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Hindquarter amputation with pedicled fillet flap for clear cell chondrosarcoma of the proximal femur

    Overview

    Learn the Hindquarter amputation with pedicled fillet flap for clear cell chondrosarcoma of the proximal femur surgical technique with step by step instructions on OrthOracle. Our e-learning platform contains high resolution images and a certified CME of the Hindquarter amputation with pedicled fillet flap for clear cell chondrosarcoma of the proximal femur surgical procedure.
    Pelvic resections remain the most challenging of procedures for patients and surgeons alike. Regrettably there are occasions when a tumour cannot be excised without sacrificing the limb, necessitating a hindquarter amputation.
    When tumours arise in the limbs, oncology surgeons need to consider the contamination of each individual compartment when planning the surgical strategy. Where a tumour has undergone inadvertent surgery, contamination of many compartments can occur and significantly impact upon the potential to salvage a limb. At the hip, if multiple compartments and the hip joint are contaminated by tumour, then only a hindquarter amputation or rotationplasty (where a femoral tumour is excised and the ankle rotated to become and functional ‘knee’ joint) offer a curative option for a chemo-radiotherapy insensitive tumour such as clear cell chondrosarcoma. In principle, limb-salvage may still be possible in chemo-radiosensitive tumours such as Ewing’s sarcoma or in some oligometastatic bone tumours.
    The British Orthopaedic Oncology Society have produced helpful guidelines to minimise the chance of inadvertently operating on tumour cases, with the attendant risks including compromising the possibility of limb salvage surgery. The key point is that prodromal pain and injury mechanisms not in keeping with traumatic fractures are indicative of pathological fractures i.e. due to an underlying cause such as malignancy (or osteoporosis, infection, metabolic disease, dysplasia, Paget’s disease etc). In such cases there is no rush to stabilise fractures (STOP), patients should be investigated throughly including whole-body staging (SCAN) and discussed with their treating oncologist if metastatic or with a specialist orthopaedic oncologist if solitary (PLAN).
    OrthOracle readers will also find the following operative techniques of interest:
    Computer navigated P1 hemipelvectomy for chondrosarcoma and GRAFTJACKET (Wright Medical) reconstruction
    Computer navigated Hemi-pelvectomy for Ewings sarcoma
    Hindquarter amputation (for pelvic soft tissue sarcoma)

