This illustration shows the patellar tendon sewn up after the patella has been removed.
Why remove a kneecap?
When a patellar fracture is comminuted - or star-shaped - it may be impossible to hold the fragments together with wires, and removal of this important bone may be the only option.
Rarely, disease or tumours may affect the patella, requiring the bone to be excised.
Peer-reviewed papersQuote from peer-reviewed paper:
"....Extensive comminution of the distal pole or a fragment of the patella which cannot be fixed internally is indication for partial patellectomy....Total patellectomy is indicated for comminuted fractures in which there are no large fragments to be stabilized by internal fixation...."
Citation: Sharafatvaziri A, Esfandiari S, Vosoughi F, Shayan-Moghadam R, Soleymani M. Patellectomy, an old treatment in patellar fracture which is still alive: A case report. Int J Surg Case Rep. 2024 May;118:109604. doi: 10.1016/j.ijscr.2024.109604. Epub 2024 Apr 10. PMID: 38615464; PMCID: PMC11033151.
Quote from peer-reviewed paper:
"....Most common tumours affecting the patella in patients less than 40 include giant cell tumour, chondroblastoma, aneurysmal bone cyst, osteoid osteoma and solitary bone cyst; while in patients over 40, metastatic tumours are the most common....."
Citation: Alqasim E, Aljowder A, Alammari N, Joudeh AA. Total patellectomy with extensor mechanism reconstruction following pathological fracture due to patellar Ewing's sarcoma. BMJ Case Rep. 2018 Feb 7;2018:bcr2017222853. doi: 10.1136/bcr-2017-222853. PMID: 29437710; PMCID: PMC5836618.
Surgical technique of patellectomy
Because the patella is embedded in the tendon of the quadriceps muscle, it is really 'shelled out' from its bed in the tendon without actually cutting right through the tendon.
The patella helps to improve the power of extension of the knee, but a patient can still straighten the lower limb and bear weight without a patella. It is just a bit inefficient. The patient is likely to have some limitation of extension afterwards, and there may be some calcification where the patella has been shelled out.
Peer-reviewed papersQuote from peer-reviewed paper:
"....Total patellectomy can lead to a relative satisfaction in performing activities of daily living....."
Citation: Sharafatvaziri A, Esfandiari S, Vosoughi F, Shayan-Moghadam R, Soleymani M. Patellectomy, an old treatment in patellar fracture which is still alive: A case report. Int J Surg Case Rep. 2024 May;118:109604. doi: 10.1016/j.ijscr.2024.109604. Epub 2024 Apr 10. PMID: 38615464; PMCID: PMC11033151.
Quote from peer-reviewed paper:
"....Calcification was the most commonly observed complication (35.5%) following total patellectomy...."
Citation: Deng X, Zhu L, Hu H, Zhu J, Liu W, Zhang J, Yang S, Ye Z, Guan H, Zhang B, Cheng X, Zhang Y. Comparison of total patellectomy and osteosynthesis with tension band wiring in patients with highly comminuted patella fractures: a 10-20-year follow-up study. J Orthop Surg Res. 2021 Aug 13;16(1):497. doi: 10.1186/s13018-021-02656-3. PMID: 34389023; PMCID: PMC8361621.
Quote from peer-reviewed paper:
"....Acute rupture of the knee extensor mechanism after patellectomy is extremely rare....."
Citation: Fujimura K, Sakuraba K, Kamura S, Miyazaki K, Kobara N, Terada K, Miyahara H. Reconstruction of Acute Patellar Tendon Rupture after Patellectomy. Case Rep Orthop. 2018 Apr 1;2018:7549476. doi: 10.1155/2018/7549476. PMID: 29808145; PMCID: PMC5902117.
Knee replacement after patellectomy
Removal of the patella does not preclude later knee replacement.
Peer-reviewed papersQuote from peer-reviewed paper:
"Despite the mechanical disadvantage to the knee extensor mechanism rendered by a previous patellectomy, TKA for tibiofemoral arthrosis in these patients relieved pain and restored function, but function was on average lower than that in patients with intact patellae."
Citation: Yao R, Lyons MC, Howard JL, McAuley JP. Does patellectomy jeopardize function after TKA? Clin Orthop Relat Res. 2013 Feb;471(2):544-53. doi: 10.1007/s11999-012-2653-4. PMID: 23090656; PMCID: PMC3549151.
Forum discussions
- OS says a patellectomy vs PFJR for pain relief. Isn't this an old procedure?
Discussion about patellectomy versus patellofemoral joint replacement.