Patellofemoral Arthralgia

Patellofemoral arthralgia

HARLEN C. HUNTER, DD., FACOS, FAOAO Chesterfield, Missouri

This article will explore the causes of patellofem- Pain in the patellofemoral oral arthralgia in a series of 844 cases. Diagnosis articulation is best described as and management will be described as employed in "patellofemoral arthralgia." This may these cases and documented in the literature. be due to any of various causes. In a series of 844 cases seen in a sports Biomechanics of the patella medicine clinic, the pain was The patella is balanced in the patellofemoral attributed to subluxation of the groove by a medial force of the vastus medialis patella or malalignment in 396 muscle opposed by a lateral force of the iliotibial instances, patellar tendinitis in 346, band or tract and lateral retinaculum. Also, a su- quadriceps tendinitis in 60, and perior force of the quadriceps muscle is opposed by medial plica in 42. The diagnostic the patellar tendon (Fig. 1). features are described. Conservative The patella is subjected to powerful forces dur- management is attempted first and is ing knee movement, that is, patellofemoral com- designed to allow participation in pression force and quadriceps muscle tension sports to the extent possible. force. Recurrent or refractory problems The patellofemoral compression force is estimat- usually can be handled with ed to be 1/2 to 11/2 times the body weight during arthroscopic surgery or operative walking and 3 to 4 times body weight while climb- procedures on the soft tissues. ing stairs, and it may reach 7 to 8 times the body weight with squatting. After 30 degrees of flexion, this force rises from 1 times the body weight to 4 times at 60 degrees of flexion." Quadriceps tension force rises after 15 degrees of flexion. This force is 1 times the body weight dur- Anterior knee pain is a frequent complaint in ing walking, 3 1/2 times body weight while climbing younger athletes. Those participating in basket- stairs, and may reach 5 times the body weight with ball, football, track, baseball, hockey, and gymnas- squatting. If the balance of these biomechanical tics are most often affected. The pain is aggravat- forces is disturbed, pathologic changes may result. ed by jumping, lifting heavy weights, stair climbing, and sitting in tight places. Causes of patellofemoral joint pain The term "chondromalacia patellae" has been A total of 844 cases of patellofemoral arthralgia applied to this clinical syndrome. "Chondromala- were seen in the clinic setting from through cia patellae," however, actually describes the 1979 Of these, 396 cases were due to subluxating pathoanatomic finding of a softening and fissuring 1982. patella, 346 cases to patellar tendinitis, 60 cases of of the articular patellofemoral cartilage. This is a quadriceps tendinitis, and cases of medial plica. pathologic, not clinical, diagnosis. Moreover, ac- 42 The symptoms, diagnosis, and treatment of these cording to Insa11,2 chondromalacia may or may not causes of patellofemoral arthralgia will be dis- cause pain and sometimes is an incidental finding. cussed. Because pain around the patella has been attributed to various causes, and may or may not be due to Subluxating patella and malaligiunent the presence of chondromalacia patellae, a term syndrome that describes the clinical diagnosis of pain in the Outerbridge and Dunlop have tabulated factors patellofemoral articulation is preferable. Al- contributing to subluxating patella or malalign- though several terms, such as "patellar pain syn- ment syndrome. These include the following: (1) drome, have been employed, the term "patellofem- Factors increasing the "Q" angle, such as wide fe- oral arthralgia" best describes pain in the male pelvis, genu valgus, laterally placed tibial tu- patellofemoral joint that may be due to any of var- berosity, patella alta, and flat lateral femoral con- ious causes.4 dyle; (2) lax medial capsular retinaculum, due to a

