This paper, published in 1999, discusses 'open' surgery for arthrofibrosis as opposed to 'arthroscopic' surgery (that is surgery with an incision, exposing the inside of the joint as opposed to keyhole surgery).
Although only a small number of patients were presented (8 knees, 8 patients), it is nonetheless interesting as they all had extensive arthrofibrosis with severely restricted motion. The fibrous process had involved both the structures within the knee joint and also structures outside the joint cavity itself. The average total range of motion was only 62.5 degrees before surgery, with an average loss of extension of 18.8 degrees. Average flexion was only 81 degrees.
The authors begin by pointing out that arthrofibrosis represents a 'spectrum' of abnormalities, leading to abnormal joint movement, poor function and joint surface damage. The abnormal process can involve the inside of the joint ('intra-articular'), the tissues imediately around the joint ('peri-articular') and the tissues properly outside the joint ('extra-articular').
Most patients, they say, even those with severe problems, will respond to physical therapy, manipulation or arthroscopic release. But there is a small subset of patients where non-operative and arthroscopic management fails to restore motion - and this series of eight patients fall into that group. Peri-articular and extra-articular scarring may even render arthroscopy impossible. Contractures outside the joint or poorly positioned cruciate ligament grafts may mean that the arthroscopic release on its own has no real effect on the range of motion.
The patient group
The patients averaged 29 years (range 19-43), and there were four men and four women. In all but one an ACL (anterior cruciate ligament) tear was the original injury and in these the ligament reconstruction had been undertaken within a month after injury. The surgery to release the arthrofibrosis was undertaken at an average of 12.3 months (range 6-19 months). All had significant loss of motion, which was interfering with their lives. In seven of the patients arthroscopic surgery had failed to restore function, and in the eight patient arthroscopic surgery had been aborted as there was 'myositis ossificans in the vastus lateralis muscle', that is one of the parts of the quadriceps muscle was undergoing cellular change and effectively trying to turn into bone.
All patients had epidural catheters inserted to give anaesthesia (fentanyl citrate and mepivacaine) during the surgery and these were left in place afterwards to assist with pain relief and allowing more intensive physical therapy in the immediate postop period. A tourniquet was used during surgery.
The surgery itself differed depending upon whether flexion loss or extension loss predominated:
- flexion loss - release of contractures of the knee capsule, removal of scarring inside the joint cavity, and removal of scarring around the 'extensor mechanism' (that is, related to the smooth function of the quads muscle and the kneecap and its tendon)
- extension loss - release of scarring in the front of the knee around the patellar tendon, widening of the notch in which the cruciates sit, and release of scarring in the posterior capsule
Usually the skin incision (cut) was made in the midline, and the surgeon dissected the underlying tissues to reveal the patella and its tendon below. Then access to the deeper tissues and the joint cavity was gained by retracting the tissues and making a deeper cut on the medial (inner) aspect of the patella and its tendon. Briefly the procedures included -
- Medial Release -
This is a dissection of the soft tissues on the inner aspect of the knee right down to the tibia bone, lifting up the fibrous lining of the bone, and going under it, and releasing the deep part of the medial collateral ligament and the semimembranosus tendon. This has the effect of freeing the tibia from the scarring and allowing extension.
Scar tissue was cut away to release the medial and lateral gutters on either side of the tibia, and the joint capsule was freed at the front of the knee.
- Extensor Mechanism Release and Patellar Eversion
All eight patients were found to have scar tissue in the infrapatellar fat pad - the fatty lump of cushioning tissue which fills the space between the kneecap and the cruciate ligaments. This scar tissue was cut away and then the patellar tendon freed from the tibia bone below, taking care not to damage its tibial tubercle attachment.
- A lateral retinacular release -
cutting the normal supportive tissues on the lateral (outer) side of the patella - allowed the patella to be flipped over, thereby giving a wider view into the knee joint itself. Where this was too difficult due to the scar tissue the incision was instead simply extended and scar tissue cut away until the patella could be flipped over. Once the surgeon could see into the joint, scar tissue was cut away all along the length of the extensor mechanism (quads, quads tendon, patella, patellar tendon), while intermittent checks were made to see how the patella tracked when the knee was bent and straightened.
- Ligament and Capsular Releases -
Once all these tissues had been released, the surgeon could then assess how much range of motion had been gained, and how many degrees loss still remained.
If the ACL graft was at that stage considered to be mal-positioned and contributing to the limitation of motion, the graft itself was simply cut out and all the 'hardware' (screws and other fixation devices) removed - to remain so until a later date when the ACL graft could be properly redone.
The tibia was then pulled forward and the back of the knee explored to see what structures in this region were contributing to the motion loss. If the capsule was contracted, these contractures were released and any scar tisue cut away from the capsue. Any dense scarring at the back of the femur was peeled right off the bone, leaving it bare, but taking care not to damage the collateral ligaments. If any PCL graft was causing a problem, the PCL too was cut right out.
Range of motion continued to be intermittently checked, and if flexion was still limited the posterior capsule was lifted up or scraped off off the femur at the back of the knee, again right down to bare bone.
The tourniquet was then deflated, and all bleeding vessels sealed with cautery (burned). This was considered an important step as bleeding into the joint after surgery ('haemarthrosis') causes pain and can trigger all the inflammation all over again.
- Steroids - The patients were all put onto cortisone for 48 hours after surgery.
- RICE Regime (rest, ice, compression, elevation - Icing (cryotherapy) was instigated to decrease swelling and pain. Compressive dressings were used to keep swelling down.
- CPM (continuous passive motion)- CPM (0-60 degrees, 6 hours a day) was begun on the day of surgery. 90 degrees was the flexion desired.
- Extension bracing - An extension brace was applied at night to knee the knee in extension.
- Physical Therapy - Active and passive motion exercises were begun immediately after surgery, and sessions continued twice a day. Patients were taught exercises to do between sessions. Early quads muscle activity was encouraged. Toe-touch weightbearing was encouraged and full eight-bearing expected by two weeks. Patients were discharged only if they had -
- full extension
- flexion to 60 degrees
- good pain control
- competence with the crutches
- competence getting in and out of chairs and cars
- an understanding of their exercise regime and how to manage the braces
On discharge they were given a home exercise programme but also attended outpatient physical therapy sessions, with a graduated programme over 12 weeks emphasising flexibility. At the end of surgery patients had full motion, but the authors noted that immediately after surgery some of this was lost, although most improved by the first outpatient session.
The authors felt this study was encouraging, with improvements gained in both motion and function, but they noted that only one patient was able to return to her original functional level. They were very concerned that patients showed joint surface degeneration, particularly in the patellofemoral joint. They felt that aggressive passive exercise and manipulations had probably contributed to this, but that a big element was that there was progressive patellar tendon shortening (patella infera).
The authors stress that such open surgery should not be done except as a 'salvage' procedure, and that arthroscopic surgery should always be tried first and open surgery resorted to only if the arthroscopy does not restore range of motion.