Joint Replacement & Spine | Dr. Chang Xiao (Orthopedics) | CMCS Shanghai

About Dr. Chang Xiao

Dr. Chang Xiao is a senior orthopaedic surgeon and Director of the Joint Reconstruction and Sports Medicine Unit at Ruijin Hospital, Shanghai Jiao Tong University School of Medicine — one of China's leading academic medical centres for minimally invasive joint replacement, spinal disorders, and sports medicine. He is a pioneer of the direct anterior approach (DAA) to total hip replacement in China, and his centre is a national reference site for the integration of sports medicine techniques — including arthroscopic labral repair and anchor-based reconstruction — into joint replacement surgery. Dr. Chang's practice is defined by the philosophy that joint replacement is not simply component implantation but functional reconstruction: restoring the biomechanical environment of the hip, preserving soft tissue integrity, and enabling patients to return to the activities that define their quality of life. He has extensive experience treating international patients with complex hip pathology including developmental dysplasia of the hip (DDH), femoroacetabular impingement (FAI), and combined hip-spine syndrome, and his enhanced recovery after surgery (ERAS) protocols consistently achieve full weight-bearing ambulation within 24 hours of operation. Dr. Chang has published in leading orthopaedic journals and lectures internationally on minimally invasive hip reconstruction and the biomechanical relationship between hip dysplasia, pelvic tilt, and lumbar degeneration.

Case Overview

Ms. Margaret Lawson, a 54-year-old Australian former dance instructor, presented with a five-year history of right hip pain and clicking, acutely worsening over three months with right lower limb radicular pain and intermittent claudication limiting her walking distance to 500 metres. She had carried a known diagnosis of developmental dysplasia of the hip (DDH) since childhood without definitive treatment. Pelvic radiography confirmed Crowe Type II right DDH with a centre-edge angle of 15°, severe joint space narrowing, and osteophyte formation. Lumbar MRI demonstrated a large L4–5 disc herniation with spinal canal stenosis and nerve root compression. Hip MR arthrography identified an anterosuperior acetabular labral tear and partial round ligament rupture. Dr. Chang Xiao designed a single-stage minimally invasive strategy: direct anterior approach (DAA) total hip replacement using a ceramic-on-ceramic bearing with a high-offset femoral stem, combined with intraoperative arthroscopic labral débridement and anchor-based labral repair to restore the acetabular seal — performed through the same DAA incision without muscle division. The lumbar stenosis was managed conservatively post-operatively, with structured spinal rehabilitation, on the basis that correction of hip dysplasia and restoration of pelvic alignment would substantially reduce lumbar compensatory stress. At six-month follow-up, Harris Hip Score was 95, Oswestry Disability Index had fallen by 80%, and Ms. Lawson had returned to daily 10,000-step walking and low-intensity dance exercise.

Patient Background

• Name / Nationality: Ms. Margaret Lawson (pseudonym) — Australian
• Age / Sex: 54-year-old female
• Occupation: Former dance instructor; active lifestyle; had ceased all exercise due to pain for 1 year prior to presentation
• Chief Complaint: Right hip pain with clicking for 5 years; worsening with right lower limb radicular pain and intermittent claudication for 3 months
• Hip History: Known developmental dysplasia of the hip (DDH) since childhood — untreated; progressive activity limitation over 5 years with catching and locking sensation
• Lumbar Symptoms: Low back ache; claudication at 500 metres; right lateral thigh numbness
• Physical Examination — Hip: Right FABER test positive; hip flexion limited to 90°; Thomas sign positive
• Physical Examination — Spine: L4–5 spinous process tenderness; right straight leg raise positive at 60°; lower limb power MRC Grade V; mild sensory reduction in right L4–5 dermatomal distribution
• Functional Impact: Unable to participate in dance or sustained walking for 1 year; significant quality-of-life impairment

Imaging and Diagnosis

Pelvic Radiography

• DDH classification: Right Crowe Type II developmental dysplasia of the hip
• Centre-edge (CE) angle: 15° — severely deficient acetabular coverage (normal ≥25°)
• Joint space: Severely narrowed; subchondral sclerosis; marginal osteophyte formation — secondary osteoarthritis established
• Limb length discrepancy: Right limb 1.2 cm shorter than left — contributing to pelvic obliquity and lumbar compensatory scoliosis

