Cpt mink
- 1. -mink-
- 2. types of deformity (1) anterolateral bowing associated with the limb-threatening condition pseudarthrosis, or dysplasia, of the tibia, although a benign form also exists; (2) posteromedial bowing, usually benign (3) anterior or anteromedial bowing with congenital deficiency of the fibula.
- 3. CPT is actually a rare disease entity Incidence 1 : 140.000- 190.000 births Subject to a wide range of scientific discussion Remains one of the most challenging cases a pediatric orthopedic surgeon treats
- 4. CPT dysplasia of the bone with failure of normal bone formation Segmental weakening Anterolateral angulation Pathologic fracture
- 5. Etiology as of yet still unclear Considered a specific type of non union or potential non union that occurs through a hamartomatous area of fibrous tissue at the tibia. The dysplasia is present at birth and associated with anterolateral bowing of tibia, usually at the junction of middle and distal thirds
- 6. epidemiology study : 340 patients from 13 countries Symptoms of NF-1 were present in 54.7%, the rest has no clinical signs of NF-1 (occult?) Correlation? Only 6% of NF-1 patients has CPT
- 8. Neurofibromatosis 1: ◦ A single copy of the NF1 gene is defective ◦ The other copy is functional ◦ CPT : “Second hit theory” local somatic mutation
- 9. Model of doubly-inactivated NF gene (NF-1null) NF-1null mice has poor healing and non-union of fracture site Abundant un-differentiated fibrotic tissue at callus site
- 11. dysplasia present since birth leading to progressive anterolateral bowing of the tibia eventually within 2 to 5 years a pathologic fracture occurs resultant pseudoarthrosis develops because of the non union.
- 12. Methods of Treatment? ◦ Difficult to achieve union ◦ Generally poor prognosis regarding the quality and longevity of achieved union ◦ Function of limb in the future? ◦ No consensus Boyd: “the success in treating CPT can be known only by following the patient to maturity”
- 13. Goals of Treatment : 1. To obtain and maintain union while optimizing the function of the involved extremity 2. To minimize the angular deformity (ankle valgus) and LLD
- 14. Problems of management of established pseudarthrosis : Obtaining union Preventing shortening of the limb Tendency of refracture after union
- 15. Non surgical treatment : brace before weight bearing : AFO After weight bearing : KAFO Surgical treatment Basic principles of treatment Resect pseudarthrosis Correct angular deformity Stable fixation Autologous bone grafting Tadjihan : (1)alignment of the leg must be maintained, (2)permanent intramedullary fixation to maintain such alignment or to provide internal bracing for a united tibia is desirable
- 16. Currently only three modalities have achieved union rates above 70% :
- 19. 23 pts with CPT treated by intramed rodding f/u at 4-14 years 11 achieved unequivocal union with full weightbearing function and maintenance of alignment requiring no additional surgical treatment 9 achieved equivocal union with useful function, with the limb protected by a brace, and/or deformity 3 had persistent nonunion or refracture, requiring full-time external support
- 21. Dr. Benjamin Joseph’s method using an intramedullary rod fixation augmented by onlay grafting Good results were obtained Long term follow up at 10 years published in a subsequent article also showed good long term results
- 23. Illizarov technique offers advantage of : ◦ bone lengthening ◦ correction of deformity ◦ excellent union rates
- 24. data of 340 patients who underwent 1287 procedures The Ilizarov technique emerged as being the optimal method, having the highest rate of fusion (75.5%) of pseudarthrosis and high rate of success in correction of the additional deformities
- 25. tibial defect greater than 3 cm after resection of the pseudarthrosis fibula Pseudarthrotic segment is resected and replaced by living contralateral
- 27. Advantages: Primary bone lengthening Correction of deformity Union occurs in relatively short period of time Disadvantages : Technically demanding procedure Requires microsurgical experience Involves operation on normal leg Major problem is development of valgus deformity of normal ankle
- 29. Used to augment healing effort of the techniques above ◦ Rh-BMP2 : studies support faster repair but not higher union rate and no data yet on maintenance of union ◦ Rh-BMP7 : still under investigation, some case reports no significant results Rh-BMP2 soaked sponges applied around excised pseudoarthrosis site after immobilization by intramedullary rod
- 32. Primary surgical intervention augmented with rhBMP-2 resulted in radiographic union of the pseudarthrosis in five of the seven patients at an average of 6.4 months The primary functional outcome was classified as grade 1 for five patients, grade 2 for one, and grade 3 for one
