Percutaneous vs modified phemister epiphysiodesis of the lower extremity

Are percutaneous epiphysiodesis and Phemister technique effective in the treatment of leg-length discrepancy? A systematic review

Epiphysiodesis is considered the preferred treatment for children predicted to have leg length discrepancies (LLDs) 2-5 cm at maturity. The aim of this study was to systematically review the existing literature on the effectiveness of permanent epiphysiodesis for LLD treatment, and secondarily to address the reported complications of permanent epiphysiodesis techniques. This systematic review was performed according to PRISMA guidelines. We searched MEDLINE (PubMed), Embase, Cochrane Library, Web of Science and Scopus for studies on skeletally immature patients with LLD treated with permanent epiphysiodesis. The extracted outcome categories were effectiveness of epiphysiodesis (LLD measurements pre/post-operatively, successful/unsuccessful), physeal fusion/arrest, and complications that were graded on severity. Forty-nine studies (3051 patients) were included, 1550 underwent Phemister/modified Phemister epiphysiodesis and 1501 percutaneous epiphysiodesis (PE). Total successful permanent epiphysiodesis surgeries (16 studies) were 73.7% (516/700). Only 13 out of 23 studies had a mean final LLD of less than 1.5 cm. In total, 17.5% (513/2936) of complications were reported. 57 angular deformities were reported (1.9%). Phemister technique had higher percentage of complications (39%) than PE (19.1%) in total, but when failure to achieve adequate reduction in LLD was not included, complication rates for both were close to 14%. However, severe complications were 10.2% for Phemister group and 5.1% for PE. The high complication rates and the relative low success rate call for optimization of the timing and the applied techniques when treating LLD with permanent epiphysiodesis. Phemister technique was found to have higher percentage of severe complications than PE. Registration: PROSPERO (CRD42023435177).

Angular deformities after percutaneous epiphysiodesis for leg length discrepancy

PURPOSE

The purpose of this study was to systematically analyze the presence of secondary angular deformities after percutaneous epiphysiodesis based on long-standing radiographs, and to see if the occurrence and magnitude of angular deformities after percutaneous epiphysiodesis correlated with the amount of remaining growth at the time of surgery.

METHODS

From a local Health Register consisting of patients investigated using the Moseley Straight-Line Graph, we identified 269 patients who had undergone percutaneous epiphysiodesis from 2002 until 2020. Radiographic analysis included the measurement of mechanical axis and joint orientation angles on long-standing anterior-posterior radiographs. Remaining growth was analyzed based on the Menelaus method.

RESULTS

One hundred and forty epiphysiodeses (71 femurs and 69 tibiae) in 88 patients (39 girls and 49 boys) could be included in the study. Mean age at surgery was 13.2 (10-16.8) years, and mean skeletal age at surgery was 13.0 (9.8-15.7) years. A change of the MA (Mechanical axis) ≥10 mm was found in eight patients (9%). Secondary frontal plane deformities after percutaneous epiphysiodesis correlated significantly with the remaining growth at the time of surgery (p = 0.003).

CONCLUSION

We found a high rate of secondary angular deformities after percutaneous epiphysiodesis, and the magnitude of the deformities correlated with the amount of remaining growth at the time of surgery. A modification of the original surgical method for percutaneous epiphysiodesis to also include ablation of central parts of the growth plate might be considered. Patients should be enrolled in a systematic follow-up scheme which allows for the early detection of possible angular deformities.

LEVEL OF EVIDENCE

level III study.

Postoperative growth rate affects time to growth arrest after percutaneous physiodesis: A radiostereometric analysis

PURPOSE

The aim of this study was to determine the time at which physeal arrest is achieved after percutaneous physiodesis, and whether immediate postoperative growth rate affects the time to reach physeal arrest.

METHODS

Radiostereometric analysis, with implantation of tantalum balls as radiographic markers on each side of the physes, was used to measure residual longitudinal growth in 21 children (10 boys and 11 girls) after percutaneous physiodesis for leg length discrepancy or extreme tall stature. In total, 25 femoral and 20 tibial physes were operated on. Median age at surgery was 13.9 years (range = 11.4-16.1). Radiostereometric analysis was performed postoperatively and after 3, 6, 9, 12, 26, and 52 weeks. Longitudinal growth rate <50 µm per week was defined as physeal arrest. Descriptive statistics were used for evaluation.