Lumbar MRI

• L4–5: Large posterior disc herniation; significant spinal canal stenosis; compression of the dural sac and right L5 nerve root
• L3–4: Mild disc degeneration without significant stenosis
• Surgical implication: Nerve root compression consistent with radicular symptoms; however, pelvic obliquity from DDH identified as a contributing driver of lumbar degeneration — hip correction prioritised

Hip MR Arthrography (MRA)

• Anterosuperior labrum: Full-thickness labral tear at the anterosuperior acetabular rim — consistent with chronic impingement from dysplastic acetabular morphology
• Round ligament: Partial rupture — contributing to hip instability and pain
• Articular cartilage: Full-thickness cartilage loss at the weight-bearing zone — confirming end-stage osteoarthritis

Clinical Diagnosis

• Right DDH (Crowe Type II) with secondary end-stage osteoarthritis
• Right anterosuperior acetabular labral tear — sports medicine injury superimposed on dysplastic morphology
• Partial round ligament rupture
• Lumbar spinal stenosis — L4–5, with right L5 nerve root compression
• Right limb length discrepancy 1.2 cm; pelvic obliquity; compensatory lumbar scoliosis

Clinical Decision Making

Three intersecting problems defined this case: end-stage hip osteoarthritis from DDH requiring total hip replacement; an intra-articular labral tear that, if left unaddressed, would cause persistent post-operative pain and accelerate implant wear; and lumbar spinal stenosis whose severity was partly a consequence of the hip dysplasia itself — through the mechanism of pelvic obliquity and compensatory lumbar loading. The conventional surgical approach — posterior lateral total hip replacement followed by staged spinal surgery — would have required two separate anaesthetics, two recovery periods, and would have left the labral pathology unaddressed. The posterior lateral approach also carries a 2–4% dislocation risk and requires post-operative movement restrictions that are incompatible with an active patient's rehabilitation goals.

Dr. Chang Xiao's integrated strategy: This patient does not have three separate problems. She has one biomechanical problem with three expressions. The DDH is the root cause: it created the acetabular deficiency, which caused the labral tear, which accelerated the cartilage loss, which created the limb length discrepancy, which tilted the pelvis, which overloaded the lumbar spine. If we correct the hip — restore the centre of rotation, equalise limb length, reconstruct the labral seal — we address the root cause. The lumbar stenosis may not need surgery at all once the pelvis is level. DAA gives us the muscle-sparing corridor we need for early rehabilitation. And because we are already inside the joint through the DAA incision, we can address the labral tear arthroscopically in the same sitting. One anaesthetic. One recovery. One operation that solves the biomechanical chain.

Surgical Procedure

Phase 1 — DAA Approach and Acetabular Preparation

Position: Supine on a Hana traction table — enabling intraoperative fluoroscopy and arthroscopic access without repositioning
Approach: Direct anterior approach (DAA) through the Hueter interval — the natural intermuscular plane between tensor fasciae latae (lateral) and sartorius (medial), with no muscle division or tendon detachment of any kind
Fluoroscopic guidance: Real-time C-arm fluoroscopy throughout acetabular reaming and component positioning

The hip capsule was opened anteriorly and the femoral head dislocated anteriorly — without posterior capsule violation and without division of the short external rotators. The femoral head was resected with precise osteotomy, and the acetabulum was reamed sequentially to the planned diameter. AI-assisted pre-operative templating was used to define the target acetabular inclination (42°) and anteversion (18°) — with intraoperative fluoroscopy confirming component position within 2° of the planned angles.

Dr. Chang's operative note: The Hueter interval is the key to everything DAA offers. We are operating between muscles, not through them. No tendon is cut. No muscle is detached. The posterior capsule and the short external rotators — the structures that prevent dislocation — are never touched. When this patient wakes up, she has a new hip and an intact muscular envelope. That is why she can walk the next morning without dislocation precautions. The approach is the rehabilitation.

