Hemiepiphysiodesis around the knee by percutaneously guided and grooved staple

Surgical approach to correction of severe knee malalignment in a pediatric population in Tanzania

AIM

Severe knee malalignment in children usually needs surgery with different options available in surgical approaches. The aim of this study was to report the results of the surgical correction of severe knee malalignment in children treated with femoral and tibial osteotomy, temporarily fixed with percutaneous Kirschner wires, in a low- and middle-income country (LMIC), with limited medical resources.

Does the Sleeper Plate Application for Temporary Epiphysiodesis Make Life Easier or Complicated? Increased Risk of Tethering

BACKGROUND

The present study aims to investigate the frequency of recurrence and tethering effect after only metaphyseal screw removal (sleeper plate technique) compared with the conventional complete plate removal in the treatment of lower extremity deformities with guided growth surgery.

METHODS

Seventy-two patients (107 limbs) treated by an 8-plate hemiepiphysiodesis technique around the knee joint were evaluated. After the desired correction, only metaphyseal screw was removed (sleeper plate group) in 35 limbs (25 patients), whereas both screws and plate were removed (plate removal group) in 72 limbs (47 patients). An increase of 5 degrees or more in joint orientation angles in the direction of the initial deformity was considered as recurrence. The rate of rebound, tethering, and maintenance of correction in groups was analyzed at the latest follow-up (mean of 49 mo).

RESULTS

The mean age of the patients was 97 months (range: 80 to 129 mo) at the time of index surgery. After a mean of 49 months (range: 16 to 86), 17 (48.5%) limbs maintained the desired stable correction in the sleeper plate group compared with 59 stable limbs (72.2%) in the plate removal group ( P <0.001). There was no statistically significant difference regarding recurrence between the sleeper plate group and the plate removal group (34.3% vs. 27.8%, respectively) ( P =0.216). Reinsertion of the metaphyseal screw was possible 8/12 limbs, and the remaining 4 limbs underwent further surgeries. There were 6 limbs (17.3%) of tethering in the sleeper plate group, and 4/6 limbs required further corrective surgeries. The remaining 2 limbs with slight tethering did not require further surgeries.

CONCLUSIONS

Removing only metaphyseal screw increases the risk of tethering. In addition, reinsertion of the screw may not be possible in all cases due to bony growth, and further corrective surgeries may be necessary. Close follow-up is required if the sleeper plate technique is to be applied.

LEVEL OF EVIDENCE

Level III.

Hemiepiphysiodesis for Idiopathic Genu Valgum Using Physeal Staples Versus Tension-Band Plating: A Systematic Review

This review assesses the outcomes of hemiepiphysiodesis in patients with idiopathic genu valgum (IGV) treated with physeal staples vs tension-band plating (TBP). A systematic review of the literature was conducted to identify articles examining the use of physeal staples vs TBP for the treatment of IGV in skeletally immature patients. No significant difference in overall mean deformity correction (P=.92) or correction per month (P=.61) was observed between groups. Repeat hemiepiphysiodesis was more common in patients who underwent TBP vs physeal staples (P=.05). Tension-band plating did not yield significantly improved results compared with physeal staples in skeletally immature patients with IGV. [Orthopedics. 2019; 42(6):e485-e491.].

Growth modulation in idiopathic angular knee deformities: is it predictable?

PURPOSE

To evaluate the temporal and spatial sequence of events following temporal hemiepiphysiodesis in idiopathic knee varus/valgus.

METHODS

This is a retrospective multicentre study on 372 physes in 206 patients. The average rate of correction (ROC) was calculated; univariate and multivariate analysis were performed.