Patellofemoral arthralgia 580/69 pain was dull and aching. In this series it was cen- tered in the front of the knee, but pain may be an- teromedial or generalized in location.2.5 Addition- al complaints include buckling, instability, locking, stiffness, swelling, and popping. In the ad- vanced cases, grinding or grating sensations occur at the patella.5 The symptoms are aggravated by activities such as getting out of a chair, climbing steps, jumping, maximal weight-lift training, kneeling, running with sudden change of direction or cutting back, and sitting in a confined space with the knees flexed (cinema or movie sign).2.5 Fig. 1. Four forces on the patella. Locking of the knee may occur, and such locking from a subluxated patella is a pseudolocking: The Anterior knee cannot be extended completely but can be superior completely flexed, unlike the locking in a meniscal injury. It is probably caused by hamstring muscle illiac spasm secondary to the subluxation.5 spine Physical findings of patellofemoral arthralgia that results from subluxating patella or malalignment syndrome include tenderness with percus- sion, increased quadriceps, or "Q," angle, (Fig. 2),9 and squinting patellae. The latter are noted if, with the patient standing, feet together, the patellae face toward each other instead of straight ahead. This is usually due to increased external tibial torsion and femoral anteversion resulting in an increased Q angle. 19 Excessive foot pronation is also a feature of this malalignment.1 The compression test will give positive results. In this test the knee is in slight flexion so that the Patella patella contacts the femoral grove; direct patellofemoral compression produces tenderness. 2.11 The apprehension test will be positive as well; that is, the patient shows apprehension when the examin- Tibial er pushes the patella laterally across the lateral tuberosity femoral condylar surface. 5 The tibial rotation test will yield negative results in malalignment (but not in a torn medial meniscus).2 X-ray films of the knee should be taken in the Fig. 2. Measurement of "Q" angle. anteroposterior, lateral, and sunrise positions. The lateral view is helpful in the detection of a high- riding patella (patella alta) using the Insall method (Fig. 3). The sunrise view may show abnormal torn or stretched retinaculum; (3) vastus medialis relationships between the patellar facets and the muscle insufficiency, caused by high insertion of intercondylar groove of the femur or tightness of the muscle on the patella; and (4) tight lateral cap- the lateral ligaments and muscles (Fig. 4). sular retinaculum (excessive lateral pressure syndrome). Management Treatment of recurrent subluxation of the patella Diagnostic features varies from nonoperative methods to rather formi- The presenting complaints of the 396 cases of sub- dable operative procedures. Initially, all patients luxating patella and malalignment syndrome should be tried on a well-managed rehabilitation were pain and giving-way of the knee when the program. knee was in a near fully extended position. The The conservative program in this clinic consists

581/70 September 1985/Journal of AO/0ml. 85/no. 9 Patella

Tendon

Fig. 3. Insall method of measuring relative patella and patellar tendon length. On a lateral x-ray view of the knee, the longest diagonal length of the patella and the length of the patellar tendon are measured. A 1:1 ratio is normal. (Modified from Insall and coworkers.") Fig. 4. Typical sunrise views. Left: Patella lying normally in groove. Center: Tightness of lateral muscles and ligaments. Right: Inad- equately developed lateral condyle.

of 6 phases: (1) Control of symptoms; (2) progres- ing against the wall for a count of 5 seconds, then sive resistance exercises; (3) physical therapy mo- repeating 10 times for 3 sets. The same isometric dalities; (4) running program; (5) braces, orthotics; exercise can be done at 15 and 0 degrees of flexion. and (6) maintenance program. A new device, Knee Master (Orthodynamics), Our program for symptomatic control leaves the measures pounds of force exerted by the isometric responsibility for activity curtailment to the pa- contraction. tient. Activities are restricted only by pain; there Isotonic quadriceps exercises are the major exer- is no evidence that participation in sports causes cises for a subluxating patella. The limited arc of the condition to become worse. 0-30 degree exercises are used because of the in- Aspirin is the primary drug of choice. It has been creased patellofemoral compression force above 30 shown that salicylates inhibit cathepsin, thus degrees of flexion,9 and the major medial force on stopping cartilage breakdown. 512 Chondromala- the patella is the vastus medialis. At first the cia is thought to result when the rate of chemical weight of the foot is used, then a shoe, and finally breakdown of cartilage, caused by protease cathep- 21/2-5 pounds of weight is used in this limited arc sin, exceeds the rate of synthesis. 12 The usual dos- (Fig. 5). age is 3 tablets of aspirin 3 times a day. If the pa- For isotonic hamstring exercises, a gym bag, tient cannot tolerate the aspirin, then anti- purse, or mechanical gym devices are used. With inflammatory drugs are used. Corticosteroids are the patient in the prone position, the knee is flexed not employed because they increased the rate of to the buttocks with 3 sets of repetitions, first us- cartilaginous degradation. 9 Progressive resistance ing no weight, then advancing to 2, 5, and 10 exercises are composed of isometric and limited arc pounds until reaching two-thirds of the maximal isotonic quadriceps exercises and isotonic hamstring exercises. Isotonic calf and anterior tibial exercises and stretching exercises are also used. Quadriceps stretching exercises daily seem to relieve some of the symptoms. Straight leg-raising exercises consisting of 15 repetitions in 3 sets daily are recommended. If no pain occurs without weights, then a boot is added; the weight pro- gresses up to 30 pounds, in 5-pound increments. One isometric knee exercise is performed with the patient supine. A pillow is folded under the knee, and the patient pushes the knee down at- tempting to straighten it, holds for 5-10 seconds, and repeats 25 times, twice daily. Another isometric exercise can be performed by sitting on a table or standing with the knee flexed 30 degrees push- Fig. 5. Limited arc knee extension exercise.