RESULTS

Physeal arrest was obtained in 19 of the 21 children (40 physes) within 12 weeks postoperatively. One child was reoperated on in three out of four physes because of continued growth, and in one child, delayed physeal arrest was present at 26 weeks postoperatively. Time to physeal arrest was longer in physes with a higher immediate postoperative growth rate.

CONCLUSION

Postoperative follow-up with radiostereometric analysis at 12 and 15 weeks can determine whether physeal arrest has been achieved. The immediate postoperative growth rate after physiodesis seems to affect the time to physeal arrest. This implies that the risk for complications is greater for children during an accelerated growth period, for example, in boys, younger children and in distal femoral physes.

LEVEL OF EVIDENCE

level III.

Gradual Deformity Correction with a Computer-assisted Hexapod External Fixator in Blount\'s Disease

Aim

To evaluate the results in terms of correction and complications from gradual correction with a computer-assisted hexapod circular external fixator in a mixed cohort of children with Blount's disease.

Materials and methods

A retrospective review was performed of the correction and complications of 19 children (25 limbs) with recurrent infantile (IBD) and late-onset Blount's disease (LOBD) treated by gradual correction with a hexapod external fixator. The correction was measured by the medial proximal tibial angle (MPTA), anatomic posterior proximal tibial angle (aPPTA) and anatomic tibio-femoral angle (TFA). Obesity was present in 76% (19/25) of cases. Fifteen limbs were classified as infantile Blount's disease and 10 limbs as late-onset Blount's disease. The mean age was 12.5 years (range 7–17 years).

Results

The mean pre-operative MPTA of 59° (SD 13°, range 33–79°) was corrected to a mean of 86° (SD 5°, range 77–93°). The mean pre-operative aPPTA of 64° (SD 14°, range 33–84°) was corrected to 79° (SD 6°, range 70–90°). The median pre-operative rotation of 15° internal rotation was corrected to normal (0–15° of external rotation). Eight out of 25 limbs had severe deformities with varus or procurvatum greater than 40° or both. The mean pre-operative TFA of 28° varus (SD 13°, range 4–53°) was corrected to 1.8° valgus (SD 6°, range 14° varus to 13° valgus). The median follow-up was 19 months (range 6–67 months). The alignment after correction was “good” in 55% (11/20), “acceptable” in 35% (7/20) and “poor” in 10% (2/20).

The median duration for correction was 16 days (IQR 11–31 days, range 7–71 days). The median number of prescribed correction programmes was 1 (IQR 1–2, range 1–5). The mean total time in the frame was 136 days (SD 34 days, range 85–201 days).

All patients developed minor pin track infections that resolved with oral antibiotics (Category 1 complications). Four patients developed complications that necessitated modification of the treatment plan (Category 2 complications). In two cases, treatment objectives could not be achieved (Category 3 complications). Two patients treated before skeletal maturity developed recurrent genu varum.

Conclusion

Gradual correction with a computer-assisted hexapod external fixator may be a useful technique for correcting recurrent IBD or LOBD even in children with severe deformities. The results of gradual correction were similar in the two groups. While complications occur, most can be mitigated by timely intervention during the correction phase of treatment. Recurrence remains a concern if correction is performed before skeletal maturity.

Level of evidence

4.

How to cite this article

Mare PH, Marais LC. Gradual Deformity Correction with a Computer-assisted Hexapod External Fixator in Blount's Disease. Strategies Trauma Limb Reconstr 2022;17(1):32–37.

[Epiphysiodesis and hemiepiphysiodesis : Physeal arrest and guided growth for the lower extremity]

The principals of growth arrest by epiphysiodesis and growth guidance by hemiepiphysiodesis are effective and powerful surgical techniques in pediatric orthopedics. These procedures can be used to correct leg length discrepancies as well as sagittal, coronal and oblique deformities. A differentiation is made between temporary and permanent techniques. The most significant advantage is that these techniques are minimally invasive and have low complication rates compared to acute osteotomy and gradual deformity correction. For optimal outcome an exact preoperative planning is needed to ensure accurate timing of the procedure, especially when permanent epiphysiodesis techniques are used. Although epiphysiodesis and hemiepiphysiodesis around the pediatric knee are most frequently used and can be considered the gold standard treatment of coronal plane deformities and leg length discrepancies, novel techniques for the hip and ankle are increasingly being performed. The successful clinical results with low complications support the broad use of hemiepiphysiodesis and epiphysiodesis for a variety of indications in the growing skeleton with deformities and leg length differences.

