Realignment Osteotomies of the Knee Bill Wiley ORV April 17, 2003

Evaluation Overall alignment Range of Motion Knee Stability Assessment of Leg Length

Indications Unicompartment Osteoarthritis Under 60 yoa Good ROM No Flexion Contracture Not Overweight Unloading for Meniscal/Chondral Grafting Relative for ACL or PLC deficient in Varus

Radiographs Full Length weight bearing AP 30 degree PA flex Lateral Sunrise

Classification of Varus Knees Noyes AJSM 2000 Primary Varus – tibiofemoral alignment due to loss of meniscal and articular cartilage (Bony) Double Varus – bony and separation of the lateral tibiofemoral compartment due to soft tissues stretching out Triple Varus – bony, soft tissue stretching, and chronic abnormalities resulting in recurvatum and external tibial rotation

Other Options to Consider UKA TKA

Conservative Measures Shoe wedges Unloader Braces

Templating Anatomic Axis – in line with the shaft of the femur and tibia (avg of 5 to 6 degrees valgus) Mechanical Axis – center of hip to center of ankle (normal is slightly in medial compartment) Mechanical Axis of Femur (MAF) – CH to CK Mechanical Axis of Tibia (MAT) – CK to CA Mechanical Axis Angle (MAA)– angle btwn MAF and MAT (avg person is minus 1 degree, ie 1 degree varus, aka HKA angle)

Mechanical Axis

Anatomical Axis

Considerations for Varus Knee Proximal Tibia Closing Lateral Wedge Opening Medial Wedge With Plate With External Fixator

Considerations for Valgus Knee Distal Femur (for deformities > 10 deg) Closing Medial Wedge Done from medial side Done from lateral side (Miniaci 1990) Opening Lateral Wedge Proximal Tibia (for deformities < 10 deg)

Hardware Options Opening Wedge Tibia Plates Arthrex Puddu Plate EBI VS Plate (reported to be 3x’s stronger in resisted bending than Puddu and screw heads sit into plate with lower profile)

15 degrees and higher have 3 holes on either side EBI VS Plate 15 degrees and higher have 3 holes on either side

Hardware Options Lateral Closing Wedge Tibia Plates Intermedics (Aaron Hoffman) Depuy Chandler Zimmer NexGen Osteotomy system (Noyes)

Intermedics

Depuy Chandler

Hardware Options Distal Femur Plates Blade Plate 95 Degree Condylar Plates (Richards, Synthes)

Issues with Varus Knee Closing Lateral Wedge Disadvantages More extensive dissection Disruption of tibiofibular joint or need to osteotomize the fibula Shortens the leg Patella infera due to patellar tendon contracture (however this is less with rigid fixation and early mobilization – Closkey CORR 2001)

Releasing the tether effect of fibula (Bauer JBJS(A) 1969) Shaft Osteotomy Excision of head Separation of joint

Risk of damage to the peroneal nerve (Kirgis JBJS (A) 1992)

Issues with Varus Knee Opening Medial Wedge Disadvantages Need for bone graft (ICBG or Allograft) Slower Wt. Bearing Patellar Infera due to raising of joint line (Wright AJKS 2001)

Issues with Valgus Knee Usually a wear pattern in flexion on lateral femoral condyle A. A straight closing medial wedge femoral osteotomy minimally addresses this issue B. A slight IR on the distal femur would help to unload this compartment - However this increases the lateral compartment pressure in PF joint

Issues with Valgus Knee Usually a wear pattern in flexion on lateral femoral condyle (cont.) C. Varus Tibial Osteotomy – maintains varus alignment in both flex/extension - However this creates an oblique joint line

Issues with Valgus Knee Plates do not sit well on the medial side A. Do not make a complete cut on the distal femur B. Put a plate on the lateral side using a closing medial wedge from lateral - this can be difficult but the plate sits down better C. Do an opening wedge from lateral - this requires bone graft

Issues with Valgus Knee The medial plate translates the distal femur lateral A. Place the plate lateral B. Do not complete the distal femur cut A medial plate has higher incidence of nonunion and plate breakage - Place the plate lateral on the tension side (Miniaci AJKS 1990)

Medial Plate Lateral Plate

Degree of Correction Distal Femoral Osteotomy for Valgus deformity No need for hypercorrection as in varus knee Correct to 0 Degrees Tibiofemoral Angle (McDermott JBJS(A) 1988) or to Mechanical Axis at 50% tibial joint line

Degree of Correction High Tibial Osteotomy for Varus Knee Coventry JBJS(A) 1985 – recommends correcting to 8 degrees of anatomic valgus based on a regression analysis of his cases Dugdale and Noyes CORR 1992 – recommend using a WBL through a point 62 – 66% of tibial width in the lateral compartment.

