Lower Limb Pain & Trauma

 

Lower limb pain and trauma

• Hip pain

  Greater trochanteric pain syndrome

  • Aka trochanteric bursitis.
  • Commonest in women age 40-60, but also occurs in younger people who are physically active.
  • Pain in area of greater trochanter, may radiate down lateral leg. May be worse at night, especially if lying on affected side.
  • On examination, tender greater trochanter, pain on internal/external rotation, and positive Trendelenburg test (see Hip examination).
  • Management: avoid aggravating activities, apply ice pack, simple analgesia, weight loss if obese. Steroid injection if these measures fail.
  • Usually self-resolves.

  Other causes

  Pain syndromes:

  • Hip impingement syndrome: groin pain linked to sports. Pain on internal rotation.
  • Sports hernia (aka athletic pubalgia): chronic groin pain in athletes, reproduced by hip extension and rotation, along with dilation of superficial ring of inguinal canal. Likely due to strains/tears in tendons and muscles.

  Other causes:

  • Osteoarthritis (OA) or inflammatory arthritis: limited range of movement, especially internal rotation.
  • Avascular necrosis of the femoral head: can be idiopathic or secondary to trauma, alcohol, or steroid use. Confirmed on X-ray or MRI (earlier).
  • Meralgia paresthetica (see Lower limb mononeuropathies).
  • Referred back pain or knee pain.
  • Fracture, infection, or malignancy are potential serious causes, as with any joint pain.

• Proximal femoral fracture

  Definition

  • Aka hip fracture or fractured neck of femur, though the latter term is only anatomically accurate for intracapsular fractures.
  • Typically refers to fractures up to 5 cm below the lesser trochanter, with those beyond classed as femoral shaft fractures.

  Causes

  • Commonly due to a fall in a patient with underlying osteoporosis.
  • In the absence of osteoporosis, a high energy impact is usually required.

  Signs and symptoms

  • Groin pain and unable to weight bear.
  • Shortened and externally rotated leg.

  History and examination

  History:

  • Determine mechanism of injury: was it a low energy fragility fracture?
  • Establish baseline function in terms of walking and ADLs. Will guide physio and OT input.

  Examination:

  • Check for tenderness by pressing down in groin around joint area. Not necessary if diagnosis obvious and patient in pain. Similarly, only move leg in so far as tolerated.
  • Palpate pubic rami to check for pubic rami fracture.
  • Check and document neurovascular status. In compartment syndrome of the thigh (rare), the deep peroneal nerve may be affected; check sensation in 1st and 2nd toe web space, which DPN supplies.

  Investigations

  X-ray of pelvis (AP) and lateral hip:

  • Disrupted Shenton's line.
  • Leg is shortened – higher lesser trochanter on fracture side – and externally rotated – more prominent lesser trochanter on fracture side.
  • Determine if intracapsular – above the intertrochanteric line – or extracapsular – either intertrochanteric or subtrochanteric. If intracapsular, is it displaced (Garden 3-4) or non-displaced (Garden 1-2)? Most fractures are intracapsular or intertrochanteric, with subtrochanteric fractures (and femoral shaft fractures) suggesting high energy trauma (e.g. car crash) or pathological fractures.
  • Usually in 2 pieces, but can be more.
  • Usually transverse or short spiral fractures, but intertrochanteric fractures are oblique.

  Pre-surgical investigations:

  • Bloods: FBC, U+E, coag, group and save.
  • ECG, CXR.

  If cancer suspected e.g. trochanteric fracture:

  • Full-length femoral imaging.
  • Bone profile, LFTs, PSA, myeloma screen.

  Management

  Initial

  • Analgesia. Consider nerve block.
  • Nil by mouth.
  • DVT and antibiotic prophylaxis.
  • Stop any warfarin and aim for INR <1.5.

  Surgery

  Main benefits of surgery are to prevent avascular necrosis (AVN), non-union, and complications of immobility such as DVT. Better outcomes if quick repair i.e. <24 hours.