RESULTS

In all, 92% of the femoral physes were followed for more than one year/reached skeletal maturity. Of those, 93% were corrected to a mechanical lateral distal femoral angle (mLDFA) of 85° to 89°; 2% did not, while 5% were over-corrected. A total of 92% of the tibial physes were followed for more than one year/reached skeletal maturity. Of those, 92% were corrected to a mechanical medial proximal tibial angle (mMPTA) of 85° to 89°; 2% did not, while 6% were over-corrected. Factors significantly influencing success and ROC were age, direction and magnitude of deformity. Femoral ROC was significantly faster than tibial ROC: 0.85° versus 0.78°/month, respectively (p = 0.05). Femoral valgus ROC was significantly faster than varus ROC: 0.90° versus 0.77°/month, respectively (p = 0.04). A constant was derived to calculate the amount of correction. Significant correlation was found between calculated and actual mLDFA in valgus deformity during the first year (r = 0.58 to 0.87, p < 0.01). Calculated mLDFA of varus deformity did not correlate with actual mLDFA. Significant correlation was found when calculating mMPTA correction in all deformities.

CONCLUSIONS

Femur corrects faster than tibia; valgus femoral deformities are corrected faster than varus. Valgus correction in the distal femur/proximal tibia as well as varus correction in the tibia in idiopathic patients is highly predictable. The constant derived is the first tool which enables predicting and monitoring amount of correction in hemiepiphysiodesis when correcting angular deformities around the knee.

LEVEL OF EVIDENCE

IV.

Removal of Metaphyseal Screw Only After Hemiepiphysiodesis Correction of Coronal Plane Deformities Around the Knee Joint: Is This a Safe and Advisable Strategy?

PURPOSE

Correcting lower limb angular deformities in the skeletally immature patient with guided growth is a very common procedure. Using an 8-plate construct to produce reversible hemiepiphysiodesis allows correction of the mechanical axis of the limb. It has become routine strategy to remove only the metaphyseal screw from the 8-plate construct after desired correction is achieved, in order to ease its reinsertion in case of deformity recurrence. In this study, we evaluated the efficacy and safety of this technique.

METHODS

We reviewed the results of 80 patients (133 limbs) who were treated by guided growth using 8-plate hemiephisiodesis around the knee. After achievement of the correction goal, both screws and plate were removed in 78 limbs while only the metaphyseal screw was removed in 55 limbs.

RESULTS

The mean age of patient was 8.9 years at the time of surgery. Within the group whose metaphyseal screw was removed, 12 limbs showed radiographic signs of deformity recurrence and underwent reinsertion of the metaphyseal screw. In 9 of the cases of metaphyseal screw reinsertion, the plate or its location had to be changed (mean follow-up after screw removal was 14 mo). There were 2 cases where leaving the plate with an epiphyseal screw caused a radiographic bone bar and undesired clinical growth arrest.

CONCLUSIONS

On the basis of our experience, leaving the 8-plate construct with an epiphyseal screw in place exposes the patient to risks of bony bar, growth arrest, and an additional surgery for hardware removal. The majority of 8-plate constructs are not suitable for reinsertion of the metaphyseal screw.

Guided growth: preliminary results of a multinational study of 967 physes in 537 patients

BACKGROUND

Guided growth by tension band plating is commonly used to correct coronal plane deformity. The purpose of this study was to measure the effect and further define parameters that influence results in coronal plane deformity around the knee.

METHODS

The retrospective multicentre study included data on 967 physes in 537 patients, with an average follow-up of 16 months after plate insertion. Alignment analysis was compared preoperatively and in at least two measurements postoperatively, as well as with parameters that influence the rate and amount of correction.

RESULTS

Average age at plate implantation was 11.35 years (SD 3.29).Of those with femoral deformities, 85% of the patients finished the treatment and of those, 70% were corrected to standard alignment, while 14% have not yet achieved correction, and are still growing.Of those with tibial deformities, 75% of the patients finished the treatment and of those 80% were corrected to standard alignment, while 25% have not yet achieved correction and are still growing.The calculated rate of correction was 0.77°/month for the femur and 0.79°/month for the tibia.In terms of complications, the overall rate of infection was 1.48%. In three patients (0.55%) screw breakage was recorded.Factors found to significantly influence the amount of correction were age at plate implantation and direction of deformity.

CONCLUSION

Temporary hemiepiphysiodesis takes the advantage of physiological physeal growth to effectively treat angular deformities. Success of treatment is influenced by the age of the patient at plate implantation and direction of deformity.

