A 54 year female reported to the physiotherapy department with complaints of persistent pain at left knee, with more than two month history of stiffness and functional disability. Area of pain described by the patient was anterior and medial aspect of the knee, with characteristic of pain as burning and induced by any mechanical stimulation, including sensory stimulation from clothing.
The patient had a history of sudden onset of anterior knee pain & locking of left knee while getting up a squatting position, two & half months ago. This was followed by extreme limitation of movement and pain during activity. The patient had undergone arthroscopy two days after the inciting event. Medial plical resection was done through arthroscopy. Further reports had revealed synovial hypertrophy in supra-patellar pouch along with degeneration of medial and lateral patellar facets. One month post arthroscopy, patient had history of painful effusion of the knee. Aspiration had been carried out with 15cc of synovial fluid aspirated.
On observation the patient presented with limp while walking, flexed attitude of the knee along with trophic changes of dry and scaly skin. Skin around the affected area was warm but dry, with edema (non pitting nature) around the anterior aspect of the knee. There was allodynic & hyperalgesic pain response to any palpation on anterior and medial aspect of the knee. Patient revealed global patellar mobility loss with restriction of tibiofemoral joint on active and passive movement examination. Muscle power was reduced to grade 3+, on manual muscle testing (MMT), in the available range. Functional ability of the patient was restricted to a larger extent, such that patient had difficulty in ambulation, managing stairs and most of house hold activities were compromised. Patient’s daily activities were restricted to indoors only, as patient demonstrated fear avoidance behaviour.
Pressure algometric measurements were carried out for quantification of pain response. Four areas were selected for measurement of algometric readings – supra patellar (SP), medial femoral condyle (MC), centre of patella (PT) & infrapatellar – just superior to tibial tuberosity (IP). The areas were chosen based on area of complaint. Response from three spots from each area was recorded and an average considered. Pain response was recorded as P1 (pressure at onset of pain) & P2 (pressure at maximum pain). Maximum pain response was recorded over supra patellar area followed by infrapatellar, patella and finally by medial femoral condyle (Figure 1). Goniometric measurements of knee recorded an available active range of 20°; from 10° flexion to 30° flexion. Knee outcome survey activities of daily living scale was used for assessing functional limitations of the patient. The scale considers various limitations encountered by the patient in last 1 or 2 days, while performing usual daily activities. It consists of set of 10 questions for with patient is asked to mark the appropriate response. The scale is a reliable, valid and responsive instrument for the assessment of functional limitations that result from wide variety of pathological disorders & impairments of knee [9]. The patient was unable to kneel, squat & sit with knees bent. Severe restriction was recorded while descending from stairs. Ability to rise from chair required use of hands. Walking, associated with limp, and standing ability was less than 10 min.
The patient met the criteria for establishing a probable diagnosis of CRPS knee (type I), after ruling out any post arthroscopic infections, vascular disorders, stress fracture, referred pain, any peripheral neuropathy and any metabolic or inflammatory disorders. In our study the diagnosis was made on clinical grounds using accepted diagnostic criteria [10]. A working hypothesis of CRPS (type I) was established given the reason that patient demonstrated disproportionate pain, hyperalgesia, edema, temperature asymmetry, skin changes, movement loss & absence of major nerve injury.
The patient was managed for a period of four sessions, once per day for 45 min, using graded desensitization therapy, TENS & graded gentle mobilization besides the home program that was taught to the patient.
Transcutaneous electrical stimulation (TENS) was the first modality of choice. TENS was applied using a single channel with electrodes placed at the periphery of the area of complaint i.e. medial condyle, suprapatellar area, lateral border of patella & infrapatellar. Burst TENS was employed using a portable TENS device with a pulse width 100μs, pulse rate of 70 Hz and intensity comfortable for the patient for duration of 20 minutes/day.
Graded desensitization for hyperalgesia was started on the first day of treatment. It included sensory stimulation using various textures. The desensitization was started around the periphery of the lesion with smooth surface first, slowly progressing to a coarser surface and towards the centre of the area of complaint. The desensitization therapy lasted for around 20 minutes each session. Patient was taught and instructed to use desensitization as a home program at least 2 – 3 times a day for 15 minutes duration each. The patient responded well to the treatment and showed good response in terms of tolerance of sensory stimulation.
Gentle mobilization of patella in all directions using Maitland’s grades of oscillatory mobilisation was used [11]. Grade I on 1st day was employed, which progressed to higher grades (grade II & grade III on 2nd & 4th day). Gentle mobilization of patella was also taught to patient, with amplitude as patient tolerated, to be used as home program at least twice a day. Along with patellar mobilization active mobilization of knee joint was performed on every session with 3 – 5 sets and 20 repetitions/set. The patient was instructed to concentrate on gaining maximum ROM with full knee extension. Enough rest time given in between the treatment repetitions to avoid any unnecessary fatigue.
A mirror visual feedback, using the unaffected extremity, was employed for gaining maximum out of active knee mobilization. The patient was instructed to move the affected extremity in relation to unaffected, mirroring its motion both during flexion and extension. The effect of this feedback is based on the finding that visual input from moving, unaffected limb re-establishes pain free relationship between sensory feedback & motor execution of upper limb [12]. Classically this form of treatment is employed using a mirror; we preferred using patient affected extremity itself, as we aimed at gaining maximum ROM.
Thermotherapy was attempted initially, but patient could not tolerate any form of superficial heating modality well. Patient showed a marked improvement in range of movement (ROM), hypersensitivity, pain and function. The ROM improved from total of 30° pretreatment to 80° after 4 days of treatment. Post 4 days treatment goniometric measurement revealed an active range of 20° flexion to 100° flexion in open chain. Algometric pain responses improved considerably in increased threshold for both P1 & P2. The improvement was seen in all 4 areas with maximum improvement seen in infrapatellar area followed by suprapatellar and medial femoral condylar area. The patellar area pain response improved to the least (Figure 2 and 3).
After 4th day the patient was referred to local physiotherapy OPD for further treatment and was instructed to continue the home program already explained.