Original Article Yonsei Med J 2015 Nov;56(6):1656-1662 http://dx.doi.org/10.3349/ymj.2015.56.6.1656
pISSN: 0513-5796 · eISSN: 1976-2437
Limb Lengthening in Patients with Achondroplasia Kwang-Won Park, Rey-an Niño Garcia, Chastity Amor Rejuso, Jung-Woo Choi, and Hae-Ryong Song Institute for Rare Diseases and Department of Orthopedic Surgery, Korea University Medical Center, Guro Hospital, Seoul, Korea.
Purpose: Although bilateral lower-limb lengthening has been performed on patients with achondroplasia, the outcomes for the tibia and femur in terms of radiographic parameters, clinical results, and complications have not been compared with each other. We proposed 1) to compare the radiological outcomes of femoral and tibial lengthening and 2) to investigate the differences of complications related to lengthening. Materials and Methods: We retrospectively reviewed 28 patients (average age, 14 years 4 months) with achondroplasia who underwent bilateral limb lengthening between 2004 and 2012. All patients first underwent bilateral tibial lengthening, and at 9–48 months (average, 17.8 months) after this procedure, bilateral femoral lengthening was performed. We analyzed the pixel value ratio (PVR) and characteristics of the callus of the lengthened area on serial radiographs. The external fixation index (EFI) and healing index (HI) were computed to compare tibial and femoral lengthening. The complications related to lengthening were assessed. Results: The average gain in length was 8.4 cm for the femur and 9.8 cm for the tibia. The PVR, EFI, and HI of the tibia were significantly better than those of the femur. Fewer complications were found during the lengthening of the tibia than during the lengthening of the femur. Conclusion: Tibial lengthening had a significantly lower complication rate and a higher callus formation rate than femoral lengthening. Our findings suggest that bilateral limb lengthening (tibia, followed by femur) remains a reasonable option; however, we should be more cautious when performing femoral lengthening in selected patients. Key Words: Achondroplasia, bone lengthening
INTRODUCTION Achondroplasia is the most common form of rhizomelic dwarfism, with an incidence of approximately 1 in 25000 people.1-4 Bilateral lower-limb lengthening has been commonly performed for patients with achondroplasia, as it improves the quality of life (QOL) in selected patients.2 However, only a small number of reports have described bilateral lengthening of both the femur and tibia in these patients.5-7 Moreover, these and other previous studies analyzed the femur and tibia as a Received: September 15, 2014 Revised: January 14, 2015 Accepted: February 24, 2015 Corresponding author: Dr. Hae-Ryong Song, Institute for Rare Diseases and Department of Orthopedic Surgery, Korea University Medical Center, Guro Hospital, 148 Gurodong-ro, Guro-gu, Seoul 08308, Korea. Tel: 82-2-2626-3086, Fax: 82-2-2626-1164, E-mail: [email protected] •The authors have no financial conflicts of interest. © Copyright: Yonsei University College of Medicine 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
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whole, and these bones were not compared with each other in terms of the proportion of each limb segment and the rates of callus formation, consolidation, and complications.2,4,6,8-10 Therefore, we proposed 1) to compare the radiological outcomes of femoral and tibial lengthening and 2) to investigate the differences of complications related with bilateral lowerlimb lengthening in patients with achondroplasia.
MATERIALS AND METHODS After receiving approval from the Institutional Review Board of our hospital, we retrospectively reviewed 142 patients with achondroplasia who underwent lengthening procedures between January 2004 and December 2012. All patients were diagnosed with achondroplasia as proven by genetic evaluation. The clinical features and radiographic findings were examined by pediatric orthopedic surgeons and musculoskeletal radiologists. Any patient with achondroplasia who had joint pain related to abnormal limb alignment and functional deficit (including gait impairment) and who was willing to underwww.eymj.org
Kwang-Won Park, et al.