LEVEL OF EVIDENCE

IV.

Treatment of genu valgum in children by means of temporary hemiepiphysiodesis using eight-plates: short-term findings

Background

Idiopathic genu valgum is a frequently diagnosed growth disorder in adolescence. Whenever the possibilities of conservative therapy have been exhausted, leg straightening by means of hemiepiphysiodesis has become the standard form of treatment. Because of their flexible screw-plate connection, eight-Plates have been reported in the literature to lead to lower complications regarding implant loosening and fracture compared to other implants.

The aim of this retrospective survey was to analyse our own patient population who were treated for genu valgum by means of temporary hemiepiphysiodesis near the knee using eight-Plates to modulate growth.

Methods

Between July 2007 and July 2015, 198 eight-Plates were implanted near the knee in 132 children suffering from genu valgum to modulate growth. Depending on the deformity analysis, an eight-Plate was implanted on the distal medial femur and/or the proximal medial tibia. By December 2015, they had been removed from 105 patients. The etiology of genu valgum was mainly idiopathic or associated withobesity. Evaluation was carried out clinically and radiologically (whole-leg X-ray in standing) including determination of the joint angles.

Results

The median follow-up period was about 46 months (12–102 months). The median age at implantation was 12.7 +/−6.76 years. Of the 105 patients, 45.7% (n = 48) were girls. The eight-Plates remained in place for a median period of 13 +/−1.76 months. Irrespective of the location of hemiepiphysiodesis, the intermalleolar distance was corrected to a median of 0 +/−2.1 cm while the anatomical femorotibial angle was corrected by on average 9 +/−2.7 °Mechanical lateral distal femoral angle changed an average 7 +/− 7.72 degrees. Medial proximal tibial angle changed an average 4 +/− 6.02 degrees. Complications necessitating surgery occurred in 2.8% of cases (1 wound infection, 3 corrective osteotomies following overcorrection).

Conclusion

Temporary hemiepiphysiodesis using eight-Plates is a gentle, simple and effective procedure used to treat genu valgum by modulating growth. Slight overcorrection is desirable due to the rebound phenomenon, especially in young patients with high growth potential and risk groups such as obese children. In adolescents with only low growth potential (older than 14 years), owing to the low correction potential, the indication should be strictly reviewed and the possible failure of therapy should be discussed with the patient. No differences were observed regarding the location of the implanted eight-Plates (femoral or tibial).

Determining the best treatment for coronal angular deformity of the knee joint in growing children: a decision analysis

This study aimed to determine the best treatment modality for coronal angular deformity of the knee joint in growing children using decision analysis. A decision tree was created to evaluate 3 treatment modalities for coronal angular deformity in growing children: temporary hemiepiphysiodesis using staples, percutaneous screws, or a tension band plate. A decision analysis model was constructed containing the final outcome score, probability of metal failure, and incomplete correction of deformity. The final outcome was defined as health-related quality of life and was used as a utility in the decision tree. The probabilities associated with each case were obtained by literature review, and health-related quality of life was evaluated by a questionnaire completed by 25 pediatric orthopedic experts. Our decision analysis model favored temporary hemiepiphysiodesis using a tension band plate over temporary hemiepiphysiodesis using percutaneous screws or stapling, with utilities of 0.969, 0.957, and 0.962, respectively. One-way sensitivity analysis showed that hemiepiphysiodesis using a tension band plate was better than temporary hemiepiphysiodesis using percutaneous screws, when the overall complication rate of hemiepiphysiodesis using a tension band plate was lower than 15.7%. Two-way sensitivity analysis showed that hemiepiphysiodesis using a tension band plate was more beneficial than temporary hemiepiphysiodesis using percutaneous screws.

