In The Name of In The Name of GodGod

Comparison between the Comparison between the different morphologic types of different morphologic types of

the patella in patients with the patella in patients with chondromalacia and normal chondromalacia and normal

personspersons

Kamran Azma MDKamran Azma MD11, ,

Neda Entezari MDNeda Entezari MD22

1. Department of Physic medicine and rehabilitation 501 hospital, Army University of Medical Sciences, Tehran, Iran.

2. Immunology, Asthma and Allergy Research Institute, Tehran, Iran

ChondromalaciaChondromalacia

Patellofemoral pain (PFP) is one of the Patellofemoral pain (PFP) is one of the most common disorders of the knee. most common disorders of the knee. Patients with Patients with patellofemoral pain syndrome patellofemoral pain syndrome (chondromalacia(chondromalacia patella) typically present patella) typically present with a vague historywith a vague history of mild to moderate of mild to moderate anterior knee pain thatanterior knee pain that usually occurs after usually occurs after prolonged periods of sittingprolonged periods of sitting (the so-called (the so-called “theater sign”).“theater sign”).

The term "chondromalacia" was first used The term "chondromalacia" was first used by Aleman in 1928. by Aleman in 1928.

Chondromalacia PatellaChondromalacia Patella

Softening/deterioration Softening/deterioration of articular cartilage of articular cartilage post pat post pat

StagesStages1.1. Swelling and softeningSwelling and softening

2.2. Fissuring Fissuring

3.3. Deformation Deformation (fragmentation)(fragmentation)

Pain with walking, running, ascending and Pain with walking, running, ascending and descending stairs, and squattingdescending stairs, and squatting

Grating or grinding with knee flexion or Grating or grinding with knee flexion or extensionextension

Pain at inferior border during palpationPain at inferior border during palpation

ManagementManagement• Conservative measuresConservative measures• Surgical possibilitiesSurgical possibilities

Signs and symptomsSigns and symptoms

EtiologyEtiology TheThe etiology of chondromalacia patella is unclear. etiology of chondromalacia patella is unclear. It has beenIt has been attributed to predisposing factors such attributed to predisposing factors such as patellar malalignmentas patellar malalignment and trauma, but many and trauma, but many cases are idiopathic. cases are idiopathic. CP most often affects adolescents and young CP most often affects adolescents and young adults and may be primary and idiopathic or occur adults and may be primary and idiopathic or occur subsequent to patellar shape.subsequent to patellar shape.

DiagnosisDiagnosis The clinical diagnosisThe clinical diagnosis may be confirmed at may be confirmed at

arthroscopy when changes inarthroscopy when changes in cartilage can be cartilage can be directly visualized. However, it is not alwaysdirectly visualized. However, it is not always thought necessary to carry out an invasive thought necessary to carry out an invasive procedure such asprocedure such as arthroscopy to diagnose an arthroscopy to diagnose an often benign and self limitingoften benign and self limiting condition.condition.

PatellaPatella The knee joint is the The knee joint is the

largest and most largest and most complicated joint and with complicated joint and with its three degrees of its three degrees of freedom, is one of the freedom, is one of the most functional units in the most functional units in the body. body.

The standard radiographic The standard radiographic series for assessment of series for assessment of patellofemoral patellofemoral relationships includes an relationships includes an anteroposterior, a lateral anteroposterior, a lateral and an axial view.and an axial view.

Wiberg described three patellar types based on morphology on Wiberg described three patellar types based on morphology on the axial view (Fig. 1).the axial view (Fig. 1).

Figure 1Figure 1 Anatomic variations in patellar shape. Type 1 patella has concave medial Anatomic variations in patellar shape. Type 1 patella has concave medial and lateral facets approximately equal in size. Type 2 also has concave facets, and lateral facets approximately equal in size. Type 2 also has concave facets, but the medial facet is smaller than the lateral. Type 3 has a small convex medial but the medial facet is smaller than the lateral. Type 3 has a small convex medial facet.facet.

Grelsamer described a "morphology ratio" Grelsamer described a "morphology ratio" relating the overall patellar length to the relating the overall patellar length to the patellar articular length.patellar articular length.

