Pedicled Rotational Medial and Lateral Gastrocnemius Flaps: Surgical Technique

Proceedings of the United Kingdom Periprosthetic Joint Infection Meeting 2022: Combined and Arthroplasty Sessions

Considerable variation in practice exists in the prevention, diagnosis, and treatment of periprosthetic joint infection (PJI), which is a devastating complication for patients and surgeons. The consensus principle has been increasingly embraced by the orthopaedic community to help guide practice, especially where high-level evidence remains unavailable. The third United Kingdom Periprosthetic Joint Infection (UK PJI) Meeting was held in Glasgow on April 1, 2022, with more than 180 delegates in attendance, representing orthopaedics, microbiology, infectious diseases, plastic surgery, anesthetics, and allied health professions, including pharmacy and arthroplasty nurses. The meeting comprised a combined session for all delegates, and separate breakout sessions for arthroplasty and fracture-related infection. Consensus questions for each session were prepared in advance by the UK PJI working group, based upon topics that were proposed at previous UK PJI Meetings, and delegates participated in an anonymized electronic voting process. We present the findings of the combined and arthroplasty sessions of the meeting in this article, and each consensus topic is discussed in relation to the contemporary literature.

Ankle function after reconstruction of post-traumatic soft tissue defects with soleus and/or gastrocnemius local muscle flaps

Local muscle flaps are especially advantageous when treating soft tissue defects, but one disadvantage is the potential functional deficits associated with the muscle transfer. In this study, we evaluated ankle function among patients (cases) who underwent reconstruction of soft tissue defects in the leg using local flaps of the gastrocnemius and/or soleus muscle. Function was compared between the affected and contralateral non-affected limb and against patients (controls) with open tibial fractures who required no soft tissue reconstruction. In a retrospective cohort study, ankle function was accessed as range of motion (ROM) and plantar flexion strength, and using American Orthopaedic Foot and Ankle Society (AOFAS) ankle-hindfoot summation and subscale scores. Among 31 patients who underwent soft-tissue reconstruction, 19 were available for functional evaluation. Controls were 23 patients with open tibial fractures not requiring flaps. Among cases, reconstruction was performed with a soleus flap in nine patients, a medial gastrocnemius flap in seven, a lateral gastrocnemius in one, and with both gastrocnemius and soleus flaps in one patient each. One patient developed partial flap necrosis. In cases, ankle dorsiflexion and plantar flexion were significantly decreased on the affected versus normal side. However, no deficit in plantar flexion strength was detected; nor any significant difference in AOFAS ankle-hindfoot scores in cases versus controls. Local muscle flaps are useful for reconstructing post-traumatic soft tissue defects in the leg. Some loss of ankle ROM should be expected, but likely no clinically-measurable deficit in overall ankle strength and function.

Reconstruction of soft tissue defect around knee with thoracodorsal artery perforator flap and muscle-sparing latissimus dorsi flap

INTRODUCTION

Around the knee reconstruction is challenging for reconstructive surgeons. Several methods have been proposed, including perforator and muscle flaps; however, all have advantages and disadvantages. As the success rate of free-flap surgery increases, reconstruction around the knee using this method is becoming increasingly popular. Nevertheless, there are no large-scale case reports in the previous literature using either a thoracodorsal artery perforator flap (latissimus dorsi (LD) perforator flap) or a muscle-sparing latissimus dorsi (msLD) flap for reconstruction around the knee. In this retrospective report, we describe our clinical experiences and present an algorithm regarding recipient vessel choice in free-flap reconstructive surgery of around the knee defects.

PATIENT AND METHODS

Fifty-six cases in which a flap from the lateral thoracic area was used to reconstruct an around the knee defect between January 2016 and March 2022 were reviewed. The patients were aged 18-87 years (mean, 52.13 years), and of the 56 patients, 36 were male and 20 were female. Injuries were caused by trauma, contracture, rheumatoid vasculitis, tumor, infection, burns, sunken deformity, and pressure sores. The 56 cases included 22 with a defect including the knee, 14 with a defect below the knee (7 of the primary below-knee amputation [BKA] and 7 of the secondary BKA), 9 involving the distal medial thigh, 8 involving the distal lateral thigh, 2 involving the popliteal area, and 1 involving the middle thigh. Most cases were reconstructed using a single LD perforator flap or msLD flap. Chimeric or supplementary flaps were used when extensive coverage or dead space obliteration was required. The average size of the defect area was 253.6 cm2 (range: 5 × 6-21 × 39 cm2 ).