go surgery for limb lengthening for psychological or cosmetic reasons was eligible for the surgery. Patients who had previous injuries or bony surgery involving the lower extremities, medical comorbidities (e.g., heart disease, restrictive or obstructive lung diseases, neurologic issues such as cervicomedullary compression) that could render the patient at high risk for surgery, or other systemic diseases were excluded. Ultimately, 28 patients (112 segments; 56 femora and 56 tibias) who underwent bilateral tibial lengthening with an Ilizarov ring fixator and bilateral femoral lengthening with a monolateral external fixator were included in this study. Our goals of surgery were to realign the mechanical axis and to lengthen of bone segment by more than 30% of its initial length. The average ages of the patients at tibial and femoral lengthening surgeries were 9.2 years (range, 5.5–20.3 years) and 10.8 years (range, 6.8– 21.5 years), respectively. The study population consisted of 10 males and 18 females. All patients first underwent bilateral tibial lengthening, and 9–48 months (average, 17.8 months) after this procedure, bilateral femoral lengthening was performed. The minimum follow-up period was 1 year after the femoral lengthening surgery (average, 3.8 years; range, 1.3–6.8 years). All data were obtained from medical records and radiographs.
from 3 days after the surgery, and lengthening was started after 7 days at a rate of 1 mm/day (0.25 mm every 6 hours). For tibial bone segments with bifocal osteotomies, lengthening was performed on the proximal metaphyseal area. The rate was adjusted during follow-up according to the morphologic features of the callus as described by Li, et al.11 Rotational deformities were gradually corrected at the end of the lengthening period. We removed the fixator when we observed three continuous cortices on the radiographs, and we also based our decision on the serial pixel value ratios (PVRs) as previously described.12 Patients underwent supervised daily physiotherapy, including active and passive range of motion (ROM) of the knee and ankle, beginning 2 days after surgery. Patients were followed on a weekly basis for the first month, bi-weekly during the lengthening period, and then monthly during the consolidation period.
Radiographic evaluation Standard radiographs of both lower limbs were taken at each follow-up visit and compared with the preoperative and immediate postoperative images. All radiographs were studied by three independent observers (KWP, RNG, CAR) using Star PACS PiView (Star 5.0.6.1 software, Infinitt Co. Ltd., Seoul, Korea). At the time of each visit, we measured the amount of
Operative technique All surgeries were performed by the senior author (HRS). At the time of the initial visit, all patients showed short stature (
pISSN: 0513-5796 · eISSN: 1976-2437
Limb Lengthening in Patients with Achondroplasia Kwang-Won Park, Rey-an Niño Garcia, Chastity Amor Rejuso, Jung-Woo Choi, and Hae-Ryong Song Institute for Rare Diseases and Department of Orthopedic Surgery, Korea University Medical Center, Guro Hospital, Seoul, Korea.
Purpose: Although bilateral lower-limb lengthening has been performed on patients with achondroplasia, the outcomes for the tibia and femur in terms of radiographic parameters, clinical results, and complications have not been compared with each other. We proposed 1) to compare the radiological outcomes of femoral and tibial lengthening and 2) to investigate the differences of complications related to lengthening. Materials and Methods: We retrospectively reviewed 28 patients (average age, 14 years 4 months) with achondroplasia who underwent bilateral limb lengthening between 2004 and 2012. All patients first underwent bilateral tibial lengthening, and at 9–48 months (average, 17.8 months) after this procedure, bilateral femoral lengthening was performed. We analyzed the pixel value ratio (PVR) and characteristics of the callus of the lengthened area on serial radiographs. The external fixation index (EFI) and healing index (HI) were computed to compare tibial and femoral lengthening. The complications related to lengthening were assessed. Results: The average gain in length was 8.4 cm for the femur and 9.8 cm for the tibia. The PVR, EFI, and HI of the tibia were significantly better than those of the femur. Fewer complications were found during the lengthening of the tibia than during the lengthening of the femur. Conclusion: Tibial lengthening had a significantly lower complication rate and a higher callus formation rate than femoral lengthening. Our findings suggest that bilateral limb lengthening (tibia, followed by femur) remains a reasonable option; however, we should be more cautious when performing femoral lengthening in selected patients. Key Words: Achondroplasia, bone lengthening
INTRODUCTION Achondroplasia is the most common form of rhizomelic dwarfism, with an incidence of approximately 1 in 25000 people.1-4 Bilateral lower-limb lengthening has been commonly performed for patients with achondroplasia, as it improves the quality of life (QOL) in selected patients.2 However, only a small number of reports have described bilateral lengthening of both the femur and tibia in these patients.5-7 Moreover, these and other previous studies analyzed the femur and tibia as a Received: September 15, 2014 Revised: January 14, 2015 Accepted: February 24, 2015 Corresponding author: Dr. Hae-Ryong Song, Institute for Rare Diseases and Department of Orthopedic Surgery, Korea University Medical Center, Guro Hospital, 148 Gurodong-ro, Guro-gu, Seoul 08308, Korea. Tel: 82-2-2626-3086, Fax: 82-2-2626-1164, E-mail: [email protected] •The authors have no financial conflicts of interest. © Copyright: Yonsei University College of Medicine 2015 This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/ licenses/ by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
1656
whole, and these bones were not compared with each other in terms of the proportion of each limb segment and the rates of callus formation, consolidation, and complications.2,4,6,8-10 Therefore, we proposed 1) to compare the radiological outcomes of femoral and tibial lengthening and 2) to investigate the differences of complications related with bilateral lowerlimb lengthening in patients with achondroplasia.