Phase 2 — Arthroscopic Labral Repair (Intraoperative Sports Medicine Integration)

Following acetabular component implantation and trial reduction, dynamic assessment revealed persistent anterior impingement — confirmed on direct visualisation as fragmented labral tissue at the anterosuperior acetabular rim catching against the femoral neck during flexion and internal rotation.

Utilising the visualisation advantage of the open DAA incision, an arthroscopic probe was introduced into the acetabular recess. Arthroscopic assessment confirmed the MRA findings: a full-thickness anterosuperior labral tear with degenerative fragmentation at the tear margin, and a zone of healthy labral tissue proximal to the tear suitable for anchor-based repair.

Labral débridement: Radiofrequency ablation was used to débride the fragmented, non-viable labral tissue — eliminating the mechanical impingement source.
Labral repair: Two suture anchors were implanted at the anterosuperior acetabular rim. The remaining healthy labral tissue was re-approximated to the acetabular edge using mattress sutures — restoring the labral seal (the negative intra-articular pressure mechanism that contributes to hip joint stability and fluid film lubrication of the articular surface).
Assessment: Following repair, dynamic testing confirmed elimination of impingement and restoration of smooth hip motion through the full arc of flexion, internal rotation, and abduction.

Dr. Chang's operative note: The labrum is not a vestigial structure. It is the acetabular seal — it maintains the negative intra-articular pressure that holds the femoral head in the socket, and it distributes synovial fluid across the articular surface. In a total hip replacement, the labrum interacts with the acetabular component rim. If we leave a torn, fragmented labrum in place, we leave a source of persistent pain, a mechanical impingement risk, and a potential accelerant of polyethylene or ceramic wear. Repairing it takes twenty minutes. The benefit lasts the lifetime of the implant.

Phase 3 — Femoral Component Implantation and Limb Length Restoration

Femoral stem: Cementless high-offset femoral stem — selected to restore the patient's native femoral offset and correct the 1.2 cm limb length discrepancy identified pre-operatively
Bearing surface: Ceramic-on-ceramic (CoC) — chosen for its superior wear resistance and biocompatibility in an active 54-year-old patient with a long implant life expectancy
Trial reduction and assessment: Trial components confirmed equal limb lengths on fluoroscopy; hip stability tested through full range of motion — no impingement, no instability; soft tissue tension balanced

Final components were implanted and reduction performed. Post-reduction fluoroscopy confirmed restoration of the hip centre of rotation, equalisation of limb lengths, and correct component positioning. Pelvic obliquity, assessed intraoperatively, had corrected to neutral with limb length equalisation.

Lumbar Management — Conservative Strategy

Given the correction of pelvic obliquity and limb length achieved by the hip replacement, and the patient's tolerance for a structured rehabilitation programme, the decision was made to manage the L4–5 lumbar stenosis conservatively post-operatively — with structured spinal physiotherapy, core muscle strengthening, and serial clinical reassessment. Minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF) via a 3 cm incision was discussed as a contingency if lumbar symptoms failed to improve following hip rehabilitation. In the event, lumbar symptoms resolved substantially without spinal intervention.

Post-operative Management and Enhanced Recovery

ERAS Protocol

• Anaesthesia: Spinal anaesthesia with iliofascial compartment block — minimising systemic opioid requirements
• Multimodal analgesia: Iliofascial block + intravenous analgesia pump; oral fluids commenced at 2 hours post-operatively
• Dislocation precautions: None — DAA preserves the posterior capsule and short external rotators entirely; no positional restrictions required

Rehabilitation Programme (Dr. Chang's Sports Medicine Protocol)

• Day 1 post-operative: Ankle pumps; quadriceps isometric contractions; full weight-bearing ambulation with walking frame — permitted immediately due to excellent primary implant stability and intact muscular envelope
• Week 1: Progressive gait training; core muscle activation exercises targeting lumbar stabilisation; proprioceptive training for hip joint position sense
• Month 1: Stationary cycling; hydrotherapy; progressive resistance training for hip abductors and extensors
• Month 3: Return to low-intensity dance exercise and sustained walking
• Month 6: Return to swimming; daily 10,000-step walking achieved