RESULTS

In the cases, the recipient artery used included the following: descending genicular artery (23), superficial femoral artery (14), descending branch of the lateral circumflex femoral artery (14), anterior tibial artery (2), popliteal artery (2), and posterior tibial artery (1). The recipient vein included the greater saphenous vein (24), descending branch of the lateral circumflex femoral vein (14), superficial femoral vein (7), descending genicular vein (6), anterior tibial vein (2), popliteal vein (2), and posterior tibial vein (1). The average flap size was 281.8 cm2 (range: 4 × 8-35 × 19 cm2 ). All flaps survived; however, seven complications occurred, including 2 partial flap losses, 1 arterial insufficiency, 1 hematoma, 1 minor dehiscence, 1 donor-site graft loss, and 1 short BKA. Normal knee range of motion (121-140°) was observed in 34 patients and 16 showed varying degrees of limited range of motion. Motion was not observed in four patients who underwent knee fusion and could not be evaluated in two patients who underwent above-knee amputation. The mean follow-up duration was 24.6 months (range: 4-72 months).

CONCLUSION

The LD perforator flap is ideal for the reconstruction of around the knee defects because it enables a long pedicle, large flap, and chimeric design. The msLD flap is ideal because it enables strong stump support, dead-space obliteration, and infection control. Moreover, since the two flaps are distant from the knee, this method is advantageous in terms of postoperative rehabilitation and there is minimal donor-site morbidity due to the thin nature of the LD muscle. In addition, the flap can be elevated in three positions and the operation can be completed without positional changes in various recipient vessel locations. Based on our experience, we conclude that the LD flap has the potential to be used as widely as or in preference to the anterolateral thigh flap in the reconstruction of around the knee defects.

How to get the most out of your gastrocnemius and soleus flaps

Gastrocnemius and soleus flaps represent the workhorse local flaps to cover soft tissue defects of the proximal 1/3 and middle 1/3 of the leg, respectively. An important consideration before conducting a local flap is whether the flap can provide adequate coverage. The utility of the gastrocnemius flap can be increased using multiple techniques to increase the arc of rotation including the posterior midline approach, dissection at the pes anserinus and medial femoral condyle origin, scoring the fascia, and inclusion of a skin paddle. Concerning the soleus flap, the hemisoleus flap represents a technique to increase the arc of rotation. With a soleus flap, one must consider the soft tissue defect location, size, and perforator blood supply because these factors influence what soleus flap technique to use. This article discusses how to make the most out of gastrocnemius flaps and soleus flaps regarding maximizing coverage and ensuring successful flap outcome.

Medial gastrocnemius rotational flap for the reconstruction of extensor mechanism disruption in periprosthetic knee infections: a retrospective series with minimum two year follow-up

PURPOSE

Extensor mechanism disruption following total knee arthroplasty has a prevalence ranging from 0.3 to 3%. Its management is challenging, especially in case of associated infection of the prosthetic implant. Surgical options are limited due to the septic process, and the use of allograft or synthetic mesh are not recommended. The aim of this study was to report clinical outcomes, complications, survival, and surgical technique of medial gastrocnemius flap for the treatment of extensor mechanism disruptions associated with periprosthetic knee infection.

METHODS

This is a retrospective study from a prospectively collected arthroplasty registry from 2012 to 2019. Patients who received the gastrocnemius flap in the setting of a two-stage knee replacement for periprosthetic infection were included. Results of physical examination, Knee Society Score, Oxford Knee Score, and measurement of the range of motion registered pre-operatively were compared to those obtained at last follow-up. Survival was analysed through Kaplan-Meier curve.

RESULTS

A total of 15 patients were included, with a mean age of 63.4 years (range 36-77). The reconstruction of the extensor mechanism demonstrated a success rate of 73.3%. The mean extension lag at final follow-up was 7.5° (range, 0-30). The mean Knee Society Score and Oxford Knee Score improved from 29.0 (range, 21-36) and 17.5 (range, 13-22) respectively, to 82.9 (range, 74-89) and 36.0 (range, 33-39).

CONCLUSION

Medial gastrocnemius rotational flap is a reliable option for joint and limb salvage in case of periprosthetic knee infection associated with wide soft tissue degeneration and extensor mechanism disruption. The technique and surgical protocol presented in this study are reproducible and guaranteed good clinical outcomes and infection control.

