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Good balance is essential for the effective pain-free and durable function of a TKA. It is important to recognize that knee balance is not simply a function of soft-tissue balance. Balance of the knee joint following TKA is influenced by, 1. Component size, level and alignment and related bone surgery 2. Articular geometry 3. Soft-tissue envelope ERRORS OF KNEE BALANCE There are innumerable ways to commit errors of knee balancing. | CONCEPTS UNDERLINING BALANCING IN TKA Wui K. Chung FRACS Good balance is essential for the effective pain-free and durable function of a TKA. It is important to recognize that knee balance is not simply a function of soft-tissue balance. Balance of the knee joint following TKA is influenced by 1. Component size level and alignment and related bone surgery 2. Articular geometry 3. Soft-tissue envelope ERRORS OF KNEE BALANCE There are innumerable ways to commit errors of knee balancing. Major errors may result in loss of motion pain instability loosening or early wear of the prosthesis. The main categories of errors are Component malalignment Errors of patellar resurfacing Alteration of joint level Errors of soft-tissue balancing Errors of Flexion-Extension space balancing Less severe errors may result in more subtle problems such as recurrent effusion post-activity aches and less than satisfactory range of motion. Some common errors of knee balancing are less recognized eg. Extension loss - occurs frequently. To avoid this error the surgeon should aim to obtain 3 degrees of extension with the components in place. If only zero degrees of extension is obtained during surgery there is a strong likelihood that a flexion deformity will ensue. Postoperative pain resulting in quadriceps inhibition and hamstring spasm if unattended will also result in development of a fixed flexion contracture Flexion laxity - is a common error that is not recognized adequately by many practitioners. Laxity in extension is readily appreciated as patients with the problem suffer obvious instability. Mild flexion laxity may not cause instability symptoms but causes recurrent activity-related effusion post-activity pains and increased wear rate. Flexion laxity often results from over-zealous soft-tissue release. Over-zealous soft-tissue release - in the effort to fully expose the knee joint during surgery surgeons often perform excessive soft-tissue releases. Release of most soft-tissue .
