Osteoporotic fractures. (Featured CME Topic: Osteoporosis).

THE FOLLOWING is an outline of the epidemiology, biomechanics, treatment, and prevention strategies for osteoporosis. A suggested reading list is included at the end for those who want more detailed information.

I. EPIDEMIOLOGY

A. 1.5 million osteoporosis-related fractures annually

1. 700,000 vertebral fractures

2. 300,000 hip fractures

3. 250,000 distal forearm/wrist/Colles' fractures

B. $13.3 billion in direct costs annually

C. Projected $240 billion annually in osteoporosis costs by 2040

D. 33% of women >65 years of age have vertebral fractures

E. 32% of women and 17% of men >90 years of age have hip fractures

F. 33% of men >80 years of age have osteoporosis

II. BIOMECHANICS OF FRACTURE

A. Osteoporosis affects bone with high surface area

1. Trabecular bone resorption 8% per year

2. Cortical bone resorption 0.5% per year

B. Falls from standing exceed femur strength by 50% in elderly

C. Compressive strength is proportional to the square of bone mineral content

D. 50% to 58% of body weight is transmitted through L1 to L5

E. End-plate cross-sectional area increases caudally 

F. Study results conflict regarding bone density increase or decrease caudally

III. FRACTURE HEALING

A. Stages of fracture healing (Lane)

1. Impact

2. Induction

3. Inflammation

4. Soft tissue callus (chondroid)

5. Hard tissue callus (osteoblastic)

6. Remodeling

B. Altered healing in osteoporosis

1. Hard tissue callus formation and remodeling phases

2. Osteoporosis results in delayed mineralization and remodeling

3. Bone scans may show activity up to 3 years after fracture (1)

IV. MANAGEMENT OF FRACTURES

A. Perren(2)

1. Anatomic reduction

2. Stable internal fixation

3. Preservation of the blood supply using atraumatic technique

4. Early active mobilization

B. Treatment protocol from Cornell Medical Center--Hospital for Special Surgery

1. Rapid, definitive fracture care, keeping surgical procedure simple

2. Stable fracture fixation, permitting early return to function/weight bearing

3. Avoid excessive periosteal stripping

4. Utilize indirect reduction techniques

C. Important aspects of treatment

1. Replace anticipated deficits in calcium reserve

2. Deficits are a concern, since a 10% systemic bone loss has been noted in animal subjects after long-bone fracture

3. Rule out underlying metabolic bone disease 

V. FRACTURES OF THE SPINE

A. Types of spinal fracture

1. Compression fractures

2. Burst fractures

B. Rarely neurologic compromise

C. Rarely unstable

1. Indications of instability

a. Neurologic deficit

b. Kyphosis >30[degrees]

c. Compression >50%

d. Translation >4 mm

e. Interspinous-process widening

D. Treatment of spinal fracture

1. Analgesics

2. External bracing (Jewett, Thoracolumbosacral orthosis)

3. Activity modifications

4. Maintain weight-bearing activities

5. Identify underlying cause

6. Pharmacologic management

a. 48% reduction in incidence of fractures

b. Calcium and vitamin D

c. Hormone replacement therapy 

d. Augmentation agents

e. Calcitonin 

f. Alendronate 

g. Pamidronate

7. Vertebroplasty or kyphoplasty

8. Open reduction with internal fixation (very rarely)

9. Internal fixation

a. Standard indications

b. Often requires 360[degrees] procedure

c. Augmentation with polymethylmethacrylate or hydroxyapatite 

d. Structural grafting anteriorly

e. Polysegmental fixation posteriorly

f. Less correction expected

g. Do not stop instrumentation within a kyphotic segment

h. Postoperative bracing encouraged

i. Maximize preoperative treatment

E. Spinal fracture summary

1. Operative indications similar to patients with normal bone

2. Nonoperative measures first

3. Often anterior and posterior procedures needed

4. Do not hesitate to augment screws

VI. HIP FRACTURES

A. 25% of women >60 years of age have hip fractures

B. 12% to 20% mortality

C. 50% able to return to independent ambulation 

D. Reason for 60,000 nursing home admissions annually

E. Incidence is clearly related to osteoporosis

F. Fall resulting in blow to trochanter 

G. Femoral neck fracture

1. High incidence of nonunion/avascular necrosis

2. Closed reduction/pinning

3. 14% nonunion

4. 15% avascular necrosis and symptomatic collapse

5. Higher incidence of failure in osteoporosis due to loss of fixation

6. Arnold's study (3)

a. Closed reduction with internal fixation

b. 80% good or excellent results

c. Requires near anatomic reduction

7. Hemiarthroplasty indications

a. Active household or community ambulators

b. Patients with severe osteoporosis

c. If unable to obtain stable reduction

H. Hemiarthroplasty vs pinning (4)

1. Study of 215 displaced fractures treated with closed reduction with internal fixation

a. 63 (29%) had died by 2 years

b. Nonunion in 39 patients (18%)