The single portal percutaneous epiphysiodesis technique for treatment of leg length inequality stops growth as expected

One technique for distal femur and proximal tibia epiphysiodesis to treat leg length inequality is a single-incision percutaneous technique using reamers and curettes. The purpose of this study is to demonstrate the efficacy and reliability of this technique by quantifying the growth arrest produced from this method. Patients who underwent distal femur and proximal tibia epiphysiodesis with a single-incision percutaneous technique were retrospectively reviewed. Using scanogram data, derivative formulas of both the multiplier and arithmetic methods were used to predict bone length after physeal arrest at maturity. Patients included had at least 2-year follow-up after surgery. Predicted bone lengths were then compared to actual bone lengths obtained via scanogram at final follow-up. A total of 46 patients were included in the study (27 males; 19 females). Average age at surgery was: males 14.5 years, females 12.4 years. Surgery was performed on 40 distal femurs and 25 proximal tibias. Postoperative femurs demonstrated an actual mean length of 44.75 cm. Predicted femur bone lengths utilizing the multiplier and arithmetic methods were 45.08 and 44.08 cm, respectively. Postoperative tibias demonstrated an actual mean length of 38.12 cm. Predicted tibia lengths utilizing the multiplier and arithmetic method were 38.30 and 38.02 cm. No significance was found between actual and predicted bone lengths for both tibias and femurs. This study demonstrates that a single-incision percutaneous epiphysiodesis technique reliably arrests the growth as expected. Surgeons can confidently and accurately employ this technique to successfully treat leg length inequality.

The Medial Elevation Osteotomy for Late-presenting and Recurrent Infantile Blount Disease

BACKGROUND

Late-presenting or recurrent infantile Blount disease (IBD) is characterized by knee instability because of medial tibial plateau depression, multiplanar proximal tibial deformity, and potential distal femoral deformity. The surgical treatment strategy includes medial elevation osteotomy to stabilize the knee, together with proximal tibial osteotomy to correct alignment, and lateral epiphysiodesis to prevent a recurrence. This study's primary aim was to describe the clinical outcomes of medial elevation osteotomy for the management of late-presenting and recurrent IBD.

METHODS

The authors reviewed the records of 48 children (64 limbs) who had medial elevation osteotomies and lateral epiphysiodesis, combined with proximal tibial realignment in 78% (50/64) of cases in the same setting. IBD was bilateral in 33% (16/48), 77% (37/48) were female individuals, and 42% (20/48) were obese.

RESULTS

The mean age at surgery was 8.6 years (SD, 1.6; range, 5.8 to 12.8). The mean preoperative tibiofemoral angle (TFA) was 28±11 degrees (8 to 55 degrees), and the mean angle of depression of the medial plateau (ADMP) was 49±8 degrees (26 to 65 degrees). Distal femoral valgus was present in 27% (17/62) and varus in 10% (6/62) children. At a median follow-up of 3.2 years (range, 1 to 6.2 y), the median TFA was 1-degree valgus (interquartile range, 7-degree varus to 5-degree valgus), whereas the ADMP was corrected to 25±8 degrees (8 to 45 degrees). Obesity was associated with more severe deformity as measured by TFA (P<0.001) but did not affect the extent of medial plateau depression (P=0.113). The good or excellent alignment was achieved in 75% (47/63) limbs. Obesity was associated with an increased risk of recurrence [odds ratio (OR), 5.21; 95% CI, 1.26-21.63; P=0.023]. Age at the surgery or previous surgery was not associated with recurrence (OR, 1.29; 95% CI, 0.88-1.88; P=0.195 and OR, 1.22; 95% CI, 0.36-4.17; P=0.746). Obesity and residual instability were associated with an increased risk of poor alignment at the latest follow-up (OR, 3.24; 95% CI, 1.02-10.31; P=0.047 and OR, 1.21; 95% CI, 1.05-1.40; P=0.008).

CONCLUSION

Late-presenting or recurrent IBD is a surgical challenge. Obesity is associated with more severe deformity. Medial elevation osteotomy combined with lateral proximal tibial epiphysiodesis and metaphyseal tibial realignment osteotomy will result in restoration of lower limb alignment in a high proportion of cases. The recurrent deformity may be the result of failed epiphysiodesis. Obesity and residual instability are associated with an increased risk of poor alignment. Although complications are rare, surgical measures to decrease risk should be followed.

