INCIDENCE OF INTERNAL

DERANGEMENTS OF KNEE WITH

IPSILATERAL FEMORAL SHAFT

FRACTURE

ABSTRACT NUMBER : 120

Diaphyseal femur fractures are mostly the result of high

energy trauma .

Femoral shaft fractures are often associated with bony and

soft tissue injuries to the ipsilateral knee, and a high index of

suspicion is necessary to identify these lesions.

These ligament injuries are usually silent or occult and many

of them progress undiagnosed at this stage, with negative

consequences for patients and orthopedicians.

INTRODUCTION

Assessment of the ligaments of the knee by clinical

examination in the emergency room is difficult to perform as

the distal segment of the fractured femur is unstable; and

movement of the affected knee may cause more pain or

discomfort to the patient.

The clinical methods to assess the knee joint for

intraarticular soft tissue injuries are either under anesthesia

preoperatively or after fixation postoperatively.

The disadvantage of examination under anesthesia

preoperatively is meniscal injuries cannot be assessed

optimally.

Hence we hypothesised that a preoperative MRI of the

affected knee joint, will aid in the diagnosis of a soft tissue

injury.

OBJECTIVES

To anticipate meniscal, ligamentous and retinacular injuries of

the knee in patients sustaining ipsilateral femoral shaft

fractures.

To identify the type and character of intraarticular ligamentous

injuries of the knee joint following ipsilateral femoral shaft

fractures.

To emphasize the need for an MRI of the knee with ipsilateral

femoral shaft fractures in the preoperative period.

To establish the advantages of MRI knee in tailoring the

management strategy of femoral shaft fracture and to address

the issue of intraarticular soft tissue injuries.

METHODOLOGY

STEP 1

• Patients with femoral shaft of femur fracture• Patients fulfilling the inclusion criteria and

exclusion criteria were selected

STEP 2

• Patient explained about the advantage of the investigation

• Written consent was obtained

STEP 3

• MRI of ipsilateral knee was done and findings were noted

• All findings were tabulated in a master sheet and incidence was calculated.

Methodology

INCLUSION CRITERIA :1) Age group: >15 years.2) Patients with fracture shaft of femur.

EXCLUSION CRITERIA:1) Patients with periprosthetic, pathologic fractures or

polytrauma.2) All patients with previous knee injuries or previous

knee surgery.3) Patients on cardiac pace makers or metal implants.4) Any other contraindications for an MRI.

Out of 40 patients, there was incidence of intraarticular soft tissue injuries in 26 patients (65%) .

RESULTS

Injury Number of Cases Anterior cruciate ligamentComplete tearPartial tearTotal ACL

 8 (20%)5 (12.5%)

13 (32.5%)

Posterior cruciate ligamentComplete avulsionComplete tearPartial tearTotal PCL

 2 (5%)2 (5%)

5 (12.5%)9 (22.5%)

Medial collateral ligament (MCL)Complete tearPartial tear

4 (10%)2 (5%)2 (5%)

Lateral collateral ligament (LCL)Complete tearPartial tear

4 (10%)2 (5%)2 (5%)

MenisciMedialAnterior horn Posterior horn LateralAnterior horn Posterior horn Total menisci

 10 (25%)1 (2.5%)5 (2.5%)6 (15%)2 (5%)2 (5%)

16 (40%)

Extensor mechanismPatellar tendon partial tear Patellar tendon complete tear Quadriceps tendon partial tear Total extensor mechanism

 1 (2.5%)1 (2.5%)2 (5%)

4 (10%)

Retinacular tears 3 (7.5%)Cartilage 0 (0%)BoneContusion Occult fracture

 32 (80%)3 (7.5%)