c. Avascular necrosis in 14 patients (6.5%)

d. Only 36 (17%) required reoperation

e. Survival at 6 months comparable between both procedures

i. 4% early mortality

ii. 5% 6-month mortality

2. Hemiarthroplasty disadvantages:

a. 1% to 2% late dislocations

b. 2% late loosening at 5 years requiring revision in 1 patient

VII. INTERTROCHANTERIC FRACTURES

A. Incidence of malunion and varus may be disabling

B. Avoid shortening the limb

C. Avoid external rotation deformity

D. Implant considerations

1. Load bearing--fixed nail-plate construct

2. Intermediate--sliding nail-plate construct

3. Load sharing--intramedullary nail-screw construct

E. Medial displacement osteotomy 

1. Puts fracture in most stable configuration

2. Less stress on implant

3. Results in shortened limb and weak abductors

F. Techniques to enhance fixation

1. Screw must be central in head/neck

2. Must engage subchondral bone within 11 to 25mm range (5)

a. Valgus screw/plate-140[degrees] optimal fragment if possible

b. Basicervical fracture smay be best treated with sliding screw/plate device (6)

3. Polymethylmethacrylate used to augment fixation allows early weightbearing

4. Unstable fractures treated with short-barrel implant

5.Reduce posteromedial (lesser trochanter) fragment to increase strength of construct

VIII. FAILURES IN HIP FRACTURES

A. Causes of redisplacement and reoperation

1. Osteoporosis

2. Fracture displacement

3. Collapse of femoral head

4. Bone mineral content <0.4 g/[cm.sup.2] results in a much higher failure rate

IX. PROXIMAL HUMERUS FRACTURE

A. 5% of osteoporotic fractures

B. 80% nondisplaced

1. Nondisplaced fractures--immobilization in sling and early motion as pain subsides

2. Full passive range of motion encouraged by 3 to 4 weeks, active range of motion at 5 to 6 weeks

C. Surgical options

1. Closed reduction, percutaneous pinning

2. Pinning less effective in poor bone quality

3. Greater tuberosity fracture needs reduction and possibly rotator cuff repair

4. Comminuted fractures

a. Open reduction with internal fixation using screws and tension band wiring if possible

b. 3 or 4 part fractures should be treated with hemiarthroplasty

c. Repair rotator cuff

X. COLLES' FRACTURE

A. Fracture of the wrist

B. Involves dorsal displacement of the radius

C. May or may not involve the ulna 

D. Often results in an ulnar styloid fracture

E. Fractures intra- and/or extra-articular

F. Closed reduction and casting

1. Adequate reduction

a. Neutral angulation 

b. No radial shortening

c. Minimal dorsal comminution 

d. All types of deformity better tolerated in elderly so use judgment!

2. Long arm cast 2 to 4 weeks

3. Short arm cast another 4 to 6 weeks

4. Incidence of reflex sympathetic dystrophy, stiffness, malunion

a. 52% complication rate with pins and plaster

G. Percutaneous pinning/external fixation

1. Unstable, severely comminuted fractures

2. Fixation--6 weeks

3. Limit distraction to 5 mm, and maintain wrist in neutral position or extension

4. If not healed, remove fixator and cast until clinically healed

5. 80% to 90% good or excellent results in functional outcome

6. 15% to 60% complication rate

H. Open reduction with internal fixation

1. Medhoff plates becoming popular

2. Reserved for grossly displaced intraarticular fractures

3. Augment with bone graft

4. Research into injection of hydroxyapatite to augment fracture

I. Treatment summary

1. Provide stable fixation

2. Use standard anterior oblique technique

3. Interfragmentary lag screws where applicable

4. Augmentation when necessary

5. External protection

6. Maintain function and weight-bearing

XI. AMERICAN ACADEMY OF ORTHOPAEDIC SURGEONS RECOMMENDATIONS FOR PREVENTION OF FALLS

A. Make the home safe

B. Special attention to carpets and handrails

C. Maintain good lighting/night-lights

D. Eliminate medications that alter balance when possible

E. Home evaluation by therapist/registered nurse may be helpful

XII. PREVENTION OF OSTEOPOROSIS

A. Medications

B. Weight-bearing exercise

C. Eliminate risk factors such as smoking, caffeine, and alcohol

D. Replace anticipated calcium deficits in fracture patients

E. Maximize nutrition

References

(1.) Einhorn TA, Bonnarens F, Burstein AH: The contributions of dietary protein and mineral to the healing of experimental fractures: a biomechanical study. J Bone Joint Surg Am 1986; 68:1389-1395