Patellofemoral arthralgia 582/71 if no improvement occurs in 2 months, if symptoms worsen over the first month, or if symptoms become recurrent. Surgery is indicated when conservative therapy has failed in 1 or 2 months. Operative treatment is divided into arthroscopic surgery and formal operative techniques on the soft tissue about the knee. Certain methods of bone surgery may be employed in the skeletally mature patient. Arthroscopic surgical procedures on subluxating patella and malalignment syndrome are diagnostic, chondroplasty, or lateral retinacular release. Fig. 6. A. Normal patellofemoral configuration. B. Typical later- Arthroscopy provides a means of diagnosing mala- al compression of patella on femur in malalignment disorders. C. Forces of compression in malalignment syndromes with tight lignment problems and allowing definitive sur- lateral band. D. Realignment of patella after release of lateral re- gery. Arthroscopy of the patellofemoral joint using tinaculum. the inferior lateral or superior medial portals shows the patellofemoral tracking as the knee is brought through its range of motion. Chondroma- weight lifted by the quadriceps. Isotonic calf and lacia of the patella may be shaved by the mechani- anterior tibial exercises are carried out by toe cal shavers under direct arthroscopy. The shaving raises off a step. Three sets are repeated 10 times. results in 95 percent smoothing of the rough por- Galvanic stimulation applied daily for 15 min- tion; normal cartilage is not harmed. From 1979 to utes and whirlpool or hot soaking at home for 15 1983, 151 chondroplasties have been done on clinic minutes 2 or 3 times daily are recommended. In patients. my view, increased circulation to the knee pro- Only part of the problem is relieved with chron- motes healing and concentrates the aspirin in the droplasty; the malalignment remains. Lateral cap- knee region instead of being distributed evenly sular retinacular release is done subcutaneously throughout the body. from the patellar tendon to the superior pole of the The running program is instituted when the patella (Fig. 6). Through arthroscopy, the align- original pain is controlled. Another prerequisite ment can be checked through the range of motion. must be a foot evaluation. It has been my experi- If the patellofemoral joint is not satisfactory, arth- ence that the excessive pronation of the feet causes roscopic release of the vastus lateralis is neces- increased irritation to the patellofemoral articula- sary. tion. Treatment is with rear foot controls or arch The surgery is performed on an outpatient basis. supports. When the patient awakes in the recovery room, 20 Jogging on the straight level surface is permit- isometric quadriceps exercises are begun and con- ted up to the point of pain. If the patient has been a tinued every hour while the patient is awake. The runner, then the distance is limited to 2 miles un- exercise, which is repeated 20 times, consists of til pain is absent for 1 week, then the distance is tightening and releasing of the quadriceps. This is, extended 1/2 mile weekly. Anaerobic conditioning in effect, a lymphatic pump. A pressure dressing is with sprinting is permitted when no pain occurs applied and the patient rewraps it twice daily for 1 when the patient jogs 2 miles. Full activity is re- week. Ambulation is allowed when the patient is sumed when Cybex II testing shows 90 percent re- fully responsive. Active range of motion is also habilitation of power, strength, and endurance. permitted. Many patellar braces are available, most with a After 2 or 3 days, isometic exercises at 0, 15, and horsehoe device attached laterally to prevent the 30 degrees for quadriceps and hamstrings are lateral subluxation of the patella.2 It is important started. The Knee Master can be used for progres- to discourage the patient from wrapping the knee sive isometric exercises, with pain or effusion tightly, because this only increases the patellofem- limiting the progression. Three to four sets of 10 oral compression force. repetitions are done daily, preferably spread The maintenance program consists of perform- throughout the day. After 1 postoperative week, 2 ing the exercises 3 times a week. Hot soaking daily courses of exercising are started. If a lateral re- is added to this program. lease without chondroplasty is done, progressive In my series, 80 percent of patients with sublux- resistance exercises are started and continued as ating patellae responded to this treatment. Con- in the conservative therapy approach. Swimming, servative management is considered to have failed bicycling, and running are also begun.

