approach to failed total hip replacement revision arthroplasty postgraduate orthopedics

failed total hip replacement revision arthroplasty radiograph loosening

ls -la /tmp/workspace/ 2>/dev/null || mkdir -p /tmp/workspace && echo "created"

mkdir -p /tmp/workspace/failed-thr && cat > /tmp/workspace/failed-thr/generate_pdf.py << 'PYEOF' from reportlab.lib.pagesizes import A4 from reportlab.lib import colors from reportlab.lib.styles import getSampleStyleSheet, ParagraphStyle from reportlab.lib.units import cm, mm from reportlab.platypus import ( SimpleDocTemplate, Paragraph, Spacer, Table, TableStyle, HRFlowable, PageBreak, KeepTogether ) from reportlab.lib.enums import TA_CENTER, TA_LEFT, TA_JUSTIFY from reportlab.platypus import Flowable from reportlab.pdfbase import pdfmetrics from reportlab.pdfbase.ttfonts import TTFont import datetime OUTPUT = "/tmp/workspace/failed-thr/Approach_to_Failed_THR.pdf" # ── Page setup ────────────────────────────────────────────────────────────── doc = SimpleDocTemplate( OUTPUT, pagesize=A4, leftMargin=2*cm, rightMargin=2*cm, topMargin=2.5*cm, bottomMargin=2.5*cm, title="Approach to Failed Total Hip Replacement", author="Orris Medical Education" ) W, H = A4 PW = W - 4*cm # usable page width # ── Colour palette ─────────────────────────────────────────────────────────── DARK_BLUE = colors.HexColor("#1A3A5C") MID_BLUE = colors.HexColor("#2E6DA4") LIGHT_BLUE = colors.HexColor("#D6E8F7") ACCENT = colors.HexColor("#E8522A") # orange-red for key points TABLE_HEADER= colors.HexColor("#2E6DA4") TABLE_ODD = colors.HexColor("#EBF3FA") TABLE_EVEN = colors.white RULE_COLOR = colors.HexColor("#2E6DA4") # ── Styles ─────────────────────────────────────────────────────────────────── styles = getSampleStyleSheet() Title = ParagraphStyle( "Title", parent=styles["Normal"], fontSize=22, textColor=colors.white, leading=28, spaceAfter=4, alignment=TA_CENTER, fontName="Helvetica-Bold" ) Subtitle = ParagraphStyle( "Subtitle", parent=styles["Normal"], fontSize=11, textColor=colors.HexColor("#B0CDE8"), leading=16, spaceAfter=0, alignment=TA_CENTER, fontName="Helvetica-Oblique" ) H1 = ParagraphStyle( "H1", parent=styles["Normal"], fontSize=14, textColor=colors.white, leading=18, spaceBefore=14, spaceAfter=4, fontName="Helvetica-Bold", leftIndent=0 ) H2 = ParagraphStyle( "H2", parent=styles["Normal"], fontSize=11.5, textColor=DARK_BLUE, leading=16, spaceBefore=10, spaceAfter=3, fontName="Helvetica-Bold" ) H3 = ParagraphStyle( "H3", parent=styles["Normal"], fontSize=10.5, textColor=MID_BLUE, leading=15, spaceBefore=7, spaceAfter=2, fontName="Helvetica-Bold" ) Body = ParagraphStyle( "Body", parent=styles["Normal"], fontSize=9.5, textColor=colors.HexColor("#222222"), leading=14, spaceAfter=4, alignment=TA_JUSTIFY, fontName="Helvetica" ) Bullet = ParagraphStyle( "Bullet", parent=Body, leftIndent=14, bulletIndent=4, spaceAfter=2.5 ) SubBullet = ParagraphStyle( "SubBullet", parent=Body, leftIndent=28, bulletIndent=18, spaceAfter=2 ) KeyPoint = ParagraphStyle( "KeyPoint", parent=Body, fontSize=9.5, textColor=DARK_BLUE, leading=14, leftIndent=10, rightIndent=10, spaceAfter=4, backColor=LIGHT_BLUE, borderPad=5, borderColor=MID_BLUE, borderWidth=0 ) CodeStyle = ParagraphStyle( "Code", parent=styles["Normal"], fontSize=8.5, textColor=colors.HexColor("#333333"), leading=13, fontName="Courier", leftIndent=10, spaceAfter=3 ) RefStyle = ParagraphStyle( "Ref", parent=Body, fontSize=8.5, textColor=colors.HexColor("#555555"), leading=13, leftIndent=10 ) # ── Helper: coloured section-header banner ──────────────────────────────────── def section_banner(text, color=DARK_BLUE): data = [[Paragraph(text, H1)]] t = Table(data, colWidths=[PW]) t.setStyle(TableStyle([ ("BACKGROUND", (0,0), (-1,-1), color), ("LEFTPADDING", (0,0), (-1,-1), 8), ("RIGHTPADDING", (0,0), (-1,-1), 8), ("TOPPADDING", (0,0), (-1,-1), 5), ("BOTTOMPADDING",(0,0), (-1,-1), 5), ("ROUNDEDCORNERS", [4]), ])) return t def sub_banner(text): return section_banner(text, color=MID_BLUE) def kp(text): """Key point box.""" return Table( [[Paragraph(f"<b>Key Point:</b> {text}", Body)]], colWidths=[PW], style=TableStyle([ ("BACKGROUND", (0,0), (-1,-1), LIGHT_BLUE), ("LEFTPADDING", (0,0), (-1,-1), 10), ("RIGHTPADDING", (0,0), (-1,-1), 10), ("TOPPADDING", (0,0), (-1,-1), 5), ("BOTTOMPADDING",(0,0), (-1,-1), 5), ("LINEAFTER", (0,0), (0,-1), 3, MID_BLUE), ]) ) def hr(): return HRFlowable(width="100%", thickness=0.5, color=RULE_COLOR, spaceAfter=4, spaceBefore=4) def sp(h=4): return Spacer(1, h) # ── Standard table builder ──────────────────────────────────────────────────── def make_table(headers, rows, col_widths=None): if col_widths is None: n = len(headers) col_widths = [PW / n] * n data = [[Paragraph(f"<b>{h}</b>", ParagraphStyle( "TH", parent=Body, textColor=colors.white, fontSize=9, fontName="Helvetica-Bold" )) for h in headers]] for i, row in enumerate(rows): data.append([Paragraph(str(c), ParagraphStyle( "TD", parent=Body, fontSize=9, backColor=TABLE_ODD if i % 2 == 0 else TABLE_EVEN )) for c in row]) style = TableStyle([ ("BACKGROUND", (0,0), (-1,0), TABLE_HEADER), ("ROWBACKGROUNDS", (0,1), (-1,-1), [TABLE_ODD, TABLE_EVEN]), ("GRID", (0,0), (-1,-1), 0.4, colors.HexColor("#BBBBBB")), ("TOPPADDING", (0,0), (-1,-1), 4), ("BOTTOMPADDING",(0,0),(-1,-1), 4), ("LEFTPADDING",(0,0),(-1,-1), 5), ("RIGHTPADDING",(0,0),(-1,-1), 5), ("VALIGN", (0,0), (-1,-1), "TOP"), ]) t = Table(data, colWidths=col_widths, repeatRows=1) t.setStyle(style) return t # ── Cover-page builder ──────────────────────────────────────────────────────── def cover_page(): elems = [] # Full-width dark blue header bar cover_data = [[ Paragraph("APPROACH TO FAILED<br/>TOTAL HIP REPLACEMENT", Title), Paragraph("Postgraduate Orthopaedics Long Answer", Subtitle), ]] cover = Table( [[Paragraph("APPROACH TO FAILED TOTAL HIP REPLACEMENT (THR)", Title)], [Paragraph("Postgraduate Orthopaedics · Long Answer", Subtitle)], [Paragraph(f"Prepared by Orris Medical Education · {datetime.date.today().strftime('%B %Y')}", Subtitle)]], colWidths=[PW], style=TableStyle([ ("BACKGROUND", (0,0), (-1,-1), DARK_BLUE), ("LEFTPADDING", (0,0),(-1,-1), 20), ("RIGHTPADDING",(0,0),(-1,-1), 20), ("TOPPADDING", (0,0),(-1,-1), 30), ("BOTTOMPADDING",(0,0),(-1,-1), 30), ]) ) elems.append(cover) elems.append(sp(16)) # Intro paragraph elems.append(Paragraph( "Failed total hip replacement (THR) - also called failed total hip arthroplasty (THA) - refers to a " "prosthetic hip joint that no longer achieves its intended goals of pain relief, function, and stability. " "It is a growing clinical problem given the rising number of primary THRs performed globally and the " "longer survival of younger, more active patients. A systematic approach is essential because the <b>cause " "of failure determines the management</b>.", Body )) elems.append(sp(8)) elems.append(PageBreak()) return elems # ══════════════════════════════════════════════════════════════════════════════ # BUILD DOCUMENT # ══════════════════════════════════════════════════════════════════════════════ story = [] story += cover_page() # ─── 1. CAUSES ─────────────────────────────────────────────────────────────── story.append(section_banner("1. CAUSES OF FAILURE (AETIOLOGY)")) story.append(sp(6)) story.append(make_table( ["Cause of Failure", "Approximate Frequency"], [ ["Aseptic loosening / osteolysis", "23–45%"], ["Instability / dislocation", "~22%"], ["Periprosthetic joint infection (PJI)", "~22%"], ["Periprosthetic