Groin/knee Pain and A New Limp — Free SCA Practice Case
Teenage boy with groin/knee pain and a new limp
Station Timer
Golden Minute
Initial Introduction
•Introduce yourself
•Ask an open question — "How can I help you today?"
•Listen — don't interrupt
•Catch early cues
Data Gathering
History, ICE & Diagnosis
Clinical Management
Diagnosis, Plan & Decisions
Safety Net
Follow-up & Close
Five cases are free: a live 12-minute consultation with an AI patient each, marked, and no card.
Materials for Candidate
Please review before starting the consultation
Full Name
Liam Davies
Age
13 years
Consultation Type
VideoAge
13
Accompanying
Karen Davies (Mother)
Situation
Video Consultation.
Reason for Encounter
"Liam has been limping for a few weeks and complaining of an aching left knee. It got suddenly worse yesterday, and now he is struggling to walk."
Medical Records
- ●PMH: Mild childhood asthma.
- ●Medications: Salbutamol inhaler PRN.
- ●Allergies: NKDA.
- ●Recent Notes: Last seen 2 years ago for an asthma review. BMI historically tracked >91st centile.
Patient Script
For the friend playing the patient role
Character Overview: You are Liam, a 13-year-old boy. For the past three weeks, you've had a dull ache in your groin and thigh, but yesterday, while doing heavy barbell squats, you felt a sudden, sharp pain deep in your hip/groin that shot down to your knee. You can now barely put any weight on it. You are hiding a deep source of shame. You are being severely bullied at school for your weight. In a desperate attempt to "get buff" and stop the bullying, you've been secretly going to a local unstaffed gym with an older cousin and lifting extremely heavy weights with terrible form. You are terrified that if you tell the doctor how it happened, your mum will find out, ban you from the gym, and the bullying will continue forever. You will not volunteer the gym, the bullying, or the fact that the pain actually started in your hip unless the doctor speaks directly to you (not just your mum), builds rapport, and gently asks about your life at school or exactly what you were doing when it worsened.
Consultation Flow & Responses:
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The Opening
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Karen (Mother): "Hi Doctor. I've brought Liam in because he's been complaining about his left knee for a few weeks. I thought it was just growing pains, but since yesterday he's been limping terribly. He won't even walk to the car properly."
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If the doctor asks Liam an open question: "Yeah. My knee just hurts. Can I just get a bandage or something?"
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Data Gathering (The Layers)
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Layer 1: The Distracting Symptom (The Knee):
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Liam: "It's an ache right at the front of the knee. It throbs."
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Liam: "No, I didn't twist the knee. It didn't pop or swell up."
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Layer 2: Uncovering the True Source (The Hip Trap):
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If asked if the pain is anywhere else (groin/thigh): Liam: "I guess my thigh hurts too. And right up at the top of my leg, in the crease. But mostly it's the knee."
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If asked to describe the limp: Karen: "He sort of waddles. His left foot points outwards like a duck when he walks now." (Classic sign of external rotation in SUFE).
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Layer 3: The Trigger Event:
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If asked what he was doing yesterday when it got worse: Liam: Looks nervously at his mum. "Just... hanging out. Walking around the park." (He is lying. The doctor needs to gently probe this).
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Layer 4: ICE & The Core Revelation (The Hidden Bullying) - ONLY REVEAL IF ASKED DIRECTLY & EMPATHETICALLY:
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If the doctor asks: "Liam, you seem really worried. Is there something else going on?" or asks the mother to briefly step outside for privacy:
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Reaction (The Reveal): You look down at your shoes, your voice shaking. "Please don't tell my mum to stop me going. I was at the gym doing heavy squats. The lads at school call me 'fat boy' every day, they shove me in the corridors. If I get big and muscular, they'll stop. I felt a massive crunch in my hip when I lifted the bar yesterday. If you tell my mum, she'll ban me from the gym and I'll be a target forever."