Autologous menisci-cruciate ligament composite as a flap for soft tissue reconstruction following malignant bone tumor resection around the knee

BACKGROUND

Despite significant improvements in oncological treatment, the management of soft tissue defects following malignant tumor resection remains challenging. We investigated whether autologous menisci and cruciate ligament, which are traditionally discarded, can be recycled as a supplemental flap in repairing soft tissue defects following malignant bone tumor resection and endoprosthetic reconstruction around the knee.

METHODS

Four knee specimens were dissected to provide a basis for the design of the menisci-cruciate ligament composite. Then, 40 patients with bone malignancies around the knee were enrolled and underwent reconstruction with free or vascularized composite following malignant tumor resection. The clinical, radiographic, and functional outcomes of this technique were evaluated in >1-year follow-up in each patient and compared with 87 patients who suffered from bone malignancies around the knee and were treated by limb salvage but without composite at our center over the same period. During the follow-up, a composite from one patient who underwent secondary amputation was retrieved and examined for in vivo remodeling.

RESULTS

Fourteen patients were treated with vascularized composite transfer (10 distal femurs and 4 proximal tibias) and 26 patients with free composite transfer (19 distal femurs and 7 proximal tibias). The composite can be used to cover the area of soft tissue defect from 22 to 48.38 cm² (34.67 ± 6.48 cm² ). With contrast-enhanced ultrasound, peripheral rim healing and dotted blood flow signal at the side of anastomosis were detected on a patient 16 months after free composite transfer. Gross macroscopic remodeling and histopathologic analysis of a retrieved composite also indicated good healing with surrounding tissues and living cells in the composite. The complications and oncologic outcomes were comparable between study and control cohorts, but better Musculoskeletal Tumor Society (MSTS) score for patients reconstructed with composite (26.68 vs. 25.66, p  = 0.004). Of note, MSTS score was higher for patients reconstructed with composite at distal femur subdivision compared with the same subdivision in the control cohort (26.97 vs. 25.90, p  = 0.009). No statically significant difference was noted in complications, oncologic, and functional outcomes for patients reconstructed with free or vascularized composite.

CONCLUSION

Autogenous menisci-cruciate ligament composite is an alternative option for soft tissue reconstruction. Either vascularized or free composite can be applied, depending on the size and localization of the defect.

A comparison of healing and complication rates between common flaps utilized in total knee arthroplasty: a review of the literature

Background

Flap reconstruction with perforator, fasciocutaneous, muscular, and/or free microvascular flaps is utilized to cover wound defects and improve vascularization and antibiotic/nutrient delivery. Flap use in revision procedures for total knee arthroplasty has been explored previously; however, current data are limited and studies comparing healing and complication rates between different flap types are lacking.

Methods

A literature review was performed using PubMed on 13 January 2022. Studies were included if they reported healing and complication rates for either gastrocnemius, rectus abdominis, latissimus dorsi, fasciocutaneous, chimeric, or gracilis flaps in the setting of revision total knee arthroplasty (TKA).

Results

The final cohort included gastrocnemius (n = 421, healing rate 73.8%, complication rate 59.9%), gracilis (n = 9, healing rate 93%, complication rate 55.6%), latissimus dorsi (n = 41, healing rate 67%, complication rate 46.3%), rectus abdominis (n = 3, healing rate 100%, complication rate 0%), fasciocutaneous (n = 78, healing rate 70%, complication rate 19.2%), and chimeric flaps (n = 4, healing rate 100%, complication rate 25%). There was no significant difference when comparing healing rates across flap types (p = 0.39). There was a significant difference when comparing complication rates across flap types (p < 0.0001), with a significant difference being noted between gastrocnemius and fasciocutaneous complication rates (p < 0.0001). All other comparisons between flap types by complication rate were not significantly different.

Conclusions

Gastrocnemius flaps are the workhorse flap in the setting of revision TKA, as evidenced by this review. Healing rates did not vary significantly across flap types, which suggests that determining the appropriate flap for coverage of soft-tissue defects in revision TKA should be driven by defect size and location as well as physician experience and patient tolerance.

