Sub-Specialty Hub
Sub-specialty patellofemoral care — anterior knee pain, chondromalacia, focal patellar cartilage lesions, patellar tendinopathy, and patellofemoral arthritis. A cartilage-first approach for younger patients, AMZ-TTO realignment when malalignment drives the pain, and high-volume patellofemoral arthroplasty (50–60 per year, onlay-design implants) when the cartilage is gone. By Dr. Sabrina Strickland at the Hospital for Special Surgery in New York.
Patellar pain and patellofemoral arthritis sit on a continuum: anterior knee pain at one end, end-stage cartilage loss at the other. The same complaint — "my kneecap hurts" — can come from a teenager with maltracking, a runner with patellar tendinopathy, a 35-year-old with a focal trochlear cartilage defect, or a 60-year-old with isolated end-stage patellofemoral arthritis. Treatment is matched to the cause: structured PT and selective injection for first-line care; progressive eccentric slow-resistance loading for tendinopathy; anteromedialization tibial tubercle osteotomy (AMZ-TTO) for malalignment-driven pain; distalization tibial tubercle osteotomy (Distal TTO) for inferior patellar cartilage wear; cartilage repair (MACI, OCA) for focal defects, with concurrent realignment when malalignment is also present; and patellofemoral arthroplasty (PFA) for isolated end-stage arthritis. Dr. Sabrina Strickland is a member of the International Patellofemoral Study Group, performs approximately 50 to 60 patellofemoral arthroplasties per year using onlay-design implants, and has published on patellofemoral arthroplasty outcomes, conversion to total knee, MDC thresholds for patellofemoral arthroplasty outcomes, and the cartilage-repair-with-realignment treatment algorithm.
Anterior knee pain — pain at the front of the knee around the kneecap — is one of the most common reasons patients are referred to a knee specialist. It is also one of the most under-diagnosed, because "kneecap pain" is a symptom, not a diagnosis. The right treatment depends on which underlying problem is driving the pain — muscle imbalance, tendinopathy, focal cartilage damage, malalignment, or isolated patellofemoral arthritis — and that requires a structured exam, the right imaging, and a clear understanding of the underlying mechanics.
This page is the sub-specialty hub for patellar pain and patellofemoral arthritis. It is paired with the patellar instability hub for patients whose kneecap also slips out of place — many patients have both. Here we cover what patellar pain means, how it differs from patellar tendinopathy, why malalignment and cartilage loss generate pain, the role of imaging and patellofemoral height measurement, the staged treatment ladder (PT → cartilage repair → AMZ-TTO → PFA → total knee), the cartilage-first philosophy for younger patients, the sub-specialty case for patellofemoral arthroplasty as a joint-preserving option, the PFA-vs-total-knee decision, recovery, risks, friction-log honest answers, insurance reality, and when to seek a sub-specialty second opinion.
The kneecap (patella) sits in front of the knee and slides up and down in a groove on the front of the thigh bone — the trochlear groove. Together they form the patellofemoral joint. Cartilage on the back of the kneecap and on the surface of the trochlea allows the joint to glide smoothly through the range of motion. Patellar pain is an umbrella term for pain at the front of the knee that comes from this joint or the soft tissues around it. It includes:
The two ends of the spectrum need different treatment plans. Patellar pain without structural damage may resolve with conservative care or, when there is a clear surgical cause, with realignment or cartilage repair. Patellofemoral arthritis cannot be reversed, but it can often be managed with cartilage-protecting non-surgical care — and, when isolated, treated with patellofemoral arthroplasty (a partial knee replacement that preserves the rest of the joint) without committing to a total knee. While this page is called "patellar arthritis," the clinical term is "patellofemoral arthritis." We use both throughout.
Patellar pain is typically a dull or sharp ache around or behind the kneecap. It is often worse with activities that load the patellofemoral joint:
Many patients also notice clicking, grinding, or popping (crepitus) when bending or straightening the knee. Crepitus alone is common and not always pathologic, but new mechanical symptoms — catching, locking, or a sense that something is moving inside the joint — can indicate a loose cartilage flap or osteochondral fragment that warrants imaging. Often these symptoms have been present for years at a low level. A change in weight, training intensity, or coming back to exercise after a long break can flare a previously tolerable problem into one that interferes with daily life.