ICE — Ideas, Concerns, Expectations
These surface only if the candidate directly explores Liam's perspective. Liam does not volunteer this information unprompted.
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Ideas: Liam has no real idea what's wrong — he assumes it's something to do with his knee, maybe a pulled muscle or a strain. He doesn't connect the hip/groin pain to the knee problem. If the bullying and gym context have been disclosed, he might quietly ask, "Did I break something doing the squats?" but he has no concept of a growth plate injury.
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Concerns: Liam's overwhelming concern is not the pain itself — it's the social consequences. He is terrified that being told to stop the gym will leave him defenceless against the bullies. Underneath that, if gently pressed, he is also frightened that something serious is wrong with his leg — "Will I ever be able to do sports again?" — but he will suppress this fear unless he feels safe enough to voice it.
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Expectations: Liam came in hoping to get something simple — a bandage, some painkillers, and to be sent home quickly before too many questions are asked. If the hip problem has been identified and he understands the seriousness, his expectation shifts: he wants reassurance that he'll recover fully and be able to exercise again, and he desperately wants the doctor to help him with the bullying situation without just telling his mum everything.
If Asked — Medical History and Medications
Actor guidance for items from the medical record that the candidate may ask about. Liam or Karen respond as indicated.
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If asked about asthma: Karen: "He was diagnosed when he was about five, but he's really grown out of it. He hasn't had an attack in years." Liam: "I don't really use the inhaler. I think it's somewhere in my school bag but I haven't needed it."
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If asked about the salbutamol inhaler specifically: Liam: "I've got one somewhere but I never use it. Maybe once or twice in PE last winter when it was really cold, but nothing recently."
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If asked about allergies: Karen: "No, no allergies that we know of."
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If asked about his weight or BMI: Karen: "He's always been a bigger boy. The health visitor mentioned it a few times when he was younger. We've tried to be more careful with portions but it's hard — he's a growing lad." Liam: Looks uncomfortable and says nothing, or shrugs.
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If asked when Liam was last seen by a doctor: Karen: "It must have been about two years ago for his asthma check-up. He's been fine since then — no real reason to come in until now."
Social History and Lifestyle Impact
Actor guidance — volunteered naturally in conversation, not delivered as a monologue. Some of this content overlaps with the reveal in Layer 4 and should be calibrated accordingly: the school and lifestyle details below can be shared openly, but the bullying and gym details remain gated behind the Layer 4 rapport conditions.
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School and daily life: Liam is in Year 8 at a local secondary school. He is quiet and keeps to himself — he doesn't have a wide friendship group. He spends a lot of time in his room on his Xbox. Karen, if asked, will say: "He used to love football when he was younger but he stopped going to training about a year ago. He doesn't really do much after school now — just stays in his room." Liam, if asked about hobbies: "I play games. That's about it." He will not mention the gym unless the Layer 4 conditions have been met.
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Lifestyle impact of the current condition: Since yesterday, Liam has been unable to walk properly. Karen: "He couldn't get up the stairs last night — his dad had to help him. He didn't sleep well because every time he turned over it hurt. This morning getting into the car was a nightmare — he couldn't swing his left leg in." Liam, if asked directly: "I can't do anything. I can't even walk to the toilet without it killing me. And there's no way I can go to school like this." (Note: the inability to attend school carries particular weight given the hidden bullying context — Liam may feel secretly relieved but won't say so.)
If Asked — Associated Symptoms
Actor guidance for associated symptoms a thorough candidate should enquire about in a presentation of acute-on-chronic hip pain in an overweight adolescent. Informed by NICE CKS (Hip pain in children) and British Orthopaedic Association / Royal College of Paediatrics and Child Health guidance on SUFE.
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If asked about fever or feeling unwell: "No, I don't feel ill or anything. No temperature."
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If asked about night pain or pain at rest: "It aches all the time now, even when I'm sitting. Last night was the worst — it woke me up when I rolled over."
