Case report 507
Physeal bar equivalent Hamlet A. Peterson, William J. Shaughnessy and Anthony A. Stans Premature partial physeal arrest without the formation of an osseous bar – physeal bar equivalent (PBE) – is uncommon. Four children with a PBE had an infection near the distal femoral physis before the age of 11 months. Some growth was achieved after resection of the PBE in each case. Of two cases diagnosed and treated early, one required only contralateral physeal arrests to achieve limb-length equality at maturity. The other, currently 8 years and 4 months old, has a 1.1-cm limb-length discrepancy 6 years after PBE resection and will require observation until maturity. Of two cases diagnosed and treated late, one required ipsilateral femoral lengthening and contralateral femoral shortening and physeal arrests to treat the limb-length discrepancy and angular deformity. The other, currently 7 years and 1 month
Introduction A physeal bar is a variably sized bridge of bone from the metaphysis across the physis to the epiphysis and is also known as premature partial physeal arrest or closure. The osseous bar tethers the growth of the remaining normal physis, which results in deformities of the metaphysis, physis, and epiphysis, relative shortening of the involved bone, and angular deformity of the limb if the bar is eccentric. A physeal bar equivalent (PBE) is the result of physeal cell death in a portion of the physis, which produces similar tethering deformities of the metaphysis, physis, and epiphysis and similar relative shortening and angular deformity of the bone, but has no bar of bone across the physis. Alternative names for this condition could be ‘forme fruste physeal bar’, ‘pseudophyseal bar’, a ‘radiographically invisible physeal bar’, or ‘a physeal bar that is not’. Here, we present four cases that fit the above description of PBE. All involved the distal femoral physis and were associated with osteomyelitis of the distal femur and/or septic arthritis of the knee in children younger than 11 months. Staphylococcus aureus was cultured initially in all four cases. In two cases (1 and 2), the PBE was excised and replaced by an interposition material before the relative shortening reached 2 cm and before angular deformity developed, with resumption of normal growth and excellent clinical results. In the other two cases (3 and 4), surgical excision of the PBE was performed late, which resulted in valuable growth, but required (or will require) limb-length or angular correction surgery or both. Cases 1 and 3 have completed growth; cases 2 and 4 remain under observation (Table 1). 1060-152X Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
old, has a 4.8-cm discrepancy and will need future surgical limb-length equalization. Early recognition and treatment of PBE is required to avoid severe limb-length inequality and angular deformity. J Pediatr Orthop B 26:507–514 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. Journal of Pediatric Orthopaedics B 2017, 26:507–514 Keywords: distal femur, osteomyelitis, physeal bar, physeal bar equivalent, physis, septic arthritis Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA Correspondence to Hamlet A. Peterson, MD, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA Tel: + 1 507 284 2691; e-mail: [email protected]
The purpose in presenting these cases is to show that, early in life, growth from a portion of the physis may be irrevocably damaged without the formation of a physeal bone bar and that treatment by early excision of the damaged portion of the physis and insertion of an interposition material may allow the remaining physis to resume longitudinal growth. Early treatment and close follow-up, of both the initial infection and the PBE, can decrease sequelae requiring reconstructive surgery.
Case series Case 1
An infant boy was born prematurely (gestational age not known) weighing 1300 g. He was transferred to a tertiary care hospital, intubated, supported with a ventilator, and had an umbilical artery catheter inserted. Ampicillin and cefotaxime were administered intravenously for 7 days. At age 5 weeks, his right knee was swollen and tender; radiography showed moderate soft-tissue swelling of the right knee. The distal femoral epiphyseal ossification center (EOC) was not yet radiographically visible. Cultures of blood, right knee joint fluid, and distal right femoral bone aspiration all grew S. aureus. After antibiotic treatment, the knee swelling subsided and a bone scan at 6 weeks of age was negative for focal uptake. He was dismissed from the hospital at the age of 3 months with a diagnosis of septic arthritis of the right knee. At the age of 2 years and 5 months, a scanogram showed the right femur to be 1.2 cm shorter than the left, with medial bowing of the mid and distal femur and 20° of genu varum (Fig. 1a). The medial metaphysis, physis, and epiphysis were abnormally irregular. Two months later, an anterior–posterior computed tomography image DOI: 10.1097/BPB.0000000000000384
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showed sclerosis, irregularity, and slanting of the medial metaphysis and fragmentation of the medial EOC (Fig. 1b). The lateral view confirmed considerable deformity of the physis, but no physeal bar. At the age of 2 years and 7 months, the proximal tip of the abnormal area was excised, as a physeal bar would be excised [1,2], and the cavity filled with cranioplast (Fig. 1c). Titanium break-off wires were placed parallel in the metaphysis and epiphysis 2.7 cm apart. Scanograms at 6-month intervals showed continued good growth, until the age of 14 years, when the distal right femoral growth slowed. Elective surgical physeal arrests were performed on the normal left distal femur and proximal tibia at the age of 14 years and 1 month.
c
b
–0.1 –1.1a –3.4 –4.8a 16 + 0 8+4 18 + 0 7+1 No Pending Yes Pending
12.5 12.3
Age at last follow-up (year + months) PBE recurred or physeal bar developed
Amount of growth from PBE excision (cm)
Residual total leglength inequality (cm)
Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
The most recent scanogram, at the age of 16 years (Fig. 1d), shows the metal markers 15.2 cm apart, a total leg-length difference of 0.1 cm (shorter on the right), and all physes closed. After excision of the PBE, the distal right femoral physis grew 12.5 cm and the 20° varus deformity corrected spontaneously (from Peterson [3], used with permission and additional follow-up).
EOC, epiphyseal ossification center; PBE, physeal bar equivalent. a Case still in progress. b Data unavailable (no record of distance between metal markers at the time of PBE excision). c Undeterminable, no metal markers used.
