Kneecap Dislocation & Patellar Instability Care in Bethlehem
When the kneecap (patella) slips partly or fully out of its groove on the thigh bone, it can tear the ligament that holds it in place and leave the knee feeling unstable. Dr. Michael Hendel, MD, PhD evaluates and treats patellar instability for patients across Bethlehem, Allentown, Easton, and the greater Lehigh Valley — from a first-time dislocation in a young athlete to recurring episodes that keep interrupting practice and games. He completed both his residency and his sports medicine fellowship at Hospital for Special Surgery.
The kneecap normally tracks in a groove on the femur. Shallow anatomy, ligament laxity, or malalignment can let it slip sideways — from subtle subluxation to a full dislocation, most often in adolescents and young athletes.
Common Signs
- The kneecap visibly shifting or dislocating
- Sharp pain and a “giving way” sensation
- Swelling around the kneecap
- Pain on stairs or with prolonged sitting
- Apprehension with twisting or cutting
Evaluation
Dr. Hendel starts with a focused exam of kneecap tracking, ligament laxity, and alignment. Imaging — typically X-rays and often an MRI — helps define the soft-tissue injury, any loose fragments, and whether the cartilage surface was damaged when the kneecap went out. That information guides whether bracing and therapy are enough, or whether surgical stabilization is the better next step.
Non-Surgical Care
Not every dislocation needs an operation. For many first-time events without loose fragments, Dr. Hendel typically starts with:
- VMO and hip strengthening physical therapy
- Patellar bracing or taping
- Activity modification while the soft tissues settle
Nonoperative care is also appropriate when symptoms are mild, when a single episode has not recurred, and when imaging does not show a problem that surgery would clearly fix.
Surgical Options — MPFL Reconstruction & Realignment
When the kneecap keeps coming out, or when the checkrein ligament is clearly incompetent, surgery can restore stability.
- MPFL reconstruction — rebuilds the medial patellofemoral ligament, the primary soft-tissue checkrein that keeps the kneecap from sliding outward
- Tibial tubercle osteotomy (TTO) — for bony malalignment, when the attachment of the patellar tendon on the shin needs to be moved to improve tracking
- Cartilage treatment — when the joint surface was injured during a dislocation (see also cartilage restoration)
Combined procedures (for example MPFL with TTO, or with cartilage restoration) are planned around your anatomy and goals. Related knee problems — meniscus tears, ACL injury, or focal cartilage defects — are addressed on their own pages: knee surgery, meniscus tear care, and ACL reconstruction.
Recovery After MPFL Reconstruction
Every surgical patient receives a written, milestone-based rehabilitation protocol from Dr. Hendel’s library. Timelines below are the typical ranges already published on his site for MPFL care; your personal plan may differ.
MPFL reconstruction (without osteotomy) — typical outline
- Weeks 0–4: hinged knee brace locked in extension for walking; weight bearing as tolerated in the brace; motion starts limited (about 0–60 degrees early, progressing toward 90 degrees by week 4)
- Weeks 4–8: progress to full weight bearing; unlock the brace; full motion expected by about weeks 6–8; early strengthening and bike work as motion allows
- Weeks 8–16: progressive strengthening, single-leg work, and balance
- Months 4–6+: running progression around 4+ months; agility and sport-specific drills; full clearance typically around 5–7 months after functional testing
When a tibial tubercle osteotomy is added: early weight bearing is more protected (often toe-touch for about 2–4 weeks) while the osteotomy heals; later milestones follow a similar return-to-sport window once healing allows.
A shorter summary also used on the site: weeks 0–6 focus on brace and controlled motion; weeks 6–16 on progressive strengthening; months 4–7 on sport-specific training and return with clearance.
As with any surgery, risks include knee stiffness, recurrent instability, and, when a tibial tubercle osteotomy is performed, fracture or symptomatic hardware.