  Replacement arthroplasty:

  • Used for most displaced intracapsular fractures. These fractures carry a high risk (50%) of AVN of the femoral head, as the circumflex arteries which supply the head sit on the femoral neck.
  • Some centres also use it for non-displaced intracapsular fractures, although the risk of AVN is low (10%).
  • Hemiarthroplasty, which involves replacement of the femoral head, is the commonest procedure.
  • Total hip replacement – which has a better functional outcome – is preferred if the patient is mobilizing independently (up to 1 stick) and has a good functional status, or if they have osteoarthritis.

  Screws:

  • Dynamic hip screw (DHS) provides internal fixation with a screw attached to a plate. Allows controlled sliding of the femoral head. Multiple, cannulated hip screws are another option, used for intracapsular fractures.
  • Indicated in extracapsular and non-displaced intracapsular fractures, where there is a low or no risk of AVN.
  • Also indicated in displaced intracapsular fractures in younger patients (age <50), who would need to have a further joint replacement in future if they had arthroplasty. Therefore preserving their own hip is optimal. Downside is that they may need to be on crutches for months to allow healing.

  Intramedullary hip screw (aka intramedullary hip nail):

  • Indicated in subtrochanteric and femoral shaft fractures.

  Non-surgical management:

  • In a very small number of cases – immobile patient, undisplaced fracture, unfit for surgery – this approach can be taken.

  Post-op

  • Early mobilisation and rehab with physio and OT.
  • Think about pathological fractures, especially with low energy injuries and extracapsular fractures. Screening bloods: FBC, U&E, LFT, bone, TFT, PTH, vitamin D, B12 and folate.

  Outcomes and surgery complications

  Complications:

  • Preoperative: neurovascular damage from the fracture.
  • Intraoperative: blood loss, fat embolism, poor reduction, periprosthetic fracture (post-arthroplasty).
  • Postoperative: infection, poor bone healing, non/malunion, unequal leg length (post-arthroplasty), DVT.

  Mortality:

  • 10% at 30 days.
  • 30% at 1 year.

• Non-traumatic knee pain

  Causes and presentations

  Pain syndromes

  Most can be unilateral or bilateral.

  Osgood-Schlatter disease:

  • Focal tibial tubercle pain in teenagers, worse with activity and kneeling.
  • On examination, may have bony enlargement of tibial tuberosity, and pain with extension against resistance.

  Osteochondritis dissecans:

  • Knee pain, worse with activity, commonly in teenagers.
  • May report locking or giving way.

  Patellofemoral pain syndrome:

  • Anterior knee pain, worse with taking stairs or prolonged sitting/squating, and sensations of stiffness or giving way.
  • Onset in teeans and early adulthood, commoner in females.

  Iliotibial band syndrome:

  • Aching/burning localised to lateral femoral epicondyle, radiating to thigh/hip, occurring in runners.
  • Symptoms reproduced by Ober's test.

  Pas anserinus pain syndrome:

  • Infero-medial knee pain, including at night and when rising.
  • Previously known as anserine bursitis, but true bursitis is in fact very rare.

  Pre-patellar bursitis

  • Aka housemaid's/carpetlayer's knee.
  • Anterior knee pain and boggy swelling, typically due to prolonged pressure from kneeling.
  • In rare cases, there is infection (septic bursitis), typically with Staph. aureus.

  Others

  • Baker's cyst: popliteal swelling and ache. Rupture may lead to acute calf swelling.
  • Arthritis: osteoarthritis, inflammatory, crystal, septic.
  • Bone or soft tissue cancer.

  Imaging

  Not generally indicated with pain syndromes, with the exception of osteochondritis dissecans.

  Management of bursitis and pain syndromes

  Almost all follow the same broad principles:

  • Minimize/modify aggravating activities, but remain as active as tolerated. Protective padding may help for pre-patellar bursitis and Osgood-Schlatter.
  • Manage pain and swelling: analgesia, ice, compression, elevation.
  • Physiotherapy, typically starting with advice leaflets/websites with home exercises.
  • Steroid injections if other measures fail.
  • Most self-resolve, but may take long time (e.g. up to 1-2 years in Osgood-Schlatter).

  If septic bursitis suspected, aspirate fluid and give antibiotics.