No No Yes Yes No No Yes Yes 5 weeks 10 months 5 months 12 days
Case/sex
1/male 2/female 3/female 4/female
5 6 2 3 2, 1, 3, 3, 2+7 2+4 3+7 3+5
Disappearance of distal femur EOC Angular correcting osteotomy Time from infection to PBE excision (year, months) Age at PBE excision (year + months) Age at infection
Patient characteristics
Case 2
Table 1
508
A 10-month-old girl was considered to have ‘a viral prodromal upper respiratory infection’. She stopped crawling and standing. A radiograph of the left knee was normal. She had an intermittent fever, which reached a maximum of 100.2°F. Only ‘anti-inflammatory’ medication was administered. At the first orthopedic examination 7 days later, radiography findings (Fig. 2a) were reported to be normal, but a loss of bone architecture was observed in the lateral metaphysis and epiphysis (arrows). Laboratory tests showed a white blood cell count of 16.4 × 109/l, a sedimentation rate of 30 mm/h, and a C-reactive protein level of 0.8 mg/l. She was admitted to the hospital with suspected septic arthritis of the left knee. Culture of aspirated knee fluid grew S. aureus sensitive to methicillin. MRI performed 2 days after radiography (Fig. 2b) showed an abnormality consistent with osteomyelitis in the metaphysis, physis, and cartilaginous portion of the epiphysis, but not the EOC. The same day, curettage of the lesion was performed through a window in the lateral metaphyseal cortex. The curette crossed the physis into the epiphysis. The osteomyelitis was eradicated successfully. At the age of 2 years and 3 months, the femur was growing, with 30° genu valgum. Computed tomography at that time showed persistent physeal abnormality, but no osseous bar (Fig. 2c). Curettage of the PBE was performed again at the age of 2 years and 4 months. Histologic analysis indicated ‘fibrous tissue’ at the apex of the defect, without any physeal tissue. Fat taken from the buttock was inserted into the cavity as an interposition material. A titanium break-off wire was inserted into the metaphysis. Residual genu valgum (10°) noted at the
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Physeal bar equivalent Peterson et al. 509
Fig. 1
(a)
(b)
2+5
2+7
(c)
(d)
2+7 16 + 0 44.5
46.5
15.2
42.3
40.4
Case 1: (a) scanogram at the age of 2 years and 5 months showing right femoral relative shortening and bowing, along with metaphyseal, physeal, and epiphyseal abnormalities; (b) two computed tomography views showing physeal irregularity and continuity, but no physeal bar; (c) 3 weeks after physeal bar equivalent excision, the metal markers are 2.7 cm apart; (d) at the age of 16 years and 0 months, the metal markers were 15.2 cm apart (arrows), the femora were straight, and all physes were closed.
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510 Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
Fig. 2
(a)
(b)
0 + 10
0 + 10
(c)
(d) 8+4
36.2
35.1
12.3
2+3
Case 2: (a) lytic defect in the lateral distal femoral metaphysis, physis, and epiphysis marked by arrows; (b) MRI showing abnormality in the lateral distal femoral metaphysis, physis, and epiphysis; (c) computed tomography image at the age of 2 years and 3 months showing an elongated lytic lesion in the lateral metaphysis documenting longitudinal growth after physeal bar equivalent resection; (d) by the age of 8 years and 4 months, the proximal metal marker was 12.3 cm from the physis (arrows).
age of 6 years and 7 months led to the insertion of an eight-plate over the medial side of the distal femoral physis, which was removed at the age of 7 years and 11 months. At last follow-up (age 8 years and 4 months), the physis was 12.3 cm from the metal marker (now in the diaphysis), the knee angle was normal, and the patient was normally active and asymptomatic (Fig. 2) (from
Peterson [3], used with permission and additional followup). Case 3
At the age of 5 months, an infant girl was administered amoxicillin for an upper respiratory tract infection. Six days later, she was hospitalized with a temperature of
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Physeal bar equivalent Peterson et al. 511
Fig. 3
(a)
(b)
(c) 0 + 11
0+7
MF 1.50
R 0 + 11 (d)
(e) 18 + 4 38.4
2+7
36.6
42.0
36.4
Case 3: (a) distal femoral mild physeal cupping; (b) at the age of 11 months, the distal femoral epiphyseal ossification center (EOC) had radiographically disappeared; (c) MRI showing an irregular physis, but no physeal bar or EOC on the right distal femur (left image); (d) at the age of 2 years and 7 months, the EOC had reappeared and was bifid. The central portion of the physis was not growing. Physeal bar equivalent excision was performed at the age of 3 years and 7 months; (e) at the age of 18 years and 4 months, after extensive surgery on both lower extremities, the patient was walking comfortably, but with residual 3.4-cm right lower extremity shortening.
105°F and swelling and erythema of the right knee. Three days later, the right knee was aspirated, followed by arthrotomy and synovectomy. Cultures grew S. aureus and Gram-positive enterococci. The patient was administered nafcillin, followed by cefaclor. Sixteen days later, signs of increased right knee pain prompted readmission. Blood cultures at this time were negative. Ampicillin/ sulbactam, rifampin, and gentamicin were administered. At the age of 7 months, radiography showed mild physeal cupping of the distal femoral physis (Fig. 3a). T2 MRI showed reactive nonspecific edema in the metaphysis and surrounding tissue and widening of the physis. At the age of 11 months, the EOC had disappeared radiographically (Fig. 3b). T1 MRI showed focal marrow fat replacement in the distal central metaphysis extending across the physis into the now-unossified epiphysis (Fig. 3c).