fracture", "10–15%"], ["Implant fracture / mechanical failure", "~5%"], ["Bearing surface failure (wear, corrosion, trunnionosis)", "~5%"], ["Soft tissue impingement, nerve injury, LLD", "Rare"], ], col_widths=[PW*0.70, PW*0.30] )) story.append(sp(8)) # ─── 2. HISTORY ────────────────────────────────────────────────────────────── story.append(section_banner("2. HISTORY AND CLINICAL EVALUATION")) story.append(sp(6)) story.append(Paragraph("A. Symptom Analysis", H2)) story.append(Paragraph("The character of pain is the most important diagnostic clue:", Body)) story.append(make_table( ["Pain Character", "Most Likely Diagnosis"], [ ["Start-up pain (improves after first few steps)", "Aseptic loosening (most characteristic)"], ["Constant rest pain / night pain", "Periprosthetic joint infection"], ["Pain on weight-bearing that never settles", "Loosening or periprosthetic fracture"], ["Sudden giving way / frank dislocation", "Instability"], ["Groin pain", "Acetabular loosening, iliopsoas impingement, anterior impingement"], ["Thigh pain", "Femoral stem loosening (especially cemented)"], ], col_widths=[PW*0.50, PW*0.50] )) story.append(sp(6)) story.append(Paragraph("B. Timing of Onset", H2)) story.append(make_table( ["Time from Surgery", "Likely Cause"], [ ["< 3 months (early)", "Acute PJI, wound complication, dislocation, periprosthetic fracture"], ["3–24 months (intermediate)", "Haematogenous PJI, early loosening, instability"], ["> 2 years (late)", "Aseptic loosening, wear/osteolysis, late PJI, periprosthetic fracture"], ], col_widths=[PW*0.30, PW*0.70] )) story.append(sp(6)) story.append(Paragraph("C. Relevant History to Document", H2)) bullets_hist = [ "Original indication for THR (OA, AVN, fracture, dysplasia)", "Type of implant, surgical approach, fixation method used", "Previous complications (dislocation, wound infection, re-operations)", "Comorbidities: diabetes, immunosuppression, obesity, rheumatoid arthritis", "Medications: steroids, anticoagulants, bisphosphonates", "Social history: activity level, smoking, BMI", ] for b in bullets_hist: story.append(Paragraph(f"\u2022 {b}", Bullet)) story.append(sp(8)) # ─── 3. EXAMINATION ────────────────────────────────────────────────────────── story.append(section_banner("3. PHYSICAL EXAMINATION")) story.append(sp(6)) exam_items = [ ("<b>Gait:</b>", "Trendelenburg gait (abductor weakness), antalgic gait"), ("<b>Leg length discrepancy:</b>", "Clinical (apparent vs. true) and radiological measurement"), ("<b>Range of motion:</b>", "Restricted or painful ROM; note direction of pain provocation"), ("<b>Trendelenburg sign:</b>", "Indicates abductor insufficiency"), ("<b>FADIR test:</b>", "Flexion-adduction-internal rotation – anterior impingement"), ("<b>Neurovascular exam:</b>", "Sciatic (dorsiflexion, sensation) and femoral nerve function"), ("<b>Wound:</b>", "Sinuses, erythema, warmth, discharge – strongly suggestive of PJI"), ("<b>Limb alignment:</b>", "Offset restoration, mechanical axis"), ] for label, val in exam_items: story.append(Paragraph(f"\u2022 {label} {val}", Bullet)) story.append(sp(8)) # ─── 4. INVESTIGATIONS ─────────────────────────────────────────────────────── story.append(section_banner("4. INVESTIGATIONS")) story.append(sp(6)) story.append(Paragraph("A. Radiological Investigations", H2)) story.append(Paragraph("Plain X-rays (AP Pelvis + Lateral Hip + Full-length Femur)", H3)) xray_bullets = [ "<b>Component migration</b> – compare with immediate post-op films", "<b>Radiolucent lines</b> at cement-bone / implant-bone interface (Gruen zones for femur, DeLee & Charnley zones for acetabulum)", "<b>Continuous radiolucent line ≥ 2 mm</b> in all zones = definite loosening", "<b>Osteolysis</b> – expansile