• Acute knee trauma

  Injuries and mechanisms

  Soft tissue (mainly ligament and meniscal injuries):

  • Inward (valgus) blow (commonest) → injures medial collateral ligament then anterior cruciate ligament (ACL) and medial meniscus. If all 3 occur, known as 'the unhappy triad of O'Donoghue'.
  • Outward (varus) blow → injures lateral collateral ligament and/or ACL.
  • Anterior or posterior blow → injures cruciate ligament.
  • Weight bearing + rotation → injures menisci.

  Fractures:

  • Patella fracture, typically from direct blow to flexed knee e.g. dashboard, fall.
  • Tibial plateau fracture, typically from axial load plus valgus force e.g. car crash including bumper vs. pedestrian.

  Presentation

  • Pain and tenderness.
  • Classic history with ACL is audible 'pop' at time of sporting injury, carried off field, followed by instability and swelling.
  • Meniscal injury suggested by locking and giving way.

  Investigations

  Stress testing examination:

  • For ligament/meniscal injuries, to distinguish complete from partial tears.
  • Includes Lachman's test for ACL, and McMurray's test for meniscal injuries (see also Knee examination).

  Imaging:

  • X-ray to look for fracture if any of the Ottawa Knee Rules are positive after acute trauma: age ≥55, isolated patella tenderness, fibular head tenderness, unable to flex to 90°, unable to weight bear.
  • CT if tibial plateau fracture suspected, as only sign on X-ray may be lipohaemoarthrosis.
  • MRI not routinely indicated, but may be needed for severe or non-resolving soft tissue injuries.

  Management

  Soft tissue:

  • General initial management is analgesia and RICE: Rest, Ice, Compression (elastic bandage/wrap), Elevation.
  • Subsequent: splinting if unstable, physiotherapy.
  • Surgical referral for ACL or severe/complex meniscal injuries. For example, if unresponsive to physiotherapy, ACL might require repair using tendon graft (usually autograft from own patellar tendon or hamstring).

  Fracture:

  • Minimally-displaced: brace in extension (patella) or hinged knee brace (tibial plateau).
  • Displaced: fixation, usually ORIF.

• Non-traumatic ankle and foot pain

  Achilles tendinopathy

  • Aka achilles tendinitis, though we rarely have objective evidence of inflammation.
  • Risk factors: co-morbidities (obesity, type 2 diabetes, ankylosing spondylitis), medications (quinolones, statins), family history.
  • Presents with posterior heel pain. On examination, achilles tendon may be thickened but not necessarily tender. Pain reproduced with dorsiflexion and on hopping.
  • Manage with simple analgesia, minimize aggravating activities but remain active and try self-directed strengthening exercises. Advise symptoms may last up to 2 years, though failure to improve after 3-6 months should prompt surgical referral.

  Plantar fasciitis

  • Affects 1 in 10 people over 50, but can occur at any age. Obesity is a risk factor.
  • Presents with plantar heel pain, which may be worse on taking first few steps in the morning or after sitting. Bilateral in 30%.
  • On examination, tender at insertion of plantar fascia to calcaneum.
  • Manage initially with simple analgesia, minimize aggravating activities but remain active and try self-directed exercises and stretching, and consider orthotics. Steroid injections provide up to 4 weeks relief in resistant disease. Advise symptoms usually resolve within 1 year.

  Other causes

  • Posterior heel pain: retrocalcaneal bursitis (swollen and tender), posterior ankle impingement (worse on plantar flexion), achilles tendon rupture or partial tear (sudden pain and tenderness, calf squeeze test positive).
  • Arthritis: osteoarthritis, inflammatory, crystal, septic.
  • Vascular: peripheral vascular disease, DVT.
  • Peripheral neuropathy.

• Ankle fractures

  Definition and causes

  • Most commonly an inversion (supination) injury to the lateral malleolus (distal fibula).
  • Eversion (pronation) injuries to the medial malleolus (distal tibia) are less common, due to the strong deltoid ligament.

  Classification

  Weber classification of fibula fracture is based on relation to the tibiofibular syndesmosis:

  • A: distal to syndesmosis. Usually stable.
  • B: at syndesmosis, which is intact or partially torn
  • C: proximal to syndesmosis, which is torn.

  Investigations

  Ankle XR: AP, lateral, and oblique (mortise) view.

  Management

  • Most are managed with a walking boot or below knee cast to midfoot; continue 4-6 weeks.
  • ORIF needed if unstable (inc. dislocated, bimalleolar), displaced, open, and/or Weber C (and some Weber B).

