Introduction 11 7 10 8 3 11 10 2 4 6 11 Methods 2 4 1 Table 1 Matching of the two pump groups was performed based on the number of operations, the total duration of all operations, and the share of shaver usage Operation Time (min:s:frames) Shaver time (s) Gravity pump  Cyst removal 17:55:11 114  Meniscectomy 26:03:15 363  Meniscectomy 33:15:09 288  Meniscectomy 19:56:10 416  Meniscectomy 13:37:18 313  Meniscectomy 17:55:13 508  Meniscectomy 12:10:15 153  Meniscectomy 15:09:02 150  Debridement partial rupture of anterior cruciate ligament 16:30:03 290  Diagnostic 7:12:03   Total duration  179:45:24 43:15:0  Shaver time as percentage of total duration (%) 24.1 Automated pump  Meniscectomy 30:37:11 410  Meniscectomy 13:49:15 120  Meniscectomy 16:07:12 122  Meniscectomy 22:10:01 404  Meniscectomy 15:08:16 237  Meniscectomy 11:05:19 290  Meniscectomy 27:35:00 325  Meniscectomy 14:16:13 149  Debridement partial rupture of anterior cruciate ligament 17:41:10 284  Diagnostic 7:08:21   Total duration  175:40:18 39:01:0  Shaver time as percentage of total duration (%) 22.2 2 Table 2 Standard operation setting for the gravity and the automated pump  Gravity pump Automated pump Portals Anteromedial and anterolateral Anteromedial, anterolateral, and superomedial Pump settings  Indicated setting for knee arthroscopy is 50, which implies a preset pressure of 113 mmHg and a continuous flow of 90 ml/min Instrument set     11 11 1 11 Fig. 1 Three images of the disturbance turbidity, which consists of synovial fluid and small particles  1 9 SPSS U Results 1 1 2 U 2 Fig. 2 U  U 3 Fig. 3 a b U  Discussion 2 4 6 2 The found variation in the duration of disturbances per operation could have been caused by the condition of the knee joints, because this factor could not be completely eliminated with precise matching. With this knowledge, a future suggestion is to analyze a larger number of patients per pump group to determine possibly other significant differences in pump performance. Comparison of the operation phases independently showed similar results for the inspection phase compared to the total operation time, probably because this was the longest phase. Since the creation of portals was a relatively short phase, and the use of punches was absent for almost half of the operations, no significant differences were found. However, analysis of both groups internally showed that the presence of loose fibrous tissue was generally significantly higher in when an instrument was used (Phases 3 and 4). This is in accordance with the general expectation and confirms the applicability of this method for quantification of disturbances in the view. Concluding, this study shows that important disturbances as bleeding, air bubbles, and loose fibrous tissue are not affected by a pump system when performing a routine knee arthroscopy with a tourniquet. The most frequent disturbance turbidity is reduced by around 50% when using an automated pump. It is questionable if this justifies the use of an automated pump for straightforward arthroscopic knee surgeries using a tourniquet, since the purchase of an automated pump is more costly.