    Indications

    INDICATIONS
    The indications for hindquarter amputation are either for curative resection of malignant tumours of bone or soft-tissue where limb-salvage surgery would compromise oncological outcomes, or (rarely) for palliation in the presence of metastatic disease to improve pain and quality of life. More recently, hindquarter amputation has been used as treatment for failed limb-salvage surgery, particularly pelvic reconstruction, in the presence of infection.
    A variety of flaps have been described, depending on the residual blood supply after resection and where the tumour was located. The most common is the posterior flap based on gluteus maximus supplied by the superior gluteal pedicle. An alternative is an anterior thigh flap based on the femoral vessels. Rarely an adductor flap based on the obturator vessels is required where the superior gluteal pedicle and femoral vessels are involved by the tumour. Even more rarely the wound is closed using a ‘fillet flap’ utilising the redundant calf tissue which can be pedicled (as in this case) or a ‘free’ flap transfer requiring vascular anastomosis.
    SYMPTOMS & EXAMINATION
    A common early symptom is pain which often follows an insidious, intractable course from functional pain, to rest pain and finally night pain. Due to the rarity of the diagnosis, patients are often falsely reassured or under investigated, at least at the initial stages of the disease. Due to the distensibility of the pelvic cavity, tumours can reach a large size before a mass becomes palpable. The presence of a mass often stimulates further investigation. Patients rarely present with systemic symptoms of fevers, night sweats or weight loss except in advanced disease. Examination findings in patients with pelvic tumours are often non-specific. Acetabular involvement will often result in a limp and an irritable range of movements. Abdominal examination often demonstrates a mass in close association with the pelvis. The mass is often firm, irregular and heterogenous in texture, and fixed to underlying structures. Examination of the local lymph node structures occasionally reveals lymphadenopathy though this a rare feature. A full neurological examination should be completed as tumours will often compress neurological structures, or invade directly into the sacrum. The lower limb vascularity, both venous and arterial should be assessed looking in particular for the presence of vascular insufficiency or venous engorgement suggestive of pelvic vessels compression.
    IMAGING
    Local staging: Radiographs should form the first line investigation for any suspected bone sarcoma and often these will identify areas of lysis suggestive of infiltration. Cross-sectional imaging for local staging should comprise an MRI scan, including the whole bone including the hip and knee joint, although where pelvic surgery is contemplated, the whole pelvis and sacrum will need MRI as well. Tumours will appear as an enlarged high signal mass with soft tissue extension and in the case of tumours invading bone, lysis, destruction and oedema within osseous structures.
    Full distal staging should be completed before discussing management. In the case of soft-tissue sarcomas, this should comprise CT of the chest. Whole body bone scintigraphy is indicated in most primary bone tumours to distally stage the rest of the skeleton. Whole body imaging is often not indicated for soft-tissue sarcomas except for certain histological variants (e.g. myxoid liposarcomas, leiomyosarcomas) in which whole body MRI or whole body PET-CT imaging is required. Increasingly whole body MRI is used to stage Ewing’s sarcomas of bone.
    ALTERNATIVE OPERATIVE TREATMENT
    Limb-salvage is always the primary aim of surgical treatment at the outset. The principles of surgical management should be to remove the tumour in its entirety, with a clear margin with a degree of function post-operation that is acceptable to the patient. Where this is not achievable with limb-salvage, an amputation should be considered. In the case of pelvic sarcoma surgery the indications for hindquarter amputation are involvement of two of the following: the hip joint, sciatic nerve or femoral vessels. This may be offered after the administration of neo-adjuvant radiotherapy which would be aimed at arresting tumour growth, reducing the risk of local recurrence, or rarely to downstage disease and allow limb-salvage surgery. In advanced disease, hindquarter amputation may occasionally be offered to palliate particularly in the presence of intractable pain and/or tumour fungation.
    NON-OPERATIVE MANAGEMENT
    Non-operative management may be considered in the presence of advanced metastatic disease, or where hindquarter amputation is not acceptable for the patient. In such cases, the patient may receive radiotherapy with palliative intent.
    CONTRAINDICATIONS
    Contraindications to hindquarter amputation are patient related, where the procedure is unacceptable to the patient or where the risk of peri-operative mortality is deemed too high to undertake the procedure. Relative contraindications now include patients in whom only palliative pain relief is achievable as recent literature has highlighted that 1 in 3 palliative hindquarter patients die within 30 days of surgery (Kiiski et al. Surgical and oncological outcomes after hindquarter amputation for pelvic sarcoma. Bone Joint J 2020;102-B:6, 788-794).

    Setup

    Patients are positioned in a sloppy lateral position to allow access to the midline anteriorly and posteriorly. After general anaesthesia, both spinal and epidural anaesthesia combined with adrenaline infusion is commenced for hypotensive anaesthesia, proven to reduce blood loss and transfusion requirements (Freeman et al. Hypotensive Epidural Anesthesia Reduces Blood Loss in Pelvic and Sacral Bone Tumor Resections. Clin Orthop Relat Res. 2017 Mar;475(3): 634–640). Bowel preparation is given pre-operatively to cleanse the colon, urinary catheters decompress the bladder for safety and central venous and arterial monitoring is inserted.
    After intravenous antibiotics (vancomycin and meropenem) and tranexamic acid, mechanical thromboprohylaxis pumps on the contralateral calf and forced air warming are applied. The patient is positioned in an ultra-clean air flow theatre.

    Operation – 1

    This AP right hip radiograph was taken at presentation of this 33 year old patient to the Emergency department and shows a displaced intracapsular fracture with no history of trauma but a three month history of prodromal pain.

    Six weeks after fracture stabilisation surgery was performed, the fracture had not healed and the screws were backing out as the fracture displaces back into varus.

    Six months after surgery there is a non-union with limb shortening and evidence of avascular necrosis.