• Ankle sprain

  Definition and classification of sprains

  • A sprain is stretching or tearing of the ligament. The equivalent injury in muscles or tendons are 'strains'.
  • Sprains are classified as grade 1 (stretch with minimal tears), grade 2 (partial tearing), or grade 3 (complete rupture).

  Presentation

  General:

  • Ankle pain and tenderness.
  • There may be swelling, bruising, and difficulty weight bearing, especially if grade 2-3.
  • Joint laxity (grade 2) or significant instability (grade 3).
  • Common in athletes and dancers.

  Low ankle sprain (90%):

  • Inversion, most commonly in plantarflexion → lateral ligament sprain, usually anterior talofibular ± calcaneofibular.
  • Eversion → deltoid ligament sprain. However, given deltoid strength, eversion more commonly causes avulsion fracture of medial malleolus.

  High ankle sprain (10%):

  • External rotation (or eversion + dorsiflexion) → injury to the syndesmosis, which joins the tibia and fibula.

  Investigations

  Stress testing:

  • Anterior talofibular ligament sprain → laxity in plantar flexion or +ve ankle anterior draw test.
  • Calcaneofibular ligament sprain → +ve inversion stress test.
  • High ankle sprain → pain on external rotation/dorsiflexion, pain on squeezing tibia and fibula at midcalf.

  Ottawa ankle rule on when to X-ray for suspected fracture:

  • Ankle XR + foot XR if inability to weight bear (i.e. can't even limp) immediately and in ED.
  • Ankle XR if tender within 6 cm of medial/lateral malleolus.
  • Foot XR if tender at 5th metatarsal base or navicular area.

  High ankle sprain XR:

  • Widening of tibiofibular clear space (>6 mm).

  Management

  • RICE – Rest, Ice, Compression (elastic bandage/wrap), Elevation – to reduce swelling.
  • Ankle immobilization not needed for grade 1, but grade 2 may need a splint (aka brace) and grade 3 a below-knee cast.
  • Rehabilitation and mobilization as early as comfort allows, with crutches until gait is normal.
  • Surgery indicated if there is continued pain and instability, with reconstruction or tendon transfer.
  • High ankle sprains require non-weight-bearing cast or boot for several weeks, or syndesmotic screw fixation if there is instability or continued pain.

• Lower limb mononeuropathies

  Lateral cutaneous nerve of thigh lesions (L2-3)

  Causes:

  • Compression on exiting pelvis beneath inguinal ligament, just medial to the ASIS (meralgia paraesthetica).
  • Often due to obesity/pregnancy pressing down on the inguinal ligament, or tight clothing.

  Presentation:

  • Antero-lateral burning thigh pain and/or numbness.

  Sciatic nerve lesions (L4-S3)

  Causes:

  • Lumbar radiculopathy due to slipped disc (common), degeneration, tumour, or trauma.

  Presentation:

  • Back pain.
  • Leg pain radiating top to bottom.
  • Much less commonly, motor features: foot drop, weak hip abduction (distinguishing it from peroneal compression).

  Common peroneal nerve lesions (L4-S1)

  Background:

  • One of the terminal divisions of the sciatic nerve (anterior compartment).
  • Aka common fibular nerve.
  • In turn divides into the deep and superficial peroneal nerve.

  Causes:

  • Compression against fibula due to leg-crossing or squatting, fracture, or plaster casts.

  Deep peroneal nerve lesion presentation:

  • Weak ankle dorsiflexion (foot drop) and toe dorsiflexion, and foot eversion.
  • This is the commonest cause of foot drop.
  • Also numb in first web space.

  Superficial peroneal nerve lesion presentation:

  • Weak ankle eversion.
  • Numb in anterolateral lower leg and foot dorsum (except web space).

  Common peroneal nerve lesion presentation:

  • Any mix of the above.

  Tibial nerve lesions (L4-S3)

  • The other terminal division of the sciatic nerve (posterior compartment).
  • Cause: compression behind the medial malleolus (tarsal tunnel syndrome).
  • Presentation: weak ankle plantarflexion and inversion, and weak toe plantarflexion. Numb sole of foot.