- 33. 20 patients in series treated with a combination of periosteal grafting and fixation with intramedullary rod and Illizarov ring fixator all achieved union, with some (8 patients) experiencing subsequent refracture Good results achieved, no long term morbidities found
- 36. Comparable results with Ilizarov technique in achieving union Considered easier to achieve multiplanar correction by gradual correction of deformities
- 37. Case report of 16 yo pt with CPT and histroy of 14 prior surgeries which has failed to achieve union success of TSF in obtaining easy correction of a severe deformity with improvement of contact area, which in return promotes healing, in addition to permitting excellent stability and ability to an early weight bear
- 38. A group of pediatric orthopedic surgeons employed the Masquelet technique in CPT Masquelet technique originally was developed as a method of treatment for long bone defects Result at two years was excellent
- 41. Very seldom a consideration in the early management of the child with CPT but consider in : ◦ anticipated shortening limbs of more than 2 or 3 inches (5 to 7.5 cm), ◦ a history of multiple failed surgical procedures ◦ stiffness and decreased function of a limb that would be more useful after an amputation and fitting with a prosthesis ◦ functional loss resulting from prolonged medical care and hospitalization. Ankle disarticulation (Syme or Boyd type) rather than amputation through the pseudarthrosis or tibial bone ◦ prevents spike formation at the transected bone end and subsequent stump revisions and covers the stump with end- bearing heel pad skin. ◦ Persistent motion at the pseudarthrosis site is managed by the prosthetic socket.
- 42. Electrical Stimulation. early research : increased calcification of fibrocartilage, increased angiogenesis, & decreased osteoclastic resorption application of pulsed electromagnetic fields. adjunct to conventional bone grafting and internal fixation confounded by an inability to separate the effect of the stimulation from the effect of other treatment modalities
- 43. Stifness of ankle & hindfoot ◦ Even if stiffness persists, it rarely hampers functional results. Refracture ◦ removal of the rod after union is not recommended until skeletal maturity Valgus ankle deformity ◦ prognostic : presence of fibular insufficiency. Tibial shortening ◦ well-timed contralateral epiphysiodesis ◦ limb lengthening of the proximal tibia.
- 44. CPT is a rare but challenging case to treat Large body of evidence, but no clear definition of etiology No single method of treatment agreed upon ◦ Three established methods : intramed rod, Ilizarov frames, FVFG ◦ BMP may have a role in promoting union ◦ Taylor spatial frames and Masquelet techniques show promising results long term results? Remains a difficult case to treat (amputation?)
- 45. BENIGN FORM OF ANTEROLATERAL BOWING OF THE TIBIA never suffered a fracture, and the anterolateral bowing gradually resolved with growth Eventually the bowing in these patients remodeled and they required only management of a residual limb length discrepancy < 6 years : a one and one-half spica cast (minimal rotational stress) replaced with a long-leg cast after 6 to 8 weeks, discontinued after approximately 4 months. Older children are treated with long-leg casts : 4 months. Once cast protection is discontinued a custom- fabricated KAFO with a locked ankle joint and free
- 46. Congenital Posteromedial Bowing of the Tibia natural history of the bowing is spontaneous resolution, especially during the first 6 months nondysplastic condition with no increased risk for fracture or pseudarthrosis. Shortening, however, commonly exceeds 2.5 cm and averages 13% of total limb length Initial treatment of a newborn gentle stretching of the dorsiflexion contracture, stretching of the lateral ankle structures into a supinated or inverted position. severe case, serial casting into plantar flexion and the use of splints or bracing to maintain position until weight bearing have been prescribed
Editor's Notes
- #4: Bowing of the diaphysis of the tibia is usually noted at birth or shortly after, and thus the term “congenital” is appropriate when describing these conditions. Because most pseudarthroses of the tibia are not present at birth, the term “congenital pseudarthrosis of the tibia” is somewhat inaccurate, and dysplasia is the preferred term
- #5: The basic pathology of CPT is a dysplasia of the bone where a failure of normal bone formation at the shaft of tibia causes segmental weakening which leads to progressive anterolateral angulation, and eventually may lead into a pathologic fracture
- #9: An article published found that in Neurofibromatosis a single copy of NF-1 gene is defective, with the other copy functional (the NF gene exist in pairs) However in CPT it was found that both copies of the gene was defective and nonfunctional the double inactivation of NF1, thought to be the basis of this disease.
