Accurate Deformity Correction Research Articles

Pertrochanteric Nonunion: When and Why to Consider a Medullary Implant.

Pertrochanteric nonunion management is a technically challenging problem. When repair is undertaken rather than conversion arthroplasty, successful treatment revolves around accurate deformity correction, preservation of vascularity, and stable durable fixation. The decision to use an extramedullary or intramedullary implant should be influenced by nonunion-specific characteristics and patient-related conditions. Failure to understand these nuances when selecting an implant strategy often results in treatment failure. The primary purpose of this article was to discuss these variables and delineate when an intramedullary implant should be considered for treatment of a pertrochanteric nonunion. The secondary purpose was to describe the author's preferred surgical technique for implant-driven deformity correction and compression when choosing an intramedullary nail.

NEUTRAL WEDGE DISTAL FEMORAL OSTEOTOMY (NWDFO) FOR CORRECTION OF LARGE VALGUS AND VARUS DEFORMITIES: TECHNIQUE AND RESULTS

IntroductionAngular deformities of the distal femur can be corrected by opening, closing and neutral wedge techniques. Opening wedge (OW) and closing wedge (CW) are popular and well described in the literature. CW and OW techniques lead to leg length difference whereas the advantage of neutral wedge (NW) technique has several unique advantages. NW technique maintains limb length, wedge taken from the closing side is utilised on the opening side and since the angular correction is only half of the measured wedge on either side, translation of distal fragment is minimum. Leg lengths are not altered with this technique hence a useful technique in large deformities. We found no reports of clinical outcomes using NW technique. We present a technique of performing external fixator assisted NW correction of large valgus and varus deformities of distal femur and dual plating and discuss the results.Materials & MethodsWe have treated 20 (22 limbs – 2 patients requiring staged bilateral corrections) patients for distal femoral varus and valgus deformities with CWDFO between 2019 and 2022. Out of these 4 patients (5 limbs) requiring large corrections of distal femoral angular deformities were treated with Neutral Wedge (NW) technique. 3 patients (four limbs) had distal femoral valgus deformity and one distal femoral varus deformity. Indication for NW technique is an angular deformity (varus or valgus of distal femur) requiring > 12 mm opening/closing wedge correction. We approached the closing side first and marked out the half of the calculated wedge with K – wires in a uniplanar fashion. Then an external fixator with two Schanz screws is applied on the opposite side, inserting the distal screw parallel to the articular surface and the proximal screw 6–7 cm proximal to the first pin and at right angles to the femoral shaft mechanical axis. Then the measured wedge is removed and carefully saved. External fixator is now used to close the wedge and over correct, creating an appropriate opening wedge on the opposite side. A Tomofix (Depuoy Synthes) plate is applied on the closing side with two screws proximal to osteotomy and two distally (to be completed later). Next the osteotomy on the opposite side is exposed, the graft is inserted. mLDFA is measured under image intensifier to confirm satisfactory correction. Closing wedge side fixation is then completed followed by fixation of opposite side with a Tomofix or a locking plate.Results3 patients (4 limbs) had genu valgum due to constitutional causes and one was a case of distal femoral varus from a fracture. Preoperative mLDFA ranged from 70–75° and in one case of varus deformity it was 103°. We achieved satisfactory correction of mLDFA in (85–90°) in 4 limbs and one measured 91°. Femoral length was not altered. JLCA was not affected post correction. Patients were allowed to weight bear for transfers for the first six weeks and full weight bearing was allowed at six weeks with crutches until healing of osteotomy. All osteotomies healed at 16–18 weeks (average 16.8 weeks). Patients regained full range of movement. We routinely recommend removal of metal work to facilitate future knee replacement if one is needed. Follow up ranged from 4 months to 2 yrs. Irritation from metal work was noted in 2 patients and resolved after removing the plates at 9 months post-surgery.ConclusionsNWDFO is a good option for large corrections. We describe a technique that facilitates accurate correction of deformity in these complex cases. Osteotomy heals predictably with uniplanar osteotomy and dual plate fixation. Metal work might cause irritation like other osteotomy and plating techniques in this location.

Treatment of Severe Genu Valgum Deformity Secondary to Renal Osteodystrophy by Medial Close Wedge Osteotomy using an Innovative Trigonometric Technique of Wedge Calculation

Genu valgum is one of the most common deformity of the knee in which the knee bend toward the midline with increase in the intermalleolar distance. It is often treated surgically with the osteotomy or by growth modulation techniques such as hemiepiphysiodesis using bone staplers. We, hereby, present a case of 16-year-old female with severe genu valgum deformity of bilateral lower limbs secondary to renal osteodystrophy causing pain in her bilateral lower limbs and inability to walk. She was treated by McEwan’s close wedge osteotomy using an innovative trigonometric-based technique for calculation of wedge size which resulted in accurate correction of deformity. Keywords: Genu valgum, Renal osteodystrophy, Medial close wedge osteotomy, Trigonometric method of wedge calculation.

