**3.5**

Before 1990s, post-TKR patellar clunk syndromes were managed by open arthrotomy and excision of the offending fibrous nodule and adhesion. Although it has been effective in treating the symptoms of "clunk" and had successful results without recurrence, there are morbidities associated with this approach such as wound complication and delay in regaining range of motion. The requirement of postoperative analgesics for pain control is higher, and the length of hospitalization is often prolonged.

Advantages of using arthroscopy in treating patellar clunk syndrome included clear visualization of the pathology and few associated complications. The recovery period required for patients to regain full range of motion and normal activity is shorter. However, the synovitis itself could easily be removed with a motorized shaver. On the technical side, the supra-patellar joint space and the medial and lateral gutters are often contracted.

Arthroscopic debridement is an accepted treatment option for both patellar clunk syndrome and synovial hyperplasia; however, there is a paucity of functional outcome data in the literature, especially with respect to synovial hyperplasia.

Adhesions around the knee are usually debribed, first to make room for instrument insertion and then for the subsequent debridement of the dense fibrous nodules. Instrument insertion into the suprapatellar space and parapatellar gutters could therefore avoid causing iatrogenic damage to the surface of the prosthesis. The fibrous nodules are normally tough. Punch forceps and scissors are needed to shred them before the motorized shaver could debride them effectively. Care must be taken to avoid damaging the prosthesis components, as the potential risk of increasing the rate of wear of the prosthesis is theoretically possible.

Takahashi et al. classified the soft tissue impingement under patella after total knee arthroplasty into 3 categories [19]: Patella Clunk Syndrome


Arthroscopic Classification (Thorpe & Bocell): Tethered Patella Syndrome


Before 1990s, post-TKR patellar clunk syndromes were managed by open arthrotomy and excision of the offending fibrous nodule and adhesion. Although it has been effective in treating the symptoms of "clunk" and had successful results without recurrence, there are morbidities associated with this approach such as wound complication and delay in regaining range of motion. The requirement of postoperative analgesics for pain control is

Advantages of using arthroscopy in treating patellar clunk syndrome included clear visualization of the pathology and few associated complications. The recovery period required for patients to regain full range of motion and normal activity is shorter. However, the synovitis itself could easily be removed with a motorized shaver. On the technical side, the supra-patellar joint space and the medial and lateral gutters are often

Arthroscopic debridement is an accepted treatment option for both patellar clunk syndrome and synovial hyperplasia; however, there is a paucity of functional outcome data in the

Adhesions around the knee are usually debribed, first to make room for instrument insertion and then for the subsequent debridement of the dense fibrous nodules. Instrument insertion into the suprapatellar space and parapatellar gutters could therefore avoid causing iatrogenic damage to the surface of the prosthesis. The fibrous nodules are normally tough. Punch forceps and scissors are needed to shred them before the motorized shaver could debride them effectively. Care must be taken to avoid damaging the prosthesis components, as the potential risk of increasing the rate of wear of the

Takahashi et al. classified the soft tissue impingement under patella after total knee

Type I Fibrous firm nodule just proximal to the patella button without the other

Type II Impinging hypertrophic synovitis, generalized hypertrophic synovitis

Type III Combination of a fibrous nodule proximal to the patella button and

Type I Transverse fibrous band at the junction between the patella and quadriceps

higher, and the length of hospitalization is often prolonged.

literature, especially with respect to synovial hyperplasia.

arthroplasty into 3 categories [19]: Patella Clunk Syndrome

without fibrous nodule

fibrous tissues causing the impingement

generalized hypertrophic synovitis

Type II Longitudinal band in the lateral parapatellar gutter

Arthroscopic Classification (Thorpe & Bocell): Tethered Patella Syndrome

prosthesis is theoretically possible.

tendon

Type III Band in the infrapatellar region

**3.5** 

contracted.

Fig. 10. Arthroscopic sequence of resection of the nodule.

Fig. 11. Appearance after resection of the nodule

Arthroscopy Following Total Knee Replacement 251

study, claims 75% success of pain relief after arthroscopic debridement of impinged PCL

Literature suggests that on few occasions' additional portals to assist adequate visualization of the posterior compartments and also to avoid iatrogenic damage to prosthetic component in a struggle to see at the back of total knee replacement is required. Although Diduch describes adequate view with standard anterior portals, there are suggestions of posteromedial and posterolateral portals in addition to the standard anterior ones (Landsiedl). Before attempting to see into posterior compartment, it is advised to release or resect any adhesions, which enables complete inspection of the anterior compartment of the knee joint, including soft tissue impingements, evaluation of

It is recommended, through the standard anteromedial portal, a wide semicircular notchplasty should be performed (diameter of about 8 to 10 mm) in the posterior superolateral region of the notch just above the posterior condyle of the femoral component, to allow entrance of the arthroscope into the posterolateral compartment from the anteromedial portal. Due to the semicircular shape of the notchplasty, the arthroscope and the resecting instruments are mobile and otherwise inaccessible areas can be inspected and treated. A 1.2-mm can be inserted through posterolateral portal into the joint under arthroscopic control. A posterolateral portal is established with a stab incision. After blunt preparation down to the capsule, a working cannula is inserted using a sharp trocar for penetration parallel to the cannula to avoid slipping along the posterolateral capsule, frequently happens with blunt trocars. This usually provides an adequate view of the posterolateral compartment. Impingement of degenerated tissue in flexion can be seen much better from this portal than from the trans-fossa approach. Similarly, posteromedial portal can be established to work your way around the PCL stump. After resection of the PCL stump and its posterior synovial sheath, the posteromedial compartment can be inspected

Technical problems lay in mirror images with problems in orientation, and the possibility of damaging the components by manipulation of the optic sheet or motorized instruments. The key points are the exact location of the portals and a smooth introduction of the trocar. For orientation, the use of a probe is mandatory to distinguish between reality and mirror image. The use of additional portals helps to avoid damaging the prosthesis components, especially by using motorized shavers and visualizing the tracing behavior of the patella. Alterations to the surface of cobalt-chromium femoral components can occur during arthroscopy with stainless-steel cannulae. Damage and degradation of the articulating surfaces of a total knee replacement have been associated with release of wear debris. There is a correlation between surface roughness of cobalt-chromium femoral components and polyethylene wear of the tibial component. In addition, studies have shown extensive foreign-body giant-cell reactions to polyethylene particles and synovial membrane reactions to loose cobalt chromium particles. To avoid this Raab recommends the use of plastic

stump in total knee replacement patients.

the inlays and tracking of the patella.

**4.6 Technical challenges** 

cannulae instead of metallic ones.

completely using the anteromedial or posterolateral portals.

**4.5 Arthroscopy technique** 