Guided growth by a stainless-steel tubular plate

Guided growth using titanium tension band plates is an advancement in the correction of angular deformity. We applied two-hole stainless-steel one-third tubular plates for the same purpose. There were 14 deformities around the knees in eight children, mean age 10.8 years at operation. The success rate was 92.9% (13/14). The average correction rate per month was 0.59° in the femur and 0.65° in the tibia. No premature physeal arrest, overcorrection, or rebound phenomenon was observed. A stainless-steel plate is a safe and effective option for guided growth surgery in countries where only stainless-steel plates are available.

Distal tibial physeal bridge: a complication from a tension band plate and screw construct. Report of a case

We report on a case of a tension band plate and screw construct (Eight Plate) used over the anterior distal tibia in an 9-year-old girl in an attempt to induce recurvatum of the ankle joint to correct a recalcitrant equinus deformity. With growth of the distal tibial physis, the epiphyseal screw was drawn through the physis into the distal tibial metaphysis, resulting in the creation of a transphyseal bony bar. Caution should be exercised when attempting temporary hemiepiphyseodesis using a plate and screw construct in small epiphyses or in an osteopenic bone.

A technical note on improved instrumentation for Blount staple insertion

PURPOSE

Temporary hemiepiphysiodesis has gained increasing popularity after the introduction of the eight-Plate Guided Growth System. Since its introduction, the eight-Plate has largely supplanted the traditional Blount staple. The eight-Plate offers better purchase in the bone and a more precise insertion technique. However, the Blount staple is less expensive than the various guided growth plates. Further, some surgeons feel that the Blount staple may work faster, making it more appropriate for children who are approaching skeletal maturity. Unfortunately, the original instrumentation and technique for inserting the Blount staple is over 50 years old and has not been updated.

METHODS

The purpose of this study was to develop new instrumentation to make Blount staple insertion as accurate and minimally invasive as eight-Plate insertion. We developed wire/drill guides to accommodate all three sizes of the Blount staple. Two wires are inserted through the wire guide under image intensifier control. After confirming the accurate position of the guidewires, a 3.2-mm cannulated step drill is used to drill over the wires to a depth of 5 mm. This creates two pilot holes for the two tines of the Blount staple. The final insertion is guided under an anteroposterior image intensifier view. We also developed a small staple holder that permits insertion through a small incision.

RESULTS

We developed a working prototype of the new instrumentation and used it in three clinical cases.

CONCLUSIONS

With the new staple inserter and instrumentation, Blount staples can now be inserted through a smaller incision with similar accuracy as eight-Plate insertion.

Angular deformity correction by asymmetrical physeal suppression in growing children: stapling versus percutaneous transphyseal screw

PURPOSE

The aim of this study was to compare the outcomes of angular deformity correction by hemiepiphyseal stapling versus percutaneous hemiepiphysiodesis using transphyseal screw in growing children.

METHODS

Forty-three physes in 19 patients underwent hemiepiphyseal stapling, and 37 physes in 23 patients underwent percutaneous transphyseal screw placement. All cases were followed up to skeletal maturity or for more than 1 year after hardware removal. Amounts and rates of angular deformity correction, physeal behaviors after hardware removal, and postoperative courses were compared between the 2 groups.

RESULTS

The goal of angular correction was achieved in all except 2 patients, who reached skeletal maturity precociously. The mean rates of angular correction were not significantly different between the 2 groups, in both distal femur and proximal tibia. Hardware was removed before skeletal maturity from 56 physes. Angular change remained within 3 degrees for 43 physes (76.8%) at more than 1 year postoperatively, and the rebound phenomenon was observed in 12 (21.4%). No significant difference was observed between the 2 groups in terms of physeal behavior after hardware removal. Patients in the screw group were administered less postoperative pain medication, had shorter hospital stays, and smaller operation scars. In the stapling group, 1 case was complicated due to an extruded staple, and another case experienced premature physeal arrest at 1.5 years postoperatively. One case in the screw group experienced correction failure, probably because of a technical error during screw placement.

CONCLUSIONS

Hemiepiphysiodesis using percutaneous transphyseal screw is as effective as hemiepiphyseal stapling in terms of angular deformity correction. Furthermore, hemiepiphysiodesis using transphyseal screw has the advantage of being a minimally invasive procedure, and in this series, did not cause permanent physeal arrest.

