Diagnosis, algorithm and definitive treatment for patellofemoral instability

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 …