    Due to ongoing symptoms of pain attributed to failed stabilisation and suspected avascular necrosis the patient was listed for removal of screws and conversion to a total hip replacement. Upon removal of the screws, it was appreciated that there was an underlying bone tumour and surgery ceased. The patient was then referred to a specialist bone tumour centre.

    T2-weighted coronal MRI sequence highlighting tumour involvement of the femoral head, trochanter extending into the diaphysis. It is also possible to see the site of previous (SI) skin incisions, which are potentially contaminated along with all of the anterior, lateral and posterior anatomical structures around the proximal femur.

    Axial T2-weighted MRI highlighting the (S) surgical incision laterally leading to the fascia lata and trochanter, the high signal ares denoting the (CCC) clear cell chondrosarcoma in the proximal femur and the position of the screws in the (FH) femoral head.

    Axial T1-weighted MRI again showing the surgical incision, the now low signal tumour in the bone and the screw position in the femoral head. We can also appreciated the (FV) femoral vessels medial to the femoral nerve, and the wasting of the (GMax) gluteus maximus, (TFL) tensor fascia lata and (RF) rectus femoris compared to the contralateral side.

    Staging CT chest was clear, indicating that there was no evidence of metastasis and that a wide resection of the tumour would be potentially curative.

    The previous lateral hip incision for the two previous inadvertent operations is clear, centred over the greater trochanter and proximal thigh. Marked with indelible ink is the proposed skin incision for this procedure shown arising from the anterior superior iliac spine (ASIS), continuing over the iliac crest and over the (PSIS) posterior iliac spine towards the buttock. The (IT) ischial tuberosity is also marked as a reference point for bony anatomical landmarks.

    After alcoholic chlorhexidine skin preparation has been applied twice, the entire limb is isolated and the skin is covered using Ioban incision drapes as shown. The contralateral leg has pneumatic stockings applied to mechanically apply intermittent compression to the calf throughout the operation. The chest is covered with a forced air warming blanket to prevent hypothermia throughout the procedure. This operation is performed within an ultra-clean air flow theatre.

    The anterior skin incision extends from the iliac crest over the anterior superior iliac spine (ASIS) down along the groin crease as can be seen. The groin incision follows the crease between the perineum and thigh, about 3 cms away from the anal margin and following the crease of the buttock posteriorly.

    The skin incision is started over the iliac crest continuing over the anterior superior iliac spine (ASIS) and down along the marked incision along the inguinal ligament.The anatomical landmarks for the inguinal ligament are the ASIS and the pubic tubercle (PT). The incision is deepened through the skin and fat down to the abdominal wall.

    Having gone through the fat layer, the deep fascia covering the abdominal wall muscles inserting onto the iliac crest should be identified.The superficial fascia overlying the anterior superior iliac spine (ASIS) is marked in the centre of the photograph and this identifies the landmark for the beginning of the inguinal ligament. Careful haemostasis at this stage is required. There are no structures at risk during this step.


    Using cautery divide the abdominal wall muscles as they are arising off the medial aspect of the iliac crest, taking care not to enter into the subiliacus plane. By dividing these muscles, we will enter the retroperitoneum. The layers of the abdominal wall after the superficial fascia are the external oblique, internal oblique and transversus abdominis muscles and the transversalis fascia deepest before the peritoneum is encountered.

    As the plane is identified, release the rest of the abdominal wall as it inserts onto the inguinal ligament.

    Progressing from anterior to posterior release the abdominal muscles off the iliac crest towards the posterior ilium and sacrum to enter the retroperitoneal space.

    As the muscles are released off the iliac crest (IC), the iliacus fascia (IF) comes into view, which overlies the inner table of the ilium and confirms one is in the retroperitoneal space.Here one starts to encounter the neurovascular structures of the external iliacs and femoral nerve. Care is now taken as we move medially, not to damage any vital structures including the peritoneum, external iliac vessels and bladder.