LEVEL OF EVIDENCE

Level IV.

Complications Associated With Epiphysiodesis for Management of Leg Length Discrepancy

BACKGROUND

Epiphysiodesis is well-established surgical treatment for the management of leg length discrepancy (LLD) in children; however, a variety of complications may occur. This study evaluates the nature, rate, and potential risk factors of complications associated with epiphysiodesis in a large patient population treated in 1 institution.

METHODS

We evaluated the medical and radiographic records of 863 children who had lower extremity epiphysiodesis to manage LLD between 1980 and 2011.

RESULTS

Sixty patients (7.0%) incurred complications of some type. Twenty-three patients (2.7%) had perioperative complications unrelated to physeal growth; all resolved without surgical treatment. These included 2 patients with transient intraoperative complications (laryngospasm and allergic rash), 7 with transient neurological symptoms (5 cutaneous nerve dysesthesia or numbness and 2 peroneal nerve neuropathies), and 14 with postoperative knee stiffness which resolved with therapy. Thirty-seven patients (4.3%) developed physeal growth-related complications, including 6 patients who developed overcorrection of leg length inequality (3 had contralateral epiphysiodesis to prevent overcorrection, while 3 declined), and 31 patients who developed angular deformity and/or continued growth of the physis. Of these 31 patients, 15 had reexploration of the epiphysiodesis site, 6 underwent corrective osteotomy, while in 10, no treatment was undertaken. Compared with patients who did not develop angular deformity, these 31 patients had significantly greater LLD (5.6 vs. 3.7 cm, respectively, P<0.01), were younger (10.7 vs. 11.7 in girls; 12.4 vs. 13.5 in boys; P<0.01), and were more likely to have a congenital etiology for their LLD (P<0.01).

CONCLUSIONS

Epiphysiodesis is a safe and effective procedure for the correction of leg length inequality. The rate of complications in this study was 7.0%, the most prevalent being the development of angular deformity. Congenital etiology, younger age, and larger limb length inequalities were risk factors for the development of angular deformity. Both surgeons and families should be aware of nature and rate of complications associated with epiphysiodesis.

LEVEL OF EVIDENCE

Level IV.

Endoscopic-assisted epiphysiodesis: technique and 20-year experience

The aim of the study was to describe the endoscopic-assisted epiphysiodesis technique and review our 20-year experience with it. A retrospective review of 44 patients who underwent proximal tibia and/or distal femur endoscopic-assisted epiphysiodesis was carried out. Only patients who had preoperative and postoperative scanograms with clinical follow-up of at least 6 months were included. The mean length of follow-up was 36.8 months. All patients had radiographic evidence of physeal fusion within 6-12 months from the index procedure. No patient required revision surgery. Endoscopic-assisted epiphysiodesis is safe, effective, and achieves predictable physeal fusion. Advantages over current techniques include reduced radiation exposure and lack of requirement for hardware placement.

Percutaneous epiphysiodesis in the proximal tibia by a single-portal approach: evaluation by radiostereometric analysis

PURPOSE

We modified the method for tibial epiphysiodesis by solely using a lateral approach to the physis. From this small-incision approach, the lateral as well as the medial part of the tibial physis were ablated. The aim of our study was to see if this operative technique might be as effective as a bilateral approach, and reduce the operation time and usage time of the image intensifier. The epiphysiodeses were monitored by radiostereometric analysis (RSA), which is a well-established method for the analysis of micro movements and has been used to monitor percutaneous epiphysiodesis with the bilateral approach. There are no reports in the literature comparing single- with double-portal approaches for percutaneous epiphysiodesis evaluated by RSA.

METHODS

Twenty children were treated by percutaneous epiphysiodesis for leg length discrepancies ranging from 15 to 70 mm, comprising 14 boys and 6 girls with a mean age of 13 (11-15) years. The timing of epiphysiodesis was determined by using Moseley's straight-line graph and Paley's multiplier method. For the tibial epiphysiodesis, ten patients were operated with a single surgical approach from the lateral side (Group I) and ten patients were operated with a surgical approach from both the medial and the lateral sides (Group II). The percutaneous epiphysiodesis was monitored by RSA, a method which allows analysis of the three-dimensional dynamics of the epiphysis relative to the metaphysics. RSA examinations were performed postoperatively and after 6 weeks, 12 weeks, and 6 months.