Limb Deformity Correction Using the Ortho SUV Frame

Background and Objective. Limb deformity in terms of length discrepancy, angular and rotational deformities are amenable to correction using the Ilizarov method. The corrections can be achieved using the Ortho SUV Frame (OSF), a computer assisted six axes external fixator. Previous studies have reported easier and more accurate deformity correction. In this study, we report on our initial experience and treatment outcomes in using this system.
 Materials and Methods. This study is a case series of patients where the Ilizarov circular frame was applied and which the deformity correction was carried out using the OSF. Success and accuracy in correction, length of time to correct, number of revisions needed and complications were gathered from a review of medical records.
 Results. Thirty limbs in twenty nine cases were included in this report. Seventy seven percent (23/30) of the deformities were due to previous trauma. The rest were due to Blounts, infection and tumor. Correction in eighty seven percent (26/30) were achieved using the turning schedule provided by the Ortho SUV application software. Three cases required surgical removal of soft tissue interposition before further correction using the software was achieved. One case with posterior translation underwent closed manipulation. In the end all planned deformity corrections were achieved. Complications included pin tract swelling and erythema in 13% and all resolved either with oral antibiotics alone or combined with surgical release of pin sites under local anesthesia.
 Conclusion. The Ortho SUV is an effective tool to carry out deformity corrections using the Ilizarov method.

Distance from the magnification device contributes to differences in lower leg length measured in patients with TSF correction

IntroductionIn absence of deformity or injury of the contralateral leg, the contralateral leg length is used to plan limb lengthening. Length variability on long-leg weight-bearing radiographs (LLR) can lead to inaccurate deformity correction. The aim of the study was to (1) examine the variability of the measured limb length on LLR and (2) to examine the influence of the position of the magnification device.Materials and methodsThe limb lengths of 38 patients during deformity correction with a taylor-spatial-frame were measured retrospectively on 7.3 ± 2.6 (4–13) LLR per patient. The measured length of the untreated limb between LLR were used to determine length variability between LLR in each patient. To answer the secondary aim, we took LLR from a 90 cm validation distance. A magnification device was placed in different positions: at the middle of the 90 cm distance (z-position), 5 cm anterior and 5 cm posterior from the z-position, at the bottom and top of the validation distance as well as 5 cm medial and 15 cm lateral from the z-position.ResultsThe measured length variability ranged within a patient from 10 to 50 mm. 76% of patients had a measured limb length difference of ≥ 2 cm between taken LLR. Compared to length measurement of the 90 cm test object with the magnification device in the z-position (90.1 cm), positioning the device 5 cm anterior led to smaller (88.6 cm) and 5 cm posterior led to larger measurements (91.7 cm). The measured length with the magnification device at the bottom, top, medial or lateral (90.4; 89.9; 90.2; 89.8 cm) to the object differed not relevantly.ConclusionsHigh variability of limb length between different LLR within one patient was observed. This can result from different positions of the magnification device in the sagittal plane. These small changes in positioning the device should be avoided to achieve accurate deformity correction and bone lengthening. This should be considered for all length and size measurements on radiographs.

Corrective osteotomy for hyperextended elbow with limited flexion due to supracondylar fracture malunion

Extension deformity of the distal humerus after a malunited supracondylar fracture can restrict elbow flexion. Here we report a computer-assisted operative procedure and review the results of clinical cases in which corrective surgery was performed. The medical records of the patients who underwent corrective osteotomy for hyperextended elbow malunion of the distal humerus with limited elbow flexion (flexion angle ≤100°) were reviewed retrospectively. Osteotomy was performed using patient-specific instruments designed based on preoperative 3-dimensional computer simulation. Three patients, a 55-year-old woman and two 12-year-old boys, met the inclusion criteria. The angles of hyperextension of the affected distal humerus were 29°, 29°, and 25°, respectively. The range of flexion/extension of the elbow motion in the first patient improved from 95°/25° preoperatively to 140°/-10° postoperatively, in the second patient from 100°/20° to 145°/5°, and in the third patient from 80°/25° to 140°/10°. Bone union was achieved in all patients. There were no major complications. The corrective operations not only improved elbow flexion but also increased the total range of motion in the elbow by rebuilding the anterior curve of the distal humerus. Correction of the extension deformity of the distal humerus after a malunited supracondylar fracture is a reasonable option for patients older than 10 years with restricted elbow flexion. Preoperative computer simulation and the use of patient-specific instruments can be a useful alternative that enables accurate deformity correction and improves the total range of motion.