At the age of 2 years and 7 months, the femoral lengths were equal, but there was 30° of right genu valgum (Fig. 3d). The epiphysis had partially reossified in a bifid manner and the physeal cupping was increased, but there was no physeal bar. At the age of 3 years and 7 months, the PBE was excised and vascular clips were inserted as markers. Growth resumed for some time before the bar recurred. Open wedge distal femoral osteotomy was performed at the age of 7 years and 3 months. At the age of 10 years and 3 months, the distance between the metal markers confirmed that some growth occurred after the PBE excision, but the physis was now closed. Right femoral lengthening incorporating two flexible intramedullary metal rods (Synthes, West Chester, Pennsylvania, USA) was performed, but was followed by lateral dislocation of the patella and marked loss of knee motion. At the age of 16 years and 0 months, her leg-length discrepancy was accompanied by right knee instability and
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giving way, as well as right leg and low back pain. A standing radiograph showed the right lower extremity to be ∼ 6 cm shorter than the left and all physes closed. At the age of 17 years and 0 months, the flexible Synthes rods were removed, accompanied by a varus/extension osteotomy fixed with a Synthes 95° blade plate and open reduction of the patella with proximal and distal extensor mechanism realignment, including tibial tubercle transfer medially. At the age of 18 years and 0 months, left femoral shortening was performed and fixed with an intramedullary nail. At last follow-up (age 18 years and 4 months), the patient was walking comfortably, with the right lower extremity 3.4 cm shorter than the left (Fig. 3e) (from Peterson [3], used with permission and additional follow-up). Case 4
A biplacental twin girl was born by cesarean delivery at 29 weeks’ gestation. She was supported with a ventilator for 8 days after birth. At 10 days old, the left knee was swollen. She was first evaluated by an orthopedist at 12 days; arthrocentesis of the knee yielded cloudy fluid with 120 × 109/l white blood cells, with 98% segmented neutrophils. The knee was irrigated with normal saline and cefazolin was started. Both blood and knee fluids were positive for methicillin-sensitive S. aureus. After knee reaspiration and reirrigation 8 h later, the white blood cell count was 33 × 109/l, with 95% segmented neutrophils. After ten hours, the knee was aspirated a third time, with similar results. After four hours, open incision and drainage (I&D) was performed, including placement of ingress/egress tubes. The system failed after 12 h, resulting in repeat I&D. Two days later, another I&D included placement of Penrose drains, which were removed at the bedside 4 days later. At the age of 16 days, the distal femoral EOC was faintly visible radiographically. From the 16th to the 28th day, the neonatologist and anesthesiologist believed that the patient was too frail for a general anesthetic. At 28 days, new metaphyseal subperiosteal bone was forming, which indicated healing osteomyelitis. On the 29th day, arthrotomy confirmed a detached, posteriorly displaced, mobile epiphysis, which was reduced and stabilized temporarily with crossed Kirschner wires. Antibiotics were continued for 6 weeks, well after the complete blood count, erythrocyte sedimentation rate, and C-reactive protein level had returned to normal. She also had a septic right ankle with osteomyelitis of the talus treated with I&D. The patient was discharged home at 2 months of age with no further signs of infection. She began walking at the age of 13 months, at which time the left femur was 1.6 cm shorter than the right, the distal femoral metaphysis was irregularly shaped and irregularly ossified, and there was no ossification in the distal femoral epiphysis (Fig. 4a). At the age of 3 years and 4 months, the patient was walking with a shoe lift
(Fig. 4b). There was 45° of genu valgum. At the age of 3 years and 5 months, the apex of the central physeal arrest was excised by direct vision through a transverse osteotomy of the distal femoral metaphysis. The surgeon noted a thin line of normal white physeal cartilage circumferentially in the cavity. The cavity was lined with bone wax and filled with fat. After correcting the valgus deformity, the osteotomy was fixed with crossed Kirschner wires. No metal markers were inserted. At last follow-up, at the age of 7 years and 1 month, 3 years and 9 months after PBE excision, the distal femur was growing with continuing bifid ossification of the epiphysis (Fig. 4c). The left femur was 4.8 cm shorter than the right, but because of relative overgrowth of the left tibia, the left lower extremity was only 3.2 cm shorter than the right. Although the PBE excision was useful in re-establishing growth, this patient will require follow-up until maturity. Early premature, spontaneous, complete arrest of the distal left femoral physis can be expected, requiring major limb-equalization procedures, as in case 3 (case contributed by Dr Richard Munk, Toledo, Ohio, USA, with permission).
Discussion At birth, and for a variable time thereafter, most epiphyses have no ossification center. The distal femur is the only epiphysis that typically, but not always, has an ossification center at birth. Before the development of an EOC, injury to the physis can cause premature partial physeal death, without development of an osseous bar (a PBE). The same result can occur with an immature EOC surrounded by abundant hyaline cartilage, which makes it relatively difficult for a bone bar to develop from the metaphysis to the EOC. Features present in each case of PBE reported here include (a) septic arthritis of a knee joint and/or osteomyelitis of the distal femur in a child younger than 11 months; (b) an absent or immature distal femoral EOC; (c) death of a portion of the distal femoral physis in or near the center of the physis; (d) subsequent deformity of the metaphysis, physis, and epiphysis; (e) impaired longitudinal femoral growth with angular deformity; and (f) no radiographically identifiable osseous bar from metaphysis to epiphysis. Metaphyseal osteomyelitis and septic arthritis often coexist at the time of presentation (as they apparently did in these four cases), and it may be impossible to determine which came first. Septic arthritis may be a byproduct of a nidus of metaphyseal osteomyelitis that has infiltrated the joint and spread through the epiphyseal vessels into the epiphysis and then to the physis. Although S. aureus was cultured in all four cases, it seems likely that the same condition could result from infectious organisms other than S. aureus.
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Physeal bar equivalent Peterson et al. 513
Fig. 4
(a)
(b)
(c) 3+4
1+1
12.5 14.1
11.6 11.6
Case 4: (a) 1 year postoperatively, the left epiphyseal ossification center was absent radiographically; (b) at the age of 3 years and 4 months, the patient was walking with a left shoe lift; (c) at the age of 7 years and 1 month, the left femur was growing well. The physis was open and the epiphysis had reossified but was bifid.
Radiographic disappearance and subsequent reappearance of the EOC, as noted in cases 3 and 4, occurred months after the original acute infection and has been discussed previously with illustrations and references [3–5]. The fact that epiphyseal cartilage can reconstitute a new EOC suggests that reparative hyper-revascularization is responsible for the radiographic disappearance of the ossification center rather than enzymatic dissolution of bone by the infecting organism [4]. The reossified EOC may be small, bifid, or irregular [5], with consequent epiphyseal deformity. PBE excision provided some growth in each case. In case 1, the involved physis grew as well as its normal contralateral counterpart for 12 years after PBE excision, but closed before the other three uninjured major knee physes. Thus, contralateral surgical physeal arrests were used to prevent additional limb-length discrepancy and to improve it as the patient completed growth. This excellent result was because of early recognition and treatment of the PBE. PBE excision re-established growth in case 3, but the physis closed completely before maturity. PBE excision re-established growth in cases 2 and 4, and their outcome is still pending. These patients need careful follow-up because their involved physis is anticipated to also close early, near maturity or sooner.