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If asked about pain in the other hip or leg: "No, it's just the left side. The right one's fine."
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If asked about back pain: "No, my back's alright."
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If asked about numbness, tingling, or pins and needles in the leg or foot: "No, nothing like that. It just hurts."
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If asked about difficulty with bladder or bowel function: "No, that's all normal."
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If asked about swelling, redness, or warmth around the hip or knee: "No, it doesn't look swollen or red. It just hurts deep inside."
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If asked about clicking, locking, or giving way: "It doesn't click or lock, but it does feel like my leg might give way if I put too much weight on it."
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If asked about any rash: "No, no rash."
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If asked about recent illness or infection (e.g. sore throat, cold): "No, I've been fine otherwise. No cold or anything."
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If asked about weight loss or appetite changes: Karen: "No, his appetite's the same as always — if anything he eats more than ever." Liam shrugs.
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If asked about fatigue or tiredness: "I'm always a bit tired but no more than usual."
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If asked about easy bruising or bleeding: "No, nothing like that."
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If asked about any previous hip problems or injuries: "No, never had any problems before the last few weeks."
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If asked about family history of hip problems or bone conditions: Karen: "Not that I know of. No one in the family has had hip replacements or anything like that — not until they were really old anyway."
Negotiation & Collaborative Management Plan
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If the Doctor only examines the knee and diagnoses a knee strain:
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Reaction (Liam): "So the knee is just strained? Okay, let's go Mum." (Note: Candidate critically fails for missing referred hip pain and sending an unstable SUFE home).
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If the Doctor demands he immediately stops going to the gym without addressing the bullying:
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Reaction (Liam): Angry and defensive. "You can't stop me! You don't know what it's like at school! I'm not stopping!"
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If the Doctor diagnoses a hip problem (SUFE) and says he needs to go to A&E:
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Reaction (Karen): Shocked. "A&E?! For a limp? Can't we just get an X-ray here next week? He has school tomorrow."
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If the Doctor explains the weight and the bone plate slipping:
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Reaction (Liam): "So my bone actually snapped because I'm too heavy? Will I ever be able to do sports again?"
Safety Netting / Follow-up
- ●If the Doctor insists on strict non-weight bearing (e.g., using a wheelchair to leave the surgery):
- ●Reaction (Karen): "A wheelchair? Is it really that fragile? Okay, we won't let him walk on it at all."
Mark Scheme
Domain 1: Data Gathering and Diagnosis
Domain 2: Clinical Management and Medical Complexity
Domain 3: Relating to Others
Clinical Learning Points
Diagnostic Distinction: SUFE vs Common Mimics
- ●Slipped Upper Femoral Epiphysis (SUFE) — also termed SCFE (Slipped Capital Femoral Epiphysis) — is a displacement of the proximal femoral epiphysis posteriorly and inferiorly off the femoral metaphysis through the hypertrophic zone of the growth plate. It is biomechanically equivalent to a Salter-Harris Type I fracture.
- ●The critical differentials in an overweight adolescent with hip/knee pain are Perthes disease (avascular necrosis of the femoral head, typically ages 4–8, more insidious onset), septic arthritis (fever, systemically unwell, acutely restricted and painful movement in all planes), and transient synovitis (usually younger child, afebrile, resolves within weeks).
- ●SUFE is distinguished by the combination of: pubertal age group, obesity, chronic prodrome of groin/thigh ache, acute deterioration to inability to weight bear, and the characteristic external rotation deformity on examination.
The Referred Knee Pain Trap
- ●Over 15–20% of children with a hip disorder — including SUFE, Perthes disease, and septic arthritis — present with knee or distal thigh pain only, with no spontaneous complaint of hip or groin pain.
- ●Referred pain travels via sensory branches of the obturator nerve and femoral nerve, which innervate both the hip capsule and the knee joint.
