Delayed Union or Nonunion Of Femoral Neck in Young Adults

Femoral neck fractures occur in younger patients, frequently as a result of high-energy trauma. Prognosis is worse in younger patients. Dedrick et al reviewed 32 cases of femoral neck fractures in young adults and found 20% nonunion and 36%avscular necrosis. In these individuals extreme force is required to produce fracture which explains the increased incidence of AVN & nonunion. In underdeveloped countries because of poverty, ignorance & lack of facilities these delayed presentation or nonunion is common.

Definition of non union

· # where reparative process has halted (Cave 1958)

· A particular # not united in the time it normally unites

- cannot be uniformly applied to all bones

· FDA panel definition(1986)

– Min. 9 months has elapsed after injury & no progressive sign of healing for 3 months.

– can’t be applied universally

Delayed presentation

(Late presenters)

· 3weeks to 3 months termed as late presenters

· Unique problem specially in our country

· Neck gets absorbed and limb becomes short

· Causes problems in management(Meyers 1974)

Why is non union common after fracture NOF?

· Absence of cambium layer of periosteum of femoral neck leads to decrease in the healing potential(Phemister, 1939)

· Continuous Synovial bathing

· Avascularity- as healing callus comes from the neck shaft side the fracture because of avascularity of the head(Hulth 1961)

· High velocity trauma in young adults

Factors contributing to nonunion of femoral neck

· Inaccurate reduction

· Unsound or loss of fixation

· Vascular insufficiency

· Posterior comminution

· No treatment

Avascular Necrosis & Non union

· Go hand in hand

· Pts with normal bone stock have higher risk of AVN(Portzman & Burkhalter 1976)

· Avascularity has a great bearing on the outcome of treatment

· Quite a few non unions have avascular heads but non union is not always a certainty in avascular heads(Marti 1993)

Posterior Comminution

· Present in >60% of pts who later developed nonunion(Banks 1974,Scheck 1980)

No Treatment

· Untreated displaced fractures almost always will go for non union unless proved otherwise (Rockwood & Green, 1990)

Investigation:

· Plain X-rays

· Bone Scanning

· Tomography or high resolution CT scan

· MRI

Treatment:

Although prosthetic replacement frequently is considered for the treatment of displaced fractures in elderly patients, efforts are focused on preserving the femoral head in physiologically younger patients. Surgical options are mainly divided into head salvage procedures & sacrificing procedures.

Salvage procedures: If femoral head is viable and adequate neck is remaining non unions can be treated by:

· Fixation alone

· Osteotomy+/-fixation

· Muscle pedicle bone grafting+/-fixation

· Cortical bone grafting+/-fixation

· Cancellous bone grafting+/-fixation

· Combination of osteotomy and bone grafting

Fixation alone:

· Could be tried within 3 weeks of injury (late presenters or untreated fractures) which are undisplaced or are reducible.

· In established cases of nonunion just fixing the head will not suffice(Rocked & Green 1990)

Osteotomy+/-fixation

Ø Pauwel’s osteotomy

Ø Dickson’s geometric osteotomy

Ø McMurrey’s osteotomy

Ø Schanz angulation osteotomy

Pauwel’s osteotomy 1935

· Mechanical problem rather then a biological one

· Abduction osteotomy at intertrochanteric level

· Converts shearing force into compressive force

· Based on Pauwel’s classification

· AVN without segmental collapse is NOT a contraindication”.

· 86% union in 50 nonunions Marti et al (1993).

Dickson’s geometric osteotomy 1947

· Indications

– Nonunion with viable femoral neck & varus displacement

· Advantages

– Easy to perform

– Immediate stability can be provided

– Converts sheer force into compressive force

McMurrey’s Osteotomy 1936

· Displacement type of osteotomy

· Puts the shaft beneath the head

· Line of wt bearing shifted medially

· Makes the # line horizontal

· Shortens the lever arm between the trochanter and the hip and leads to early OA changes

· Makes future arthroplasty difficult

· Not practiced and no longer popular

Schanz angulation osteotomy

· Made distal to lesser trochanter.

· Angulated so as to gain length

· Line of wt bearing shifted medially

· Not popular

Muscle pedicle bone grafting+/- fixation

· Useful in delayed presenters as well as non union

· Insertion Quadratus femoris muscle to the femur is mobilised with femoral cortex and is fixed across the fracture site posteriorly.

· Meyer et al (1974)

– 11% segmental collapse at 2 years

– 90% union

Muscle pedicle bone grafting +/- bone grafting

· Bakshi(1983,86,92)

– Used gluteus minimus with attached bone block

– Fixed anteriorly

– Used in proven nonunions with absorbed necks

– 75% good results

· Pati et al (1998)

– used screw fixation + MPBG

– 11% segmental collapse as compared to 32% with fixation alone in delayed presenters

Cortical bone grafting +/- fixation (Nagi et al1998)

Fibula used is successfully

– 80% good results in late presenters

– All bad results were in nonunions

– Uses single screw + BG

– Puts the pt in hip spica

– Pts. presenting as late as 10 months were included in the study

Cancellous grafting +/- fixation (Deyerly 1980& Dickson 1953)

– Promising results

– Window created anteriorly in the head and neck

Sacrifice

· Unipolar arthroplasty

· Bipolar arthroplasty

· Total hip arthroplasty

· Girdlestone arthroplasty

Decision Making

Late presentation:

Irrespective of vascularity of the head, good reduction achieved and neck shaft angle maintained &

– If presented within 3 weeks:

Fix it

– If presented after 3 weeks up to 3 months

Fixation +BG (Cortical)

Muscle pedicle bone grafting

– If presented after 3 months with shortening and varus of the head

Pauwell’s osteotomy+/- BG

Dickson’s geometric osteotomy

– If there is segmental collapse

Replacement arthroplasty

Arthrodesis

Confirmed Non unions

Young adults (20-40) (neck is not absorbed and the head is viable)

– Fixation alone will not work

– Augment it with BG or osteotomy or MPBG

– Preserve the head as far as possible

If neck is absorbed and the head is not viable

· Arthrodesis

· Girdlestone arthroplasty

· Bipolar after proper explanation to the pt if acetabular cartilage good.

· THR if articular cartilage is of poor quality

Middle age group (40-60)

– If head is viable and neck is not resorbed

Fixation+ BG

Osteotomy if leg is short

– If there is segmental collapse

Bipolar or THR

– If no segmental collapse but evidence of AVN

Pauwell’s osteotomy

MPBG

Dr Mallinath Gidaganti

MS Orthopaedics

HOSMAT Hospital, Bangalore.