radiolucent lesions around implant", "<b>Subsidence</b> – vertical migration of femoral stem", "<b>Polyethylene wear</b> – eccentric position of femoral head within cup", "<b>Periprosthetic fracture</b>", "<b>Component orientation</b> – cup inclination (ideal 40–45°) and anteversion (15–20°)", ] for b in xray_bullets: story.append(Paragraph(f"\u2022 {b}", Bullet)) story.append(sp(4)) story.append(Paragraph("Advanced Imaging", H3)) story.append(make_table( ["Modality", "Indication", "Key Finding"], [ ["CT scan", "Bone loss assessment, component version", "Paprosky classification, pelvic discontinuity"], ["MARS MRI", "MoM bearing failure; suspected pseudotumor", "ALTR, pseudotumor, soft tissue planes"], ["Bone scan (Tc-99m)", "Loosening vs. infection screening", "Increased uptake; low specificity after 2 yrs"], ["Labelled leucocyte + bone-marrow scan", "Suspected PJI (higher specificity)", "Mismatch = infection"], ], col_widths=[PW*0.18, PW*0.42, PW*0.40] )) story.append(sp(8)) story.append(Paragraph("B. Laboratory Investigations", H2)) story.append(make_table( ["Test", "Significance / Threshold"], [ ["ESR", "Screening for PJI; threshold > 30 mm/hr (MSIS criteria)"], ["CRP", "Most sensitive routine marker; > 10 mg/L threshold for PJI"], ["IL-6", "High sensitivity; > 12 pg/mL suggestive of PJI"], ["D-dimer", "Emerging marker; non-inferior to CRP for PJI diagnosis"], ["Serum Co & Cr", "If metal-on-metal bearing or trunnionosis suspected"], ["Serum WBC", "Usually normal in PJI – low sensitivity"], ], col_widths=[PW*0.30, PW*0.70] )) story.append(sp(6)) story.append(Paragraph("C. Joint Aspiration (KEY Investigation)", H2)) story.append(kp("Indicated whenever PJI is suspected. Must be done before antibiotics. Stop antibiotics ≥ 2 weeks before aspiration if possible.")) story.append(sp(4)) story.append(make_table( ["Aspirate Parameter", "Chronic PJI Threshold", "Acute PJI Threshold"], [ ["Synovial WBC count", "≥ 3,000 cells/mm³", "≥ 10,000 cells/mm³"], ["Neutrophil % (PMN)", "≥ 80%", "≥ 90%"], ["Alpha-defensin", "Positive (>1 signal-to-noise)", "Positive"], ["Leukocyte esterase (strip)", "++ (colorimetric)", "++"], ["Culture & sensitivity", "3+ samples; hold 14 days", "Same"], ], col_widths=[PW*0.38, PW*0.31, PW*0.31] )) story.append(sp(4)) story.append(Paragraph( "<b>2018 ICM / MSIS Criteria for PJI:</b> Score-based system. " "<b>Major criteria (either alone = PJI):</b> (1) Sinus tract communicating with implant; " "(2) Two positive cultures of same organism. " "<b>Minor criteria (scored):</b> Elevated ESR/CRP, elevated synovial WBC, positive alpha-defensin, " "elevated synovial PMN%, positive histology, single positive culture.", Body )) story.append(sp(10)) # ─── 5. BONE LOSS CLASSIFICATION ───────────────────────────────────────────── story.append(section_banner("5. CLASSIFICATION OF BONE LOSS")) story.append(sp(6)) story.append(Paragraph("A. Acetabular Bone Loss – Paprosky Classification", H2)) story.append(make_table( ["Type", "Description", "Management"], [ ["I", "Minimal bone loss; supportive rim intact", "Hemispheric cup"], ["IIA", "Superior medial defect; < 2 cm superior migration", "Hemispheric cup ± screws"], ["IIB", "> 50% cup uncovered; ≤ 2 cm migration", "Hemispheric cup + screws"], ["IIC", "Medial wall defect", "Hemispheric cup"], ["IIIA", "Severe: 2–3 cm superior migration; 40–60% host bone", "Cup + augments, tantalum metal"], ["IIIB", "> 3 cm migration; severe destruction (< 40% bone)", "Cup-cage, triflange, custom implant"], ], col_widths=[PW*0.10, PW*0.55, PW*0.35] )) story.append(sp(4)) story.append(kp("Pelvic discontinuity – fracture separating superior and inferior pelvis – is addressed with cup-cage constructs or custom triflange