Optimizing the use of local muscle flaps for knee megaprosthesis coverage

Coverage of lateral soft tissue defects with sartorius muscle flap after distal femoral replacement for malignant bone tumors

INTRODUCTION

To prevent infection after limb-sparing surgery for primary malignant bone tumors, it is important to cover the megaprosthesis with muscle tissue that has sufficient blood flow. Coverage with a lateral gastrocnemius flap has been reported in cases of distal femoral replacement in which the vastus lateralis and vastus intermedius muscles have been resected; however, the risk of peroneal nerve palsy is reportedly high because the muscle flap passes near the peroneal head. This study was performed to examine the postoperative outcomes of patients with primary malignant bone tumors of the distal femur who underwent wide resection (including the vastus lateralis and vastus intermedius muscles) followed by reconstruction with a megaprosthesis and coverage of the lateral side of the prosthesis with a sartorius muscle flap.

METHODS

We retrospectively analyzed three patients who underwent reconstruction with a megaprosthesis after wide resection of a primary malignant bone tumor of the distal femur involving the vastus lateralis and vastus intermedius muscles and reconstruction of the soft tissue defect on the lateral side of the prosthesis with a sartorius muscle flap.

RESULTS

The average defect size was 6 × 13 cm, the average time required for a sartorius muscle flap was 100 min, and the average implant coverage was 93%. The average postoperative follow-up period was 35 months, during which no postoperative complications such as infection, skin necrosis, or nerve palsy occurred.

DISCUSSION

The distally based sartorius muscle flap is easy to elevate in the supine position, has minimal functional loss after harvesting, and has minimal risk of nerve palsy. It can be advocated as the first option for coverage of soft tissue defects lateral to distal femoral replacement.

Anatomic feasibility study of a sartorius myocutaneous flap with a distally based pedicle and proximal skin paddle

INTRODUCTION

We conducted an anatomic feasibility study of a sartorius myocutaneous flap with a distally based pedicle and proximal skin paddle to cover soft tissue defects of the knee region.

HYPOTHESIS

A recent anatomic study by Mojalla showed that the sartorius muscle had 2 distinct pedicles, making it possible to isolate this muscle on its distal pedicle and harvest it with a skin paddle.

MATERIALS AND METHODS

This anatomic study was conducted on 10 lower limbs. The 2 criteria assessed were (1) the viability of our proximal skin paddle and (2) the arc of rotation and coverage obtained with this myocutaneous flap.

RESULTS

We identified 7 proximal skin paddles after the injection of India ink into the distal pedicle of the sartorius muscle. In all cases, the arc of rotation of the flap allowed coverage of the knee region. The mean distance between the inferior edge of the skin paddle and the proximal border of the patella (DBAP) was measured at 13cm, and the mean distance between the superior edge of the flap paddle and the anterior superior iliac spine (DASIS) at 16cm. The average skin paddle size was 14 by 7cm.

DISCUSSION

Our anatomic study demonstrated the feasibility of our sartorius flap with a distally based pedicle and proximal skin paddle. This technique may be a viable alternative when using gastrocnemius flaps is not feasible, or the surgeon lacks the microsurgical skills to perform free flaps.

LEVEL OF EVIDENCE

IV; descriptive anatomic study.

Risk Factors and Management of Prosthetic Joint Infections in Megaprostheses-A Review of the Literature

Prosthetic joint infection (PJI) is the most common mode of failure of megaprostheses, yet the literature on the topic is scarce, and studies report conflicting data regarding the optimal treatment strategy. Patients with megaprostheses PJI are often immunosuppressed, and surgeons must balance the trade-off between treatment efficacy and morbidity associated with the surgery aiming for infection eradication. Our review on megaprostheses PJI focuses on two axes: (1) risk factors and preventative strategies; and (2) surgical strategies to manage this condition. Risk factors were classified as either unmodifiable or modifiable. Attempts to decrease the risk of PJI should target the latter group. Strategies to prevent PJI include the use of silver-coated implants, timely discontinuation of perioperative antibiotic prophylaxis, and adequate soft tissue coverage to diminish the amount of dead space. Regarding surgical treatment, main strategies include debridement, antibiotics, implant retention (DAIR), DAIR with modular component exchange, stem retention (DAIR plus), one-stage, and two-stage revision. Two-stage revision is the "gold standard" for PJI in conventional implants; however, its success hinges on adequate soft tissue coverage and willingness of patients to tolerate a spacer for a minimum of 6 weeks. DAIR plus and one-stage revisions may be appropriate for a select group of patients who cannot endure the morbidity of two surgeries. Moreover, whenever DAIR is considered, exchange of the modular components should be performed (DAIR plus). Due to the low volume of megaprostheses implanted, studies assessing PJI should be conducted in a multi-institutional fashion. This would allow for more meaningful comparison of groups, with sufficient statistical power. Level of evidence: IV.