One of the most common diagnostic errors in anterior knee pain is conflating patellar pain (joint-based) with patellar tendinopathy (tendon-based). The distinction matters because the rehab is different and the wrong program does not work for the wrong diagnosis.
Patellar tendinopathy — sometimes called "jumper's knee" — is pain in the patellar tendon at the lower pole of the kneecap. It is a tendon-loading problem. Most cases improve over 3 to 6 months with progressive heavy slow-resistance training, training-load adjustments, equipment review, and selective adjuncts. Tendons remodel slowly compared with muscle, which is why patients who try a few weeks of rest and stretching are often disappointed. Eccentric exercises — like decline single-leg squats — were the original gold standard, but more recent evidence shows heavy slow-resistance training is at least as effective and often better tolerated. The key is progressive loading, not the exact protocol. Working with a sports physical therapist to individualize the program is the first step. See 4 ways to manage patellar tendinopathy and eccentric cycling treatment for patellar tendinopathy for the rehab framing.
Patellofemoral pain is pain at the joint between the kneecap and the trochlea, driven by tracking, cartilage status, malalignment, or arthritis. It is treated with quadriceps and hip-stabilizer rehabilitation, sometimes bracing, sometimes injections, and sometimes realignment or cartilage repair. The two diagnoses can coexist in the same knee, but they need different rehab frameworks — running a tendinopathy loading protocol on a maltracking patellofemoral joint can flare both. Surgery for patellar tendinopathy is uncommon; surgery for patellofemoral pain is reserved for the structural cases.
Video: Dr. Strickland on patellar pain and patellar arthritis — what the kneecap, trochlea, and patellofemoral joint are; how malalignment and arthritis develop; and how the conversation with patients begins.The patella is the largest sesamoid bone in the body. Its job is to act as a lever, increasing the mechanical advantage of the quadriceps as it pulls through the patellar tendon onto the tibia. As the knee flexes from 0 to 90 degrees, the patella tracks down through the trochlear groove and the contact area between patellar and trochlear cartilage shifts. The forces across the patellofemoral joint can be several multiples of body weight in deep flexion — which is why squats, stairs, and getting out of a chair are the activities that flare patellar pain.
When the patella tracks normally and the cartilage is healthy, the joint glides without symptoms. Pain arises when one of three things changes:
Most patients have more than one of these contributing. A maltracking patella loads the lateral facet, the cartilage on that facet wears, and over years the wear becomes structural arthritis. This is why "treat the symptom" is rarely the right answer for patellofemoral pain — effective treatment usually addresses every contributing factor, not just the most obvious one. For the cartilage-side framing, see treatments of patellar chondral lesions.
Patella alta, an excessive TT-TG distance, trochlear dysplasia, and lateral retinacular tightness all cause the kneecap to track laterally and overload one facet. Identified on imaging.
A posteriorized tibial tubercle relative to the trochlear groove is associated with increased risk of patellofemoral arthritis — see Dr. Strickland's commentary on the sagittal TT-TG distance and patellofemoral arthritis risk.
A patellar dislocation is rarely just a soft-tissue event — the cartilage on the back of the patella and lateral trochlea can shear off the groove and snap back, producing chondral injury that drives later pain.
Weak quadriceps (especially the VMO) and weak hip abductors and external rotators allow the kneecap to track laterally and load the lateral facet. The single most addressable factor in conservative care.
Repetitive loading — running, jumping, kneeling, sudden ramp-ups in mileage or intensity — irritates the tissues around the patella. The most common scenario in active patients.
Each pound of body weight loads the patellofemoral joint several times over with each step. Decades of high-impact activity, prior knee surgery, or post-traumatic injury all accelerate cartilage loss in the patellofemoral compartment.
Most patients have more than one of these contributing — a runner with quadriceps weakness and patellar maltracking, for example, or a 50-year-old with a remote dislocation history and progressive cartilage thinning. Effective treatment usually addresses every contributing factor.
The vast majority of patellar pain improves with structured non-surgical care. Quadriceps strengthening (closed-chain in pain-free range), VMO activation, hip-abductor and external-rotator strengthening, posterior-chain (glute and hamstring) work, core control, balance and proprioception, and stretching of the iliotibial band, quadriceps, and calves — this is the most under-executed step in patellar pain care, and the difference between a well-executed PT program and a poorly executed one is often the difference between a good and a poor outcome.