- #10: This theory was tested by a group of researchers by creating a mouse model with inactivation of both copies of the NF-1 gene they found that these mice had poor healing and developed a non union at the fracture site So, this may be the genetic basis of CPT
- #18: .
- #20: This is the basic technique of intramedullary rodding, as we can see here an autologous cortical bone graft taken from the anteromedial surface of the tibia is placed around the site of non-union after resection.
- #21: Here is another option of obtaining the graft from the illiac crest, and applying it around the non-union
- #22: This article reviewed the results of intramedullary rodding for the treatment of CPT and found that most yielded good results
- #23: Another long term follow up study performed on CPT patients treated with intramedullary rodding also showed good results.
- #25: The illizarov technique is also a viable option to be used in the treatment of CPT. This is a diagram of the technique, showing the resection and compression at the pseudarthrosis site, and bone lengthening of a more proximal part of the tibia
- #27: A multicenter study performed on the members of European Pediatric Orthopedic Society (EPOS)on the treatment employed for CPT shows that the Illizarov method gained the highest rate of union with an additional achievement in correction of additional deformities
- #30: Although this method has achieved good results, the main drawback is the technical difficulties of this procedure and that it requires an extensive surgical expertise.
- #31: This table attempts to compare the three methods mentioned above, and it may be used to guide our choice of treatment
- #32: Recently there has been a growing interest in using Bone Morphogenetic Proteins to augment the healing process. The two types of BMP which have been studied are rh-BMP2 and Rh-BMP7
- #33: This is a method of applying BMP to augment the healing of CPT. Here we can see the resection of the pseudarthrosis site, and subsequent fixation with an intramedullary rod passed through the ankle joint.
- #34: After compressing the site and achieving fixation, the BMP is applied to the site by using BMP-2 soaked bovine collagen sponge wrapped through the site.
- #35: This study reported the results of BMP-2 usage in the treatment of CPT, here they found that the reults were good with a faster union achieved.
- #36: Another method of augmenting bone healing to achieve union is by using periosteal grafting. In this technique, after resection of the pseudarthrosis and compression of the site, fixation using intramedullary rod and external ring fixation (Illizarov), a sheet of periosteum taken from the illiac crest is grafted around the site and added by corticocancellous bone graft
- #37: Here is a diagram of the technique emplyed
- #38: Here we can see the method employed together with a bone lengthening procedure.
- #39: As an alternative the the external fixator, the Taylor Splatial Frame may also be used. These frames are considered advantageous because it is easier to achieve multiplanar correction of deformities
- #40: These authors reported a case of CPT which have failed previous multiple surgeries which they treated using the Taylor Spatial Frame. They reported good result obtained.
- #41: Another option we can consider is using the Masquelet technique. In this technique, which was originally used to treat a long bone defect, after resection of the pseudarthrosis, a intramedullary wire is passed connecting the proximal fragment to the distal fragment spanning the gap, and then bone cement is molded around the fixated wire
- #42: Here is the method employed. After application of the bone cement, a period of time is allowed in order to allow the formation of a pseudomembreanearound the structure. Then on the next surgery the cement carefully leaving the pseudomembrane. Then the defect is filled by bone graft
- #43: Follow up at two years have shown good results