Degree of Correction High Tibial Osteotomy for ACL Deficient Knee or PLC Deficient Knee Noyes AJSM 2000 If knee is in varus and the cartilage surfaces are relatively well preserved then the restoration should be to a neutral position w/o overcorrection (ie 50% WBL)

General Rule of Thumb The height of tibial wedge is based on 1 degree of angular correction is equal to 1 mm This is true when the width of the tibial flare is 56mm (but in both M/F under correction would occur w/this formula) Avg male it is 80 mm Avg woman it is 70 mm

Wt. Bearing Line (WBL) Method Determine Tibial Width (TW) Draw the Mechanical Axis (CFH to CA) Mark the point on the 66% point on the knee joint line Draw lines from CFH and CA to the 66% point The angle from the two lines give the angle of correction needed

Mechanical Axis

Wt. Bearing Line (WBL) Method Confirmation at surgery Using Fluoroscopy use either an alignment rod or bovie cord placed at CFH and CA Confirm that the crossing point at the knee achieves the desired correction

Opening Medial Tibial Wedge Hernigou JBJS(A) 1987 93 knees w/11.5 yr avg F/U 90% G/E result at 5 yrs 45% G/E result at 10 yrs (42 knees) Deterioration occurred avg 7 yrs Best results w/no deterioration in the 20 knees w/7 or more degrees anatomic valgus correction

Closing Lateral Tibial Wedge Coventry JBJS(A) 1993 87 knees w/10 yr avg F/U Used staple fixation , immobilized and protected WB for 5 wks Endpoint of TKA or mod/severe pain 87% survival at 5 yrs 66% survivial at 10yrs 94% survival at 10 yrs when 8 or more degrees of anatomic valgus and w/in 1.17% of IBW

TKA after Osteotomy Haddad J Arth 2000 50 consecutive TKA p HTO compared to 50 age matched primary TKA (IB II, Kinemax, PFC) Interval from HTO to TKA avg 7.3 yrs (2-12) HTO TKA avg 23 minutes longer surgery (p<0.05) Higher patellar subluxation in HTO grp (p<.05) No difference in Revision Rate, KSS or HSS scores at avg F/U of 6.2 yrs

TKA after Osteotomy Meding JBJS(A) 2000 39 consecutive Bilateral TKA’s in which one side had previous HTO an avg 8.7 yrs earlier Avg age at surgery 67 yrs Avg F/U 7 yrs KSS and Function scores not significantly different Conclusions: No adverse effect from HTO

HTO vs. UKA Stukenborg-Colsman The Knee 2001 (Germany) Prospective Randomized controlled study HTO: 32 pts, avg age 67 at time of surgery Lateral closing wedge, 1/3 tubular 5 hole plate UKA: 28 pts, avg age 67 at time of surgery Tubingen pattern sliding UKA (Aesculap) KSS (Knee score, Fxn Score), Survival

HTO vs. UKA (cont.) Stukenborg-Colsman The Knee 2001 (Germany) Results at 7.5 yrs KS FS Survival HTO 74 71 60% UKA 76 59 77% No statistically significant differences

HTO w/Instability Badhe KSSTA 2002 Mixed group of patients with mixed treatment methods makes this a difficult paper to draw conclusions 14 patients avg 2.8 yrs F/U 5 patients with “Double Varus” – Varus & ACL deficient Treated with Closing lateral wedge HTO ACL reconstruction w/BTB

HTO w/Instability Badhe KSSTA 2002 14 patients 9 patients with “Triple Varus”- PLC, PCL, Varus 6 treated with ligament reconstruction 4 closing wedge HTO 2 opening wedge HTO 3 treated w/HTO only 1 closing 2 opening

HTO w/Instability Badhe KSSTA 2002 Results (Cincinnati Knee Rating System) Preop Postop Mean 53 74 DV-CW/ACL (5 pts) 55 80 TV-CW/LR (4 pts) 49 65 TV-OW/LR (2 pts) 77 TV-HTO (3 pts) 57 76

HTO w/Instability Badhe KSSTA 2002 Results Radiographic Alignment Preop 5 degrees varus Postop 6 degrees valgus