Dissecting a popliteal cyst after failed unicompartmental knee arthroplasty

Outcomes After Arthroscopic Evaluation of Patients With Painful Medial Unicompartmental Knee Arthroplasty

BACKGROUND

Persistent pain after medial unicompartmental knee arthroplasty (UKA) is a prevailing reason for revision to total knee arthroplasty (TKA). Many of these pathologies can be addressed arthroscopically. The purpose of this study is to examine the outcomes of patients who undergo an arthroscopy for any reason after medial UKA.

METHODS

A query of our practice registry revealed 58 patients who had undergone medial UKA between October 2003 and June 2015 with subsequent arthroscopy. Mean interval from medial UKA to arthroscopy was 22 months (range 1-101 months). Indications for arthroscopy were acute anterior cruciate ligament tear (1), arthrofibrosis (7), synovitis (12), recurrent hemarthrosis (2), lateral compartment degeneration including isolated lateral meniscus tears (11), and loose cement fragments (25).

RESULTS

Mean follow-up after arthroscopy was 49 months (range 1-143 months). Twelve patients have been revised from UKA to TKA. Relative risk of revision after arthroscopy for lateral compartment degeneration was 4.27 (6 of 11; 55%; P = .002) and for retrieval of loose cement fragments was 0.05 (0 of 25; 0%; P = .03). Relative risk for revision after arthroscopy for anterior cruciate ligament tear, arthrofibrosis, synovitis, or recurrent hemarthrosis did not meet clinical significance secondary to the low number of patients in these categories.

CONCLUSION

The results of this study suggest that arthroscopic retrieval of cement fragments does not compromise UKA longevity. However, arthroscopy for lateral compartment degradation after UKA, while not the cause of revision, appears to be an ineffective treatment and predicts a high risk of revision to TKA regardless of its relative radiographic insignificance.

[Arthroscopic procedure for Baker's cysts : surgical technique. Video article]

BACKGROUND

Baker's cysts are related to increased intra-articular pressure. The causes may be inflammatory, degenerative or traumatic disorders. Owing to the increased intra-articular pressure a cyst protrudes between the semimembranosus and the medial gastrocnemius tendons. The traditional treatment for a Baker's cyst is open resection. As an alternative, an arthroscopic procedure can be performed, which is demonstrated by the video on surgical technique that accompanies this short report.

SURGICAL TECHNIQUE

From the anterolateral portal the arthroscope is advanced through the intercondylar notch (below the posterior cruciate ligament) to the posteromedial recess. Under visual control, a posteromedial portal is created followed by identification of the capsular fold separating the cyst from the joint cavity. This fold (valvular mechanism) is resected with a shaver from the posteromedial portal until a large enough connection exists between the joint and the cyst (cyst decompression). After the decompression, the arthroscope is inserted from the posteromedial portal directly into the cyst cavity. Subsequently, the inner wall of the cyst is removed with the shaver via an additional far posterior cystic portal. It is obligatory to treat the associated intra-articular pathological condition. In our video a medial meniscal lesion is treated with partial meniscectomy.

Subcalcaneal bursitis with plantar fasciitis treated by arthroscopy

We report the successful arthroscopic treatment of a case of subcalcaneal bursitis with plantar fasciitis. To our knowledge, this is the first report on arthroscopic excision of a subcalcaneal bursa. Right heel pain developed in a 50-year-old woman, without any obvious cause. She reported that the heel pain occurred immediately after waking and that the heel ached when she walked. Magnetic resonance imaging showed an extra-articular, homogeneous, high-intensity lesion in the fat pad adjacent to the calcaneal tubercle on T2-weighted sagittal and coronal images and thickening of the plantar fascia on T2-weighted sagittal images. A diagnosis of a recalcitrant subcalcaneal bursitis with plantar fasciitis was made, and surgery was performed. The arthroscope was placed between the calcaneus and the plantar fascia. With the surgeon viewing from the lateral portal and working from the medial portal, the dorsal surface of the degenerative plantar fascia was debrided and the medial half of the plantar fascia was released, followed by debridement of the subcalcaneal bursal cavity through the incised plantar fascia. Full weight bearing and gait were allowed immediately after the operation. At the latest follow-up, the patient had achieved complete resolution of heel pain without a recurrence of the mass, confirmed by magnetic resonance imaging.

Compartment syndrome and popliteal vascular injury complicating unicompartmental knee arthroplasty

Popliteal vascular injury and the compartment syndrome of the leg are rare but important complications of knee arthroplasties. Early diagnosis and treatment are of paramount importance in preventing the devastating complications of these conditions. To our knowledge, these complications have not been reported previously after unicompartmental knee arthroplasty in the literature. Low level of suspicion may delay the diagnosis, as popliteal vascular injury and compartment syndrome are not well recognized as possible complications of unicompartmental knee arthroplasty.