implants.")) story.append(sp(6)) story.append(Paragraph("B. Femoral Bone Loss – Paprosky Classification", H2)) story.append(make_table( ["Type", "Proximal Bone", "Diaphysis", "Preferred Implant"], [ ["I", "Minimal loss", "Intact", "Any primary or revision stem"], ["II", "Extensive proximal", "Intact", "Modular revision stem"], ["IIIA", "Severe; ≥ 4 cm bone", "Intact", "Extensively coated / tapered fluted titanium"], ["IIIB", "Severe; < 4 cm bone", "Compromised", "Tapered fluted modular titanium stem (mainstay)"], ["IV", "Minimal diaphyseal", "Compromised", "Proximal femoral replacement (tumour prosthesis)"], ], col_widths=[PW*0.10, PW*0.25, PW*0.22, PW*0.43] )) story.append(sp(4)) story.append(kp("Most femoral revisions use cementless tapered fluted modular titanium stems. Cemented femoral revision is AVOIDED in revision settings due to high early mechanical failure.")) story.append(sp(6)) story.append(Paragraph("C. Vancouver Classification – Periprosthetic Fracture around THA", H2)) story.append(make_table( ["Type", "Location", "Stem Stability", "Management"], [ ["AG", "Greater trochanter", "Stable", "ORIF vs. conservative"], ["AL", "Lesser trochanter", "Stable", "Conservative"], ["B1", "Around stem", "Well-fixed", "ORIF with locking plates + cables"], ["B2", "Around stem", "Loose stem", "Revision long-stem (bypass by 2 cortical diameters)"], ["B3", "Around stem", "Loose + bone loss", "Revision ± allograft / proximal femoral prosthesis"], ["C", "Below stem tip", "Stable", "Standard ORIF"], ], col_widths=[PW*0.08, PW*0.22, PW*0.18, PW*0.52] )) story.append(sp(10)) story.append(PageBreak()) # ─── 6. MANAGEMENT ─────────────────────────────────────────────────────────── story.append(section_banner("6. MANAGEMENT APPROACH")) story.append(sp(6)) story.append(Paragraph("General Principles", H2)) principles = [ "<b>Treat the cause</b> – identify the specific failure mode before operating", "<b>Exclude infection first</b> – every revision must rule out PJI before aseptic revision", "<b>Pre-operative planning</b> – templating, bone graft requirements, implant selection", "<b>Preserve bone stock</b> – impaction allografting preferred in younger patients", "<b>Restore biomechanics</b> – offset, leg length, version, centre of rotation", ] for p in principles: story.append(Paragraph(f"\u2022 {p}", Bullet)) story.append(sp(6)) # 6A Aseptic loosening story.append(sub_banner(" 6A. Aseptic Loosening / Osteolysis")) story.append(sp(4)) story.append(Paragraph("Well-fixed components with contained osteolysis:", H3)) story.append(Paragraph("\u2022 Debridement + bone grafting + liner exchange (if well-positioned)", Bullet)) story.append(Paragraph("Loose components – Revision arthroplasty:", H3)) story.append(Paragraph("\u2022 <b>Acetabular revision:</b> Hemispheric porous cup with multiple screws (majority of cases); modular metal augments for severe bone loss; cup-cage / triflange for Paprosky IIIB / pelvic discontinuity", Bullet)) story.append(Paragraph("\u2022 <b>Femoral revision:</b> Cementless tapered fluted modular titanium stem (preferred); extensively porous-coated cylindrical stem; impaction allografting (younger patients – preserves bone stock)", Bullet)) story.append(sp(6)) # 6B PJI story.append(sub_banner(" 6B. Periprosthetic Joint Infection (PJI)")) story.append(sp(4)) story.append(Paragraph("Early Acute PJI (< 4–6 weeks from index surgery or < 3 weeks of symptoms):", H3)) story.append(Paragraph( "<b>DAIR</b> (Debridement, Antibiotics, Implant Retention): Irrigation and debridement + " "exchange of modular components (head and liner) + 3–6 months targeted antibiotics. " "Success rate: 60–80% if done early with susceptible organism.", Body )) story.append(sp(4)) story.append(Paragraph("Chronic / Late