RESULTS

From 0 to 6 weeks after epiphysiodesis, the mean longitudinal growth across the operated physis in the tibia in Group I was 0.26 (0.01-0.6) mm. In Group II, the mean growth for the first 6 weeks after surgery was 0.17 (0.01-0.5) mm. During the time period from 6 weeks to 12 weeks after surgery, there was a mean growth of 0.06 (0.00-0.18) mm in Group I and 0.03 (0.00-0.2) mm in Group II. The mean growth from 0 to 6 weeks after epiphysiodesis for all patients was 0.22 mm, which corresponds to 30 % of the normal growth rate. From 6 to 12 weeks, the mean growth for all patients was 0.046 mm, i.e., 6 % of the normal growth rate. From 12 weeks to 24 weeks, no significant growth across the operated physis was observed in neither Group I nor Group II. The mean surgical time was 26 (21-30) min in Group I and 43 (35-48) min in Group II. This difference was statistically significant (p = 0.006). The mean time for use of the image intensifier during surgery was 202 (191-236) s in Group I and 229 (185-289) s in Group II (p = 0.013).

CONCLUSIONS

In our study, a single-portal technique from the lateral side for percutaneous epiphysiodesis of the proximal tibia was as effective as the double-portal technique. Actual growth arrest appeared within 12 weeks after surgery. A single-portal technique for epiphysiodesis of the tibia is a safe technique, with less surgical time and less time for image intensification compared to the double-portal technique.

Eight plate should not be used for treating leg length discrepancy

PURPOSE

The Blount staple has been widely used for treating angular deformities and leg length discrepancy (LLD) of the lower limbs. In recent years, the Eight plate has replaced the Blount staple for treating angular deformities in many centres. Although not described in the literature, it has been proposed that the Eight plate could also be used for treating LLD. We studied the effectiveness of the device for this indication.

METHODS

Ten patients with LLD were included prospectively. Medial and lateral plates were inserted for symmetrical growth reduction and the patients were followed by radiostereometric analysis (RSA) 0, 3, 6, 9, 12, 24, 52 and 80 weeks postoperatively. The error of measurement with this technique is less than 0.05 mm.

RESULTS

Case 1 continued to grow an average of 0.08 mm per week (6.7 mm longitudinal growth in 1.5 years) postoperatively, while Case 2 showed 0.07 mm longitudinal growth per week (5.6 mm longitudinal growth in 1.5 years). The longitudinal growth, in both children, showed only slight growth retardation throughout the follow-up period. The study was interrupted and no further subjects were included after the results indicated that only minor growth reduction had occurred in both patients.

CONCLUSION

The Eight plate does not significantly reduce growth when applied both medially and laterally in a symmetrical way at the proximal tibial physis.

Negative correlation between extent of physeal ablation after percutaneous permanent physiodesis and postoperative growth: volume computer tomography and radiostereometric analysis of 37 physes in 27 patients

BACKGROUND AND PURPOSE

Percutaneous physiodesis in the knee region is a well-established method for treating leg-length inequality. Longitudinal growth in the physis is believed to stop almost immediately after the operation. The extent of physis ablation required has never been investigated by any kind of tomography in humans. Using radiostereometric analysis (RSA), we determined when definite growth arrest occurred after surgery. We also studied the correlation between the extent of physis ablation and postoperative growth. Finally, we assessed any bone bridging across the physis.

METHODS

6, 12, and 30 weeks after surgery, we used RSA to measure longitudinal growth in 27 patients (37 physes) with a mean age of 13 years. CT scanning of the knee region was performed 12 weeks after surgery to measure the percentage of the ablated physis and to determine the distribution of bone bridges across the physis.

RESULTS

RSA showed that growth rate was reduced to less than half of the expected rate after 6 weeks. During the next 6 weeks, the growth ceased completely. CT scans revealed a large variation in the extent of ablated physes (17-69%). In the ablated areas, tissues of various densities were mixed with mature bone. Bridges were found both laterally and medially across the physes in all of the patients. There was a negative correlation between the extent of ablation and total postoperative growth (rho = -0.37, p = 0.03).

INTERPRETATION

Growth across the physis is effectively stopped by percutaneous physiodesis. RSA is well-suited for observation of this phenomenon. Volume CT scanning can be used to detect bone bridges that cross the physis and to calculate the extent of physis ablation.

Surgical epiphysiodesis indications and techniques: update

PURPOSE OF REVIEW

To present a summary of epiphysiodesis indications and to report most recent advances in the field, along with their clinical relevance.