For adolescents in particular, structured rehabilitation is the priority. Most adolescents with patellofemoral pain do not have structural cartilage damage and do not need surgery; their long-term prognosis improves with consistent quadriceps and hip-stabilizer strengthening, training-load management, and time. See how to improve long-term prognosis for adolescents with patellofemoral pain for the framing — the adolescent patellofemoral patient is rarely a surgical candidate, and presenting one as a surgical case is usually wrong.
For older patients with structural disease, conservative care is still the right starting point: cartilage-protective exercise (cycling, swimming, elliptical), weight optimization where applicable, NSAIDs for flares, and selective injection therapy (cortisone for short-term symptom control during a flare; hyaluronic acid or PRP for arthritic pain in selected patients; PRP for tendinopathy in selected cases). Injections are bridges, not destinations — they buy time to do the strengthening and load-management work.
The diagnosis of patellar pain is built from history, physical exam, and targeted imaging. Imaging is appropriate when conservative care has not produced the expected response, when there is a history of dislocation or significant injury, when mechanical symptoms suggest a loose body or osteochondral fragment, or when surgery is being considered.
AP, lateral, Merchant (axial sunrise) view, and standing alignment films. The lateral X-ray is used to measure patellar height by the Caton-Deschamps or Insall-Salvati index. The Merchant view shows patellar tilt and lateral subluxation in early flexion. Joint-space narrowing on the Merchant view is the hallmark of patellofemoral arthritis — weight-bearing technique matters because non-weight-bearing films can miss arthritis between the tibia and femur.
MRI visualizes the patellar and trochlear cartilage, the medial patellofemoral ligament, the patellar tendon, the retinaculum, and looks for loose bodies. It is the single most informative study when conservative care has failed. Cartilage scoring on MRI — including structured MRI scoring of patellofemoral osteoarthritis — characterizes chondromalacia, focal defects, and subchondral bone changes. 3D imaging of the patellofemoral joint is being used in increasingly sophisticated planning for cases where the geometry matters.
When realignment surgery is being considered, axial measurement of the tibial tubercle to trochlear groove distance (TT-TG) on CT or MRI characterizes the bony component of maltracking. Patellofemoral height (Caton-Deschamps), TT-TG distance, sagittal TT-TG (an under-appreciated metric — see the increased risk of patellofemoral arthritis with posterior tubercle position), and trochlear morphology together drive the realignment plan.
Patellofemoral disease when unresponsive to conservative care is one of the few orthopedic problems where the surgical decision is not "operate or don't" — it is "which operation, in which combination, and in what order." The ladder progresses from joint-preserving to joint-resurfacing. The correct rung depends on cartilage status, alignment, and patient factors. The conservation hierarchy outlined in considerations for patellofemoral joint preservation vs. patellofemoral arthroplasty is the framework.
Quadriceps and hip-stabilizer strengthening, weight optimization, cartilage-protective cross-training (cycling, swimming, elliptical), NSAIDs for flares, and selective cortisone, PRP, or hyaluronic acid injection. First-line for almost everyone — including most adolescents and most patients with early structural disease.
For younger patients with a focal full-thickness cartilage defect on the patella or trochlea (typically 2–10 cm² for MACI; larger lesions with bone involvement go to osteochondral allograft). Combined with AMZ-TTO in the same operation when malalignment is also present — uncorrected malalignment is one of the main reasons cartilage repair fails. See MACI cartilage repair and cartilage transplantation (OCA).
The Fulkerson osteotomy — a controlled cut and repositioning of the bony attachment of the patellar tendon, moving the tubercle anteriorly and medially. Offloads the distal-lateral facet of the patella where maltracking-driven cartilage wear concentrates. Stand-alone for malalignment-driven pain without large cartilage defects, or combined with cartilage repair when both problems are present. See joint preservation and osteotomy.
For end-stage isolated patellofemoral arthritis with normal medial and lateral compartments. Resurfaces only the kneecap and the trochlea — the cruciate ligaments, menisci, and tibiofemoral compartments are preserved. The major joint-preserving alternative to total knee replacement for the right patient. Discussed in detail below.
Reserved for the patellofemoral patient who has progressed to multi-compartment arthritis, or for patients whose anatomy or activity goals make PFA inappropriate. PFA can be converted to total knee replacement later if the medial or lateral compartments deteriorate — see the section on PFA-to-TKA conversion below.
