability of the Patella[1][2][3]
Clinically Relevant Anatomy[edit | edit source]
Patella_alta:_Clinically_relevant_anatomy
Etiology[edit | edit source]
Patella Alta can occur as the result of a sports injury, though the large majority of the time it is a congenital/developmental condition that is unrelated to trauma. Its pathophysiology is not completely clear, but it is hypothesized that one of the causes of Patella Alta, are abnormally long patellar tendons (>52 mm)[4][5]
Characteristics/Clinical Presentation[edit | edit source]
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Differential Diagnosis[edit | edit source]
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Diagnostic Procedures[edit | edit source]
For confirmation, a lateral X-Ray is made with the knee bent at 90 degrees. This will confirm the patella alta, by measuring its height[6]
Outcome Measures[edit | edit source]
Several methods are used to determine the presence of patella alta. Insall and Salvati were the first to describe a method of establishing patellar height on the basis of the ratio of the length of the patellar tendon to the diagonal length of the patella on lateral radiographs. Various techniques, including those by Blackburne and Peel, Caton et al., and de Carvalho et al., have since been developed in the attempt to classify patellar position. In the modified Insall-Salvati ratio, patellar bone length is replaced with patellar articular cartilage length. The Insall-Salvati index, however, is the most widely accepted method because of its lack of dependence on the degree of knee flexion and its established MRI criteria[7][8]
The Insall-Salvati ratio is the ratio of the patella tendon length to the length of the patella. This can be measured on a lateral knee xray or sagittal MRI. Ideally the knee is 30 degrees flexed[9]
The Blackburne-Peel ratio is used to assess patellar height, and determine presence of patella alta. A lateral radiograph of the knee with 30 degrees of flexion is obtained, and a horizontal line at the level of the tibial plateaux is drawn. Perpendicular to this line vertically and a measurement (B) made of the distance between the horizontal line and the inferior aspect of the patellar articular surface. A second measurement (A) is made along the patellar articular surface.[10]
• A/B is a measure of patellar height
Normal value = ratio of 0.8.
Patella alta = ratio >1.0
Examination[edit | edit source]
The patient sits on the edge of the examination table with the feet on the ground. The knees are bent at 90 degrees, and the thigh is horizontally positioned. The vertical position of the patella height is best observed from lateral. In Patella Alta it can be seen that the partially tilted patella protrudes above the level of the thigh. This is more remarkable In a unilateral Patella alta. A patella alta may be noticed during inspection thanks to a so-called Camel hump patella, the knee has two striking bulges. one is the tibial tuberosity, the other is the patella. The space, Distal to the patella and proximal to the fat body of Hoffa is characterized by a notch[11]
Medical Management
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Physical Therapy Management
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Manual gliding is performed to theoretically modify the resting height of the patella before knee extension, resulting in decreased pain in the knee. Correction of the positional fault of the patella by using tape, is a method to correct patellar alignment
Patients noted that they were having minimal difficulty with walking, Their average pain was reported to be a 1–2/10 on a VAS scale, and they noted decreased use of pain medication
Key Research[edit | edit source]
A study suggest that Patellar tendon tenodesis and tibial tubercle distalization result in normalization of patellar tendon length, a stable patellofemoral joint, and good long-term knee function in patients with patella alta. A perfect postoperative stability was found in 76.8% of patients[12]
Resources
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Clinical Bottom Line[edit | edit source]
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Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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- ↑ Ward SR, Powers CM; The influence of patella alta on patellofemoral joint stress during normal and fast walking; Clin Biomech (Bristol, Avon). 2004 Dec;19(10):1040-7 (B)
- ↑ Stefanik JJ et al ; Quadriceps Weakness, Patella Alta, and Structural Features of Patellofemoral Osteoarthritis; Arthritis Care Res (Hoboken). 2011 Oct;63(10):1391-7 (B)
- ↑ Syed A. Ali, Robert Helmer, Michael R. Terk; Patella Alta: Lack of Correlation Between Patellotrochlear Cartilage Congruence and Commonly Used Patellar Height Ratio; AJR November 2009 vol. 193 no. 5 1361-1366 (B)
- ↑ Florence Peterson Kendall et al.; Spieren: tests en functies, Bohn Stafleu van Loghum, Nederland, 469p (Level of evidence: D)
- ↑ Human kinetics Publisher. Clincal anatomy of the patellofemoral joint. International sportsmedicine journal. 2001. Level of evidence: (D)
- ↑ Bohn Stafleu van Loghum (Level of evidence: D)
- ↑ Ward SR, Terk MR, Powers CM.; Patella alta: association with patellofemoral alignment and changes in contact area during weight-bearing.; J Bone Joint Surg Am. 2007 (Level of evidence: B)
- ↑ Syed A. Ali, Robert Helmer and Michael R. Terk; Patella Alta: Lack of Correlation Between Patellotrochlear Cartilage Congruence and Commonly Used Patellar Height Ratios; AJR November 2009 vol. 193 no. 5 1361-1366. (Level of evidence: B)
- ↑ Insall J, Salvati E.; Patella position in the normal knee joint. Radiology 1971; 101:101–104fckLRBlackburne JS, Peel TE. A new method of measuring patellar height. J Bone Joint Surg Br 1977; 59:241–242 (Level of evidence: D
- ↑ Syed A. Ali, Robert Helmer, Michael R. Terk; Patella Alta: Lack of Correlation Between Patellotrochlear Cartilage Congruence and Commonly Used Patellar Height Ratio; AJR November 2009 vol. 193 no. 5 1361-1366 (Level of evidence: C)
- ↑ Bohn Stafleu van Loghum
- ↑ Patellar tendon tenodesis in association with tibial tubercle distalization for the treatment of episodic patellar dislocation with patella alta. Mayer C, Magnussen RA, Servien E, Demey G, Jacobi M, Neyret P, Lustig S. Department of Orthopedic Surgery, Hôpital de la Croix-Rousse, Centre Albert Trillat, Lyon, France (Level of evidence 4)
