Best Treatment for a Salter–Harris Type I or II Growth Plate Fracture.

With a transverse fracture through the hypertrophic zone (Type I), the germinal layer usually is not primarily involved, although there may be some microfracture that extends into the germinal zone,⁶ and significant growth disturbance is uncommon, unless there is associated injury to the blood supply.⁵ In the more common, type II fracture, which runs through the growth plate with a triangular fragment of metaphysis (Thurston–Holland fragment), there is usually an intact periosteal hinge⁵ that can aid closed reduction.

In laboratory rats after a type I or II fracture, a brief growth arrest is noted. However, the growth plate appears normal after 25 days other than a thickened hypertrophic zone.⁷

Specific treatment depends on the site of the fractures. There are no high-level studies that compare open with closed treatment or use of fixation. The accepted wisdom is that reduction should be gentle to avoid scraping the growth plate on bone fragment or damaging the germinal layers during manipulation.^{1,5, 8} It is generally agreed that closed reduction and casting is successful; however, that it may be necessary to use internal fixation after open or closed reduction if it is unstable.⁸ In some circumstances, the periosteum may become interposed into the fracture and block satisfactory or anatomic reduction requiring exploration.⁹

Best Treatment for Salter–Harris Type III or IV Growth Plate Fractures.

In both type III and IV fractures, the fracture includes a growth plate injury with a disruption in the articular surface of the joint. Although a type III fracture runs through the epiphysis and a type IV runs through the metaphysis and epiphysis, they may both result in malalignment of the layer zones of the growth plate and lead to development of a bony bridge.

No randomized studies have compared open with closed treatment or use of fixation. According to Bright,⁹ anatomic alignment of the growth plate and articular surface is important and requires anatomic reduction and internal fixation. There are case reports of nondisplaced fragments becoming displaced if fixation is not used.

No studies have compared methods of fixation. It is generally accepted that nonthreaded wires should be used in the epiphysis or metaphysis that run parallel to the growth plate.⁸ Alternatively, screw fixation parallel to the growth plate can be used. If stable anatomic fixation cannot be attained with transverse pins, it is also accepted that oblique nonthreaded wires across the growth plate may be used.⁸ There have been case-series reports (Level IV evidence) of the use of biodegradable rods, Polylactide-glycolide polymer,¹⁰ across the growth plates without disturbance of growth.

Best Treatment of Salter–Harris Type V and “VI” Fractures.

Compression or crush injuries to the growth plate (type V) are rarely diagnosed acutely. Some debate exists in the literature whether this mechanism exists. Although several reports have demonstrated that growth plate compression injuries occur, they usually result in a complete arrest (rather than partial growth arrest that is indicated in the Salter–Harris article).¹ The average time until diagnosis of this type of injury is 17 months.

Although not included in the original Salter–Harris classification, a type “VI” fracture is included in Rang’s book.¹¹ He reports that Kessel suggested an additional type of growth plate injury, that is, an injury to the periosteum or perichondrial ring resulting in a bony bridge. It is suggested that this may lead to angular deformity from a bone bridge. Few cases series have reported this injury type.

Because these fractures are not usually diagnosed acutely, there is no specific treatment recommendation at the time of injury. If a Salter–Harris type V or “VI” growth plate injury does result, further treatment may be necessary to prevent or correct deformity.

Acetabular Triradiate Cartilage Fractures.

Injury to the acetabular triradiate growth plate cartilage is rare, but it may be associated with progressive acetabular dysplasia and subluxation of the hip. Bucholz and colleagues¹² found nine patients with triradiate growth plate injury (Level IV evidence). Shearing (SH type I or II) injury seems to have a favorable prognosis. However, a crushing SH type V growth plate injury has a poor prognosis, with premature closure. Prognosis is dependent on the age of the patient at the time of injury and on the extent of chondro-osseous disruption.

DISTAL FEMUR FRACTURES. Fractures of the distal femoral growth plate account for approximately 5% of growth plate injuries. From case reports, it is apparent that damage to the neurovascular structures in the popliteal fossa may occur when displacement occurs in the saggital plane and should be sought for and treated.

Approximately 50% of distal femur growth plate fractures are associated with growth disturbance, even the type I or II fractures (Level IV evidence, case series).^13,14

Expert advice is that closed reduction should also be attempted for all minimally to moderately displaced Salter–Harris type I and II fractures.¹⁵ However, a study of 10 distal femoral physeal fractures found that 7 displaced, and the authors suggest that internal fixation should be used.¹⁶ Fractures with greater displacement, especially those with a hyperextension pattern, are associated with an increased risk for redisplacement; therefore, percutaneous fixation is recommended.¹⁷

Salter–Harris type II fractures can be stabilized by fixation across the Thurston Holland metaphyseal spike if it is large. Percutaneous screws are preferred for fixation if they can be inserted without crossing the physis. If metaphyseal stability cannot be obtained, Salter–Harris type I and II fractures can be fixed with one or two smooth Steinmann pins from the epiphysis to the metaphysis. If the pins are left outside of the skin, they can cause irritation and may even lead to infection septic arthritis.¹⁵