    Identify the external inguinal ring medially which is located just proximal to the pubic tubercle, an easily palpated anatomical landmark and the insertion of the inguinal ligament.Insert a curved artery clip into the inguinal canal and taking care not to damage its contents. Release the inguinal canal thus dividing the external and internal oblique fibres that make up the anterior wall of the inguinal canal. This will expose the contents of the inguinal canal (spermatic cord and contents/round ligament, ilioinguinal nerve, genital branch of the genitofemoral nerve). the contents of the spermatic cord are: vas deferens, testicular artery and vein, artery of the ductus deferens, cremasteric artery, pampiniform plexus, autonomic nerve and lymphatics.

    Having released the inguinal canal from external to internal ring, identify the external iliac vessels.Most of the anterior dissection is completed and we can start to get a glimpse of the (EI) external iliacs and neural structures, including the (FN) femoral nerve and the (LFCN) lateral femoral cutaneous nerve of the thigh, running over the (P) psoas and (I) iliacus muscles on the inner table on the pelvis.

    With gentle retraction, we can identify the (P) psoas muscle, which has been marked with the forceps and the (FN) femoral nerve just deep to psoas in-between psoas and the (I) iliacus muscle. The other small nerve branches seen running over psoas are the (LFCN) lateral femoral cutaneous nerve medially and the (II) ilioinguinal nerve laterally. The femoral nerve exits the pelvis at the midpoint of the inguinal ligament into the femoral triangle.

    Dissect the external iliac vessels, then sloop the external iliac vein.We start by getting control of the external iliac vessels using Debakey forceps and Lahey forceps, the (EIV) external iliac vein is dissected carefully.

    A (blue) rubber sloop is passed beneath the external iliac vein using the Lahey to grasp, so we can control the vessel if there is any bleeding. A light 3 inch clip is applied to the two ends of the sloop, taking care not to permit any obstruction to venous return.

    Identify and dissect the external iliac artery, then sloop the external iliac artery.Having slooped the vein we now get control of the (EIA) external iliac artery by repeating the previous step of dissecting around the external iliac artery using Lahey’s forceps.

    We now pass a red sloop, again using the Lahey’s forceps around the external iliac artery for control, should there be any bleeding. Another artery clip is applied to the sloop ends for security.

    Having controlled the external iliacs, we now dissect out the psoas muscle, which needs to be divided to give us improved access to the vessels and a finger is passed from medial to lateral around the psoas muscle taking care not to pick up any neuromuscular structures, prior to division with cautery. Alternatively a swab may be passed beneath the muscle belly to cauterise onto.

    Operation – 2

    Using cautery divide the psoas muscle. Using cautery and using the surgeon’s finger to lift psoas out of the wound, so as to avoid inadvertent injury to other structures (femoral nerve, external and internal iliac vessels), divide the psoas muscle.

    Having divided psoas, the (FN) femoral nerve can now be visualised, which passes between psoas and the (I) iliacus muscle that is just deep and lateral to it.

    With gentle retraction on the abdominal wall here seen is the (I) iliacus muscle, the (FN) femoral nerve and the cut edge of the (P) psoas and now we have a better view of the (EIV) external iliac vein.

    Having divided psoas access is improved, trace the external iliac proximally to find the common iliac vein and using Debakey forceps and a Lahey carefully pass a blue rubber sloop around the common iliac vein, to get control in case of any bleeding.Care is taken not to inadvertently damage any branches draining into the common iliac vein such as the iliolumbar vein (a valveless vein that can bleed profusely).

    Having identified the origin of the internal iliac vein, pass 2.0 vicryl sutures around the short section of visible internal iliac vein as shown, so that it can be divided. By gentle traction on the rubber sloops controlling the external and the common iliac veins, we identify the internal iliac vein where the internal iliac vein is descending deep to the iliacus muscle towards the sciatic notch. Great care is taken not to inadvertently penetrate the vein when dissecting posteriorly or to rupture any posterior branches, which will cause ferocious bleeding.

    Having secured the 2.0 vicryl ties, the internal iliac vein is divided over a clip, using a no. 15 scalpel blade, again taking care not to inadvertently damage any branches or catch the internal iliac artery beneath.This is the most important step in the operation.

    This shows the (FN) femoral nerve, as it runs between the divided psoas and iliacus and proximally we can see evidence of the (LSP) lumbosacral plexus with branches running in towards the sciatic notch to form the sciatic nerve (L4-S3).