In case 1 in this patient series, 20° angular deformity corrected spontaneously to normal by PBE alone. Case 2 had 30° of angular deformity, corrected partially by PBE excision, and was definitively treated with an eight-plate (tension band plate). Cases 3 and 4 had more than 30° angular deformity and were treated with corrective osteotomy. Additional reported sites of the same PBE phenomena include the distal humerus, where it is referred to as the fishtail deformity [6–9], long bone physes in some newborns with intrauterine vascular deficiency [10–15], and the proximal femoral physis of children born prematurely, with neonatal S. aureus hip infection [16]. Treatment
For the cases reported here, early diagnosis and treatment of both the initial infection and the resulting growth arrest were the keys to a successful outcome (Table 1). The management of acute infection near a physis, whether intraosseous or intra-articular, is a race against time. Delays in the diagnosis or institution of care are the most important factors affecting outcome [17–20]. The only emergency orthopedic surgery necessary in children, other than for trauma, is for acute osteomyelitis near a physis or acute septic arthritis. Patients who seek care late in the evening or in early morning hours should go to surgery immediately, without waiting for the morning. The interplay between bone or joint aspiration, aspiration
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514 Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
and lavage, repeated aspiration, continuous irrigation, I&D, packing the wound open, and the role and choice of antibiotics can all be debated, but every hour that an acute suppurative process continues untreated near a physis is of urgent significance and will negatively affect the ultimate outcome.
Conflicts of interest
There are no conflicts of interest.
References 1
Similarly, once a PBE deformity is identified, the sooner the area of the deficient physis is removed and replaced by an interposition material, the better the result (case 1). This requires close follow-up after the infection and close long-term follow-up after PBE excision as physeal closure can reoccur at any time and be partial or complete (case 3), most predictably near completion of growth. Indications for PBE excision surgery include a progressive bonelength discrepancy or angular deformity. Surgery should not be performed in the absence of such deformity. In this case series, the two patients (cases 1 and 2) who had the PBE removed and replaced by an interposition material within 2 and a half years of infection resumed normal growth and required only contralateral surgical physeal arrests to achieve acceptable leg-length equality (Table 1). In the other two cases (3 and 4), although surgical removal of the PBE resulted in the resumption of valuable growth, the loss of growth and angular deformity were too great to be fully corrected by bar excision alone, and reconstructive surgery was performed or will be needed.
2 3 4 5
6
7
8
9 10 11 12
Summary
This case series has defined and illustrated the PBE. All four cases were characterized by infection near the distal femoral physis in a child younger than 11 months of age. This resulted in the death of the involved portion of the physeal cells and produced metaphyseal, physeal, and epiphyseal deformities similar to those observed with a typical physeal bar, but without the bone bar from metaphysis to epiphysis. Two cases treated with early PBE excision required less reconstructive surgery.
13
14 15 16
17 18
Acknowledgements Portions of cases 1, 2, and 3 were previously published in Peterson [3]. Used with permission of Mayo Foundation for Medical Education and Research.
19 20
Peterson HA. Partial growth plate arrest and its treatment. J Pediatr Orthop 1984; 4:246–258. Peterson HA. Epiphyseal growth plate fractures. Heidelberg, Germany: Springer; 2007. Peterson HA. Physeal injury other than fracture. Heidelberg, Germany: Springer; 2012. Wood BP. The vanishing epiphyseal ossification center: a sequel to septic arthritis of childhood. Radiology 1980; 134:387–389. Jaimes C, Chauvin NA, Delgado J, Jaramillo D. MR imaging of normal epiphyseal development and common epiphyseal disorders. Radiographics 2014; 34:449–471. Yang Z, Wang Y, Gilula LA, Yamaguchi K. Microcirculation of the distal humeral epiphyseal cartilage: implications for post-traumatic growth deformities. J Hand Surg Am 1998; 23:165–172. Nwakama AC, Peterson HA, Shaughnessy WJ. Fishtail deformity following fracture of the distal humerus in children: historical review, case presentations, discussion of etiology, and thoughts on treatment. J Pediatr Orthop B 2000; 9:309–318. Schulte DW, Ramseier LE. Fishtail deformity as a result of a non-displaced supracondylar fracture of the humerus. Acta Orthop Belg 2009; 75:408–410. Glotzbecker MP, Bae DS, Links AC, Waters PM. Fishtail deformity of the distal humerus: a report of 15 cases. J Pediatr Orthop 2013; 33:592–597. Armstrong AP, Page RE. Intrauterine vascular deficiency of the upper limb. J Hand Surg Br 1997; 22:607–611. Carr MM, al-Qattan M, Clarke HM. Extremity gangrene in utero. J Hand Surg Br 1996; 21:652–655. Gosain AK, Moore FO, Rabinowitz LG. Congenital pressure necrosis of the forearm in a newborn infant. Ann Plast Surg 2000; 45:318–322. (discussion 322–328). Ragland R, Moukoko D, Ezaki M, Carter PR, Mills J. Forearm compartment syndrome in the newborn: report of 24 cases. J Hand Surg Am 2005; 30:997–1003. Silfen R, Amir A, Sirota L, Hauben DJ. Congenital Volkmann–Lesser ischemic contracture of the upper limb. Ann Plast Surg 2000; 45:313–317. Tsujino A, Hooper G. Neonatal compression ischaemia of the forearm. J Hand Surg Br 1997; 22:612–614. Song HR, Oh CW, Guille JT, Song KS, Kyung HS, Kim SY, Park BC. Lateral growth disturbance of the proximal femur in premature infants who had neonatal sepsis. J Pediatr Orthop B 2006; 15:178–182. Paterson DC. Acute suppurative arthritis in infancy and childhood. J Bone Joint Surg Br 1970; 52:474–482. Gillespie R. Septic arthritis of childhood. Clin Orthop Relat Res 1973; 96:152–159. Morrey BF, Bianco AJ Jr, Rhodes KH. Septic arthritis in children. Orthop Clin North Am 1975; 6:923–934. Nade S, Nade S, Nade S. Acute septic arthritis in infancy and childhood. J Bone Joint Surg Br 1983; 65:234–241.