Grelsamer described three types of patella Grelsamer described three types of patella based on morphology ratio on the lateral view based on morphology ratio on the lateral view (with 30 flexion).(with 30 flexion).

5.12.1: b

aTypeI

5.1: b

aTypeII

2.1: b

aTypeIII

b

a

lengtharticularpatellar

lengthpatellaroverallRatioymorpho log

AimAim

The purpose of this case control study is The purpose of this case control study is comparison between the different morphologic comparison between the different morphologic types of the patella (Wiberg classification and types of the patella (Wiberg classification and morphology Ratio) in patients with morphology Ratio) in patients with chondromalacia and normal persons.chondromalacia and normal persons.

MethodMethodThirty patients(20 males, 10 females) with a Thirty patients(20 males, 10 females) with a

clinical diagnosis of chondromalacia patella who clinical diagnosis of chondromalacia patella who attended either the Physic medicine and attended either the Physic medicine and

rehabilitation department in Army hospital were rehabilitation department in Army hospital were selected for study. selected for study.

Medial and lateral facets were calculated on Medial and lateral facets were calculated on patellar knee view. patellar knee view.

Also patellar articular length and overall patellar Also patellar articular length and overall patellar length were calculated in knee joint in lateral length were calculated in knee joint in lateral

view 30 degrees flexion. view 30 degrees flexion. The results were compared to values obtained The results were compared to values obtained

from 30 limbs in 30 healthy volunteers. from 30 limbs in 30 healthy volunteers.

Figure 2Figure 2 Patella types (morphology ratio) in patients with Patella types (morphology ratio) in patients with chondromalacia patella and healthy subjects.chondromalacia patella and healthy subjects.

In Morphology ratio classification, 40% of normal In Morphology ratio classification, 40% of normal persons had patella type II while 13% of patients had this persons had patella type II while 13% of patients had this type (p=0.02). Also none of normal persons had patella type (p=0.02). Also none of normal persons had patella type III while 13% of patients had this type (p=0.03).type III while 13% of patients had this type (p=0.03).

60

40

0

74

13 13

0

20

40

60

80

I (Morphology ratio classification) II III

Healthy Subjects

Chondromalacia patients

ResultsResults

In Wiberg classification, 57% of normal persons had patella In Wiberg classification, 57% of normal persons had patella type I while 17% of patients with chondromolacia had this type I while 17% of patients with chondromolacia had this type (p=0.01). Also 43% of normal persons had patella type type (p=0.01). Also 43% of normal persons had patella type II while 83% of patients had this type (p= 0.01).II while 83% of patients had this type (p= 0.01).

Figure 3Figure 3 Patella types (Wiberg classification) in patients with Patella types (Wiberg classification) in patients with chondromalacia patella and healthy subjects.chondromalacia patella and healthy subjects.

57

43

0

17

83

00

20

40

60

80

100

I (Wiberg classification) II III

Healthy Subjects

Chondromalacia Patients

DiscussionDiscussion

Wiberg believed that type III patella was Wiberg believed that type III patella was associated with severe chondromalacia associated with severe chondromalacia and that the stress on the medial facets and that the stress on the medial facets was increased by there being only a small was increased by there being only a small convex area of contact with the condyles. convex area of contact with the condyles. In our study we have not any patients with In our study we have not any patients with patella type III, but we believed that type II patella type III, but we believed that type II patella was also associated with patella was also associated with chondromalacia because in this type, the chondromalacia because in this type, the medial facet is smaller than the lateral.medial facet is smaller than the lateral.

DiscussionDiscussion

We think that as the ratio of overall patellar We think that as the ratio of overall patellar length to patellar articular length increase, length to patellar articular length increase,

the probability of chondromalacia declines.the probability of chondromalacia declines.A variety of sports commonly lead to A variety of sports commonly lead to

chondromoalacia patella due to unusual chondromoalacia patella due to unusual compressive forces. Therefore young compressive forces. Therefore young

population specially athletes should pay population specially athletes should pay attention to their patellar shapes in order attention to their patellar shapes in order

to choose their favorite sports.to choose their favorite sports.