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.

Pedicled vastus lateralis myocutaneous flap for sacropelvic defects after wide oncologic resection: Wound complications and outcomes

BACKGROUND AND OBJECTIVES

Adequate coverage of the soft tissue defects from wide resection of sacropelvic malignancies remains challenging. The vastus lateralis flap has been described for coverage in the setting of trauma and infection. This flap has not been described for coverage of sacropelvic tumor defects.

METHODS

This is a retrospective cohort study of adult patients who underwent wide resection of a primary sacropelvic malignancy with reconstruction employing a pedicled vastus lateralis flap at two tertiary care centers. Patient demographics, tumor staging, and rate of complications were assessed.

RESULTS

Twenty-eight patients were included, with a median age of 51 years. The most common primary tumor was chondrosarcoma followed by chondroblastic osteosarcoma. The median follow-up was 1.1 years. There were 10 cases of wound infection requiring re-operation and three cases of flap failure.

CONCLUSIONS

We describe a pedicled vastus lateralis flap for coverage of defects after wide resection of sacropelvic malignancies. A large proportion of our cohort had independent risk factors for wound complications. Even with a cohort with high baseline risk for wound complications, we show that the use of a pedicled vastus lateralis flap is a safe reconstructive option with a wound complication rate in line with the literature.

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.

Differences in Kinematic and Kinetic Patterns According to the Bone Tumor Location after Endoprosthetic Knee Replacement Following Bone Tumor Resection: A Comparative Gait Analysis between Distal Femur and Proximal Tibia

Modular endoprostheses are frequently used to reconstruct skeletal and knee defects from bone tumor resection and preserve joint function in patients with bone tumors around the knee. Depending on the tumor location, the muscles and extent of the tumor can vary, which can affect gait function. This study aimed to analyze kinetic and kinematic characteristics according to tumor location in patients with endoprosthetic knee replacements after bone tumor resection. Gait analyses were performed in 16 patients who underwent knee endoprosthesis due to tumors around the knee. We divided the patients into distal femur (n = 7) and proximal tibia (n = 9) groups and conducted between-group comparisons and comparisons with healthy participants. Compared with the control group, the distal femur group showed a tendency for knee extension, and the proximal tibia group showed increased maximal dorsiflexion during stance. The proximal tibia group maintained a flexed hip during the entire gait cycle, compared with the distal femur group. In summary, our results suggest a difference in gait between the distal femur and proximal tibia groups. Patients who have undergone knee prosthesis after knee tumor resection may require different rehabilitation strategies according to the tumor location.

Mid- to long-term results of allograft-prosthesis composite reconstruction after removal of a distal femoral malignant tumor are comparable to those of the proximal tibia

PURPOSE

To compare the outcomes of allograft-prosthesis composite for reconstruction after malignant tumors at the distal femur and proximal tibia.

METHODS

Case-control study of 24 patients with distal femur tumor and 21 with proximal tibia tumor. Union of the allograft-host interface was assessed by the International Society of Limb Salvage criteria, and complications according Henderson. Functional outcome was evaluated by the Musculoskeletal Tumor Society (MSTS) score, Western Ontario and McMaster Universities (WOMAC) score, and pain by a visual analog scale.

RESULTS

The median follow-up in the femoral group was 11.4 (range 2.3-25.0) years, and 10.1 (range 2.2-25.0) in tibial group. Incorporation of the allograft was successful in more than 90% in both groups. Tumor location was not significant predictor for allograft failure in multivariate analysis. Aseptic prosthesis loosening occurred in two patients in either group, and another patient in the tibial group had a breakage of the tibial insert. Excluding local recurrences and amputations, the prosthesis survival at 10 years was 94.1% in the femoral group, and 83.3% in the tibial group (n.s.). For the patients with preserved limb, the median MSTS score was 23.6 in the femoral group and 22.8 in tibial group (n.s.). Likewise, there were no significant differences in median WOMAC score (n.s.) or VAS pain (n.s.).

CONCLUSIONS

Allograft-prosthesis composite is an effective procedure for distal femur tumors related to the graft, prosthesis survival, and functional outcomes. The results are comparable to those for proximal tibial tumors.

LEVEL OF EVIDENCE

Therapeutic study, Level III.

Does Patellar Tendon Repair With Gastrocnemius Flap Augmentation Effectively Restore Active Extension After Proximal Tibial Sarcoma Resection?