583/72 September 1985/Journal of AOA/vol. 85/no. 9 After chondroplasty, no weighted range-of-mo- ten contains a horseshoe-shaped piece of felt at- tion exercises or running is allowed for 2 months. tached superiorly that tends to take the tension off Substitution for these restrictions are bicycle rid- the patellar tendon. As a last resort, injections of ing, swimming, and running in the deep end of a corticosteroids and local anesthetics as well as sur- swimming pool. Limited arc exercises from 0-30 gery indeed may be necessary. degrees are allowed at 1 week postoperatively. Operative procedures for realignment include Quadriceps tendinitis quadricepsplasty, patellar tendon transfers, medi- The third most common cause of patellofemoral al patellar retinaculum imbrication, and bone arthralgia in this series was quadriceps tendinitis. block procedures. They may be used if recurrent In this clinic, this entity is seen in runners who dislocation of the patella occurs. pay little attention to preactivity stretching of the quadriceps mechanism. Quadriceps tendinitis is Patellofemoral tendinitis easily diagnosed when the point of maximum ten- The most common cause of disabling pain about derness is at the superior pole of the patella. The the patella in young persons is patellofemoral ten- remainder of the physical examination of the knee dinitis. In my series, there were 336 cases. is within normal limits; roentgenograms do not aid Causes for patellar tendinitis are multiple and in the diagnosis. Quadriceps tendinitis can be clas- varied, but in young persons it is often an overuse sified into phases similar to those with patellar syndrome. Patellar tendinitis is frequently re- tendinitis. ferred to as jumpers knee" in basketba11. 13 The in- Treatment of this condition consists of a thor- volvement has been classified into three phases: ough musculoskeletal examination of the lower Patients in phase 1 complain of pain only after ac- extremities. Marked tightness of the rectus fern- tivity and show no impairment of function. In oris muscle as well as the fascia lata and the ilio- phase 2 pain occurs during as well as after activ- tibial tract may be found; if so, adequate preactivity. Phase 3 involves pain with and after activity, ity stretching may relieve the patients symptoms. and also functional impairment. Evaluation of foot plant, especially in runners, re- The diagnosis is very simple. The examination veals the tendency to pronate the foot. of the knee joint yields unremarkable results ex- Treatment of quadriceps tendinitis is much the cept for exquisite pain at the inferior pole of the pa- same as for patellar tendinitis, except that injec- tella. With the patient supine, and the quadriceps tions of corticosteroids and surgery are almost nev- mechanism relaxed, the examiner places one hand er necessary. Attention should be directed to flexi- in the suprapatellar region and more or less points bility as well as endurance, as was described in the the tip of the inferior pole of the patella anteriorly. treatment for patellar tendinitis. Placement of an examining finger or a small examining instrument on the inferior pole produces Medial patellar plica exquisite tenderness. The advent of arthroscopy of the knee has shown Treatment of patellar tendinitis consists of re- that patellar pain can be caused by this medial pa- stricting the patients activities only to those that tellar plica or shelf syndrome. 2 There are three pli- do not cause pain. Physical therapy in the form of cas or synovial folds within the knee—one superior warm, moist soaks to the area 2 or 3 times a day is to the patella, one inferior, and one medial and in- recommended. If the patient performs some activ- ferior. At the time of arthroscopy, approximately ity that elicits pain, application of ice is indicated 80 percent of the knees have a medial patella plica; immediately following that activity. Ultrasound however, it is nonsymptomatic in a great majority or high-voltage galvanic stimulation is useful in of the cases. the treatment of this condition. Exercise should be Symptoms may be caused by entrapment and fi- prescribed after the muscle strength, tone, and brosis of the plica. 2 The patient complains of a flexibility in the lower extremity has been evalu- snapping sensation on the medial aspect of the ated. knee, episodes of giving way of the knee, and Quadriceps and hamstring exercises should be swelling. initiated. The gastrocnemius and soleus muscle Palpation on physical examination reveals ten- groups should be stretched. The hamstring muscu- derness medial to the patella. The results of appre- lature should also be stretched appropriately. In hension and other tests for meniscal disorders, in- the older patient, oral nonsteroidal antiinflamma- cluding McMurray and Apley tests, are within tory agents may be used for a short time. normal limits. Often, x-ray films yield no useful Multiple braces may be necessary. The brace information. consists of a device to stabilize the patella and of- Treatment of this condition includes rest until

