This document discusses the diagnosis and treatment of patellofemoral instability. It notes that instability can be traumatic or atraumatic, with recurrent dislocations having a 50% chance of further episodes. Non-operative treatments include physical therapy targeting muscles like the VMO. Surgical options include soft tissue procedures like medial repair or MPFL reconstruction, and bone procedures like trochleoplasty, tubercle osteotomies, or distal realignment. MPFL reconstruction is commonly used for incompetent medial structures but studies on techniques are limited. Treatment should be customized based on the underlying anatomical abnormalities or soft tissue insufficiencies identified in each individual case.

1. Gonzalo Samitier MD

2. DIAGNOSIS
 LUX or SUBLUX PATELLOFEMORAL
 PAIN wo INSTABILITY

3. DIAGNOSIS
1st EPISODE (15-44% recurrence Hawkins RJ
AJSM 1986)
 TRAUMATIC (20% recurrence Cash and
Hughston AJSM 1988 )
 ATRAUMATIC (43% recurrence Cash and
Hughston AJSM 1988)
 COMBINATION
RECURRENT (50% recurrence chance if
second episode Fithian AJSM 2004)
Surgical treatment??
Surgical treatment

4. ETIOLOGY
- Patella alta
- Throclear dysplasia
- Alignment
- Rotational (Torsion). Femoral and tibial
- Genu Valgum
- Q angle
- Hyperlaxity
- Muscular weakness (VMO)
- Tight lateral structures
- Traumatic MPFL insufficiency
- Iatrogenic

5. Who tends to recurr (Palmu JBJS Am
2008)
LAXITY
- Young (up to 71%)
- Female
- Family history
- Bilateral
- Atraumatic dislocations
ANATOMIC ABNORMALITIES
- Patella alta
- Trochlear dysplasia
- TT TG distance
- Q angle
- Quad dysfunction
Palmu JBJS 2008, Fithian AJSM 2004, Garth AJSM
1996, Dejour KSSTA 1994, Larsen CORR 1982

6. IMPORTANT ANTOMY
 TROCHLEAR GROOVE (primary bony stabilizer)
 MEDIAL PATELLOFEMORAL
LIGAMENT (primary soft tissue stabilizer) 60% lateral
restraint (Desio AJSM 1998)
 QUADRICEPS (VMO) (Dynamic stabilizer)

7. PHYSICAL EXAM
- Gait
- Standing alignment
- Q angle
- J sign (indicates patela alta)
- Laxity (N less than 50% or 2 Q Carson et al Clin Orthop
1984)
- Prone rotational alignment (femoral anteversion
and tibial torsion N<20º)
Others: patelar tilt, aprehension test, grinding,
ROM and tracking

8. IMAGING
- Patella alta
- Patellar tilt
- Patelar morphology
- Trochlear dysplasia

9. IMAGING
- Patella alta
- Patellar tilt
- Patelar morphology
- Trochlear dysplasia
(Dejour et al. Sport Med Arthroscopy
2007)

10. SECONDARY IMAGING
CT Scan
TT-TG distance
(Tibial tubercle -
trochlear groove >20mm
abnormal
Hip to ankle long
standing film
CT Torsional profile

11.  MRI
 Ruptured MPFL
 Osteochondral
fragments
 Bone bruise - lateral
femoral condyle/medial
patellar facet
SECONDARY IMAGING
Approximately 50% to 80% of injured medial pa- tellofemoral ligaments
are disrupted at their femoral origin

12. TREATMENT
 CONS
 SURGICAL

13. Non-operative Treatment
 PT
 Stretching
 Strengthening (esp VMO and Gluteal)
 Closed chain/WB (Stensdotter et al. Escamilla et al.)
 Weight loss (reduce PF loads)
 Inmobilization vs Bracing (Palumbo)
Maenpaa and Lehto (AJSM 1997),