    Before dividing the femoral nerve, we inject some local anaesthetic (Marcain 0.25% plain) to anaesthetise it before dividing it sharply under traction, this is to give better pain relief and to reduce surgical stimulus when dividing the nerve.

    Having injected the nerve with local anaesthetic and allowed a few minutes for the local anaesthetic to take effect, the femoral nerve is divided at the level of the sciatic notch.The sciatic notch lies deep to the femoral nerve and the iliacus muscle.

    Having divided the femoral nerve and retracting the proximal cut end of psoas, one should identify the (IIA) internal iliac artery, running from medial to lateral towards the sciatic notch.It supplies the gluteal pedicle, which supplies the buttock muscles and abductors which are being amputated.

    Using Debakey forceps and Lahey’s forceps, the (IIA) internal iliac artery is grasped and dissected before division.

    Having identified the (S) sciatic nerve running into the (SN) sciatic notch, this is again injected with local anaesthetic and sharply divided over a clip.
    Take care not to inadvertently damage any of the local structures.

    The two cut ends of the (S) sciatic nerve are shown and we can see there is only a short distance before the nerve passes under the iliacus and into the (SN) sciatic notch.

    Continue the skin incision into the groin crease from the bony landmarks: public tubercle to the ischial tuberosity following the skin markings, taking care to avoid getting to close to the anus.Aim to preserve at least a 3cm margin from the anal border.

    The skin and fat are divided until we reach the (P) pubic bone, which is shown at the centre of the photograph.

    We have identified, using cautery, the front of the (P) pubic bone, posterior to which is the (R) space of Retzius in front of the bladder. An artery clip has been placed into the medial obturator foramen beneath the pubic bone.

    Divide the pubic bone.Having replaced the clip with a ring handle spike into the obturator foramen inferior to the pubic bone for protection, an osteotome is placed onto the surface of the bone to perform the osteotomy of the pubis. Care is taken not to inadvertently damage the corona mortis which lies posterior to the pubic bone, an arterial anastomosis between the external iliac artery and obturator artery (which pierces the obturator foramen to supply the adductor compartment of the thigh).

    Having divided the pubis continue the skin incision over the posterior ilium and towards the posterior superior iliac spineThis is marked on the skin with indelible marker.

    The skin incision is deepened in line with the incision, down to the fascia overlying the posterior superior iliac crest, which is shown with the forceps. There are no structures at risk during this superficial dissection.

    Divide the deep fascia over the medial aspect of the posterior iliac crest which reveals the cranial ilio-lumbar muscles inserting onto the posterior ilium.On the caudal side of the posterior ileum the gluteus maximus muscle arises. The paraspinal muscles are arranged in three layers: superficial, intermediate and deep. The superficial muscles (iliocostalis lumborum) insert onto the posterior ileum, which are divided in this step.

    Divide the iliolumbar muscles which are inserting onto the posterior ilium over an artery clip, to gain access to the posterior aspect of the sacroiliac joint.

    Having released the muscles off the medial surface of the posterior ilium and exposed the posterior superior iliac spine (PSIS), the dissection continues down towards the ischial tuberosity.Divide the gluteus maximus muscle as it arises from the sacrum to gain access to the ischiorectal fossa.

    The gluteus maximus muscle is divided in line with the skin incision, following the buttock crease towards the groin.This gains greater access to the ischiorectal fossa.

    Having divided the (GMAx) gluteus maximus muscle off the (S) sacrum, we then carefully divide the origin of the sacrospinous and sacrotuberous ligaments off the sacrum, which are the main stabilisers of the pelvic ring.

    Divide the origin of the sacrospinous and sacrotuberous ligamentsRelease the (ST) sacrotuberous (superficial) and (SS) sacrospinous (deep) ligaments. To divide these tough and broad ligaments safely, we insert an artery clip deep to the ligaments as shown, following the lateral border of the (S) sacrum which is marked for safety. The risk here is that we could inadvertently puncture into the rectum.