Follow-up Outcomes

• Harris Hip Score at 6 months: 95/100 — excellent result
• Oswestry Disability Index (ODI) at 6 months: 10% — 80% reduction from pre-operative baseline; lumbar symptoms substantially resolved without spinal surgery
• Limb length: Equal bilaterally; pelvic obliquity resolved
• Radiography: Acetabular component at 42° inclination, 18° anteversion; femoral stem well-fixed; no radiolucent lines
• Functional status: Daily 10,000-step walking; low-intensity dance resumed; independent in all activities of daily living

Extended Case: Bilateral DDH with Staged DAA Total Hip Replacement in a Young Professional

Dr. Chang Xiao's DAA expertise extends to the most demanding DDH scenario: bilateral hip dysplasia in a young, high-demand patient where implant longevity and functional recovery are paramount. A 38-year-old Canadian marketing executive with bilateral Crowe Type I DDH and bilateral end-stage osteoarthritis underwent staged bilateral DAA total hip replacement — right hip first, left hip at six weeks. Ceramic-on-ceramic bearings were selected for both sides given the patient's age and activity level. At one-year follow-up, bilateral Harris Hip Scores were 97 and 96 respectively; the patient had returned to recreational tennis and international business travel. This case was enrolled in the Ruijin Hospital DAA registry, contributing to the evidence base for ceramic-on-ceramic bearing longevity in young active patients with DDH.

Expert Commentary — Dr. Chang Xiao

1. The Orthopaedic Sports Medicine Convergence: Replacement Plus Repair

Traditional joint replacement surgery focused exclusively on the arthritic joint — remove the damaged cartilage, implant the components, close. The soft tissue environment was considered irrelevant once the bearing surface was replaced. That thinking is outdated. The labrum, the capsule, the short external rotators — these structures interact with the implant, influence joint stability, affect fluid film lubrication of the bearing surface, and determine the patient's functional outcome. In this case, the labral tear was not incidental to the hip replacement — it was a source of persistent impingement that would have caused post-operative pain and accelerated ceramic wear if left unaddressed. Repairing it arthroscopically through the DAA incision added twenty minutes to the procedure and eliminated a problem that would otherwise have required a second operation. The convergence of joint replacement and sports medicine is not a novelty. It is the logical evolution of functional orthopaedics.

2. DAA: The Gold Standard for Active Patients

The direct anterior approach is not simply a smaller incision. It is a fundamentally different surgical philosophy. By operating through the natural intermuscular plane between tensor fasciae latae and sartorius, we preserve every posterior structure that protects against dislocation — the posterior capsule, the piriformis, the obturator internus, the gemelli. The patient wakes up with a new hip and an intact muscular envelope. There are no dislocation precautions. There is no gait deviation. There is no period of muscle weakness while the divided tendons heal. For a patient who wants to return to dance, to walking, to an active life — the approach is the rehabilitation. The posterior lateral approach cannot offer this. It is the right operation for some patients. It is not the right operation for this one.

3. The Spine-Pelvis-Hip Biomechanical Chain: Treating the Root Cause

Hip-spine syndrome is one of the most underappreciated diagnostic challenges in orthopaedics. Patients present with back pain and are sent to the spine surgeon. They present with hip pain and are sent to the hip surgeon. Neither surgeon considers the other joint. The result is that patients undergo spinal fusion for lumbar stenosis that is partly a consequence of pelvic obliquity from hip dysplasia — and the fusion fails to resolve their symptoms because the root cause was never addressed. In this case, the L4–5 stenosis was real — the MRI confirmed it, the nerve root compression was symptomatic. But the pelvic obliquity from the 1.2 cm limb length discrepancy was loading the lumbar spine asymmetrically and accelerating the degenerative process. Correcting the hip — equalising limb length, levelling the pelvis, restoring the centre of rotation — removed that asymmetric load. The lumbar symptoms resolved without spinal surgery. Every orthopaedic surgeon treating hip or spine disease must think across the entire biomechanical chain. The pelvis is the keystone. If the keystone is tilted, everything above and below it is under abnormal stress.