14. Operative Treatment
- Soft tissue procedures:
- Lateral release
- Medial repair
- Proximal realignment
- MPFL reconstruction
Bone Procedures
- Trochleoplasty
- Distal Femoral Osteotomies
- Distal realignment
- Rotational Osteotomies

15. Operative Treatment
- Soft tissue procedures:
- Lateral release
- Medial repair
- Proximal realignment
- MPFL reconstruction
Bone Procedures
- Trochleoplasty
- Distal Femoral Osteotomies
- Distal realignment
- Rotational Osteotomies

16. Lateral release
Not recommended to be done in isolation for instability
- Contribute to 10% of the restraining force to lateral translation
(Desio et al AJSM 1998)
- Results decline from initial 80% to 29%-74% satisfactory rating
at 4 years (LattermannC et al. Med Arthroscopy 2007)

17. Medial repair
- Used often in the acute setting. Open or
arthroscopic
- Doesn’t address tears of the femoral side
- Limitations: can cause over medialization and tilt
- Prospective Studies: No difference medial vs non
op treatment (Nikku Acta Orthop 2005, 1997, Palmu JBJS 2008,
Sillanpaa PJ AJSM 2008)
- Cases series showing acceptable results
(Ali S Arthroscopy 2007, SchottlePG Arthroscopy 2006, HallbruchtJL
Arthroscopy 2001, Ahmad CS AJSM 2000, Boring TH CORR 1978

19. MPFL Reconstruction
- Used for incopetent medial structures
- Goals: re-create MPFL anatomy
- Re-establish a stable checkrein 0-30º
- Concerns: overtightening, patella fracture
- Controversial (graft choice, graft fixation, graft positioning,
Graft tension, Dynamic reconstruction)
Systematic review Bucket C et al. AJSM
2009
14 studies including Level III/IV
Stability and Clinical Outcomes encouraging
but current studies are small

20. Donald C Fithian Dr., MD
Kaiser Permanente Med Ctr Ortho

21. Operative Treatment
- Soft tissue procedures:
- Lateral release
- Medial repair
- Proximal realignment
- MPFL reconstruction
Bone Procedures
- Trochleoplasty
- Distal Femoral Osteotomies
- Distal realignment
- Rotational Osteotomies

22. Trochleoplasty
 Elevating osteotomy of
lateral trochlear facet
 Concerns:
 Cartilage disruption
 Change in PF contact
pressures
 Rarely indicated because
of above

24. Fulkerson Procedure
(Anteromedial Tibial Tubercle AMZ
Transfer)
 Hallmark indication: Increased TT-TG distance
 Corrects Q angle by medializing tubercle
(~0.5-1cm)
 Used only when patella not tracking in center
of trochlea
 Tubercle move anterior (~1cm) as well to
unload PF joint and move point of contact
proximal throughout flexion (distal pole of
patella common source of pain)
 Re-attached with multiple screw fixation
 NWB 6-8 weeks

27. PATELLAR INSTABILITY
ALGORITHM
Severe Alignment Abnormalities
Genu Valgum
- Distal Femoral OT
- Guided Growth
Torsion >20º above normal
- Femoral rotational OT >35º
- Tibial rotational OT 40º
Increased TT-TG >20mm
Q Angle > 15-20º
Distal Re-Alignment
- If Alta then distalize
Incompetent Medial
restraint
MPFL Reconstruction
IF UNSUCCESSFUL, LOOK FOR ABNORMALITIES NOT INITIALLY APPRECIATED
BOTH?
NOYES

28. CONCLUSIONS
 There are multiple causes for Patellofemoral
instability
 Good evidence for the non-operative treatment of
an acute patellar dislocation, most of the current
surgical treatments for chronic patellar instability
are based on Level-IV evidence
 Customize your treatment based in the problem
 Be familiar with MPFL reconstruction technique
 Tubercle osteotomy should not be performed if
there is associated medial or proximal patellar
chondrosis
 Watch the alignment

29. Gracias …