(2.) Perren SM: Basic aspects of internal fixation. Manual of Internal Fixation: Techniques Recommended by the AO-ASIF Group. Mueller ME (ed). New York, Springer-Verlag, 3rd Ed, 1995, pp 1-3

(3.) Arnold WD, Lyden JP, Minkoff J: Related articles, treatment of intracapsular fractures of the femoral neck, with special reference to percutaneous Knowles pinning. J Bone Joint Surg Am 1974; 56:254-262

(4.) Stromqvist B, Hansson LI, Nilsson LT, et al: Hook-pin fixation in femoral neck fractures: a two-year follow-up study of 300 cases. Clin Orthop 1987; 218:58-62

(5.) Larsson S, Friberg S, Hansson LI: Trochanteric fractures. influence of reduction and implant position on impaction and complications. Clin Orthop 1990; 259:130-139

(6.) Blair B, Koval KJ, Kummer F, et al: Basicervical fractures of the proximal femur, a biomechanical study of 3 internal fixation techniques. Clin Orthop 1994; 306:256-263

Suggested Reading

1. Benum P: The use of bone cement as an adjunct to internal fixation of supracondylar fractures of osteoporotic femurs. Acta Orthop Scand 1977; 48:52-56

2. Castel H, Bonneh DY, Sherf M, et al: Awareness of osteoporosis and compliance with management guidelines in patients with newly diagnosed low-impact fractures. Osteoporos Int 2001; 12:559-564

3. Cornell CN: Management of fractures in patients with osteoporosis. Orthop Clin North Am 1990; 21:125-141

4. Dalen N, Jacobsson B: Factors influencing the incidence of reoperation after femoral neck fractures. Int Orthop 1985; 9:235-237

5. Goodman SB, Schatzker J: Internal fixation of femoral neck fractures: a prospective study. Can J Surg 1986; 29:351-356

6. Kawagoe K, Saito M, Shibuya T, et al: Augmentation of cancellous screw fixation with hydroxyapatite composite resin (CAP) in vivo. J Biomed Mater Res 2000; 53:678-684

7. Kopylov P, Aspenberg P, Yuan X, et al: Radiostereometric analysis of distal radial fracture displacement during treatment: a randomized study comparing Norian SRS and external fixation in 23 patients. Acta Orthop Scand 2001; 72:57-61

8. Koval KJ, Sala DA, Kummer FJ, et al: Postoperative weight-bearing after a fracture of the femoral neck or an intertrochanteric fractuce. J Bone Joint Surg Am 1998; 80:352-356

9. Lansinger O, Bergman B, Courmner L, et al: Tibial condylar fractures: a 20 year follow-up. J Bone Joint Surg Am 1986; 68:13-18

10. Little DG, Cornell MS, Briody J, et al: Intravenous pamidronate reduces osteoporosis and improves formation of the regenerate during distraction osteogenesis. a study in immature rabbits. J Bone Joint Surg Br 2001; 83:1069-1074

11. Lustenberger A, Ganz R: Epidemiology of trochanteric femoral fractures over 2 decades (1972-1988) [in German]. Unfallchirurg 1995; 98:278-282

12. Ostrum RF, Geel C: Indirect reduction and internal fixation of supracondylar femur fractures without bone graft. J Orthop Trauma 1995; 9:278-284

13. Rubin R, Trent P, Arnold W, et al: Knowles pinning of experimental femoral neck fractures: biomechanical study. J Trauma 1981; 21:1036-1039

14. Schatzker J, Ha'eri GB, Chapman M: Methylmethacrylate as an adjunct in the internal fixation of intertrochanteric fractures of the femur. J Trauma 1978; 18:732-735

15. Schatzker J, Horne JG, Sumner-Smith G, et al: Methymethacrylate cement: its curing temperature and effect on articular cartilage. Can J Surg 1975; 18:172-175, 178

16. Sheehan J, Mohamed F, Reilly M, et al: Secondary prevention following fractured neck of femur: a survey of orthopaedic surgeons practice. Ir Med J 2000; 93:105-107

17. Sjostedt A, Zetterberg C, Hansson T, et al: Bone mineral content and fixation strength of femoral neck fractures. a cadaver study. Acta Orthop Scan 1994; 65:161-165

From Campbell Clinic Orthopedics, Germantown, Tenn.

Presented at the Fifth Annual Southern Medical Association Conference on Osteoporosis, Amelia Island, Fla, February 21-24, 2002.

Reprint requests to Douglas A. Linville II, MD, Scoliosis and Spine Surgery Clinic of Memphis, 6005 Park Ave, Suite 510, Memphis, TN 38119.