BACKGROUND

A rotational gastrocnemius flap is often used for soft tissue reconstruction after proximal tibia sarcoma resection. However, little is known about the frequency and severity of complications and the recovery of extensor function after this procedure.

QUESTIONS/PURPOSES

After gastrocnemius flap reconstruction with split-thickness skin grafting (STSG) to augment the extensor mechanism repair after proximal tibial resection for sarcoma, we asked: (1) What ROM was achieved (including extensor lag and active flexion)? (2) How often did complications and reoperations occur and what caused them?

METHODS

Between 1991 and 2014, one surgeon treated 26 patients with proximal tibial resections for primary bone sarcoma. Of these, 18 were reconstructed with the preferred approach: resecting the proximal tibia leaving the patellar tendon in continuity with the tibialis anterior fascia whenever possible (10), cementing a stemmed proximal tibial endoprosthesis, suturing the patellar tendon to the implant, rotating a medial (16) or lateral (two) gastrocnemius flap over the tendon and prosthesis to augment the repair, and covering the flap with STSG. Alternative methods were used when this was technically impossible (one patient), when there was no advantage to secondary soft tissue coverage (two patients), or when the limb could not be salvaged (five patients). Of the 18 treated with gastrocnemius flaps, two were lost to followup or died of disease before the 24-month minimum and excluded; the median followup of the remaining 16 was 6 years (mean, 9.9 years; range, 2.3-21.7 years); three patients died of disease, and four have not been seen within the last 5 years. We reviewed medical records for passive and active extension, maximum flexion achieved, and complications requiring reoperation. ROM in patients with successful limb salvage was graded as excellent (flexion ≥ 110° and no lag), good (flexion 90°-110° and lag ≤ 10°), fair (one function limited: either flexion < 90° or lag > 10°), or poor (both functions limited: flexion < 90° and lag > 10°).

RESULTS

At latest followup, three patients had undergone amputation for deep infection. Of those remaining, median active flexion was 110° (mean, 104°; range, 60°-120°) and extensor lag was 0° (mean, 4°; range, 0°-10°). ROM was excellent in nine patients, good in three, fair in one, and poor in none. We observed 18 complications requiring reoperation in 12 patients, including deep infection (four), patellar tendon avulsion/attenuation (three), and flap necrosis (one). Survivorship free from revision or loss of the gastrocnemius flap was 74% (95% confidence interval [CI], 5.6-95.8) at 2, 5, and 10 years. Survivorship free from reoperation for any cause was 74% (95% CI, 52.0-96.0) at 2 years, 52% (95% CI, 25.8-77.8) at 5 years, and 35% (95% CI, 0-61.5) at 10 years using Kaplan-Meier analysis.

CONCLUSIONS

Although most patients regained functional ROM including active extension, 12 required reoperation for complications including infection and early extensor mechanism failures. Despite the observed risks, we believe the gastrocnemius flap with STSG should be considered a suitable approach to provide active extension and soft tissue coverage given the paucity of good surgical options for extensor mechanism reconstruction in this challenging clinical setting.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Patellar height influences knee function in patients with aggressive bone tumors of the proximal tibia after endoprosthetic reconstruction

BACKGROUND

The proximal tibia is the second most common site of aggressive bone tumors. In proximal tibia resection, the patellar tendon is sectioned one to two centimeters from its insertion on the tibial tubercle, which makes it technically challenging to achieve an appropriate patellar height and firm fixation of the patellar tendon. The purpose of this study was to determine whether the patellar height influences knee function after proximal tibia endoprosthetic reconstruction (EPR).

METHODS

Twenty-nine patients with pathologically confirmed aggressive bone tumors in the proximal tibia were retrospectively analyzed. We used the Insall-Salvati ratio (ISR) and the Blackburne-Peel index (BPI) to radiographically analyze the patellar height. Functional outcomes were retrospectively assessed using the Musculoskeletal Tumor Society (MSTS) score, the Oxford Knee Score (OKS) and the range of motion (ROM) which was evaluated through extensor lag and active flexion. Univariate analysis with Pearson's correlation and a multivariate linear regression of patient characteristics and surgery-related changes were performed.

RESULTS

The postoperative ISRs were negatively correlated with the functionality domain of the MSTS score (function, gait, walking) and the OKS. Pearson's correlation analysis showed a significant correlation between the postoperative ISR and extensor lag. The change in patellar height had no impact on the active flexion of the knee.

CONCLUSIONS

Patellar height is an independent factor contributing to knee function after proximal tibia EPR. The quality of patellar tendon reconstruction is a key point in proximal tibia EPR after tumor resection.