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Physeal bar equivalent Hamlet A. Peterson, William J. Shaughnessy and Anthony A. Stans Premature partial physeal arrest without the formation of an osseous bar – physeal bar equivalent (PBE) – is uncommon. Four children with a PBE had an infection near the distal femoral physis before the age of 11 months. Some growth was achieved after resection of the PBE in each case. Of two cases diagnosed and treated early, one required only contralateral physeal arrests to achieve limb-length equality at maturity. The other, currently 8 years and 4 months old, has a 1.1-cm limb-length discrepancy 6 years after PBE resection and will require observation until maturity. Of two cases diagnosed and treated late, one required ipsilateral femoral lengthening and contralateral femoral shortening and physeal arrests to treat the limb-length discrepancy and angular deformity. The other, currently 7 years and 1 month
Introduction A physeal bar is a variably sized bridge of bone from the metaphysis across the physis to the epiphysis and is also known as premature partial physeal arrest or closure. The osseous bar tethers the growth of the remaining normal physis, which results in deformities of the metaphysis, physis, and epiphysis, relative shortening of the involved bone, and angular deformity of the limb if the bar is eccentric. A physeal bar equivalent (PBE) is the result of physeal cell death in a portion of the physis, which produces similar tethering deformities of the metaphysis, physis, and epiphysis and similar relative shortening and angular deformity of the bone, but has no bar of bone across the physis. Alternative names for this condition could be ‘forme fruste physeal bar’, ‘pseudophyseal bar’, a ‘radiographically invisible physeal bar’, or ‘a physeal bar that is not’. Here, we present four cases that fit the above description of PBE. All involved the distal femoral physis and were associated with osteomyelitis of the distal femur and/or septic arthritis of the knee in children younger than 11 months. Staphylococcus aureus was cultured initially in all four cases. In two cases (1 and 2), the PBE was excised and replaced by an interposition material before the relative shortening reached 2 cm and before angular deformity developed, with resumption of normal growth and excellent clinical results. In the other two cases (3 and 4), surgical excision of the PBE was performed late, which resulted in valuable growth, but required (or will require) limb-length or angular correction surgery or both. Cases 1 and 3 have completed growth; cases 2 and 4 remain under observation (Table 1). 1060-152X Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved.
old, has a 4.8-cm discrepancy and will need future surgical limb-length equalization. Early recognition and treatment of PBE is required to avoid severe limb-length inequality and angular deformity. J Pediatr Orthop B 26:507–514 Copyright © 2017 Wolters Kluwer Health, Inc. All rights reserved. Journal of Pediatric Orthopaedics B 2017, 26:507–514 Keywords: distal femur, osteomyelitis, physeal bar, physeal bar equivalent, physis, septic arthritis Department of Orthopedic Surgery, Mayo Clinic, Rochester, Minnesota, USA Correspondence to Hamlet A. Peterson, MD, Department of Orthopedic Surgery, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA Tel: + 1 507 284 2691; e-mail: [email protected]
The purpose in presenting these cases is to show that, early in life, growth from a portion of the physis may be irrevocably damaged without the formation of a physeal bone bar and that treatment by early excision of the damaged portion of the physis and insertion of an interposition material may allow the remaining physis to resume longitudinal growth. Early treatment and close follow-up, of both the initial infection and the PBE, can decrease sequelae requiring reconstructive surgery.
Case series Case 1
An infant boy was born prematurely (gestational age not known) weighing 1300 g. He was transferred to a tertiary care hospital, intubated, supported with a ventilator, and had an umbilical artery catheter inserted. Ampicillin and cefotaxime were administered intravenously for 7 days. At age 5 weeks, his right knee was swollen and tender; radiography showed moderate soft-tissue swelling of the right knee. The distal femoral epiphyseal ossification center (EOC) was not yet radiographically visible. Cultures of blood, right knee joint fluid, and distal right femoral bone aspiration all grew S. aureus. After antibiotic treatment, the knee swelling subsided and a bone scan at 6 weeks of age was negative for focal uptake. He was dismissed from the hospital at the age of 3 months with a diagnosis of septic arthritis of the right knee. At the age of 2 years and 5 months, a scanogram showed the right femur to be 1.2 cm shorter than the left, with medial bowing of the mid and distal femur and 20° of genu varum (Fig. 1a). The medial metaphysis, physis, and epiphysis were abnormally irregular. Two months later, an anterior–posterior computed tomography image DOI: 10.1097/BPB.0000000000000384
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showed sclerosis, irregularity, and slanting of the medial metaphysis and fragmentation of the medial EOC (Fig. 1b). The lateral view confirmed considerable deformity of the physis, but no physeal bar. At the age of 2 years and 7 months, the proximal tip of the abnormal area was excised, as a physeal bar would be excised [1,2], and the cavity filled with cranioplast (Fig. 1c). Titanium break-off wires were placed parallel in the metaphysis and epiphysis 2.7 cm apart. Scanograms at 6-month intervals showed continued good growth, until the age of 14 years, when the distal right femoral growth slowed. Elective surgical physeal arrests were performed on the normal left distal femur and proximal tibia at the age of 14 years and 1 month.
c
b
–0.1 –1.1a –3.4 –4.8a 16 + 0 8+4 18 + 0 7+1 No Pending Yes Pending
12.5 12.3
Age at last follow-up (year + months) PBE recurred or physeal bar developed
Amount of growth from PBE excision (cm)
Residual total leglength inequality (cm)
Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
The most recent scanogram, at the age of 16 years (Fig. 1d), shows the metal markers 15.2 cm apart, a total leg-length difference of 0.1 cm (shorter on the right), and all physes closed. After excision of the PBE, the distal right femoral physis grew 12.5 cm and the 20° varus deformity corrected spontaneously (from Peterson [3], used with permission and additional follow-up).
EOC, epiphyseal ossification center; PBE, physeal bar equivalent. a Case still in progress. b Data unavailable (no record of distance between metal markers at the time of PBE excision). c Undeterminable, no metal markers used.