The ladder is conceptual — in practice the decision is often made up front based on the imaging-based picture rather than progressing rung by rung after recurrent failures. A 28-year-old with a 4 cm² focal patellar chondral defect, mild patella alta, and an elevated TT-TG distance is a candidate for combined cartilage repair plus AMZ-TTO at one operation, not three sequential surgeries. A 65-year-old with bone-on-bone isolated patellofemoral arthritis and pristine medial and lateral compartments is a PFA candidate, not a candidate for cartilage repair.
For younger active patients with focal full-thickness patellar or trochlear cartilage damage, the goal is to preserve their native joint. Joint replacement — even partial replacement — in a 30-year-old commits them to a revision conversation in their lifetime. Cartilage repair, when feasible, restores the joint surface without committing to an implant.
The main cartilage-restoration options for the patellofemoral joint:
The single most important point about patellofemoral cartilage repair is that correcting alignment matters as much as the cartilage work itself. Dr. Strickland's technical note on treatments of patellar chondral lesions describes the algorithm: "correcting patellar malalignment and instability is critical for the success of cartilage repair procedures… we recommend that TTO and MPFL reconstruction be performed with MACI procedures of the patella when the anatomic pathology and pertinent patient history are present." A pristine cartilage repair on a still-maltracking patella is set up to fail. For the combined-pathology population, see understanding patellofemoral instability and cartilage lesions, the podcase on patellofemoral instability and cartilage lesions, the related atraumatic medial patellar facet lesions, and Dr. Strickland's assessment of patellar vascularity after lateral parapatellar approach — a technical consideration for patellar cartilage repair via the lateral approach.
An interesting nuance: patella alta patients may experience less severe cartilage damage after instability than non-alta patients in some series — the height itself may protect the cartilage from contact during dislocation events, even though it predisposes to the dislocations in the first place. The clinical implication is that imaging the cartilage carefully on MRI matters more than assuming "alta = severe wear."
Patellofemoral arthroplasty is a partial knee replacement that resurfaces only the back of the kneecap and the trochlear groove. The medial and lateral compartments, the cruciate ligaments, and the menisci are all preserved. For the right patient — isolated end-stage patellofemoral arthritis with normal medial and lateral compartments and stable ligaments — PFA preserves natural knee biomechanics in the rest of the joint and is a less invasive alternative to total knee replacement. See patellofemoral arthroplasty for the dedicated discussion.
This is the single most important sub-specialty point on this page. National Joint Registry data published in 2025 (analyzed in Dr. Strickland's commentary at lower revision rates after patellofemoral arthroplasty for high-volume surgeons) showed that surgeons who perform more than 5 patellofemoral arthroplasties per year have lower revision rates and lower complication rates than lower-volume surgeons. The same dataset showed that onlay-design trochlear components had better outcomes than inlay designs, because onlay implants allow rotation of the trochlear component to optimize patellar tracking. Dr. Strickland performs approximately 50 to 60 patellofemoral arthroplasties per year and favors onlay-design implants. PFA is one of the operations where high volume genuinely produces measurable differences in revision rates and outcomes.
The classic indications are:
Recent series have also documented that medial UKA improves pain and function despite patellofemoral joint degeneration in selected patients — the patellofemoral compartment is not always the dominant source of symptoms in a multi-compartment knee. Sub-specialty judgment is needed to decide which compartment is driving the pain.
Patellar height does not correct itself with arthroplasty — it's an anatomic fact of the knee, not an implant-correctable parameter. Dr. Strickland's study on the effect of patellofemoral arthroplasty on patellar height documents this. Pre-operative measurement of patellar height by Caton-Deschamps is a routine part of the work-up.