Survival, complications and functional outcomes of cemented megaprostheses for high-grade osteosarcoma around the knee

PURPOSE

We initiated a retrospective study on the long-term survival of cemented endoprostheses for bone tumours around the knee to answer the following questions: (1) What was the survival of these patients? (2) What was the overall survival of cemented prostheses around the knee? (3) What types of failures were observed in these reconstructions? (4) Did the survival and complications vary according to the site of the implant? (5) What was the functional result after cemented prosthesis replacement around the knee?

METHODS

From January 2006 to December 2013, 108 consecutive patients with an average age of 25 years, who had mature bone development as evidenced by imaging examinations, underwent 108 cemented endoprosthetic knee replacements for osteosarcoma resection. All patients received neoadjuvant chemotherapy using a multi-drug protocol consisting of high dose methotrexate (HDMTX), doxorubicin (ADM), cisplatin (DDP) and high dose ifosfamide (HDIFO). When extensor mechanism reconstruction was required, we ran nonabsorbable sutures through designated holes in the tibial component to fix detached hamstrings and the remaining ligaments in an imbricated fashion as well as reinforced the reconstruction with a medial gastrocnemius flap. Seventy-two (72/108, 66.7%) lesions were located in the distal femur and 36 (36/108, 33.3%) lesions at the proximal tibias. Nineteen patients were staged as IIA and 89 as IIB according to the Enneking staging system. The average follow-up was 53.3 months (range 12-125 months), with a minimum oncological follow-up of one year. Survival, prosthetic failure, complications and functional outcomes were recorded and reassessed at every visit after the primary operation.

RESULTS

At the final follow-up, the oncologic results showed that 33 patients died from metastases, and local recurrence occurred in ten patients. The estimated overall five-year and eight-year survival rates were 71% (95% CI: 62.4-79.65%) and 67.2% (95% CI: 58-76.4%), respectively. In this study, a total of 51 complications occurred in 45 patients, and at the end of follow-up, 59 patients had prostheses in situ. The estimated overall five-year and eight-year implant survival rates were 77.7% (95% CI: 67.9-87.5%) and 54.5% (95% CI: 31.4-77.6%), respectively, when patients who died with their original prostheses were censored. In total, 21 (21/108, 19.4%) implants failed, five due to infections (5/21), eight due to aseptic loosening (8/21), four due to local recurrence (4/21), three due to structural failure (3/21) and one due to soft tissue failure (1/21). The average Musculoskeletal Tumor Society Score (MSTS) at the most recent follow-up was 22.9 (9-30) points on a 30-point scale, which indicated an excellent or good functional outcome. Analysis of the results based on implant site revealed a slight difference of the estimated five-year prosthesis survival between implants located in the distal femur and those located in the proximal tibia [86.1% (95% CI: 75.5-97%) versus 66.9% (95% CI: 49.8-83.9%); P = 0.09]. However, the functional outcomes and complication rates of prostheses located in the distal femur were both better than those located in the proximal tibia.

CONCLUSIONS

With effective management strategies for complications, cemented endoprosthetic reconstruction of the proximal tibia and distal femur using an extensor mechanism reconstruction technique provides a reliable method of reconstruction following tumour resection around the knee. Level of Evidence Level IV, therapeutic study.

Megaprosthesis versus Allograft Prosthesis Composite for massive skeletal defects

Massive skeletal defects are encountered in the setting of tumors necessitating excision, failed total hip arthroplasty with periprosthetic bone loss, periprosthetic fracture, complex trauma, multiple failed osteosynthesis and infection. Reconstruction of the segmental defects poses a tremendous challenge to the orthopaedic surgeons. The goal of osseous reconstruction of these defects is to restore the bone length and function. Currently the most commonly employed methods for reconstruction are either a megaprosthesis or an Allograft Prosthesis Composite (APC). Megaprosthesis, initially created for the treatment in neoplastic pathologies are being used for the non-neoplastic pathologies as well. The longevity of these implants is an issue as majority of the patients receiving them are the survivors of oncologic issue or elderly population, both in which the life expectancy is limited. However, the early complications like instability, infection, prosthetic breakage and fixation failure have been extensively reported in several literatures. Moreover, the megaprostheses are non-biological options preventing secure fixation of the soft tissue around the implant. The Allograft Prosthesis Composites were introduced to overcome the complications of megaprosthesis. APC is made of a revision-type prosthesis cemented into the skeletal allograft to which the remaining soft tissue sleeve can be biologically fixed. APCs are preferred in young and low risk patients. Though the incidence of instability is relatively low with the composites as compared to the megaprosthesis, apart from infection, the newer complications pertaining to APCs are inevitable that includes non-union, allograft resorption, periprosthetic fracture and potential risk of disease transmission. The current review aims to give an overview on the treatment outcomes, complications and survival of both the megaprostheses and APCs at different anatomic sites in both the upper and lower limbs.