Prediction of soft tissue coverage following distal femur bone sarcoma resection: A preliminary report

We aimed to examine the predictability of the need for soft tissue reconstruction during limb-sparing surgery through preoperative magnetic resonance (MR) imaging in patients diagnosed with a malignant bone tumor in the distal femur. The study included 42 patients who were operated for a bone sarcoma of the distal femur at our clinic between 2016 and 2018. The recorded parameters included the demographic characteristics of the patients, tumor diagnosis, tumor side, total tumor volume, tumor soft tissue component volume, tumor soft tissue component volume-to-total tumor volume ratio, tumor localization by MR imaging, the need for soft tissue reconstruction, the muscles used for soft tissue reconstruction, the biopsy site, and the biopsy type. Tumor volume was calculated on MR imaging of the distal femur region performed before surgery. Our study established cut-off values for soft tissue reconstruction need following resection as a total tumor volume of 96.4 cm³ , a tumor soft tissue component volume of 22 cm³ , a tumor soft tissue component volume-to-total tumor volume ratio of 48.9%, and tumor localization in two different regions on axial distal femoral MR images. Considering these cut-off values, by calculating tumor volume values preoperatively we can predict the need for rotational muscle flaps for soft tissue coverage following distal femur bone sarcoma resection and endoprosthesis reconstruction. Anticipating the need for soft tissue reconstruction may affect the duration and success of the operation.

Gastrocnemius pedicled muscle flap for knee and upper tibia soft tissue reconstruction. A useful tool for the orthopaedic surgeon

Soft tissue defect coverage has always been a challenge for the orthopaedic surgeon. Over the last decades the surgery of flaps has completely changed the prognosis for large defects. The purpose of this study is to retrospectively review our experience with the gastrocnemius muscle as pedicled local flaps for reconstruction of knee and upper third of the tibia soft tissue defects. Twenty-seven patients underwent reconstruction of soft tissue defects around the knee using pedicled gastrocnemius muscle flaps. There were eighteen men and nine women ranged in with a mean age of 50.3 years. Medial gastrocnemius was used in 21 cases, and lateral gastrocnemius in 5 cases. In one patient, soleus and medial gastrocnemius were transferred simultaneously. All but one had at the same time split thickness skin graft for coverage of the muscle. All muscle flaps transferred were successful. There were no complications and all flaps survived completely without vascular compromise, satisfactory coverage of the defect, and good primary wound healing. There has been no recurrence of osteomyelitis. The donor sites healed perfectly with no remarkable resultant functional disability. A mean follow-up of 4.4 years revealed acceptable cosmetic results with high patient satisfaction. Our results indicate that the gastrocnemius muscle transfer is a useful technique for coverage of soft tissue defects in the upper tibia and around the knee in our orthopaedic practice. It is a reliable option for the coverage of exposed bone, the filling up of deep cavities and the treatment of bone infection. The principal advantage of a muscle flap is to bring a real blood supply to the recipient site and to improve the trophicity of the surrounding tissues. The pedicled muscle flap is our preference for the management of soft tissue defects around the knee, when no other procedure, apart from free flap is suitable. The pedicle flap is easier, quicker and with less complications than a free flap. Orthopaedic surgery has gained much from the use of island flap, however, it requires knowledge of the vascular anatomy and its variations promoted through cadaveric dissections and flap dissection courses.

Tendon transfer for dysfunction of all tendons in leg excepting Achilles tendon and plantaris tendon following irreparable sciatic nerve palsy - A case report

INTRODUCTION AND IMPORTANCE

Irreparable sciatic nerve palsy is a cause of foot drop and resulting in absent or weak most of the muscles in leg. There may be dysfunctions of all tendons in the leg excepting Achilles tendon and plantaris tendon. The treatment of this atypical neurologic injury has not been defined.

CASE PRESENTATION

I reported a case of foot drop following irreparable sciatic nerve palsy in which there was a dysfunction of all tendons in leg excepting Achilles tendon and plantaris tendon. The medial gastrocnemius tendon and plantaris tendon were transferred into the anterior tibialis tendon, the extensor digitorum longus tendon and extensor hallucis longus tendon. The lateral gastrocnemius tendon was transferred into the peroneus brevis. Four months post-operative, he reported no pain and became capable of walking without the assistance of an orthosis or a crutch and without steppage gait.