- ●Golden Rule: Any child with unexplained knee pain, a limp, or a painful gait must have their hip actively examined — check specifically for loss of internal rotation (earliest sign) and for the external rotation posture at rest. Do not accept a normal knee examination as the endpoint in this age group.
Risk Factors
- ●Obesity is the single most important risk factor: increased body mass produces abnormal shear stress across the physeal plate, particularly during periods of rapid growth. BMI at or above the 91st centile substantially elevates risk.
- ●Pubertal growth spurt destabilises the physis hormonally and structurally; this is why SUFE is almost exclusively a condition of adolescence (boys 10–15, girls 8–13).
- ●Endocrine disorders — hypothyroidism, growth hormone excess, hypogonadism — should be considered when SUFE occurs outside the typical age range or in a non-obese child; these weaken the physeal plate independently of mechanical load.
- ●High-load mechanical stress (as in this case: unsupervised heavy barbell squats) can precipitate acute displacement on a background of chronic stable slippage.
Stable vs Unstable SUFE — A Critical Distinction
- ●Stable SUFE: The child can still partially weight bear, even with pain and a limp. This represents a chronic or subacute slip. Risk of avascular necrosis is low (~0–10%).
- ●Unstable SUFE: The child cannot weight bear at all. This represents an acute or acute-on-chronic displacement and is a true orthopaedic emergency. Risk of avascular necrosis of the femoral head rises to 20–50%, with permanent joint destruction as a consequence.
- ●Liam's presentation — three weeks of prodromal groin ache followed by sudden inability to weight bear after a high-load event — is the archetypal acute-on-chronic unstable SUFE. This distinction drives the urgency of the management response.
Immediate Primary Care Management
- ●Strict non-weight bearing from this moment: Do not allow the patient to walk out of the consulting room. Arrange a wheelchair immediately. Every step risks further displacement and vascular injury to the femoral head.
- ●Same-day emergency referral: Transfer directly to the paediatric emergency department or contact the on-call paediatric orthopaedic registrar for immediate assessment. A routine outpatient referral or deferred community X-ray is not appropriate — this is an orthopaedic emergency.
- ●Analgesia before transfer: Provide oral paracetamol and/or ibuprofen as a minimum. Severe pain in an unstable SUFE may require stronger analgesia; advise the receiving team accordingly.
- ●Imaging in hospital: AP pelvis X-ray is the minimum required view. The frog-leg lateral view provides better visualisation of posterior slippage but is contraindicated in suspected unstable SUFE — forced abduction risks completing the displacement and severing the retinacular vessels. Request a true lateral (cross-table lateral) instead. Communicate this clearly in the referral.
- ●Surgical fixation: Definitive treatment is in situ fixation with a single cannulated screw across the physis to arrest further slippage. This is performed as an urgent procedure.
Contralateral Hip
- ●SUFE carries a 20–40% risk of bilateral involvement, with the contralateral slip often presenting weeks to months later.
- ●The right hip must be assessed radiologically at the receiving unit even if currently asymptomatic.
- ●Families should be counselled that any subsequent groin, thigh, or knee pain on the opposite side requires prompt reassessment.
Referral Criteria
- ●Any child with a clinical suspicion of SUFE — even if still able to partially weight bear — requires same-day orthopaedic review. Do not wait for community imaging.
- ●Inability to weight bear, as in this case, mandates immediate emergency department transfer with strict non-weight-bearing precautions in place from the moment of diagnosis.
Longer-Term Management: Obesity and Paediatric Weight Management
- ●Obesity is the primary modifiable risk factor for SUFE and must be addressed constructively once the acute phase has resolved.
- ●Per NHS England guidance, referral to a Tier 2 or Tier 3 paediatric weight management programme is appropriate for children with a BMI at or above the 91st centile with an obesity-related comorbidity (which SUFE constitutes).