Pedicled Rotational Medial and Lateral Gastrocnemius Flaps: Surgical Technique

Gastrocnemius flaps have been used for decades to reconstruct defects of the proximal tibia and knee. They have proven to be useful in the soft-tissue reconstruction of defects caused by trauma, tumors, and infections about the knee, and the reconstruction of extensor mechanism discontinuity with and without total joint arthroplasty. The flaps have low failure rates and a distinct proximally based blood supply that allows them to be elevated and rotated up to 15 cm above the level of the knee joint. The vascular anatomy is reproducible because rotational flaps do not require microvascular anastomosis. An understanding of the applied surgical anatomy, approaches, and utility of the gastrocnemius flap makes the technique a useful tool for the orthopaedic surgeon when plastic surgery assistance is not readily available.

Extensor reconstruction of the knee using the fibular transposition technique after proximal tibial resection

BACKGROUND

Reconstruction of the extensor mechanism after resection of the proximal tibia is challenging, and several surgical procedures are available. The purpose of this study was to determine the outcome of the fibular transposition technique for reconstruction of the extensor mechanism of the knee after proximal tibial resection.

METHODS

We retrospectively reviewed five consecutive patients who underwent resection of the proximal tibia with prosthetic reconstruction and reconstruction of the extensor using fibular transposition between 1997 and 2011. There were two female and three male patients with a mean age of 50years (range, 27 to 76years). A follow-up evaluation included both passive and active range of motion, extensor lag, the MSTS score and complications.

RESULTS

Patients were followed up for 93months (range, 44 to 160months). The mean extensor lag and active flexion were four degrees (range, 0 to 10°) and 103° (range, 85 to 110°), respectively. The mean MSTS score was 80% (range, 73 to 90%). All patients were able to ambulate without crutches at the latest follow-up.

CONCLUSIONS

The utilization of the fibular transposition technique is a simple, reliable, and successful procedure for extensor reconstruction after proximal tibial resection.

Systematic Review and Comparative Meta-Analysis of Outcomes Following Pedicled Muscle versus Fasciocutaneous Flap Coverage for Complex Periprosthetic Wounds in Patients with Total Knee Arthroplasty

Background

In cases of total knee arthroplasty (TKA) threatened by potential hardware exposure, flap-based reconstruction is indicated to provide durable coverage. Historically, muscle flaps were favored as they provide vascular tissue to an infected wound bed. However, data comparing the performance of muscle versus fasciocutaneous flaps are limited and reflect a lack of consensus regarding the optimal management of these wounds. The aim of this study was to compare the outcomes of muscle versus fasciocutaneous flaps following the salvage of compromised TKA.

Methods

A systematic search and meta-analysis were performed to identify patients with TKA who underwent either pedicled muscle or fasciocutaneous flap coverage of periprosthetic knee defects. Studies evaluating implant/limb salvage rates, ambulatory function, complications, and donor-site morbidity were included in the comparative analysis.

Results

A total of 18 articles, corresponding to 172 flaps (119 muscle flaps and 53 fasciocutaneous flaps) were reviewed. Rates of implant salvage (88.8% vs. 90.1%, P=0.05) and limb salvage (89.8% vs. 100%, P=0.14) were comparable in each cohort. While overall complication rates were similar (47.3% vs. 44%, P=0.78), the rates of persistent infection (16.4% vs. 0%, P=0.14) and recurrent infection (9.1% vs. 4%, P=0.94) tended to be higher in the muscle flap cohort. Notably, functional outcomes and ambulation rates were sparingly reported.

Conclusions

Rates of limb and prosthetic salvage were comparable following muscle or fasciocutaneous flap coverage of compromised TKA. The functional morbidity associated with muscle flap harvest, however, may support the use of fasciocutaneous flaps for coverage of these defects, particularly in young patients and/or high-performance athletes.

Lateral gastrocnemius myocutaneous flap transposition to the midlateral femur: extending the arc of rotation

We report the successful use of an extended lateral gastrocnemius myocutaneous flap for coverage of the midlateral femur using successive delayed elevations. A 62-year-old man underwent wide resection of a liposarcoma of the right anterior thigh with free flap reconstruction and subsequent radiation therapy 10 years before. Four years later, the patient fractured his irradiated femur and was treated with a retrograde intramedullary nail, which subsequently became infected, causing osteomyelitis of the distal femur, septic arthritis of the knee joint, and nonunion of his pathologic fracture. Although advised by numerous surgeons to undergo above-knee amputation, we offered our motivated patient a multidisciplinary approach to clear his infection and pathology; implanted new orthopedic hardware; performed delayed flap reconstruction; and rehabilitated him back to painless, unassisted ambulation. The extended lateral gastrocnemius myocutaneous flap used provided perfused soft tissues and durable coverage for the patient's exposed orthopedic hardware of the midlateral femur, 14 cm above the joint line of the knee. By using this flap to cover a femur defect well above published heights, our patient avoided amputation after years of worsening incapacitation.