No No Yes Yes No No Yes Yes 5 weeks 10 months 5 months 12 days
Case/sex
1/male 2/female 3/female 4/female
5 6 2 3 2, 1, 3, 3, 2+7 2+4 3+7 3+5
Disappearance of distal femur EOC Angular correcting osteotomy Time from infection to PBE excision (year, months) Age at PBE excision (year + months) Age at infection
Patient characteristics
Case 2
Table 1
508
A 10-month-old girl was considered to have ‘a viral prodromal upper respiratory infection’. She stopped crawling and standing. A radiograph of the left knee was normal. She had an intermittent fever, which reached a maximum of 100.2°F. Only ‘anti-inflammatory’ medication was administered. At the first orthopedic examination 7 days later, radiography findings (Fig. 2a) were reported to be normal, but a loss of bone architecture was observed in the lateral metaphysis and epiphysis (arrows). Laboratory tests showed a white blood cell count of 16.4 × 109/l, a sedimentation rate of 30 mm/h, and a C-reactive protein level of 0.8 mg/l. She was admitted to the hospital with suspected septic arthritis of the left knee. Culture of aspirated knee fluid grew S. aureus sensitive to methicillin. MRI performed 2 days after radiography (Fig. 2b) showed an abnormality consistent with osteomyelitis in the metaphysis, physis, and cartilaginous portion of the epiphysis, but not the EOC. The same day, curettage of the lesion was performed through a window in the lateral metaphyseal cortex. The curette crossed the physis into the epiphysis. The osteomyelitis was eradicated successfully. At the age of 2 years and 3 months, the femur was growing, with 30° genu valgum. Computed tomography at that time showed persistent physeal abnormality, but no osseous bar (Fig. 2c). Curettage of the PBE was performed again at the age of 2 years and 4 months. Histologic analysis indicated ‘fibrous tissue’ at the apex of the defect, without any physeal tissue. Fat taken from the buttock was inserted into the cavity as an interposition material. A titanium break-off wire was inserted into the metaphysis. Residual genu valgum (10°) noted at the
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Physeal bar equivalent Peterson et al. 509
Fig. 1
(a)
(b)
2+5
2+7
(c)
(d)
2+7 16 + 0 44.5
46.5
15.2
42.3
40.4
Case 1: (a) scanogram at the age of 2 years and 5 months showing right femoral relative shortening and bowing, along with metaphyseal, physeal, and epiphyseal abnormalities; (b) two computed tomography views showing physeal irregularity and continuity, but no physeal bar; (c) 3 weeks after physeal bar equivalent excision, the metal markers are 2.7 cm apart; (d) at the age of 16 years and 0 months, the metal markers were 15.2 cm apart (arrows), the femora were straight, and all physes were closed.
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510 Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
Fig. 2
(a)
(b)
0 + 10
0 + 10
(c)
(d) 8+4
36.2
35.1
12.3
2+3
Case 2: (a) lytic defect in the lateral distal femoral metaphysis, physis, and epiphysis marked by arrows; (b) MRI showing abnormality in the lateral distal femoral metaphysis, physis, and epiphysis; (c) computed tomography image at the age of 2 years and 3 months showing an elongated lytic lesion in the lateral metaphysis documenting longitudinal growth after physeal bar equivalent resection; (d) by the age of 8 years and 4 months, the proximal metal marker was 12.3 cm from the physis (arrows).
age of 6 years and 7 months led to the insertion of an eight-plate over the medial side of the distal femoral physis, which was removed at the age of 7 years and 11 months. At last follow-up (age 8 years and 4 months), the physis was 12.3 cm from the metal marker (now in the diaphysis), the knee angle was normal, and the patient was normally active and asymptomatic (Fig. 2) (from
Peterson [3], used with permission and additional followup). Case 3
At the age of 5 months, an infant girl was administered amoxicillin for an upper respiratory tract infection. Six days later, she was hospitalized with a temperature of
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Physeal bar equivalent Peterson et al. 511
Fig. 3
(a)
(b)
(c) 0 + 11
0+7
MF 1.50
R 0 + 11 (d)
(e) 18 + 4 38.4
2+7
36.6
42.0
36.4
Case 3: (a) distal femoral mild physeal cupping; (b) at the age of 11 months, the distal femoral epiphyseal ossification center (EOC) had radiographically disappeared; (c) MRI showing an irregular physis, but no physeal bar or EOC on the right distal femur (left image); (d) at the age of 2 years and 7 months, the EOC had reappeared and was bifid. The central portion of the physis was not growing. Physeal bar equivalent excision was performed at the age of 3 years and 7 months; (e) at the age of 18 years and 4 months, after extensive surgery on both lower extremities, the patient was walking comfortably, but with residual 3.4-cm right lower extremity shortening.
105°F and swelling and erythema of the right knee. Three days later, the right knee was aspirated, followed by arthrotomy and synovectomy. Cultures grew S. aureus and Gram-positive enterococci. The patient was administered nafcillin, followed by cefaclor. Sixteen days later, signs of increased right knee pain prompted readmission. Blood cultures at this time were negative. Ampicillin/ sulbactam, rifampin, and gentamicin were administered. At the age of 7 months, radiography showed mild physeal cupping of the distal femoral physis (Fig. 3a). T2 MRI showed reactive nonspecific edema in the metaphysis and surrounding tissue and widening of the physis. At the age of 11 months, the EOC had disappeared radiographically (Fig. 3b). T1 MRI showed focal marrow fat replacement in the distal central metaphysis extending across the physis into the now-unossified epiphysis (Fig. 3c).