RECENT FINDINGS

Percutaneous epiphysiodesis using transphyseal screws (PETS) and guided growth using eight plates represent the most recent techniques used for hemiepiphysiodesis.

SUMMARY

PETS and guided growth have yielded very good results and low rates of complications and are the current standard for the management of angular deformities of the lower extremities in children. Permanent percutaneous epiphysiodesis remains the preferred method for the treatment of limb length discrepancies.

Guided growth for the correction of pediatric lower limb angular deformity

Guided growth is useful in correcting pediatric angular deformities. Although growth manipulation has been applied to various deformities, it is most commonly used to correct coronal plane deformity about the knee. Temporary hemiepiphysiodesis is performed using staples, percutaneous transphyseal screws, or a tension band plate. Permanent hemiepiphysiodesis can be done using either an open Phemister or a percutaneous approach. These techniques function by tethering one side of a growing physis, thereby allowing differential growth. Applied correctly, this can also result in angular deformity correction. Undercorrection and overcorrection are common problems with guided growth. However, careful preoperative planning and appropriate follow-up can minimize complications and allow for excellent deformity correction with minimal morbidity.

Minimal invasive epiphysiodesis using a modified "Canale"-technique for correction of angular deformities and limb leg length discrepancies

PURPOSE

Leg length discrepancy and angular deformities can, in contrast to adults; easily be corrected with epiphysiodesis during growth. Goal of this study was to evaluate our results of a modified Canale technique for definitive epiphysiodesis treating leg length discrepancy and also angular deformities.

METHODS

Between 2000 and 2007, 22 patients (11 boys and 11 girls) were subjected to definitive epiphysiodesis. In total 73 hemiepiphysiodesis were performed (26 proximal tibial, 47 distal femoral).

RESULTS

All patients could be followed to the end of growth. Mean follow-up was 32.2 month (range 13-76 months). In 20 patients the epiphysiodesis was planed to correct axis and leg length discrepancy. In two patients' contralateral epiphysiodesis was performed to avoid further leg length discrepancy because of closed physis of the shorter affected side. A staged procedure was necessary in nine patients to achieve the best possible correction. No complications were seen such as wound healing, knee-joint contractures after epiphysiodesis of the distal femur and proximal tibia. In two patients three rehemiepiphysiodesis because of not fully closure of the physis had to be done.

CONCLUSION

Definitive epiphysiodesis using this modified Canale technique is a safe, minimal invasive method to correct leg length discrepancy and angular deformities if preoperative planning is performed properly.

Efficacy and safety of percutaneous epiphysiodesis

BACKGROUND

The aims of this study were to evaluate outcomes of percutaneous epiphysiodesis, as described by Bowen, in 97 patients and to assess complications and determine whether the effect of the epiphysiodesis will accurately follow the Moseley chart predictions.

METHODS

A total of 97 patients were reviewed retrospectively. Fifty-six girls and 41 boys, with a mean skeletal age of 12.6 years (range, 10-16 years) at the time of operation, were followed up until skeletal maturity, a mean of 3.8 years (range, 1-10 years).

RESULTS

The mean residual leg length discrepancy (LLD) in 88 patients at maturity was 1.3 cm (range, 0-3.5 cm). In 9 patients, the epiphysiodesis was combined with a femoral lengthening or femoral shortening. The residual leg length discrepancy in these 9 patients was 3.3 cm at maturity (range, 0-6.5 cm). Minor complications including knee effusion (n = 2), superficial wound infection (n = 1), and exostosis (n = 3) occurred in 6 patients. Failure of the epiphysiodesis was the only major complication seen (n = 3).

CONCLUSIONS

This study shows that complications are infrequent when performing percutaneous epiphysiodesis and that the Moseley straight-line method accurately and efficaciously predicted the timing for percutaneous epiphysiodesis in all but one patient who had unpredictable growth from hemihypertrophy secondary to a hemangiomatosis.

Hemiepiphysiodesis for the correction of angular deformity about the knee

BACKGROUND

It is generally accepted that the presence of angular deformity about the knee that persists into the preadolescent years will not correct spontaneously. The goal of this study was to review our experience with hemiepiphysiodesis and physeal stapling for the correction of angular deformity to establish the efficacy of these procedures and to determine their indications and the rate of correction.

METHODS

A retrospective review of 48 patients undergoing hemiepiphysiodesis or physeal stapling about the knee was performed. Patients were included if they had at least 2 years of documented follow-up without an osteotomy.