MATERIALS AND METHODS After receiving approval from the Institutional Review Board of our hospital, we retrospectively reviewed 142 patients with achondroplasia who underwent lengthening procedures between January 2004 and December 2012. All patients were diagnosed with achondroplasia as proven by genetic evaluation. The clinical features and radiographic findings were examined by pediatric orthopedic surgeons and musculoskeletal radiologists. Any patient with achondroplasia who had joint pain related to abnormal limb alignment and functional deficit (including gait impairment) and who was willing to underwww.eymj.org
Kwang-Won Park, et al.
go surgery for limb lengthening for psychological or cosmetic reasons was eligible for the surgery. Patients who had previous injuries or bony surgery involving the lower extremities, medical comorbidities (e.g., heart disease, restrictive or obstructive lung diseases, neurologic issues such as cervicomedullary compression) that could render the patient at high risk for surgery, or other systemic diseases were excluded. Ultimately, 28 patients (112 segments; 56 femora and 56 tibias) who underwent bilateral tibial lengthening with an Ilizarov ring fixator and bilateral femoral lengthening with a monolateral external fixator were included in this study. Our goals of surgery were to realign the mechanical axis and to lengthen of bone segment by more than 30% of its initial length. The average ages of the patients at tibial and femoral lengthening surgeries were 9.2 years (range, 5.5–20.3 years) and 10.8 years (range, 6.8– 21.5 years), respectively. The study population consisted of 10 males and 18 females. All patients first underwent bilateral tibial lengthening, and 9–48 months (average, 17.8 months) after this procedure, bilateral femoral lengthening was performed. The minimum follow-up period was 1 year after the femoral lengthening surgery (average, 3.8 years; range, 1.3–6.8 years). All data were obtained from medical records and radiographs.
from 3 days after the surgery, and lengthening was started after 7 days at a rate of 1 mm/day (0.25 mm every 6 hours). For tibial bone segments with bifocal osteotomies, lengthening was performed on the proximal metaphyseal area. The rate was adjusted during follow-up according to the morphologic features of the callus as described by Li, et al.11 Rotational deformities were gradually corrected at the end of the lengthening period. We removed the fixator when we observed three continuous cortices on the radiographs, and we also based our decision on the serial pixel value ratios (PVRs) as previously described.12 Patients underwent supervised daily physiotherapy, including active and passive range of motion (ROM) of the knee and ankle, beginning 2 days after surgery. Patients were followed on a weekly basis for the first month, bi-weekly during the lengthening period, and then monthly during the consolidation period.
Radiographic evaluation Standard radiographs of both lower limbs were taken at each follow-up visit and compared with the preoperative and immediate postoperative images. All radiographs were studied by three independent observers (KWP, RNG, CAR) using Star PACS PiView (Star 5.0.6.1 software, Infinitt Co. Ltd., Seoul, Korea). At the time of each visit, we measured the amount of
Operative technique All surgeries were performed by the senior author (HRS). At the time of the initial visit, all patients showed short stature (