4. Precision and Technology: AI Planning and Intraoperative Navigation

Minimally invasive surgery is not simply about the size of the incision. It is about the precision of every decision inside that incision. AI-assisted pre-operative templating allows us to define the exact implant size, offset, and positioning angles before the patient enters the operating theatre — reducing intraoperative decision-making time and eliminating the trial-and-error that characterises conventional templating. Intraoperative fluoroscopy confirms component position in real time, with a target accuracy of within 2° for both inclination and anteversion. For a 54-year-old active patient with a ceramic-on-ceramic bearing, a 5° error in acetabular positioning is the difference between a 25-year implant and a 10-year implant. Precision is not a luxury in joint replacement. It is the determinant of long-term outcome.

How CMCS Shanghai Coordinated This Case

China Medical Concierge Shanghai (CMCS) supported Ms. Lawson's care pathway from initial overseas inquiry through six-month post-operative follow-up and return-to-activity clearance. Our coordination included:

• Pre-arrival review of pelvic radiographs, lumbar MRI, hip MR arthrography, and physiotherapy records; specialist referral to Dr. Chang Xiao's joint reconstruction and sports medicine team at Ruijin Hospital, Shanghai Jiao Tong University
• Arrangement of comprehensive pre-operative assessment at Ruijin Hospital: standing pelvic radiography with limb length measurement, lumbar MRI review, hip MRA review, and functional gait analysis — with AI-assisted pre-operative templating completed prior to the patient's arrival in Shanghai
• Bilingual interpretation during the pre-operative consultation — including detailed explanation of the DDH diagnosis, Crowe Type II classification, the DAA approach rationale, the single-stage labral repair strategy, ceramic-on-ceramic bearing selection, limb length correction planning, and the conservative lumbar management strategy with MIS-TLIF as contingency
• Facilitation of the patient's informed surgical consent — ensuring Ms. Lawson fully understood the single-stage strategy, the absence of post-operative dislocation precautions with DAA, the ERAS rehabilitation timeline, and the realistic return-to-activity milestones
• Surgical admission logistics: orthopaedic theatre scheduling, Hana traction table reservation, anaesthesia pre-assessment, and accommodation support for accompanying family in Shanghai
• On-site medical interpretation throughout the hospitalisation — including ERAS protocol guidance, Day 1 mobilisation support, post-operative radiograph explanation, and discharge planning
• Multimodal analgesia coordination: iliofascial block protocol explanation, oral analgesia transition guidance, and pain management liaison with Dr. Chang's nursing team
• Post-operative rehabilitation coordination in Shanghai: physiotherapy referral for the first two weeks prior to return travel; written rehabilitation programme translated into English for continuation with Ms. Lawson's physiotherapist in Australia
• Six-month follow-up coordination: Harris Hip Score and ODI assessment scheduling; radiographic follow-up; results translation and communication to Ms. Lawson's orthopaedic surgeon in Australia; return-to-dance and return-to-swimming clearance documentation
• Lumbar surveillance coordination: serial clinical assessment of L4–5 symptoms following hip correction; confirmation that spinal intervention was not required; ongoing communication with the Australian spine team regarding long-term lumbar monitoring

For international patients facing complex hip pathology — particularly those with developmental dysplasia of the hip, combined hip-spine syndrome, intra-articular labral tears, or prior treatment failures — the combination of DAA minimally invasive precision, integrated sports medicine labral repair, AI-assisted component planning, and the spine-pelvis-hip biomechanical expertise at Ruijin Hospital represents a standard of functional orthopaedic reconstruction that is genuinely at the international frontier. CMCS exists to connect patients with that expertise: ensuring every surgical option is evaluated, every biomechanical relationship is explained in their language, and every step from pre-operative templating to long-term return-to-activity rehabilitation is coordinated across borders with precision and care.

This case report is de-identified and published for educational purposes. All clinical details have been anonymized in accordance with patient privacy standards. CMCS Shanghai is a medical concierge service and does not provide direct medical care.