For tracking PFA outcomes meaningfully, Dr. Strickland's group has published on establishing minimal detectable change (MDC) thresholds for Kujala scores after patellofemoral arthroplasty — the threshold a patient's score has to cross before the change is real, not noise. This is the kind of statistical work that ensures outcome reporting in this population is honest.
| Feature | PFA | Total Knee Replacement |
|---|---|---|
| Best for | Isolated end-stage patellofemoral arthritis with normal medial/lateral compartments and intact ligaments | Multi-compartment arthritis, or PF arthritis combined with significant medial/lateral wear |
| What's preserved | ACL, PCL, both menisci, medial and lateral compartments, native joint kinematics | None of the above — all three compartments are resurfaced |
| Recovery | 3–6 months — weight-bearing as tolerated immediately, return to recreational sport (cycling, golf, doubles tennis) at 3–6 months | 3–6 months — similar timeline but a larger physiological insult and longer return to high-demand activity |
| Volume effect | Significant — surgeons with higher PFA volume show lower revision rates (NJR data, 2025) | Significant but less pronounced — TKA is much higher-volume nationally |
| Implant design | Onlay trochlear components have better outcomes than inlay (NJR data, 2025); rotation of trochlear component optimizes tracking | Multiple well-validated implant systems |
| Convertible | Yes — can be converted to total knee if other compartments later wear out | Revision TKA is more complex than primary; pursued when needed |
| Trade-off | Joint-preserving for the right patient; depends on isolation of the disease to the PF compartment | Definitive resurfacing; commits to all three compartments |
Patient selection is the heart of the PFA-vs-TKA decision. The right patient for PFA is the patient whose pain truly comes from the patellofemoral compartment in isolation. Standing weight-bearing X-rays, careful MRI review, and an honest clinical assessment of where the pain is coming from are the work-up. Conversion of patellofemoral arthroplasty to total knee replacement is feasible when the medial or lateral compartments later wear out — recent retrieval-analysis work has highlighted infection risk after conversion as something to watch for, which is one reason careful patient selection at the index PFA matters.
For patients with combined patellofemoral arthritis and patellar instability, treating patellofemoral arthritis and patellar instability often requires concurrent stabilization — arthroplasty alone in an unstable knee is set up to fail.
Patellofemoral surgery (whether arthroscopy with debridement, AMZ-TTO, cartilage repair, or PFA) is performed as an outpatient procedure in most cases — you go home the same day. Combined cases (TTO + cartilage repair, for example) may have additional recovery considerations reviewed at consultation.
Cold-compression devices and quadriceps muscle stimulators (when prescribed) help reduce swelling and support muscle reactivation in the first weeks. The block typically wears off over the first 12 to 24 hours, during which the leg is numb and weight-bearing requires the brace and crutches.
Recovery is procedure-specific. The dates below are general guidelines; your specific plan depends on which procedures were performed and on your individual healing.
| Phase | Arthroscopy / debridement | AMZ-TTO | MACI / OCA cartilage repair | Patellofemoral arthroplasty |
|---|---|---|---|---|
| Weight-bearing | As tolerated | Protected 4–6 weeks | Protected 4–6 weeks | As tolerated |
| Brace | None or light | Hinged brace 4–6 weeks | Hinged brace 4–6 weeks | None or light |
| Range of motion | Weeks 0–4 | Weeks 0–8 | Weeks 0–10 | Weeks 0–6 |
| Strengthening | Weeks 2–6 | Months 2–5 | Months 3–6 | Weeks 2–12 |
| Return to running | 4–6 weeks | 4–5 months | 9–12 months | Generally not recommended |
| Return to recreational sport | 2–3 months | 5–6 months | 12–18 months | 3–6 months (cycling, golf, doubles tennis) |
Across all of these, quadriceps and hip-stabilizer rehabilitation is the single most important factor in a successful outcome. The procedure restores the joint surface or realigns the mechanics; the rehab restores the function. The two factors that most consistently slow recovery are inconsistent physical therapy attendance and rushing back to high-impact activity before clearance.
Patellofemoral surgery is well-established with predictable outcomes for well-selected patients, but no surgery is risk-free. Risks reviewed at consultation include:
Outcomes are generally good in well-selected patients, but results depend on individual anatomy, adherence to rehab, and overall health. Specific risks for your case depend on imaging, prior surgeries, concurrent procedures, and goals — reviewed at consultation.
The friction-log: the four concerns we hear most often before patellofemoral surgery, with honest answers.
It depends on the imaging. PFA is appropriate when the arthritis is isolated to the patellofemoral compartment with normal medial and lateral compartments and intact ligaments. Many patients are told they need a total knee replacement when in fact they have patellofemoral-predominant disease and would be better served by a partial replacement. The work-up is standing weight-bearing X-rays, a careful MRI, and an honest clinical assessment of where the pain is coming from. Bringing your prior imaging to a sub-specialty consultation is the right starting point.