NUMBER OF CASES PERCENTAGE

Effusion 40 / 40 100 %

Bone contusions 32 / 40 80 %

ACL injury 13 / 40 32 %

PCL injury 9 / 40 22 %

MCL injury 4 / 40 10 %

LCL injury 4 / 40 10 %

Medial meniscus injury 10 / 40 25 %

Lateral meniscus injury 6 / 40 15 %

Capsular tears 3 / 40 8 %

Patellar tendon injury 2 / 40 5 %

STRUCTURE INVOLVED

NUMBER OF CASES PERCENTAGE

ACL 4 10 %

PCL 4 10 %

LCL 1 2.5 %

MCL 3 7.5 %

MM 2 5 %

LM 1 2.5 %

MM + LM 1 2.5 %

ACL + PCL 2 5 %

ACL + MM 2 5 %

ACL + PCL + MM 1 2.5 %

ACL + PCL +LCL + MM + LM 1 2.5 %

PCL + LCL + MM 1 2.5 %

ACL + PCL + LM 1 2.5 %

ACL + LCL + MM + LM 1 2.5 %

ACL + MM + LM 1 2.5 % No ligamental or meniscal

injury 1435 %

TOTAL NUMBER OF CASES 40 100 %

ACL

PCL

LCL

MCL

MM

LM

MM + LM

ACL + PCL

ACL + MM

ACL + PCL + MM

ACL + PCL +LCL + MM + LM

PCL + LCL + MM

ACL + PCL + LM

ACL + LCL + MM + LM

ACL + MM + LM

No ligamental or meniscal injury

De Campos 1994

(Arthroscopy)

Blacksin 1998  

 (MRI)

Dickson 2002

(MRI)

Our study 2014

(MRI)

Number of patients

40 34 27 40

Total abnormal 22 (55%) 34 (100%)+ 19 (70%) 26 (65%)

ACL 21 (53%) 2 (6%) 5 (19%) 13 (32.5%)

PCL 3 (7.5%) 7 (21%) 2 (7%) 9 (22.5 %)

LCL 5 (12.5%) 2 (6%) 8 (30%) 4 (10%)

MCL 11 (27.5%) 13 (38%) 11 (41%) 4 (10%)

Total meniscus 13 (32%) knees 10 (30%) 11 (41%) 16 (40%)

Lateral meniscus

8 (20%) 4 (12%) 7 (26%) 6 (15%)

Medial meniscus

5 (12%) 6 (18%) 4 (15%) 10 (25%)

Bone bruise N/A 32%

1 (3%) occult tibial plateau

fracture

25 (93%) 32 (80%)

Effusion N/A 33 (97%) N/A 40 (100%)

Why a pre-operative MRI? Why not post-operative MRI?

In order to reduce the error factors addressed in the

previous studies like iatrogenic MCL tears during

interlocking screw fixation,

MRI of patients with stainless steel induced artifacts in

retrograde intramedullary nailing were excluded in the

previous study, which may have caused variation in the

true incidence of internal derangements of the knee.

Antero – Lateral ligament (ALL)

ALL injury in MRI

Proximal ALL injury Distal ALL injury

Incidence of ALL injury in our study

Incidence – 11 cases (44%) Proximal ALL injury – 4 cases

(16%) Distal ALL injury – 5 cases

(20%) Proximal + Distal ALL injury – 2 cases (8%)

Conclusion

Femoral shaft fractures exerted by high velocity forces have been

proven to cause internal derangements in the ipsilateral knee along

with soft tissue injuries, by exhaustive analysis by various

orthopedists, radiologists through physical examination, X-rays

analysis, MR imaging and arthroscopic evaluation.

The incidence of internal derangements of the knee in our study

using MRI is similar to those reported in the previous studies using

arthroscopy and/or MRI as diagnostic tools.

MR imaging of the knee is considered advantageous to have

shown

a significant increase in the incidence of ligamentous injuries

in the knee from 5% in earlier studies to 70% in recent studies;

in the identification of clinically suspected meniscal injuries

through a non-invasive approach;

and a suitable non- radiational imaging modality for

arthroscopic blind spots.

In a case of femoral shaft fracture due to a high velocity trauma,

the attending surgeon must beware of an internal derangement

of the knee and must investigate for knee instability, ligament

laxity.

Currently there is no general consensus on the use of the MRI

scan as a standard diagnostic preoperative tool. It is usually

preserved for patients who develop joint instability or soft tissue

related symptoms(knee locking, persistent joint pain) at a

secondary stage following fracture healing and weight bearing.

Take home message