At the age of 2 years and 7 months, the femoral lengths were equal, but there was 30° of right genu valgum (Fig. 3d). The epiphysis had partially reossified in a bifid manner and the physeal cupping was increased, but there was no physeal bar. At the age of 3 years and 7 months, the PBE was excised and vascular clips were inserted as markers. Growth resumed for some time before the bar recurred. Open wedge distal femoral osteotomy was performed at the age of 7 years and 3 months. At the age of 10 years and 3 months, the distance between the metal markers confirmed that some growth occurred after the PBE excision, but the physis was now closed. Right femoral lengthening incorporating two flexible intramedullary metal rods (Synthes, West Chester, Pennsylvania, USA) was performed, but was followed by lateral dislocation of the patella and marked loss of knee motion. At the age of 16 years and 0 months, her leg-length discrepancy was accompanied by right knee instability and
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512 Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
giving way, as well as right leg and low back pain. A standing radiograph showed the right lower extremity to be ∼ 6 cm shorter than the left and all physes closed. At the age of 17 years and 0 months, the flexible Synthes rods were removed, accompanied by a varus/extension osteotomy fixed with a Synthes 95° blade plate and open reduction of the patella with proximal and distal extensor mechanism realignment, including tibial tubercle transfer medially. At the age of 18 years and 0 months, left femoral shortening was performed and fixed with an intramedullary nail. At last follow-up (age 18 years and 4 months), the patient was walking comfortably, with the right lower extremity 3.4 cm shorter than the left (Fig. 3e) (from Peterson [3], used with permission and additional follow-up). Case 4
A biplacental twin girl was born by cesarean delivery at 29 weeks’ gestation. She was supported with a ventilator for 8 days after birth. At 10 days old, the left knee was swollen. She was first evaluated by an orthopedist at 12 days; arthrocentesis of the knee yielded cloudy fluid with 120 × 109/l white blood cells, with 98% segmented neutrophils. The knee was irrigated with normal saline and cefazolin was started. Both blood and knee fluids were positive for methicillin-sensitive S. aureus. After knee reaspiration and reirrigation 8 h later, the white blood cell count was 33 × 109/l, with 95% segmented neutrophils. After ten hours, the knee was aspirated a third time, with similar results. After four hours, open incision and drainage (I&D) was performed, including placement of ingress/egress tubes. The system failed after 12 h, resulting in repeat I&D. Two days later, another I&D included placement of Penrose drains, which were removed at the bedside 4 days later. At the age of 16 days, the distal femoral EOC was faintly visible radiographically. From the 16th to the 28th day, the neonatologist and anesthesiologist believed that the patient was too frail for a general anesthetic. At 28 days, new metaphyseal subperiosteal bone was forming, which indicated healing osteomyelitis. On the 29th day, arthrotomy confirmed a detached, posteriorly displaced, mobile epiphysis, which was reduced and stabilized temporarily with crossed Kirschner wires. Antibiotics were continued for 6 weeks, well after the complete blood count, erythrocyte sedimentation rate, and C-reactive protein level had returned to normal. She also had a septic right ankle with osteomyelitis of the talus treated with I&D. The patient was discharged home at 2 months of age with no further signs of infection. She began walking at the age of 13 months, at which time the left femur was 1.6 cm shorter than the right, the distal femoral metaphysis was irregularly shaped and irregularly ossified, and there was no ossification in the distal femoral epiphysis (Fig. 4a). At the age of 3 years and 4 months, the patient was walking with a shoe lift
(Fig. 4b). There was 45° of genu valgum. At the age of 3 years and 5 months, the apex of the central physeal arrest was excised by direct vision through a transverse osteotomy of the distal femoral metaphysis. The surgeon noted a thin line of normal white physeal cartilage circumferentially in the cavity. The cavity was lined with bone wax and filled with fat. After correcting the valgus deformity, the osteotomy was fixed with crossed Kirschner wires. No metal markers were inserted. At last follow-up, at the age of 7 years and 1 month, 3 years and 9 months after PBE excision, the distal femur was growing with continuing bifid ossification of the epiphysis (Fig. 4c). The left femur was 4.8 cm shorter than the right, but because of relative overgrowth of the left tibia, the left lower extremity was only 3.2 cm shorter than the right. Although the PBE excision was useful in re-establishing growth, this patient will require follow-up until maturity. Early premature, spontaneous, complete arrest of the distal left femoral physis can be expected, requiring major limb-equalization procedures, as in case 3 (case contributed by Dr Richard Munk, Toledo, Ohio, USA, with permission).
Discussion At birth, and for a variable time thereafter, most epiphyses have no ossification center. The distal femur is the only epiphysis that typically, but not always, has an ossification center at birth. Before the development of an EOC, injury to the physis can cause premature partial physeal death, without development of an osseous bar (a PBE). The same result can occur with an immature EOC surrounded by abundant hyaline cartilage, which makes it relatively difficult for a bone bar to develop from the metaphysis to the EOC. Features present in each case of PBE reported here include (a) septic arthritis of a knee joint and/or osteomyelitis of the distal femur in a child younger than 11 months; (b) an absent or immature distal femoral EOC; (c) death of a portion of the distal femoral physis in or near the center of the physis; (d) subsequent deformity of the metaphysis, physis, and epiphysis; (e) impaired longitudinal femoral growth with angular deformity; and (f) no radiographically identifiable osseous bar from metaphysis to epiphysis. Metaphyseal osteomyelitis and septic arthritis often coexist at the time of presentation (as they apparently did in these four cases), and it may be impossible to determine which came first. Septic arthritis may be a byproduct of a nidus of metaphyseal osteomyelitis that has infiltrated the joint and spread through the epiphyseal vessels into the epiphysis and then to the physis. Although S. aureus was cultured in all four cases, it seems likely that the same condition could result from infectious organisms other than S. aureus.
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Physeal bar equivalent Peterson et al. 513
Fig. 4
(a)
(b)
(c) 3+4
1+1
12.5 14.1
11.6 11.6
Case 4: (a) 1 year postoperatively, the left epiphyseal ossification center was absent radiographically; (b) at the age of 3 years and 4 months, the patient was walking with a left shoe lift; (c) at the age of 7 years and 1 month, the left femur was growing well. The physis was open and the epiphysis had reossified but was bifid.
Radiographic disappearance and subsequent reappearance of the EOC, as noted in cases 3 and 4, occurred months after the original acute infection and has been discussed previously with illustrations and references [3–5]. The fact that epiphyseal cartilage can reconstitute a new EOC suggests that reparative hyper-revascularization is responsible for the radiographic disappearance of the ossification center rather than enzymatic dissolution of bone by the infecting organism [4]. The reossified EOC may be small, bifid, or irregular [5], with consequent epiphyseal deformity. PBE excision provided some growth in each case. In case 1, the involved physis grew as well as its normal contralateral counterpart for 12 years after PBE excision, but closed before the other three uninjured major knee physes. Thus, contralateral surgical physeal arrests were used to prevent additional limb-length discrepancy and to improve it as the patient completed growth. This excellent result was because of early recognition and treatment of the PBE. PBE excision re-established growth in case 3, but the physis closed completely before maturity. PBE excision re-established growth in cases 2 and 4, and their outcome is still pending. These patients need careful follow-up because their involved physis is anticipated to also close early, near maturity or sooner.
