Introduction

Patellar instability is an umbrella term for patellar subluxation and dislocation.₁ It may occur as a result of: - weakness of the medial muscles such as the VMO; torn medial soft tissues such as the medial patellofemoral ligament (MPFL); tight lateral soft tissues such as the lateral retinaculum, vastus lateralis or the iliotibial band; or patella alta.₂,₃

The MPFL is the primary stabiliser of the patella, limiting lateral patellar translation and providing between 53 and 67% of the medial soft tissue restraint.₄,₅,₆,₇ It lies deep to the vastus medialis muscle, attaching from the posterior part of the medial epicondyle, to the superomedial patella, the under-surface of the vastus medialis, and the quadriceps tendon.₈

In the majority of patellar dislocations the MPFL is disrupted.₉,₁₀,₁₁ The re-dislocation rate of primary patellar dislocations managed non-operatively is between 15 to 44%.₇,₁₂,₁₃,₁₄ Accordingly, several authors have suggested that repair or reconstruction of the MPFL may reduce this high incidence of recurrent dislocation.₇,₁₅,₁₆

Various different methods of reconstructing the MPFL have been described, harvesting different soft tissues to reconstruct the ligament. These have included using the adductor magnus,₁₇,₁₈ quadriceps tendon₇,₁₅and semitendinosus.₁₉,₂₀,₂₁

Following a review of the literature, no detailed descriptions were identified on how to rehabilitate patients following a MPFL reconstruction. Accordingly, the purpose of this paper is to present such a physiotherapy protocol (Table 1). To illustrate this, a patient who underwent a MPFL reconstruction treated using this programme is presented. The patient was selected as she was operated on over 12 months ago. This allowed us to present her treatment progression and outcomes over a prolonged period. Signed informed consent was obtained from the patient to present her management in this case study.

Table 1: A rehabilitation protocol for patients following a medial patellofemoral ligament reconstruction

Figure 1

The Patient

The patient was a 24 year old woman who worked in the catering industry. She had a 10 year history or bilateral recurrent patellar dislocation; her left knee was subjectively reported as worse than her right. She reported that her knee functionally limited her, and that she felt that her patella would “pop out of place” during everyday activities such as getting into a car or dancing. She was unable to run.

The patient was referred by her General Practitioner to a specialist orthopaedic knee surgeon. At her initial consultation with the surgeon, she presented with full range of movement to both knees, but bilateral positive apprehension test and J-shaped tracking to both patella. A computed tomography (CT) scan was undertaken of her left knee, reporting a shallow trochlear groove with lateral patella tracking. The surgeon recommended a left MPFL reconstruction.

Surgical Procedure

A MPFL reconstruction was performed using a semitendinosis free graft. A longitudinal incision was made over the patella. The patella was accessed, and a bony tunnel was made in its upper medial border. The graft was passed through this, tunnelled through the second layer of the medial retinaculum and “whip-stitched” together. A second incision was made over the medial femoral condyle. A pit was formed at the medial femoral condyle, at the origin of the MPFL, and the graft was held in this femoral pit using a screw. The knee was then assessed arthroscopically to ensure that the patella was lying correctly within the femoral trochlear and that there was no instability on flexion and extension of the knee. The incisions were closed and the knee was dressed in gauze, wool and crepe bandage. Figure 1 illustrates the 2 incisions required for graft fixation from the patella, to the medial femoral condyle.

Figure 1: The MPFL Reconstruction Incisions.

Figure 2

The post-operative instructions permitted knee range of movement exercises after 2 hours post-operatively, to mobilise full weight-bearing and out-patient physiotherapy.

In-Patient Physiotherapy

After having her operation in the morning, the patient was seen by an orthopaedic physiotherapist that afternoon. The patient reported that her knee was painful. After being administered oral analgesia by the nursing staff, she was taught an exercise programme including: unlimited range active and active assisted knee flexion and extension exercises; static and inner range quadriceps; and ankle dorsiflexion and plantarflexion exercises. She was encouraged to perform these as often as possible, and continue on discharge at home. The patient's knee range of movement was minimal, from approximately 0 to 40°, limited by pain.

The patient was instructed on how to begin walking using 2 elbow crutches. She was encouraged to weight-bear through her left knee as much as possible; this was however, limited by pain. A reciprocal gait pattern was taught and she could mobilise in excess of 20 metres. She was shown how to, and safely negotiated stairs using her crutches.

Out-patient physiotherapy was arranged to commence as soon as possible, and the patient was discharged home the day after her operation.

Out-Patient Physiotherapy

Following the protocol presented in Table 1, a full musculoskeletal assessment was performed on the patient's initial out-patient appointment. Through this, the patient reported a constant ache to the anterior aspect of her knee, limiting her knee range of movement to minus 55° extension and to 60° flexion when assessed using a long-arm goniometer. Significant generalised quadriceps wasting was noted. She reported that the pain was disturbing her sleep up to 4 times each night, and to relieve this, she was sleeping with a pillow underneath her knee. She was taking up to 6 codeine based painkillers per day to help manage her symptoms. She had not continued the post-operative exercises she was shown in hospital. The patient was still walking with the aid of 2 elbow crutches, toe-touch weight-being due to pain.