- ●Tier 2 services offer structured lifestyle intervention (diet, physical activity, behavioural support) delivered in the community. Tier 3 services provide multidisciplinary specialist input for complex or severe cases.
- ●Weight management should be framed as a positive, supported pathway — not a punitive response to an injury — particularly in an adolescent already experiencing significant body image distress.
Safeguarding and Psychosocial Management
- ●Disclosure of ongoing severe bullying — including physical intimidation and daily verbal abuse — constitutes a child welfare concern that requires a proactive response, not just acknowledgement.
- ●Appropriate responses include: written communication to the head of year or designated safeguarding lead at the school (with Liam's knowledge and, where appropriate, consent), referral to the school nursing service, and consideration of CAMHS or a GP-based wellbeing referral given the evident body image distress and the risk of psychological harm from prolonged bullying.
- ●The GP should explore with Liam what he is comfortable having shared with his mother, and should not relay confidential disclosures without his agreement — while being clear about the limits of confidentiality if there is a risk of significant harm.
- ●Adolescent confidentiality is governed by Gillick competence: a 13-year-old may be Gillick competent and entitled to have information shared or withheld at his discretion, subject to a risk assessment. In this case, there is no immediate risk to life that would override this, but the welfare concern from bullying should be documented and a plan agreed.
Future Exercise and Physiotherapy
- ●Following surgical fixation and an appropriate healing period, supervised physiotherapy-guided strength training is achievable and should be actively offered as a goal.
- ●Liam's desire to become physically stronger is a positive health motivation that should be reframed and supported — not dismissed. A referral for structured exercise support, initially through physiotherapy and subsequently through a supervised gym programme, addresses both his physical rehabilitation and his underlying psychosocial goals.
- ●This reframing is clinically important: a teenager who understands that the gym ban is temporary and that there is a pathway back to exercise is far more likely to comply with non-weight-bearing instructions and engage with weight management than one who is simply told to stop.
Safety Netting
- ●Before leaving the surgery, both Liam and Karen must understand: Liam must not place any weight on the left leg until reviewed by the orthopaedic team — this means no walking, including to the car or toilet.
- ●If pain significantly worsens, the limb changes colour or temperature, or Liam becomes systemically unwell before reaching hospital, Karen should call 999.
- ●Following surgical fixation, any new pain in the right hip, groin, or thigh must be reported promptly — do not assume it is post-operative or musculoskeletal.
- ●At the post-acute follow-up appointment in primary care, confirm: orthopaedic plan for the contralateral hip, referral to paediatric weight management, and welfare follow-up regarding the bullying.
Common Candidate Mistakes in This Case
- ●Accepting the knee as the diagnosis: The most common and most dangerous error — examining only the knee, finding no gross abnormality, and diagnosing a soft tissue strain. Any overweight adolescent with knee pain must have their hip examined.
- ●Missing the mechanism: Accepting Liam's account of "walking in the park" without gently and specifically probing further. The acute-on-chronic pattern is a pivotal diagnostic clue — candidates who do not establish the true trigger (heavy barbell squats) lose the mechanism entirely.
- ●Failing to engage Liam directly: Conducting the consultation through the mother and never creating space for Liam to speak privately. The bullying disclosure — and the true mechanism — are only available to candidates who address Liam as the patient, not as a bystander.
- ●Permitting weight bearing: Allowing Liam to walk out of the consulting room is a patient safety failure. Non-weight bearing must be instituted before the patient leaves the room.
- ●Offering a deferred X-ray: Booking a community X-ray for later in the week, or a routine outpatient orthopaedic appointment, does not meet the standard for an unstable SUFE. Same-day emergency referral is mandatory.
- ●Banning the gym without addressing the reason: Telling Liam he cannot go to the gym — without acknowledging the bullying that drove him there or offering a future pathway — is both clinically incomplete and therapeutically counterproductive.
Mapped to the RCGP curriculum topic: Musculoskeletal Health.
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