Yes — for PFA more than for many other operations. National Joint Registry data published in 2025 showed surgeons performing more than 5 PFAs per year have lower revision rates than lower-volume surgeons. Onlay-design implants outperformed inlay designs in the same dataset. Dr. Strickland performs approximately 50 to 60 PFAs per year using onlay implants. PFA is a sub-specialty operation; the difference between high- and low-volume in this specific procedure shows up in revision-rate data.
Almost certainly not. For young patients with focal full-thickness cartilage damage and otherwise reasonable cartilage elsewhere, the goal is joint preservation — cartilage repair (MACI or osteochondral allograft) combined with realignment (AMZ-TTO) when malalignment is part of the picture. A partial replacement at 32 commits you to a revision conversation in your lifetime. The right operation depends on lesion size and location, alignment, and prior treatment history — reviewed in detail at consultation.
Dr. Strickland's post-operative protocol is opioid-sparing. A periarticular block placed around the knee joint during surgery helps reduce pain during the first day after surgery; multimodal pain medications (acetaminophen, anti-inflammatories where appropriate) carry most of the work after that. Short-course opioid prescriptions are used for the first few days at most for the majority of patients, and many patients use very little. The protocol is reviewed at consultation.
AMZ-TTO, cartilage repair (MACI, OCA), patellofemoral arthroplasty, and total knee replacement are covered by all major commercial insurance plans, Medicare, and most self-funded and union plans when the diagnosis and indication for surgery meet medical-necessity criteria. The variables that drive your specific out-of-pocket cost are:
The Patella LIFT procedure, when performed under the FDA PELICAN trial, has separate considerations because it is investigational. PRP and some biologic injections are not always covered — we review the specifics during your consultation. Before surgery, our office verifies your benefits, obtains pre-authorization where required, and reviews the estimated out-of-pocket cost with you. For benefits verification or to discuss self-pay arrangements, call us at (646) 960-7227 or contact the office.
Patellofemoral disease is one of Dr. Strickland's primary clinical and academic areas. She is a member of the International Patellofemoral Study Group, performs approximately 50 to 60 patellofemoral arthroplasties per year, and has published on PFA volume and revision rates, PFA conversion to total knee, MDC thresholds for patellofemoral arthroplasty outcomes, the cartilage-repair-with-realignment treatment algorithm, MRI scoring of patellofemoral osteoarthritis, and patellofemoral height as an outcome predictor.
A sub-specialty second opinion is particularly worth seeking when:
Dr. Strickland sees patellofemoral patients at two offices, both of which work with patients traveling in from outside the immediate area:
Many patients travel to New York for sub-specialty patellofemoral care — particularly for patellofemoral arthroplasty when their local surgeon is low-volume, for combined cartilage repair plus realignment when the local recommendation was a partial or total knee replacement, and for second opinions on prior failed patellofemoral surgery. We coordinate consultation, imaging review, and surgery scheduling to minimize travel for out-of-state patients.
A dull or sharp ache around or behind the kneecap that worsens going down stairs, sitting for long periods with the knee bent (the "theater sign"), wearing high heels, kneeling, and squatting. Pain that is worse going downstairs than upstairs is one of the more specific patterns for patellofemoral involvement. Many patients also notice clicking, grinding, or popping (crepitus). New mechanical symptoms — catching, locking, or a sense that something is moving in the joint — can indicate a loose cartilage flap or osteochondral fragment that warrants imaging.
Patellar pain (sometimes called patellofemoral pain syndrome) is pain at the joint between the kneecap and the trochlea — driven by tracking, cartilage status, or malalignment. Patellar tendinopathy ("jumper's knee") is pain in the tendon at the lower pole of the kneecap and is a tendon-loading problem, not a joint problem. Tendinopathy is treated with progressive heavy slow-resistance and eccentric loading; patellofemoral pain is treated with quadriceps and hip-stabilizer rehabilitation, and sometimes realignment or cartilage repair.
Patellar pain is a symptom that can come from many causes — muscle imbalance, tendinopathy, early cartilage softening, maltracking — without visible joint-space loss on x-ray. Patellofemoral arthritis is end-stage cartilage loss on the back of the kneecap and the front of the trochlea, visible on x-ray as joint-space narrowing. Patellar pain may resolve with non-surgical care; patellofemoral arthritis can be managed but the cartilage loss does not reverse.