The patient was seen on an outpatient basis on 8 occasions over 4 weeks. Initial outpatient treatment included advice regarding self-management of pain using heat,₂₂ mobilisations-with-movements using lateral glides into flexion,₂₃ and a home exercise programme. This included active assisted and active knee flexion and extension exercises, straight-leg raises and static quadriceps activities. The objective of these were to restore full active and passive range of motion, regain good quadriceps contraction and control, and full early weight-bearing as soon as possible.₂₄ In an attempt not to unduly load the patellofemoral joint, and to encourage functional movement, there was a bias towards closed-chain activities.₂₅

Although by the fourth treatment session the patient was progressing well, she still had limited knee extension at minus 10°, and only 110° flexion limited by pain. Accordingly, she was transferred to our Hydrotherapy class where the heat of the water, in addition to the therapeutic effects of exercising with or against buoyancy,₂₆ were introduced to improve the patient's pain and range of movement.

She attended her hydrotherapy classes 4 times over 2 weeks. Activities performed included further gait-re-education against the resistance of water, squat and lunge exercises, resisted and assisted knee flexion activities. The patient continued with her home exercises on non-gym days, and was discharged from the Physiotherapy Department 3 months post-operatively.

Outcome

Following this programme, when reviewed 6 months post-operatively, the patient reported that her left knee felt stronger, with no recurrent patellar dislocations, and was completely satisfied with her surgery. She had increased confidence in the use of her knee, full range of motion, and had returned to her normal home and work activities. She had regained full pain-free range of movement and had good quadriceps control. Her Kujala score improved from 59 to 81.₂₇ These outcomes were maintained at a 12 months post-operatively review. She had a MPFL reconstruction to her right knee the following year.

Discussion

This paper has presented a physiotherapy rehabilitation protocol for patients following a MPFL reconstruction, illustrated using a case-study. This patient reported a successful outcome with the resolution of her patellar instability. Such a successful outcome mirrors the findings from previously presented case-series.₁₇,₁₈,₁₉,20,₂₈,₂₉

This paper presents the rehabilitation of a specific individual. As with all rehabilitation programmes, the patient's management should be tailor-made, to meet both patient's and physiotherapist's objectives.₃₀For example, the patient presented in this case was not sports orientated. Accordingly, the sports-related rehabilitation detailed in the protocol was not necessary. Nonetheless, MPFL reconstruction patients do participate in sports post-operatively,₁₉ and this should be assessed and incorporated into the rehabilitation of both amateur and elite sports-people who undergo a MPFL reconstruction. Therefore, the rehabilitation protocol described is recommended to simply guide physiotherapy during their clinical decision-making.

The case presented in this paper exhibited limited knee range of movement and significant pain control issues when she attended her initial out-patient appointment. Subsequent cases treated in our department have presented with similar problems during this early phase in their rehabilitation. In response to this, it is critical that patients who follow this accelerate rehabilitation programme require early out-patient physiotherapy, preferably within the first few days following their in-patient discharge. We feel that this is paramount to help prevent and limit early restriction in range of movement and pain issues which was presented in this case report.

The protocol described does not immobilise knees, and encourages the return to functional activities as soon as possible. Accordingly, patients are encouraged to exercise and strengthen muscles, particularly the quadriceps, from the day of their operation. By not immobilising the knee, contrary to other author's suggestions,₁₇,₁₈,₁₉,₂₈ the likelihood of the detrimental effects of immobilisation such as joint stiffness, articular degeneration, muscle atrophy and can be minimised.₃₁,₃₂,₃₃ Similarly, weight-bearing is not restricted, unlike previously described post-operative instructions.₁₈,₁₉,₂₈Further study is indicated to investigate whether bracing or weight-bearing status can influence outcomes such as quadriceps strength, function, patient satisfaction and post-operative complications after a MPFL reconstruction.

Prolonged recurrent patellar instability is the most frequently citied indication for this procedure.₂₁,₃₄Accordingly, patients become apprehensive about the stability of their knees. This can be a significant factor, and providing reassurance and incorporating activities which the patients had previously avoided, can be an important part of their rehabilitation.

Conclusion

This single-case study has described and presented the physiotherapy management of a patient following a MPFL reconstruction. The early objectives after this procedure are to regaining full range of motion and strength. Following this, patients are rehabilitated further to optimise their outcome, and to return to daily and sporting activities without fear of recurrent dislocation. It is intended that a case-series of patients rehabilitated using this protocol shall be presented as a future publication, to assess the outcomes of this accelerated rehabilitation programme for a larger number of patients. Further research is suggested to determine the optimal rehabilitation of patients following a MPFL reconstruction.

Ethical Approval: Signed consent was obtained from the patient presented in this case study.

Correspondence to

Mr T O Smith Orthopaedic Physiotherapy Research Unit Physiotherapy Department - Out-Patients East Norfolk and Norwich University Hospital Colney Lane Norwich Norfolk, NR4 7UY Tele: 01603 286990 Fax Number: 01603 287369 Email Address: toby.smith@nnuh.nhs.uk