    Operation – 3

    The dissection moves laterally off the border of the sacrum as we progress distally, heading towards the ischial tuberosity as a landmark, again using the artery clip to protect us from the rectum beneath, we use cautery to divide the sacrotuberous ligament.

    Having completed our osteotomies, apart from the sacroiliac joint, attention turns to raising the pedicled fillet flap. The (EI) external iliac vessels can be seen passing under the inguinal ligament and an incision is made in line with these along the medial thigh, so that the vessels can be skeletonised and supply the calf musculature and flap. Also shown is the space of (R) retzius and the peritoneum overlying the bladder, the (FN) femoral nerve and (LFCN) lateral femoral cutaneous nerve of the thigh. The site of the pubic osteotomy has been packed with swabs.

    Dissect the saphenofemoral venous junction.Dissect out the saphenofemoral junction by identifying the long (SV) saphenous vein superficially, and trace this vein towards the saphenofemoral junction. It is desirable to preserve the saphenous vein for venous drainage of the fillet flap.

    Having skeletonised the (SV) saphenous vein, we have now exposed the saphenofemoral junction and the saphenous vein flows into the common femoral vein, before it passes beneath the inguinal ligament to become the (EI) external iliac vein as shown.

    The inguinal ligament is divided carefully using bipolar diathermy, cutting onto a large clip that protects the underlying vessels.The (IL) inguinal ligament overlies the junction of the external iliac vessels becoming the (FV) femoral vessels.

    Mark out the fillet flap incisionsA fillet flap incision is marked, the incision runs along the medial aspect of the thigh (i.e. over the femoral vessels that supply the flap), inferior to the patellar and along the tibial crest anteriorly and circumferentially around the distal tibial plafond just above the level of the malleoli as shown.

    Begin the skin incision for the fillet flap from the medial thigh passing inferior to the patellar and along the tibial crest to the ankle.

    As the subcutaneous border of the tibia is identified, the muscle of the anterior compartment is elevated from the bone supraperiosteally from the tibial tuberosity down to the tibial plafond.Essentially this flap retains as much skin and muscle from the calf as possible after resection of the tibia and fibula. Care is required to preserve vascularity at all costs: any loss of vascular supply threatens flap survival and likely return to theatre for flap revision.

    Skin incisions for the flap are continued around the distal tibia around the ankle circumferentially to complete the skin incisions for the flap.The incisions are deepened through the fascial compartments of the distal calf using cautery laterally and medially.

    The saphenous vein is cut and divided, as is the dorsalis pedis artery, at the level of the ankle to enable the flap to be elevated off the tibia. The peroneii are elevated off the fibula using a periosteal elevator as shown.

    The dissection passes posteriorly to divide transversely the peroneal muscles(as shown) before reaching the tendoachilles which is also divided.Viewed posteriorly: Once the soft-tissues are divided distally the flap dissection can rapidly progress proximally.

    To facilitate dissection, the tibia and fibula are osteotomised and the foot amputated.

    The cut distal tibia is then elevated out of the wound to facilitate proximal posterior dissection of the fillet flap.

    The anterolateral and deep posterior compartments are peeled off the proximal tibia.

    Care is taken to preserve the (ATA) anterior tibial artery and vein, as they pierce from the popliteal fossa posteriorly to anterior and by passing just inferior to the proximal tibio-fibular joint, having branched off the popliteal artery, into the popliteal vein.

    The remaining dissection around the medial aspect of the knee continues over the pes anserinus through skin and fat.

    The thigh dissection is now continued from the proximal thigh and groin, along the medial aspect of the thigh, following the course of the (S) sartorius muscle, which overlaps the femoral vessels. Sartorius arises from the anterior superior iliac spine and inserts onto the pes anserinus. The vascular supply to sartorius is segmental because it is the longest muscle in the body and therefore derives blood supply from several sources:
    Proximal third: branches of the superficial femoral artery, profunda femoris artery
    Middle third: branches of the superficial femoral artery
    Distal third: branches of the superficial femoral and descending geniculate arteries
    Because of the segmental blood supply, the sartorius is suitable as a proximally or distally based flap in plastic surgery as covering of bone defects of the hip, femur and knee.