Treatment solutions are unclear for perimegaprosthetic infections

BACKGROUND

Infection about a megaprosthesis is a dreaded complication. Treatment options vary from débridement alone to staged revisions, arthrodesis, and amputation. Indications for how to treat this complication are unclear.

QUESTIONS/PURPOSES

We therefore determined (1) the incidence of perimegaprosthetic infections, (2) the methods of treatment, (3) the number of patients who failed their original treatment plan, and (4) the characteristics of the infection.

METHODS

We retrospectively identified 291 patients who had megaprostheses implanted between 2001 and 2011 and identified all those surgically treated for a perimegaprosthetic infection during that time. We defined a treatment failure as any unplanned reoperation or death due to uncontrolled infection. All patients with failure had a minimum followup of 1 year (mean, 3.3 years; range, 1-8 years).

RESULTS

Of the 291 patients, 31 (11%) had subsequent infections. Surgical management varied among irrigation and débridement (n=15), single-stage revisions (n=11), two-stage revisions (n=4), and amputations (n=1). Sixteen patients failed their original treatment plan: 13 required additional surgery and three died. Infections were mostly chronic and single organism with five being methicillin-resistant Staphylococcus aureus.

CONCLUSIONS

An 11% incidence of perimegaprosthetic infections is consistent with the increased risk of infection seen in other studies. A variety of surgical methods were employed at our institution and by those contributing to the literature without clear evidence of superiority of one method over another. Given the complicated medical and surgical histories of these patients, individualization in decision making is necessary.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Extensor function after medial gastrocnemius flap reconstruction of the proximal tibia

BACKGROUND

Reconstruction of the extensor mechanism after resection of the proximal tibia is challenging, and several methods are available. A medial gastrocnemius flap commonly is used, although it may be associated with an extensor lag. This problem also is encountered, although perhaps to a lesser extent, with other techniques for reconstruction of the extensor apparatus. It is not known how such lag develops with time and how it correlates with functional outcome.

QUESTIONS/PURPOSES

We therefore (1) assessed patellar height with time, (2) correlated patellar height with function using the Musculoskeletal Tumor Society (MSTS) score, and (3) correlated patellar height with range of motion (ROM) after medial gastrocnemius flap reconstruction.

METHODS

Sixteen patients underwent tumor endoprosthesis implantation and extensor apparatus reconstruction between 1997 and 2009 using a medial gastrocnemius flap after sarcoma resection of the proximal tibia. These patients represented 100% of the population for whom we performed extensor mechanism reconstructions during that time. The minimum followup was 2 years (mean, 5 years; range, 2-11 years). Fourteen patients were alive at the time of this study. We used the Blackburne-Peel Index to follow patellar height radiographically with time. Functional outcomes were assessed retrospectively using the MSTS, and ROM was evaluated through active extensor lag and flexion.

RESULTS

Eleven patients had patella alta develop, whereby the maximal patellar height was reached after a mean of 2 years and then stabilized. More normal patellar height was associated with better functional scores, a smaller extensor lag, but less flexion; the mean extensor lag (and flexion) of patients with patella alta was 17° (and 94°) compared with only 4° (and 77°) without.

CONCLUSIONS

In our patients patella alta evolved during the first 2 postoperative years. Patella alta is associated with extensor lag, greater flexion, and worse MSTS scores. Surgical fixation of the patellar tendon more distally to its anatomic position or strict postoperative bracing may be advisable.

LEVEL OF EVIDENCE

Level IV, clinical cohort study. See the Guidelines for Authors for a complete description of levels of evidence.

Soft-tissue optimization of limb salvage with knee endoprosthesis: the 10-year experience at the Children's Hospital of Philadelphia

PURPOSE

Limb salvage in bone sarcomas requires resection and joint and soft-tissue reconstruction. Suboptimal coverage can lead to prosthesis infection, subsequent hardware exposure, or loss with eventual amputation. In the pediatric sarcoma population, it is essential to not only have viable soft-tissue coverage but one that minimizes donor site morbidity and maximizes function and growth over time.