In case 1 in this patient series, 20° angular deformity corrected spontaneously to normal by PBE alone. Case 2 had 30° of angular deformity, corrected partially by PBE excision, and was definitively treated with an eight-plate (tension band plate). Cases 3 and 4 had more than 30° angular deformity and were treated with corrective osteotomy. Additional reported sites of the same PBE phenomena include the distal humerus, where it is referred to as the fishtail deformity [6–9], long bone physes in some newborns with intrauterine vascular deficiency [10–15], and the proximal femoral physis of children born prematurely, with neonatal S. aureus hip infection [16]. Treatment
For the cases reported here, early diagnosis and treatment of both the initial infection and the resulting growth arrest were the keys to a successful outcome (Table 1). The management of acute infection near a physis, whether intraosseous or intra-articular, is a race against time. Delays in the diagnosis or institution of care are the most important factors affecting outcome [17–20]. The only emergency orthopedic surgery necessary in children, other than for trauma, is for acute osteomyelitis near a physis or acute septic arthritis. Patients who seek care late in the evening or in early morning hours should go to surgery immediately, without waiting for the morning. The interplay between bone or joint aspiration, aspiration
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514 Journal of Pediatric Orthopaedics B 2017, Vol 26 No 6
and lavage, repeated aspiration, continuous irrigation, I&D, packing the wound open, and the role and choice of antibiotics can all be debated, but every hour that an acute suppurative process continues untreated near a physis is of urgent significance and will negatively affect the ultimate outcome.
Conflicts of interest
There are no conflicts of interest.
References 1
Similarly, once a PBE deformity is identified, the sooner the area of the deficient physis is removed and replaced by an interposition material, the better the result (case 1). This requires close follow-up after the infection and close long-term follow-up after PBE excision as physeal closure can reoccur at any time and be partial or complete (case 3), most predictably near completion of growth. Indications for PBE excision surgery include a progressive bonelength discrepancy or angular deformity. Surgery should not be performed in the absence of such deformity. In this case series, the two patients (cases 1 and 2) who had the PBE removed and replaced by an interposition material within 2 and a half years of infection resumed normal growth and required only contralateral surgical physeal arrests to achieve acceptable leg-length equality (Table 1). In the other two cases (3 and 4), although surgical removal of the PBE resulted in the resumption of valuable growth, the loss of growth and angular deformity were too great to be fully corrected by bar excision alone, and reconstructive surgery was performed or will be needed.
2 3 4 5
6
7
8
9 10 11 12
Summary
This case series has defined and illustrated the PBE. All four cases were characterized by infection near the distal femoral physis in a child younger than 11 months of age. This resulted in the death of the involved portion of the physeal cells and produced metaphyseal, physeal, and epiphyseal deformities similar to those observed with a typical physeal bar, but without the bone bar from metaphysis to epiphysis. Two cases treated with early PBE excision required less reconstructive surgery.
13
14 15 16
17 18
Acknowledgements Portions of cases 1, 2, and 3 were previously published in Peterson [3]. Used with permission of Mayo Foundation for Medical Education and Research.
19 20
Peterson HA. Partial growth plate arrest and its treatment. J Pediatr Orthop 1984; 4:246–258. Peterson HA. Epiphyseal growth plate fractures. Heidelberg, Germany: Springer; 2007. Peterson HA. Physeal injury other than fracture. Heidelberg, Germany: Springer; 2012. Wood BP. The vanishing epiphyseal ossification center: a sequel to septic arthritis of childhood. Radiology 1980; 134:387–389. Jaimes C, Chauvin NA, Delgado J, Jaramillo D. MR imaging of normal epiphyseal development and common epiphyseal disorders. Radiographics 2014; 34:449–471. Yang Z, Wang Y, Gilula LA, Yamaguchi K. Microcirculation of the distal humeral epiphyseal cartilage: implications for post-traumatic growth deformities. J Hand Surg Am 1998; 23:165–172. Nwakama AC, Peterson HA, Shaughnessy WJ. Fishtail deformity following fracture of the distal humerus in children: historical review, case presentations, discussion of etiology, and thoughts on treatment. J Pediatr Orthop B 2000; 9:309–318. Schulte DW, Ramseier LE. Fishtail deformity as a result of a non-displaced supracondylar fracture of the humerus. Acta Orthop Belg 2009; 75:408–410. Glotzbecker MP, Bae DS, Links AC, Waters PM. Fishtail deformity of the distal humerus: a report of 15 cases. J Pediatr Orthop 2013; 33:592–597. Armstrong AP, Page RE. Intrauterine vascular deficiency of the upper limb. J Hand Surg Br 1997; 22:607–611. Carr MM, al-Qattan M, Clarke HM. Extremity gangrene in utero. J Hand Surg Br 1996; 21:652–655. Gosain AK, Moore FO, Rabinowitz LG. Congenital pressure necrosis of the forearm in a newborn infant. Ann Plast Surg 2000; 45:318–322. (discussion 322–328). Ragland R, Moukoko D, Ezaki M, Carter PR, Mills J. Forearm compartment syndrome in the newborn: report of 24 cases. J Hand Surg Am 2005; 30:997–1003. Silfen R, Amir A, Sirota L, Hauben DJ. Congenital Volkmann–Lesser ischemic contracture of the upper limb. Ann Plast Surg 2000; 45:313–317. Tsujino A, Hooper G. Neonatal compression ischaemia of the forearm. J Hand Surg Br 1997; 22:612–614. Song HR, Oh CW, Guille JT, Song KS, Kyung HS, Kim SY, Park BC. Lateral growth disturbance of the proximal femur in premature infants who had neonatal sepsis. J Pediatr Orthop B 2006; 15:178–182. Paterson DC. Acute suppurative arthritis in infancy and childhood. J Bone Joint Surg Br 1970; 52:474–482. Gillespie R. Septic arthritis of childhood. Clin Orthop Relat Res 1973; 96:152–159. Morrey BF, Bianco AJ Jr, Rhodes KH. Septic arthritis in children. Orthop Clin North Am 1975; 6:923–934. Nade S, Nade S, Nade S. Acute septic arthritis in infancy and childhood. J Bone Joint Surg Br 1983; 65:234–241.
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