LEVEL OF EVIDENCE

Level III.

Temporary hemiepiphysiodesis with the eight-Plate for angular deformities: mid-term results

BACKGROUND

Angular deformities can be treated with corrective osteotomies and application of internal or external fixation. In children, this major intervention can be avoided with temporary hemiepiphysiodesis (i.e., guided growth). Recently, a new device called the eight-Plate Guided Growth System, consisting of a two-hole plate and two screws, was presented as an alternative to the widely used Blount staple to perform temporary hemiepiphysiodesis in children.

METHODS

Forty-three patients (54 physes, 51 limbs) underwent treatment between August 2004 and December 2005 with average follow-up after plate insertion of 2 years 2 months (range, 1 year 6 months to 2 years 6 months). Rate of correction and reversibility of this intervention were calculated.

RESULTS

Average age at eight-Plate implantation was 9 years 7 months (age range, 4 years 0 months to 14 years 3 months). eight-Plates were inserted for an average 14.2 months (range, 5.0-27.4 months). No growth disturbance was observed. Mechanical lateral distal femoral angle changed an average 10.00 degrees (range, 1-18 degrees) or 0.65 degrees/month (range, 0.05-1.22 degrees/month). Medial proximal tibial angle changed an average 7.78 degrees (range, 0-14 degrees) or 0.58 degrees/month (range, 0.13-1.67 degrees/month). In the two distal tibial cases, lateral distal tibial angle improved 6 degrees and 10 degrees (average change, 0.44 degrees/month). Mechanical axis deviation improved an average 25.4 mm (range, 0-74 mm) or 1.73 mm/month (range, 0-6.4 mm/month). Ten patients (13 limbs) had more than 10 months of radiographic follow-up after plate removal; ten limbs showed average rebound of 15.7 mm or 1.0 mm/month, indicating the reversibility of this procedure. Four cases failed to achieve correction.

CONCLUSIONS

The eight-Plate effectively treats angular deformities in growing children and is less likely to extrude spontaneously than the Blount staple. We have not observed growth disturbance or other complications related to this device.

Temporary hemiepiphyseal arrest using a screw and plate device to treat knee and ankle deformities in children: a preliminary report

PURPOSE

Traditionally, angular deformities are treated by means of osteotomy. In patients who are skeletally immature, this major intervention can be avoided by influencing or guiding the growth of the affected physis. Recently, a new device was presented as an alternative to the widely used Blount staple. Stevens developed a technique using a two-hole, non-locking plate with two screws to perform temporary hemiepiphysiodesis in children. We studied the effectiveness of this new device in correcting angular deformities in children even younger than 5 years of age.

METHODS

We evaluated our first series of 11 patients (17 eight-Plates) who underwent treatment for angular deformities of various origins and were followed to completion of correction. The average age at hemiepiphysiodesis was 10 years and 2 months (age range 4 years and 11 months-13 years and 8 months). The device was inserted in the lateral distal femur (two cases), the medial distal femur (eight cases), the lateral proximal tibia (two cases), the medial proximal tibia (four cases), and the medial distal tibia (one case).

RESULTS

The eight-Plate was inserted for an average of 9.5 months (range 5-13 months). The joint orientation angles and the mechanical axis improved in all patients, with the exception of one 13-year and 8-month-old boy with a resected osteosarcoma and a compromised growth plate. In valgus cases (12 limbs, 13 eight-Plates), the mechanical axis deviation improved by an average of 30.7 mm (range 13-55 mm). In varus cases (four limbs, four eight-Plates), the mechanical axis deviation improved by an average of 38.8 mm (range 0-74 mm). No hardware failures, extrusion, growth arrest, or other complications were observed. None of our patients required an osteotomy or repeat eight-Plate insertion.

CONCLUSIONS

We consider the eight-Plate to be an ideal tool for treatment of angular deformities in growing children. It allows for precise insertion and is reliable. It is also less likely to extrude like the Blount staple.