METHODS

This is a retrospective review of all sarcoma patients with primary gastrocnemius and soleus muscle flap coverage of modular knee endoprosthesis over the 10-year period between 1997 and 2007. All patients had resection of the skin at the tibial biopsy site prior to their primary tumor resection surgery. After resection of the knee joint and proximal tibia with clear margins, the bony defect was reconstructed with an endoprosthesis. The gastrocnemius and soleus muscles were then independently rotated to cover the prosthesis and the patellar tendon.

RESULTS

Eleven patients (10 male, 1 female) with an average age of 13 years (range, 10-17) underwent resection of proximal tibia. Pathology included osteosarcoma in 9 patients, Ewing in 1, and spindle cell sarcoma in 1 patient. All patients had endoprosthetic coverage by gastrocnemius and soleus flaps; 4 patients had additional split-thickness skin graft over the gastrocnemius. The average level of tibial resection was 16.5 cm distal to the articular surface of the proximal tibia. Mean soft-tissue mass volume resected with bone was 157 cm. There was one flap failure that was reconstructed with a rectus abdominis free flap. Average follow-up was 32 months (range, 8-92 months). Two patients succumbed to metastatic disease. In this series, there was no limb loss or hardware exposure or infection. All patients achieved independent ambulation. Functionally, patients were evaluated based on the Musculoskeletal Tumor Society scale. The average score was 29 (out of a perfect score of 30). Two patients had transient foot drop that resolved with ankle foot orthosis use. Anticipated leg length discrepancy was detected in 3 patients who underwent opposite limb epiphysiodesis with ultimate limb equalization.

CONCLUSION

Soft-tissue reconstruction with gastrocnemius and soleus muscle flap coverage decreases wound complications and hardware exposure while maintaining function in the pediatric population.

Proximal tibial resections and reconstructions: clinical outcome of 225 patients

BACKGROUND

Previous studies reported variable outcome of proximal tibial resections and reconstructions. Therefore, we evaluated the survival, Musculoskeletal Tumor Society (MSTS) function, and complications of patients and reconstructions in this location.

MATERIALS AND METHODS

We reviewed the files of 225 patients with proximal tibial tumors treated with proximal tibial resection, fixed or rotating hinge megaprosthetic reconstruction and extensor mechanism reattachment using sutures, mechanical clamping, artificial ligaments, and/or gastrocnemius flap from 1985 to 2010 (mean follow-up, 90 months; median, 56; range, 2-294). Survival of patients and reconstructions, type of hinge, extensor mechanism reconstruction, MSTS function, and complications were analyzed.

RESULTS

Survival of patients with sarcomas was 68% and 62% at 5 and 10 years. Survival of megaprosthetic reconstructions was 82% and 78% at 5 and 10 years, without any difference between fixed and rotating hinge megaprostheses. MSTS function was significantly better in univariate and multivariate analysis for rotating compared to fixed hinge megaprostheses, without any difference between the types of extensor mechanism reconstructions. Most common complications were infection (12%), aseptic loosening (6%), and extensor mechanism rupture (3%).

CONCLUSIONS

Rotating hinge proximal tibia megaprosthetic reconstructions have better function compared to fixed hinge, regardless of the type of extensor mechanism reconstruction.

Reconstruction of the extensor mechanism after major knee resection

In periarticular knee resections, the relative lack of soft tissue coverage and need to reattach the extensor mechanism after en bloc resection of the tibial tuberosity with the tumor specimen complicate reconstructions and decrease postoperative function and stability of the knee joint. Distal femoral reconstructions are less problematic; muscular attachments are relatively few, neurovascular structures are not immediately adjacent to bone, and the knee extensor mechanism is usually not compromised from bone tumors. In the proximal tibia, the close proximity of the neurovascular structures in the popliteal fossa and peroneal nerve at the lateral aspect of the leg make reconstruction more difficult. Poor function is mostly related to unreliable options for knee extensor mechanism reattachment and poor soft tissue coverage. Successful and reliable attachment of the soft tissues has been a significant advance that improved functional outcomes.This article describes techniques for the reconstruction of the extensor mechanism of the knee after proximal tibia resections. Combined reconstruction techniques using direct reattachment of the patellar tendon with synthetic materials to megaprosthetic or allograft reconstructions for immediate stability, augmentation with autologous bone graft or substitutes at the attachment site, and coverage with the medial gastrocnemius muscle flap and supplementary flaps for long-term stability of the reattachment are currently considered the gold standard.