CLINICAL DISCUSSION

Anterior transfer of the tibialis posterior tendon was the preferred procedure. If no posterior tibial tendon function was presented, then in order of preference, the extensor hallucis longus, extensor digitorum longus, peroneal, flexor hallucis longus tendon, medial gastrocnemius, lateral gastrocnemius and plantaris tendon would be used.

CONCLUSION

The atypical dysfunction of all tendons in the leg excepting Achilles tendon and plantaris tendon following irreparable sciatic nerve palsy was presented. Tendon transfer using medial gastrocnemius tendon, lateral gastrocnemius tendon and plantaris tendon seemed to be a good choice for treatment of this injury. It allowed reconstruction of a stable, painless, plantigrade foot.

LEVEL OF EVIDENCE

Case report.

Popliteal artery patency is an indicator of ambulation and healing after below-knee amputation in vasculopaths

BACKGROUND

The posterior flap is a conventional technique for closing a below-knee amputation (BKA) that uses the gastrocnemius and soleus muscle and relies on the popliteal and posterior compartment arteries. If the prior mentioned arterial blood supply is compromised, this flap likely relies on collateral flow. The purpose of this study is to identify and differentiate any significant associations between preoperative popliteal and tibial arterial flow and BKA outcomes and patient-reported function.

METHODS

A retrospective review identified patients from a single tertiary wound care center who received BKAs and angiogram between 2010 and 2017 by a single surgeon. BKA complications, wound healing, and amputee ambulatory status at latest follow-up were all stratified for differences according to baseline tibial vessel run-off (VRO) status, popliteal artery patency, and popliteal angioplasty outcome. Chi-square, Fisher's exact, and Wilcoxon rank sum tests were used with significance defined as p ≤ 0.05.

RESULTS

BKAs were performed on 313 patients, of which, 167 underwent preoperative angiography. Thirty-two were excluded due to lack of adequate follow-up leaving a total of 135 patients in the studied population. Diabetes was present in 87%, and 36% had end-stage renal disease. By the study's conclusion, 92% of BKAs had fully healed, with median time-to-healing of 79 days (range 19-1314 days). 60% of patients were ambulatory at 9.5 months. Higher VRO was associated with higher healing rates and lower complications and time-to-healing. The conversion rate of BKA to above-knee amputation (AKA) was 4%. Preoperative popliteal patency was associated with higher postoperative ambulation rates when compared to patients without popliteal flow preoperatively (patent: 71/109, 65%; occluded: 10/26, 40%; p = 0.02) and independently increased the likelihood of postoperative ambulation.

CONCLUSIONS

The posterior flap design for BKA works even in the setting of popliteal occlusion. Complication rates are higher in patients with more compromised blood flow, which may ultimately lead to AKA. Given poor ambulation rates in patients who undergo AKA, the results of this study should encourage surgeons to consider a more functional BKA, even in instances when the popliteal artery is occluded.

New Technique for the Proximal Leg Reconstruction: Medial Sural Artery-Based Cross-leg Flap

Reconstruction of the lower extremity, especially the proximal lower leg, is known to be a challenge for reconstructive surgeons. When there is extensive vascular damage, the use of local flaps and microsurgical methods will be limited, so there are few reconstructive options available. We want to define the use of medial sural artery-based cross-leg flap for the reconstruction of the proximal lower leg. A 51-year-old male had a soft tissue defect on the proximal leg region because of a gun-shot injury. We observed that there was no chance of a local flap as a result of CT angiography. We considered free flap to be risky because of extensive vascular damage and medial sural artery-based cross-leg flap was planned. 12*20-cm-sized medial sural artery-based cross-leg flap was elevated from the contralateral leg and adapted to the defect without tension. Medial sural artery-based flap is mostly used as a vascular island for the reconstruction of knee defects. However, its use as a cross-leg flap has not been found in the literature. We believe that it is a safe option to consider in challenging cases such as after flap failure or patients not suitable for a free flap.

Intra-articular Extraskeletal EWSR1-Negative NR4A3-Positive Myxoid Chondrosarcoma: A Case Report

CASE

Extraskeletal myxoid chondrosarcomas (EMCs) are rare soft-tissue malignancies. Intra-articular occurrence is even more rare. To our knowledge, this case is one of only 2 reported intra-articular EMC cases of the knee free of local recurrence and/or amputation at follow-up. This case is also distinctive for being fluorescence in-situ hybridization-negative for the typical EMC-balanced translocation t(9;22) which fuses EWSR1 with NR4A3, harboring instead a variant translocation resulting in fusion of NR4A3 with a less common gene fusion partner.