RESULTS

The average follow-up was 30.4 months (range, 24-52 months). Genu varum was identified in 33 patients, genu valgum in 14 patients, and a windswept deformity in 1. Of the 52 limbs with genu varum, 35 were secondary to Blount disease. The group with genu varum unrelated to Blount disease presented a change in the mechanical axis from a mean of -32 degrees at surgery to a mean of - 13 degrees. The patients with Blount disease presented a change in the mechanical axis from a mean of -19 degrees at surgery to a mean of -16 degrees. The group with genu valgum presented a change in the mechanical axis from a mean of 20 degrees at surgery to a mean of 2 degrees.

CONCLUSIONS

Hemiepiphysiodesis is an effective means for correcting angular deformity about the knee in skeletally immature patients with both genu valgum and genu varum, so long as the genu varum is unrelated to Blount disease. Hemiepiphysiodesis is effective in preventing the progression of deformity in patients with Blount disease.

LEVEL OF EVIDENCE

Therapeutic-Level IV.

The correction of leg-length discrepancy after treatment in developmental dysplasia of the hip by using a percutaneous epiphysiodesis

The aims of this study were to determine factors that cause a leg-length discrepancy (LLD) to the extent that correction is indicated after treatment in developmental dysplasia of the hip and determine whether the LLD may be treated with a percutaneous epiphysiodesis. Twelve children were included in this study. The factors which caused LLD were avascular necrosis, femoral shortening and varus at reduction, and septic arthritis. Percutaneous epiphysiodesis of the contralateral limb reduced the mean predicted LLD from 3.8 to 1.2 cm at maturity. We concluded that LLD (>2.5 cm) might result from complications of developmental dysplasia of the hip and these patients can be treated with a percutaneous epiphysiodesis.

Epiphysiodesis with infusion of stromal cell-derived factor-1 in rabbit growth plates

BACKGROUND

The mechanism of physeal closure is poorly understood, although both mechanical and biological factors may play a role in the process. In this study, we evaluated the effect of the application of a chemokine stromal cell-derived factor-1 (SDF-1) to rabbit physes in vivo with regard to growth inhibition.

METHODS

A continuous infusion system consisting of a fenestrated catheter and an osmotic pump were implanted into the right proximal tibial physis of twenty six-week-old New Zealand White rabbits. Ten of the pumps were loaded with human recombinant SDF-1alpha, and ten were loaded with phosphate-buffered saline solution (sham treatment). The left leg was used as the uninvolved control. The growth of the tibiae was followed radiographically for eight weeks, and histologic analysis was performed for both the SDF-1-treated rabbits and the sham-treated rabbits at two, four, and eight-week time-points.

RESULTS

Radiographic evaluation showed a significant growth inhibition in the SDF-1alpha-treated physes (4.5 +/- 3.0 mm; p = 0.007) compared with the sham-treated physes after eight weeks. No difference was noted when the sham-treated leg was compared with the contralateral, control leg (0.2 +/- 2.9 mm; p = 0.465). Histologic evaluation showed marked physeal disorganization, narrowing, and proteoglycan loss and a significant decrease in physeal height (p < 0.0001) for the SDF-1-treated group. Reversible growth slowing was noted in the uninvolved, control leg of the SDF-1-treated group at six weeks, with resolution of the difference by eight weeks.

CONCLUSIONS

SDF-1 may be used to induce physeal closure through a targeted infusion system. However, transient systemic effects of SDF-1 may exist and must be evaluated further prior to its clinical use for epiphysiodesis.

Radiostereometric analysis for monitoring percutaneous physiodesis. A preliminary study

Percutaneous physiodesis is an established technique for treating mild leg-length discrepancy and problems of expected extreme height. Angular deformities resulting from incomplete physeal arrest have been reported, and little is known about the time interval from percutaneous physiodesis to actual physeal arrest. This procedure was carried out in ten children, six with leg-length discrepancy and four with expected extreme height. Radiostereometric analysis was used to determine the three-dimensional dynamics of growth retardation. Errors of measurement of translation were less than 0.05 mm and of rotation less than 0.06 degrees. Physeal arrest was obtained in all but one child within 12 weeks after physiodesis and no clinically-relevant angular deformities occurred. This is a suitable method for following up patients after percutaneous physiodesis. Incomplete physeal arrest can be detected at an early stage and the procedure repeated before corrective osteotomy is required.