Many patients improve with rest, activity modification, ice, NSAIDs, structured physical therapy targeting the quadriceps and hip stabilizers, bracing, and selective injection therapy. Surgery is reserved for cases that fail several months of well-executed conservative care or that have a clear surgical target on imaging.
AMZ-TTO (the Fulkerson osteotomy) is a controlled cut and repositioning of the bony attachment of the patellar tendon. The tubercle is moved anteriorly and medially, which offloads the distal-lateral facet of the patella and corrects lateral maltracking. It is the realignment procedure of choice for patellar pain driven by malalignment with distal-lateral cartilage wear, often combined with cartilage repair when a focal defect is present.
Patellofemoral arthroplasty is a partial knee replacement that resurfaces only the back of the kneecap and the trochlear groove. The medial and lateral compartments, the cruciate ligaments, and the menisci are all preserved. PFA is appropriate for patients with isolated end-stage patellofemoral arthritis, normal medial and lateral compartments on x-ray, intact ligaments, and reasonable alignment. It is a less invasive alternative to total knee replacement for the right patient.
Yes. National Joint Registry data published in 2025 showed surgeons performing more than 5 PFAs per year have lower revision rates and lower complication rates. Onlay-design implants outperformed inlay designs in the same dataset. Dr. Strickland performs approximately 50 to 60 PFAs per year using onlay implants, which allow rotation of the trochlear component to optimize patellar tracking.
Focal full-thickness cartilage defects can be treated with cartilage repair — MACI, osteochondral allograft (OCA), or other cartilage-restoration techniques. The right option depends on lesion size, depth, location, and whether subchondral bone is involved. When malalignment is present alongside the cartilage defect, correcting alignment with an AMZ-TTO at the time of cartilage repair is important — uncorrected malalignment is one of the main reasons patellar cartilage repair fails.
Most patellar tendinopathy improves over 3 to 6 months with progressive heavy slow-resistance and eccentric loading, training-load adjustments, and selective adjuncts. Tendons remodel slowly compared with muscle, so a few weeks of rest and stretching is rarely enough. Stubborn cases may benefit from PRP or, rarely, surgery. The first step is working with a sports physical therapist to individualize a progressive loading program.
Yes. If the medial or lateral compartments later develop significant arthritis, the patellofemoral implant can be converted to a total knee replacement. Recent retrieval-analysis work has highlighted infection risk after conversion, which is one reason careful patient selection at the index PFA matters. For many isolated patellofemoral arthritis patients, however, PFA remains a durable joint-preserving option that delays or avoids total knee replacement entirely.
This page is grounded in Dr. Strickland's published commentary, technical notes, and patient education. Selected references:
For patients whose kneecap also slips out of place, see the paired patellar instability hub and the MPFL reconstruction surgery page. For the realignment side of patellofemoral care, see joint preservation and osteotomy. For cartilage repair options, see MACI cartilage repair and cartilage transplantation (OCA). For multi-compartment knee arthritis, see knee arthritis. For chondromalacia and tendonitis at the front of the knee, see knee chondromalacia, arthritis, and tendonitis. For complex anatomy where computer-guided planning is helpful, see Mako robotic-assisted surgery.
For Dr. Strickland's published research and editorial commentary on patellofemoral disease, the source-grounding table above lists the references used on this page; for the broader publication record, see research & publications.
Medical Disclaimer. This content is for informational purposes only and does not constitute medical advice, diagnosis, or treatment. Surgical and non-surgical orthopedic care should always be discussed with a board-certified orthopedic surgeon who has reviewed your imaging, history, and physical examination. Individual outcomes vary based on diagnosis, anatomy, comorbidities, surgical technique, and adherence to rehabilitation. Modern patellofemoral surgery (cartilage repair, AMZ-TTO, patellofemoral arthroplasty) is well-established for well-selected patients but no procedure is a guaranteed fix. The Patella LIFT procedure is investigational and is offered only under FDA clinical-trial protocols. The volume figures and outcome statistics on this page are drawn from National Joint Registry data and from Dr. Strickland's published clinical and academic work, cited in the source-grounding table above.
If your kneecap pain is limiting daily life and conservative care has not resolved it — or if you have been told you need a total knee replacement and want a second opinion on patellofemoral-only options — bring your imaging to a sub-specialty consultation in NYC or Stamford, CT.
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