CONCLUSION

This is a unique case of intra-articular EMC of the knee with a rare molecular fingerprint and an unusually positive outcome.

Functional evaluation of triceps surae during heel rise test: from EMG frequency analysis to machine learning approach

Soleus muscle flap as coverage tissue is a possible surgical solution adopted to cover the wounds due to open fractures. Despite this procedure presents many clinical advantages, relatively poor information is available about the loss of functionality of triceps surae of the treated leg. In this study, a group of patients who underwent a soleus muscle flap surgical procedure has been analyzed through the heel rise test (HRT), in order to explore the triceps surae residual functionalities. A frequency band analysis was performed in order to assess whether the residual heads of triceps surae exhibit different characteristics with respect to both the non-treated lower limb and an age-matched control group. Then, an in-depth analysis based on a machine learning approach was proposed for discriminating between groups by generalizing across new unseen subjects. Experimental results showed the reliability of the proposed analyses for discriminating between-group at a specific time epoch and the high interpretability of the proposed machine learning algorithm allowed the temporal localization of the most discriminative frequency bands. Findings of this study highlighted that significant differences can be recognized in the myoelectric spectral characteristics between the treated and contralateral leg in patients who underwent soleus flap surgery. These experimental results may support the clinical decision-making for assessing triceps surae performance and for supporting the choice of treatment in plastic and reconstructive surgery. Graphical Abstract The Graphical abstract presents the scope of the proposed analysis of myoelectric signals of soleus and gastrocnemius muscles of patiens groups during Hell Rise Test, highlighting the applied methods and the obtained results.

The Ideal Location of the Lateral Hinge in Medial Closing Wedge Osteotomy of the Distal Femur: Analysis of Soft Tissue Coverage and Bone Density

BACKGROUND

Although an appropriate hinge position to prevent unstable lateral hinge fractures is well established in medial opening wedge high tibial osteotomy, the position during medial closing wedge distal femoral osteotomy has not been elucidated.

PURPOSE/HYPOTHESIS

The purpose was to evaluate the ideal hinge position that would prevent an unstable lateral hinge fracture during biplanar medial closing wedge distal femoral osteotomy based on soft tissue coverage and bone density around the hinge area. The hypothesis was that the ideal hinge position could be clarified by analyzing soft tissue coverage and bone density around the lateral hinge area.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 20 cadaveric knees (mean age, 70.3 ± 19.2 years), the femoral attachment of the gastrocnemius lateral head was quantitatively analyzed as a soft tissue stabilizer using digital photography and fluoroscopy. Then, medial closing wedge distal femoral osteotomy was performed, locating the lateral hinge either inside (group 1) or outside (group 2) the femoral attachment of the gastrocnemius lateral head, and the incidence of unstable lateral hinge fractures was compared between the 2 groups. Cortical bone density around the lateral hinge was measured using Hounsfield units on 30 computed tomography scans and reconstructed as a 3-dimensional mapping model. The transitional zone with low bone density was regarded as the safe hinge position with an increased capacity for bone deformation.

RESULTS

The upper and lower margins of the femoral attachment of the gastrocnemius lateral head were 9.1 ± 0.9 mm above and 8.0 ± 1.4 mm below the upper border of the lateral femoral condyle, respectively, and the femoral attachment of the gastrocnemius lateral head was widest in the anteroposterior dimension 0.4 ± 1.7 mm above the upper border of the lateral femoral condyle. The incidence of unstable lateral hinge fractures during osteotomy was significantly decreased in group 1 compared with group 2 (group 1: 0/10; group 2: 5/10; P = .01). An isolated transitional zone with low bone density was observed in all 30 knees and located 1.3 ± 0.8 mm above the upper border of the lateral femoral condyle. Bone density of the transitional zone with low bone density was significantly lower than surrounding femoral cortices (P < .001).

CONCLUSION

Only the upper border of the lateral femoral condyle can be recommended as an ideal hinge position to prevent unstable lateral hinge fractures during biplanar medial closing wedge distal femoral osteotomy based on soft tissue coverage and bone density.

CLINICAL RELEVANCE

When the hinge is positioned at the upper border of the lateral femoral condyle during biplanar medial closing wedge distal femoral osteotomy, the risk of unstable hinge fractures can be minimized.