    Having completed the skin incision and gone through the deep fascia, identify the (S) sartorius muscle, running along the medial aspect of the thigh, down towards the pes anserinus.This is an important landmark to identify the femoral vessels which run beneath the sartorius muscle.

    Having identified and reflected the sartorius, the femoral vessels are dissected from proximal to distal following their course from the femoral triangle.This passes through the adductor canal (Hunter’s/sub-sartorial canal) to enter the posterior thigh and popliteal fossa.

    Perforating branches of the vessels piercing through the adductor fascia to feed the vastus medialis are carefully ligated, to skeletonise the femoral artery and vein.

    Having released the adductor tendon, that forms the roof of the adductor canal, the vessels start to emerge from the wound. The adductor canal contains the femoral artery, femoral vein (posterior), nerve to the vastus medialis (motor) and the saphenous nerve (sensory) (which are both branches of the femoral nerve). The adductor canal lies in the middle third of the medial thigh and it’s boundaries are: anteromedially the sartorius muscle, posteriorly the adductors longus and magnus and laterally the vastus medialis muscle.

    The femoral vein is slooped for protection; also seen running with the femoral vein is the nerve to vastus medialis which is divided as it is redundant.

    Having dissected the femoral vessels through the adductor canal into the popliteal fossa, the knee joint is disarticulated.The adductor magnus is released off the adductor tubercle from the medial (DF) distal femoral metaphysis as shown.

    The medial gastrocnemius is now released from it’s origin posterior (DF) distal femur, taking care not to damage its pedicle from the popliteal artery and vein.Mobilise the origin of the gastrocnemius, which will make up the bulk of the fillet flap.

    The joint capsule is divided posteriorly having divided the ACL as shown, to disarticulate the knee joint to facilitate removal of the tibia and access to the lateral gastrocnemius.

    Operation – 4

    Having released the posterior knee capsule, the (T) tibia is elevated out of the wound.This reveals the (PT) patellar tendon and the (P) patella, which is now divided to remove the tibia from the wound.

    Both the medial and lateral gastrocnemius have now been divided from the posterior aspect of the (F) femur.At this point this means that the flap is almost completely mobilised from the bone.

    The slooped (FP) femoral pedicle consisting of the femoral artery and vein are now mobilised out of the thigh from distal to proximal. The sloop allows the vessels to be gently lifted out of the wound to identify branches posteriorly.

    Mobilise the pedicle of the fillet flap, this can now be elevated out of the wound and off the thigh.

    Here we can see the pedicled fillet flap with the (FP) femoral pedicle (femoral artery and vein) becoming the popliteal artery and vein, as well as the (SV) saphenous vein that is draining the calf musculature.

    The medial side of the flap is shown, which has good vascularity and should enable wound coverage with healthy well vascularised tissue.

    The flap is placed into an abdominal or bowel bag with a warmed soaked abdominal pack to stop the flap drying out.
    It is then placed in front of the patient’s abdomen with the pedicle out of the pelvic wound as seen in the photograph.

    Returning to the pelvic exposure, the external iliac and common femoral vessel pedicle is seen leaving the retroperitoneal and running into the bowel bag ex-vivo (1)

    The ring handled spike bone lever is placed through the sciatic notch from inside to outside, to identify the top of the sciatic notch, prior to osteotomy of the sacroiliac joint, which is the last remaining osseous cut to be performed.

    Using the osteotome to find the inside of the sacroiliac joint, the osteotome is inserted into the fibrous joint and gently tapped with a mallet to divide the sacroiliac joint, the last joint to be divided. The assistant is supporting the posterior ilium and allowing the weight of the leg and pelvis to externally rotate off the sacrum.

    Having divided the sacroiliac joint, inside the sciatic notch becomes more visible, any residual nerve roots and muscles would need to be divided swiftly at the stage, to avoid any bleeding.

    By supplying gentle traction to the divided posterior ilium the pelvic floor muscles are now divided from the sciatic notch, down to the space of retzius in front of the bladder, taking care not to damage the rectum, prostate, ureter or bladder.