PJI:", H3)) story.append(make_table( ["Approach", "Description", "Success Rate"], [ ["Two-stage exchange\n(GOLD STANDARD)", "Stage 1: Explant all components + debridement + antibiotic-loaded cement spacer (static or articulating)\n" "→ 6–8 weeks IV antibiotics (culture-directed)\n" "→ Check ESR, CRP, aspiration\n" "Stage 2: Reimplantation when markers normalise", "~85–90%"], ["One-stage exchange", "Selected cases: sensitive organism, good bone stock, healthy patient. Lower morbidity.", "~75–85%"], ["Suppressive antibiotics", "Palliative. For medically unfit patients or low-virulence organism.", "Not curative"], ["Girdlestone procedure\n(excision arthroplasty)", "Last resort when repeated revisions fail or patient unfit for reimplantation. " "Gives pain relief at cost of function (shortening, limp, walking aid).", "Salvage only"], ], col_widths=[PW*0.22, PW*0.55, PW*0.23] )) story.append(sp(6)) # 6C Instability story.append(sub_banner(" 6C. Instability / Dislocation")) story.append(sp(4)) story.append(Paragraph("\u2022 <b>Immediate:</b> Closed reduction under conscious sedation (urgent)", Bullet)) story.append(Paragraph("\u2022 Assess cause: component malposition, soft tissue laxity, impingement, inadequate offset", Bullet)) story.append(Paragraph("Conservative (first dislocation, no malposition):", H3)) story.append(Paragraph("\u2022 Hip brace, activity modification, rehabilitation", Bullet)) story.append(Paragraph("Surgical Management:", H3)) story.append(make_table( ["Scenario", "Intervention"], [ ["Malpositioned components", "Component revision to safe zone"], ["Well-positioned; recurrent dislocation", "Dual-mobility cup (most popular – increases jump distance)"], ["Severe abductor deficiency / cognitive impairment", "Constrained liner"], ["Abductor deficiency + malposition", "Trochanteric advancement + component repositioning"], ["Large head option", "36–40 mm femoral head (if acetabular geometry permits)"], ], col_widths=[PW*0.48, PW*0.52] )) story.append(sp(6)) # 6D Periprosthetic fracture story.append(sub_banner(" 6D. Periprosthetic Fracture (Vancouver Classification)")) story.append(sp(4)) peripro_items = [ ("<b>Vancouver B1:</b>", "ORIF with lateral locking plates + cables (stem stable, well-fixed)"), ("<b>Vancouver B2:</b>", "Long-stem revision arthroplasty bypassing fracture by ≥ 2 cortical diameters"), ("<b>Vancouver B3:</b>", "Long-stem revision + impaction allografting / strut grafts / proximal femoral replacement"), ("<b>Vancouver C:</b>", "Standard ORIF distal to stem (stem stable, not involved)"), ] for label, val in peripro_items: story.append(Paragraph(f"\u2022 {label} {val}", Bullet)) story.append(sp(6)) # 6E Bearing failure story.append(sub_banner(" 6E. Bearing Surface Failure / Trunnionosis")) story.append(sp(4)) bearing_items = [ ("<b>Trunnionosis</b> (fretting corrosion at modular junction):", "Replace metal head with ceramic head + titanium sleeve adaptor; assess soft tissues for pseudotumor/ALTR"), ("<b>Metal-on-metal (MoM) failure / ALVAL</b>:", "Revise when serum cobalt > 7 ppb and/or pseudotumor on MARS MRI; remove MoM bearing; pseudotumor excision"), ("<b>Ceramic fracture:</b>", "Remove ALL ceramic fragments (use MARS MRI); replace with new ceramic on ceramic or ceramic on HCLPE"), ("<b>Polyethylene wear:</b>", "Head and liner exchange if components well-fixed and positioned; address acetabular position if malpositioned"), ] for label, val in bearing_items: story.append(Paragraph(f"\u2022 {label} {val}", Bullet)) story.append(sp(10)) # ─── 7. SURGICAL APPROACH ──────────────────────────────────────────────────── story.append(section_banner("7. SURGICAL APPROACH FOR REVISION THR")) story.append(sp(6)) story.append(Paragraph("Choice of Surgical