Acute correction of proximal tibial varus deformity in adolescent Blount disease with a low-profile Ilizarov frame

Background: Adolescent tibia vara usually presents with genu varum deformity and is commonly associated with internal tibial torsion. The Ilizarov technique is one of the accepted techniques for correction of this deformity. Acute correction has the advantage of a shorter duration in the fixator and less patient discomfort. Using the Ilizarov construct with two rings decreases bulkiness of the frame and improves compliance. Methods: Thirteen male patients with adolescent Blount disease, seven of whom had bilateral deformities (total 20 knees), were managed by extra-focal tibial valgus lateral translation osteotomy with a low- profile Ilizarov frame fixation. The frame was removed after full union, and patients were followed-up for 18 mo. Patients were assessed clinically using intercondylar distance and radiographically by measuring the distal lateral femoral angle and proximal medial tibial angle on CT scanogram. Results: All patients achieved correction of the tibial varus deformity. The intercondylar distance improved from 12.1 cm on average preoperatively to 5 cm on average postoperatively. The mean preoperative deviation of the medial proximal tibial angle was 22 degrees while the mean postoperative deviation was 2.4 degrees (ranging from 0-8.5 degrees). The mean duration to union of the osteotomy was 9 wk (range, 7-10 wk). Pin track infection occurred in 8 limbs. Conclusions: Extra-focal percutaneous valgus lateral translation osteotomy and fixation with a low-profile Ilizarov frame allows accurate deformity correction, shorter duration in the fixator, and better patient comfort and satisfaction.

Lengthening of the Femur with a Remote-Controlled Magnetic Intramedullary Nail: Retrograde Technique.

Femoral lengthening with an intramedullary nail inserted through a retrograde approach offers the unique benefit of accurate deformity correction and distraction osteogenesis without the need for external fixation with its inherent challenges. The key to a successful deformity correction and proper nail placement is preoperative planning. Insert 2 Steinmann pins or half-pins into the proximal and distal aspects of the femur to mark any rotational deformity that is being corrected or to ensure that no rotational deformity is created. The Steinmann pins need to be ≥3 mm in diameter to prevent bending with loss of rotational reference. We prefer 5-mm or 6-mm Schanz pins for this role. These sturdy pins may be used as a "joystick" for manipulating the distal fragment to achieve a correction. This step includes the approach to and reaming of the distal fragment, which is critical to the limb alignment. Perform the percutaneous osteotomy, which allows for correction of the deformity, prior to reaming the proximal segment. While holding the distal fragment in the reduced position, prepare the proximal fragment for nail insertion. Insert the nail in a standard fashion, avoiding excessive force that could damage it or jam it into the proximal fragment. Lock the nail from the distal or proximal end first. The femoral distractor helps to keep the rotation accurate during locking and helps to serve as a handle to obtain perfect overlapping circles of the locking screw site on fluoroscopy. However, the external fixator may be obstructive for distal locking in particular. The fixator can be removed for distal locking and reattached for proximal locking. Check the anteroposterior and lateral fluoroscopic images and decide how stable the nail is in the bone. Will the fragment shift into varus, valgus, or flexion? Mark the position and orientation of the magnet in the nail on the patient's skin to indicate where to place the external magnet for lengthening. Postoperative management involves nail distraction, venous thromboembolic (VTE) prophylaxis, and adherence to a specific weight-bearing protocol. Femoral lengthening with the remote-controlled magnetic intramedullary nail has had excellent clinical efficacy3.

Femoral lengthening and deformity correction using the Fitbone motorized lengthening nail.

BackgroundThis study reports our results with retrograde Fitbone insertion in patients with femoral shortening and deformity. We also present our experience regarding the benefits, complications, and factors associated with complications of the Fitbone technique.MethodsTwelve males and ten females had femoral shortening and deformities treated using the retrograde Fitbone technique between 2009 and 2012. The etiologies were post-traumatic in 12 patients, poliomyelitis in four, cosmetic in two, congenital hypoplasia in two, achondroplasia in one, and Perthes sequela in one.ResultsThe follow-up time was 30.8 months. The mean lengthening was 5.8 (range 2–14) cm. The degree of acute angular correction was 9° (5–22°) in nine cases. The time to full weight-bearing was 5.9 months. The consolidation index was 1.07 (0.75–1.62) months/cm. Complete consolidation was obtained in all cases except two. Running back was observed in two cases.ConclusionsThe Fitbone technique allows accurate deformity correction. The rigid reamers allow the surgeon to use the Fitbone even in patients with a narrow medullary canal. As this might result in poor bone regeneration, thinner lengthening nails should be considered.