Patellofemoral arthralgia 584/73 symptoms subside and then a gradual increase in tion to the causes that have been mentioned, as activity. Again, the important fact in rehabilita- well as appropriate changes in training and condition is flexibility and endurance exercises. A trial tioning programs, may result in complete cessa- of aspirin or other nonsteroidal anti-inflammatory tion of the symptoms while allowing patients to re- agents may be indicated. I have found bracing to main active in their chosen sport. be of no particular benefit. Surgical correction is indicated in only 5-7 per- 1. Dehaven, ICE., Dolan, W.A., and Mayer, P.J.: Chondromalacia patel- cent of cases, in my experience. Treatment of the lae in athletes. Clinical presentation and conservative management. persistently symptomatic patient consists of arth- Am J Sports Med 7:5-11, Jan-Feb 79 2. Insall, J.: Current concepts review. Patellar pain. J Bone Joint Surg roscopic resection of the plica as well as chondro- 64A:147-52, Jan 82 plasty of the medial femoral condyle if significant 3. Insall, J., Bullough, P.G., and Burstein, A.H.: Proximal "tube" rea- chondromalacia has developed because of pressure lignment of the patella for chondromalacia patellae. Clin Orthop Ref Res of the plica on the femoral condyle with flexion and 144:63-9, Oct 79 4. Cailliet, R.: Knee pain and disability. Ed. 2. F.A. Davis and Co., extension of the knee. Philadelphia, 1983 5. Outerbridge, R.E., and Dunlop, JA: The problem of chondromalacia Summary patellae. Clin Orthop 110:177-96, Jul-Aug 75 6. Morrison, J.B.: The mechanics of the knee joint in relation to normal Patellofemoral arthralgia may result from habit- walking. J Biochem 3:51-61, 1970 ual overloading caused by activity. 2 This syn- 7. Reilly, D.T., and Martens, M.: Experimental analysis of the quadriceps muscle force and patellofemoral joint reaction force for various ac- drome often develops in young patients who de- tivities. Acta Orthop Scand 43:126-37, 1972 scribe abnormal conditioning and training 8. Kettelkamp, D.B.: Biomechanics of the knee. Normal and abnormal. programs. Examples are youngsters who get in- Instructional course lecture. Am Acad Orthopaed Surg, Dallas, Texas, 1974 volved in athletics for the first time or who begin a 9. Gruber, M.A.: The conservative treatment of chondromalacia patel- sports season with excessive cross-country run- lae. Orthop Clin North Am 10:105-15, Jan 79 ning, cheerleading, tennis playing, and so forth. 10. Insall, J.: "Chondromalacia patellae." Patellar malalignment syndrome. Orthop Clin North Am 10:117-27, Jan 79 The patients report a history of pain around and 11. Insall, J Falvo, K.A., and Wise, D.W.: Chondromalacia patellae. A under the patella, which worsens with stair climb- prospective study. J Bone Joint Surg 58A:1-8, Jan 76 ing or after sitting for long periods. Many of the 12. American Academy of Orthopaedic Surgeons Proceedings. Sympo- sium. Early degenerative arthritis of the knee. (Chrisman, 0.D.) J Bone symptoms are brought on after overuse. Joint Surg 51A:1027, Jul 69 Palpation of the borders of the patella usually 13. Blazina, M.E., et al.: Jumpers knee. Orthop Clin North Am 4:665- elicits tenderness. There is pain with extension of 78, Jul 73 the knee from the flexed position against resistance. Minimal patellar crepitus may be present. Accepted for publication in October 1983. Updating, as neces- Symptoms of locking, catching, clicking, or giving sary, has been done by the author. way ordinarily are absent. Evaluation of the muscle strength, flexibility, and endurance of the low- Dr. Hunter is board-certified in orthopedics, is president of the er extremities is indicated. Frequently, abnormal Mid-States Orthopedic Sports Medicine Clinics of America, Ltd., and is president of the St. Louis Orthopedic Sports Medi- foot plant may precipitate or aggravate symptoms. cine Clinic. Treatment of this syndrome consisits of rest Dr. Hunter, Suite 311, 14377 Woodlake Drive, Highway 40 and with limitation of activity. However, strict atten- Woods Mill Road, Chesterfield, Missouri 63017.

585/74 September 1986/Journal of AOA/vol. 85/no. 9