Approach", H2)) story.append(make_table( ["Approach", "Features", "Best For"], [ ["Posterior", "Most common; extensile; good acetabular and femoral access", "Most revision cases"], ["Transtrochanteric (standard / slide)", "Best exposure; trochanteric slide preserves abductor; risk of trochanteric nonunion ~10–15%", "Difficult revisions requiring wide exposure"], ["Extended Trochanteric Osteotomy (ETO)", "Gold standard for removing well-fixed cementless stems or cement mantles; splits proximal femur reflecting GT with anterior cortex", "Well-fixed ingrown stems; long cement columns"], ], col_widths=[PW*0.22, PW*0.48, PW*0.30] )) story.append(sp(6)) story.append(Paragraph("Component Removal (Campbell's 15th Ed)", H2)) story.append(Paragraph("<b>Cemented femoral component:</b>", H3)) story.append(Paragraph("\u2022 Grossly loose: manual removal", Bullet)) story.append(Paragraph("\u2022 Fixed: ultrasonic cement removal tools, osteotomes, reverse hooks; ETO provides best access to cement column", Bullet)) story.append(Paragraph("<b>Cementless femoral component:</b>", H3)) story.append(Paragraph("\u2022 Ingrown stems require ETO; custom extraction devices (Moreland, endoscope-assisted)", Bullet)) story.append(Paragraph("<b>Acetabular component:</b>", H3)) story.append(Paragraph("\u2022 Curved osteotomes at cup-bone interface; Cup-ex system for cementless cups; minimise bone loss during extraction", Bullet)) story.append(sp(10)) # ─── 8. PREOPERATIVE PLANNING ───────────────────────────────────────────────── story.append(section_banner("8. PREOPERATIVE PLANNING")) story.append(sp(6)) preop = [ "<b>Templating</b> on calibrated digital radiographs", "<b>Implant records</b> from index surgery (type, size, manufacturer)", "<b>CT scan</b> for bone loss quantification (Paprosky type)", "<b>Blood bank</b> crossmatch – revision THR has high blood loss (transfusion rates 30–50%)", "<b>Infectious disease review</b> if PJI suspected or cannot be excluded", "<b>Bone graft availability</b> – allograft bank, demineralised bone matrix", "<b>Implant inventory:</b> Full range of modular revision femoral stems and acetabular augments", "<b>Anaesthetic assessment:</b> Regional (spinal/epidural preferred – reduces blood loss) vs. general", "<b>VTE prophylaxis plan</b> and cell salvage (intraoperative)", ] for p in preop: story.append(Paragraph(f"\u2022 {p}", Bullet)) story.append(sp(10)) # ─── 9. COMPLICATIONS ───────────────────────────────────────────────────────── story.append(section_banner("9. COMPLICATIONS OF REVISION THR")) story.append(sp(6)) story.append(make_table( ["Complication", "Approximate Rate"], [ ["Dislocation (most common post-revision)", "5–15%"], ["Periprosthetic fracture", "3–10%"], ["Nerve injury (sciatic most common)", "1–3%"], ["Wound complications / superficial infection", "3–5%"], ["DVT / PE", "1–3%"], ["Aseptic re-loosening", "5–15% at 10 years"], ["Leg length discrepancy", "10–20%"], ["Re-revision (markedly higher in obese patients and age < 55 years)", "Higher risk groups"], ], col_widths=[PW*0.70, PW*0.30] )) story.append(sp(10)) # ─── 10. OUTCOMES ───────────────────────────────────────────────────────────── story.append(section_banner("10. OUTCOMES")) story.append(sp(6)) story.append(Paragraph( "Revision THR has significantly worse outcomes than primary THR. Key outcome data:", Body )) story.append(make_table( ["Revision Indication", "10-Year Survival (no re-revision)"], [ ["Aseptic loosening", "~70–80%"], ["PJI two-stage exchange", "~85–90%"], ["Instability", "~70–75%"], ["Periprosthetic fracture", "~65–75%"], ], col_widths=[PW*0.55, PW*0.45] )) story.append(sp(6)) story.append(Paragraph("<b>Predictors of poor outcome:</b>", H3)) poor_pred = [ "Infection (vs. aseptic cause)", "Severe bone loss (Paprosky IIIB acetabular or femoral IV)", "Young age (< 55 years) – higher activity demands", "Obesity (BMI > 30) – markedly higher re-revision rates (p < 0.01)", "Multiple prior revisions", "Abductor deficiency", ] for p in poor_pred: story.append(Paragraph(f"\u2022 {p}", Bullet)) story.append(sp(10)) # ─── 11. ALGORITHM ───────────────────────────────────────────────────────────── story.append(section_banner("11. DIAGNOSTIC & MANAGEMENT ALGORITHM")) story.append(sp(6)) algo_lines = [ ("FAILED THR", 0), ("│", 0), ("├── STEP 1: EXCLUDE INFECTION (always first)", 0), ("│ ESR, CRP → Elevated? → Joint aspiration", 1), ("│ Aspirate: WBC, neutrophil %, alpha-defensin, culture", 1), ("│ ├── PJI CONFIRMED → Early: DAIR | Chronic: Two-stage exchange", 1), ("│ └── NOT INFECTED → proceed to Step 2", 1), ("│", 0), ("├── STEP 2: RADIOLOGICAL ASSESSMENT", 0), ("│ Plain X-ray → Loosening? Migration? Fracture? Malposition? Wear?", 1), ("│ CT → Bone loss (Paprosky type), Component version", 1), ("│ MARS MRI → MoM failure, pseudotumor, soft tissue", 1), ("│", 0), ("├── STEP 3: IDENTIFY CAUSE & MANAGE", 0), ("│ Aseptic loosening → Revision with cementless implants ± bone graft", 1), ("│ Instability → Dual-mobility cup / component revision", 1), ("│ PPF → Vancouver classification → ORIF or revision stem", 1), ("│ Bearing failure → Head/liner/trunnion revision", 1), ("│ LLD / impingement → Component repositioning", 1), ("│", 0), ("└── STEP 4: PLAN REVISION SURGERY", 0), (" Templating, bone graft, ETO if needed, implant inventory", 1), ] algo_data = [[Paragraph(line, ParagraphStyle( "Algo", parent=styles["Normal"], fontName="Courier", fontSize=8.5, leading=13, textColor=colors.HexColor("#1A3A5C"), leftIndent=indent*12 ))] for line, indent in algo_lines] algo_table = Table(algo_data, colWidths=[PW]) algo_table.setStyle(TableStyle([ ("BACKGROUND", (0,0), (-1,-1), colors.HexColor("#EBF3FA")), ("TOPPADDING", (0,0), (-1,-1), 2), ("BOTTOMPADDING", (0,0), (-1,-1), 2), ("LEFTPADDING", (0,0), (-1,-1), 10), ("RIGHTPADDING", (0,0), (-1,-1), 10), ("BOX", (0,0), (-1,-1), 1, MID_BLUE), ])) story.append(algo_table) story.append(sp(12)) # ─── REFERENCES ─────────────────────────────────────────────────────────────── story.append(section_banner("REFERENCES")) story.append(sp(6)) refs = [ "Miller's Review of Orthopaedics, 9th Edition – Section 6: Revision Total Hip Arthroplasty", "Campbell's Operative Orthopaedics, 15th Ed 2026 – Revision THA; Transtrochanteric Approach; Loosening/Osteolysis", "Schwartz's Principles of Surgery, 11th Ed – Complications in Joint Arthroplasty; Osteolysis and Aseptic Loosening", "Rockwood and Green's Fractures in Adults, 10th Ed 2025 – Revision Arthroplasty for Periprosthetic Fractures", "Systematic review of causes of revision THA failure. J Orthop. 2019; PMC6512562", "Diagnosis of the failed total hip replacement. EFORT Open Rev. 2020; PMC6985031", "2018 ICM / MSIS Criteria for Periprosthetic Joint Infection", ] for i, r in enumerate(refs, 1): story.append(Paragraph(f"{i}. {r}", RefStyle)) story.append(sp(6)) # ─── Footer note ─────────────────────────────────────────────────────────────── story.append(hr()) story.append(Paragraph( f"Generated by Orris Medical Education · {datetime.date.today().strftime('%d %B %Y')} · " "For postgraduate orthopaedics examination preparation", ParagraphStyle("Footer", parent=Body, fontSize=8, textColor=colors.grey, alignment=TA_CENTER) )) # ── Build ───────────────────────────────────────────────────────────────────── doc.build(story) print(f"PDF created: {OUTPUT}") PYEOF echo "Script written"

cd /tmp/workspace/failed-thr && python generate_pdf.py

ls -lh /tmp/workspace/failed-thr/Approach_to_Failed_THR.pdf