Soft-tissue management with immediate free flap transfer in segmental prosthetic replacement of proximal tibia sarcomas

Knee reconstruction with endoprosthesis after tumor resection is accepted as superior when compared with the other methods. But sometimes soft tissue reconstruction would be a challenging problem in this way of treatment. Five patients who were operated for tumor resection in this location, followed by reconstruction were presented with their one-year post operative results. Four latissimus dorsi and one rectus abdominis myocutaneous free flaps were used in these patients in order to manage soft tissue problems. All patients underwent chemotherapy in postoperative period. All flaps were successful in one year post operative examination. In this report we would like to stress the importance of surgical planning and soft tissue reconstruction of a specific patient population. We think that large musculocutaneous flaps such as latissimus dorsi and rectus abdominis musculocutaneous flaps should be preferred in soft tissue reconstruction of knee region after tumor resection followed by prosthetic replacement. Additionally, this way of treatment is superior when compared to the other methods in order to prevent complications such as prosthesis exposure or infection.

Surgical difficulties encountered with use of modular endoprosthesis for limb preserving salvage of failed allograft reconstruction after malignant tumor resection

We reviewed outcomes and discussed surgical difficulties encountered in 10 patients who had modular endoprosthesis for limb preserving salvage of failed allograft reconstruction after malignant tumor resection. Mean allograft survival time before failure was 127.4 months (range, 14-264 months). Mean length of follow-up since endoprosthesis revision surgery was 62.8 months (range, 16-132 months). There was one endoprosthesis failure, resulting in a mean endoprosthesis survival time of 56.9 months (range, 16-132). Complications included arterial laceration, nerve injury, periprosthetic crack fracture, aseptic loosening, and infection. Modular endoprosthesis remain a viable option that should be considered in any limb preserving salvage of failed allograft reconstructions. However, altered anatomy, poor/short remnant host bone, periprosthetic fractures, inadequate soft tissue coverage and infection remain important difficulties encountered.

Knee Region Coverage with Reversed Gracilis Pedicle Flap (GReSP Flap)

Introduction

To treat severe soft-tissue complications of total knee arthroplasty, we used an extended reversed gracilis flap based on secondary pedicles (the GReSP flap).

Step 1 Prepare Wound Bed

Locate the gracilis and pedicles, then debride the wound bed.

Step 2 Expose Gracilis Muscle

Expose the superficial aspect of the muscle, while protecting the saphenous vein and nerve.

Step 3 Check Muscle Perfusion

Temporarily clamp the main vascular pedicle to ensure blood supply when perfused only by the secondary pedicles.

Step 4 Mobilize Muscle Flap

Transect the proximal tendon of the gracilis muscle to provide maximal length for the muscle flap and ligate the main vascular and nerve pedicles.

Step 5 Cover with Skin Graft

Suture the flap in place and cover with skin graft.

Step 6 Postoperative Care

Immobilize the knee for two weeks; follow with rehabilitation to restore range of motion.

Results & Preop/Postop Images

We treated three patients who had an infection at the site of a total knee arthroplasty and exposure of the implant.

What to Watch For

IndicationsContraindicationsPitfalls & Challenges.

Reversed gracilis pedicle flap for coverage of a total knee prosthesis

BACKGROUND

Poor wound-healing and skin necrosis are potentially devastating complications after total knee arthroplasty. Primary soft-tissue coverage with a medial or lateral gastrocnemius transposition flap is typically the first choice for reconstruction. The aim of this study was to evaluate the use of a distally based secondary-pedicle flap of the gracilis muscle for reconstruction of a soft-tissue defect.

METHODS

The characteristics of the distally based (secondary) pedicles of the gracilis muscle were studied with use of dissection (ten cadavers) and computed tomographic angiograms (fifty patients). On the basis of the anatomical features, an extended reversed gracilis flap based on the secondary pedicles was used in three patients with severe soft-tissue complications of total knee arthroplasty.

RESULTS

The mean number of secondary pedicles was 1.8 (range, one to four). The pedicles originated from the superficial femoral or popliteal artery. The most proximal pedicle was often the largest (mean caliber, 2.0 mm), and its point of entry into the gracilis muscle was an average (and standard deviation) of 21 +/- 3.6 cm (range, 16 to 28 cm) from the ischiopubic branch. A significant positive association (p = 0.001; r(2) = 0.49) was found between the caliber of the proximal secondary pedicle and the number of other secondary pedicles. In all three patients, the adequate caliber of the secondary pedicles (as shown on preoperative computed tomographic angiograms) and good muscle vascularization confirmed the utility of the gracilis as a distally based pedicle flap.

CONCLUSIONS

For the treatment of large soft-tissue defects of the patella or the proximal part of the knee, or for soft-tissue reconstruction over an exposed total knee prosthesis, the reversed gracilis pedicle flap may be an alternative to, or may be integrated with, a lateral or medial gastrocnemius flap.