    By dividing the pelvic floor from proximal to distal, this allows the posterior ilium to swing away from the sacrum and the assistant to insert a hand underneath the buttock to support the amputated leg.
    Here the abdominal wall can be seen being stretched as this takes place, which maintains the tension on the pelvic floor to be divided using cautery, along the line of the surgeon’s thumb in this photograph.

    Divide the pelvic floor muscles to complete the amputation.Using the artery clips under the pelvic floor, the remaining pelvic floor muscle (elevator ani and coccygeus) are divided to complete the amputation.

    The specimen lies on the back table, showing the tibia and the femur and the hemipelvis
    This is sent for histological analysis to confirm the complete resection of the tumour with wide margins.
    The results confirmed a wide resection of this rare primary malignant bone tumour.

    The fillet flap is now aligned with the pelvic wound and the vessels are coiled to preserve flow and to prevent any kinks, due to the acute shortening of the femoral vessels during the procedure.

    A layered repair of the pelvic wound is performed using the myofasciocutaneous flap which is sutured in three layers to reconstruct the abdominal wall, pelvic floor the paralumbar muscles.This looks pink and healthy and vascularised in this photograph.

    Final skin closure is performed using 1.0 vicryl deep dermal continuous suture.

    Skin closure is complete using a continuous 2.0 nylon suture as shown, or skin clips are acceptable.

    An incisional vacuum dressing is applied at 100mmHg and two drains are passed out through the abdominal wall draining the retroperitoneal space.

    Post Operative

    Mechanical and venous thromboembolism prophylaxis using thromboembolic compression stockings for 6 weeks with flowtrons or foot pumps whilst in bed and chemical thromboprophylaxis (low molecular weight heparin) for 28 days, (see Lex et al. Venous Thromboembolism in Orthopaedic Oncology. Bone Joint J 2020;102-B(12)1743:–1751.)
    Up titrate the dose of pregabalin and according to levels of phantom limb pain.
    Await histological analysis.
    Check bowel sounds before recommencing light diet in 24-36 hours.
    Removal of sutures at two weeks.
    Wound review on ward after seven days with plastics team.
    Routine high grade bone sarcoma surveillance (three monthly CXRs for two years with clinical examination, then six monthly until year five, ten annually until ten years).



    Recommended Reading

    British Orthopaedic Association guidance is very clear: prodromal pain and injury mechanisms not in keeping with the fracture sustained are indicators of pathological fractures, which should be investigated thoroughly to identify the potential malignant, infective or metabolic cause. This is to prevent inadvertent surgery that may compromise a potential curative resection, leading to more extensive and morbid surgery.
    Hindquarter amputations are the most extensive procedures in the armoury of orthopaedic oncologists for controlling pelvic and proximal femoral tumours and certainly not undertaken lightly, nor in the absence of a multi-disciplinary team discussion. This is a challenging discussion to broach with patients usually aided with appropriate imaging to enable the patient to visualise the extent of the tumour.
    Outcomes from this procedure are poor: the morbidity and mortality are higher than any other orthopaedic procedure, 30-day mortality is 1% at our institution (Kiiski et al. Surgical and oncological outcomes after hindquarter amputation for pelvic sarcoma. Bone & Joint Journal 2020;102:788-794). One in two patients suffer a complication and one in four require further surgery.
    The most frequent indication for HQA is to offer resection of bone or soft-tissue tumours with curative intent, meaning that patients are carefully selected particularly if they have staging imaging indicative of pulmonary metastases meaning the procedure would be palliative (Grimer et al. Hindquarter amputation. Bone & Joint Journal 2013; 95-B:1:127-131). Palliative hindquarters are associated with a 30-day mortality rate of 1/3.
    Controversy and concern about this operation, rightly, persists in surgical literature: in patients younger than 65 years with localised disease (non-metastatic) it remains an acceptable curative surgical option, although authors have urged caution in patients aged greater than 65 years with larger tumours (>15cm) who have worse overall survival after HQA (van Houdt, WJ et al. Oncologic Outcome and Quality of Life After Hindquarter Amputation for Sarcoma: Is it Worth it?. Ann Surg Oncol 2018;25:378–386).

    Reference

    • orthoracle.com

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