Computer-assisted osteotomy for valgus knees: Medium-term results of 29 cases

IntroductionComputer-assisted surgery has been shown to be beneficial for correcting misaligned lower limbs. The purpose of this study was to analyze the medium-term results of computer-assisted osteotomy for 29 valgus knees. The hypothesis was that computer navigation would allow a valgus deformity to be corrected with similar precision as varus deformity. Material and methodsThe series consisted of 27 patients (29 knees); there were 7 men and 20 women with ages ranging from 15 to 63 years (mean: 42.4±14.3 years). Twenty-four varus osteotomies of the femur (14 medial closing and 10 lateral opening) and five double osteotomies (proximal tibia and distal femur) were performed. The pre-operative functional status was evaluated with the Lysholm-Tegner score. The mean score was 64±20.5 points (range: 18–100). According to Ahlbäck's modified classification for knee osteoarthritis, 12 patients were at stage 1, nine were at stage 2, five at stage 3 and one at stage 4. Two of the knees had no radiological signs of osteoarthritis but had a particularly unsightly deformity; one of these was secondary to high tibial valgus osteotomy. The mean pre-operative hip-knee-angle (HKA) angle was 189.3±3.9°; the mean mechanical medial distal femoral angle (mMDFA) was 97.2±2.6° and mechanical medial proximal tibial angle (mMPTA) was 90.1±2.8°. The goal was to achieve an HKA angle of 179±2° and mMPTA of 90±2° to avoid an oblique joint line. Functional outcomes were evaluated with the Lysholm-Tegner, KOOS and IKS scores. ResultsNo complications other than a transient paralysis of the common fibular nerve were observed. Twenty-three patients (25 knees) were reviewed at a mean follow-up of 50.9±38.8 months (range: 6–144). The mean Lysholm-Tegner score was 92.9±4 points (86–100), the mean KOOS was 89.7±9.3 (range: 68–100), the mean IKS “knee” score was 88.7±11.4 points (range: 60–100) and the “function” score was 90.6±13.3 points (range: 55–100). Twenty-two patients were satisfied or very satisfied. The mean HKA angle was 180.1±1.9°, the mean mMDFA 90.7±2.5° and the mean mMPTA 89.1±1.9°. The pre-operative goal was achieved in 86.2% of cases (25/29) for the HKA angle and 100% of cases of the mMPTA angle. At the follow-up, none of the knees had been revised with a prosthesis. ConclusionComputer-assisted osteotomy for cases of osteoarthritis secondary to valgus knee leads to excellent medium-term results. Navigation provides reliable and accurate deformity correction. Level of evidenceIV. Retrospective study.

Bone realignment with use of temporary external fixation for distal femoral valgus and varus deformities.

Correction of a distal femoral deformity may prevent or delay the onset of osteoarthritis or mitigate its effects. Accurate correction of deformity without production of a secondary deformity depends on precise localization and quantification of the deformity. We report a technique to correct distal femoral deformities in the coronal plane. Fourteen femora in thirteen skeletally mature patients with a distal femoral deformity underwent operative reconstruction. The preoperative deviation of the mechanical axis ranged from 90 mm laterally (genu valgus) to 120 mm medially (genu varus). The mechanical lateral distal femoral angle was abnormal in all fourteen knees. The technique consisted of application of an external fixator, performance of a percutaneous distal femoral dome osteotomy, correction of the deformity, and locking of the external fixator. A statically locked retrograde intramedullary nail was inserted following reaming, and the external fixator was removed. The mean duration of follow-up was thirty-three months (range, six to forty-seven months). The mean time until healing was thirteen weeks (range, six to thirty-nine weeks). Nine of the thirteen patients reported an improvement in walking, and none needed an assistive device. All nine patients with preoperative knee pain were free of tibiofemoral pain at the most recent follow-up evaluation. The mechanical lateral distal femoral angle was within the normal range in twelve of the fourteen knees. The mechanical axis was within the normal range in ten lower extremities. In three of the four remaining limbs, the residual abnormal deviation of the mechanical axis was due to a residual tibial deformity. Percutaneous dome osteotomy combined with temporary external fixation and insertion of an intramedullary nail can correct distal valgus and varus femoral deformities. We attributed the early mobilization of patients and the rapid bone-healing to the limited soft-tissue dissection, the low-energy corticotomy, and the use of intramedullary fixation in our surgical technique.